Rebase master to b117

75 files changed, 5278 insertions, 2305 deletions

diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index 3a9598a92..d5e5aa544 100644
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -124,6 +124,7 @@
 #include <sys/arc.h>
 #include <sys/refcount.h>
 #include <sys/vdev.h>
+#include <sys/vdev_impl.h>
 #ifdef _KERNEL
 #include <sys/vmsystm.h>
 #include <vm/anon.h>
@@ -397,6 +398,7 @@ static arc_state_t	*arc_l2c_only;
 
 static int		arc_no_grow;	/* Don't try to grow cache size */
 static uint64_t		arc_tempreserve;
+static uint64_t		arc_loaned_bytes;
 static uint64_t		arc_meta_used;
 static uint64_t		arc_meta_limit;
 static uint64_t		arc_meta_max = 0;
@@ -610,7 +612,7 @@ typedef struct l2arc_write_callback {
 struct l2arc_buf_hdr {
 	/* protected by arc_buf_hdr  mutex */
 	l2arc_dev_t	*b_dev;			/* L2ARC device */
-	daddr_t		b_daddr;		/* disk address, offset byte */
+	uint64_t	b_daddr;		/* disk address, offset byte */
 };
 
 typedef struct l2arc_data_free {
@@ -1203,6 +1205,41 @@ arc_buf_alloc(spa_t *spa, int size, void *tag, arc_buf_contents_t type)
 	return (buf);
 }
 
+static char *arc_onloan_tag = "onloan";
+
+/*
+ * Loan out an anonymous arc buffer. Loaned buffers are not counted as in
+ * flight data by arc_tempreserve_space() until they are "returned". Loaned
+ * buffers must be returned to the arc before they can be used by the DMU or
+ * freed.
+ */
+arc_buf_t *
+arc_loan_buf(spa_t *spa, int size)
+{
+	arc_buf_t *buf;
+
+	buf = arc_buf_alloc(spa, size, arc_onloan_tag, ARC_BUFC_DATA);
+
+	atomic_add_64(&arc_loaned_bytes, size);
+	return (buf);
+}
+
+/*
+ * Return a loaned arc buffer to the arc.
+ */
+void
+arc_return_buf(arc_buf_t *buf, void *tag)
+{
+	arc_buf_hdr_t *hdr = buf->b_hdr;
+
+	ASSERT(hdr->b_state == arc_anon);
+	ASSERT(buf->b_data != NULL);
+	VERIFY(refcount_remove(&hdr->b_refcnt, arc_onloan_tag) == 0);
+	VERIFY(refcount_add(&hdr->b_refcnt, tag) == 1);
+
+	atomic_add_64(&arc_loaned_bytes, -hdr->b_size);
+}
+
 static arc_buf_t *
 arc_buf_clone(arc_buf_t *from)
 {
@@ -2504,7 +2541,6 @@ arc_read(zio_t *pio, spa_t *spa, blkptr_t *bp, arc_buf_t *pbuf,
     uint32_t *arc_flags, const zbookmark_t *zb)
 {
 	int err;
-	arc_buf_hdr_t *hdr = pbuf->b_hdr;
 
 	ASSERT(!refcount_is_zero(&pbuf->b_hdr->b_refcnt));
 	ASSERT3U((char *)bp - (char *)pbuf->b_data, <, pbuf->b_hdr->b_size);
@@ -2512,9 +2548,8 @@ arc_read(zio_t *pio, spa_t *spa, blkptr_t *bp, arc_buf_t *pbuf,
 
 	err = arc_read_nolock(pio, spa, bp, done, private, priority,
 	    zio_flags, arc_flags, zb);
-
-	ASSERT3P(hdr, ==, pbuf->b_hdr);
 	rw_exit(&pbuf->b_lock);
+
 	return (err);
 }
 
@@ -2604,7 +2639,7 @@ top:
 		uint64_t size = BP_GET_LSIZE(bp);
 		arc_callback_t	*acb;
 		vdev_t *vd = NULL;
-		daddr_t addr;
+		uint64_t addr;
 		boolean_t devw = B_FALSE;
 
 		if (hdr == NULL) {
@@ -2923,6 +2958,7 @@ arc_release(arc_buf_t *buf, void *tag)
 	kmutex_t *hash_lock;
 	l2arc_buf_hdr_t *l2hdr;
 	uint64_t buf_size;
+	boolean_t released = B_FALSE;
 
 	rw_enter(&buf->b_lock, RW_WRITER);
 	hdr = buf->b_hdr;
@@ -2938,12 +2974,12 @@ arc_release(arc_buf_t *buf, void *tag)
 		ASSERT(buf->b_efunc == NULL);
 		arc_buf_thaw(buf);
 		rw_exit(&buf->b_lock);
-		return;
+		released = B_TRUE;
+	} else {
+		hash_lock = HDR_LOCK(hdr);
+		mutex_enter(hash_lock);
 	}
 
-	hash_lock = HDR_LOCK(hdr);
-	mutex_enter(hash_lock);
-
 	l2hdr = hdr->b_l2hdr;
 	if (l2hdr) {
 		mutex_enter(&l2arc_buflist_mtx);
@@ -2951,6 +2987,9 @@ arc_release(arc_buf_t *buf, void *tag)
 		buf_size = hdr->b_size;
 	}
 
+	if (released)
+		goto out;
+
 	/*
 	 * Do we have more than one buf?
 	 */
@@ -3018,6 +3057,7 @@ arc_release(arc_buf_t *buf, void *tag)
 	buf->b_efunc = NULL;
 	buf->b_private = NULL;
 
+out:
 	if (l2hdr) {
 		list_remove(l2hdr->b_dev->l2ad_buflist, hdr);
 		kmem_free(l2hdr, sizeof (l2arc_buf_hdr_t));
@@ -3311,10 +3351,9 @@ arc_free(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
 }
 
 static int
-arc_memory_throttle(uint64_t reserve, uint64_t txg)
+arc_memory_throttle(uint64_t reserve, uint64_t inflight_data, uint64_t txg)
 {
 #ifdef _KERNEL
-	uint64_t inflight_data = arc_anon->arcs_size;
 	uint64_t available_memory = ptob(freemem);
 	static uint64_t page_load = 0;
 	static uint64_t last_txg = 0;
@@ -3376,6 +3415,7 @@ int
 arc_tempreserve_space(uint64_t reserve, uint64_t txg)
 {
 	int error;
+	uint64_t anon_size;
 
 #ifdef ZFS_DEBUG
 	/*
@@ -3392,11 +3432,18 @@ arc_tempreserve_space(uint64_t reserve, uint64_t txg)
 		return (ENOMEM);
 
 	/*
+	 * Don't count loaned bufs as in flight dirty data to prevent long
+	 * network delays from blocking transactions that are ready to be
+	 * assigned to a txg.
+	 */
+	anon_size = MAX((int64_t)(arc_anon->arcs_size - arc_loaned_bytes), 0);
+
+	/*
 	 * Writes will, almost always, require additional memory allocations
 	 * in order to compress/encrypt/etc the data.  We therefor need to
 	 * make sure that there is sufficient available memory for this.
 	 */
-	if (error = arc_memory_throttle(reserve, txg))
+	if (error = arc_memory_throttle(reserve, anon_size, txg))
 		return (error);
 
 	/*
@@ -3406,8 +3453,9 @@ arc_tempreserve_space(uint64_t reserve, uint64_t txg)
 	 * Note: if two requests come in concurrently, we might let them
 	 * both succeed, when one of them should fail.  Not a huge deal.
 	 */
-	if (reserve + arc_tempreserve + arc_anon->arcs_size > arc_c / 2 &&
-	    arc_anon->arcs_size > arc_c / 4) {
+
+	if (reserve + arc_tempreserve + anon_size > arc_c / 2 &&
+	    anon_size > arc_c / 4) {
 		dprintf("failing, arc_tempreserve=%lluK anon_meta=%lluK "
 		    "anon_data=%lluK tempreserve=%lluK arc_c=%lluK\n",
 		    arc_tempreserve>>10,
@@ -3592,6 +3640,8 @@ arc_fini(void)
 	mutex_destroy(&zfs_write_limit_lock);
 
 	buf_fini();
+
+	ASSERT(arc_loaned_bytes == 0);
 }
 
 /*
@@ -4486,7 +4536,7 @@ l2arc_vdev_present(vdev_t *vd)
  * validated the vdev and opened it.
  */
 void
-l2arc_add_vdev(spa_t *spa, vdev_t *vd, uint64_t start, uint64_t end)
+l2arc_add_vdev(spa_t *spa, vdev_t *vd)
 {
 	l2arc_dev_t *adddev;
 
@@ -4500,8 +4550,8 @@ l2arc_add_vdev(spa_t *spa, vdev_t *vd, uint64_t start, uint64_t end)
 	adddev->l2ad_vdev = vd;
 	adddev->l2ad_write = l2arc_write_max;
 	adddev->l2ad_boost = l2arc_write_boost;
-	adddev->l2ad_start = start;
-	adddev->l2ad_end = end;
+	adddev->l2ad_start = VDEV_LABEL_START_SIZE;
+	adddev->l2ad_end = VDEV_LABEL_START_SIZE + vdev_get_min_asize(vd);
 	adddev->l2ad_hand = adddev->l2ad_start;
 	adddev->l2ad_evict = adddev->l2ad_start;
 	adddev->l2ad_first = B_TRUE;
diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c
index 113fa1f03..1b6f242dd 100644
--- a/module/zfs/dbuf.c
+++ b/module/zfs/dbuf.c
@@ -329,7 +329,7 @@ dbuf_verify(dmu_buf_impl_t *db)
 		if (db->db_parent == dn->dn_dbuf) {
 			/* db is pointed to by the dnode */
 			/* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */
-			if (db->db.db_object == DMU_META_DNODE_OBJECT)
+			if (DMU_OBJECT_IS_SPECIAL(db->db.db_object))
 				ASSERT(db->db_parent == NULL);
 			else
 				ASSERT(db->db_parent != NULL);
@@ -465,15 +465,15 @@ dbuf_read_impl(dmu_buf_impl_t *db, zio_t *zio, uint32_t *flags)
 	ASSERT(db->db_buf == NULL);
 
 	if (db->db_blkid == DB_BONUS_BLKID) {
-		int bonuslen = dn->dn_bonuslen;
+		int bonuslen = MIN(dn->dn_bonuslen, dn->dn_phys->dn_bonuslen);
 
 		ASSERT3U(bonuslen, <=, db->db.db_size);
 		db->db.db_data = zio_buf_alloc(DN_MAX_BONUSLEN);
 		arc_space_consume(DN_MAX_BONUSLEN, ARC_SPACE_OTHER);
 		if (bonuslen < DN_MAX_BONUSLEN)
 			bzero(db->db.db_data, DN_MAX_BONUSLEN);
-		bcopy(DN_BONUS(dn->dn_phys), db->db.db_data,
-		    bonuslen);
+		if (bonuslen)
+			bcopy(DN_BONUS(dn->dn_phys), db->db.db_data, bonuslen);
 		dbuf_update_data(db);
 		db->db_state = DB_CACHED;
 		mutex_exit(&db->db_mtx);
@@ -908,15 +908,11 @@ dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 	 * Shouldn't dirty a regular buffer in syncing context.  Private
 	 * objects may be dirtied in syncing context, but only if they
 	 * were already pre-dirtied in open context.
-	 * XXX We may want to prohibit dirtying in syncing context even
-	 * if they did pre-dirty.
 	 */
 	ASSERT(!dmu_tx_is_syncing(tx) ||
 	    BP_IS_HOLE(dn->dn_objset->os_rootbp) ||
-	    dn->dn_object == DMU_META_DNODE_OBJECT ||
-	    dn->dn_objset->os_dsl_dataset == NULL ||
-	    dsl_dir_is_private(dn->dn_objset->os_dsl_dataset->ds_dir));
-
+	    DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
+	    dn->dn_objset->os_dsl_dataset == NULL);
 	/*
 	 * We make this assert for private objects as well, but after we
 	 * check if we're already dirty.  They are allowed to re-dirty
@@ -975,7 +971,8 @@ dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 	/*
 	 * Only valid if not already dirty.
 	 */
-	ASSERT(dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
+	ASSERT(dn->dn_object == 0 ||
+	    dn->dn_dirtyctx == DN_UNDIRTIED || dn->dn_dirtyctx ==
 	    (dmu_tx_is_syncing(tx) ? DN_DIRTY_SYNC : DN_DIRTY_OPEN));
 
 	ASSERT3U(dn->dn_nlevels, >, db->db_level);
@@ -987,15 +984,13 @@ dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
 
 	/*
 	 * We should only be dirtying in syncing context if it's the
-	 * mos, a spa os, or we're initializing the os.  However, we are
-	 * allowed to dirty in syncing context provided we already
-	 * dirtied it in open context.  Hence we must make this
-	 * assertion only if we're not already dirty.
+	 * mos or we're initializing the os or it's a special object.
+	 * However, we are allowed to dirty in syncing context provided
+	 * we already dirtied it in open context.  Hence we must make
+	 * this assertion only if we're not already dirty.
 	 */
-	ASSERT(!dmu_tx_is_syncing(tx) ||
-	    os->os_dsl_dataset == NULL ||
-	    !dsl_dir_is_private(os->os_dsl_dataset->ds_dir) ||
-	    !BP_IS_HOLE(os->os_rootbp));
+	ASSERT(!dmu_tx_is_syncing(tx) || DMU_OBJECT_IS_SPECIAL(dn->dn_object) ||
+	    os->os_dsl_dataset == NULL || BP_IS_HOLE(os->os_rootbp));
 	ASSERT(db->db.db_size != 0);
 
 	dprintf_dbuf(db, "size=%llx\n", (u_longlong_t)db->db.db_size);
@@ -1312,6 +1307,68 @@ dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx)
 }
 
 /*
+ * Directly assign a provided arc buf to a given dbuf if it's not referenced
+ * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf.
+ */
+void
+dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx)
+{
+	ASSERT(!refcount_is_zero(&db->db_holds));
+	ASSERT(db->db_dnode->dn_object != DMU_META_DNODE_OBJECT);
+	ASSERT(db->db_blkid != DB_BONUS_BLKID);
+	ASSERT(db->db_level == 0);
+	ASSERT(DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA);
+	ASSERT(buf != NULL);
+	ASSERT(arc_buf_size(buf) == db->db.db_size);
+	ASSERT(tx->tx_txg != 0);
+
+	arc_return_buf(buf, db);
+	ASSERT(arc_released(buf));
+
+	mutex_enter(&db->db_mtx);
+
+	while (db->db_state == DB_READ || db->db_state == DB_FILL)
+		cv_wait(&db->db_changed, &db->db_mtx);
+
+	ASSERT(db->db_state == DB_CACHED || db->db_state == DB_UNCACHED);
+
+	if (db->db_state == DB_CACHED &&
+	    refcount_count(&db->db_holds) - 1 > db->db_dirtycnt) {
+		mutex_exit(&db->db_mtx);
+		(void) dbuf_dirty(db, tx);
+		bcopy(buf->b_data, db->db.db_data, db->db.db_size);
+		VERIFY(arc_buf_remove_ref(buf, db) == 1);
+		return;
+	}
+
+	if (db->db_state == DB_CACHED) {
+		dbuf_dirty_record_t *dr = db->db_last_dirty;
+
+		ASSERT(db->db_buf != NULL);
+		if (dr != NULL && dr->dr_txg == tx->tx_txg) {
+			ASSERT(dr->dt.dl.dr_data == db->db_buf);
+			if (!arc_released(db->db_buf)) {
+				ASSERT(dr->dt.dl.dr_override_state ==
+				    DR_OVERRIDDEN);
+				arc_release(db->db_buf, db);
+			}
+			dr->dt.dl.dr_data = buf;
+			VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1);
+		} else if (dr == NULL || dr->dt.dl.dr_data != db->db_buf) {
+			arc_release(db->db_buf, db);
+			VERIFY(arc_buf_remove_ref(db->db_buf, db) == 1);
+		}
+		db->db_buf = NULL;
+	}
+	ASSERT(db->db_buf == NULL);
+	dbuf_set_data(db, buf);
+	db->db_state = DB_FILL;
+	mutex_exit(&db->db_mtx);
+	(void) dbuf_dirty(db, tx);
+	dbuf_fill_done(db, tx);
+}
+
+/*
  * "Clear" the contents of this dbuf.  This will mark the dbuf
  * EVICTING and clear *most* of its references.  Unfortunetely,
  * when we are not holding the dn_dbufs_mtx, we can't clear the
@@ -1855,6 +1912,19 @@ dmu_buf_get_user(dmu_buf_t *db_fake)
 	return (db->db_user_ptr);
 }
 
+boolean_t
+dmu_buf_freeable(dmu_buf_t *dbuf)
+{
+	boolean_t res = B_FALSE;
+	dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbuf;
+
+	if (db->db_blkptr)
+		res = dsl_dataset_block_freeable(db->db_objset->os_dsl_dataset,
+		    db->db_blkptr->blk_birth);
+
+	return (res);
+}
+
 static void
 dbuf_check_blkptr(dnode_t *dn, dmu_buf_impl_t *db)
 {
@@ -1943,7 +2013,6 @@ dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 	dnode_t *dn = db->db_dnode;
 	objset_impl_t *os = dn->dn_objset;
 	uint64_t txg = tx->tx_txg;
-	int blksz;
 
 	ASSERT(dmu_tx_is_syncing(tx));
 
@@ -2049,32 +2118,25 @@ dbuf_sync_leaf(dbuf_dirty_record_t *dr, dmu_tx_t *tx)
 		return;
 	}
 
-	if (db->db_state != DB_NOFILL) {
-		blksz = arc_buf_size(*datap);
-
-		if (dn->dn_object != DMU_META_DNODE_OBJECT) {
-			/*
-			 * If this buffer is currently "in use" (i.e., there
-			 * are active holds and db_data still references it),
-			 * then make a copy before we start the write so that
-			 * any modifications from the open txg will not leak
-			 * into this write.
-			 *
-			 * NOTE: this copy does not need to be made for
-			 * objects only modified in the syncing context (e.g.
-			 * DNONE_DNODE blocks).
-			 */
-			if (refcount_count(&db->db_holds) > 1 &&
-			    *datap == db->db_buf) {
-				arc_buf_contents_t type =
-				    DBUF_GET_BUFC_TYPE(db);
-				*datap =
-				    arc_buf_alloc(os->os_spa, blksz, db, type);
-				bcopy(db->db.db_data, (*datap)->b_data, blksz);
-			}
-		}
-
-		ASSERT(*datap != NULL);
+	if (db->db_state != DB_NOFILL &&
+	    dn->dn_object != DMU_META_DNODE_OBJECT &&
+	    refcount_count(&db->db_holds) > 1 &&
+	    *datap == db->db_buf) {
+		/*
+		 * If this buffer is currently "in use" (i.e., there
+		 * are active holds and db_data still references it),
+		 * then make a copy before we start the write so that
+		 * any modifications from the open txg will not leak
+		 * into this write.
+		 *
+		 * NOTE: this copy does not need to be made for
+		 * objects only modified in the syncing context (e.g.
+		 * DNONE_DNODE blocks).
+		 */
+		int blksz = arc_buf_size(*datap);
+		arc_buf_contents_t type = DBUF_GET_BUFC_TYPE(db);
+		*datap = arc_buf_alloc(os->os_spa, blksz, db, type);
+		bcopy(db->db.db_data, (*datap)->b_data, blksz);
 	}
 	db->db_data_pending = dr;
 
diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c
index b6205bd50..785c7c621 100644
--- a/module/zfs/dmu.c
+++ b/module/zfs/dmu.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -85,6 +85,8 @@ const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES] = {
 	{	byteswap_uint64_array,	TRUE,	"FUID table size"	},
 	{	zap_byteswap,		TRUE,	"DSL dataset next clones"},
 	{	zap_byteswap,		TRUE,	"scrub work queue"	},
+	{	zap_byteswap,		TRUE,	"ZFS user/group used"	},
+	{	zap_byteswap,		TRUE,	"ZFS user/group quota"	},
 };
 
 int
@@ -180,22 +182,22 @@ dmu_bonus_hold(objset_t *os, uint64_t object, void *tag, dmu_buf_t **dbp)
  * whose dnodes are in the same block.
  */
 static int
-dmu_buf_hold_array_by_dnode(dnode_t *dn, uint64_t offset,
-    uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp)
+dmu_buf_hold_array_by_dnode(dnode_t *dn, uint64_t offset, uint64_t length,
+    int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp, uint32_t flags)
 {
 	dsl_pool_t *dp = NULL;
 	dmu_buf_t **dbp;
 	uint64_t blkid, nblks, i;
-	uint32_t flags;
+	uint32_t dbuf_flags;
 	int err;
 	zio_t *zio;
 	hrtime_t start;
 
 	ASSERT(length <= DMU_MAX_ACCESS);
 
-	flags = DB_RF_CANFAIL | DB_RF_NEVERWAIT;
-	if (length > zfetch_array_rd_sz)
-		flags |= DB_RF_NOPREFETCH;
+	dbuf_flags = DB_RF_CANFAIL | DB_RF_NEVERWAIT;
+	if (flags & DMU_READ_NO_PREFETCH || length > zfetch_array_rd_sz)
+		dbuf_flags |= DB_RF_NOPREFETCH;
 
 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
 	if (dn->dn_datablkshift) {
@@ -233,7 +235,7 @@ dmu_buf_hold_array_by_dnode(dnode_t *dn, uint64_t offset,
 		/* initiate async i/o */
 		if (read) {
 			rw_exit(&dn->dn_struct_rwlock);
-			(void) dbuf_read(db, zio, flags);
+			(void) dbuf_read(db, zio, dbuf_flags);
 			rw_enter(&dn->dn_struct_rwlock, RW_READER);
 		}
 		dbp[i] = &db->db;
@@ -285,7 +287,7 @@ dmu_buf_hold_array(objset_t *os, uint64_t object, uint64_t offset,
 		return (err);
 
 	err = dmu_buf_hold_array_by_dnode(dn, offset, length, read, tag,
-	    numbufsp, dbpp);
+	    numbufsp, dbpp, DMU_READ_PREFETCH);
 
 	dnode_rele(dn, FTAG);
 
@@ -300,7 +302,7 @@ dmu_buf_hold_array_by_bonus(dmu_buf_t *db, uint64_t offset,
 	int err;
 
 	err = dmu_buf_hold_array_by_dnode(dn, offset, length, read, tag,
-	    numbufsp, dbpp);
+	    numbufsp, dbpp, DMU_READ_PREFETCH);
 
 	return (err);
 }
@@ -442,7 +444,8 @@ dmu_free_long_range_impl(objset_t *os, dnode_t *dn, uint64_t offset,
 	object_size = align == 1 ? dn->dn_datablksz :
 	    (dn->dn_maxblkid + 1) << dn->dn_datablkshift;
 
-	if (trunc || (end = offset + length) > object_size)
+	end = offset + length;
+	if (trunc || end > object_size)
 		end = object_size;
 	if (end <= offset)
 		return (0);
@@ -450,6 +453,7 @@ dmu_free_long_range_impl(objset_t *os, dnode_t *dn, uint64_t offset,
 
 	while (length) {
 		start = end;
+		/* assert(offset <= start) */
 		err = get_next_chunk(dn, &start, offset);
 		if (err)
 			return (err);
@@ -540,7 +544,7 @@ dmu_free_range(objset_t *os, uint64_t object, uint64_t offset,
 
 int
 dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
-    void *buf)
+    void *buf, uint32_t flags)
 {
 	dnode_t *dn;
 	dmu_buf_t **dbp;
@@ -570,7 +574,7 @@ dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 		 * to be reading in parallel.
 		 */
 		err = dmu_buf_hold_array_by_dnode(dn, offset, mylen,
-		    TRUE, FTAG, &numbufs, &dbp);
+		    TRUE, FTAG, &numbufs, &dbp, flags);
 		if (err)
 			break;
 
@@ -810,6 +814,58 @@ dmu_write_pages(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 }
 #endif
 
+/*
+ * Allocate a loaned anonymous arc buffer.
+ */
+arc_buf_t *
+dmu_request_arcbuf(dmu_buf_t *handle, int size)
+{
+	dnode_t *dn = ((dmu_buf_impl_t *)handle)->db_dnode;
+
+	return (arc_loan_buf(dn->dn_objset->os_spa, size));
+}
+
+/*
+ * Free a loaned arc buffer.
+ */
+void
+dmu_return_arcbuf(arc_buf_t *buf)
+{
+	arc_return_buf(buf, FTAG);
+	VERIFY(arc_buf_remove_ref(buf, FTAG) == 1);
+}
+
+/*
+ * When possible directly assign passed loaned arc buffer to a dbuf.
+ * If this is not possible copy the contents of passed arc buf via
+ * dmu_write().
+ */
+void
+dmu_assign_arcbuf(dmu_buf_t *handle, uint64_t offset, arc_buf_t *buf,
+    dmu_tx_t *tx)
+{
+	dnode_t *dn = ((dmu_buf_impl_t *)handle)->db_dnode;
+	dmu_buf_impl_t *db;
+	uint32_t blksz = (uint32_t)arc_buf_size(buf);
+	uint64_t blkid;
+
+	rw_enter(&dn->dn_struct_rwlock, RW_READER);
+	blkid = dbuf_whichblock(dn, offset);
+	VERIFY((db = dbuf_hold(dn, blkid, FTAG)) != NULL);
+	rw_exit(&dn->dn_struct_rwlock);
+
+	if (offset == db->db.db_offset && blksz == db->db.db_size) {
+		dbuf_assign_arcbuf(db, buf, tx);
+		dbuf_rele(db, FTAG);
+	} else {
+		dbuf_rele(db, FTAG);
+		ASSERT(dn->dn_objset->os.os == dn->dn_objset);
+		dmu_write(&dn->dn_objset->os, dn->dn_object, offset, blksz,
+		    buf->b_data, tx);
+		dmu_return_arcbuf(buf);
+	}
+}
+
 typedef struct {
 	dbuf_dirty_record_t	*dr;
 	dmu_sync_cb_t		*done;
diff --git a/module/zfs/dmu_object.c b/module/zfs/dmu_object.c
index 1b9247d66..1f91fc1ad 100644
--- a/module/zfs/dmu_object.c
+++ b/module/zfs/dmu_object.c
@@ -19,12 +19,10 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/dmu.h>
 #include <sys/dmu_objset.h>
 #include <sys/dmu_tx.h>
@@ -108,22 +106,56 @@ dmu_object_claim(objset_t *os, uint64_t object, dmu_object_type_t ot,
 
 int
 dmu_object_reclaim(objset_t *os, uint64_t object, dmu_object_type_t ot,
-    int blocksize, dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
+    int blocksize, dmu_object_type_t bonustype, int bonuslen)
 {
 	dnode_t *dn;
+	dmu_tx_t *tx;
+	int nblkptr;
 	int err;
 
-	if (object == DMU_META_DNODE_OBJECT && !dmu_tx_private_ok(tx))
+	if (object == DMU_META_DNODE_OBJECT)
 		return (EBADF);
 
 	err = dnode_hold_impl(os->os, object, DNODE_MUST_BE_ALLOCATED,
 	    FTAG, &dn);
 	if (err)
 		return (err);
+
+	if (dn->dn_type == ot && dn->dn_datablksz == blocksize &&
+	    dn->dn_bonustype == bonustype && dn->dn_bonuslen == bonuslen) {
+		/* nothing is changing, this is a noop */
+		dnode_rele(dn, FTAG);
+		return (0);
+	}
+
+	nblkptr = 1 + ((DN_MAX_BONUSLEN - bonuslen) >> SPA_BLKPTRSHIFT);
+
+	/*
+	 * If we are losing blkptrs or changing the block size this must
+	 * be a new file instance.   We must clear out the previous file
+	 * contents before we can change this type of metadata in the dnode.
+	 */
+	if (dn->dn_nblkptr > nblkptr || dn->dn_datablksz != blocksize) {
+		err = dmu_free_long_range(os, object, 0, DMU_OBJECT_END);
+		if (err)
+			goto out;
+	}
+
+	tx = dmu_tx_create(os);
+	dmu_tx_hold_bonus(tx, object);
+	err = dmu_tx_assign(tx, TXG_WAIT);
+	if (err) {
+		dmu_tx_abort(tx);
+		goto out;
+	}
+
 	dnode_reallocate(dn, ot, blocksize, bonustype, bonuslen, tx);
+
+	dmu_tx_commit(tx);
+out:
 	dnode_rele(dn, FTAG);
 
-	return (0);
+	return (err);
 }
 
 int
diff --git a/module/zfs/dmu_objset.c b/module/zfs/dmu_objset.c
index c9e00d511..e962c4b88 100644
--- a/module/zfs/dmu_objset.c
+++ b/module/zfs/dmu_objset.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -164,10 +164,15 @@ dmu_objset_byteswap(void *buf, size_t size)
 {
 	objset_phys_t *osp = buf;
 
-	ASSERT(size == sizeof (objset_phys_t));
+	ASSERT(size == OBJSET_OLD_PHYS_SIZE || size == sizeof (objset_phys_t));
 	dnode_byteswap(&osp->os_meta_dnode);
 	byteswap_uint64_array(&osp->os_zil_header, sizeof (zil_header_t));
 	osp->os_type = BSWAP_64(osp->os_type);
+	osp->os_flags = BSWAP_64(osp->os_flags);
+	if (size == sizeof (objset_phys_t)) {
+		dnode_byteswap(&osp->os_userused_dnode);
+		dnode_byteswap(&osp->os_groupused_dnode);
+	}
 }
 
 int
@@ -210,12 +215,30 @@ dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 				err = EIO;
 			return (err);
 		}
+
+		/* Increase the blocksize if we are permitted. */
+		if (spa_version(spa) >= SPA_VERSION_USERSPACE &&
+		    arc_buf_size(osi->os_phys_buf) < sizeof (objset_phys_t)) {
+			arc_buf_t *buf = arc_buf_alloc(spa,
+			    sizeof (objset_phys_t), &osi->os_phys_buf,
+			    ARC_BUFC_METADATA);
+			bzero(buf->b_data, sizeof (objset_phys_t));
+			bcopy(osi->os_phys_buf->b_data, buf->b_data,
+			    arc_buf_size(osi->os_phys_buf));
+			(void) arc_buf_remove_ref(osi->os_phys_buf,
+			    &osi->os_phys_buf);
+			osi->os_phys_buf = buf;
+		}
+
 		osi->os_phys = osi->os_phys_buf->b_data;
+		osi->os_flags = osi->os_phys->os_flags;
 	} else {
-		osi->os_phys_buf = arc_buf_alloc(spa, sizeof (objset_phys_t),
+		int size = spa_version(spa) >= SPA_VERSION_USERSPACE ?
+		    sizeof (objset_phys_t) : OBJSET_OLD_PHYS_SIZE;
+		osi->os_phys_buf = arc_buf_alloc(spa, size,
 		    &osi->os_phys_buf, ARC_BUFC_METADATA);
 		osi->os_phys = osi->os_phys_buf->b_data;
-		bzero(osi->os_phys, sizeof (objset_phys_t));
+		bzero(osi->os_phys, size);
 	}
 
 	/*
@@ -276,6 +299,12 @@ dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 
 	osi->os_meta_dnode = dnode_special_open(osi,
 	    &osi->os_phys->os_meta_dnode, DMU_META_DNODE_OBJECT);
+	if (arc_buf_size(osi->os_phys_buf) >= sizeof (objset_phys_t)) {
+		osi->os_userused_dnode = dnode_special_open(osi,
+		    &osi->os_phys->os_userused_dnode, DMU_USERUSED_OBJECT);
+		osi->os_groupused_dnode = dnode_special_open(osi,
+		    &osi->os_phys->os_groupused_dnode, DMU_GROUPUSED_OBJECT);
+	}
 
 	/*
 	 * We should be the only thread trying to do this because we
@@ -456,13 +485,15 @@ dmu_objset_evict(dsl_dataset_t *ds, void *arg)
 	os.os = osi;
 	(void) dmu_objset_evict_dbufs(&os);
 
-	ASSERT3P(list_head(&osi->os_dnodes), ==, osi->os_meta_dnode);
-	ASSERT3P(list_tail(&osi->os_dnodes), ==, osi->os_meta_dnode);
-	ASSERT3P(list_head(&osi->os_meta_dnode->dn_dbufs), ==, NULL);
-
 	dnode_special_close(osi->os_meta_dnode);
+	if (osi->os_userused_dnode) {
+		dnode_special_close(osi->os_userused_dnode);
+		dnode_special_close(osi->os_groupused_dnode);
+	}
 	zil_free(osi->os_zil);
 
+	ASSERT3P(list_head(&osi->os_dnodes), ==, NULL);
+
 	VERIFY(arc_buf_remove_ref(osi->os_phys_buf, &osi->os_phys_buf) == 1);
 	mutex_destroy(&osi->os_lock);
 	mutex_destroy(&osi->os_obj_lock);
@@ -520,6 +551,10 @@ dmu_objset_create_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 	ASSERT(type != DMU_OST_ANY);
 	ASSERT(type < DMU_OST_NUMTYPES);
 	osi->os_phys->os_type = type;
+	if (dmu_objset_userused_enabled(osi)) {
+		osi->os_phys->os_flags |= OBJSET_FLAG_USERACCOUNTING_COMPLETE;
+		osi->os_flags = osi->os_phys->os_flags;
+	}
 
 	dsl_dataset_dirty(ds, tx);
 
@@ -704,13 +739,33 @@ struct snaparg {
 	char *snapname;
 	char failed[MAXPATHLEN];
 	boolean_t checkperms;
-	list_t objsets;
+	nvlist_t *props;
 };
 
-struct osnode {
-	list_node_t node;
-	objset_t *os;
-};
+static int
+snapshot_check(void *arg1, void *arg2, dmu_tx_t *tx)
+{
+	objset_t *os = arg1;
+	struct snaparg *sn = arg2;
+
+	/* The props have already been checked by zfs_check_userprops(). */
+
+	return (dsl_dataset_snapshot_check(os->os->os_dsl_dataset,
+	    sn->snapname, tx));
+}
+
+static void
+snapshot_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
+{
+	objset_t *os = arg1;
+	dsl_dataset_t *ds = os->os->os_dsl_dataset;
+	struct snaparg *sn = arg2;
+
+	dsl_dataset_snapshot_sync(ds, sn->snapname, cr, tx);
+
+	if (sn->props)
+		dsl_props_set_sync(ds->ds_prev, sn->props, cr, tx);
+}
 
 static int
 dmu_objset_snapshot_one(char *name, void *arg)
@@ -747,13 +802,8 @@ dmu_objset_snapshot_one(char *name, void *arg)
 	 */
 	err = zil_suspend(dmu_objset_zil(os));
 	if (err == 0) {
-		struct osnode *osn;
-		dsl_sync_task_create(sn->dstg, dsl_dataset_snapshot_check,
-		    dsl_dataset_snapshot_sync, os->os->os_dsl_dataset,
-		    sn->snapname, 3);
-		osn = kmem_alloc(sizeof (struct osnode), KM_SLEEP);
-		osn->os = os;
-		list_insert_tail(&sn->objsets, osn);
+		dsl_sync_task_create(sn->dstg, snapshot_check,
+		    snapshot_sync, os, sn, 3);
 	} else {
 		dmu_objset_close(os);
 	}
@@ -762,11 +812,11 @@ dmu_objset_snapshot_one(char *name, void *arg)
 }
 
 int
-dmu_objset_snapshot(char *fsname, char *snapname, boolean_t recursive)
+dmu_objset_snapshot(char *fsname, char *snapname,
+    nvlist_t *props, boolean_t recursive)
 {
 	dsl_sync_task_t *dst;
-	struct osnode *osn;
-	struct snaparg sn = { 0 };
+	struct snaparg sn;
 	spa_t *spa;
 	int err;
 
@@ -778,8 +828,7 @@ dmu_objset_snapshot(char *fsname, char *snapname, boolean_t recursive)
 
 	sn.dstg = dsl_sync_task_group_create(spa_get_dsl(spa));
 	sn.snapname = snapname;
-	list_create(&sn.objsets, sizeof (struct osnode),
-	    offsetof(struct osnode, node));
+	sn.props = props;
 
 	if (recursive) {
 		sn.checkperms = B_TRUE;
@@ -790,27 +839,19 @@ dmu_objset_snapshot(char *fsname, char *snapname, boolean_t recursive)
 		err = dmu_objset_snapshot_one(fsname, &sn);
 	}
 
-	if (err)
-		goto out;
-
-	err = dsl_sync_task_group_wait(sn.dstg);
+	if (err == 0)
+		err = dsl_sync_task_group_wait(sn.dstg);
 
 	for (dst = list_head(&sn.dstg->dstg_tasks); dst;
 	    dst = list_next(&sn.dstg->dstg_tasks, dst)) {
-		dsl_dataset_t *ds = dst->dst_arg1;
+		objset_t *os = dst->dst_arg1;
+		dsl_dataset_t *ds = os->os->os_dsl_dataset;
 		if (dst->dst_err)
 			dsl_dataset_name(ds, sn.failed);
+		zil_resume(dmu_objset_zil(os));
+		dmu_objset_close(os);
 	}
 
-out:
-	while (osn = list_head(&sn.objsets)) {
-		list_remove(&sn.objsets, osn);
-		zil_resume(dmu_objset_zil(osn->os));
-		dmu_objset_close(osn->os);
-		kmem_free(osn, sizeof (struct osnode));
-	}
-	list_destroy(&sn.objsets);
-
 	if (err)
 		(void) strcpy(fsname, sn.failed);
 	dsl_sync_task_group_destroy(sn.dstg);
@@ -819,7 +860,7 @@ out:
 }
 
 static void
-dmu_objset_sync_dnodes(list_t *list, dmu_tx_t *tx)
+dmu_objset_sync_dnodes(list_t *list, list_t *newlist, dmu_tx_t *tx)
 {
 	dnode_t *dn;
 
@@ -827,14 +868,20 @@ dmu_objset_sync_dnodes(list_t *list, dmu_tx_t *tx)
 		ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
 		ASSERT(dn->dn_dbuf->db_data_pending);
 		/*
-		 * Initialize dn_zio outside dnode_sync()
-		 * to accomodate meta-dnode
+		 * Initialize dn_zio outside dnode_sync() because the
+		 * meta-dnode needs to set it ouside dnode_sync().
 		 */
 		dn->dn_zio = dn->dn_dbuf->db_data_pending->dr_zio;
 		ASSERT(dn->dn_zio);
 
 		ASSERT3U(dn->dn_nlevels, <=, DN_MAX_LEVELS);
 		list_remove(list, dn);
+
+		if (newlist) {
+			(void) dnode_add_ref(dn, newlist);
+			list_insert_tail(newlist, dn);
+		}
+
 		dnode_sync(dn, tx);
 	}
 }
@@ -853,9 +900,12 @@ ready(zio_t *zio, arc_buf_t *abuf, void *arg)
 	ASSERT(BP_GET_LEVEL(bp) == 0);
 
 	/*
-	 * Update rootbp fill count.
+	 * Update rootbp fill count: it should be the number of objects
+	 * allocated in the object set (not counting the "special"
+	 * objects that are stored in the objset_phys_t -- the meta
+	 * dnode and user/group accounting objects).
 	 */
-	bp->blk_fill = 1;	/* count the meta-dnode */
+	bp->blk_fill = 0;
 	for (int i = 0; i < dnp->dn_nblkptr; i++)
 		bp->blk_fill += dnp->dn_blkptr[i].blk_fill;
 
@@ -878,6 +928,7 @@ dmu_objset_sync(objset_impl_t *os, zio_t *pio, dmu_tx_t *tx)
 	writeprops_t wp = { 0 };
 	zio_t *zio;
 	list_t *list;
+	list_t *newlist = NULL;
 	dbuf_dirty_record_t *dr;
 
 	dprintf_ds(os->os_dsl_dataset, "txg=%llu\n", tx->tx_txg);
@@ -915,20 +966,41 @@ dmu_objset_sync(objset_impl_t *os, zio_t *pio, dmu_tx_t *tx)
 	}
 
 	arc_release(os->os_phys_buf, &os->os_phys_buf);
+
 	zio = arc_write(pio, os->os_spa, &wp, DMU_OS_IS_L2CACHEABLE(os),
 	    tx->tx_txg, os->os_rootbp, os->os_phys_buf, ready, NULL, os,
 	    ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_MUSTSUCCEED, &zb);
 
 	/*
-	 * Sync meta-dnode - the parent IO for the sync is the root block
+	 * Sync special dnodes - the parent IO for the sync is the root block
 	 */
 	os->os_meta_dnode->dn_zio = zio;
 	dnode_sync(os->os_meta_dnode, tx);
 
+	os->os_phys->os_flags = os->os_flags;
+
+	if (os->os_userused_dnode &&
+	    os->os_userused_dnode->dn_type != DMU_OT_NONE) {
+		os->os_userused_dnode->dn_zio = zio;
+		dnode_sync(os->os_userused_dnode, tx);
+		os->os_groupused_dnode->dn_zio = zio;
+		dnode_sync(os->os_groupused_dnode, tx);
+	}
+
 	txgoff = tx->tx_txg & TXG_MASK;
 
-	dmu_objset_sync_dnodes(&os->os_free_dnodes[txgoff], tx);
-	dmu_objset_sync_dnodes(&os->os_dirty_dnodes[txgoff], tx);
+	if (dmu_objset_userused_enabled(os)) {
+		newlist = &os->os_synced_dnodes;
+		/*
+		 * We must create the list here because it uses the
+		 * dn_dirty_link[] of this txg.
+		 */
+		list_create(newlist, sizeof (dnode_t),
+		    offsetof(dnode_t, dn_dirty_link[txgoff]));
+	}
+
+	dmu_objset_sync_dnodes(&os->os_free_dnodes[txgoff], newlist, tx);
+	dmu_objset_sync_dnodes(&os->os_dirty_dnodes[txgoff], newlist, tx);
 
 	list = &os->os_meta_dnode->dn_dirty_records[txgoff];
 	while (dr = list_head(list)) {
@@ -945,6 +1017,145 @@ dmu_objset_sync(objset_impl_t *os, zio_t *pio, dmu_tx_t *tx)
 	zio_nowait(zio);
 }
 
+static objset_used_cb_t *used_cbs[DMU_OST_NUMTYPES];
+
+void
+dmu_objset_register_type(dmu_objset_type_t ost, objset_used_cb_t *cb)
+{
+	used_cbs[ost] = cb;
+}
+
+boolean_t
+dmu_objset_userused_enabled(objset_impl_t *os)
+{
+	return (spa_version(os->os_spa) >= SPA_VERSION_USERSPACE &&
+	    used_cbs[os->os_phys->os_type] &&
+	    os->os_userused_dnode);
+}
+
+void
+dmu_objset_do_userquota_callbacks(objset_impl_t *os, dmu_tx_t *tx)
+{
+	dnode_t *dn;
+	list_t *list = &os->os_synced_dnodes;
+	static const char zerobuf[DN_MAX_BONUSLEN] = {0};
+
+	ASSERT(list_head(list) == NULL || dmu_objset_userused_enabled(os));
+
+	while (dn = list_head(list)) {
+		dmu_object_type_t bonustype;
+
+		ASSERT(!DMU_OBJECT_IS_SPECIAL(dn->dn_object));
+		ASSERT(dn->dn_oldphys);
+		ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE ||
+		    dn->dn_phys->dn_flags &
+		    DNODE_FLAG_USERUSED_ACCOUNTED);
+
+		/* Allocate the user/groupused objects if necessary. */
+		if (os->os_userused_dnode->dn_type == DMU_OT_NONE) {
+			VERIFY(0 == zap_create_claim(&os->os,
+			    DMU_USERUSED_OBJECT,
+			    DMU_OT_USERGROUP_USED, DMU_OT_NONE, 0, tx));
+			VERIFY(0 == zap_create_claim(&os->os,
+			    DMU_GROUPUSED_OBJECT,
+			    DMU_OT_USERGROUP_USED, DMU_OT_NONE, 0, tx));
+		}
+
+		/*
+		 * If the object was not previously
+		 * accounted, pretend that it was free.
+		 */
+		if (!(dn->dn_oldphys->dn_flags &
+		    DNODE_FLAG_USERUSED_ACCOUNTED)) {
+			bzero(dn->dn_oldphys, sizeof (dnode_phys_t));
+		}
+
+		/*
+		 * If the object was freed, use the previous bonustype.
+		 */
+		bonustype = dn->dn_phys->dn_bonustype ?
+		    dn->dn_phys->dn_bonustype : dn->dn_oldphys->dn_bonustype;
+		ASSERT(dn->dn_phys->dn_type != 0 ||
+		    (bcmp(DN_BONUS(dn->dn_phys), zerobuf,
+		    DN_MAX_BONUSLEN) == 0 &&
+		    DN_USED_BYTES(dn->dn_phys) == 0));
+		ASSERT(dn->dn_oldphys->dn_type != 0 ||
+		    (bcmp(DN_BONUS(dn->dn_oldphys), zerobuf,
+		    DN_MAX_BONUSLEN) == 0 &&
+		    DN_USED_BYTES(dn->dn_oldphys) == 0));
+		used_cbs[os->os_phys->os_type](&os->os, bonustype,
+		    DN_BONUS(dn->dn_oldphys), DN_BONUS(dn->dn_phys),
+		    DN_USED_BYTES(dn->dn_oldphys),
+		    DN_USED_BYTES(dn->dn_phys), tx);
+
+		/*
+		 * The mutex is needed here for interlock with dnode_allocate.
+		 */
+		mutex_enter(&dn->dn_mtx);
+		zio_buf_free(dn->dn_oldphys, sizeof (dnode_phys_t));
+		dn->dn_oldphys = NULL;
+		mutex_exit(&dn->dn_mtx);
+
+		list_remove(list, dn);
+		dnode_rele(dn, list);
+	}
+}
+
+boolean_t
+dmu_objset_userspace_present(objset_t *os)
+{
+	return (os->os->os_phys->os_flags &
+	    OBJSET_FLAG_USERACCOUNTING_COMPLETE);
+}
+
+int
+dmu_objset_userspace_upgrade(objset_t *os)
+{
+	uint64_t obj;
+	int err = 0;
+
+	if (dmu_objset_userspace_present(os))
+		return (0);
+	if (!dmu_objset_userused_enabled(os->os))
+		return (ENOTSUP);
+	if (dmu_objset_is_snapshot(os))
+		return (EINVAL);
+
+	/*
+	 * We simply need to mark every object dirty, so that it will be
+	 * synced out and now accounted.  If this is called
+	 * concurrently, or if we already did some work before crashing,
+	 * that's fine, since we track each object's accounted state
+	 * independently.
+	 */
+
+	for (obj = 0; err == 0; err = dmu_object_next(os, &obj, FALSE, 0)) {
+		dmu_tx_t *tx = dmu_tx_create(os);
+		dmu_buf_t *db;
+		int objerr;
+
+		if (issig(JUSTLOOKING) && issig(FORREAL))
+			return (EINTR);
+
+		objerr = dmu_bonus_hold(os, obj, FTAG, &db);
+		if (objerr)
+			continue;
+		dmu_tx_hold_bonus(tx, obj);
+		objerr = dmu_tx_assign(tx, TXG_WAIT);
+		if (objerr) {
+			dmu_tx_abort(tx);
+			continue;
+		}
+		dmu_buf_will_dirty(db, tx);
+		dmu_buf_rele(db, FTAG);
+		dmu_tx_commit(tx);
+	}
+
+	os->os->os_flags |= OBJSET_FLAG_USERACCOUNTING_COMPLETE;
+	txg_wait_synced(dmu_objset_pool(os), 0);
+	return (0);
+}
+
 void
 dmu_objset_space(objset_t *os, uint64_t *refdbytesp, uint64_t *availbytesp,
     uint64_t *usedobjsp, uint64_t *availobjsp)
@@ -978,6 +1189,8 @@ dmu_objset_stats(objset_t *os, nvlist_t *nv)
 
 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_TYPE,
 	    os->os->os_phys->os_type);
+	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USERACCOUNTING,
+	    dmu_objset_userspace_present(os));
 }
 
 int
diff --git a/module/zfs/dmu_send.c b/module/zfs/dmu_send.c
index 6043df0aa..9ca3999dd 100644
--- a/module/zfs/dmu_send.c
+++ b/module/zfs/dmu_send.c
@@ -161,7 +161,9 @@ backup_cb(spa_t *spa, blkptr_t *bp, const zbookmark_t *zb,
 	if (issig(JUSTLOOKING) && issig(FORREAL))
 		return (EINTR);
 
-	if (bp == NULL && zb->zb_object == 0) {
+	if (zb->zb_object != 0 && DMU_OBJECT_IS_SPECIAL(zb->zb_object)) {
+		return (0);
+	} else if (bp == NULL && zb->zb_object == 0) {
 		uint64_t span = BP_SPAN(dnp, zb->zb_level);
 		uint64_t dnobj = (zb->zb_blkid * span) >> DNODE_SHIFT;
 		err = dump_freeobjects(ba, dnobj, span >> DNODE_SHIFT);
@@ -775,11 +777,6 @@ restore_object(struct restorearg *ra, objset_t *os, struct drr_object *drro)
 	dmu_tx_t *tx;
 	void *data = NULL;
 
-	err = dmu_object_info(os, drro->drr_object, NULL);
-
-	if (err != 0 && err != ENOENT)
-		return (EINVAL);
-
 	if (drro->drr_type == DMU_OT_NONE ||
 	    drro->drr_type >= DMU_OT_NUMTYPES ||
 	    drro->drr_bonustype >= DMU_OT_NUMTYPES ||
@@ -792,18 +789,21 @@ restore_object(struct restorearg *ra, objset_t *os, struct drr_object *drro)
 		return (EINVAL);
 	}
 
+	err = dmu_object_info(os, drro->drr_object, NULL);
+
+	if (err != 0 && err != ENOENT)
+		return (EINVAL);
+
 	if (drro->drr_bonuslen) {
 		data = restore_read(ra, P2ROUNDUP(drro->drr_bonuslen, 8));
 		if (ra->err)
 			return (ra->err);
 	}
 
-	tx = dmu_tx_create(os);
-
 	if (err == ENOENT) {
 		/* currently free, want to be allocated */
+		tx = dmu_tx_create(os);
 		dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
-		dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0, 1);
 		err = dmu_tx_assign(tx, TXG_WAIT);
 		if (err) {
 			dmu_tx_abort(tx);
@@ -812,28 +812,22 @@ restore_object(struct restorearg *ra, objset_t *os, struct drr_object *drro)
 		err = dmu_object_claim(os, drro->drr_object,
 		    drro->drr_type, drro->drr_blksz,
 		    drro->drr_bonustype, drro->drr_bonuslen, tx);
+		dmu_tx_commit(tx);
 	} else {
 		/* currently allocated, want to be allocated */
-		dmu_tx_hold_bonus(tx, drro->drr_object);
-		/*
-		 * We may change blocksize and delete old content,
-		 * so need to hold_write and hold_free.
-		 */
-		dmu_tx_hold_write(tx, drro->drr_object, 0, 1);
-		dmu_tx_hold_free(tx, drro->drr_object, 0, DMU_OBJECT_END);
-		err = dmu_tx_assign(tx, TXG_WAIT);
-		if (err) {
-			dmu_tx_abort(tx);
-			return (err);
-		}
-
 		err = dmu_object_reclaim(os, drro->drr_object,
 		    drro->drr_type, drro->drr_blksz,
-		    drro->drr_bonustype, drro->drr_bonuslen, tx);
+		    drro->drr_bonustype, drro->drr_bonuslen);
 	}
-	if (err) {
-		dmu_tx_commit(tx);
+	if (err)
 		return (EINVAL);
+
+	tx = dmu_tx_create(os);
+	dmu_tx_hold_bonus(tx, drro->drr_object);
+	err = dmu_tx_assign(tx, TXG_WAIT);
+	if (err) {
+		dmu_tx_abort(tx);
+		return (err);
 	}
 
 	dmu_object_set_checksum(os, drro->drr_object, drro->drr_checksum, tx);
diff --git a/module/zfs/dmu_traverse.c b/module/zfs/dmu_traverse.c
index 197284e1e..89cbfad29 100644
--- a/module/zfs/dmu_traverse.c
+++ b/module/zfs/dmu_traverse.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -64,6 +64,9 @@ struct traverse_data {
 	void *td_arg;
 };
 
+static int traverse_dnode(struct traverse_data *td, const dnode_phys_t *dnp,
+    arc_buf_t *buf, uint64_t objset, uint64_t object);
+
 /* ARGSUSED */
 static void
 traverse_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
@@ -189,7 +192,7 @@ traverse_visitbp(struct traverse_data *td, const dnode_phys_t *dnp,
 		}
 	} else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
 		uint32_t flags = ARC_WAIT;
-		int i, j;
+		int i;
 		int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
 
 		err = arc_read(NULL, td->td_spa, bp, pbuf,
@@ -201,20 +204,15 @@ traverse_visitbp(struct traverse_data *td, const dnode_phys_t *dnp,
 		/* recursively visitbp() blocks below this */
 		dnp = buf->b_data;
 		for (i = 0; i < epb && err == 0; i++, dnp++) {
-			for (j = 0; j < dnp->dn_nblkptr; j++) {
-				SET_BOOKMARK(&czb, zb->zb_objset,
-				    zb->zb_blkid * epb + i,
-				    dnp->dn_nlevels - 1, j);
-				err = traverse_visitbp(td, dnp, buf,
-				    (blkptr_t *)&dnp->dn_blkptr[j], &czb);
-				if (err)
-					break;
-			}
+			err = traverse_dnode(td, dnp, buf, zb->zb_objset,
+			    zb->zb_blkid * epb + i);
+			if (err)
+				break;
 		}
 	} else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
 		uint32_t flags = ARC_WAIT;
 		objset_phys_t *osp;
-		int j;
+		dnode_phys_t *dnp;
 
 		err = arc_read_nolock(NULL, td->td_spa, bp,
 		    arc_getbuf_func, &buf,
@@ -223,20 +221,19 @@ traverse_visitbp(struct traverse_data *td, const dnode_phys_t *dnp,
 			return (err);
 
 		osp = buf->b_data;
-		/*
-		 * traverse_zil is just here for zdb's leak checking.
-		 * For other consumers, there will be no ZIL blocks.
-		 */
 		traverse_zil(td, &osp->os_zil_header);
 
-		for (j = 0; j < osp->os_meta_dnode.dn_nblkptr; j++) {
-			SET_BOOKMARK(&czb, zb->zb_objset, 0,
-			    osp->os_meta_dnode.dn_nlevels - 1, j);
-			err = traverse_visitbp(td, &osp->os_meta_dnode, buf,
-			    (blkptr_t *)&osp->os_meta_dnode.dn_blkptr[j],
-			    &czb);
-			if (err)
-				break;
+		dnp = &osp->os_meta_dnode;
+		err = traverse_dnode(td, dnp, buf, zb->zb_objset, 0);
+		if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) {
+			dnp = &osp->os_userused_dnode;
+			err = traverse_dnode(td, dnp, buf, zb->zb_objset,
+			    DMU_USERUSED_OBJECT);
+		}
+		if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) {
+			dnp = &osp->os_groupused_dnode;
+			err = traverse_dnode(td, dnp, buf, zb->zb_objset,
+			    DMU_GROUPUSED_OBJECT);
 		}
 	}
 
@@ -249,6 +246,23 @@ traverse_visitbp(struct traverse_data *td, const dnode_phys_t *dnp,
 	return (err);
 }
 
+static int
+traverse_dnode(struct traverse_data *td, const dnode_phys_t *dnp,
+    arc_buf_t *buf, uint64_t objset, uint64_t object)
+{
+	int j, err = 0;
+	zbookmark_t czb;
+
+	for (j = 0; j < dnp->dn_nblkptr; j++) {
+		SET_BOOKMARK(&czb, objset, object, dnp->dn_nlevels - 1, j);
+		err = traverse_visitbp(td, dnp, buf,
+		    (blkptr_t *)&dnp->dn_blkptr[j], &czb);
+		if (err)
+			break;
+	}
+	return (err);
+}
+
 /* ARGSUSED */
 static int
 traverse_prefetcher(spa_t *spa, blkptr_t *bp, const zbookmark_t *zb,
diff --git a/module/zfs/dmu_tx.c b/module/zfs/dmu_tx.c
index bf560e565..af2b049a7 100644
--- a/module/zfs/dmu_tx.c
+++ b/module/zfs/dmu_tx.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -160,6 +160,41 @@ dmu_tx_check_ioerr(zio_t *zio, dnode_t *dn, int level, uint64_t blkid)
 	return (err);
 }
 
+static void
+dmu_tx_count_indirects(dmu_tx_hold_t *txh, dmu_buf_impl_t *db,
+    boolean_t freeable, dmu_buf_impl_t **history)
+{
+	int i = db->db_level + 1;
+	dnode_t *dn = db->db_dnode;
+
+	if (i >= dn->dn_nlevels)
+		return;
+
+	db = db->db_parent;
+	if (db == NULL) {
+		uint64_t lvls = dn->dn_nlevels - i;
+
+		txh->txh_space_towrite += lvls << dn->dn_indblkshift;
+		return;
+	}
+
+	if (db != history[i]) {
+		dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
+		uint64_t space = 1ULL << dn->dn_indblkshift;
+
+		freeable = (db->db_blkptr && (freeable ||
+		    dsl_dataset_block_freeable(ds, db->db_blkptr->blk_birth)));
+		if (freeable)
+			txh->txh_space_tooverwrite += space;
+		else
+			txh->txh_space_towrite += space;
+		if (db->db_blkptr)
+			txh->txh_space_tounref += space;
+		history[i] = db;
+		dmu_tx_count_indirects(txh, db, freeable, history);
+	}
+}
+
 /* ARGSUSED */
 static void
 dmu_tx_count_write(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
@@ -177,18 +212,24 @@ dmu_tx_count_write(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
 	min_ibs = DN_MIN_INDBLKSHIFT;
 	max_ibs = DN_MAX_INDBLKSHIFT;
 
-	/*
-	 * For i/o error checking, read the first and last level-0
-	 * blocks (if they are not aligned), and all the level-1 blocks.
-	 */
-
 	if (dn) {
+		dmu_buf_impl_t *last[DN_MAX_LEVELS];
+		int nlvls = dn->dn_nlevels;
+		int delta;
+
+		/*
+		 * For i/o error checking, read the first and last level-0
+		 * blocks (if they are not aligned), and all the level-1 blocks.
+		 */
 		if (dn->dn_maxblkid == 0) {
-			if ((off > 0 || len < dn->dn_datablksz) &&
-			    off < dn->dn_datablksz) {
+			delta = dn->dn_datablksz;
+			start = (off < dn->dn_datablksz) ? 0 : 1;
+			end = (off+len <= dn->dn_datablksz) ? 0 : 1;
+			if (start == 0 && (off > 0 || len < dn->dn_datablksz)) {
 				err = dmu_tx_check_ioerr(NULL, dn, 0, 0);
 				if (err)
 					goto out;
+				delta -= off;
 			}
 		} else {
 			zio_t *zio = zio_root(dn->dn_objset->os_spa,
@@ -213,10 +254,9 @@ dmu_tx_count_write(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
 			}
 
 			/* level-1 blocks */
-			if (dn->dn_nlevels > 1) {
-				start >>= dn->dn_indblkshift - SPA_BLKPTRSHIFT;
-				end >>= dn->dn_indblkshift - SPA_BLKPTRSHIFT;
-				for (i = start+1; i < end; i++) {
+			if (nlvls > 1) {
+				int shft = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
+				for (i = (start>>shft)+1; i < end>>shft; i++) {
 					err = dmu_tx_check_ioerr(zio, dn, 1, i);
 					if (err)
 						goto out;
@@ -226,20 +266,70 @@ dmu_tx_count_write(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
 			err = zio_wait(zio);
 			if (err)
 				goto out;
+			delta = P2NPHASE(off, dn->dn_datablksz);
 		}
-	}
 
-	/*
-	 * If there's more than one block, the blocksize can't change,
-	 * so we can make a more precise estimate.  Alternatively,
-	 * if the dnode's ibs is larger than max_ibs, always use that.
-	 * This ensures that if we reduce DN_MAX_INDBLKSHIFT,
-	 * the code will still work correctly on existing pools.
-	 */
-	if (dn && (dn->dn_maxblkid != 0 || dn->dn_indblkshift > max_ibs)) {
-		min_ibs = max_ibs = dn->dn_indblkshift;
-		if (dn->dn_datablkshift != 0)
+		if (dn->dn_maxblkid > 0) {
+			/*
+			 * The blocksize can't change,
+			 * so we can make a more precise estimate.
+			 */
+			ASSERT(dn->dn_datablkshift != 0);
 			min_bs = max_bs = dn->dn_datablkshift;
+			min_ibs = max_ibs = dn->dn_indblkshift;
+		} else if (dn->dn_indblkshift > max_ibs) {
+			/*
+			 * This ensures that if we reduce DN_MAX_INDBLKSHIFT,
+			 * the code will still work correctly on older pools.
+			 */
+			min_ibs = max_ibs = dn->dn_indblkshift;
+		}
+
+		/*
+		 * If this write is not off the end of the file
+		 * we need to account for overwrites/unref.
+		 */
+		if (start <= dn->dn_maxblkid)
+			bzero(last, sizeof (dmu_buf_impl_t *) * DN_MAX_LEVELS);
+		while (start <= dn->dn_maxblkid) {
+			spa_t *spa = txh->txh_tx->tx_pool->dp_spa;
+			dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset;
+			dmu_buf_impl_t *db;
+
+			rw_enter(&dn->dn_struct_rwlock, RW_READER);
+			db = dbuf_hold_level(dn, 0, start, FTAG);
+			rw_exit(&dn->dn_struct_rwlock);
+			if (db->db_blkptr && dsl_dataset_block_freeable(ds,
+			    db->db_blkptr->blk_birth)) {
+				dprintf_bp(db->db_blkptr, "can free old%s", "");
+				txh->txh_space_tooverwrite += dn->dn_datablksz;
+				txh->txh_space_tounref += dn->dn_datablksz;
+				dmu_tx_count_indirects(txh, db, TRUE, last);
+			} else {
+				txh->txh_space_towrite += dn->dn_datablksz;
+				if (db->db_blkptr)
+					txh->txh_space_tounref +=
+					    bp_get_dasize(spa, db->db_blkptr);
+				dmu_tx_count_indirects(txh, db, FALSE, last);
+			}
+			dbuf_rele(db, FTAG);
+			if (++start > end) {
+				/*
+				 * Account for new indirects appearing
+				 * before this IO gets assigned into a txg.
+				 */
+				bits = 64 - min_bs;
+				epbs = min_ibs - SPA_BLKPTRSHIFT;
+				for (bits -= epbs * (nlvls - 1);
+				    bits >= 0; bits -= epbs)
+					txh->txh_fudge += 1ULL << max_ibs;
+				goto out;
+			}
+			off += delta;
+			if (len >= delta)
+				len -= delta;
+			delta = dn->dn_datablksz;
+		}
 	}
 
 	/*
@@ -262,20 +352,22 @@ dmu_tx_count_write(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
 	for (bits = 64 - min_bs; bits >= 0; bits -= epbs) {
 		start >>= epbs;
 		end >>= epbs;
-		/*
-		 * If we increase the number of levels of indirection,
-		 * we'll need new blkid=0 indirect blocks.  If start == 0,
-		 * we're already accounting for that blocks; and if end == 0,
-		 * we can't increase the number of levels beyond that.
-		 */
-		if (start != 0 && end != 0)
-			txh->txh_space_towrite += 1ULL << max_ibs;
+		ASSERT3U(end, >=, start);
 		txh->txh_space_towrite += (end - start + 1) << max_ibs;
+		if (start != 0) {
+			/*
+			 * We also need a new blkid=0 indirect block
+			 * to reference any existing file data.
+			 */
+			txh->txh_space_towrite += 1ULL << max_ibs;
+		}
 	}
 
-	ASSERT(txh->txh_space_towrite < 2 * DMU_MAX_ACCESS);
-
 out:
+	if (txh->txh_space_towrite + txh->txh_space_tooverwrite >
+	    2 * DMU_MAX_ACCESS)
+		err = EFBIG;
+
 	if (err)
 		txh->txh_tx->tx_err = err;
 }
@@ -292,6 +384,7 @@ dmu_tx_count_dnode(dmu_tx_hold_t *txh)
 	    dsl_dataset_block_freeable(dn->dn_objset->os_dsl_dataset,
 	    dn->dn_dbuf->db_blkptr->blk_birth)) {
 		txh->txh_space_tooverwrite += space;
+		txh->txh_space_tounref += space;
 	} else {
 		txh->txh_space_towrite += space;
 		if (dn && dn->dn_dbuf->db_blkptr)
@@ -535,7 +628,7 @@ dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off, uint64_t len)
 }
 
 void
-dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, char *name)
+dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, const char *name)
 {
 	dmu_tx_hold_t *txh;
 	dnode_t *dn;
@@ -584,9 +677,9 @@ dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, char *name)
 			txh->txh_space_tooverwrite += SPA_MAXBLOCKSIZE;
 		} else {
 			txh->txh_space_towrite += SPA_MAXBLOCKSIZE;
-			txh->txh_space_tounref +=
-			    BP_GET_ASIZE(dn->dn_phys->dn_blkptr);
 		}
+		if (dn->dn_phys->dn_blkptr[0].blk_birth)
+			txh->txh_space_tounref += SPA_MAXBLOCKSIZE;
 		return;
 	}
 
@@ -603,12 +696,9 @@ dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, char *name)
 		}
 	}
 
-	/*
-	 * 3 blocks overwritten: target leaf, ptrtbl block, header block
-	 * 3 new blocks written if adding: new split leaf, 2 grown ptrtbl blocks
-	 */
-	dmu_tx_count_write(txh, dn->dn_maxblkid * dn->dn_datablksz,
-	    (3 + (add ? 3 : 0)) << dn->dn_datablkshift);
+	err = zap_count_write(&dn->dn_objset->os, dn->dn_object, name, add,
+	    &txh->txh_space_towrite, &txh->txh_space_tooverwrite,
+	    txh->txh_dnode->dn_datablkshift);
 
 	/*
 	 * If the modified blocks are scattered to the four winds,
@@ -616,7 +706,10 @@ dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, char *name)
 	 */
 	epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
 	for (nblocks = dn->dn_maxblkid >> epbs; nblocks != 0; nblocks >>= epbs)
-		txh->txh_space_towrite += 3 << dn->dn_indblkshift;
+		if (dn->dn_objset->os_dsl_dataset->ds_phys->ds_prev_snap_obj)
+			txh->txh_space_towrite += 3 << dn->dn_indblkshift;
+		else
+			txh->txh_space_tooverwrite += 3 << dn->dn_indblkshift;
 }
 
 void
diff --git a/module/zfs/dnode.c b/module/zfs/dnode.c
index 538a141b0..cf49b97f1 100644
--- a/module/zfs/dnode.c
+++ b/module/zfs/dnode.c
@@ -156,7 +156,7 @@ dnode_verify(dnode_t *dn)
 	}
 	if (dn->dn_phys->dn_type != DMU_OT_NONE)
 		ASSERT3U(dn->dn_phys->dn_nlevels, <=, dn->dn_nlevels);
-	ASSERT(dn->dn_object == DMU_META_DNODE_OBJECT || dn->dn_dbuf != NULL);
+	ASSERT(DMU_OBJECT_IS_SPECIAL(dn->dn_object) || dn->dn_dbuf != NULL);
 	if (dn->dn_dbuf != NULL) {
 		ASSERT3P(dn->dn_phys, ==,
 		    (dnode_phys_t *)dn->dn_dbuf->db.db_data +
@@ -321,6 +321,7 @@ dnode_destroy(dnode_t *dn)
 	}
 	ASSERT(NULL == list_head(&dn->dn_dbufs));
 #endif
+	ASSERT(dn->dn_oldphys == NULL);
 
 	mutex_enter(&os->os_lock);
 	list_remove(&os->os_dnodes, dn);
@@ -417,8 +418,7 @@ void
 dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize,
     dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx)
 {
-	int i, nblkptr;
-	dmu_buf_impl_t *db = NULL;
+	int nblkptr;
 
 	ASSERT3U(blocksize, >=, SPA_MINBLOCKSIZE);
 	ASSERT3U(blocksize, <=, SPA_MAXBLOCKSIZE);
@@ -430,42 +430,25 @@ dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize,
 	ASSERT3U(bonustype, <, DMU_OT_NUMTYPES);
 	ASSERT3U(bonuslen, <=, DN_MAX_BONUSLEN);
 
-	for (i = 0; i < TXG_SIZE; i++)
-		ASSERT(!list_link_active(&dn->dn_dirty_link[i]));
-
 	/* clean up any unreferenced dbufs */
 	dnode_evict_dbufs(dn);
-	ASSERT3P(list_head(&dn->dn_dbufs), ==, NULL);
-
-	/*
-	 * XXX I should really have a generation number to tell if we
-	 * need to do this...
-	 */
-	if (blocksize != dn->dn_datablksz ||
-	    dn->dn_bonustype != bonustype || dn->dn_bonuslen != bonuslen) {
-		/* free all old data */
-		dnode_free_range(dn, 0, -1ULL, tx);
-	}
-
-	nblkptr = 1 + ((DN_MAX_BONUSLEN - bonuslen) >> SPA_BLKPTRSHIFT);
 
-	/* change blocksize */
 	rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
-	if (blocksize != dn->dn_datablksz &&
-	    (!BP_IS_HOLE(&dn->dn_phys->dn_blkptr[0]) ||
-	    list_head(&dn->dn_dbufs) != NULL)) {
-		db = dbuf_hold(dn, 0, FTAG);
-		dbuf_new_size(db, blocksize, tx);
-	}
-	dnode_setdblksz(dn, blocksize);
 	dnode_setdirty(dn, tx);
-	dn->dn_next_bonuslen[tx->tx_txg&TXG_MASK] = bonuslen;
-	dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = blocksize;
+	if (dn->dn_datablksz != blocksize) {
+		/* change blocksize */
+		ASSERT(dn->dn_maxblkid == 0 &&
+		    (BP_IS_HOLE(&dn->dn_phys->dn_blkptr[0]) ||
+		    dnode_block_freed(dn, 0)));
+		dnode_setdblksz(dn, blocksize);
+		dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = blocksize;
+	}
+	if (dn->dn_bonuslen != bonuslen)
+		dn->dn_next_bonuslen[tx->tx_txg&TXG_MASK] = bonuslen;
+	nblkptr = 1 + ((DN_MAX_BONUSLEN - bonuslen) >> SPA_BLKPTRSHIFT);
 	if (dn->dn_nblkptr != nblkptr)
 		dn->dn_next_nblkptr[tx->tx_txg&TXG_MASK] = nblkptr;
 	rw_exit(&dn->dn_struct_rwlock);
-	if (db)
-		dbuf_rele(db, FTAG);
 
 	/* change type */
 	dn->dn_type = ot;
@@ -569,6 +552,22 @@ dnode_hold_impl(objset_impl_t *os, uint64_t object, int flag,
 	 */
 	ASSERT(spa_config_held(os->os_spa, SCL_ALL, RW_WRITER) == 0);
 
+	if (object == DMU_USERUSED_OBJECT || object == DMU_GROUPUSED_OBJECT) {
+		dn = (object == DMU_USERUSED_OBJECT) ?
+		    os->os_userused_dnode : os->os_groupused_dnode;
+		if (dn == NULL)
+			return (ENOENT);
+		type = dn->dn_type;
+		if ((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE)
+			return (ENOENT);
+		if ((flag & DNODE_MUST_BE_FREE) && type != DMU_OT_NONE)
+			return (EEXIST);
+		DNODE_VERIFY(dn);
+		(void) refcount_add(&dn->dn_holds, tag);
+		*dnp = dn;
+		return (0);
+	}
+
 	if (object == 0 || object >= DN_MAX_OBJECT)
 		return (EINVAL);
 
@@ -627,7 +626,8 @@ dnode_hold_impl(objset_impl_t *os, uint64_t object, int flag,
 	type = dn->dn_type;
 	if (dn->dn_free_txg ||
 	    ((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE) ||
-	    ((flag & DNODE_MUST_BE_FREE) && type != DMU_OT_NONE)) {
+	    ((flag & DNODE_MUST_BE_FREE) &&
+	    (type != DMU_OT_NONE || dn->dn_oldphys))) {
 		mutex_exit(&dn->dn_mtx);
 		dbuf_rele(db, FTAG);
 		return (type == DMU_OT_NONE ? ENOENT : EEXIST);
@@ -692,8 +692,10 @@ dnode_setdirty(dnode_t *dn, dmu_tx_t *tx)
 	objset_impl_t *os = dn->dn_objset;
 	uint64_t txg = tx->tx_txg;
 
-	if (dn->dn_object == DMU_META_DNODE_OBJECT)
+	if (DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
+		dsl_dataset_dirty(os->os_dsl_dataset, tx);
 		return;
+	}
 
 	DNODE_VERIFY(dn);
 
@@ -1189,11 +1191,6 @@ dnode_block_freed(dnode_t *dn, uint64_t blkid)
 	if (dn->dn_free_txg)
 		return (TRUE);
 
-	/*
-	 * If dn_datablkshift is not set, then there's only a single
-	 * block, in which case there will never be a free range so it
-	 * won't matter.
-	 */
 	range_tofind.fr_blkid = blkid;
 	mutex_enter(&dn->dn_mtx);
 	for (i = 0; i < TXG_SIZE; i++) {
@@ -1278,7 +1275,7 @@ dnode_next_offset_level(dnode_t *dn, int flags, uint64_t *offset,
 	dprintf("probing object %llu offset %llx level %d of %u\n",
 	    dn->dn_object, *offset, lvl, dn->dn_phys->dn_nlevels);
 
-	hole = flags & DNODE_FIND_HOLE;
+	hole = ((flags & DNODE_FIND_HOLE) != 0);
 	inc = (flags & DNODE_FIND_BACKWARDS) ? -1 : 1;
 	ASSERT(txg == 0 || !hole);
 
@@ -1325,16 +1322,7 @@ dnode_next_offset_level(dnode_t *dn, int flags, uint64_t *offset,
 
 		for (i = (*offset >> span) & (blkfill - 1);
 		    i >= 0 && i < blkfill; i += inc) {
-			boolean_t newcontents = B_TRUE;
-			if (txg) {
-				int j;
-				newcontents = B_FALSE;
-				for (j = 0; j < dnp[i].dn_nblkptr; j++) {
-					if (dnp[i].dn_blkptr[j].blk_birth > txg)
-						newcontents = B_TRUE;
-				}
-			}
-			if (!dnp[i].dn_type == hole && newcontents)
+			if ((dnp[i].dn_type == DMU_OT_NONE) == hole)
 				break;
 			*offset += (1ULL << span) * inc;
 		}
diff --git a/module/zfs/dnode_sync.c b/module/zfs/dnode_sync.c
index 23dcb4c7b..184fe292b 100644
--- a/module/zfs/dnode_sync.c
+++ b/module/zfs/dnode_sync.c
@@ -504,9 +504,6 @@ dnode_sync_free(dnode_t *dn, dmu_tx_t *tx)
 
 /*
  * Write out the dnode's dirty buffers.
- *
- * NOTE: The dnode is kept in memory by being dirty.  Once the
- * dirty bit is cleared, it may be evicted.  Beware of this!
  */
 void
 dnode_sync(dnode_t *dn, dmu_tx_t *tx)
@@ -515,20 +512,33 @@ dnode_sync(dnode_t *dn, dmu_tx_t *tx)
 	dnode_phys_t *dnp = dn->dn_phys;
 	int txgoff = tx->tx_txg & TXG_MASK;
 	list_t *list = &dn->dn_dirty_records[txgoff];
+	static const dnode_phys_t zerodn = { 0 };
 
 	ASSERT(dmu_tx_is_syncing(tx));
 	ASSERT(dnp->dn_type != DMU_OT_NONE || dn->dn_allocated_txg);
+	ASSERT(dnp->dn_type != DMU_OT_NONE ||
+	    bcmp(dnp, &zerodn, DNODE_SIZE) == 0);
 	DNODE_VERIFY(dn);
 
 	ASSERT(dn->dn_dbuf == NULL || arc_released(dn->dn_dbuf->db_buf));
 
+	if (dmu_objset_userused_enabled(dn->dn_objset) &&
+	    !DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
+		ASSERT(dn->dn_oldphys == NULL);
+		dn->dn_oldphys = zio_buf_alloc(sizeof (dnode_phys_t));
+		*dn->dn_oldphys = *dn->dn_phys; /* struct assignment */
+		dn->dn_phys->dn_flags |= DNODE_FLAG_USERUSED_ACCOUNTED;
+	} else {
+		/* Once we account for it, we should always account for it. */
+		ASSERT(!(dn->dn_phys->dn_flags &
+		    DNODE_FLAG_USERUSED_ACCOUNTED));
+	}
+
 	mutex_enter(&dn->dn_mtx);
 	if (dn->dn_allocated_txg == tx->tx_txg) {
 		/* The dnode is newly allocated or reallocated */
 		if (dnp->dn_type == DMU_OT_NONE) {
 			/* this is a first alloc, not a realloc */
-			/* XXX shouldn't the phys already be zeroed? */
-			bzero(dnp, DNODE_CORE_SIZE);
 			dnp->dn_nlevels = 1;
 			dnp->dn_nblkptr = dn->dn_nblkptr;
 		}
@@ -626,7 +636,7 @@ dnode_sync(dnode_t *dn, dmu_tx_t *tx)
 
 	dbuf_sync_list(list, tx);
 
-	if (dn->dn_object != DMU_META_DNODE_OBJECT) {
+	if (!DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
 		ASSERT3P(list_head(list), ==, NULL);
 		dnode_rele(dn, (void *)(uintptr_t)tx->tx_txg);
 	}
diff --git a/module/zfs/dsl_dataset.c b/module/zfs/dsl_dataset.c
index a68b12d33..0fe7eb583 100644
--- a/module/zfs/dsl_dataset.c
+++ b/module/zfs/dsl_dataset.c
@@ -229,7 +229,7 @@ dsl_dataset_prev_snap_txg(dsl_dataset_t *ds)
 	return (MAX(ds->ds_phys->ds_prev_snap_txg, trysnap));
 }
 
-int
+boolean_t
 dsl_dataset_block_freeable(dsl_dataset_t *ds, uint64_t blk_birth)
 {
 	return (blk_birth > dsl_dataset_prev_snap_txg(ds));
@@ -548,6 +548,7 @@ dsl_dataset_own_obj(dsl_pool_t *dp, uint64_t dsobj, int flags, void *owner,
 		return (err);
 	if (!dsl_dataset_tryown(*dsp, DS_MODE_IS_INCONSISTENT(flags), owner)) {
 		dsl_dataset_rele(*dsp, owner);
+		*dsp = NULL;
 		return (EBUSY);
 	}
 	return (0);
@@ -974,6 +975,27 @@ dsl_dataset_destroy(dsl_dataset_t *ds, void *tag)
 		(void) dmu_free_object(os, obj);
 	}
 
+	/*
+	 * We need to sync out all in-flight IO before we try to evict
+	 * (the dataset evict func is trying to clear the cached entries
+	 * for this dataset in the ARC).
+	 */
+	txg_wait_synced(dd->dd_pool, 0);
+
+	/*
+	 * If we managed to free all the objects in open
+	 * context, the user space accounting should be zero.
+	 */
+	if (ds->ds_phys->ds_bp.blk_fill == 0 &&
+	    dmu_objset_userused_enabled(os->os)) {
+		uint64_t count;
+
+		ASSERT(zap_count(os, DMU_USERUSED_OBJECT, &count) != 0 ||
+		    count == 0);
+		ASSERT(zap_count(os, DMU_GROUPUSED_OBJECT, &count) != 0 ||
+		    count == 0);
+	}
+
 	dmu_objset_close(os);
 	if (err != ESRCH)
 		goto out;
@@ -1058,7 +1080,6 @@ dsl_dataset_get_user_ptr(dsl_dataset_t *ds)
 	return (ds->ds_user_ptr);
 }
 
-
 blkptr_t *
 dsl_dataset_get_blkptr(dsl_dataset_t *ds)
 {
@@ -1164,8 +1185,18 @@ kill_blkptr(spa_t *spa, blkptr_t *bp, const zbookmark_t *zb,
 	if (bp == NULL)
 		return (0);
 
-	ASSERT3U(bp->blk_birth, >, ka->ds->ds_phys->ds_prev_snap_txg);
-	(void) dsl_dataset_block_kill(ka->ds, bp, ka->zio, ka->tx);
+	if ((zb->zb_level == -1ULL && zb->zb_blkid != 0) ||
+	    (zb->zb_object != 0 && dnp == NULL)) {
+		/*
+		 * It's a block in the intent log.  It has no
+		 * accounting, so just free it.
+		 */
+		VERIFY3U(0, ==, dsl_free(ka->zio, ka->tx->tx_pool,
+		    ka->tx->tx_txg, bp, NULL, NULL, ARC_NOWAIT));
+	} else {
+		ASSERT3U(bp->blk_birth, >, ka->ds->ds_phys->ds_prev_snap_txg);
+		(void) dsl_dataset_block_kill(ka->ds, bp, ka->zio, ka->tx);
+	}
 
 	return (0);
 }
@@ -1209,13 +1240,7 @@ dsl_dataset_rollback_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
 
 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
 
-	/*
-	 * Before the roll back destroy the zil.
-	 */
 	if (ds->ds_user_ptr != NULL) {
-		zil_rollback_destroy(
-		    ((objset_impl_t *)ds->ds_user_ptr)->os_zil, tx);
-
 		/*
 		 * We need to make sure that the objset_impl_t is reopened after
 		 * we do the rollback, otherwise it will have the wrong
@@ -1248,7 +1273,10 @@ dsl_dataset_rollback_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
 	    ds->ds_phys->ds_deadlist_obj));
 
 	{
-		/* Free blkptrs that we gave birth to */
+		/*
+		 * Free blkptrs that we gave birth to - this covers
+		 * claimed but not played log blocks too.
+		 */
 		zio_t *zio;
 		struct killarg ka;
 
@@ -1262,8 +1290,7 @@ dsl_dataset_rollback_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
 		(void) zio_wait(zio);
 	}
 
-	ASSERT(!(ds->ds_phys->ds_flags & DS_FLAG_UNIQUE_ACCURATE) ||
-	    ds->ds_phys->ds_unique_bytes == 0);
+	ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) || ds->ds_phys->ds_unique_bytes == 0);
 
 	if (ds->ds_prev && ds->ds_prev != ds->ds_dir->dd_pool->dp_origin_snap) {
 		/* Change our contents to that of the prev snapshot */
@@ -1481,7 +1508,7 @@ dsl_dataset_destroy_sync(void *arg1, void *tag, cred_t *cr, dmu_tx_t *tx)
 		dmu_buf_will_dirty(ds_prev->ds_dbuf, tx);
 		if (after_branch_point &&
 		    ds_prev->ds_phys->ds_next_clones_obj != 0) {
-			VERIFY(0 == zap_remove_int(mos,
+			VERIFY3U(0, ==, zap_remove_int(mos,
 			    ds_prev->ds_phys->ds_next_clones_obj, obj, tx));
 			if (ds->ds_phys->ds_next_snap_obj != 0) {
 				VERIFY(0 == zap_add_int(mos,
@@ -1654,7 +1681,7 @@ dsl_dataset_destroy_sync(void *arg1, void *tag, cred_t *cr, dmu_tx_t *tx)
 		err = traverse_dataset(ds, ds->ds_phys->ds_prev_snap_txg,
 		    TRAVERSE_POST, kill_blkptr, &ka);
 		ASSERT3U(err, ==, 0);
-		ASSERT(spa_version(dp->dp_spa) < SPA_VERSION_UNIQUE_ACCURATE ||
+		ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
 		    ds->ds_phys->ds_unique_bytes == 0);
 	}
 
@@ -2583,7 +2610,7 @@ snaplist_destroy(list_t *l, boolean_t own)
 {
 	struct promotenode *snap;
 
-	if (!list_link_active(&l->list_head))
+	if (!l || !list_link_active(&l->list_head))
 		return;
 
 	while ((snap = list_tail(l)) != NULL) {
diff --git a/module/zfs/dsl_dir.c b/module/zfs/dsl_dir.c
index e5e18f428..f19653d92 100644
--- a/module/zfs/dsl_dir.c
+++ b/module/zfs/dsl_dir.c
@@ -227,24 +227,11 @@ dsl_dir_namelen(dsl_dir_t *dd)
 	return (result);
 }
 
-int
-dsl_dir_is_private(dsl_dir_t *dd)
-{
-	int rv = FALSE;
-
-	if (dd->dd_parent && dsl_dir_is_private(dd->dd_parent))
-		rv = TRUE;
-	if (dataset_name_hidden(dd->dd_myname))
-		rv = TRUE;
-	return (rv);
-}
-
-
 static int
 getcomponent(const char *path, char *component, const char **nextp)
 {
 	char *p;
-	if (path == NULL)
+	if ((path == NULL) || (path[0] == '\0'))
 		return (ENOENT);
 	/* This would be a good place to reserve some namespace... */
 	p = strpbrk(path, "/@");
diff --git a/module/zfs/dsl_pool.c b/module/zfs/dsl_pool.c
index dacc57c81..2c5dfca53 100644
--- a/module/zfs/dsl_pool.c
+++ b/module/zfs/dsl_pool.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -90,6 +90,9 @@ dsl_pool_open_impl(spa_t *spa, uint64_t txg)
 	mutex_init(&dp->dp_lock, NULL, MUTEX_DEFAULT, NULL);
 	mutex_init(&dp->dp_scrub_cancel_lock, NULL, MUTEX_DEFAULT, NULL);
 
+	dp->dp_vnrele_taskq = taskq_create("zfs_vn_rele_taskq", 1, minclsyspri,
+	    1, 4, 0);
+
 	return (dp);
 }
 
@@ -129,14 +132,15 @@ dsl_pool_open(spa_t *spa, uint64_t txg, dsl_pool_t **dpp)
 			goto out;
 		err = dsl_dataset_hold_obj(dp, dd->dd_phys->dd_head_dataset_obj,
 		    FTAG, &ds);
+		if (err == 0) {
+			err = dsl_dataset_hold_obj(dp,
+			    ds->ds_phys->ds_prev_snap_obj, dp,
+			    &dp->dp_origin_snap);
+			dsl_dataset_rele(ds, FTAG);
+		}
+		dsl_dir_close(dd, dp);
 		if (err)
 			goto out;
-		err = dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
-		    dp, &dp->dp_origin_snap);
-		if (err)
-			goto out;
-		dsl_dataset_rele(ds, FTAG);
-		dsl_dir_close(dd, dp);
 	}
 
 	/* get scrub status */
@@ -226,6 +230,7 @@ dsl_pool_close(dsl_pool_t *dp)
 	rw_destroy(&dp->dp_config_rwlock);
 	mutex_destroy(&dp->dp_lock);
 	mutex_destroy(&dp->dp_scrub_cancel_lock);
+	taskq_destroy(dp->dp_vnrele_taskq);
 	if (dp->dp_blkstats)
 		kmem_free(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
 	kmem_free(dp, sizeof (dsl_pool_t));
@@ -296,24 +301,52 @@ dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
 	tx = dmu_tx_create_assigned(dp, txg);
 
 	dp->dp_read_overhead = 0;
+	start = gethrtime();
+
 	zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
 	while (ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) {
-		if (!list_link_active(&ds->ds_synced_link))
-			list_insert_tail(&dp->dp_synced_datasets, ds);
-		else
-			dmu_buf_rele(ds->ds_dbuf, ds);
+		/*
+		 * We must not sync any non-MOS datasets twice, because
+		 * we may have taken a snapshot of them.  However, we
+		 * may sync newly-created datasets on pass 2.
+		 */
+		ASSERT(!list_link_active(&ds->ds_synced_link));
+		list_insert_tail(&dp->dp_synced_datasets, ds);
 		dsl_dataset_sync(ds, zio, tx);
 	}
 	DTRACE_PROBE(pool_sync__1setup);
-
-	start = gethrtime();
 	err = zio_wait(zio);
+
 	write_time = gethrtime() - start;
 	ASSERT(err == 0);
 	DTRACE_PROBE(pool_sync__2rootzio);
 
-	while (dstg = txg_list_remove(&dp->dp_sync_tasks, txg))
+	for (ds = list_head(&dp->dp_synced_datasets); ds;
+	    ds = list_next(&dp->dp_synced_datasets, ds))
+		dmu_objset_do_userquota_callbacks(ds->ds_user_ptr, tx);
+
+	/*
+	 * Sync the datasets again to push out the changes due to
+	 * userquota updates.  This must be done before we process the
+	 * sync tasks, because that could cause a snapshot of a dataset
+	 * whose ds_bp will be rewritten when we do this 2nd sync.
+	 */
+	zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
+	while (ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) {
+		ASSERT(list_link_active(&ds->ds_synced_link));
+		dmu_buf_rele(ds->ds_dbuf, ds);
+		dsl_dataset_sync(ds, zio, tx);
+	}
+	err = zio_wait(zio);
+
+	while (dstg = txg_list_remove(&dp->dp_sync_tasks, txg)) {
+		/*
+		 * No more sync tasks should have been added while we
+		 * were syncing.
+		 */
+		ASSERT(spa_sync_pass(dp->dp_spa) == 1);
 		dsl_sync_task_group_sync(dstg, tx);
+	}
 	DTRACE_PROBE(pool_sync__3task);
 
 	start = gethrtime();
@@ -611,3 +644,9 @@ dsl_pool_create_origin(dsl_pool_t *dp, dmu_tx_t *tx)
 	dsl_dataset_rele(ds, FTAG);
 	rw_exit(&dp->dp_config_rwlock);
 }
+
+taskq_t *
+dsl_pool_vnrele_taskq(dsl_pool_t *dp)
+{
+	return (dp->dp_vnrele_taskq);
+}
diff --git a/module/zfs/dsl_prop.c b/module/zfs/dsl_prop.c
index 212acbbc5..664ccff45 100644
--- a/module/zfs/dsl_prop.c
+++ b/module/zfs/dsl_prop.c
@@ -19,12 +19,10 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/dmu.h>
 #include <sys/dmu_objset.h>
 #include <sys/dmu_tx.h>
@@ -416,6 +414,34 @@ dsl_prop_set_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
 }
 
 void
+dsl_props_set_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
+{
+	dsl_dataset_t *ds = arg1;
+	nvlist_t *nvl = arg2;
+	nvpair_t *elem = NULL;
+
+	while ((elem = nvlist_next_nvpair(nvl, elem)) != NULL) {
+		struct prop_set_arg psa;
+
+		psa.name = nvpair_name(elem);
+
+		if (nvpair_type(elem) == DATA_TYPE_STRING) {
+			VERIFY(nvpair_value_string(elem,
+			    (char **)&psa.buf) == 0);
+			psa.intsz = 1;
+			psa.numints = strlen(psa.buf) + 1;
+		} else {
+			uint64_t intval;
+			VERIFY(nvpair_value_uint64(elem, &intval) == 0);
+			psa.intsz = sizeof (intval);
+			psa.numints = 1;
+			psa.buf = &intval;
+		}
+		dsl_prop_set_sync(ds, &psa, cr, tx);
+	}
+}
+
+void
 dsl_prop_set_uint64_sync(dsl_dir_t *dd, const char *name, uint64_t val,
     cred_t *cr, dmu_tx_t *tx)
 {
@@ -438,6 +464,7 @@ dsl_prop_set(const char *dsname, const char *propname,
     int intsz, int numints, const void *buf)
 {
 	dsl_dataset_t *ds;
+	uint64_t version;
 	int err;
 	struct prop_set_arg psa;
 
@@ -447,15 +474,19 @@ dsl_prop_set(const char *dsname, const char *propname,
 	 */
 	if (strlen(propname) >= ZAP_MAXNAMELEN)
 		return (ENAMETOOLONG);
-	if (intsz * numints >= ZAP_MAXVALUELEN)
-		return (E2BIG);
 
 	err = dsl_dataset_hold(dsname, FTAG, &ds);
 	if (err)
 		return (err);
 
+	version = spa_version(ds->ds_dir->dd_pool->dp_spa);
+	if (intsz * numints >= (version < SPA_VERSION_STMF_PROP ?
+	    ZAP_OLDMAXVALUELEN : ZAP_MAXVALUELEN)) {
+		dsl_dataset_rele(ds, FTAG);
+		return (E2BIG);
+	}
 	if (dsl_dataset_is_snapshot(ds) &&
-	    spa_version(ds->ds_dir->dd_pool->dp_spa) < SPA_VERSION_SNAP_PROPS) {
+	    version < SPA_VERSION_SNAP_PROPS) {
 		dsl_dataset_rele(ds, FTAG);
 		return (ENOTSUP);
 	}
@@ -471,6 +502,50 @@ dsl_prop_set(const char *dsname, const char *propname,
 	return (err);
 }
 
+int
+dsl_props_set(const char *dsname, nvlist_t *nvl)
+{
+	dsl_dataset_t *ds;
+	uint64_t version;
+	nvpair_t *elem = NULL;
+	int err;
+
+	if (err = dsl_dataset_hold(dsname, FTAG, &ds))
+		return (err);
+	/*
+	 * Do these checks before the syncfunc, since it can't fail.
+	 */
+	version = spa_version(ds->ds_dir->dd_pool->dp_spa);
+	while ((elem = nvlist_next_nvpair(nvl, elem)) != NULL) {
+		if (strlen(nvpair_name(elem)) >= ZAP_MAXNAMELEN) {
+			dsl_dataset_rele(ds, FTAG);
+			return (ENAMETOOLONG);
+		}
+		if (nvpair_type(elem) == DATA_TYPE_STRING) {
+			char *valstr;
+			VERIFY(nvpair_value_string(elem, &valstr) == 0);
+			if (strlen(valstr) >= (version <
+			    SPA_VERSION_STMF_PROP ?
+			    ZAP_OLDMAXVALUELEN : ZAP_MAXVALUELEN)) {
+				dsl_dataset_rele(ds, FTAG);
+				return (E2BIG);
+			}
+		}
+	}
+
+	if (dsl_dataset_is_snapshot(ds) &&
+	    version < SPA_VERSION_SNAP_PROPS) {
+		dsl_dataset_rele(ds, FTAG);
+		return (ENOTSUP);
+	}
+
+	err = dsl_sync_task_do(ds->ds_dir->dd_pool,
+	    NULL, dsl_props_set_sync, ds, nvl, 2);
+
+	dsl_dataset_rele(ds, FTAG);
+	return (err);
+}
+
 /*
  * Iterate over all properties for this dataset and return them in an nvlist.
  */
diff --git a/module/zfs/dsl_scrub.c b/module/zfs/dsl_scrub.c
index 783604101..8a802b53a 100644
--- a/module/zfs/dsl_scrub.c
+++ b/module/zfs/dsl_scrub.c
@@ -45,6 +45,8 @@ typedef int (scrub_cb_t)(dsl_pool_t *, const blkptr_t *, const zbookmark_t *);
 
 static scrub_cb_t dsl_pool_scrub_clean_cb;
 static dsl_syncfunc_t dsl_pool_scrub_cancel_sync;
+static void scrub_visitdnode(dsl_pool_t *dp, dnode_phys_t *dnp, arc_buf_t *buf,
+    uint64_t objset, uint64_t object);
 
 int zfs_scrub_min_time = 1; /* scrub for at least 1 sec each txg */
 int zfs_resilver_min_time = 3; /* resilver for at least 3 sec each txg */
@@ -348,6 +350,12 @@ traverse_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
 	if (bp->blk_birth <= dp->dp_scrub_min_txg)
 		return;
 
+	/*
+	 * One block ("stubby") can be allocated a long time ago; we
+	 * want to visit that one because it has been allocated
+	 * (on-disk) even if it hasn't been claimed (even though for
+	 * plain scrub there's nothing to do to it).
+	 */
 	if (claim_txg == 0 && bp->blk_birth >= spa_first_txg(dp->dp_spa))
 		return;
 
@@ -373,6 +381,11 @@ traverse_zil_record(zilog_t *zilog, lr_t *lrc, void *arg, uint64_t claim_txg)
 		if (bp->blk_birth <= dp->dp_scrub_min_txg)
 			return;
 
+		/*
+		 * birth can be < claim_txg if this record's txg is
+		 * already txg sync'ed (but this log block contains
+		 * other records that are not synced)
+		 */
 		if (claim_txg == 0 || bp->blk_birth < claim_txg)
 			return;
 
@@ -472,7 +485,7 @@ scrub_visitbp(dsl_pool_t *dp, dnode_phys_t *dnp,
 	} else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
 		uint32_t flags = ARC_WAIT;
 		dnode_phys_t *child_dnp;
-		int i, j;
+		int i;
 		int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
 
 		err = arc_read(NULL, dp->dp_spa, bp, pbuf,
@@ -487,20 +500,12 @@ scrub_visitbp(dsl_pool_t *dp, dnode_phys_t *dnp,
 		child_dnp = buf->b_data;
 
 		for (i = 0; i < epb; i++, child_dnp++) {
-			for (j = 0; j < child_dnp->dn_nblkptr; j++) {
-				zbookmark_t czb;
-
-				SET_BOOKMARK(&czb, zb->zb_objset,
-				    zb->zb_blkid * epb + i,
-				    child_dnp->dn_nlevels - 1, j);
-				scrub_visitbp(dp, child_dnp, buf,
-				    &child_dnp->dn_blkptr[j], &czb);
-			}
+			scrub_visitdnode(dp, child_dnp, buf, zb->zb_objset,
+			    zb->zb_blkid * epb + i);
 		}
 	} else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
 		uint32_t flags = ARC_WAIT;
 		objset_phys_t *osp;
-		int j;
 
 		err = arc_read_nolock(NULL, dp->dp_spa, bp,
 		    arc_getbuf_func, &buf,
@@ -516,13 +521,13 @@ scrub_visitbp(dsl_pool_t *dp, dnode_phys_t *dnp,
 
 		traverse_zil(dp, &osp->os_zil_header);
 
-		for (j = 0; j < osp->os_meta_dnode.dn_nblkptr; j++) {
-			zbookmark_t czb;
-
-			SET_BOOKMARK(&czb, zb->zb_objset, 0,
-			    osp->os_meta_dnode.dn_nlevels - 1, j);
-			scrub_visitbp(dp, &osp->os_meta_dnode, buf,
-			    &osp->os_meta_dnode.dn_blkptr[j], &czb);
+		scrub_visitdnode(dp, &osp->os_meta_dnode,
+		    buf, zb->zb_objset, 0);
+		if (arc_buf_size(buf) >= sizeof (objset_phys_t)) {
+			scrub_visitdnode(dp, &osp->os_userused_dnode,
+			    buf, zb->zb_objset, 0);
+			scrub_visitdnode(dp, &osp->os_groupused_dnode,
+			    buf, zb->zb_objset, 0);
 		}
 	}
 
@@ -532,6 +537,21 @@ scrub_visitbp(dsl_pool_t *dp, dnode_phys_t *dnp,
 }
 
 static void
+scrub_visitdnode(dsl_pool_t *dp, dnode_phys_t *dnp, arc_buf_t *buf,
+    uint64_t objset, uint64_t object)
+{
+	int j;
+
+	for (j = 0; j < dnp->dn_nblkptr; j++) {
+		zbookmark_t czb;
+
+		SET_BOOKMARK(&czb, objset, object, dnp->dn_nlevels - 1, j);
+		scrub_visitbp(dp, dnp, buf, &dnp->dn_blkptr[j], &czb);
+	}
+
+}
+
+static void
 scrub_visit_rootbp(dsl_pool_t *dp, dsl_dataset_t *ds, blkptr_t *bp)
 {
 	zbookmark_t zb;
diff --git a/module/zfs/fletcher.c b/module/zfs/fletcher.c
index edda3c9a9..54247d724 100644
--- a/module/zfs/fletcher.c
+++ b/module/zfs/fletcher.c
@@ -19,11 +19,111 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
+/*
+ * Fletcher Checksums
+ * ------------------
+ *
+ * ZFS's 2nd and 4th order Fletcher checksums are defined by the following
+ * recurrence relations:
+ *
+ *	a  = a    + f
+ *	 i    i-1    i-1
+ *
+ *	b  = b    + a
+ *	 i    i-1    i
+ *
+ *	c  = c    + b		(fletcher-4 only)
+ *	 i    i-1    i
+ *
+ *	d  = d    + c		(fletcher-4 only)
+ *	 i    i-1    i
+ *
+ * Where
+ *	a_0 = b_0 = c_0 = d_0 = 0
+ * and
+ *	f_0 .. f_(n-1) are the input data.
+ *
+ * Using standard techniques, these translate into the following series:
+ *
+ *	     __n_			     __n_
+ *	     \   |			     \   |
+ *	a  =  >     f			b  =  >     i * f
+ *	 n   /___|   n - i		 n   /___|	 n - i
+ *	     i = 1			     i = 1
+ *
+ *
+ *	     __n_			     __n_
+ *	     \   |  i*(i+1)		     \   |  i*(i+1)*(i+2)
+ *	c  =  >     ------- f		d  =  >     ------------- f
+ *	 n   /___|     2     n - i	 n   /___|	  6	   n - i
+ *	     i = 1			     i = 1
+ *
+ * For fletcher-2, the f_is are 64-bit, and [ab]_i are 64-bit accumulators.
+ * Since the additions are done mod (2^64), errors in the high bits may not
+ * be noticed.  For this reason, fletcher-2 is deprecated.
+ *
+ * For fletcher-4, the f_is are 32-bit, and [abcd]_i are 64-bit accumulators.
+ * A conservative estimate of how big the buffer can get before we overflow
+ * can be estimated using f_i = 0xffffffff for all i:
+ *
+ * % bc
+ *  f=2^32-1;d=0; for (i = 1; d<2^64; i++) { d += f*i*(i+1)*(i+2)/6 }; (i-1)*4
+ * 2264
+ *  quit
+ * %
+ *
+ * So blocks of up to 2k will not overflow.  Our largest block size is
+ * 128k, which has 32k 4-byte words, so we can compute the largest possible
+ * accumulators, then divide by 2^64 to figure the max amount of overflow:
+ *
+ * % bc
+ *  a=b=c=d=0; f=2^32-1; for (i=1; i<=32*1024; i++) { a+=f; b+=a; c+=b; d+=c }
+ *  a/2^64;b/2^64;c/2^64;d/2^64
+ * 0
+ * 0
+ * 1365
+ * 11186858
+ *  quit
+ * %
+ *
+ * So a and b cannot overflow.  To make sure each bit of input has some
+ * effect on the contents of c and d, we can look at what the factors of
+ * the coefficients in the equations for c_n and d_n are.  The number of 2s
+ * in the factors determines the lowest set bit in the multiplier.  Running
+ * through the cases for n*(n+1)/2 reveals that the highest power of 2 is
+ * 2^14, and for n*(n+1)*(n+2)/6 it is 2^15.  So while some data may overflow
+ * the 64-bit accumulators, every bit of every f_i effects every accumulator,
+ * even for 128k blocks.
+ *
+ * If we wanted to make a stronger version of fletcher4 (fletcher4c?),
+ * we could do our calculations mod (2^32 - 1) by adding in the carries
+ * periodically, and store the number of carries in the top 32-bits.
+ *
+ * --------------------
+ * Checksum Performance
+ * --------------------
+ *
+ * There are two interesting components to checksum performance: cached and
+ * uncached performance.  With cached data, fletcher-2 is about four times
+ * faster than fletcher-4.  With uncached data, the performance difference is
+ * negligible, since the cost of a cache fill dominates the processing time.
+ * Even though fletcher-4 is slower than fletcher-2, it is still a pretty
+ * efficient pass over the data.
+ *
+ * In normal operation, the data which is being checksummed is in a buffer
+ * which has been filled either by:
+ *
+ *	1. a compression step, which will be mostly cached, or
+ *	2. a bcopy() or copyin(), which will be uncached (because the
+ *	   copy is cache-bypassing).
+ *
+ * For both cached and uncached data, both fletcher checksums are much faster
+ * than sha-256, and slower than 'off', which doesn't touch the data at all.
+ */
 
 #include <sys/types.h>
 #include <sys/sysmacros.h>
diff --git a/module/zfs/include/sys/arc.h b/module/zfs/include/sys/arc.h
index c402d3d58..6e5955b7c 100644
--- a/module/zfs/include/sys/arc.h
+++ b/module/zfs/include/sys/arc.h
@@ -85,6 +85,8 @@ void *arc_data_buf_alloc(uint64_t space);
 void arc_data_buf_free(void *buf, uint64_t space);
 arc_buf_t *arc_buf_alloc(spa_t *spa, int size, void *tag,
     arc_buf_contents_t type);
+arc_buf_t *arc_loan_buf(spa_t *spa, int size);
+void arc_return_buf(arc_buf_t *buf, void *tag);
 void arc_buf_add_ref(arc_buf_t *buf, void *tag);
 int arc_buf_remove_ref(arc_buf_t *buf, void *tag);
 int arc_buf_size(arc_buf_t *buf);
@@ -134,7 +136,7 @@ void arc_fini(void);
  * Level 2 ARC
  */
 
-void l2arc_add_vdev(spa_t *spa, vdev_t *vd, uint64_t start, uint64_t end);
+void l2arc_add_vdev(spa_t *spa, vdev_t *vd);
 void l2arc_remove_vdev(vdev_t *vd);
 boolean_t l2arc_vdev_present(vdev_t *vd);
 void l2arc_init(void);
diff --git a/module/zfs/include/sys/dbuf.h b/module/zfs/include/sys/dbuf.h
index 75ce27264..267852519 100644
--- a/module/zfs/include/sys/dbuf.h
+++ b/module/zfs/include/sys/dbuf.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -264,6 +264,7 @@ void dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx);
 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx);
 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx);
 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx);
+void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx);
 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
 
 void dbuf_clear(dmu_buf_impl_t *db);
diff --git a/module/zfs/include/sys/dmu.h b/module/zfs/include/sys/dmu.h
index 3b1e5c8fb..a363d7032 100644
--- a/module/zfs/include/sys/dmu.h
+++ b/module/zfs/include/sys/dmu.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -60,6 +60,7 @@ struct zbookmark;
 struct spa;
 struct nvlist;
 struct objset_impl;
+struct arc_buf;
 
 typedef struct objset objset_t;
 typedef struct dmu_tx dmu_tx_t;
@@ -114,6 +115,8 @@ typedef enum dmu_object_type {
 	DMU_OT_FUID_SIZE,		/* FUID table size UINT64 */
 	DMU_OT_NEXT_CLONES,		/* ZAP */
 	DMU_OT_SCRUB_QUEUE,		/* ZAP */
+	DMU_OT_USERGROUP_USED,		/* ZAP */
+	DMU_OT_USERGROUP_QUOTA,		/* ZAP */
 	DMU_OT_NUMTYPES
 } dmu_object_type_t;
 
@@ -156,6 +159,9 @@ void zfs_znode_byteswap(void *buf, size_t size);
 #define	DMU_MAX_ACCESS (10<<20) /* 10MB */
 #define	DMU_MAX_DELETEBLKCNT (20480) /* ~5MB of indirect blocks */
 
+#define	DMU_USERUSED_OBJECT	(-1ULL)
+#define	DMU_GROUPUSED_OBJECT	(-2ULL)
+
 /*
  * Public routines to create, destroy, open, and close objsets.
  */
@@ -171,7 +177,8 @@ int dmu_objset_create(const char *name, dmu_objset_type_t type,
 int dmu_objset_destroy(const char *name);
 int dmu_snapshots_destroy(char *fsname, char *snapname);
 int dmu_objset_rollback(objset_t *os);
-int dmu_objset_snapshot(char *fsname, char *snapname, boolean_t recursive);
+int dmu_objset_snapshot(char *fsname, char *snapname, struct nvlist *props,
+    boolean_t recursive);
 int dmu_objset_rename(const char *name, const char *newname,
     boolean_t recursive);
 int dmu_objset_find(char *name, int func(char *, void *), void *arg,
@@ -235,7 +242,7 @@ uint64_t dmu_object_alloc(objset_t *os, dmu_object_type_t ot,
 int dmu_object_claim(objset_t *os, uint64_t object, dmu_object_type_t ot,
     int blocksize, dmu_object_type_t bonus_type, int bonus_len, dmu_tx_t *tx);
 int dmu_object_reclaim(objset_t *os, uint64_t object, dmu_object_type_t ot,
-    int blocksize, dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
+    int blocksize, dmu_object_type_t bonustype, int bonuslen);
 
 /*
  * Free an object from this objset.
@@ -398,6 +405,11 @@ void *dmu_buf_get_user(dmu_buf_t *db);
 void dmu_buf_will_dirty(dmu_buf_t *db, dmu_tx_t *tx);
 
 /*
+ * Tells if the given dbuf is freeable.
+ */
+boolean_t dmu_buf_freeable(dmu_buf_t *);
+
+/*
  * You must create a transaction, then hold the objects which you will
  * (or might) modify as part of this transaction.  Then you must assign
  * the transaction to a transaction group.  Once the transaction has
@@ -422,7 +434,7 @@ dmu_tx_t *dmu_tx_create(objset_t *os);
 void dmu_tx_hold_write(dmu_tx_t *tx, uint64_t object, uint64_t off, int len);
 void dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off,
     uint64_t len);
-void dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, char *name);
+void dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, const char *name);
 void dmu_tx_hold_bonus(dmu_tx_t *tx, uint64_t object);
 void dmu_tx_abort(dmu_tx_t *tx);
 int dmu_tx_assign(dmu_tx_t *tx, uint64_t txg_how);
@@ -445,8 +457,10 @@ int dmu_free_object(objset_t *os, uint64_t object);
  * Canfail routines will return 0 on success, or an errno if there is a
  * nonrecoverable I/O error.
  */
+#define	DMU_READ_PREFETCH	0 /* prefetch */
+#define	DMU_READ_NO_PREFETCH	1 /* don't prefetch */
 int dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
-	void *buf);
+	void *buf, uint32_t flags);
 void dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 	const void *buf, dmu_tx_t *tx);
 void dmu_prealloc(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
@@ -456,6 +470,10 @@ int dmu_write_uio(objset_t *os, uint64_t object, struct uio *uio, uint64_t size,
     dmu_tx_t *tx);
 int dmu_write_pages(objset_t *os, uint64_t object, uint64_t offset,
     uint64_t size, struct page *pp, dmu_tx_t *tx);
+struct arc_buf *dmu_request_arcbuf(dmu_buf_t *handle, int size);
+void dmu_return_arcbuf(struct arc_buf *buf);
+void dmu_assign_arcbuf(dmu_buf_t *handle, uint64_t offset, struct arc_buf *buf,
+    dmu_tx_t *tx);
 
 extern int zfs_prefetch_disable;
 
@@ -562,6 +580,12 @@ extern int dmu_snapshot_realname(objset_t *os, char *name, char *real,
     int maxlen, boolean_t *conflict);
 extern int dmu_dir_list_next(objset_t *os, int namelen, char *name,
     uint64_t *idp, uint64_t *offp);
+
+typedef void objset_used_cb_t(objset_t *os, dmu_object_type_t bonustype,
+    void *oldbonus, void *newbonus, uint64_t oldused, uint64_t newused,
+    dmu_tx_t *tx);
+extern void dmu_objset_register_type(dmu_objset_type_t ost,
+    objset_used_cb_t *cb);
 extern void dmu_objset_set_user(objset_t *os, void *user_ptr);
 extern void *dmu_objset_get_user(objset_t *os);
 
diff --git a/module/zfs/include/sys/dmu_objset.h b/module/zfs/include/sys/dmu_objset.h
index 1d6572780..82cb6ad7d 100644
--- a/module/zfs/include/sys/dmu_objset.h
+++ b/module/zfs/include/sys/dmu_objset.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -42,12 +42,20 @@ struct dsl_dataset;
 struct dmu_tx;
 struct objset_impl;
 
+#define	OBJSET_PHYS_SIZE 2048
+#define	OBJSET_OLD_PHYS_SIZE 1024
+
+#define	OBJSET_FLAG_USERACCOUNTING_COMPLETE	(1ULL<<0)
+
 typedef struct objset_phys {
 	dnode_phys_t os_meta_dnode;
 	zil_header_t os_zil_header;
 	uint64_t os_type;
-	char os_pad[1024 - sizeof (dnode_phys_t) - sizeof (zil_header_t) -
-	    sizeof (uint64_t)];
+	uint64_t os_flags;
+	char os_pad[OBJSET_PHYS_SIZE - sizeof (dnode_phys_t)*3 -
+	    sizeof (zil_header_t) - sizeof (uint64_t)*2];
+	dnode_phys_t os_userused_dnode;
+	dnode_phys_t os_groupused_dnode;
 } objset_phys_t;
 
 struct objset {
@@ -62,6 +70,8 @@ typedef struct objset_impl {
 	arc_buf_t *os_phys_buf;
 	objset_phys_t *os_phys;
 	dnode_t *os_meta_dnode;
+	dnode_t *os_userused_dnode;
+	dnode_t *os_groupused_dnode;
 	zilog_t *os_zil;
 	objset_t os;
 	uint8_t os_checksum;	/* can change, under dsl_dir's locks */
@@ -74,6 +84,8 @@ typedef struct objset_impl {
 	struct dmu_tx *os_synctx; /* XXX sketchy */
 	blkptr_t *os_rootbp;
 	zil_header_t os_zil_header;
+	list_t os_synced_dnodes;
+	uint64_t os_flags;
 
 	/* Protected by os_obj_lock */
 	kmutex_t os_obj_lock;
@@ -92,6 +104,7 @@ typedef struct objset_impl {
 } objset_impl_t;
 
 #define	DMU_META_DNODE_OBJECT	0
+#define	DMU_OBJECT_IS_SPECIAL(obj) ((int64_t)(obj) <= 0)
 
 #define	DMU_OS_IS_L2CACHEABLE(os)				\
 	((os)->os_secondary_cache == ZFS_CACHE_ALL ||		\
@@ -106,7 +119,8 @@ int dmu_objset_create(const char *name, dmu_objset_type_t type,
     void (*func)(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx), void *arg);
 int dmu_objset_destroy(const char *name);
 int dmu_objset_rollback(objset_t *os);
-int dmu_objset_snapshot(char *fsname, char *snapname, boolean_t recursive);
+int dmu_objset_snapshot(char *fsname, char *snapname, nvlist_t *props,
+    boolean_t recursive);
 void dmu_objset_stats(objset_t *os, nvlist_t *nv);
 void dmu_objset_fast_stat(objset_t *os, dmu_objset_stats_t *stat);
 void dmu_objset_space(objset_t *os, uint64_t *refdbytesp, uint64_t *availbytesp,
@@ -127,6 +141,10 @@ objset_impl_t *dmu_objset_create_impl(spa_t *spa, struct dsl_dataset *ds,
 int dmu_objset_open_impl(spa_t *spa, struct dsl_dataset *ds, blkptr_t *bp,
     objset_impl_t **osip);
 void dmu_objset_evict(struct dsl_dataset *ds, void *arg);
+void dmu_objset_do_userquota_callbacks(objset_impl_t *os, dmu_tx_t *tx);
+boolean_t dmu_objset_userused_enabled(objset_impl_t *os);
+int dmu_objset_userspace_upgrade(objset_t *os);
+boolean_t dmu_objset_userspace_present(objset_t *os);
 
 #ifdef	__cplusplus
 }
diff --git a/module/zfs/include/sys/dnode.h b/module/zfs/include/sys/dnode.h
index be9e56908..48e4da8cd 100644
--- a/module/zfs/include/sys/dnode.h
+++ b/module/zfs/include/sys/dnode.h
@@ -98,7 +98,8 @@ enum dnode_dirtycontext {
 };
 
 /* Is dn_used in bytes?  if not, it's in multiples of SPA_MINBLOCKSIZE */
-#define	DNODE_FLAG_USED_BYTES	(1<<0)
+#define	DNODE_FLAG_USED_BYTES		(1<<0)
+#define	DNODE_FLAG_USERUSED_ACCOUNTED	(1<<1)
 
 typedef struct dnode_phys {
 	uint8_t dn_type;		/* dmu_object_type_t */
@@ -131,10 +132,7 @@ typedef struct dnode {
 	 */
 	krwlock_t dn_struct_rwlock;
 
-	/*
-	 * Our link on dataset's dd_dnodes list.
-	 * Protected by dd_accounting_mtx.
-	 */
+	/* Our link on dn_objset->os_dnodes list; protected by os_lock.  */
 	list_node_t dn_link;
 
 	/* immutable: */
@@ -191,6 +189,9 @@ typedef struct dnode {
 	/* parent IO for current sync write */
 	zio_t *dn_zio;
 
+	/* used in syncing context */
+	dnode_phys_t *dn_oldphys;
+
 	/* holds prefetch structure */
 	struct zfetch	dn_zfetch;
 } dnode_t;
diff --git a/module/zfs/include/sys/dsl_dataset.h b/module/zfs/include/sys/dsl_dataset.h
index 8665aec2d..a1c2896e3 100644
--- a/module/zfs/include/sys/dsl_dataset.h
+++ b/module/zfs/include/sys/dsl_dataset.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -195,7 +195,7 @@ void dsl_dataset_sync(dsl_dataset_t *os, zio_t *zio, dmu_tx_t *tx);
 void dsl_dataset_block_born(dsl_dataset_t *ds, blkptr_t *bp, dmu_tx_t *tx);
 int dsl_dataset_block_kill(dsl_dataset_t *ds, blkptr_t *bp, zio_t *pio,
     dmu_tx_t *tx);
-int dsl_dataset_block_freeable(dsl_dataset_t *ds, uint64_t blk_birth);
+boolean_t dsl_dataset_block_freeable(dsl_dataset_t *ds, uint64_t blk_birth);
 uint64_t dsl_dataset_prev_snap_txg(dsl_dataset_t *ds);
 
 void dsl_dataset_dirty(dsl_dataset_t *ds, dmu_tx_t *tx);
diff --git a/module/zfs/include/sys/dsl_deleg.h b/module/zfs/include/sys/dsl_deleg.h
index a29e44e67..b064c9228 100644
--- a/module/zfs/include/sys/dsl_deleg.h
+++ b/module/zfs/include/sys/dsl_deleg.h
@@ -19,15 +19,13 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
 #ifndef	_SYS_DSL_DELEG_H
 #define	_SYS_DSL_DELEG_H
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/dmu.h>
 #include <sys/dsl_pool.h>
 #include <sys/zfs_context.h>
@@ -51,6 +49,10 @@ extern "C" {
 #define	ZFS_DELEG_PERM_ALLOW		"allow"
 #define	ZFS_DELEG_PERM_USERPROP		"userprop"
 #define	ZFS_DELEG_PERM_VSCAN		"vscan"
+#define	ZFS_DELEG_PERM_USERQUOTA	"userquota"
+#define	ZFS_DELEG_PERM_GROUPQUOTA	"groupquota"
+#define	ZFS_DELEG_PERM_USERUSED		"userused"
+#define	ZFS_DELEG_PERM_GROUPUSED	"groupused"
 
 /*
  * Note: the names of properties that are marked delegatable are also
diff --git a/module/zfs/include/sys/dsl_dir.h b/module/zfs/include/sys/dsl_dir.h
index 86b9636ce..56d06388c 100644
--- a/module/zfs/include/sys/dsl_dir.h
+++ b/module/zfs/include/sys/dsl_dir.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -107,7 +107,6 @@ int dsl_dir_open_obj(dsl_pool_t *dp, uint64_t ddobj,
     const char *tail, void *tag, dsl_dir_t **);
 void dsl_dir_name(dsl_dir_t *dd, char *buf);
 int dsl_dir_namelen(dsl_dir_t *dd);
-int dsl_dir_is_private(dsl_dir_t *dd);
 uint64_t dsl_dir_create_sync(dsl_pool_t *dp, dsl_dir_t *pds,
     const char *name, dmu_tx_t *tx);
 dsl_checkfunc_t dsl_dir_destroy_check;
diff --git a/module/zfs/include/sys/dsl_pool.h b/module/zfs/include/sys/dsl_pool.h
index 3bb4ad4ef..d8da295f3 100644
--- a/module/zfs/include/sys/dsl_pool.h
+++ b/module/zfs/include/sys/dsl_pool.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -77,6 +77,7 @@ typedef struct dsl_pool {
 	struct dsl_dir *dp_mos_dir;
 	struct dsl_dataset *dp_origin_snap;
 	uint64_t dp_root_dir_obj;
+	struct taskq *dp_vnrele_taskq;
 
 	/* No lock needed - sync context only */
 	blkptr_t dp_meta_rootbp;
@@ -143,6 +144,8 @@ int dsl_pool_scrub_clean(dsl_pool_t *dp);
 void dsl_pool_scrub_sync(dsl_pool_t *dp, dmu_tx_t *tx);
 void dsl_pool_scrub_restart(dsl_pool_t *dp);
 
+taskq_t *dsl_pool_vnrele_taskq(dsl_pool_t *dp);
+
 #ifdef	__cplusplus
 }
 #endif
diff --git a/module/zfs/include/sys/dsl_prop.h b/module/zfs/include/sys/dsl_prop.h
index d66caa86c..26018a46d 100644
--- a/module/zfs/include/sys/dsl_prop.h
+++ b/module/zfs/include/sys/dsl_prop.h
@@ -19,18 +19,17 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
 #ifndef	_SYS_DSL_PROP_H
 #define	_SYS_DSL_PROP_H
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/dmu.h>
 #include <sys/dsl_pool.h>
 #include <sys/zfs_context.h>
+#include <sys/dsl_synctask.h>
 
 #ifdef	__cplusplus
 extern "C" {
@@ -66,8 +65,10 @@ int dsl_prop_get_ds(struct dsl_dataset *ds, const char *propname,
 int dsl_prop_get_dd(struct dsl_dir *dd, const char *propname,
     int intsz, int numints, void *buf, char *setpoint);
 
+dsl_syncfunc_t dsl_props_set_sync;
 int dsl_prop_set(const char *ddname, const char *propname,
     int intsz, int numints, const void *buf);
+int dsl_props_set(const char *dsname, nvlist_t *nvl);
 void dsl_prop_set_uint64_sync(dsl_dir_t *dd, const char *name, uint64_t val,
     cred_t *cr, dmu_tx_t *tx);
 
diff --git a/module/zfs/include/sys/metaslab.h b/module/zfs/include/sys/metaslab.h
index 1c9d89e8f..5d3e11c97 100644
--- a/module/zfs/include/sys/metaslab.h
+++ b/module/zfs/include/sys/metaslab.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -39,6 +39,8 @@ extern "C" {
 typedef struct metaslab_class metaslab_class_t;
 typedef struct metaslab_group metaslab_group_t;
 
+extern space_map_ops_t *zfs_metaslab_ops;
+
 extern metaslab_t *metaslab_init(metaslab_group_t *mg, space_map_obj_t *smo,
     uint64_t start, uint64_t size, uint64_t txg);
 extern void metaslab_fini(metaslab_t *msp);
@@ -55,7 +57,7 @@ extern void metaslab_free(spa_t *spa, const blkptr_t *bp, uint64_t txg,
     boolean_t now);
 extern int metaslab_claim(spa_t *spa, const blkptr_t *bp, uint64_t txg);
 
-extern metaslab_class_t *metaslab_class_create(void);
+extern metaslab_class_t *metaslab_class_create(space_map_ops_t *ops);
 extern void metaslab_class_destroy(metaslab_class_t *mc);
 extern void metaslab_class_add(metaslab_class_t *mc, metaslab_group_t *mg);
 extern void metaslab_class_remove(metaslab_class_t *mc, metaslab_group_t *mg);
diff --git a/module/zfs/include/sys/metaslab_impl.h b/module/zfs/include/sys/metaslab_impl.h
index 5980cbc84..d67dea7e9 100644
--- a/module/zfs/include/sys/metaslab_impl.h
+++ b/module/zfs/include/sys/metaslab_impl.h
@@ -19,15 +19,13 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
 #ifndef _SYS_METASLAB_IMPL_H
 #define	_SYS_METASLAB_IMPL_H
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/metaslab.h>
 #include <sys/space_map.h>
 #include <sys/vdev.h>
@@ -41,6 +39,7 @@ extern "C" {
 struct metaslab_class {
 	metaslab_group_t	*mc_rotor;
 	uint64_t		mc_allocated;
+	space_map_ops_t		*mc_ops;
 };
 
 struct metaslab_group {
diff --git a/module/zfs/include/sys/spa.h b/module/zfs/include/sys/spa.h
index 029123dfe..c7ae4022e 100644
--- a/module/zfs/include/sys/spa.h
+++ b/module/zfs/include/sys/spa.h
@@ -324,12 +324,9 @@ extern int spa_get_stats(const char *pool, nvlist_t **config,
     char *altroot, size_t buflen);
 extern int spa_create(const char *pool, nvlist_t *config, nvlist_t *props,
     const char *history_str, nvlist_t *zplprops);
-extern int spa_check_rootconf(char *devpath, char *devid,
-    nvlist_t **bestconf, uint64_t *besttxg);
-extern boolean_t spa_rootdev_validate(nvlist_t *nv);
 extern int spa_import_rootpool(char *devpath, char *devid);
 extern int spa_import(const char *pool, nvlist_t *config, nvlist_t *props);
-extern int spa_import_faulted(const char *, nvlist_t *, nvlist_t *);
+extern int spa_import_verbatim(const char *, nvlist_t *, nvlist_t *);
 extern nvlist_t *spa_tryimport(nvlist_t *tryconfig);
 extern int spa_destroy(char *pool);
 extern int spa_export(char *pool, nvlist_t **oldconfig, boolean_t force,
@@ -347,6 +344,7 @@ extern void spa_inject_delref(spa_t *spa);
 #define	SPA_ASYNC_PROBE		0x04
 #define	SPA_ASYNC_RESILVER_DONE	0x08
 #define	SPA_ASYNC_RESILVER	0x10
+#define	SPA_ASYNC_AUTOEXPAND	0x20
 
 /* device manipulation */
 extern int spa_vdev_add(spa_t *spa, nvlist_t *nvroot);
@@ -356,6 +354,7 @@ extern int spa_vdev_detach(spa_t *spa, uint64_t guid, uint64_t pguid,
     int replace_done);
 extern int spa_vdev_remove(spa_t *spa, uint64_t guid, boolean_t unspare);
 extern int spa_vdev_setpath(spa_t *spa, uint64_t guid, const char *newpath);
+extern int spa_vdev_setfru(spa_t *spa, uint64_t guid, const char *newfru);
 
 /* spare state (which is global across all pools) */
 extern void spa_spare_add(vdev_t *vd);
diff --git a/module/zfs/include/sys/spa_boot.h b/module/zfs/include/sys/spa_boot.h
index b56073b97..1d3622f5a 100644
--- a/module/zfs/include/sys/spa_boot.h
+++ b/module/zfs/include/sys/spa_boot.h
@@ -19,15 +19,13 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
 #ifndef _SYS_SPA_BOOT_H
 #define	_SYS_SPA_BOOT_H
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/nvpair.h>
 
 #ifdef	__cplusplus
@@ -36,7 +34,6 @@ extern "C" {
 
 extern char *spa_get_bootprop(char *prop);
 extern void spa_free_bootprop(char *prop);
-extern int spa_get_rootconf(char *devpath, char *devid, nvlist_t **bestconf_p);
 
 #ifdef	__cplusplus
 }
diff --git a/module/zfs/include/sys/spa_impl.h b/module/zfs/include/sys/spa_impl.h
index 588b4f5a9..12999ee9e 100644
--- a/module/zfs/include/sys/spa_impl.h
+++ b/module/zfs/include/sys/spa_impl.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -141,9 +141,6 @@ struct spa {
 	int		spa_async_suspended;	/* async tasks suspended */
 	kcondvar_t	spa_async_cv;		/* wait for thread_exit() */
 	uint16_t	spa_async_tasks;	/* async task mask */
-	kmutex_t	spa_async_root_lock;	/* protects async root count */
-	uint64_t	spa_async_root_count;	/* number of async root zios */
-	kcondvar_t	spa_async_root_cv;	/* notify when count == 0 */
 	char		*spa_root;		/* alternate root directory */
 	uint64_t	spa_ena;		/* spa-wide ereport ENA */
 	boolean_t	spa_last_open_failed;	/* true if last open faled */
@@ -163,15 +160,16 @@ struct spa {
 	uint64_t	spa_failmode;		/* failure mode for the pool */
 	uint64_t	spa_delegation;		/* delegation on/off */
 	list_t		spa_config_list;	/* previous cache file(s) */
+	zio_t		*spa_async_zio_root;	/* root of all async I/O */
 	zio_t		*spa_suspend_zio_root;	/* root of all suspended I/O */
 	kmutex_t	spa_suspend_lock;	/* protects suspend_zio_root */
 	kcondvar_t	spa_suspend_cv;		/* notification of resume */
 	uint8_t		spa_suspended;		/* pool is suspended */
-	boolean_t	spa_import_faulted;	/* allow faulted vdevs */
 	boolean_t	spa_is_root;		/* pool is root */
 	int		spa_minref;		/* num refs when first opened */
 	int		spa_mode;		/* FREAD | FWRITE */
 	spa_log_state_t spa_log_state;		/* log state */
+	uint64_t	spa_autoexpand;		/* lun expansion on/off */
 	/*
 	 * spa_refcnt & spa_config_lock must be the last elements
 	 * because refcount_t changes size based on compilation options.
diff --git a/module/zfs/include/sys/space_map.h b/module/zfs/include/sys/space_map.h
index 8d7860660..a682bbd40 100644
--- a/module/zfs/include/sys/space_map.h
+++ b/module/zfs/include/sys/space_map.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -46,12 +46,14 @@ typedef struct space_map {
 	uint8_t		sm_loading;	/* map loading? */
 	kcondvar_t	sm_load_cv;	/* map load completion */
 	space_map_ops_t	*sm_ops;	/* space map block picker ops vector */
+	avl_tree_t	*sm_pp_root;	/* picker-private AVL tree */
 	void		*sm_ppd;	/* picker-private data */
 	kmutex_t	*sm_lock;	/* pointer to lock that protects map */
 } space_map_t;
 
 typedef struct space_seg {
 	avl_node_t	ss_node;	/* AVL node */
+	avl_node_t	ss_pp_node;	/* AVL picker-private node */
 	uint64_t	ss_start;	/* starting offset of this segment */
 	uint64_t	ss_end;		/* ending offset (non-inclusive) */
 } space_seg_t;
@@ -74,6 +76,7 @@ struct space_map_ops {
 	uint64_t (*smop_alloc)(space_map_t *sm, uint64_t size);
 	void	(*smop_claim)(space_map_t *sm, uint64_t start, uint64_t size);
 	void	(*smop_free)(space_map_t *sm, uint64_t start, uint64_t size);
+	uint64_t (*smop_max)(space_map_t *sm);
 };
 
 /*
@@ -152,6 +155,7 @@ extern void space_map_unload(space_map_t *sm);
 extern uint64_t space_map_alloc(space_map_t *sm, uint64_t size);
 extern void space_map_claim(space_map_t *sm, uint64_t start, uint64_t size);
 extern void space_map_free(space_map_t *sm, uint64_t start, uint64_t size);
+extern uint64_t space_map_maxsize(space_map_t *sm);
 
 extern void space_map_sync(space_map_t *sm, uint8_t maptype,
     space_map_obj_t *smo, objset_t *os, dmu_tx_t *tx);
diff --git a/module/zfs/include/sys/vdev.h b/module/zfs/include/sys/vdev.h
index b8313a920..71b9b12d6 100644
--- a/module/zfs/include/sys/vdev.h
+++ b/module/zfs/include/sys/vdev.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -50,7 +50,6 @@ extern int vdev_open(vdev_t *);
 extern int vdev_validate(vdev_t *);
 extern void vdev_close(vdev_t *);
 extern int vdev_create(vdev_t *, uint64_t txg, boolean_t isreplace);
-extern void vdev_init(vdev_t *, uint64_t txg);
 extern void vdev_reopen(vdev_t *);
 extern int vdev_validate_aux(vdev_t *vd);
 extern zio_t *vdev_probe(vdev_t *vd, zio_t *pio);
@@ -71,6 +70,8 @@ extern boolean_t vdev_resilver_needed(vdev_t *vd,
 
 extern int vdev_metaslab_init(vdev_t *vd, uint64_t txg);
 extern void vdev_metaslab_fini(vdev_t *vd);
+extern void vdev_metaslab_set_size(vdev_t *);
+extern void vdev_expand(vdev_t *vd, uint64_t txg);
 
 extern void vdev_get_stats(vdev_t *vd, vdev_stat_t *vs);
 extern void vdev_clear_stats(vdev_t *vd);
@@ -113,7 +114,8 @@ extern void vdev_queue_io_done(zio_t *zio);
 
 extern void vdev_config_dirty(vdev_t *vd);
 extern void vdev_config_clean(vdev_t *vd);
-extern int vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg);
+extern int vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg,
+    boolean_t);
 
 extern void vdev_state_dirty(vdev_t *vd);
 extern void vdev_state_clean(vdev_t *vd);
diff --git a/module/zfs/include/sys/vdev_impl.h b/module/zfs/include/sys/vdev_impl.h
index 652349341..8240b66ac 100644
--- a/module/zfs/include/sys/vdev_impl.h
+++ b/module/zfs/include/sys/vdev_impl.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -113,6 +113,7 @@ struct vdev {
 	uint64_t	vdev_guid;	/* unique ID for this vdev	*/
 	uint64_t	vdev_guid_sum;	/* self guid + all child guids	*/
 	uint64_t	vdev_asize;	/* allocatable device capacity	*/
+	uint64_t	vdev_min_asize;	/* min acceptable asize		*/
 	uint64_t	vdev_ashift;	/* block alignment shift	*/
 	uint64_t	vdev_state;	/* see VDEV_STATE_* #defines	*/
 	uint64_t	vdev_prevstate;	/* used when reopening a vdev	*/
@@ -125,6 +126,7 @@ struct vdev {
 	uint64_t	vdev_children;	/* number of children		*/
 	space_map_t	vdev_dtl[DTL_TYPES]; /* in-core dirty time logs	*/
 	vdev_stat_t	vdev_stat;	/* virtual device statistics	*/
+	boolean_t	vdev_expanding;	/* expand the vdev?		*/
 
 	/*
 	 * Top-level vdev state.
@@ -159,6 +161,7 @@ struct vdev {
 	char		*vdev_path;	/* vdev path (if any)		*/
 	char		*vdev_devid;	/* vdev devid (if any)		*/
 	char		*vdev_physpath;	/* vdev device path (if any)	*/
+	char		*vdev_fru;	/* physical FRU location	*/
 	uint64_t	vdev_not_present; /* not present during import	*/
 	uint64_t	vdev_unspare;	/* unspare when resilvering done */
 	hrtime_t	vdev_last_try;	/* last reopen time		*/
@@ -188,8 +191,9 @@ struct vdev {
 	kmutex_t	vdev_probe_lock; /* protects vdev_probe_zio	*/
 };
 
-#define	VDEV_SKIP_SIZE		(8 << 10)
-#define	VDEV_BOOT_HEADER_SIZE	(8 << 10)
+#define	VDEV_PAD_SIZE		(8 << 10)
+/* 2 padding areas (vl_pad1 and vl_pad2) to skip */
+#define	VDEV_SKIP_SIZE		VDEV_PAD_SIZE * 2
 #define	VDEV_PHYS_SIZE		(112 << 10)
 #define	VDEV_UBERBLOCK_RING	(128 << 10)
 
@@ -201,26 +205,14 @@ struct vdev {
 	offsetof(vdev_label_t, vl_uberblock[(n) << VDEV_UBERBLOCK_SHIFT(vd)])
 #define	VDEV_UBERBLOCK_SIZE(vd)		(1ULL << VDEV_UBERBLOCK_SHIFT(vd))
 
-/* ZFS boot block */
-#define	VDEV_BOOT_MAGIC		0x2f5b007b10cULL
-#define	VDEV_BOOT_VERSION	1		/* version number	*/
-
-typedef struct vdev_boot_header {
-	uint64_t	vb_magic;		/* VDEV_BOOT_MAGIC	*/
-	uint64_t	vb_version;		/* VDEV_BOOT_VERSION	*/
-	uint64_t	vb_offset;		/* start offset	(bytes) */
-	uint64_t	vb_size;		/* size (bytes)		*/
-	char		vb_pad[VDEV_BOOT_HEADER_SIZE - 4 * sizeof (uint64_t)];
-} vdev_boot_header_t;
-
 typedef struct vdev_phys {
 	char		vp_nvlist[VDEV_PHYS_SIZE - sizeof (zio_block_tail_t)];
 	zio_block_tail_t vp_zbt;
 } vdev_phys_t;
 
 typedef struct vdev_label {
-	char		vl_pad[VDEV_SKIP_SIZE];			/*   8K	*/
-	vdev_boot_header_t vl_boot_header;			/*   8K	*/
+	char		vl_pad1[VDEV_PAD_SIZE];			/*  8K */
+	char		vl_pad2[VDEV_PAD_SIZE];			/*  8K */
 	vdev_phys_t	vl_vdev_phys;				/* 112K	*/
 	char		vl_uberblock[VDEV_UBERBLOCK_RING];	/* 128K	*/
 } vdev_label_t;							/* 256K total */
@@ -249,6 +241,7 @@ typedef struct vdev_label {
 #define	VDEV_ALLOC_ADD		1
 #define	VDEV_ALLOC_SPARE	2
 #define	VDEV_ALLOC_L2CACHE	3
+#define	VDEV_ALLOC_ROOTPOOL	4
 
 /*
  * Allocate or free a vdev
@@ -269,6 +262,7 @@ extern void vdev_remove_parent(vdev_t *cvd);
 /*
  * vdev sync load and sync
  */
+extern void vdev_load_log_state(vdev_t *vd, nvlist_t *nv);
 extern void vdev_load(vdev_t *vd);
 extern void vdev_sync(vdev_t *vd, uint64_t txg);
 extern void vdev_sync_done(vdev_t *vd, uint64_t txg);
@@ -290,7 +284,8 @@ extern vdev_ops_t vdev_spare_ops;
  * Common size functions
  */
 extern uint64_t vdev_default_asize(vdev_t *vd, uint64_t psize);
-extern uint64_t vdev_get_rsize(vdev_t *vd);
+extern uint64_t vdev_get_min_asize(vdev_t *vd);
+extern void vdev_set_min_asize(vdev_t *vd);
 
 /*
  * zdb uses this tunable, so it must be declared here to make lint happy.
diff --git a/module/zfs/include/sys/zap.h b/module/zfs/include/sys/zap.h
index f88cc068b..de2053812 100644
--- a/module/zfs/include/sys/zap.h
+++ b/module/zfs/include/sys/zap.h
@@ -19,15 +19,13 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
 #ifndef	_SYS_ZAP_H
 #define	_SYS_ZAP_H
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 /*
  * ZAP - ZFS Attribute Processor
  *
@@ -87,9 +85,6 @@
 extern "C" {
 #endif
 
-#define	ZAP_MAXNAMELEN 256
-#define	ZAP_MAXVALUELEN 1024
-
 /*
  * The matchtype specifies which entry will be accessed.
  * MT_EXACT: only find an exact match (non-normalized)
@@ -186,6 +181,10 @@ int zap_lookup_norm(objset_t *ds, uint64_t zapobj, const char *name,
     matchtype_t mt, char *realname, int rn_len,
     boolean_t *normalization_conflictp);
 
+int zap_count_write(objset_t *os, uint64_t zapobj, const char *name,
+    int add, uint64_t *towrite, uint64_t *tooverwrite,
+    uint64_t dn_datablkshift);
+
 /*
  * Create an attribute with the given name and value.
  *
diff --git a/module/zfs/include/sys/zap_impl.h b/module/zfs/include/sys/zap_impl.h
index 0dc02ab6b..c86bb16de 100644
--- a/module/zfs/include/sys/zap_impl.h
+++ b/module/zfs/include/sys/zap_impl.h
@@ -19,15 +19,13 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
 #ifndef	_SYS_ZAP_IMPL_H
 #define	_SYS_ZAP_IMPL_H
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/zap.h>
 #include <sys/zfs_context.h>
 #include <sys/avl.h>
@@ -195,6 +193,8 @@ int fzap_count(zap_t *zap, uint64_t *count);
 int fzap_lookup(zap_name_t *zn,
     uint64_t integer_size, uint64_t num_integers, void *buf,
     char *realname, int rn_len, boolean_t *normalization_conflictp);
+int fzap_count_write(zap_name_t *zn, int add, uint64_t *towrite,
+    uint64_t *tooverwrite);
 int fzap_add(zap_name_t *zn, uint64_t integer_size, uint64_t num_integers,
     const void *val, dmu_tx_t *tx);
 int fzap_update(zap_name_t *zn,
diff --git a/module/zfs/include/sys/zfs_acl.h b/module/zfs/include/sys/zfs_acl.h
index bd91b33d1..f5e5aa7f4 100644
--- a/module/zfs/include/sys/zfs_acl.h
+++ b/module/zfs/include/sys/zfs_acl.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -114,8 +114,6 @@ typedef struct zfs_acl_phys {
 	uint8_t		z_ace_data[ZFS_ACE_SPACE]; /* space for embedded ACEs */
 } zfs_acl_phys_t;
 
-
-
 typedef struct acl_ops {
 	uint32_t	(*ace_mask_get) (void *acep); /* get  access mask */
 	void 		(*ace_mask_set) (void *acep,
@@ -161,12 +159,21 @@ typedef struct zfs_acl {
 	zfs_acl_node_t	*z_curr_node;	/* current node iterator is handling */
 	list_t		z_acl;		/* chunks of ACE data */
 	acl_ops_t	z_ops;		/* ACL operations */
-	boolean_t	z_has_fuids;	/* FUIDs present in ACL? */
 } zfs_acl_t;
 
 #define	ACL_DATA_ALLOCED	0x1
 #define	ZFS_ACL_SIZE(aclcnt)	(sizeof (ace_t) * (aclcnt))
 
+struct zfs_fuid_info;
+
+typedef struct zfs_acl_ids {
+	uint64_t		z_fuid;		/* file owner fuid */
+	uint64_t		z_fgid;		/* file group owner fuid */
+	uint64_t		z_mode;		/* mode to set on create */
+	zfs_acl_t		*z_aclp;	/* ACL to create with file */
+	struct zfs_fuid_info 	*z_fuidp;	/* for tracking fuids for log */
+} zfs_acl_ids_t;
+
 /*
  * Property values for acl_mode and acl_inherit.
  *
@@ -183,16 +190,18 @@ typedef struct zfs_acl {
 
 struct znode;
 struct zfsvfs;
-struct zfs_fuid_info;
 
 #ifdef _KERNEL
-void zfs_perm_init(struct znode *, struct znode *, int, vattr_t *,
-    dmu_tx_t *, cred_t *, zfs_acl_t *, zfs_fuid_info_t **);
+int zfs_acl_ids_create(struct znode *, int, vattr_t *,
+    cred_t *, vsecattr_t *, zfs_acl_ids_t *);
+void zfs_acl_ids_free(zfs_acl_ids_t *);
+boolean_t zfs_acl_ids_overquota(struct zfsvfs *, zfs_acl_ids_t *);
 int zfs_getacl(struct znode *, vsecattr_t *, boolean_t, cred_t *);
 int zfs_setacl(struct znode *, vsecattr_t *, boolean_t, cred_t *);
 void zfs_acl_rele(void *);
 void zfs_oldace_byteswap(ace_t *, int);
 void zfs_ace_byteswap(void *, size_t, boolean_t);
+extern boolean_t zfs_has_access(struct znode *zp, cred_t *cr);
 extern int zfs_zaccess(struct znode *, int, int, boolean_t, cred_t *);
 extern int zfs_zaccess_rwx(struct znode *, mode_t, int, cred_t *);
 extern int zfs_zaccess_unix(struct znode *, mode_t, cred_t *);
@@ -202,9 +211,9 @@ int zfs_zaccess_delete(struct znode *, struct znode *, cred_t *);
 int zfs_zaccess_rename(struct znode *, struct znode *,
     struct znode *, struct znode *, cred_t *cr);
 void zfs_acl_free(zfs_acl_t *);
-int zfs_vsec_2_aclp(struct zfsvfs *, vtype_t, vsecattr_t *, zfs_acl_t **);
-int zfs_aclset_common(struct znode *, zfs_acl_t *, cred_t *,
-    struct zfs_fuid_info **, dmu_tx_t *);
+int zfs_vsec_2_aclp(struct zfsvfs *, vtype_t, vsecattr_t *, cred_t *,
+    struct zfs_fuid_info **, zfs_acl_t **);
+int zfs_aclset_common(struct znode *, zfs_acl_t *, cred_t *, dmu_tx_t *);
 
 #endif
 
diff --git a/module/zfs/include/sys/zfs_context.h b/module/zfs/include/sys/zfs_context.h
index a5be3e130..40de32084 100644
--- a/module/zfs/include/sys/zfs_context.h
+++ b/module/zfs/include/sys/zfs_context.h
@@ -19,15 +19,13 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
 #ifndef _SYS_ZFS_CONTEXT_H
 #define	_SYS_ZFS_CONTEXT_H
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #ifdef	__cplusplus
 extern "C" {
 #endif
@@ -62,6 +60,7 @@ extern "C" {
 #include <sys/zfs_debug.h>
 #include <sys/sysevent.h>
 #include <sys/sysevent/eventdefs.h>
+#include <sys/sysevent/dev.h>
 #include <sys/fm/util.h>
 
 #define	CPU_SEQID	(CPU->cpu_seqid)
diff --git a/module/zfs/include/sys/zfs_ctldir.h b/module/zfs/include/sys/zfs_ctldir.h
index ce29625d1..c15c946d5 100644
--- a/module/zfs/include/sys/zfs_ctldir.h
+++ b/module/zfs/include/sys/zfs_ctldir.h
@@ -19,15 +19,13 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
 #ifndef	_ZFS_CTLDIR_H
 #define	_ZFS_CTLDIR_H
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/pathname.h>
 #include <sys/vnode.h>
 #include <sys/zfs_vfsops.h>
@@ -66,6 +64,7 @@ int zfsctl_lookup_objset(vfs_t *vfsp, uint64_t objsetid, zfsvfs_t **zfsvfsp);
 
 #define	ZFSCTL_INO_ROOT		0x1
 #define	ZFSCTL_INO_SNAPDIR	0x2
+#define	ZFSCTL_INO_SHARES	0x3
 
 #ifdef	__cplusplus
 }
diff --git a/module/zfs/include/sys/zfs_dir.h b/module/zfs/include/sys/zfs_dir.h
index ebb66e8ae..650315be2 100644
--- a/module/zfs/include/sys/zfs_dir.h
+++ b/module/zfs/include/sys/zfs_dir.h
@@ -19,15 +19,13 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
 #ifndef	_SYS_FS_ZFS_DIR_H
 #define	_SYS_FS_ZFS_DIR_H
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/pathname.h>
 #include <sys/dmu.h>
 #include <sys/zfs_znode.h>
@@ -59,7 +57,7 @@ extern int zfs_link_destroy(zfs_dirlock_t *, znode_t *, dmu_tx_t *, int,
 extern int zfs_dirlook(znode_t *, char *, vnode_t **, int, int *,
     pathname_t *);
 extern void zfs_mknode(znode_t *, vattr_t *, dmu_tx_t *, cred_t *,
-    uint_t, znode_t **, int, zfs_acl_t *, zfs_fuid_info_t **);
+    uint_t, znode_t **, int, zfs_acl_ids_t *);
 extern void zfs_rmnode(znode_t *);
 extern void zfs_dl_name_switch(zfs_dirlock_t *dl, char *new, char **old);
 extern boolean_t zfs_dirempty(znode_t *);
diff --git a/module/zfs/include/sys/zfs_fuid.h b/module/zfs/include/sys/zfs_fuid.h
index 810ffc81a..f81ddf4a5 100644
--- a/module/zfs/include/sys/zfs_fuid.h
+++ b/module/zfs/include/sys/zfs_fuid.h
@@ -19,15 +19,13 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
 #ifndef	_SYS_FS_ZFS_FUID_H
 #define	_SYS_FS_ZFS_FUID_H
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #ifdef _KERNEL
 #include <sys/kidmap.h>
 #include <sys/sid.h>
@@ -51,11 +49,11 @@ typedef enum {
  * Estimate space needed for one more fuid table entry.
  * for now assume its current size + 1K
  */
-#define	FUID_SIZE_ESTIMATE(z) (z->z_fuid_size + (SPA_MINBLOCKSIZE << 1))
+#define	FUID_SIZE_ESTIMATE(z) ((z)->z_fuid_size + (SPA_MINBLOCKSIZE << 1))
 
-#define	FUID_INDEX(x)	(x >> 32)
-#define	FUID_RID(x)	(x & 0xffffffff)
-#define	FUID_ENCODE(idx, rid) ((idx << 32) | rid)
+#define	FUID_INDEX(x)	((x) >> 32)
+#define	FUID_RID(x)	((x) & 0xffffffff)
+#define	FUID_ENCODE(idx, rid) (((uint64_t)(idx) << 32) | (rid))
 /*
  * FUIDs cause problems for the intent log
  * we need to replay the creation of the FUID,
@@ -104,17 +102,23 @@ struct znode;
 extern uid_t zfs_fuid_map_id(zfsvfs_t *, uint64_t, cred_t *, zfs_fuid_type_t);
 extern void zfs_fuid_destroy(zfsvfs_t *);
 extern uint64_t zfs_fuid_create_cred(zfsvfs_t *, zfs_fuid_type_t,
-    dmu_tx_t *, cred_t *, zfs_fuid_info_t **);
+    cred_t *, zfs_fuid_info_t **);
 extern uint64_t zfs_fuid_create(zfsvfs_t *, uint64_t, cred_t *, zfs_fuid_type_t,
-    dmu_tx_t *, zfs_fuid_info_t **);
-extern void zfs_fuid_map_ids(struct znode *zp, cred_t *cr, uid_t *uid,
-    uid_t *gid);
+    zfs_fuid_info_t **);
+extern void zfs_fuid_map_ids(struct znode *zp, cred_t *cr,
+    uid_t *uid, uid_t *gid);
 extern zfs_fuid_info_t *zfs_fuid_info_alloc(void);
-extern void zfs_fuid_info_free();
+extern void zfs_fuid_info_free(zfs_fuid_info_t *);
 extern boolean_t zfs_groupmember(zfsvfs_t *, uint64_t, cred_t *);
+void zfs_fuid_sync(zfsvfs_t *, dmu_tx_t *);
+extern int zfs_fuid_find_by_domain(zfsvfs_t *, const char *domain,
+    char **retdomain, boolean_t addok);
+extern const char *zfs_fuid_find_by_idx(zfsvfs_t *zfsvfs, uint32_t idx);
+extern void zfs_fuid_txhold(zfsvfs_t *zfsvfs, dmu_tx_t *tx);
 #endif
 
 char *zfs_fuid_idx_domain(avl_tree_t *, uint32_t);
+void zfs_fuid_avl_tree_create(avl_tree_t *, avl_tree_t *);
 uint64_t zfs_fuid_table_load(objset_t *, uint64_t, avl_tree_t *, avl_tree_t *);
 void zfs_fuid_table_destroy(avl_tree_t *, avl_tree_t *);
 
diff --git a/module/zfs/include/sys/zfs_ioctl.h b/module/zfs/include/sys/zfs_ioctl.h
index 1692608bb..1e9f35155 100644
--- a/module/zfs/include/sys/zfs_ioctl.h
+++ b/module/zfs/include/sys/zfs_ioctl.h
@@ -19,15 +19,13 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
 #ifndef	_SYS_ZFS_IOCTL_H
 #define	_SYS_ZFS_IOCTL_H
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/cred.h>
 #include <sys/dmu.h>
 #include <sys/zio.h>
@@ -118,7 +116,7 @@ typedef struct zinject_record {
 	uint32_t	zi_error;
 	uint64_t	zi_type;
 	uint32_t	zi_freq;
-	uint32_t	zi_pad;	/* pad out to 64 bit alignment */
+	uint32_t	zi_failfast;
 } zinject_record_t;
 
 #define	ZINJECT_NULL		0x1
@@ -162,12 +160,20 @@ typedef struct zfs_cmd {
 	uint64_t 	zc_history_len;
 	uint64_t	zc_history_offset;
 	uint64_t	zc_obj;
+	uint64_t	zc_iflags;		/* internal to zfs(7fs) */
 	zfs_share_t	zc_share;
 	dmu_objset_stats_t zc_objset_stats;
 	struct drr_begin zc_begin_record;
 	zinject_record_t zc_inject_record;
 } zfs_cmd_t;
 
+typedef struct zfs_useracct {
+	char zu_domain[256];
+	uid_t zu_rid;
+	uint32_t zu_pad;
+	uint64_t zu_space;
+} zfs_useracct_t;
+
 #define	ZVOL_MAX_MINOR	(1 << 16)
 #define	ZFS_MIN_MINOR	(ZVOL_MAX_MINOR + 1)
 
diff --git a/module/zfs/include/sys/zfs_vfsops.h b/module/zfs/include/sys/zfs_vfsops.h
index 7e0440be4..b8ed7b27f 100644
--- a/module/zfs/include/sys/zfs_vfsops.h
+++ b/module/zfs/include/sys/zfs_vfsops.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -53,6 +53,7 @@ struct zfsvfs {
 	avl_tree_t	z_fuid_domain;	/* fuid tree keyed by domain */
 	krwlock_t	z_fuid_lock;	/* fuid lock */
 	boolean_t	z_fuid_loaded;	/* fuid tables are loaded */
+	boolean_t	z_fuid_dirty;   /* need to sync fuid table ? */
 	struct zfs_fuid_info	*z_fuid_replay; /* fuid info for replay */
 	zilog_t		*z_log;		/* intent log pointer */
 	uint_t		z_acl_mode;	/* acl chmod/mode behavior */
@@ -72,8 +73,12 @@ struct zfsvfs {
 	boolean_t	z_vscan;	/* virus scan on/off */
 	boolean_t	z_use_fuids;	/* version allows fuids */
 	boolean_t	z_replay;	/* set during ZIL replay */
-	kmutex_t	z_online_recv_lock; /* recv in prog grabs as WRITER */
+	kmutex_t	z_online_recv_lock; /* held while recv in progress */
 	uint64_t	z_version;	/* ZPL version */
+	uint64_t	z_shares_dir;	/* hidden shares dir */
+	kmutex_t	z_lock;
+	uint64_t	z_userquota_obj;
+	uint64_t	z_groupquota_obj;
 #define	ZFS_OBJ_MTX_SZ	64
 	kmutex_t	z_hold_mtx[ZFS_OBJ_MTX_SZ];	/* znode hold locks */
 };
@@ -130,6 +135,17 @@ extern uint_t zfs_fsyncer_key;
 
 extern int zfs_suspend_fs(zfsvfs_t *zfsvfs, char *osname, int *mode);
 extern int zfs_resume_fs(zfsvfs_t *zfsvfs, const char *osname, int mode);
+extern int zfs_userspace_one(zfsvfs_t *zfsvfs, zfs_userquota_prop_t type,
+    const char *domain, uint64_t rid, uint64_t *valuep);
+extern int zfs_userspace_many(zfsvfs_t *zfsvfs, zfs_userquota_prop_t type,
+    uint64_t *cookiep, void *vbuf, uint64_t *bufsizep);
+extern int zfs_set_userquota(zfsvfs_t *zfsvfs, zfs_userquota_prop_t type,
+    const char *domain, uint64_t rid, uint64_t quota);
+extern boolean_t zfs_usergroup_overquota(zfsvfs_t *zfsvfs,
+    boolean_t isgroup, uint64_t fuid);
+extern int zfs_set_version(zfsvfs_t *zfsvfs, uint64_t newvers);
+extern int zfsvfs_create(const char *name, int mode, zfsvfs_t **zvp);
+extern void zfsvfs_free(zfsvfs_t *zfsvfs);
 
 #ifdef	__cplusplus
 }
diff --git a/module/zfs/include/sys/zfs_znode.h b/module/zfs/include/sys/zfs_znode.h
index 9192abcd7..69f4b50f5 100644
--- a/module/zfs/include/sys/zfs_znode.h
+++ b/module/zfs/include/sys/zfs_znode.h
@@ -93,12 +93,15 @@ extern "C" {
 
 /*
  * Special attributes for master node.
+ * "userquota@" and "groupquota@" are also valid (from
+ * zfs_userquota_prop_prefixes[]).
  */
 #define	ZFS_FSID		"FSID"
 #define	ZFS_UNLINKED_SET	"DELETE_QUEUE"
 #define	ZFS_ROOT_OBJ		"ROOT"
 #define	ZPL_VERSION_STR		"VERSION"
 #define	ZFS_FUID_TABLES		"FUID"
+#define	ZFS_SHARES_DIR		"SHARES"
 
 #define	ZFS_MAX_BLOCKSIZE	(SPA_MAXBLOCKSIZE)
 
@@ -309,7 +312,6 @@ extern int	zfs_create_op_tables();
 extern int	zfs_sync(vfs_t *vfsp, short flag, cred_t *cr);
 extern dev_t	zfs_cmpldev(uint64_t);
 extern int	zfs_get_zplprop(objset_t *os, zfs_prop_t prop, uint64_t *value);
-extern int	zfs_set_version(const char *name, uint64_t newvers);
 extern int	zfs_get_stats(objset_t *os, nvlist_t *nv);
 extern void	zfs_znode_dmu_fini(znode_t *);
 
@@ -336,6 +338,7 @@ extern void zfs_log_acl(zilog_t *zilog, dmu_tx_t *tx, znode_t *zp,
     vsecattr_t *vsecp, zfs_fuid_info_t *fuidp);
 extern void zfs_xvattr_set(znode_t *zp, xvattr_t *xvap);
 extern void zfs_upgrade(zfsvfs_t *zfsvfs, dmu_tx_t *tx);
+extern int zfs_create_share_dir(zfsvfs_t *zfsvfs, dmu_tx_t *tx);
 
 extern caddr_t zfs_map_page(page_t *, enum seg_rw);
 extern void zfs_unmap_page(page_t *, caddr_t);
diff --git a/module/zfs/include/sys/zil.h b/module/zfs/include/sys/zil.h
index b69323cfa..2aff8cd68 100644
--- a/module/zfs/include/sys/zil.h
+++ b/module/zfs/include/sys/zil.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -56,10 +56,16 @@ typedef struct zil_header {
 	uint64_t zh_replay_seq;	/* highest replayed sequence number */
 	blkptr_t zh_log;	/* log chain */
 	uint64_t zh_claim_seq;	/* highest claimed sequence number */
-	uint64_t zh_pad[5];
+	uint64_t zh_flags;	/* header flags */
+	uint64_t zh_pad[4];
 } zil_header_t;
 
 /*
+ * zh_flags bit settings
+ */
+#define	ZIL_REPLAY_NEEDED 0x1	/* replay needed - internal only */
+
+/*
  * Log block trailer - structure at the end of the header and each log block
  *
  * The zit_bt contains a zbt_cksum which for the intent log is
@@ -299,7 +305,27 @@ typedef struct {
  */
 
 /*
- * ZFS intent log transaction structure
+ * Writes are handled in three different ways:
+ *
+ * WR_INDIRECT:
+ *    In this mode, if we need to commit the write later, then the block
+ *    is immediately written into the file system (using dmu_sync),
+ *    and a pointer to the block is put into the log record.
+ *    When the txg commits the block is linked in.
+ *    This saves additionally writing the data into the log record.
+ *    There are a few requirements for this to occur:
+ *	- write is greater than zfs/zvol_immediate_write_sz
+ *	- not using slogs (as slogs are assumed to always be faster
+ *	  than writing into the main pool)
+ *	- the write occupies only one block
+ * WR_COPIED:
+ *    If we know we'll immediately be committing the
+ *    transaction (FSYNC or FDSYNC), the we allocate a larger
+ *    log record here for the data and copy the data in.
+ * WR_NEED_COPY:
+ *    Otherwise we don't allocate a buffer, and *if* we need to
+ *    flush the write later then a buffer is allocated and
+ *    we retrieve the data using the dmu.
  */
 typedef enum {
 	WR_INDIRECT,	/* indirect - a large write (dmu_sync() data */
@@ -359,9 +385,9 @@ extern uint64_t zil_itx_assign(zilog_t *zilog, itx_t *itx, dmu_tx_t *tx);
 
 extern void	zil_commit(zilog_t *zilog, uint64_t seq, uint64_t oid);
 
+extern int	zil_vdev_offline(char *osname, void *txarg);
 extern int	zil_claim(char *osname, void *txarg);
 extern int	zil_check_log_chain(char *osname, void *txarg);
-extern int	zil_clear_log_chain(char *osname, void *txarg);
 extern void	zil_sync(zilog_t *zilog, dmu_tx_t *tx);
 extern void	zil_clean(zilog_t *zilog);
 extern int	zil_is_committed(zilog_t *zilog);
diff --git a/module/zfs/include/sys/zil_impl.h b/module/zfs/include/sys/zil_impl.h
index 3f2582931..685305fb5 100644
--- a/module/zfs/include/sys/zil_impl.h
+++ b/module/zfs/include/sys/zil_impl.h
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -101,6 +101,9 @@ typedef struct zil_dva_node {
 	avl_node_t	zn_node;
 } zil_dva_node_t;
 
+#define	ZIL_MAX_LOG_DATA (SPA_MAXBLOCKSIZE - sizeof (zil_trailer_t) - \
+    sizeof (lr_write_t))
+
 #ifdef	__cplusplus
 }
 #endif
diff --git a/module/zfs/include/sys/zio.h b/module/zfs/include/sys/zio.h
index 67adc3b4c..5c51717c1 100644
--- a/module/zfs/include/sys/zio.h
+++ b/module/zfs/include/sys/zio.h
@@ -76,7 +76,7 @@ enum zio_checksum {
 	ZIO_CHECKSUM_FUNCTIONS
 };
 
-#define	ZIO_CHECKSUM_ON_VALUE	ZIO_CHECKSUM_FLETCHER_2
+#define	ZIO_CHECKSUM_ON_VALUE	ZIO_CHECKSUM_FLETCHER_4
 #define	ZIO_CHECKSUM_DEFAULT	ZIO_CHECKSUM_ON
 
 enum zio_compress {
@@ -116,30 +116,33 @@ enum zio_compress {
 #define	ZIO_PRIORITY_SCRUB		(zio_priority_table[9])
 #define	ZIO_PRIORITY_TABLE_SIZE		10
 
-#define	ZIO_FLAG_MUSTSUCCEED		0x00000
-#define	ZIO_FLAG_CANFAIL		0x00001
-#define	ZIO_FLAG_SPECULATIVE		0x00002
-#define	ZIO_FLAG_CONFIG_WRITER		0x00004
-#define	ZIO_FLAG_DONT_RETRY		0x00008
+#define	ZIO_FLAG_MUSTSUCCEED		0x000000
+#define	ZIO_FLAG_CANFAIL		0x000001
+#define	ZIO_FLAG_SPECULATIVE		0x000002
+#define	ZIO_FLAG_CONFIG_WRITER		0x000004
+#define	ZIO_FLAG_DONT_RETRY		0x000008
 
-#define	ZIO_FLAG_DONT_CACHE		0x00010
-#define	ZIO_FLAG_DONT_QUEUE		0x00020
-#define	ZIO_FLAG_DONT_AGGREGATE		0x00040
-#define	ZIO_FLAG_DONT_PROPAGATE		0x00080
+#define	ZIO_FLAG_DONT_CACHE		0x000010
+#define	ZIO_FLAG_DONT_QUEUE		0x000020
+#define	ZIO_FLAG_DONT_AGGREGATE		0x000040
+#define	ZIO_FLAG_DONT_PROPAGATE		0x000080
 
-#define	ZIO_FLAG_IO_BYPASS		0x00100
-#define	ZIO_FLAG_IO_REPAIR		0x00200
-#define	ZIO_FLAG_IO_RETRY		0x00400
-#define	ZIO_FLAG_IO_REWRITE		0x00800
+#define	ZIO_FLAG_IO_BYPASS		0x000100
+#define	ZIO_FLAG_IO_REPAIR		0x000200
+#define	ZIO_FLAG_IO_RETRY		0x000400
+#define	ZIO_FLAG_IO_REWRITE		0x000800
 
-#define	ZIO_FLAG_SELF_HEAL		0x01000
-#define	ZIO_FLAG_RESILVER		0x02000
-#define	ZIO_FLAG_SCRUB			0x04000
-#define	ZIO_FLAG_SCRUB_THREAD		0x08000
+#define	ZIO_FLAG_SELF_HEAL		0x001000
+#define	ZIO_FLAG_RESILVER		0x002000
+#define	ZIO_FLAG_SCRUB			0x004000
+#define	ZIO_FLAG_SCRUB_THREAD		0x008000
 
-#define	ZIO_FLAG_PROBE			0x10000
-#define	ZIO_FLAG_GANG_CHILD		0x20000
-#define	ZIO_FLAG_RAW			0x40000
+#define	ZIO_FLAG_PROBE			0x010000
+#define	ZIO_FLAG_GANG_CHILD		0x020000
+#define	ZIO_FLAG_RAW			0x040000
+#define	ZIO_FLAG_GODFATHER		0x080000
+
+#define	ZIO_FLAG_TRYHARD		0x100000
 
 #define	ZIO_FLAG_GANG_INHERIT		\
 	(ZIO_FLAG_CANFAIL |		\
@@ -157,7 +160,8 @@ enum zio_compress {
 	(ZIO_FLAG_GANG_INHERIT |	\
 	ZIO_FLAG_IO_REPAIR |		\
 	ZIO_FLAG_IO_RETRY |		\
-	ZIO_FLAG_PROBE)
+	ZIO_FLAG_PROBE |		\
+	ZIO_FLAG_TRYHARD)
 
 #define	ZIO_FLAG_AGG_INHERIT		\
 	(ZIO_FLAG_DONT_AGGREGATE |	\
@@ -281,7 +285,6 @@ struct zio {
 	int		io_cmd;
 	uint8_t		io_priority;
 	uint8_t		io_reexecute;
-	uint8_t		io_async_root;
 	uint8_t		io_state[ZIO_WAIT_TYPES];
 	uint64_t	io_txg;
 	spa_t		*io_spa;
@@ -324,6 +327,7 @@ struct zio {
 	int		io_child_error[ZIO_CHILD_TYPES];
 	uint64_t	io_children[ZIO_CHILD_TYPES][ZIO_WAIT_TYPES];
 	uint64_t	*io_stall;
+	zio_t		*io_gang_leader;
 	zio_gang_node_t	*io_gang_tree;
 	void		*io_executor;
 	void		*io_waiter;
@@ -415,7 +419,7 @@ extern uint8_t zio_checksum_select(uint8_t child, uint8_t parent);
 extern uint8_t zio_compress_select(uint8_t child, uint8_t parent);
 
 extern void zio_suspend(spa_t *spa, zio_t *zio);
-extern void zio_resume(spa_t *spa);
+extern int zio_resume(spa_t *spa);
 extern void zio_resume_wait(spa_t *spa);
 
 /*
@@ -435,7 +439,7 @@ extern int zio_inject_list_next(int *id, char *name, size_t buflen,
     struct zinject_record *record);
 extern int zio_clear_fault(int id);
 extern int zio_handle_fault_injection(zio_t *zio, int error);
-extern int zio_handle_device_injection(vdev_t *vd, int error);
+extern int zio_handle_device_injection(vdev_t *vd, zio_t *zio, int error);
 extern int zio_handle_label_injection(zio_t *zio, int error);
 
 #ifdef	__cplusplus
diff --git a/module/zfs/metaslab.c b/module/zfs/metaslab.c
index 412832968..77556ac5d 100644
--- a/module/zfs/metaslab.c
+++ b/module/zfs/metaslab.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -36,18 +36,35 @@ uint64_t metaslab_aliquot = 512ULL << 10;
 uint64_t metaslab_gang_bang = SPA_MAXBLOCKSIZE + 1;	/* force gang blocks */
 
 /*
+ * Minimum size which forces the dynamic allocator to change
+ * it's allocation strategy. Once the space map cannot satisfy
+ * an allocation of this size then it switches to using more
+ * aggressive strategy (i.e search by size rather than offset).
+ */
+uint64_t metaslab_df_alloc_threshold = SPA_MAXBLOCKSIZE;
+
+/*
+ * The minimum free space, in percent, which must be available
+ * in a space map to continue allocations in a first-fit fashion.
+ * Once the space_map's free space drops below this level we dynamically
+ * switch to using best-fit allocations.
+ */
+int metaslab_df_free_pct = 30;
+
+/*
  * ==========================================================================
  * Metaslab classes
  * ==========================================================================
  */
 metaslab_class_t *
-metaslab_class_create(void)
+metaslab_class_create(space_map_ops_t *ops)
 {
 	metaslab_class_t *mc;
 
 	mc = kmem_zalloc(sizeof (metaslab_class_t), KM_SLEEP);
 
 	mc->mc_rotor = NULL;
+	mc->mc_ops = ops;
 
 	return (mc);
 }
@@ -202,30 +219,14 @@ metaslab_group_sort(metaslab_group_t *mg, metaslab_t *msp, uint64_t weight)
 }
 
 /*
- * ==========================================================================
- * The first-fit block allocator
- * ==========================================================================
+ * This is a helper function that can be used by the allocator to find
+ * a suitable block to allocate. This will search the specified AVL
+ * tree looking for a block that matches the specified criteria.
  */
-static void
-metaslab_ff_load(space_map_t *sm)
-{
-	ASSERT(sm->sm_ppd == NULL);
-	sm->sm_ppd = kmem_zalloc(64 * sizeof (uint64_t), KM_SLEEP);
-}
-
-static void
-metaslab_ff_unload(space_map_t *sm)
-{
-	kmem_free(sm->sm_ppd, 64 * sizeof (uint64_t));
-	sm->sm_ppd = NULL;
-}
-
 static uint64_t
-metaslab_ff_alloc(space_map_t *sm, uint64_t size)
+metaslab_block_picker(avl_tree_t *t, uint64_t *cursor, uint64_t size,
+    uint64_t align)
 {
-	avl_tree_t *t = &sm->sm_root;
-	uint64_t align = size & -size;
-	uint64_t *cursor = (uint64_t *)sm->sm_ppd + highbit(align) - 1;
 	space_seg_t *ss, ssearch;
 	avl_index_t where;
 
@@ -254,7 +255,37 @@ metaslab_ff_alloc(space_map_t *sm, uint64_t size)
 		return (-1ULL);
 
 	*cursor = 0;
-	return (metaslab_ff_alloc(sm, size));
+	return (metaslab_block_picker(t, cursor, size, align));
+}
+
+/*
+ * ==========================================================================
+ * The first-fit block allocator
+ * ==========================================================================
+ */
+static void
+metaslab_ff_load(space_map_t *sm)
+{
+	ASSERT(sm->sm_ppd == NULL);
+	sm->sm_ppd = kmem_zalloc(64 * sizeof (uint64_t), KM_SLEEP);
+	sm->sm_pp_root = NULL;
+}
+
+static void
+metaslab_ff_unload(space_map_t *sm)
+{
+	kmem_free(sm->sm_ppd, 64 * sizeof (uint64_t));
+	sm->sm_ppd = NULL;
+}
+
+static uint64_t
+metaslab_ff_alloc(space_map_t *sm, uint64_t size)
+{
+	avl_tree_t *t = &sm->sm_root;
+	uint64_t align = size & -size;
+	uint64_t *cursor = (uint64_t *)sm->sm_ppd + highbit(align) - 1;
+
+	return (metaslab_block_picker(t, cursor, size, align));
 }
 
 /* ARGSUSED */
@@ -276,9 +307,136 @@ static space_map_ops_t metaslab_ff_ops = {
 	metaslab_ff_unload,
 	metaslab_ff_alloc,
 	metaslab_ff_claim,
-	metaslab_ff_free
+	metaslab_ff_free,
+	NULL	/* maxsize */
+};
+
+/*
+ * Dynamic block allocator -
+ * Uses the first fit allocation scheme until space get low and then
+ * adjusts to a best fit allocation method. Uses metaslab_df_alloc_threshold
+ * and metaslab_df_free_pct to determine when to switch the allocation scheme.
+ */
+
+uint64_t
+metaslab_df_maxsize(space_map_t *sm)
+{
+	avl_tree_t *t = sm->sm_pp_root;
+	space_seg_t *ss;
+
+	if (t == NULL || (ss = avl_last(t)) == NULL)
+		return (0ULL);
+
+	return (ss->ss_end - ss->ss_start);
+}
+
+static int
+metaslab_df_seg_compare(const void *x1, const void *x2)
+{
+	const space_seg_t *s1 = x1;
+	const space_seg_t *s2 = x2;
+	uint64_t ss_size1 = s1->ss_end - s1->ss_start;
+	uint64_t ss_size2 = s2->ss_end - s2->ss_start;
+
+	if (ss_size1 < ss_size2)
+		return (-1);
+	if (ss_size1 > ss_size2)
+		return (1);
+
+	if (s1->ss_start < s2->ss_start)
+		return (-1);
+	if (s1->ss_start > s2->ss_start)
+		return (1);
+
+	return (0);
+}
+
+static void
+metaslab_df_load(space_map_t *sm)
+{
+	space_seg_t *ss;
+
+	ASSERT(sm->sm_ppd == NULL);
+	sm->sm_ppd = kmem_zalloc(64 * sizeof (uint64_t), KM_SLEEP);
+
+	sm->sm_pp_root = kmem_alloc(sizeof (avl_tree_t), KM_SLEEP);
+	avl_create(sm->sm_pp_root, metaslab_df_seg_compare,
+	    sizeof (space_seg_t), offsetof(struct space_seg, ss_pp_node));
+
+	for (ss = avl_first(&sm->sm_root); ss; ss = AVL_NEXT(&sm->sm_root, ss))
+		avl_add(sm->sm_pp_root, ss);
+}
+
+static void
+metaslab_df_unload(space_map_t *sm)
+{
+	void *cookie = NULL;
+
+	kmem_free(sm->sm_ppd, 64 * sizeof (uint64_t));
+	sm->sm_ppd = NULL;
+
+	while (avl_destroy_nodes(sm->sm_pp_root, &cookie) != NULL) {
+		/* tear down the tree */
+	}
+
+	avl_destroy(sm->sm_pp_root);
+	kmem_free(sm->sm_pp_root, sizeof (avl_tree_t));
+	sm->sm_pp_root = NULL;
+}
+
+static uint64_t
+metaslab_df_alloc(space_map_t *sm, uint64_t size)
+{
+	avl_tree_t *t = &sm->sm_root;
+	uint64_t align = size & -size;
+	uint64_t *cursor = (uint64_t *)sm->sm_ppd + highbit(align) - 1;
+	uint64_t max_size = metaslab_df_maxsize(sm);
+	int free_pct = sm->sm_space * 100 / sm->sm_size;
+
+	ASSERT(MUTEX_HELD(sm->sm_lock));
+	ASSERT3U(avl_numnodes(&sm->sm_root), ==, avl_numnodes(sm->sm_pp_root));
+
+	if (max_size < size)
+		return (-1ULL);
+
+	/*
+	 * If we're running low on space switch to using the size
+	 * sorted AVL tree (best-fit).
+	 */
+	if (max_size < metaslab_df_alloc_threshold ||
+	    free_pct < metaslab_df_free_pct) {
+		t = sm->sm_pp_root;
+		*cursor = 0;
+	}
+
+	return (metaslab_block_picker(t, cursor, size, 1ULL));
+}
+
+/* ARGSUSED */
+static void
+metaslab_df_claim(space_map_t *sm, uint64_t start, uint64_t size)
+{
+	/* No need to update cursor */
+}
+
+/* ARGSUSED */
+static void
+metaslab_df_free(space_map_t *sm, uint64_t start, uint64_t size)
+{
+	/* No need to update cursor */
+}
+
+static space_map_ops_t metaslab_df_ops = {
+	metaslab_df_load,
+	metaslab_df_unload,
+	metaslab_df_alloc,
+	metaslab_df_claim,
+	metaslab_df_free,
+	metaslab_df_maxsize
 };
 
+space_map_ops_t *zfs_metaslab_ops = &metaslab_df_ops;
+
 /*
  * ==========================================================================
  * Metaslabs
@@ -414,20 +572,28 @@ metaslab_weight(metaslab_t *msp)
 }
 
 static int
-metaslab_activate(metaslab_t *msp, uint64_t activation_weight)
+metaslab_activate(metaslab_t *msp, uint64_t activation_weight, uint64_t size)
 {
 	space_map_t *sm = &msp->ms_map;
+	space_map_ops_t *sm_ops = msp->ms_group->mg_class->mc_ops;
 
 	ASSERT(MUTEX_HELD(&msp->ms_lock));
 
 	if ((msp->ms_weight & METASLAB_ACTIVE_MASK) == 0) {
-		int error = space_map_load(sm, &metaslab_ff_ops,
-		    SM_FREE, &msp->ms_smo,
+		int error = space_map_load(sm, sm_ops, SM_FREE, &msp->ms_smo,
 		    msp->ms_group->mg_vd->vdev_spa->spa_meta_objset);
 		if (error) {
 			metaslab_group_sort(msp->ms_group, msp, 0);
 			return (error);
 		}
+
+		/*
+		 * If we were able to load the map then make sure
+		 * that this map is still able to satisfy our request.
+		 */
+		if (msp->ms_weight < size)
+			return (ENOSPC);
+
 		metaslab_group_sort(msp->ms_group, msp,
 		    msp->ms_weight | activation_weight);
 	}
@@ -636,11 +802,16 @@ metaslab_group_alloc(metaslab_group_t *mg, uint64_t size, uint64_t txg,
 	int i;
 
 	activation_weight = METASLAB_WEIGHT_PRIMARY;
-	for (i = 0; i < d; i++)
-		if (DVA_GET_VDEV(&dva[i]) == mg->mg_vd->vdev_id)
+	for (i = 0; i < d; i++) {
+		if (DVA_GET_VDEV(&dva[i]) == mg->mg_vd->vdev_id) {
 			activation_weight = METASLAB_WEIGHT_SECONDARY;
+			break;
+		}
+	}
 
 	for (;;) {
+		boolean_t was_active;
+
 		mutex_enter(&mg->mg_lock);
 		for (msp = avl_first(t); msp; msp = AVL_NEXT(t, msp)) {
 			if (msp->ms_weight < size) {
@@ -648,6 +819,7 @@ metaslab_group_alloc(metaslab_group_t *mg, uint64_t size, uint64_t txg,
 				return (-1ULL);
 			}
 
+			was_active = msp->ms_weight & METASLAB_ACTIVE_MASK;
 			if (activation_weight == METASLAB_WEIGHT_PRIMARY)
 				break;
 
@@ -673,7 +845,9 @@ metaslab_group_alloc(metaslab_group_t *mg, uint64_t size, uint64_t txg,
 		 * another thread may have changed the weight while we
 		 * were blocked on the metaslab lock.
 		 */
-		if (msp->ms_weight < size) {
+		if (msp->ms_weight < size || (was_active &&
+		    !(msp->ms_weight & METASLAB_ACTIVE_MASK) &&
+		    activation_weight == METASLAB_WEIGHT_PRIMARY)) {
 			mutex_exit(&msp->ms_lock);
 			continue;
 		}
@@ -686,7 +860,7 @@ metaslab_group_alloc(metaslab_group_t *mg, uint64_t size, uint64_t txg,
 			continue;
 		}
 
-		if (metaslab_activate(msp, activation_weight) != 0) {
+		if (metaslab_activate(msp, activation_weight, size) != 0) {
 			mutex_exit(&msp->ms_lock);
 			continue;
 		}
@@ -869,7 +1043,7 @@ next:
 		goto top;
 	}
 
-	if (!zio_lock) {
+	if (!allocatable && !zio_lock) {
 		dshift = 3;
 		zio_lock = B_TRUE;
 		goto top;
@@ -955,7 +1129,7 @@ metaslab_claim_dva(spa_t *spa, const dva_t *dva, uint64_t txg)
 
 	mutex_enter(&msp->ms_lock);
 
-	error = metaslab_activate(msp, METASLAB_WEIGHT_SECONDARY);
+	error = metaslab_activate(msp, METASLAB_WEIGHT_SECONDARY, 0);
 	if (error || txg == 0) {	/* txg == 0 indicates dry run */
 		mutex_exit(&msp->ms_lock);
 		return (error);
diff --git a/module/zfs/spa.c b/module/zfs/spa.c
index df1b7e125..6a95b399b 100644
--- a/module/zfs/spa.c
+++ b/module/zfs/spa.c
@@ -59,6 +59,7 @@
 #include <sys/systeminfo.h>
 #include <sys/sunddi.h>
 #include <sys/spa_boot.h>
+#include <sys/zfs_ioctl.h>
 
 #ifdef	_KERNEL
 #include <sys/zone.h>
@@ -67,16 +68,44 @@
 #include "zfs_prop.h"
 #include "zfs_comutil.h"
 
-int zio_taskq_threads[ZIO_TYPES][ZIO_TASKQ_TYPES] = {
-	/*	ISSUE	INTR					*/
-	{	1,	1	},	/* ZIO_TYPE_NULL	*/
-	{	1,	8	},	/* ZIO_TYPE_READ	*/
-	{	8,	1	},	/* ZIO_TYPE_WRITE	*/
-	{	1,	1	},	/* ZIO_TYPE_FREE	*/
-	{	1,	1	},	/* ZIO_TYPE_CLAIM	*/
-	{	1,	1	},	/* ZIO_TYPE_IOCTL	*/
+enum zti_modes {
+	zti_mode_fixed,			/* value is # of threads (min 1) */
+	zti_mode_online_percent,	/* value is % of online CPUs */
+	zti_mode_tune,			/* fill from zio_taskq_tune_* */
+	zti_nmodes
 };
 
+#define	ZTI_THREAD_FIX(n)	{ zti_mode_fixed, (n) }
+#define	ZTI_THREAD_PCT(n)	{ zti_mode_online_percent, (n) }
+#define	ZTI_THREAD_TUNE		{ zti_mode_tune, 0 }
+
+#define	ZTI_THREAD_ONE		ZTI_THREAD_FIX(1)
+
+typedef struct zio_taskq_info {
+	const char *zti_name;
+	struct {
+		enum zti_modes zti_mode;
+		uint_t zti_value;
+	} zti_nthreads[ZIO_TASKQ_TYPES];
+} zio_taskq_info_t;
+
+static const char *const zio_taskq_types[ZIO_TASKQ_TYPES] = {
+				"issue",		"intr"
+};
+
+const zio_taskq_info_t zio_taskqs[ZIO_TYPES] = {
+	/*			ISSUE			INTR		*/
+	{ "spa_zio_null",	{ ZTI_THREAD_ONE,	ZTI_THREAD_ONE } },
+	{ "spa_zio_read",	{ ZTI_THREAD_FIX(8),	ZTI_THREAD_TUNE } },
+	{ "spa_zio_write",	{ ZTI_THREAD_TUNE,	ZTI_THREAD_FIX(8) } },
+	{ "spa_zio_free",	{ ZTI_THREAD_ONE,	ZTI_THREAD_ONE } },
+	{ "spa_zio_claim",	{ ZTI_THREAD_ONE,	ZTI_THREAD_ONE } },
+	{ "spa_zio_ioctl",	{ ZTI_THREAD_ONE,	ZTI_THREAD_ONE } },
+};
+
+enum zti_modes zio_taskq_tune_mode = zti_mode_online_percent;
+uint_t zio_taskq_tune_value = 80;	/* #threads = 80% of # online CPUs */
+
 static void spa_sync_props(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx);
 static boolean_t spa_has_active_shared_spare(spa_t *spa);
 
@@ -304,12 +333,18 @@ spa_prop_validate(spa_t *spa, nvlist_t *props)
 		case ZPOOL_PROP_DELEGATION:
 		case ZPOOL_PROP_AUTOREPLACE:
 		case ZPOOL_PROP_LISTSNAPS:
+		case ZPOOL_PROP_AUTOEXPAND:
 			error = nvpair_value_uint64(elem, &intval);
 			if (!error && intval > 1)
 				error = EINVAL;
 			break;
 
 		case ZPOOL_PROP_BOOTFS:
+			/*
+			 * If the pool version is less than SPA_VERSION_BOOTFS,
+			 * or the pool is still being created (version == 0),
+			 * the bootfs property cannot be set.
+			 */
 			if (spa_version(spa) < SPA_VERSION_BOOTFS) {
 				error = ENOTSUP;
 				break;
@@ -541,14 +576,50 @@ spa_activate(spa_t *spa, int mode)
 	spa->spa_state = POOL_STATE_ACTIVE;
 	spa->spa_mode = mode;
 
-	spa->spa_normal_class = metaslab_class_create();
-	spa->spa_log_class = metaslab_class_create();
+	spa->spa_normal_class = metaslab_class_create(zfs_metaslab_ops);
+	spa->spa_log_class = metaslab_class_create(zfs_metaslab_ops);
 
 	for (int t = 0; t < ZIO_TYPES; t++) {
+		const zio_taskq_info_t *ztip = &zio_taskqs[t];
 		for (int q = 0; q < ZIO_TASKQ_TYPES; q++) {
-			spa->spa_zio_taskq[t][q] = taskq_create("spa_zio",
-			    zio_taskq_threads[t][q], maxclsyspri, 50,
-			    INT_MAX, TASKQ_PREPOPULATE);
+			enum zti_modes mode = ztip->zti_nthreads[q].zti_mode;
+			uint_t value = ztip->zti_nthreads[q].zti_value;
+			char name[32];
+
+			(void) snprintf(name, sizeof (name),
+			    "%s_%s", ztip->zti_name, zio_taskq_types[q]);
+
+			if (mode == zti_mode_tune) {
+				mode = zio_taskq_tune_mode;
+				value = zio_taskq_tune_value;
+				if (mode == zti_mode_tune)
+					mode = zti_mode_online_percent;
+			}
+
+			switch (mode) {
+			case zti_mode_fixed:
+				ASSERT3U(value, >=, 1);
+				value = MAX(value, 1);
+
+				spa->spa_zio_taskq[t][q] = taskq_create(name,
+				    value, maxclsyspri, 50, INT_MAX,
+				    TASKQ_PREPOPULATE);
+				break;
+
+			case zti_mode_online_percent:
+				spa->spa_zio_taskq[t][q] = taskq_create(name,
+				    value, maxclsyspri, 50, INT_MAX,
+				    TASKQ_PREPOPULATE | TASKQ_THREADS_CPU_PCT);
+				break;
+
+			case zti_mode_tune:
+			default:
+				panic("unrecognized mode for "
+				    "zio_taskqs[%u]->zti_nthreads[%u] (%u:%u) "
+				    "in spa_activate()",
+				    t, q, mode, value);
+				break;
+			}
 		}
 	}
 
@@ -577,7 +648,7 @@ spa_deactivate(spa_t *spa)
 	ASSERT(spa->spa_sync_on == B_FALSE);
 	ASSERT(spa->spa_dsl_pool == NULL);
 	ASSERT(spa->spa_root_vdev == NULL);
-
+	ASSERT(spa->spa_async_zio_root == NULL);
 	ASSERT(spa->spa_state != POOL_STATE_UNINITIALIZED);
 
 	txg_list_destroy(&spa->spa_vdev_txg_list);
@@ -621,7 +692,7 @@ spa_config_parse(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent,
     uint_t id, int atype)
 {
 	nvlist_t **child;
-	uint_t c, children;
+	uint_t children;
 	int error;
 
 	if ((error = vdev_alloc(spa, vdp, nv, parent, id, atype)) != 0)
@@ -642,7 +713,7 @@ spa_config_parse(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent,
 		return (EINVAL);
 	}
 
-	for (c = 0; c < children; c++) {
+	for (int c = 0; c < children; c++) {
 		vdev_t *vd;
 		if ((error = spa_config_parse(spa, &vd, child[c], *vdp, c,
 		    atype)) != 0) {
@@ -683,10 +754,10 @@ spa_unload(spa_t *spa)
 	/*
 	 * Wait for any outstanding async I/O to complete.
 	 */
-	mutex_enter(&spa->spa_async_root_lock);
-	while (spa->spa_async_root_count != 0)
-		cv_wait(&spa->spa_async_root_cv, &spa->spa_async_root_lock);
-	mutex_exit(&spa->spa_async_root_lock);
+	if (spa->spa_async_zio_root != NULL) {
+		(void) zio_wait(spa->spa_async_zio_root);
+		spa->spa_async_zio_root = NULL;
+	}
 
 	/*
 	 * Close the dsl pool.
@@ -828,6 +899,7 @@ spa_load_spares(spa_t *spa)
 		}
 
 		vd->vdev_top = vd;
+		vd->vdev_aux = &spa->spa_spares;
 
 		if (vdev_open(vd) != 0)
 			continue;
@@ -869,7 +941,7 @@ spa_load_l2cache(spa_t *spa)
 	nvlist_t **l2cache;
 	uint_t nl2cache;
 	int i, j, oldnvdevs;
-	uint64_t guid, size;
+	uint64_t guid;
 	vdev_t *vd, **oldvdevs, **newvdevs;
 	spa_aux_vdev_t *sav = &spa->spa_l2cache;
 
@@ -933,12 +1005,8 @@ spa_load_l2cache(spa_t *spa)
 
 			(void) vdev_validate_aux(vd);
 
-			if (!vdev_is_dead(vd)) {
-				size = vdev_get_rsize(vd);
-				l2arc_add_vdev(spa, vd,
-				    VDEV_LABEL_START_SIZE,
-				    size - VDEV_LABEL_START_SIZE);
-			}
+			if (!vdev_is_dead(vd))
+				l2arc_add_vdev(spa, vd);
 		}
 	}
 
@@ -1001,7 +1069,8 @@ load_nvlist(spa_t *spa, uint64_t obj, nvlist_t **value)
 	dmu_buf_rele(db, FTAG);
 
 	packed = kmem_alloc(nvsize, KM_SLEEP);
-	error = dmu_read(spa->spa_meta_objset, obj, 0, nvsize, packed);
+	error = dmu_read(spa->spa_meta_objset, obj, 0, nvsize, packed,
+	    DMU_READ_PREFETCH);
 	if (error == 0)
 		error = nvlist_unpack(packed, nvsize, value, 0);
 	kmem_free(packed, nvsize);
@@ -1016,9 +1085,7 @@ load_nvlist(spa_t *spa, uint64_t obj, nvlist_t **value)
 static void
 spa_check_removed(vdev_t *vd)
 {
-	int c;
-
-	for (c = 0; c < vd->vdev_children; c++)
+	for (int c = 0; c < vd->vdev_children; c++)
 		spa_check_removed(vd->vdev_child[c]);
 
 	if (vd->vdev_ops->vdev_op_leaf && vdev_is_dead(vd)) {
@@ -1028,6 +1095,33 @@ spa_check_removed(vdev_t *vd)
 }
 
 /*
+ * Load the slog device state from the config object since it's possible
+ * that the label does not contain the most up-to-date information.
+ */
+void
+spa_load_log_state(spa_t *spa)
+{
+	nvlist_t *nv, *nvroot, **child;
+	uint64_t is_log;
+	uint_t children;
+	vdev_t *rvd = spa->spa_root_vdev;
+
+	VERIFY(load_nvlist(spa, spa->spa_config_object, &nv) == 0);
+	VERIFY(nvlist_lookup_nvlist(nv, ZPOOL_CONFIG_VDEV_TREE, &nvroot) == 0);
+	VERIFY(nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_CHILDREN,
+	    &child, &children) == 0);
+
+	for (int c = 0; c < children; c++) {
+		vdev_t *tvd = rvd->vdev_child[c];
+
+		if (nvlist_lookup_uint64(child[c], ZPOOL_CONFIG_IS_LOG,
+		    &is_log) == 0 && is_log)
+			vdev_load_log_state(tvd, child[c]);
+	}
+	nvlist_free(nv);
+}
+
+/*
  * Check for missing log devices
  */
 int
@@ -1043,13 +1137,7 @@ spa_check_logs(spa_t *spa)
 			return (1);
 		}
 		break;
-
-	case SPA_LOG_CLEAR:
-		(void) dmu_objset_find(spa->spa_name, zil_clear_log_chain, NULL,
-		    DS_FIND_CHILDREN);
-		break;
 	}
-	spa->spa_log_state = SPA_LOG_GOOD;
 	return (0);
 }
 
@@ -1107,6 +1195,12 @@ spa_load(spa_t *spa, nvlist_t *config, spa_load_state_t state, int mosconfig)
 	spa->spa_load_guid = pool_guid;
 
 	/*
+	 * Create "The Godfather" zio to hold all async IOs
+	 */
+	spa->spa_async_zio_root = zio_root(spa, NULL, NULL,
+	    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | ZIO_FLAG_GODFATHER);
+
+	/*
 	 * Parse the configuration into a vdev tree.  We explicitly set the
 	 * value that will be returned by spa_version() since parsing the
 	 * configuration requires knowing the version number.
@@ -1132,16 +1226,19 @@ spa_load(spa_t *spa, nvlist_t *config, spa_load_state_t state, int mosconfig)
 		goto out;
 
 	/*
-	 * Validate the labels for all leaf vdevs.  We need to grab the config
-	 * lock because all label I/O is done with ZIO_FLAG_CONFIG_WRITER.
+	 * We need to validate the vdev labels against the configuration that
+	 * we have in hand, which is dependent on the setting of mosconfig. If
+	 * mosconfig is true then we're validating the vdev labels based on
+	 * that config. Otherwise, we're validating against the cached config
+	 * (zpool.cache) that was read when we loaded the zfs module, and then
+	 * later we will recursively call spa_load() and validate against
+	 * the vdev config.
 	 */
-	if (mosconfig) {
-		spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
-		error = vdev_validate(rvd);
-		spa_config_exit(spa, SCL_ALL, FTAG);
-		if (error != 0)
-			goto out;
-	}
+	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+	error = vdev_validate(rvd);
+	spa_config_exit(spa, SCL_ALL, FTAG);
+	if (error != 0)
+		goto out;
 
 	if (rvd->vdev_state <= VDEV_STATE_CANT_OPEN) {
 		error = ENXIO;
@@ -1372,6 +1469,8 @@ spa_load(spa_t *spa, nvlist_t *config, spa_load_state_t state, int mosconfig)
 		spa_config_exit(spa, SCL_ALL, FTAG);
 	}
 
+	spa_load_log_state(spa);
+
 	if (spa_check_logs(spa)) {
 		vdev_set_state(rvd, B_TRUE, VDEV_STATE_CANT_OPEN,
 		    VDEV_AUX_BAD_LOG);
@@ -1410,6 +1509,10 @@ spa_load(spa_t *spa, nvlist_t *config, spa_load_state_t state, int mosconfig)
 		    spa->spa_pool_props_object,
 		    zpool_prop_to_name(ZPOOL_PROP_FAILUREMODE),
 		    sizeof (uint64_t), 1, &spa->spa_failmode);
+		(void) zap_lookup(spa->spa_meta_objset,
+		    spa->spa_pool_props_object,
+		    zpool_prop_to_name(ZPOOL_PROP_AUTOEXPAND),
+		    sizeof (uint64_t), 1, &spa->spa_autoexpand);
 	}
 
 	/*
@@ -1459,6 +1562,7 @@ spa_load(spa_t *spa, nvlist_t *config, spa_load_state_t state, int mosconfig)
 		    zil_claim, tx, DS_FIND_CHILDREN);
 		dmu_tx_commit(tx);
 
+		spa->spa_log_state = SPA_LOG_GOOD;
 		spa->spa_sync_on = B_TRUE;
 		txg_sync_start(spa->spa_dsl_pool);
 
@@ -1646,6 +1750,8 @@ spa_add_spares(spa_t *spa, nvlist_t *config)
 	uint_t vsc;
 	uint64_t pool;
 
+	ASSERT(spa_config_held(spa, SCL_CONFIG, RW_READER));
+
 	if (spa->spa_spares.sav_count == 0)
 		return;
 
@@ -1693,11 +1799,11 @@ spa_add_l2cache(spa_t *spa, nvlist_t *config)
 	vdev_stat_t *vs;
 	uint_t vsc;
 
+	ASSERT(spa_config_held(spa, SCL_CONFIG, RW_READER));
+
 	if (spa->spa_l2cache.sav_count == 0)
 		return;
 
-	spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
-
 	VERIFY(nvlist_lookup_nvlist(config,
 	    ZPOOL_CONFIG_VDEV_TREE, &nvroot) == 0);
 	VERIFY(nvlist_lookup_nvlist_array(spa->spa_l2cache.sav_config,
@@ -1731,8 +1837,6 @@ spa_add_l2cache(spa_t *spa, nvlist_t *config)
 			vdev_get_stats(vd, vs);
 		}
 	}
-
-	spa_config_exit(spa, SCL_CONFIG, FTAG);
 }
 
 int
@@ -1744,16 +1848,27 @@ spa_get_stats(const char *name, nvlist_t **config, char *altroot, size_t buflen)
 	*config = NULL;
 	error = spa_open_common(name, &spa, FTAG, config);
 
-	if (spa && *config != NULL) {
-		VERIFY(nvlist_add_uint64(*config, ZPOOL_CONFIG_ERRCOUNT,
-		    spa_get_errlog_size(spa)) == 0);
+	if (spa != NULL) {
+		/*
+		 * This still leaves a window of inconsistency where the spares
+		 * or l2cache devices could change and the config would be
+		 * self-inconsistent.
+		 */
+		spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
 
-		if (spa_suspended(spa))
+		if (*config != NULL) {
 			VERIFY(nvlist_add_uint64(*config,
-			    ZPOOL_CONFIG_SUSPENDED, spa->spa_failmode) == 0);
+			    ZPOOL_CONFIG_ERRCOUNT,
+			    spa_get_errlog_size(spa)) == 0);
+
+			if (spa_suspended(spa))
+				VERIFY(nvlist_add_uint64(*config,
+				    ZPOOL_CONFIG_SUSPENDED,
+				    spa->spa_failmode) == 0);
 
-		spa_add_spares(spa, *config);
-		spa_add_l2cache(spa, *config);
+			spa_add_spares(spa, *config);
+			spa_add_l2cache(spa, *config);
+		}
 	}
 
 	/*
@@ -1775,8 +1890,10 @@ spa_get_stats(const char *name, nvlist_t **config, char *altroot, size_t buflen)
 		}
 	}
 
-	if (spa != NULL)
+	if (spa != NULL) {
+		spa_config_exit(spa, SCL_CONFIG, FTAG);
 		spa_close(spa, FTAG);
+	}
 
 	return (error);
 }
@@ -1969,7 +2086,7 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
 	vdev_t *rvd;
 	dsl_pool_t *dp;
 	dmu_tx_t *tx;
-	int c, error = 0;
+	int error = 0;
 	uint64_t txg = TXG_INITIAL;
 	nvlist_t **spares, **l2cache;
 	uint_t nspares, nl2cache;
@@ -1995,7 +2112,6 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
 	spa->spa_uberblock.ub_txg = txg - 1;
 
 	if (props && (error = spa_prop_validate(spa, props))) {
-		spa_unload(spa);
 		spa_deactivate(spa);
 		spa_remove(spa);
 		mutex_exit(&spa_namespace_lock);
@@ -2010,6 +2126,12 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
 	spa->spa_ubsync = spa->spa_uberblock;
 
 	/*
+	 * Create "The Godfather" zio to hold all async IOs
+	 */
+	spa->spa_async_zio_root = zio_root(spa, NULL, NULL,
+	    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE | ZIO_FLAG_GODFATHER);
+
+	/*
 	 * Create the root vdev.
 	 */
 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
@@ -2026,9 +2148,10 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
 	    (error = vdev_create(rvd, txg, B_FALSE)) == 0 &&
 	    (error = spa_validate_aux(spa, nvroot, txg,
 	    VDEV_ALLOC_ADD)) == 0) {
-		for (c = 0; c < rvd->vdev_children; c++)
-			vdev_init(rvd->vdev_child[c], txg);
-		vdev_config_dirty(rvd);
+		for (int c = 0; c < rvd->vdev_children; c++) {
+			vdev_metaslab_set_size(rvd->vdev_child[c]);
+			vdev_expand(rvd->vdev_child[c], txg);
+		}
 	}
 
 	spa_config_exit(spa, SCL_ALL, FTAG);
@@ -2127,6 +2250,7 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
 	spa->spa_bootfs = zpool_prop_default_numeric(ZPOOL_PROP_BOOTFS);
 	spa->spa_delegation = zpool_prop_default_numeric(ZPOOL_PROP_DELEGATION);
 	spa->spa_failmode = zpool_prop_default_numeric(ZPOOL_PROP_FAILUREMODE);
+	spa->spa_autoexpand = zpool_prop_default_numeric(ZPOOL_PROP_AUTOEXPAND);
 	if (props != NULL) {
 		spa_configfile_set(spa, props, B_FALSE);
 		spa_sync_props(spa, props, CRED(), tx);
@@ -2155,17 +2279,239 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
 	return (0);
 }
 
+#ifdef _KERNEL
 /*
- * Import the given pool into the system.  We set up the necessary spa_t and
- * then call spa_load() to do the dirty work.
+ * Get the root pool information from the root disk, then import the root pool
+ * during the system boot up time.
  */
-static int
-spa_import_common(const char *pool, nvlist_t *config, nvlist_t *props,
-    boolean_t isroot, boolean_t allowfaulted)
+extern int vdev_disk_read_rootlabel(char *, char *, nvlist_t **);
+
+static nvlist_t *
+spa_generate_rootconf(char *devpath, char *devid, uint64_t *guid)
+{
+	nvlist_t *config;
+	nvlist_t *nvtop, *nvroot;
+	uint64_t pgid;
+
+	if (vdev_disk_read_rootlabel(devpath, devid, &config) != 0)
+		return (NULL);
+
+	/*
+	 * Add this top-level vdev to the child array.
+	 */
+	VERIFY(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE,
+	    &nvtop) == 0);
+	VERIFY(nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_GUID,
+	    &pgid) == 0);
+	VERIFY(nvlist_lookup_uint64(config, ZPOOL_CONFIG_GUID, guid) == 0);
+
+	/*
+	 * Put this pool's top-level vdevs into a root vdev.
+	 */
+	VERIFY(nvlist_alloc(&nvroot, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+	VERIFY(nvlist_add_string(nvroot, ZPOOL_CONFIG_TYPE,
+	    VDEV_TYPE_ROOT) == 0);
+	VERIFY(nvlist_add_uint64(nvroot, ZPOOL_CONFIG_ID, 0ULL) == 0);
+	VERIFY(nvlist_add_uint64(nvroot, ZPOOL_CONFIG_GUID, pgid) == 0);
+	VERIFY(nvlist_add_nvlist_array(nvroot, ZPOOL_CONFIG_CHILDREN,
+	    &nvtop, 1) == 0);
+
+	/*
+	 * Replace the existing vdev_tree with the new root vdev in
+	 * this pool's configuration (remove the old, add the new).
+	 */
+	VERIFY(nvlist_add_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, nvroot) == 0);
+	nvlist_free(nvroot);
+	return (config);
+}
+
+/*
+ * Walk the vdev tree and see if we can find a device with "better"
+ * configuration. A configuration is "better" if the label on that
+ * device has a more recent txg.
+ */
+static void
+spa_alt_rootvdev(vdev_t *vd, vdev_t **avd, uint64_t *txg)
+{
+	for (int c = 0; c < vd->vdev_children; c++)
+		spa_alt_rootvdev(vd->vdev_child[c], avd, txg);
+
+	if (vd->vdev_ops->vdev_op_leaf) {
+		nvlist_t *label;
+		uint64_t label_txg;
+
+		if (vdev_disk_read_rootlabel(vd->vdev_physpath, vd->vdev_devid,
+		    &label) != 0)
+			return;
+
+		VERIFY(nvlist_lookup_uint64(label, ZPOOL_CONFIG_POOL_TXG,
+		    &label_txg) == 0);
+
+		/*
+		 * Do we have a better boot device?
+		 */
+		if (label_txg > *txg) {
+			*txg = label_txg;
+			*avd = vd;
+		}
+		nvlist_free(label);
+	}
+}
+
+/*
+ * Import a root pool.
+ *
+ * For x86. devpath_list will consist of devid and/or physpath name of
+ * the vdev (e.g. "id1,sd@SSEAGATE..." or "/pci@1f,0/ide@d/disk@0,0:a").
+ * The GRUB "findroot" command will return the vdev we should boot.
+ *
+ * For Sparc, devpath_list consists the physpath name of the booting device
+ * no matter the rootpool is a single device pool or a mirrored pool.
+ * e.g.
+ *	"/pci@1f,0/ide@d/disk@0,0:a"
+ */
+int
+spa_import_rootpool(char *devpath, char *devid)
+{
+	spa_t *spa;
+	vdev_t *rvd, *bvd, *avd = NULL;
+	nvlist_t *config, *nvtop;
+	uint64_t guid, txg;
+	char *pname;
+	int error;
+
+	/*
+	 * Read the label from the boot device and generate a configuration.
+	 */
+	if ((config = spa_generate_rootconf(devpath, devid, &guid)) == NULL) {
+		cmn_err(CE_NOTE, "Can not read the pool label from '%s'",
+		    devpath);
+		return (EIO);
+	}
+
+	VERIFY(nvlist_lookup_string(config, ZPOOL_CONFIG_POOL_NAME,
+	    &pname) == 0);
+	VERIFY(nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_TXG, &txg) == 0);
+
+	mutex_enter(&spa_namespace_lock);
+	if ((spa = spa_lookup(pname)) != NULL) {
+		/*
+		 * Remove the existing root pool from the namespace so that we
+		 * can replace it with the correct config we just read in.
+		 */
+		spa_remove(spa);
+	}
+
+	spa = spa_add(pname, NULL);
+	spa->spa_is_root = B_TRUE;
+
+	/*
+	 * Build up a vdev tree based on the boot device's label config.
+	 */
+	VERIFY(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE,
+	    &nvtop) == 0);
+	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+	error = spa_config_parse(spa, &rvd, nvtop, NULL, 0,
+	    VDEV_ALLOC_ROOTPOOL);
+	spa_config_exit(spa, SCL_ALL, FTAG);
+	if (error) {
+		mutex_exit(&spa_namespace_lock);
+		nvlist_free(config);
+		cmn_err(CE_NOTE, "Can not parse the config for pool '%s'",
+		    pname);
+		return (error);
+	}
+
+	/*
+	 * Get the boot vdev.
+	 */
+	if ((bvd = vdev_lookup_by_guid(rvd, guid)) == NULL) {
+		cmn_err(CE_NOTE, "Can not find the boot vdev for guid %llu",
+		    (u_longlong_t)guid);
+		error = ENOENT;
+		goto out;
+	}
+
+	/*
+	 * Determine if there is a better boot device.
+	 */
+	avd = bvd;
+	spa_alt_rootvdev(rvd, &avd, &txg);
+	if (avd != bvd) {
+		cmn_err(CE_NOTE, "The boot device is 'degraded'. Please "
+		    "try booting from '%s'", avd->vdev_path);
+		error = EINVAL;
+		goto out;
+	}
+
+	/*
+	 * If the boot device is part of a spare vdev then ensure that
+	 * we're booting off the active spare.
+	 */
+	if (bvd->vdev_parent->vdev_ops == &vdev_spare_ops &&
+	    !bvd->vdev_isspare) {
+		cmn_err(CE_NOTE, "The boot device is currently spared. Please "
+		    "try booting from '%s'",
+		    bvd->vdev_parent->vdev_child[1]->vdev_path);
+		error = EINVAL;
+		goto out;
+	}
+
+	VERIFY(nvlist_dup(config, &spa->spa_config, 0) == 0);
+	error = 0;
+out:
+	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
+	vdev_free(rvd);
+	spa_config_exit(spa, SCL_ALL, FTAG);
+	mutex_exit(&spa_namespace_lock);
+
+	nvlist_free(config);
+	return (error);
+}
+
+#endif
+
+/*
+ * Take a pool and insert it into the namespace as if it had been loaded at
+ * boot.
+ */
+int
+spa_import_verbatim(const char *pool, nvlist_t *config, nvlist_t *props)
 {
 	spa_t *spa;
 	char *altroot = NULL;
-	int error, loaderr;
+
+	mutex_enter(&spa_namespace_lock);
+	if (spa_lookup(pool) != NULL) {
+		mutex_exit(&spa_namespace_lock);
+		return (EEXIST);
+	}
+
+	(void) nvlist_lookup_string(props,
+	    zpool_prop_to_name(ZPOOL_PROP_ALTROOT), &altroot);
+	spa = spa_add(pool, altroot);
+
+	VERIFY(nvlist_dup(config, &spa->spa_config, 0) == 0);
+
+	if (props != NULL)
+		spa_configfile_set(spa, props, B_FALSE);
+
+	spa_config_sync(spa, B_FALSE, B_TRUE);
+
+	mutex_exit(&spa_namespace_lock);
+
+	return (0);
+}
+
+/*
+ * Import a non-root pool into the system.
+ */
+int
+spa_import(const char *pool, nvlist_t *config, nvlist_t *props)
+{
+	spa_t *spa;
+	char *altroot = NULL;
+	int error;
 	nvlist_t *nvroot;
 	nvlist_t **spares, **l2cache;
 	uint_t nspares, nl2cache;
@@ -2175,18 +2521,8 @@ spa_import_common(const char *pool, nvlist_t *config, nvlist_t *props,
 	 */
 	mutex_enter(&spa_namespace_lock);
 	if ((spa = spa_lookup(pool)) != NULL) {
-		if (isroot) {
-			/*
-			 * Remove the existing root pool from the
-			 * namespace so that we can replace it with
-			 * the correct config we just read in.
-			 */
-			ASSERT(spa->spa_state == POOL_STATE_UNINITIALIZED);
-			spa_remove(spa);
-		} else {
-			mutex_exit(&spa_namespace_lock);
-			return (EEXIST);
-		}
+		mutex_exit(&spa_namespace_lock);
+		return (EEXIST);
 	}
 
 	/*
@@ -2197,29 +2533,29 @@ spa_import_common(const char *pool, nvlist_t *config, nvlist_t *props,
 	spa = spa_add(pool, altroot);
 	spa_activate(spa, spa_mode_global);
 
-	if (allowfaulted)
-		spa->spa_import_faulted = B_TRUE;
-	spa->spa_is_root = isroot;
+	/*
+	 * Don't start async tasks until we know everything is healthy.
+	 */
+	spa_async_suspend(spa);
 
 	/*
-	 * Pass off the heavy lifting to spa_load().
-	 * Pass TRUE for mosconfig (unless this is a root pool) because
-	 * the user-supplied config is actually the one to trust when
+	 * Pass off the heavy lifting to spa_load().  Pass TRUE for mosconfig
+	 * because the user-supplied config is actually the one to trust when
 	 * doing an import.
 	 */
-	loaderr = error = spa_load(spa, config, SPA_LOAD_IMPORT, !isroot);
+	error = spa_load(spa, config, SPA_LOAD_IMPORT, B_TRUE);
 
 	spa_config_enter(spa, SCL_ALL, FTAG, RW_WRITER);
 	/*
-	 * Toss any existing sparelist, as it doesn't have any validity anymore,
-	 * and conflicts with spa_has_spare().
+	 * Toss any existing sparelist, as it doesn't have any validity
+	 * anymore, and conflicts with spa_has_spare().
 	 */
-	if (!isroot && spa->spa_spares.sav_config) {
+	if (spa->spa_spares.sav_config) {
 		nvlist_free(spa->spa_spares.sav_config);
 		spa->spa_spares.sav_config = NULL;
 		spa_load_spares(spa);
 	}
-	if (!isroot && spa->spa_l2cache.sav_config) {
+	if (spa->spa_l2cache.sav_config) {
 		nvlist_free(spa->spa_l2cache.sav_config);
 		spa->spa_l2cache.sav_config = NULL;
 		spa_load_l2cache(spa);
@@ -2228,7 +2564,8 @@ spa_import_common(const char *pool, nvlist_t *config, nvlist_t *props,
 	VERIFY(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE,
 	    &nvroot) == 0);
 	if (error == 0)
-		error = spa_validate_aux(spa, nvroot, -1ULL, VDEV_ALLOC_SPARE);
+		error = spa_validate_aux(spa, nvroot, -1ULL,
+		    VDEV_ALLOC_SPARE);
 	if (error == 0)
 		error = spa_validate_aux(spa, nvroot, -1ULL,
 		    VDEV_ALLOC_L2CACHE);
@@ -2239,29 +2576,15 @@ spa_import_common(const char *pool, nvlist_t *config, nvlist_t *props,
 
 	if (error != 0 || (props && spa_writeable(spa) &&
 	    (error = spa_prop_set(spa, props)))) {
-		if (loaderr != 0 && loaderr != EINVAL && allowfaulted) {
-			/*
-			 * If we failed to load the pool, but 'allowfaulted' is
-			 * set, then manually set the config as if the config
-			 * passed in was specified in the cache file.
-			 */
-			error = 0;
-			spa->spa_import_faulted = B_FALSE;
-			if (spa->spa_config == NULL)
-				spa->spa_config = spa_config_generate(spa,
-				    NULL, -1ULL, B_TRUE);
-			spa_unload(spa);
-			spa_deactivate(spa);
-			spa_config_sync(spa, B_FALSE, B_TRUE);
-		} else {
-			spa_unload(spa);
-			spa_deactivate(spa);
-			spa_remove(spa);
-		}
+		spa_unload(spa);
+		spa_deactivate(spa);
+		spa_remove(spa);
 		mutex_exit(&spa_namespace_lock);
 		return (error);
 	}
 
+	spa_async_resume(spa);
+
 	/*
 	 * Override any spares and level 2 cache devices as specified by
 	 * the user, as these may have correct device names/devids, etc.
@@ -2301,246 +2624,20 @@ spa_import_common(const char *pool, nvlist_t *config, nvlist_t *props,
 		/*
 		 * Update the config cache to include the newly-imported pool.
 		 */
-		spa_config_update_common(spa, SPA_CONFIG_UPDATE_POOL, isroot);
+		spa_config_update_common(spa, SPA_CONFIG_UPDATE_POOL, B_FALSE);
 	}
 
-	spa->spa_import_faulted = B_FALSE;
-	mutex_exit(&spa_namespace_lock);
-
-	return (0);
-}
-
-#ifdef _KERNEL
-/*
- * Build a "root" vdev for a top level vdev read in from a rootpool
- * device label.
- */
-static void
-spa_build_rootpool_config(nvlist_t *config)
-{
-	nvlist_t *nvtop, *nvroot;
-	uint64_t pgid;
-
-	/*
-	 * Add this top-level vdev to the child array.
-	 */
-	VERIFY(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, &nvtop)
-	    == 0);
-	VERIFY(nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_GUID, &pgid)
-	    == 0);
-
-	/*
-	 * Put this pool's top-level vdevs into a root vdev.
-	 */
-	VERIFY(nvlist_alloc(&nvroot, NV_UNIQUE_NAME, KM_SLEEP) == 0);
-	VERIFY(nvlist_add_string(nvroot, ZPOOL_CONFIG_TYPE, VDEV_TYPE_ROOT)
-	    == 0);
-	VERIFY(nvlist_add_uint64(nvroot, ZPOOL_CONFIG_ID, 0ULL) == 0);
-	VERIFY(nvlist_add_uint64(nvroot, ZPOOL_CONFIG_GUID, pgid) == 0);
-	VERIFY(nvlist_add_nvlist_array(nvroot, ZPOOL_CONFIG_CHILDREN,
-	    &nvtop, 1) == 0);
-
 	/*
-	 * Replace the existing vdev_tree with the new root vdev in
-	 * this pool's configuration (remove the old, add the new).
+	 * It's possible that the pool was expanded while it was exported.
+	 * We kick off an async task to handle this for us.
 	 */
-	VERIFY(nvlist_add_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, nvroot) == 0);
-	nvlist_free(nvroot);
-}
+	spa_async_request(spa, SPA_ASYNC_AUTOEXPAND);
 
-/*
- * Get the root pool information from the root disk, then import the root pool
- * during the system boot up time.
- */
-extern int vdev_disk_read_rootlabel(char *, char *, nvlist_t **);
-
-int
-spa_check_rootconf(char *devpath, char *devid, nvlist_t **bestconf,
-    uint64_t *besttxg)
-{
-	nvlist_t *config;
-	uint64_t txg;
-	int error;
-
-	if (error = vdev_disk_read_rootlabel(devpath, devid, &config))
-		return (error);
-
-	VERIFY(nvlist_lookup_uint64(config, ZPOOL_CONFIG_POOL_TXG, &txg) == 0);
-
-	if (bestconf != NULL)
-		*bestconf = config;
-	else
-		nvlist_free(config);
-	*besttxg = txg;
-	return (0);
-}
-
-boolean_t
-spa_rootdev_validate(nvlist_t *nv)
-{
-	uint64_t ival;
-
-	if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_OFFLINE, &ival) == 0 ||
-	    nvlist_lookup_uint64(nv, ZPOOL_CONFIG_FAULTED, &ival) == 0 ||
-	    nvlist_lookup_uint64(nv, ZPOOL_CONFIG_REMOVED, &ival) == 0)
-		return (B_FALSE);
-
-	return (B_TRUE);
-}
-
-
-/*
- * Given the boot device's physical path or devid, check if the device
- * is in a valid state.  If so, return the configuration from the vdev
- * label.
- */
-int
-spa_get_rootconf(char *devpath, char *devid, nvlist_t **bestconf)
-{
-	nvlist_t *conf = NULL;
-	uint64_t txg = 0;
-	nvlist_t *nvtop, **child;
-	char *type;
-	char *bootpath = NULL;
-	uint_t children, c;
-	char *tmp;
-	int error;
-
-	if (devpath && ((tmp = strchr(devpath, ' ')) != NULL))
-		*tmp = '\0';
-	if (error = spa_check_rootconf(devpath, devid, &conf, &txg)) {
-		cmn_err(CE_NOTE, "error reading device label");
-		return (error);
-	}
-	if (txg == 0) {
-		cmn_err(CE_NOTE, "this device is detached");
-		nvlist_free(conf);
-		return (EINVAL);
-	}
-
-	VERIFY(nvlist_lookup_nvlist(conf, ZPOOL_CONFIG_VDEV_TREE,
-	    &nvtop) == 0);
-	VERIFY(nvlist_lookup_string(nvtop, ZPOOL_CONFIG_TYPE, &type) == 0);
-
-	if (strcmp(type, VDEV_TYPE_DISK) == 0) {
-		if (spa_rootdev_validate(nvtop)) {
-			goto out;
-		} else {
-			nvlist_free(conf);
-			return (EINVAL);
-		}
-	}
-
-	ASSERT(strcmp(type, VDEV_TYPE_MIRROR) == 0);
-
-	VERIFY(nvlist_lookup_nvlist_array(nvtop, ZPOOL_CONFIG_CHILDREN,
-	    &child, &children) == 0);
-
-	/*
-	 * Go thru vdevs in the mirror to see if the given device
-	 * has the most recent txg. Only the device with the most
-	 * recent txg has valid information and should be booted.
-	 */
-	for (c = 0; c < children; c++) {
-		char *cdevid, *cpath;
-		uint64_t tmptxg;
-
-		cpath = NULL;
-		cdevid = NULL;
-		if (nvlist_lookup_string(child[c], ZPOOL_CONFIG_PHYS_PATH,
-		    &cpath) != 0 && nvlist_lookup_string(child[c],
-		    ZPOOL_CONFIG_DEVID, &cdevid) != 0)
-			return (EINVAL);
-		if ((spa_check_rootconf(cpath, cdevid, NULL,
-		    &tmptxg) == 0) && (tmptxg > txg)) {
-			txg = tmptxg;
-			VERIFY(nvlist_lookup_string(child[c],
-			    ZPOOL_CONFIG_PATH, &bootpath) == 0);
-		}
-	}
+	mutex_exit(&spa_namespace_lock);
 
-	/* Does the best device match the one we've booted from? */
-	if (bootpath) {
-		cmn_err(CE_NOTE, "try booting from '%s'", bootpath);
-		return (EINVAL);
-	}
-out:
-	*bestconf = conf;
 	return (0);
 }
 
-/*
- * Import a root pool.
- *
- * For x86. devpath_list will consist of devid and/or physpath name of
- * the vdev (e.g. "id1,sd@SSEAGATE..." or "/pci@1f,0/ide@d/disk@0,0:a").
- * The GRUB "findroot" command will return the vdev we should boot.
- *
- * For Sparc, devpath_list consists the physpath name of the booting device
- * no matter the rootpool is a single device pool or a mirrored pool.
- * e.g.
- *	"/pci@1f,0/ide@d/disk@0,0:a"
- */
-int
-spa_import_rootpool(char *devpath, char *devid)
-{
-	nvlist_t *conf = NULL;
-	char *pname;
-	int error;
-
-	/*
-	 * Get the vdev pathname and configuation from the most
-	 * recently updated vdev (highest txg).
-	 */
-	if (error = spa_get_rootconf(devpath, devid, &conf))
-		goto msg_out;
-
-	/*
-	 * Add type "root" vdev to the config.
-	 */
-	spa_build_rootpool_config(conf);
-
-	VERIFY(nvlist_lookup_string(conf, ZPOOL_CONFIG_POOL_NAME, &pname) == 0);
-
-	/*
-	 * We specify 'allowfaulted' for this to be treated like spa_open()
-	 * instead of spa_import().  This prevents us from marking vdevs as
-	 * persistently unavailable, and generates FMA ereports as if it were a
-	 * pool open, not import.
-	 */
-	error = spa_import_common(pname, conf, NULL, B_TRUE, B_TRUE);
-	ASSERT(error != EEXIST);
-
-	nvlist_free(conf);
-	return (error);
-
-msg_out:
-	cmn_err(CE_NOTE, "\n"
-	    "  ***************************************************  \n"
-	    "  *  This device is not bootable!                   *  \n"
-	    "  *  It is either offlined or detached or faulted.  *  \n"
-	    "  *  Please try to boot from a different device.    *  \n"
-	    "  ***************************************************  ");
-
-	return (error);
-}
-#endif
-
-/*
- * Import a non-root pool into the system.
- */
-int
-spa_import(const char *pool, nvlist_t *config, nvlist_t *props)
-{
-	return (spa_import_common(pool, config, props, B_FALSE, B_FALSE));
-}
-
-int
-spa_import_faulted(const char *pool, nvlist_t *config, nvlist_t *props)
-{
-	return (spa_import_common(pool, config, props, B_FALSE, B_TRUE));
-}
-
 
 /*
  * This (illegal) pool name is used when temporarily importing a spa_t in order
@@ -2624,8 +2721,10 @@ spa_tryimport(nvlist_t *tryconfig)
 		/*
 		 * Add the list of hot spares and level 2 cache devices.
 		 */
+		spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
 		spa_add_spares(spa, config);
 		spa_add_l2cache(spa, config);
+		spa_config_exit(spa, SCL_CONFIG, FTAG);
 	}
 
 	spa_unload(spa);
@@ -2971,10 +3070,9 @@ spa_vdev_attach(spa_t *spa, uint64_t guid, nvlist_t *nvroot, int replacing)
 	}
 
 	/*
-	 * Compare the new device size with the replaceable/attachable
-	 * device size.
+	 * Make sure the new device is big enough.
 	 */
-	if (newvd->vdev_psize < vdev_get_rsize(oldvd))
+	if (newvd->vdev_asize < vdev_get_min_asize(oldvd))
 		return (spa_vdev_exit(spa, newrootvd, txg, EOVERFLOW));
 
 	/*
@@ -3018,12 +3116,6 @@ spa_vdev_attach(spa_t *spa, uint64_t guid, nvlist_t *nvroot, int replacing)
 	newvd->vdev_id = pvd->vdev_children;
 	vdev_add_child(pvd, newvd);
 
-	/*
-	 * If newvd is smaller than oldvd, but larger than its rsize,
-	 * the addition of newvd may have decreased our parent's asize.
-	 */
-	pvd->vdev_asize = MIN(pvd->vdev_asize, newvd->vdev_asize);
-
 	tvd = newvd->vdev_top;
 	ASSERT(pvd->vdev_top == tvd);
 	ASSERT(tvd->vdev_parent == rvd);
@@ -3039,8 +3131,11 @@ spa_vdev_attach(spa_t *spa, uint64_t guid, nvlist_t *nvroot, int replacing)
 	vdev_dtl_dirty(newvd, DTL_MISSING,
 	    TXG_INITIAL, open_txg - TXG_INITIAL + 1);
 
-	if (newvd->vdev_isspare)
+	if (newvd->vdev_isspare) {
 		spa_spare_activate(newvd);
+		spa_event_notify(spa, newvd, ESC_ZFS_VDEV_SPARE);
+	}
+
 	oldvdpath = spa_strdup(oldvd->vdev_path);
 	newvdpath = spa_strdup(newvd->vdev_path);
 	newvd_isspare = newvd->vdev_isspare;
@@ -3237,12 +3332,16 @@ spa_vdev_detach(spa_t *spa, uint64_t guid, uint64_t pguid, int replace_done)
 	vdev_propagate_state(cvd);
 
 	/*
-	 * If the device we just detached was smaller than the others, it may be
-	 * possible to add metaslabs (i.e. grow the pool).  vdev_metaslab_init()
-	 * can't fail because the existing metaslabs are already in core, so
-	 * there's nothing to read from disk.
+	 * If the 'autoexpand' property is set on the pool then automatically
+	 * try to expand the size of the pool. For example if the device we
+	 * just detached was smaller than the others, it may be possible to
+	 * add metaslabs (i.e. grow the pool). We need to reopen the vdev
+	 * first so that we can obtain the updated sizes of the leaf vdevs.
 	 */
-	VERIFY(vdev_metaslab_init(tvd, txg) == 0);
+	if (spa->spa_autoexpand) {
+		vdev_reopen(tvd);
+		vdev_expand(tvd, txg);
+	}
 
 	vdev_config_dirty(tvd);
 
@@ -3400,9 +3499,8 @@ static vdev_t *
 spa_vdev_resilver_done_hunt(vdev_t *vd)
 {
 	vdev_t *newvd, *oldvd;
-	int c;
 
-	for (c = 0; c < vd->vdev_children; c++) {
+	for (int c = 0; c < vd->vdev_children; c++) {
 		oldvd = spa_vdev_resilver_done_hunt(vd->vdev_child[c]);
 		if (oldvd != NULL)
 			return (oldvd);
@@ -3475,59 +3573,50 @@ spa_vdev_resilver_done(spa_t *spa)
 }
 
 /*
- * Update the stored path for this vdev.  Dirty the vdev configuration, relying
- * on spa_vdev_enter/exit() to synchronize the labels and cache.
+ * Update the stored path or FRU for this vdev.  Dirty the vdev configuration,
+ * relying on spa_vdev_enter/exit() to synchronize the labels and cache.
  */
 int
-spa_vdev_setpath(spa_t *spa, uint64_t guid, const char *newpath)
+spa_vdev_set_common(spa_t *spa, uint64_t guid, const char *value,
+    boolean_t ispath)
 {
 	vdev_t *vd;
 	uint64_t txg;
 
 	txg = spa_vdev_enter(spa);
 
-	if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL) {
-		/*
-		 * Determine if this is a reference to a hot spare device.  If
-		 * it is, update the path manually as there is no associated
-		 * vdev_t that can be synced to disk.
-		 */
-		nvlist_t **spares;
-		uint_t i, nspares;
-
-		if (spa->spa_spares.sav_config != NULL) {
-			VERIFY(nvlist_lookup_nvlist_array(
-			    spa->spa_spares.sav_config, ZPOOL_CONFIG_SPARES,
-			    &spares, &nspares) == 0);
-			for (i = 0; i < nspares; i++) {
-				uint64_t theguid;
-				VERIFY(nvlist_lookup_uint64(spares[i],
-				    ZPOOL_CONFIG_GUID, &theguid) == 0);
-				if (theguid == guid) {
-					VERIFY(nvlist_add_string(spares[i],
-					    ZPOOL_CONFIG_PATH, newpath) == 0);
-					spa_load_spares(spa);
-					spa->spa_spares.sav_sync = B_TRUE;
-					return (spa_vdev_exit(spa, NULL, txg,
-					    0));
-				}
-			}
-		}
-
+	if ((vd = spa_lookup_by_guid(spa, guid, B_TRUE)) == NULL)
 		return (spa_vdev_exit(spa, NULL, txg, ENOENT));
-	}
 
 	if (!vd->vdev_ops->vdev_op_leaf)
 		return (spa_vdev_exit(spa, NULL, txg, ENOTSUP));
 
-	spa_strfree(vd->vdev_path);
-	vd->vdev_path = spa_strdup(newpath);
+	if (ispath) {
+		spa_strfree(vd->vdev_path);
+		vd->vdev_path = spa_strdup(value);
+	} else {
+		if (vd->vdev_fru != NULL)
+			spa_strfree(vd->vdev_fru);
+		vd->vdev_fru = spa_strdup(value);
+	}
 
 	vdev_config_dirty(vd->vdev_top);
 
 	return (spa_vdev_exit(spa, NULL, txg, 0));
 }
 
+int
+spa_vdev_setpath(spa_t *spa, uint64_t guid, const char *newpath)
+{
+	return (spa_vdev_set_common(spa, guid, newpath, B_TRUE));
+}
+
+int
+spa_vdev_setfru(spa_t *spa, uint64_t guid, const char *newfru)
+{
+	return (spa_vdev_set_common(spa, guid, newfru, B_FALSE));
+}
+
 /*
  * ==========================================================================
  * SPA Scrubbing
@@ -3599,6 +3688,37 @@ spa_async_probe(spa_t *spa, vdev_t *vd)
 }
 
 static void
+spa_async_autoexpand(spa_t *spa, vdev_t *vd)
+{
+	sysevent_id_t eid;
+	nvlist_t *attr;
+	char *physpath;
+
+	if (!spa->spa_autoexpand)
+		return;
+
+	for (int c = 0; c < vd->vdev_children; c++) {
+		vdev_t *cvd = vd->vdev_child[c];
+		spa_async_autoexpand(spa, cvd);
+	}
+
+	if (!vd->vdev_ops->vdev_op_leaf || vd->vdev_physpath == NULL)
+		return;
+
+	physpath = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
+	(void) snprintf(physpath, MAXPATHLEN, "/devices%s", vd->vdev_physpath);
+
+	VERIFY(nvlist_alloc(&attr, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+	VERIFY(nvlist_add_string(attr, DEV_PHYS_PATH, physpath) == 0);
+
+	(void) ddi_log_sysevent(zfs_dip, SUNW_VENDOR, EC_DEV_STATUS,
+	    ESC_DEV_DLE, attr, &eid, DDI_SLEEP);
+
+	nvlist_free(attr);
+	kmem_free(physpath, MAXPATHLEN);
+}
+
+static void
 spa_async_thread(spa_t *spa)
 {
 	int tasks;
@@ -3614,9 +3734,33 @@ spa_async_thread(spa_t *spa)
 	 * See if the config needs to be updated.
 	 */
 	if (tasks & SPA_ASYNC_CONFIG_UPDATE) {
+		uint64_t oldsz, space_update;
+
 		mutex_enter(&spa_namespace_lock);
+		oldsz = spa_get_space(spa);
 		spa_config_update(spa, SPA_CONFIG_UPDATE_POOL);
+		space_update = spa_get_space(spa) - oldsz;
 		mutex_exit(&spa_namespace_lock);
+
+		/*
+		 * If the pool grew as a result of the config update,
+		 * then log an internal history event.
+		 */
+		if (space_update) {
+			dmu_tx_t *tx;
+
+			tx = dmu_tx_create_dd(spa_get_dsl(spa)->dp_mos_dir);
+			if (dmu_tx_assign(tx, TXG_WAIT) == 0) {
+				spa_history_internal_log(LOG_POOL_VDEV_ONLINE,
+				    spa, tx, CRED(),
+				    "pool '%s' size: %llu(+%llu)",
+				    spa_name(spa), spa_get_space(spa),
+				    space_update);
+				dmu_tx_commit(tx);
+			} else {
+				dmu_tx_abort(tx);
+			}
+		}
 	}
 
 	/*
@@ -3632,6 +3776,12 @@ spa_async_thread(spa_t *spa)
 		(void) spa_vdev_state_exit(spa, NULL, 0);
 	}
 
+	if ((tasks & SPA_ASYNC_AUTOEXPAND) && !spa_suspended(spa)) {
+		spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER);
+		spa_async_autoexpand(spa, spa->spa_root_vdev);
+		spa_config_exit(spa, SCL_CONFIG, FTAG);
+	}
+
 	/*
 	 * See if any devices need to be probed.
 	 */
@@ -3944,6 +4094,10 @@ spa_sync_props(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
 			case ZPOOL_PROP_FAILUREMODE:
 				spa->spa_failmode = intval;
 				break;
+			case ZPOOL_PROP_AUTOEXPAND:
+				spa->spa_autoexpand = intval;
+				spa_async_request(spa, SPA_ASYNC_AUTOEXPAND);
+				break;
 			default:
 				break;
 			}
@@ -4105,9 +4259,8 @@ spa_sync(spa_t *spa, uint64_t txg)
 			int svdcount = 0;
 			int children = rvd->vdev_children;
 			int c0 = spa_get_random(children);
-			int c;
 
-			for (c = 0; c < children; c++) {
+			for (int c = 0; c < children; c++) {
 				vd = rvd->vdev_child[(c0 + c) % children];
 				if (vd->vdev_ms_array == 0 || vd->vdev_islog)
 					continue;
@@ -4115,10 +4268,16 @@ spa_sync(spa_t *spa, uint64_t txg)
 				if (svdcount == SPA_DVAS_PER_BP)
 					break;
 			}
-			error = vdev_config_sync(svd, svdcount, txg);
+			error = vdev_config_sync(svd, svdcount, txg, B_FALSE);
+			if (error != 0)
+				error = vdev_config_sync(svd, svdcount, txg,
+				    B_TRUE);
 		} else {
 			error = vdev_config_sync(rvd->vdev_child,
-			    rvd->vdev_children, txg);
+			    rvd->vdev_children, txg, B_FALSE);
+			if (error != 0)
+				error = vdev_config_sync(rvd->vdev_child,
+				    rvd->vdev_children, txg, B_TRUE);
 		}
 
 		spa_config_exit(spa, SCL_STATE, FTAG);
@@ -4239,7 +4398,7 @@ spa_evict_all(void)
 }
 
 vdev_t *
-spa_lookup_by_guid(spa_t *spa, uint64_t guid, boolean_t l2cache)
+spa_lookup_by_guid(spa_t *spa, uint64_t guid, boolean_t aux)
 {
 	vdev_t *vd;
 	int i;
@@ -4247,12 +4406,18 @@ spa_lookup_by_guid(spa_t *spa, uint64_t guid, boolean_t l2cache)
 	if ((vd = vdev_lookup_by_guid(spa->spa_root_vdev, guid)) != NULL)
 		return (vd);
 
-	if (l2cache) {
+	if (aux) {
 		for (i = 0; i < spa->spa_l2cache.sav_count; i++) {
 			vd = spa->spa_l2cache.sav_vdevs[i];
 			if (vd->vdev_guid == guid)
 				return (vd);
 		}
+
+		for (i = 0; i < spa->spa_spares.sav_count; i++) {
+			vd = spa->spa_spares.sav_vdevs[i];
+			if (vd->vdev_guid == guid)
+				return (vd);
+		}
 	}
 
 	return (NULL);
diff --git a/module/zfs/spa_config.c b/module/zfs/spa_config.c
index 1c47efd0c..7103e179b 100644
--- a/module/zfs/spa_config.c
+++ b/module/zfs/spa_config.c
@@ -432,10 +432,9 @@ spa_config_update_common(spa_t *spa, int what, boolean_t isroot)
 		 */
 		for (c = 0; c < rvd->vdev_children; c++) {
 			vdev_t *tvd = rvd->vdev_child[c];
-			if (tvd->vdev_ms_array == 0) {
-				vdev_init(tvd, txg);
-				vdev_config_dirty(tvd);
-			}
+			if (tvd->vdev_ms_array == 0)
+				vdev_metaslab_set_size(tvd);
+			vdev_expand(tvd, txg);
 		}
 	}
 	spa_config_exit(spa, SCL_ALL, FTAG);
diff --git a/module/zfs/spa_errlog.c b/module/zfs/spa_errlog.c
index c642bd768..ac0a20aaf 100644
--- a/module/zfs/spa_errlog.c
+++ b/module/zfs/spa_errlog.c
@@ -19,12 +19,10 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 /*
  * Routines to manage the on-disk persistent error log.
  *
@@ -61,8 +59,8 @@
  * lowercase hexidecimal numbers that don't overflow.
  */
 #ifdef _KERNEL
-static uint64_t
-strtonum(char *str, char **nptr)
+uint64_t
+strtonum(const char *str, char **nptr)
 {
 	uint64_t val = 0;
 	char c;
@@ -82,7 +80,8 @@ strtonum(char *str, char **nptr)
 		str++;
 	}
 
-	*nptr = str;
+	if (nptr)
+		*nptr = (char *)str;
 
 	return (val);
 }
diff --git a/module/zfs/spa_history.c b/module/zfs/spa_history.c
index c997240c1..97d97d847 100644
--- a/module/zfs/spa_history.c
+++ b/module/zfs/spa_history.c
@@ -20,12 +20,10 @@
  */
 
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/spa.h>
 #include <sys/spa_impl.h>
 #include <sys/zap.h>
@@ -127,12 +125,12 @@ spa_history_advance_bof(spa_t *spa, spa_history_phys_t *shpp)
 	firstread = MIN(sizeof (reclen), shpp->sh_phys_max_off - phys_bof);
 
 	if ((err = dmu_read(mos, spa->spa_history, phys_bof, firstread,
-	    buf)) != 0)
+	    buf, DMU_READ_PREFETCH)) != 0)
 		return (err);
 	if (firstread != sizeof (reclen)) {
 		if ((err = dmu_read(mos, spa->spa_history,
 		    shpp->sh_pool_create_len, sizeof (reclen) - firstread,
-		    buf + firstread)) != 0)
+		    buf + firstread, DMU_READ_PREFETCH)) != 0)
 			return (err);
 	}
 
@@ -380,10 +378,11 @@ spa_history_get(spa_t *spa, uint64_t *offp, uint64_t *len, char *buf)
 		return (0);
 	}
 
-	err = dmu_read(mos, spa->spa_history, phys_read_off, read_len, buf);
+	err = dmu_read(mos, spa->spa_history, phys_read_off, read_len, buf,
+	    DMU_READ_PREFETCH);
 	if (leftover && err == 0) {
 		err = dmu_read(mos, spa->spa_history, shpp->sh_pool_create_len,
-		    leftover, buf + read_len);
+		    leftover, buf + read_len, DMU_READ_PREFETCH);
 	}
 	mutex_exit(&spa->spa_history_lock);
 
diff --git a/module/zfs/spa_misc.c b/module/zfs/spa_misc.c
index 485e83fce..aea3f5625 100644
--- a/module/zfs/spa_misc.c
+++ b/module/zfs/spa_misc.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -425,7 +425,6 @@ spa_add(const char *name, const char *altroot)
 	spa = kmem_zalloc(sizeof (spa_t), KM_SLEEP);
 
 	mutex_init(&spa->spa_async_lock, NULL, MUTEX_DEFAULT, NULL);
-	mutex_init(&spa->spa_async_root_lock, NULL, MUTEX_DEFAULT, NULL);
 	mutex_init(&spa->spa_scrub_lock, NULL, MUTEX_DEFAULT, NULL);
 	mutex_init(&spa->spa_errlog_lock, NULL, MUTEX_DEFAULT, NULL);
 	mutex_init(&spa->spa_errlist_lock, NULL, MUTEX_DEFAULT, NULL);
@@ -434,7 +433,6 @@ spa_add(const char *name, const char *altroot)
 	mutex_init(&spa->spa_props_lock, NULL, MUTEX_DEFAULT, NULL);
 
 	cv_init(&spa->spa_async_cv, NULL, CV_DEFAULT, NULL);
-	cv_init(&spa->spa_async_root_cv, NULL, CV_DEFAULT, NULL);
 	cv_init(&spa->spa_scrub_io_cv, NULL, CV_DEFAULT, NULL);
 	cv_init(&spa->spa_suspend_cv, NULL, CV_DEFAULT, NULL);
 
@@ -508,12 +506,10 @@ spa_remove(spa_t *spa)
 	spa_config_lock_destroy(spa);
 
 	cv_destroy(&spa->spa_async_cv);
-	cv_destroy(&spa->spa_async_root_cv);
 	cv_destroy(&spa->spa_scrub_io_cv);
 	cv_destroy(&spa->spa_suspend_cv);
 
 	mutex_destroy(&spa->spa_async_lock);
-	mutex_destroy(&spa->spa_async_root_lock);
 	mutex_destroy(&spa->spa_scrub_lock);
 	mutex_destroy(&spa->spa_errlog_lock);
 	mutex_destroy(&spa->spa_errlist_lock);
diff --git a/module/zfs/space_map.c b/module/zfs/space_map.c
index 1cdacc81d..75b55d5c1 100644
--- a/module/zfs/space_map.c
+++ b/module/zfs/space_map.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -116,12 +116,23 @@ space_map_add(space_map_t *sm, uint64_t start, uint64_t size)
 
 	if (merge_before && merge_after) {
 		avl_remove(&sm->sm_root, ss_before);
+		if (sm->sm_pp_root) {
+			avl_remove(sm->sm_pp_root, ss_before);
+			avl_remove(sm->sm_pp_root, ss_after);
+		}
 		ss_after->ss_start = ss_before->ss_start;
 		kmem_free(ss_before, sizeof (*ss_before));
+		ss = ss_after;
 	} else if (merge_before) {
 		ss_before->ss_end = end;
+		if (sm->sm_pp_root)
+			avl_remove(sm->sm_pp_root, ss_before);
+		ss = ss_before;
 	} else if (merge_after) {
 		ss_after->ss_start = start;
+		if (sm->sm_pp_root)
+			avl_remove(sm->sm_pp_root, ss_after);
+		ss = ss_after;
 	} else {
 		ss = kmem_alloc(sizeof (*ss), KM_SLEEP);
 		ss->ss_start = start;
@@ -129,6 +140,9 @@ space_map_add(space_map_t *sm, uint64_t start, uint64_t size)
 		avl_insert(&sm->sm_root, ss, where);
 	}
 
+	if (sm->sm_pp_root)
+		avl_add(sm->sm_pp_root, ss);
+
 	sm->sm_space += size;
 }
 
@@ -163,12 +177,17 @@ space_map_remove(space_map_t *sm, uint64_t start, uint64_t size)
 	left_over = (ss->ss_start != start);
 	right_over = (ss->ss_end != end);
 
+	if (sm->sm_pp_root)
+		avl_remove(sm->sm_pp_root, ss);
+
 	if (left_over && right_over) {
 		newseg = kmem_alloc(sizeof (*newseg), KM_SLEEP);
 		newseg->ss_start = end;
 		newseg->ss_end = ss->ss_end;
 		ss->ss_end = start;
 		avl_insert_here(&sm->sm_root, newseg, ss, AVL_AFTER);
+		if (sm->sm_pp_root)
+			avl_add(sm->sm_pp_root, newseg);
 	} else if (left_over) {
 		ss->ss_end = start;
 	} else if (right_over) {
@@ -176,8 +195,12 @@ space_map_remove(space_map_t *sm, uint64_t start, uint64_t size)
 	} else {
 		avl_remove(&sm->sm_root, ss);
 		kmem_free(ss, sizeof (*ss));
+		ss = NULL;
 	}
 
+	if (sm->sm_pp_root && ss != NULL)
+		avl_add(sm->sm_pp_root, ss);
+
 	sm->sm_space -= size;
 }
 
@@ -288,7 +311,8 @@ space_map_load(space_map_t *sm, space_map_ops_t *ops, uint8_t maptype,
 		    smo->smo_object, offset, size);
 
 		mutex_exit(sm->sm_lock);
-		error = dmu_read(os, smo->smo_object, offset, size, entry_map);
+		error = dmu_read(os, smo->smo_object, offset, size, entry_map,
+		    DMU_READ_PREFETCH);
 		mutex_enter(sm->sm_lock);
 		if (error != 0)
 			break;
@@ -342,6 +366,15 @@ space_map_unload(space_map_t *sm)
 }
 
 uint64_t
+space_map_maxsize(space_map_t *sm)
+{
+	if (sm->sm_loaded && sm->sm_ops != NULL)
+		return (sm->sm_ops->smop_max(sm));
+	else
+		return (-1ULL);
+}
+
+uint64_t
 space_map_alloc(space_map_t *sm, uint64_t size)
 {
 	uint64_t start;
diff --git a/module/zfs/vdev.c b/module/zfs/vdev.c
index 2554f96a9..3fa677e05 100644
--- a/module/zfs/vdev.c
+++ b/module/zfs/vdev.c
@@ -39,6 +39,7 @@
 #include <sys/zap.h>
 #include <sys/fs/zfs.h>
 #include <sys/arc.h>
+#include <sys/zil.h>
 
 /*
  * Virtual device management.
@@ -83,9 +84,8 @@ vdev_default_asize(vdev_t *vd, uint64_t psize)
 {
 	uint64_t asize = P2ROUNDUP(psize, 1ULL << vd->vdev_top->vdev_ashift);
 	uint64_t csize;
-	uint64_t c;
 
-	for (c = 0; c < vd->vdev_children; c++) {
+	for (int c = 0; c < vd->vdev_children; c++) {
 		csize = vdev_psize_to_asize(vd->vdev_child[c], psize);
 		asize = MAX(asize, csize);
 	}
@@ -94,40 +94,47 @@ vdev_default_asize(vdev_t *vd, uint64_t psize)
 }
 
 /*
- * Get the replaceable or attachable device size.
- * If the parent is a mirror or raidz, the replaceable size is the minimum
- * psize of all its children. For the rest, just return our own psize.
- *
- * e.g.
- *			psize	rsize
- * root			-	-
- *	mirror/raidz	-	-
- *	    disk1	20g	20g
- *	    disk2 	40g	20g
- *	disk3 		80g	80g
+ * Get the minimum allocatable size. We define the allocatable size as
+ * the vdev's asize rounded to the nearest metaslab. This allows us to
+ * replace or attach devices which don't have the same physical size but
+ * can still satisfy the same number of allocations.
  */
 uint64_t
-vdev_get_rsize(vdev_t *vd)
+vdev_get_min_asize(vdev_t *vd)
 {
-	vdev_t *pvd, *cvd;
-	uint64_t c, rsize;
+	vdev_t *pvd = vd->vdev_parent;
 
-	pvd = vd->vdev_parent;
+	/*
+	 * The our parent is NULL (inactive spare or cache) or is the root,
+	 * just return our own asize.
+	 */
+	if (pvd == NULL)
+		return (vd->vdev_asize);
 
 	/*
-	 * If our parent is NULL or the root, just return our own psize.
+	 * The top-level vdev just returns the allocatable size rounded
+	 * to the nearest metaslab.
 	 */
-	if (pvd == NULL || pvd->vdev_parent == NULL)
-		return (vd->vdev_psize);
+	if (vd == vd->vdev_top)
+		return (P2ALIGN(vd->vdev_asize, 1ULL << vd->vdev_ms_shift));
 
-	rsize = 0;
+	/*
+	 * The allocatable space for a raidz vdev is N * sizeof(smallest child),
+	 * so each child must provide at least 1/Nth of its asize.
+	 */
+	if (pvd->vdev_ops == &vdev_raidz_ops)
+		return (pvd->vdev_min_asize / pvd->vdev_children);
 
-	for (c = 0; c < pvd->vdev_children; c++) {
-		cvd = pvd->vdev_child[c];
-		rsize = MIN(rsize - 1, cvd->vdev_psize - 1) + 1;
-	}
+	return (pvd->vdev_min_asize);
+}
+
+void
+vdev_set_min_asize(vdev_t *vd)
+{
+	vd->vdev_min_asize = vdev_get_min_asize(vd);
 
-	return (rsize);
+	for (int c = 0; c < vd->vdev_children; c++)
+		vdev_set_min_asize(vd->vdev_child[c]);
 }
 
 vdev_t *
@@ -148,13 +155,12 @@ vdev_lookup_top(spa_t *spa, uint64_t vdev)
 vdev_t *
 vdev_lookup_by_guid(vdev_t *vd, uint64_t guid)
 {
-	int c;
 	vdev_t *mvd;
 
 	if (vd->vdev_guid == guid)
 		return (vd);
 
-	for (c = 0; c < vd->vdev_children; c++)
+	for (int c = 0; c < vd->vdev_children; c++)
 		if ((mvd = vdev_lookup_by_guid(vd->vdev_child[c], guid)) !=
 		    NULL)
 			return (mvd);
@@ -250,17 +256,17 @@ vdev_compact_children(vdev_t *pvd)
 {
 	vdev_t **newchild, *cvd;
 	int oldc = pvd->vdev_children;
-	int newc, c;
+	int newc;
 
 	ASSERT(spa_config_held(pvd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 
-	for (c = newc = 0; c < oldc; c++)
+	for (int c = newc = 0; c < oldc; c++)
 		if (pvd->vdev_child[c])
 			newc++;
 
 	newchild = kmem_alloc(newc * sizeof (vdev_t *), KM_SLEEP);
 
-	for (c = newc = 0; c < oldc; c++) {
+	for (int c = newc = 0; c < oldc; c++) {
 		if ((cvd = pvd->vdev_child[c]) != NULL) {
 			newchild[newc] = cvd;
 			cvd->vdev_id = newc++;
@@ -372,6 +378,9 @@ vdev_alloc(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent, uint_t id,
 	} else if (alloctype == VDEV_ALLOC_L2CACHE) {
 		if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
 			return (EINVAL);
+	} else if (alloctype == VDEV_ALLOC_ROOTPOOL) {
+		if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_GUID, &guid) != 0)
+			return (EINVAL);
 	}
 
 	/*
@@ -435,6 +444,8 @@ vdev_alloc(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent, uint_t id,
 	if (nvlist_lookup_string(nv, ZPOOL_CONFIG_PHYS_PATH,
 	    &vd->vdev_physpath) == 0)
 		vd->vdev_physpath = spa_strdup(vd->vdev_physpath);
+	if (nvlist_lookup_string(nv, ZPOOL_CONFIG_FRU, &vd->vdev_fru) == 0)
+		vd->vdev_fru = spa_strdup(vd->vdev_fru);
 
 	/*
 	 * Set the whole_disk property.  If it's not specified, leave the value
@@ -448,9 +459,8 @@ vdev_alloc(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent, uint_t id,
 	 * Look for the 'not present' flag.  This will only be set if the device
 	 * was not present at the time of import.
 	 */
-	if (!spa->spa_import_faulted)
-		(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_NOT_PRESENT,
-		    &vd->vdev_not_present);
+	(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_NOT_PRESENT,
+	    &vd->vdev_not_present);
 
 	/*
 	 * Get the alignment requirement.
@@ -473,13 +483,23 @@ vdev_alloc(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent, uint_t id,
 	 * If we're a leaf vdev, try to load the DTL object and other state.
 	 */
 	if (vd->vdev_ops->vdev_op_leaf &&
-	    (alloctype == VDEV_ALLOC_LOAD || alloctype == VDEV_ALLOC_L2CACHE)) {
+	    (alloctype == VDEV_ALLOC_LOAD || alloctype == VDEV_ALLOC_L2CACHE ||
+	    alloctype == VDEV_ALLOC_ROOTPOOL)) {
 		if (alloctype == VDEV_ALLOC_LOAD) {
 			(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_DTL,
 			    &vd->vdev_dtl_smo.smo_object);
 			(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_UNSPARE,
 			    &vd->vdev_unspare);
 		}
+
+		if (alloctype == VDEV_ALLOC_ROOTPOOL) {
+			uint64_t spare = 0;
+
+			if (nvlist_lookup_uint64(nv, ZPOOL_CONFIG_IS_SPARE,
+			    &spare) == 0 && spare)
+				spa_spare_add(vd);
+		}
+
 		(void) nvlist_lookup_uint64(nv, ZPOOL_CONFIG_OFFLINE,
 		    &vd->vdev_offline);
 
@@ -511,7 +531,6 @@ vdev_alloc(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent, uint_t id,
 void
 vdev_free(vdev_t *vd)
 {
-	int c;
 	spa_t *spa = vd->vdev_spa;
 
 	/*
@@ -525,7 +544,7 @@ vdev_free(vdev_t *vd)
 	/*
 	 * Free all children.
 	 */
-	for (c = 0; c < vd->vdev_children; c++)
+	for (int c = 0; c < vd->vdev_children; c++)
 		vdev_free(vd->vdev_child[c]);
 
 	ASSERT(vd->vdev_child == NULL);
@@ -560,6 +579,8 @@ vdev_free(vdev_t *vd)
 		spa_strfree(vd->vdev_devid);
 	if (vd->vdev_physpath)
 		spa_strfree(vd->vdev_physpath);
+	if (vd->vdev_fru)
+		spa_strfree(vd->vdev_fru);
 
 	if (vd->vdev_isspare)
 		spa_spare_remove(vd);
@@ -653,14 +674,12 @@ vdev_top_transfer(vdev_t *svd, vdev_t *tvd)
 static void
 vdev_top_update(vdev_t *tvd, vdev_t *vd)
 {
-	int c;
-
 	if (vd == NULL)
 		return;
 
 	vd->vdev_top = tvd;
 
-	for (c = 0; c < vd->vdev_children; c++)
+	for (int c = 0; c < vd->vdev_children; c++)
 		vdev_top_update(tvd, vd->vdev_child[c]);
 }
 
@@ -679,6 +698,7 @@ vdev_add_parent(vdev_t *cvd, vdev_ops_t *ops)
 	mvd = vdev_alloc_common(spa, cvd->vdev_id, 0, ops);
 
 	mvd->vdev_asize = cvd->vdev_asize;
+	mvd->vdev_min_asize = cvd->vdev_min_asize;
 	mvd->vdev_ashift = cvd->vdev_ashift;
 	mvd->vdev_state = cvd->vdev_state;
 
@@ -751,6 +771,15 @@ vdev_metaslab_init(vdev_t *vd, uint64_t txg)
 	if (vd->vdev_ms_shift == 0)	/* not being allocated from yet */
 		return (0);
 
+	/*
+	 * Compute the raidz-deflation ratio.  Note, we hard-code
+	 * in 128k (1 << 17) because it is the current "typical" blocksize.
+	 * Even if SPA_MAXBLOCKSIZE changes, this algorithm must never change,
+	 * or we will inconsistently account for existing bp's.
+	 */
+	vd->vdev_deflate_ratio = (1 << 17) /
+	    (vdev_psize_to_asize(vd, 1 << 17) >> SPA_MINBLOCKSHIFT);
+
 	ASSERT(oldc <= newc);
 
 	if (vd->vdev_islog)
@@ -776,7 +805,8 @@ vdev_metaslab_init(vdev_t *vd, uint64_t txg)
 		if (txg == 0) {
 			uint64_t object = 0;
 			error = dmu_read(mos, vd->vdev_ms_array,
-			    m * sizeof (uint64_t), sizeof (uint64_t), &object);
+			    m * sizeof (uint64_t), sizeof (uint64_t), &object,
+			    DMU_READ_PREFETCH);
 			if (error)
 				return (error);
 			if (object != 0) {
@@ -903,7 +933,7 @@ vdev_probe(vdev_t *vd, zio_t *zio)
 
 		vps->vps_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_PROBE |
 		    ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_AGGREGATE |
-		    ZIO_FLAG_DONT_RETRY;
+		    ZIO_FLAG_TRYHARD;
 
 		if (spa_config_held(spa, SCL_ZIO, RW_WRITER)) {
 			/*
@@ -950,8 +980,8 @@ vdev_probe(vdev_t *vd, zio_t *zio)
 	for (int l = 1; l < VDEV_LABELS; l++) {
 		zio_nowait(zio_read_phys(pio, vd,
 		    vdev_label_offset(vd->vdev_psize, l,
-		    offsetof(vdev_label_t, vl_pad)),
-		    VDEV_SKIP_SIZE, zio_buf_alloc(VDEV_SKIP_SIZE),
+		    offsetof(vdev_label_t, vl_pad2)),
+		    VDEV_PAD_SIZE, zio_buf_alloc(VDEV_PAD_SIZE),
 		    ZIO_CHECKSUM_OFF, vdev_probe_done, vps,
 		    ZIO_PRIORITY_SYNC_READ, vps->vps_flags, B_TRUE));
 	}
@@ -971,7 +1001,6 @@ vdev_open(vdev_t *vd)
 {
 	spa_t *spa = vd->vdev_spa;
 	int error;
-	int c;
 	uint64_t osize = 0;
 	uint64_t asize, psize;
 	uint64_t ashift = 0;
@@ -983,6 +1012,9 @@ vdev_open(vdev_t *vd)
 	    vd->vdev_state == VDEV_STATE_OFFLINE);
 
 	vd->vdev_stat.vs_aux = VDEV_AUX_NONE;
+	vd->vdev_cant_read = B_FALSE;
+	vd->vdev_cant_write = B_FALSE;
+	vd->vdev_min_asize = vdev_get_min_asize(vd);
 
 	if (!vd->vdev_removed && vd->vdev_faulted) {
 		ASSERT(vd->vdev_children == 0);
@@ -998,7 +1030,7 @@ vdev_open(vdev_t *vd)
 	error = vd->vdev_ops->vdev_op_open(vd, &osize, &ashift);
 
 	if (zio_injection_enabled && error == 0)
-		error = zio_handle_device_injection(vd, ENXIO);
+		error = zio_handle_device_injection(vd, NULL, ENXIO);
 
 	if (error) {
 		if (vd->vdev_removed &&
@@ -1020,12 +1052,13 @@ vdev_open(vdev_t *vd)
 		vd->vdev_state = VDEV_STATE_HEALTHY;
 	}
 
-	for (c = 0; c < vd->vdev_children; c++)
+	for (int c = 0; c < vd->vdev_children; c++) {
 		if (vd->vdev_child[c]->vdev_state != VDEV_STATE_HEALTHY) {
 			vdev_set_state(vd, B_TRUE, VDEV_STATE_DEGRADED,
 			    VDEV_AUX_NONE);
 			break;
 		}
+	}
 
 	osize = P2ALIGN(osize, (uint64_t)sizeof (vdev_label_t));
 
@@ -1050,6 +1083,15 @@ vdev_open(vdev_t *vd)
 
 	vd->vdev_psize = psize;
 
+	/*
+	 * Make sure the allocatable size hasn't shrunk.
+	 */
+	if (asize < vd->vdev_min_asize) {
+		vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
+		    VDEV_AUX_BAD_LABEL);
+		return (EINVAL);
+	}
+
 	if (vd->vdev_asize == 0) {
 		/*
 		 * This is the first-ever open, so use the computed values.
@@ -1066,25 +1108,18 @@ vdev_open(vdev_t *vd)
 			    VDEV_AUX_BAD_LABEL);
 			return (EINVAL);
 		}
+	}
 
-		/*
-		 * Make sure the device hasn't shrunk.
-		 */
-		if (asize < vd->vdev_asize) {
-			vdev_set_state(vd, B_TRUE, VDEV_STATE_CANT_OPEN,
-			    VDEV_AUX_BAD_LABEL);
-			return (EINVAL);
-		}
+	/*
+	 * If all children are healthy and the asize has increased,
+	 * then we've experienced dynamic LUN growth.  If automatic
+	 * expansion is enabled then use the additional space.
+	 */
+	if (vd->vdev_state == VDEV_STATE_HEALTHY && asize > vd->vdev_asize &&
+	    (vd->vdev_expanding || spa->spa_autoexpand))
+		vd->vdev_asize = asize;
 
-		/*
-		 * If all children are healthy and the asize has increased,
-		 * then we've experienced dynamic LUN growth.
-		 */
-		if (vd->vdev_state == VDEV_STATE_HEALTHY &&
-		    asize > vd->vdev_asize) {
-			vd->vdev_asize = asize;
-		}
-	}
+	vdev_set_min_asize(vd);
 
 	/*
 	 * Ensure we can issue some IO before declaring the
@@ -1098,18 +1133,6 @@ vdev_open(vdev_t *vd)
 	}
 
 	/*
-	 * If this is a top-level vdev, compute the raidz-deflation
-	 * ratio.  Note, we hard-code in 128k (1<<17) because it is the
-	 * current "typical" blocksize.  Even if SPA_MAXBLOCKSIZE
-	 * changes, this algorithm must never change, or we will
-	 * inconsistently account for existing bp's.
-	 */
-	if (vd->vdev_top == vd) {
-		vd->vdev_deflate_ratio = (1<<17) /
-		    (vdev_psize_to_asize(vd, 1<<17) >> SPA_MINBLOCKSHIFT);
-	}
-
-	/*
 	 * If a leaf vdev has a DTL, and seems healthy, then kick off a
 	 * resilver.  But don't do this if we are doing a reopen for a scrub,
 	 * since this would just restart the scrub we are already doing.
@@ -1135,12 +1158,11 @@ int
 vdev_validate(vdev_t *vd)
 {
 	spa_t *spa = vd->vdev_spa;
-	int c;
 	nvlist_t *label;
 	uint64_t guid, top_guid;
 	uint64_t state;
 
-	for (c = 0; c < vd->vdev_children; c++)
+	for (int c = 0; c < vd->vdev_children; c++)
 		if (vdev_validate(vd->vdev_child[c]) != 0)
 			return (EBADF);
 
@@ -1226,7 +1248,7 @@ vdev_close(vdev_t *vd)
 	vdev_cache_purge(vd);
 
 	/*
-	 * We record the previous state before we close it, so  that if we are
+	 * We record the previous state before we close it, so that if we are
 	 * doing a reopen(), we don't generate FMA ereports if we notice that
 	 * it's still faulted.
 	 */
@@ -1257,12 +1279,9 @@ vdev_reopen(vdev_t *vd)
 	if (vd->vdev_aux) {
 		(void) vdev_validate_aux(vd);
 		if (vdev_readable(vd) && vdev_writeable(vd) &&
-		    !l2arc_vdev_present(vd)) {
-			uint64_t size = vdev_get_rsize(vd);
-			l2arc_add_vdev(spa, vd,
-			    VDEV_LABEL_START_SIZE,
-			    size - VDEV_LABEL_START_SIZE);
-		}
+		    vd->vdev_aux == &spa->spa_l2cache &&
+		    !l2arc_vdev_present(vd))
+			l2arc_add_vdev(spa, vd);
 	} else {
 		(void) vdev_validate(vd);
 	}
@@ -1302,26 +1321,14 @@ vdev_create(vdev_t *vd, uint64_t txg, boolean_t isreplacing)
 	return (0);
 }
 
-/*
- * The is the latter half of vdev_create().  It is distinct because it
- * involves initiating transactions in order to do metaslab creation.
- * For creation, we want to try to create all vdevs at once and then undo it
- * if anything fails; this is much harder if we have pending transactions.
- */
 void
-vdev_init(vdev_t *vd, uint64_t txg)
+vdev_metaslab_set_size(vdev_t *vd)
 {
 	/*
 	 * Aim for roughly 200 metaslabs per vdev.
 	 */
 	vd->vdev_ms_shift = highbit(vd->vdev_asize / 200);
 	vd->vdev_ms_shift = MAX(vd->vdev_ms_shift, SPA_MAXBLOCKSHIFT);
-
-	/*
-	 * Initialize the vdev's metaslabs.  This can't fail because
-	 * there's nothing to read when creating all new metaslabs.
-	 */
-	VERIFY(vdev_metaslab_init(vd, txg) == 0);
 }
 
 void
@@ -1879,7 +1886,7 @@ vdev_degrade(spa_t *spa, uint64_t guid)
 int
 vdev_online(spa_t *spa, uint64_t guid, uint64_t flags, vdev_state_t *newstate)
 {
-	vdev_t *vd;
+	vdev_t *vd, *tvd, *pvd, *rvd = spa->spa_root_vdev;
 
 	spa_vdev_state_enter(spa);
 
@@ -1889,13 +1896,26 @@ vdev_online(spa_t *spa, uint64_t guid, uint64_t flags, vdev_state_t *newstate)
 	if (!vd->vdev_ops->vdev_op_leaf)
 		return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
 
+	tvd = vd->vdev_top;
 	vd->vdev_offline = B_FALSE;
 	vd->vdev_tmpoffline = B_FALSE;
 	vd->vdev_checkremove = !!(flags & ZFS_ONLINE_CHECKREMOVE);
 	vd->vdev_forcefault = !!(flags & ZFS_ONLINE_FORCEFAULT);
-	vdev_reopen(vd->vdev_top);
+
+	/* XXX - L2ARC 1.0 does not support expansion */
+	if (!vd->vdev_aux) {
+		for (pvd = vd; pvd != rvd; pvd = pvd->vdev_parent)
+			pvd->vdev_expanding = !!(flags & ZFS_ONLINE_EXPAND);
+	}
+
+	vdev_reopen(tvd);
 	vd->vdev_checkremove = vd->vdev_forcefault = B_FALSE;
 
+	if (!vd->vdev_aux) {
+		for (pvd = vd; pvd != rvd; pvd = pvd->vdev_parent)
+			pvd->vdev_expanding = B_FALSE;
+	}
+
 	if (newstate)
 		*newstate = vd->vdev_state;
 	if ((flags & ZFS_ONLINE_UNSPARE) &&
@@ -1904,13 +1924,21 @@ vdev_online(spa_t *spa, uint64_t guid, uint64_t flags, vdev_state_t *newstate)
 	    vd->vdev_parent->vdev_child[0] == vd)
 		vd->vdev_unspare = B_TRUE;
 
+	if ((flags & ZFS_ONLINE_EXPAND) || spa->spa_autoexpand) {
+
+		/* XXX - L2ARC 1.0 does not support expansion */
+		if (vd->vdev_aux)
+			return (spa_vdev_state_exit(spa, vd, ENOTSUP));
+		spa_async_request(spa, SPA_ASYNC_CONFIG_UPDATE);
+	}
 	return (spa_vdev_state_exit(spa, vd, 0));
 }
 
 int
 vdev_offline(spa_t *spa, uint64_t guid, uint64_t flags)
 {
-	vdev_t *vd;
+	vdev_t *vd, *tvd;
+	int error;
 
 	spa_vdev_state_enter(spa);
 
@@ -1920,34 +1948,58 @@ vdev_offline(spa_t *spa, uint64_t guid, uint64_t flags)
 	if (!vd->vdev_ops->vdev_op_leaf)
 		return (spa_vdev_state_exit(spa, NULL, ENOTSUP));
 
+	tvd = vd->vdev_top;
+
 	/*
 	 * If the device isn't already offline, try to offline it.
 	 */
 	if (!vd->vdev_offline) {
 		/*
 		 * If this device has the only valid copy of some data,
-		 * don't allow it to be offlined.
+		 * don't allow it to be offlined. Log devices are always
+		 * expendable.
 		 */
-		if (vd->vdev_aux == NULL && vdev_dtl_required(vd))
+		if (!tvd->vdev_islog && vd->vdev_aux == NULL &&
+		    vdev_dtl_required(vd))
 			return (spa_vdev_state_exit(spa, NULL, EBUSY));
 
 		/*
 		 * Offline this device and reopen its top-level vdev.
-		 * If this action results in the top-level vdev becoming
-		 * unusable, undo it and fail the request.
+		 * If the top-level vdev is a log device then just offline
+		 * it. Otherwise, if this action results in the top-level
+		 * vdev becoming unusable, undo it and fail the request.
 		 */
 		vd->vdev_offline = B_TRUE;
-		vdev_reopen(vd->vdev_top);
-		if (vd->vdev_aux == NULL && vdev_is_dead(vd->vdev_top)) {
+		vdev_reopen(tvd);
+
+		if (!tvd->vdev_islog && vd->vdev_aux == NULL &&
+		    vdev_is_dead(tvd)) {
 			vd->vdev_offline = B_FALSE;
-			vdev_reopen(vd->vdev_top);
+			vdev_reopen(tvd);
 			return (spa_vdev_state_exit(spa, NULL, EBUSY));
 		}
 	}
 
 	vd->vdev_tmpoffline = !!(flags & ZFS_OFFLINE_TEMPORARY);
 
-	return (spa_vdev_state_exit(spa, vd, 0));
+	if (!tvd->vdev_islog || !vdev_is_dead(tvd))
+		return (spa_vdev_state_exit(spa, vd, 0));
+
+	(void) spa_vdev_state_exit(spa, vd, 0);
+
+	error = dmu_objset_find(spa_name(spa), zil_vdev_offline,
+	    NULL, DS_FIND_CHILDREN);
+	if (error) {
+		(void) vdev_online(spa, guid, 0, NULL);
+		return (error);
+	}
+	/*
+	 * If we successfully offlined the log device then we need to
+	 * sync out the current txg so that the "stubby" block can be
+	 * removed by zil_sync().
+	 */
+	txg_wait_synced(spa->spa_dsl_pool, 0);
+	return (0);
 }
 
 /*
@@ -2062,7 +2114,9 @@ vdev_get_stats(vdev_t *vd, vdev_stat_t *vs)
 	vs->vs_scrub_errors = vd->vdev_spa->spa_scrub_errors;
 	vs->vs_timestamp = gethrtime() - vs->vs_timestamp;
 	vs->vs_state = vd->vdev_state;
-	vs->vs_rsize = vdev_get_rsize(vd);
+	vs->vs_rsize = vdev_get_min_asize(vd);
+	if (vd->vdev_ops->vdev_op_leaf)
+		vs->vs_rsize += VDEV_LABEL_START_SIZE + VDEV_LABEL_END_SIZE;
 	mutex_exit(&vd->vdev_stat_lock);
 
 	/*
@@ -2155,14 +2209,24 @@ vdev_stat_update(zio_t *zio, uint64_t psize)
 	if (flags & ZIO_FLAG_SPECULATIVE)
 		return;
 
+	/*
+	 * If this is an I/O error that is going to be retried, then ignore the
+	 * error.  Otherwise, the user may interpret B_FAILFAST I/O errors as
+	 * hard errors, when in reality they can happen for any number of
+	 * innocuous reasons (bus resets, MPxIO link failure, etc).
+	 */
+	if (zio->io_error == EIO &&
+	    !(zio->io_flags & ZIO_FLAG_IO_RETRY))
+		return;
+
 	mutex_enter(&vd->vdev_stat_lock);
-	if (type == ZIO_TYPE_READ) {
+	if (type == ZIO_TYPE_READ && !vdev_is_dead(vd)) {
 		if (zio->io_error == ECKSUM)
 			vs->vs_checksum_errors++;
 		else
 			vs->vs_read_errors++;
 	}
-	if (type == ZIO_TYPE_WRITE)
+	if (type == ZIO_TYPE_WRITE && !vdev_is_dead(vd))
 		vs->vs_write_errors++;
 	mutex_exit(&vd->vdev_stat_lock);
 
@@ -2205,10 +2269,9 @@ vdev_stat_update(zio_t *zio, uint64_t psize)
 void
 vdev_scrub_stat_update(vdev_t *vd, pool_scrub_type_t type, boolean_t complete)
 {
-	int c;
 	vdev_stat_t *vs = &vd->vdev_stat;
 
-	for (c = 0; c < vd->vdev_children; c++)
+	for (int c = 0; c < vd->vdev_children; c++)
 		vdev_scrub_stat_update(vd->vdev_child[c], type, complete);
 
 	mutex_enter(&vd->vdev_stat_lock);
@@ -2252,6 +2315,7 @@ vdev_space_update(vdev_t *vd, int64_t space_delta, int64_t alloc_delta,
 	 * childrens', thus not accurate enough for us.
 	 */
 	ASSERT((dspace_delta & (SPA_MINBLOCKSIZE-1)) == 0);
+	ASSERT(vd->vdev_deflate_ratio != 0 || vd->vdev_isl2cache);
 	dspace_delta = (dspace_delta >> SPA_MINBLOCKSHIFT) *
 	    vd->vdev_deflate_ratio;
 
@@ -2293,8 +2357,8 @@ vdev_config_dirty(vdev_t *vd)
 	int c;
 
 	/*
-	 * If this is an aux vdev (as with l2cache devices), then we update the
-	 * vdev config manually and set the sync flag.
+	 * If this is an aux vdev (as with l2cache and spare devices), then we
+	 * update the vdev config manually and set the sync flag.
 	 */
 	if (vd->vdev_aux != NULL) {
 		spa_aux_vdev_t *sav = vd->vdev_aux;
@@ -2316,8 +2380,11 @@ vdev_config_dirty(vdev_t *vd)
 
 		sav->sav_sync = B_TRUE;
 
-		VERIFY(nvlist_lookup_nvlist_array(sav->sav_config,
-		    ZPOOL_CONFIG_L2CACHE, &aux, &naux) == 0);
+		if (nvlist_lookup_nvlist_array(sav->sav_config,
+		    ZPOOL_CONFIG_L2CACHE, &aux, &naux) != 0) {
+			VERIFY(nvlist_lookup_nvlist_array(sav->sav_config,
+			    ZPOOL_CONFIG_SPARES, &aux, &naux) == 0);
+		}
 
 		ASSERT(c < naux);
 
@@ -2415,11 +2482,10 @@ vdev_propagate_state(vdev_t *vd)
 	vdev_t *rvd = spa->spa_root_vdev;
 	int degraded = 0, faulted = 0;
 	int corrupted = 0;
-	int c;
 	vdev_t *child;
 
 	if (vd->vdev_children > 0) {
-		for (c = 0; c < vd->vdev_children; c++) {
+		for (int c = 0; c < vd->vdev_children; c++) {
 			child = vd->vdev_child[c];
 
 			if (!vdev_readable(child) ||
@@ -2523,7 +2589,6 @@ vdev_set_state(vdev_t *vd, boolean_t isopen, vdev_state_t state, vdev_aux_t aux)
 		 * an error.
 		 */
 		if (spa->spa_load_state == SPA_LOAD_IMPORT &&
-		    !spa->spa_import_faulted &&
 		    vd->vdev_ops->vdev_op_leaf)
 			vd->vdev_not_present = 1;
 
@@ -2582,8 +2647,8 @@ vdev_set_state(vdev_t *vd, boolean_t isopen, vdev_state_t state, vdev_aux_t aux)
 		vd->vdev_removed = B_FALSE;
 	}
 
-	if (!isopen)
-		vdev_propagate_state(vd);
+	if (!isopen && vd->vdev_parent)
+		vdev_propagate_state(vd->vdev_parent);
 }
 
 /*
@@ -2595,8 +2660,6 @@ vdev_set_state(vdev_t *vd, boolean_t isopen, vdev_state_t state, vdev_aux_t aux)
 boolean_t
 vdev_is_bootable(vdev_t *vd)
 {
-	int c;
-
 	if (!vd->vdev_ops->vdev_op_leaf) {
 		char *vdev_type = vd->vdev_ops->vdev_op_type;
 
@@ -2611,9 +2674,53 @@ vdev_is_bootable(vdev_t *vd)
 		return (B_FALSE);
 	}
 
-	for (c = 0; c < vd->vdev_children; c++) {
+	for (int c = 0; c < vd->vdev_children; c++) {
 		if (!vdev_is_bootable(vd->vdev_child[c]))
 			return (B_FALSE);
 	}
 	return (B_TRUE);
 }
+
+void
+vdev_load_log_state(vdev_t *vd, nvlist_t *nv)
+{
+	uint_t children;
+	nvlist_t **child;
+	uint64_t val;
+	spa_t *spa = vd->vdev_spa;
+
+	if (nvlist_lookup_nvlist_array(nv, ZPOOL_CONFIG_CHILDREN,
+	    &child, &children) == 0) {
+		for (int c = 0; c < children; c++)
+			vdev_load_log_state(vd->vdev_child[c], child[c]);
+	}
+
+	if (vd->vdev_ops->vdev_op_leaf && nvlist_lookup_uint64(nv,
+	    ZPOOL_CONFIG_OFFLINE, &val) == 0 && val) {
+
+		/*
+		 * It would be nice to call vdev_offline()
+		 * directly but the pool isn't fully loaded and
+		 * the txg threads have not been started yet.
+		 */
+		spa_config_enter(spa, SCL_STATE_ALL, FTAG, RW_WRITER);
+		vd->vdev_offline = val;
+		vdev_reopen(vd->vdev_top);
+		spa_config_exit(spa, SCL_STATE_ALL, FTAG);
+	}
+}
+
+/*
+ * Expand a vdev if possible.
+ */
+void
+vdev_expand(vdev_t *vd, uint64_t txg)
+{
+	ASSERT(vd->vdev_top == vd);
+	ASSERT(spa_config_held(vd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
+
+	if ((vd->vdev_asize >> vd->vdev_ms_shift) > vd->vdev_ms_count) {
+		VERIFY(vdev_metaslab_init(vd, txg) == 0);
+		vdev_config_dirty(vd);
+	}
+}
diff --git a/module/zfs/vdev_label.c b/module/zfs/vdev_label.c
index f61de3c4e..48d5fc232 100644
--- a/module/zfs/vdev_label.c
+++ b/module/zfs/vdev_label.c
@@ -233,6 +233,10 @@ vdev_config_generate(spa_t *spa, vdev_t *vd, boolean_t getstats,
 		VERIFY(nvlist_add_string(nv, ZPOOL_CONFIG_PHYS_PATH,
 		    vd->vdev_physpath) == 0);
 
+	if (vd->vdev_fru != NULL)
+		VERIFY(nvlist_add_string(nv, ZPOOL_CONFIG_FRU,
+		    vd->vdev_fru) == 0);
+
 	if (vd->vdev_nparity != 0) {
 		ASSERT(strcmp(vd->vdev_ops->vdev_op_type,
 		    VDEV_TYPE_RAIDZ) == 0);
@@ -335,8 +339,8 @@ vdev_label_read_config(vdev_t *vd)
 	nvlist_t *config = NULL;
 	vdev_phys_t *vp;
 	zio_t *zio;
-	int flags =
-	    ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE;
+	int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL |
+	    ZIO_FLAG_SPECULATIVE;
 
 	ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
 
@@ -345,6 +349,7 @@ vdev_label_read_config(vdev_t *vd)
 
 	vp = zio_buf_alloc(sizeof (vdev_phys_t));
 
+retry:
 	for (int l = 0; l < VDEV_LABELS; l++) {
 
 		zio = zio_root(spa, NULL, NULL, flags);
@@ -364,6 +369,11 @@ vdev_label_read_config(vdev_t *vd)
 		}
 	}
 
+	if (config == NULL && !(flags & ZIO_FLAG_TRYHARD)) {
+		flags |= ZIO_FLAG_TRYHARD;
+		goto retry;
+	}
+
 	zio_buf_free(vp, sizeof (vdev_phys_t));
 
 	return (config);
@@ -488,7 +498,7 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
 	spa_t *spa = vd->vdev_spa;
 	nvlist_t *label;
 	vdev_phys_t *vp;
-	vdev_boot_header_t *vb;
+	char *pad2;
 	uberblock_t *ub;
 	zio_t *zio;
 	char *buf;
@@ -630,16 +640,6 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
 	}
 
 	/*
-	 * Initialize boot block header.
-	 */
-	vb = zio_buf_alloc(sizeof (vdev_boot_header_t));
-	bzero(vb, sizeof (vdev_boot_header_t));
-	vb->vb_magic = VDEV_BOOT_MAGIC;
-	vb->vb_version = VDEV_BOOT_VERSION;
-	vb->vb_offset = VDEV_BOOT_OFFSET;
-	vb->vb_size = VDEV_BOOT_SIZE;
-
-	/*
 	 * Initialize uberblock template.
 	 */
 	ub = zio_buf_alloc(VDEV_UBERBLOCK_SIZE(vd));
@@ -647,9 +647,14 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
 	*ub = spa->spa_uberblock;
 	ub->ub_txg = 0;
 
+	/* Initialize the 2nd padding area. */
+	pad2 = zio_buf_alloc(VDEV_PAD_SIZE);
+	bzero(pad2, VDEV_PAD_SIZE);
+
 	/*
 	 * Write everything in parallel.
 	 */
+retry:
 	zio = zio_root(spa, NULL, NULL, flags);
 
 	for (int l = 0; l < VDEV_LABELS; l++) {
@@ -658,9 +663,14 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
 		    offsetof(vdev_label_t, vl_vdev_phys),
 		    sizeof (vdev_phys_t), NULL, NULL, flags);
 
-		vdev_label_write(zio, vd, l, vb,
-		    offsetof(vdev_label_t, vl_boot_header),
-		    sizeof (vdev_boot_header_t), NULL, NULL, flags);
+		/*
+		 * Skip the 1st padding area.
+		 * Zero out the 2nd padding area where it might have
+		 * left over data from previous filesystem format.
+		 */
+		vdev_label_write(zio, vd, l, pad2,
+		    offsetof(vdev_label_t, vl_pad2),
+		    VDEV_PAD_SIZE, NULL, NULL, flags);
 
 		for (int n = 0; n < VDEV_UBERBLOCK_COUNT(vd); n++) {
 			vdev_label_write(zio, vd, l, ub,
@@ -671,9 +681,14 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
 
 	error = zio_wait(zio);
 
+	if (error != 0 && !(flags & ZIO_FLAG_TRYHARD)) {
+		flags |= ZIO_FLAG_TRYHARD;
+		goto retry;
+	}
+
 	nvlist_free(label);
+	zio_buf_free(pad2, VDEV_PAD_SIZE);
 	zio_buf_free(ub, VDEV_UBERBLOCK_SIZE(vd));
-	zio_buf_free(vb, sizeof (vdev_boot_header_t));
 	zio_buf_free(vp, sizeof (vdev_phys_t));
 
 	/*
@@ -757,8 +772,8 @@ vdev_uberblock_load(zio_t *zio, vdev_t *vd, uberblock_t *ubbest)
 {
 	spa_t *spa = vd->vdev_spa;
 	vdev_t *rvd = spa->spa_root_vdev;
-	int flags =
-	    ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE;
+	int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL |
+	    ZIO_FLAG_SPECULATIVE | ZIO_FLAG_TRYHARD;
 
 	if (vd == rvd) {
 		ASSERT(zio == NULL);
@@ -996,7 +1011,7 @@ vdev_label_sync_list(spa_t *spa, int l, uint64_t txg, int flags)
  * at any time, you can just call it again, and it will resume its work.
  */
 int
-vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg)
+vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg, boolean_t tryhard)
 {
 	spa_t *spa = svd[0]->vdev_spa;
 	uberblock_t *ub = &spa->spa_uberblock;
@@ -1005,6 +1020,16 @@ vdev_config_sync(vdev_t **svd, int svdcount, uint64_t txg)
 	int error;
 	int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL;
 
+	/*
+	 * Normally, we don't want to try too hard to write every label and
+	 * uberblock.  If there is a flaky disk, we don't want the rest of the
+	 * sync process to block while we retry.  But if we can't write a
+	 * single label out, we should retry with ZIO_FLAG_TRYHARD before
+	 * bailing out and declaring the pool faulted.
+	 */
+	if (tryhard)
+		flags |= ZIO_FLAG_TRYHARD;
+
 	ASSERT(ub->ub_txg <= txg);
 
 	/*
diff --git a/module/zfs/vdev_queue.c b/module/zfs/vdev_queue.c
index 4e3c20acd..5e57a1513 100644
--- a/module/zfs/vdev_queue.c
+++ b/module/zfs/vdev_queue.c
@@ -48,10 +48,11 @@ int zfs_vdev_time_shift = 6;
 int zfs_vdev_ramp_rate = 2;
 
 /*
- * i/os will be aggregated into a single large i/o up to
- * zfs_vdev_aggregation_limit bytes long.
+ * To reduce IOPs, we aggregate small adjacent i/os into one large i/o.
+ * For read i/os, we also aggregate across small adjacency gaps.
  */
 int zfs_vdev_aggregation_limit = SPA_MAXBLOCKSIZE;
+int zfs_vdev_read_gap_limit = 32 << 10;
 
 /*
  * Virtual device vector for disk I/O scheduling.
@@ -159,16 +160,23 @@ vdev_queue_agg_io_done(zio_t *aio)
 	zio_buf_free(aio->io_data, aio->io_size);
 }
 
-#define	IS_ADJACENT(io, nio) \
-	((io)->io_offset + (io)->io_size == (nio)->io_offset)
+/*
+ * Compute the range spanned by two i/os, which is the endpoint of the last
+ * (lio->io_offset + lio->io_size) minus start of the first (fio->io_offset).
+ * Conveniently, the gap between fio and lio is given by -IO_SPAN(lio, fio);
+ * thus fio and lio are adjacent if and only if IO_SPAN(lio, fio) == 0.
+ */
+#define	IO_SPAN(fio, lio) ((lio)->io_offset + (lio)->io_size - (fio)->io_offset)
+#define	IO_GAP(fio, lio) (-IO_SPAN(lio, fio))
 
 static zio_t *
 vdev_queue_io_to_issue(vdev_queue_t *vq, uint64_t pending_limit)
 {
 	zio_t *fio, *lio, *aio, *dio, *nio;
 	avl_tree_t *t;
-	uint64_t size;
 	int flags;
+	uint64_t maxspan = zfs_vdev_aggregation_limit;
+	uint64_t maxgap;
 
 	ASSERT(MUTEX_HELD(&vq->vq_lock));
 
@@ -179,8 +187,8 @@ vdev_queue_io_to_issue(vdev_queue_t *vq, uint64_t pending_limit)
 	fio = lio = avl_first(&vq->vq_deadline_tree);
 
 	t = fio->io_vdev_tree;
-	size = fio->io_size;
 	flags = fio->io_flags & ZIO_FLAG_AGG_INHERIT;
+	maxgap = (t == &vq->vq_read_tree) ? zfs_vdev_read_gap_limit : 0;
 
 	if (!(flags & ZIO_FLAG_DONT_AGGREGATE)) {
 		/*
@@ -191,22 +199,18 @@ vdev_queue_io_to_issue(vdev_queue_t *vq, uint64_t pending_limit)
 		 * scrub/resilver, can be preserved in the aggregate.
 		 */
 		while ((dio = AVL_PREV(t, fio)) != NULL &&
-		    IS_ADJACENT(dio, fio) &&
 		    (dio->io_flags & ZIO_FLAG_AGG_INHERIT) == flags &&
-		    size + dio->io_size <= zfs_vdev_aggregation_limit) {
+		    IO_SPAN(dio, lio) <= maxspan && IO_GAP(dio, fio) <= maxgap)
 			fio = dio;
-			size += dio->io_size;
-		}
+
 		while ((dio = AVL_NEXT(t, lio)) != NULL &&
-		    IS_ADJACENT(lio, dio) &&
 		    (dio->io_flags & ZIO_FLAG_AGG_INHERIT) == flags &&
-		    size + dio->io_size <= zfs_vdev_aggregation_limit) {
+		    IO_SPAN(fio, dio) <= maxspan && IO_GAP(lio, dio) <= maxgap)
 			lio = dio;
-			size += dio->io_size;
-		}
 	}
 
 	if (fio != lio) {
+		uint64_t size = IO_SPAN(fio, lio);
 		ASSERT(size <= zfs_vdev_aggregation_limit);
 
 		aio = zio_vdev_delegated_io(fio->io_vd, fio->io_offset,
@@ -214,9 +218,10 @@ vdev_queue_io_to_issue(vdev_queue_t *vq, uint64_t pending_limit)
 		    flags | ZIO_FLAG_DONT_CACHE | ZIO_FLAG_DONT_QUEUE,
 		    vdev_queue_agg_io_done, NULL);
 
-		/* We want to process lio, then stop */
-		lio = AVL_NEXT(t, lio);
-		for (dio = fio; dio != lio; dio = nio) {
+		nio = fio;
+		do {
+			dio = nio;
+			nio = AVL_NEXT(t, dio);
 			ASSERT(dio->io_type == aio->io_type);
 			ASSERT(dio->io_vdev_tree == t);
 
@@ -224,13 +229,12 @@ vdev_queue_io_to_issue(vdev_queue_t *vq, uint64_t pending_limit)
 				bcopy(dio->io_data, (char *)aio->io_data +
 				    (dio->io_offset - aio->io_offset),
 				    dio->io_size);
-			nio = AVL_NEXT(t, dio);
 
 			zio_add_child(dio, aio);
 			vdev_queue_io_remove(vq, dio);
 			zio_vdev_io_bypass(dio);
 			zio_execute(dio);
-		}
+		} while (dio != lio);
 
 		avl_add(&vq->vq_pending_tree, aio);
 
diff --git a/module/zfs/vdev_raidz.c b/module/zfs/vdev_raidz.c
index ad997f528..92753d871 100644
--- a/module/zfs/vdev_raidz.c
+++ b/module/zfs/vdev_raidz.c
@@ -20,7 +20,7 @@
  */
 
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -697,7 +697,7 @@ vdev_raidz_io_start(zio_t *zio)
 			continue;
 		}
 		if (c >= rm->rm_firstdatacol || rm->rm_missingdata > 0 ||
-		    (zio->io_flags & ZIO_FLAG_SCRUB)) {
+		    (zio->io_flags & (ZIO_FLAG_SCRUB | ZIO_FLAG_RESILVER))) {
 			zio_nowait(zio_vdev_child_io(zio, NULL, cvd,
 			    rc->rc_offset, rc->rc_data, rc->rc_size,
 			    zio->io_type, zio->io_priority, 0,
diff --git a/module/zfs/zap.c b/module/zfs/zap.c
index ca859ec35..2dc2705b9 100644
--- a/module/zfs/zap.c
+++ b/module/zfs/zap.c
@@ -19,13 +19,10 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
-
 /*
  * This file contains the top half of the zfs directory structure
  * implementation. The bottom half is in zap_leaf.c.
@@ -45,6 +42,7 @@
 #include <sys/dmu.h>
 #include <sys/zfs_context.h>
 #include <sys/zfs_znode.h>
+#include <sys/fs/zfs.h>
 #include <sys/zap.h>
 #include <sys/refcount.h>
 #include <sys/zap_impl.h>
@@ -1134,3 +1132,58 @@ fzap_get_stats(zap_t *zap, zap_stats_t *zs)
 		}
 	}
 }
+
+int
+fzap_count_write(zap_name_t *zn, int add, uint64_t *towrite,
+    uint64_t *tooverwrite)
+{
+	zap_t *zap = zn->zn_zap;
+	zap_leaf_t *l;
+	int err;
+
+	/*
+	 * Account for the header block of the fatzap.
+	 */
+	if (!add && dmu_buf_freeable(zap->zap_dbuf)) {
+		tooverwrite += zap->zap_dbuf->db_size;
+	} else {
+		towrite += zap->zap_dbuf->db_size;
+	}
+
+	/*
+	 * Account for the pointer table blocks.
+	 * If we are adding we need to account for the following cases :
+	 * - If the pointer table is embedded, this operation could force an
+	 *   external pointer table.
+	 * - If this already has an external pointer table this operation
+	 *   could extend the table.
+	 */
+	if (add) {
+		if (zap->zap_f.zap_phys->zap_ptrtbl.zt_blk == 0)
+			towrite += zap->zap_dbuf->db_size;
+		else
+			towrite += (zap->zap_dbuf->db_size * 3);
+	}
+
+	/*
+	 * Now, check if the block containing leaf is freeable
+	 * and account accordingly.
+	 */
+	err = zap_deref_leaf(zap, zn->zn_hash, NULL, RW_READER, &l);
+	if (err != 0) {
+		return (err);
+	}
+
+	if (!add && dmu_buf_freeable(l->l_dbuf)) {
+		tooverwrite += l->l_dbuf->db_size;
+	} else {
+		/*
+		 * If this an add operation, the leaf block could split.
+		 * Hence, we need to account for an additional leaf block.
+		 */
+		towrite += (add ? 2 : 1) * l->l_dbuf->db_size;
+	}
+
+	zap_put_leaf(l);
+	return (0);
+}
diff --git a/module/zfs/zap_leaf.c b/module/zfs/zap_leaf.c
index da498b6bc..9d8354e73 100644
--- a/module/zfs/zap_leaf.c
+++ b/module/zfs/zap_leaf.c
@@ -19,24 +19,23 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 /*
  * The 512-byte leaf is broken into 32 16-byte chunks.
  * chunk number n means l_chunk[n], even though the header precedes it.
  * the names are stored null-terminated.
  */
 
+#include <sys/spa.h>
+#include <sys/dmu.h>
 #include <sys/zfs_context.h>
+#include <sys/fs/zfs.h>
 #include <sys/zap.h>
 #include <sys/zap_impl.h>
 #include <sys/zap_leaf.h>
-#include <sys/spa.h>
-#include <sys/dmu.h>
 
 static uint16_t *zap_leaf_rehash_entry(zap_leaf_t *l, uint16_t entry);
 
diff --git a/module/zfs/zap_micro.c b/module/zfs/zap_micro.c
index abba42775..fbc93b423 100644
--- a/module/zfs/zap_micro.c
+++ b/module/zfs/zap_micro.c
@@ -19,12 +19,10 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include <sys/spa.h>
 #include <sys/dmu.h>
 #include <sys/zfs_context.h>
@@ -78,8 +76,8 @@ zap_normalize(zap_t *zap, const char *name, char *namenorm)
 
 	err = 0;
 	(void) u8_textprep_str((char *)name, &inlen, namenorm, &outlen,
-	    zap->zap_normflags | U8_TEXTPREP_IGNORE_NULL, U8_UNICODE_LATEST,
-	    &err);
+	    zap->zap_normflags | U8_TEXTPREP_IGNORE_NULL |
+	    U8_TEXTPREP_IGNORE_INVALID, U8_UNICODE_LATEST, &err);
 
 	return (err);
 }
@@ -1067,3 +1065,79 @@ zap_get_stats(objset_t *os, uint64_t zapobj, zap_stats_t *zs)
 	zap_unlockdir(zap);
 	return (0);
 }
+
+int
+zap_count_write(objset_t *os, uint64_t zapobj, const char *name, int add,
+    uint64_t *towrite, uint64_t *tooverwrite, uint64_t dn_datablkshift)
+{
+	zap_t *zap;
+	int err = 0;
+
+
+	/*
+	 * Since, we don't have a name, we cannot figure out which blocks will
+	 * be affected in this operation. So, account for the worst case :
+	 * - 3 blocks overwritten: target leaf, ptrtbl block, header block
+	 * - 4 new blocks written if adding:
+	 * 	- 2 blocks for possibly split leaves,
+	 * 	- 2 grown ptrtbl blocks
+	 *
+	 * This also accomodates the case where an add operation to a fairly
+	 * large microzap results in a promotion to fatzap.
+	 */
+	if (name == NULL) {
+		*towrite += (3 + (add ? 4 : 0)) * SPA_MAXBLOCKSIZE;
+		return (err);
+	}
+
+	/*
+	 * We lock the zap with adding ==  FALSE. Because, if we pass
+	 * the actual value of add, it could trigger a mzap_upgrade().
+	 * At present we are just evaluating the possibility of this operation
+	 * and hence we donot want to trigger an upgrade.
+	 */
+	err = zap_lockdir(os, zapobj, NULL, RW_READER, TRUE, FALSE, &zap);
+	if (err)
+		return (err);
+
+	if (!zap->zap_ismicro) {
+		zap_name_t *zn = zap_name_alloc(zap, name, MT_EXACT);
+		if (zn) {
+			err = fzap_count_write(zn, add, towrite,
+			    tooverwrite);
+			zap_name_free(zn);
+		} else {
+			/*
+			 * We treat this case as similar to (name == NULL)
+			 */
+			*towrite += (3 + (add ? 4 : 0)) * SPA_MAXBLOCKSIZE;
+		}
+	} else {
+		if (!add) {
+			if (dmu_buf_freeable(zap->zap_dbuf))
+				*tooverwrite += SPA_MAXBLOCKSIZE;
+			else
+				*towrite += SPA_MAXBLOCKSIZE;
+		} else {
+			/*
+			 * We are here if we are adding and (name != NULL).
+			 * It is hard to find out if this add will promote this
+			 * microzap to fatzap. Hence, we assume the worst case
+			 * and account for the blocks assuming this microzap
+			 * would be promoted to a fatzap.
+			 *
+			 * 1 block overwritten  : header block
+			 * 4 new blocks written : 2 new split leaf, 2 grown
+			 *			ptrtbl blocks
+			 */
+			if (dmu_buf_freeable(zap->zap_dbuf))
+				*tooverwrite += 1 << dn_datablkshift;
+			else
+				*towrite += 1 << dn_datablkshift;
+			*towrite += 4 << dn_datablkshift;
+		}
+	}
+
+	zap_unlockdir(zap);
+	return (err);
+}
diff --git a/module/zfs/zfs_acl.c b/module/zfs/zfs_acl.c
index fdf92a156..734bd8395 100644
--- a/module/zfs/zfs_acl.c
+++ b/module/zfs/zfs_acl.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -65,15 +65,16 @@
     ACE_WRITE_ATTRIBUTES|ACE_WRITE_NAMED_ATTRS)
 #define	OWNER_ALLOW_MASK (ACE_WRITE_ACL | ACE_WRITE_OWNER | \
     ACE_WRITE_ATTRIBUTES|ACE_WRITE_NAMED_ATTRS)
-#define	WRITE_MASK_DATA (ACE_WRITE_DATA|ACE_APPEND_DATA|ACE_WRITE_NAMED_ATTRS)
 
 #define	ZFS_CHECKED_MASKS (ACE_READ_ACL|ACE_READ_ATTRIBUTES|ACE_READ_DATA| \
     ACE_READ_NAMED_ATTRS|ACE_WRITE_DATA|ACE_WRITE_ATTRIBUTES| \
     ACE_WRITE_NAMED_ATTRS|ACE_APPEND_DATA|ACE_EXECUTE|ACE_WRITE_OWNER| \
     ACE_WRITE_ACL|ACE_DELETE|ACE_DELETE_CHILD|ACE_SYNCHRONIZE)
 
-#define	WRITE_MASK (WRITE_MASK_DATA|ACE_WRITE_ATTRIBUTES|ACE_WRITE_ACL|\
-    ACE_WRITE_OWNER|ACE_DELETE|ACE_DELETE_CHILD)
+#define	WRITE_MASK_DATA (ACE_WRITE_DATA|ACE_APPEND_DATA|ACE_WRITE_NAMED_ATTRS)
+#define	WRITE_MASK_ATTRS (ACE_WRITE_ACL|ACE_WRITE_OWNER|ACE_WRITE_ATTRIBUTES| \
+    ACE_DELETE|ACE_DELETE_CHILD)
+#define	WRITE_MASK (WRITE_MASK_DATA|WRITE_MASK_ATTRS)
 
 #define	OGE_CLEAR	(ACE_READ_DATA|ACE_LIST_DIRECTORY|ACE_WRITE_DATA| \
     ACE_ADD_FILE|ACE_APPEND_DATA|ACE_ADD_SUBDIRECTORY|ACE_EXECUTE)
@@ -538,8 +539,9 @@ zfs_acl_curr_node(zfs_acl_t *aclp)
  * ACE FUIDs will be created later.
  */
 int
-zfs_copy_ace_2_fuid(vtype_t obj_type, zfs_acl_t *aclp, void *datap,
-    zfs_ace_t *z_acl, int aclcnt, size_t *size)
+zfs_copy_ace_2_fuid(zfsvfs_t *zfsvfs, vtype_t obj_type, zfs_acl_t *aclp,
+    void *datap, zfs_ace_t *z_acl, int aclcnt, size_t *size,
+    zfs_fuid_info_t **fuidp, cred_t *cr)
 {
 	int i;
 	uint16_t entry_type;
@@ -555,9 +557,9 @@ zfs_copy_ace_2_fuid(vtype_t obj_type, zfs_acl_t *aclp, void *datap,
 		entry_type = aceptr->z_hdr.z_flags & ACE_TYPE_FLAGS;
 		if (entry_type != ACE_OWNER && entry_type != OWNING_GROUP &&
 		    entry_type != ACE_EVERYONE) {
-			if (!aclp->z_has_fuids)
-				aclp->z_has_fuids = IS_EPHEMERAL(acep->a_who);
-			aceptr->z_fuid = (uint64_t)acep->a_who;
+			aceptr->z_fuid = zfs_fuid_create(zfsvfs, acep->a_who,
+			    cr, (entry_type == 0) ?
+			    ZFS_ACE_USER : ZFS_ACE_GROUP, fuidp);
 		}
 
 		/*
@@ -682,7 +684,7 @@ zfs_copy_ace_2_oldace(vtype_t obj_type, zfs_acl_t *aclp, ace_t *acep,
  * convert old ACL format to new
  */
 void
-zfs_acl_xform(znode_t *zp, zfs_acl_t *aclp)
+zfs_acl_xform(znode_t *zp, zfs_acl_t *aclp, cred_t *cr)
 {
 	zfs_oldace_t *oldaclp;
 	int i;
@@ -714,9 +716,9 @@ zfs_acl_xform(znode_t *zp, zfs_acl_t *aclp)
 	newaclnode = zfs_acl_node_alloc(aclp->z_acl_count *
 	    sizeof (zfs_object_ace_t));
 	aclp->z_ops = zfs_acl_fuid_ops;
-	VERIFY(zfs_copy_ace_2_fuid(ZTOV(zp)->v_type, aclp, oldaclp,
-	    newaclnode->z_acldata, aclp->z_acl_count,
-	    &newaclnode->z_size) == 0);
+	VERIFY(zfs_copy_ace_2_fuid(zp->z_zfsvfs, ZTOV(zp)->v_type, aclp,
+	    oldaclp, newaclnode->z_acldata, aclp->z_acl_count,
+	    &newaclnode->z_size, NULL, cr) == 0);
 	newaclnode->z_ace_count = aclp->z_acl_count;
 	aclp->z_version = ZFS_ACL_VERSION;
 	kmem_free(oldaclp, aclp->z_acl_count * sizeof (zfs_oldace_t));
@@ -770,8 +772,7 @@ zfs_set_ace(zfs_acl_t *aclp, void *acep, uint32_t access_mask,
  * Also, create FUIDs for any User/Group ACEs
  */
 static uint64_t
-zfs_mode_fuid_compute(znode_t *zp, zfs_acl_t *aclp, cred_t *cr,
-    zfs_fuid_info_t **fuidp, dmu_tx_t *tx)
+zfs_mode_compute(znode_t *zp, zfs_acl_t *aclp)
 {
 	int		entry_type;
 	mode_t		mode;
@@ -905,15 +906,6 @@ zfs_mode_fuid_compute(znode_t *zp, zfs_acl_t *aclp, cred_t *cr,
 				}
 			}
 		}
-		/*
-		 * Now handle FUID create for user/group ACEs
-		 */
-		if (entry_type == 0 || entry_type == ACE_IDENTIFIER_GROUP) {
-			aclp->z_ops.ace_who_set(acep,
-			    zfs_fuid_create(zp->z_zfsvfs, who, cr,
-			    (entry_type == 0) ? ZFS_ACE_USER : ZFS_ACE_GROUP,
-			    tx, fuidp));
-		}
 	}
 	return (mode);
 }
@@ -989,7 +981,7 @@ zfs_acl_node_read(znode_t *zp, zfs_acl_t **aclpp, boolean_t will_modify)
 	aclnode = zfs_acl_node_alloc(aclsize);
 	list_insert_head(&aclp->z_acl, aclnode);
 	error = dmu_read(zp->z_zfsvfs->z_os, extacl, 0,
-	    aclsize, aclnode->z_acldata);
+	    aclsize, aclnode->z_acldata, DMU_READ_PREFETCH);
 	aclnode->z_ace_count = acl_count;
 	aclp->z_acl_count = acl_count;
 	aclp->z_acl_bytes = aclsize;
@@ -1014,8 +1006,7 @@ zfs_acl_node_read(znode_t *zp, zfs_acl_t **aclpp, boolean_t will_modify)
  * already checked the acl and knows whether to inherit.
  */
 int
-zfs_aclset_common(znode_t *zp, zfs_acl_t *aclp, cred_t *cr,
-    zfs_fuid_info_t **fuidp, dmu_tx_t *tx)
+zfs_aclset_common(znode_t *zp, zfs_acl_t *aclp, cred_t *cr, dmu_tx_t *tx)
 {
 	int		error;
 	znode_phys_t	*zphys = zp->z_phys;
@@ -1026,12 +1017,9 @@ zfs_aclset_common(znode_t *zp, zfs_acl_t *aclp, cred_t *cr,
 	dmu_object_type_t otype;
 	zfs_acl_node_t	*aclnode;
 
-	ASSERT(MUTEX_HELD(&zp->z_lock));
-	ASSERT(MUTEX_HELD(&zp->z_acl_lock));
-
 	dmu_buf_will_dirty(zp->z_dbuf, tx);
 
-	zphys->zp_mode = zfs_mode_fuid_compute(zp, aclp, cr, fuidp, tx);
+	zphys->zp_mode = zfs_mode_compute(zp, aclp);
 
 	/*
 	 * Decide which opbject type to use.  If we are forced to
@@ -1043,7 +1031,7 @@ zfs_aclset_common(znode_t *zp, zfs_acl_t *aclp, cred_t *cr,
 	} else {
 		if ((aclp->z_version == ZFS_ACL_VERSION_INITIAL) &&
 		    (zfsvfs->z_version >= ZPL_VERSION_FUID))
-			zfs_acl_xform(zp, aclp);
+			zfs_acl_xform(zp, aclp, cr);
 		ASSERT(aclp->z_version >= ZFS_ACL_VERSION_FUID);
 		otype = DMU_OT_ACL;
 	}
@@ -1125,7 +1113,6 @@ zfs_aclset_common(znode_t *zp, zfs_acl_t *aclp, cred_t *cr,
 	if (ace_trivial_common(aclp, 0, zfs_ace_walk) == 0)
 		zp->z_phys->zp_flags |= ZFS_ACL_TRIVIAL;
 
-	zfs_time_stamper_locked(zp, STATE_CHANGED, tx);
 	return (0);
 }
 
@@ -1336,7 +1323,7 @@ zfs_acl_ace_insert(zfs_acl_t *aclp, void  *acep)
  * Prepend deny ACE
  */
 static void *
-zfs_acl_prepend_deny(znode_t *zp, zfs_acl_t *aclp, void *acep,
+zfs_acl_prepend_deny(uint64_t uid, zfs_acl_t *aclp, void *acep,
     mode_t mode)
 {
 	zfs_acl_node_t *aclnode;
@@ -1349,7 +1336,7 @@ zfs_acl_prepend_deny(znode_t *zp, zfs_acl_t *aclp, void *acep,
 	fuid = aclp->z_ops.ace_who_get(acep);
 	flags = aclp->z_ops.ace_flags_get(acep);
 	zfs_set_ace(aclp, newacep, 0, DENY, fuid, (flags & ACE_TYPE_FLAGS));
-	zfs_acl_prepend_fixup(aclp, newacep, acep, mode, zp->z_phys->zp_uid);
+	zfs_acl_prepend_fixup(aclp, newacep, acep, mode, uid);
 
 	return (newacep);
 }
@@ -1473,9 +1460,9 @@ zfs_fixup_group_entries(zfs_acl_t *aclp, void *acep, void *prevacep,
  * in PSARC/2002/240
  */
 static void
-zfs_acl_chmod(znode_t *zp, uint64_t mode, zfs_acl_t *aclp)
+zfs_acl_chmod(zfsvfs_t *zfsvfs, uint64_t uid,
+    uint64_t mode, zfs_acl_t *aclp)
 {
-	zfsvfs_t	*zfsvfs = zp->z_zfsvfs;
 	void		*acep = NULL, *prevacep = NULL;
 	uint64_t	who;
 	int 		i;
@@ -1485,11 +1472,6 @@ zfs_acl_chmod(znode_t *zp, uint64_t mode, zfs_acl_t *aclp)
 	uint16_t	iflags, type;
 	uint32_t	access_mask;
 
-	ASSERT(MUTEX_HELD(&zp->z_acl_lock));
-	ASSERT(MUTEX_HELD(&zp->z_lock));
-
-	aclp->z_hints = (zp->z_phys->zp_flags & V4_ACL_WIDE_FLAGS);
-
 	/*
 	 * If discard then just discard all ACL nodes which
 	 * represent the ACEs.
@@ -1554,17 +1536,15 @@ zfs_acl_chmod(znode_t *zp, uint64_t mode, zfs_acl_t *aclp)
 
 					if (!reuse_deny) {
 						prevacep =
-						    zfs_acl_prepend_deny(zp,
+						    zfs_acl_prepend_deny(uid,
 						    aclp, acep, mode);
 					} else {
 						zfs_acl_prepend_fixup(
 						    aclp, prevacep,
-						    acep, mode,
-						    zp->z_phys->zp_uid);
+						    acep, mode, uid);
 					}
 					zfs_fixup_group_entries(aclp, acep,
 					    prevacep, mode);
-
 				}
 			}
 		}
@@ -1623,8 +1603,10 @@ zfs_acl_chmod_setattr(znode_t *zp, zfs_acl_t **aclp, uint64_t mode)
 	mutex_enter(&zp->z_acl_lock);
 	*aclp = NULL;
 	error = zfs_acl_node_read(zp, aclp, B_TRUE);
-	if (error == 0)
-		zfs_acl_chmod(zp, mode, *aclp);
+	if (error == 0) {
+		(*aclp)->z_hints = zp->z_phys->zp_flags & V4_ACL_WIDE_FLAGS;
+		zfs_acl_chmod(zp->z_zfsvfs, zp->z_phys->zp_uid, mode, *aclp);
+	}
 	mutex_exit(&zp->z_acl_lock);
 	mutex_exit(&zp->z_lock);
 	return (error);
@@ -1649,9 +1631,8 @@ zfs_restricted_update(zfsvfs_t *zfsvfs, zfs_acl_t *aclp, void *acep)
  * Should ACE be inherited?
  */
 static int
-zfs_ace_can_use(znode_t *zp, uint16_t acep_flags)
+zfs_ace_can_use(vtype_t vtype, uint16_t acep_flags)
 {
-	int vtype = ZTOV(zp)->v_type;
 	int	iflags = (acep_flags & 0xf);
 
 	if ((vtype == VDIR) && (iflags & ACE_DIRECTORY_INHERIT_ACE))
@@ -1666,10 +1647,9 @@ zfs_ace_can_use(znode_t *zp, uint16_t acep_flags)
  * inherit inheritable ACEs from parent
  */
 static zfs_acl_t *
-zfs_acl_inherit(znode_t *zp, zfs_acl_t *paclp, uint64_t mode,
-    boolean_t *need_chmod)
+zfs_acl_inherit(zfsvfs_t *zfsvfs, vtype_t vtype, zfs_acl_t *paclp,
+    uint64_t mode, boolean_t *need_chmod)
 {
-	zfsvfs_t	*zfsvfs = zp->z_zfsvfs;
 	void		*pacep;
 	void		*acep, *acep2;
 	zfs_acl_node_t  *aclnode, *aclnode2;
@@ -1680,8 +1660,8 @@ zfs_acl_inherit(znode_t *zp, zfs_acl_t *paclp, uint64_t mode,
 	size_t		ace_size;
 	void		*data1, *data2;
 	size_t		data1sz, data2sz;
-	boolean_t	vdir = ZTOV(zp)->v_type == VDIR;
-	boolean_t	vreg = ZTOV(zp)->v_type == VREG;
+	boolean_t	vdir = vtype == VDIR;
+	boolean_t	vreg = vtype == VREG;
 	boolean_t	passthrough, passthrough_x, noallow;
 
 	passthrough_x =
@@ -1710,7 +1690,7 @@ zfs_acl_inherit(znode_t *zp, zfs_acl_t *paclp, uint64_t mode,
 
 		ace_size = aclp->z_ops.ace_size(pacep);
 
-		if (!zfs_ace_can_use(zp, iflags))
+		if (!zfs_ace_can_use(vtype, iflags))
 			continue;
 
 		/*
@@ -1806,55 +1786,58 @@ zfs_acl_inherit(znode_t *zp, zfs_acl_t *paclp, uint64_t mode,
  * Create file system object initial permissions
  * including inheritable ACEs.
  */
-void
-zfs_perm_init(znode_t *zp, znode_t *parent, int flag,
-    vattr_t *vap, dmu_tx_t *tx, cred_t *cr,
-    zfs_acl_t *setaclp, zfs_fuid_info_t **fuidp)
+int
+zfs_acl_ids_create(znode_t *dzp, int flag, vattr_t *vap, cred_t *cr,
+    vsecattr_t *vsecp, zfs_acl_ids_t *acl_ids)
 {
-	uint64_t	mode, fuid, fgid;
 	int		error;
-	zfsvfs_t	*zfsvfs = zp->z_zfsvfs;
-	zfs_acl_t	*aclp = NULL;
+	zfsvfs_t	*zfsvfs = dzp->z_zfsvfs;
 	zfs_acl_t	*paclp;
-	xvattr_t	*xvap = (xvattr_t *)vap;
 	gid_t		gid;
 	boolean_t	need_chmod = B_TRUE;
 
-	if (setaclp)
-		aclp = setaclp;
+	bzero(acl_ids, sizeof (zfs_acl_ids_t));
+	acl_ids->z_mode = MAKEIMODE(vap->va_type, vap->va_mode);
 
-	mode = MAKEIMODE(vap->va_type, vap->va_mode);
+	if (vsecp)
+		if ((error = zfs_vsec_2_aclp(zfsvfs, vap->va_type, vsecp, cr,
+		    &acl_ids->z_fuidp, &acl_ids->z_aclp)) != 0)
+			return (error);
 
 	/*
 	 * Determine uid and gid.
 	 */
 	if ((flag & (IS_ROOT_NODE | IS_REPLAY)) ||
 	    ((flag & IS_XATTR) && (vap->va_type == VDIR))) {
-		fuid = zfs_fuid_create(zfsvfs, vap->va_uid, cr,
-		    ZFS_OWNER, tx, fuidp);
-		fgid = zfs_fuid_create(zfsvfs, vap->va_gid, cr,
-		    ZFS_GROUP, tx, fuidp);
+		acl_ids->z_fuid = zfs_fuid_create(zfsvfs,
+		    (uint64_t)vap->va_uid, cr,
+		    ZFS_OWNER, &acl_ids->z_fuidp);
+		acl_ids->z_fgid = zfs_fuid_create(zfsvfs,
+		    (uint64_t)vap->va_gid, cr,
+		    ZFS_GROUP, &acl_ids->z_fuidp);
 		gid = vap->va_gid;
 	} else {
-		fuid = zfs_fuid_create_cred(zfsvfs, ZFS_OWNER, tx, cr, fuidp);
-		fgid = 0;
+		acl_ids->z_fuid = zfs_fuid_create_cred(zfsvfs, ZFS_OWNER,
+		    cr, &acl_ids->z_fuidp);
+		acl_ids->z_fgid = 0;
 		if (vap->va_mask & AT_GID)  {
-			fgid = zfs_fuid_create(zfsvfs, vap->va_gid, cr,
-			    ZFS_GROUP, tx, fuidp);
+			acl_ids->z_fgid = zfs_fuid_create(zfsvfs,
+			    (uint64_t)vap->va_gid,
+			    cr, ZFS_GROUP, &acl_ids->z_fuidp);
 			gid = vap->va_gid;
-			if (fgid != parent->z_phys->zp_gid &&
+			if (acl_ids->z_fgid != dzp->z_phys->zp_gid &&
 			    !groupmember(vap->va_gid, cr) &&
 			    secpolicy_vnode_create_gid(cr) != 0)
-				fgid = 0;
+				acl_ids->z_fgid = 0;
 		}
-		if (fgid == 0) {
-			if (parent->z_phys->zp_mode & S_ISGID) {
-				fgid = parent->z_phys->zp_gid;
-				gid = zfs_fuid_map_id(zfsvfs, fgid,
+		if (acl_ids->z_fgid == 0) {
+			if (dzp->z_phys->zp_mode & S_ISGID) {
+				acl_ids->z_fgid = dzp->z_phys->zp_gid;
+				gid = zfs_fuid_map_id(zfsvfs, acl_ids->z_fgid,
 				    cr, ZFS_GROUP);
 			} else {
-				fgid = zfs_fuid_create_cred(zfsvfs,
-				    ZFS_GROUP, tx, cr, fuidp);
+				acl_ids->z_fgid = zfs_fuid_create_cred(zfsvfs,
+				    ZFS_GROUP, cr, &acl_ids->z_fuidp);
 				gid = crgetgid(cr);
 			}
 		}
@@ -1867,57 +1850,61 @@ zfs_perm_init(znode_t *zp, znode_t *parent, int flag,
 	 * file's new group, clear the file's set-GID bit.
 	 */
 
-	if ((parent->z_phys->zp_mode & S_ISGID) && (vap->va_type == VDIR)) {
-		mode |= S_ISGID;
+	if (!(flag & IS_ROOT_NODE) && (dzp->z_phys->zp_mode & S_ISGID) &&
+	    (vap->va_type == VDIR)) {
+		acl_ids->z_mode |= S_ISGID;
 	} else {
-		if ((mode & S_ISGID) &&
+		if ((acl_ids->z_mode & S_ISGID) &&
 		    secpolicy_vnode_setids_setgids(cr, gid) != 0)
-			mode &= ~S_ISGID;
-	}
-
-	zp->z_phys->zp_uid = fuid;
-	zp->z_phys->zp_gid = fgid;
-	zp->z_phys->zp_mode = mode;
-
-	if (aclp == NULL) {
-		mutex_enter(&parent->z_lock);
-		if ((ZTOV(parent)->v_type == VDIR &&
-		    (parent->z_phys->zp_flags & ZFS_INHERIT_ACE)) &&
-		    !(zp->z_phys->zp_flags & ZFS_XATTR)) {
-			mutex_enter(&parent->z_acl_lock);
-			VERIFY(0 == zfs_acl_node_read(parent, &paclp, B_FALSE));
-			mutex_exit(&parent->z_acl_lock);
-			aclp = zfs_acl_inherit(zp, paclp, mode, &need_chmod);
+			acl_ids->z_mode &= ~S_ISGID;
+	}
+
+	if (acl_ids->z_aclp == NULL) {
+		mutex_enter(&dzp->z_lock);
+		if (!(flag & IS_ROOT_NODE) && (ZTOV(dzp)->v_type == VDIR &&
+		    (dzp->z_phys->zp_flags & ZFS_INHERIT_ACE)) &&
+		    !(dzp->z_phys->zp_flags & ZFS_XATTR)) {
+			mutex_enter(&dzp->z_acl_lock);
+			VERIFY(0 == zfs_acl_node_read(dzp, &paclp, B_FALSE));
+			mutex_exit(&dzp->z_acl_lock);
+			acl_ids->z_aclp = zfs_acl_inherit(zfsvfs,
+			    vap->va_type, paclp, acl_ids->z_mode, &need_chmod);
 			zfs_acl_free(paclp);
 		} else {
-			aclp = zfs_acl_alloc(zfs_acl_version_zp(zp));
+			acl_ids->z_aclp =
+			    zfs_acl_alloc(zfs_acl_version_zp(dzp));
+		}
+		mutex_exit(&dzp->z_lock);
+		if (need_chmod) {
+			acl_ids->z_aclp->z_hints = (vap->va_type == VDIR) ?
+			    ZFS_ACL_AUTO_INHERIT : 0;
+			zfs_acl_chmod(zfsvfs, acl_ids->z_fuid,
+			    acl_ids->z_mode, acl_ids->z_aclp);
 		}
-		mutex_exit(&parent->z_lock);
-		mutex_enter(&zp->z_lock);
-		mutex_enter(&zp->z_acl_lock);
-		if (need_chmod)
-			zfs_acl_chmod(zp, mode, aclp);
-	} else {
-		mutex_enter(&zp->z_lock);
-		mutex_enter(&zp->z_acl_lock);
 	}
 
-	/* Force auto_inherit on all new directory objects */
-	if (vap->va_type == VDIR)
-		aclp->z_hints |= ZFS_ACL_AUTO_INHERIT;
-
-	error = zfs_aclset_common(zp, aclp, cr, fuidp, tx);
-
-	/* Set optional attributes if any */
-	if (vap->va_mask & AT_XVATTR)
-		zfs_xvattr_set(zp, xvap);
+	return (0);
+}
 
-	mutex_exit(&zp->z_lock);
-	mutex_exit(&zp->z_acl_lock);
-	ASSERT3U(error, ==, 0);
+/*
+ * Free ACL and fuid_infop, but not the acl_ids structure
+ */
+void
+zfs_acl_ids_free(zfs_acl_ids_t *acl_ids)
+{
+	if (acl_ids->z_aclp)
+		zfs_acl_free(acl_ids->z_aclp);
+	if (acl_ids->z_fuidp)
+		zfs_fuid_info_free(acl_ids->z_fuidp);
+	acl_ids->z_aclp = NULL;
+	acl_ids->z_fuidp = NULL;
+}
 
-	if (aclp != setaclp)
-		zfs_acl_free(aclp);
+boolean_t
+zfs_acl_ids_overquota(zfsvfs_t *zfsvfs, zfs_acl_ids_t *acl_ids)
+{
+	return (zfs_usergroup_overquota(zfsvfs, B_FALSE, acl_ids->z_fuid) ||
+	    zfs_usergroup_overquota(zfsvfs, B_TRUE, acl_ids->z_fgid));
 }
 
 /*
@@ -2018,7 +2005,7 @@ zfs_getacl(znode_t *zp, vsecattr_t *vsecp, boolean_t skipaclchk, cred_t *cr)
 
 int
 zfs_vsec_2_aclp(zfsvfs_t *zfsvfs, vtype_t obj_type,
-    vsecattr_t *vsecp, zfs_acl_t **zaclp)
+    vsecattr_t *vsecp, cred_t *cr, zfs_fuid_info_t **fuidp, zfs_acl_t **zaclp)
 {
 	zfs_acl_t *aclp;
 	zfs_acl_node_t *aclnode;
@@ -2041,9 +2028,9 @@ zfs_vsec_2_aclp(zfsvfs_t *zfsvfs, vtype_t obj_type,
 			return (error);
 		}
 	} else {
-		if ((error = zfs_copy_ace_2_fuid(obj_type, aclp,
+		if ((error = zfs_copy_ace_2_fuid(zfsvfs, obj_type, aclp,
 		    vsecp->vsa_aclentp, aclnode->z_acldata, aclcnt,
-		    &aclnode->z_size)) != 0) {
+		    &aclnode->z_size, fuidp, cr)) != 0) {
 			zfs_acl_free(aclp);
 			zfs_acl_node_free(aclnode);
 			return (error);
@@ -2084,6 +2071,7 @@ zfs_setacl(znode_t *zp, vsecattr_t *vsecp, boolean_t skipaclchk, cred_t *cr)
 	int		error;
 	zfs_acl_t	*aclp;
 	zfs_fuid_info_t	*fuidp = NULL;
+	boolean_t	fuid_dirtied;
 
 	if (mask == 0)
 		return (ENOSYS);
@@ -2094,7 +2082,8 @@ zfs_setacl(znode_t *zp, vsecattr_t *vsecp, boolean_t skipaclchk, cred_t *cr)
 	if (error = zfs_zaccess(zp, ACE_WRITE_ACL, 0, skipaclchk, cr))
 		return (error);
 
-	error = zfs_vsec_2_aclp(zfsvfs, ZTOV(zp)->v_type, vsecp, &aclp);
+	error = zfs_vsec_2_aclp(zfsvfs, ZTOV(zp)->v_type, vsecp, cr, &fuidp,
+	    &aclp);
 	if (error)
 		return (error);
 
@@ -2135,18 +2124,9 @@ top:
 	} else if (aclp->z_acl_bytes > ZFS_ACE_SPACE) {
 		dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0, aclp->z_acl_bytes);
 	}
-	if (aclp->z_has_fuids) {
-		if (zfsvfs->z_fuid_obj == 0) {
-			dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
-			dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0,
-			    FUID_SIZE_ESTIMATE(zfsvfs));
-			dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, FALSE, NULL);
-		} else {
-			dmu_tx_hold_bonus(tx, zfsvfs->z_fuid_obj);
-			dmu_tx_hold_write(tx, zfsvfs->z_fuid_obj, 0,
-			    FUID_SIZE_ESTIMATE(zfsvfs));
-		}
-	}
+	fuid_dirtied = zfsvfs->z_fuid_dirty;
+	if (fuid_dirtied)
+		zfs_fuid_txhold(zfsvfs, tx);
 
 	error = dmu_tx_assign(tx, TXG_NOWAIT);
 	if (error) {
@@ -2163,9 +2143,13 @@ top:
 		return (error);
 	}
 
-	error = zfs_aclset_common(zp, aclp, cr, &fuidp, tx);
+	error = zfs_aclset_common(zp, aclp, cr, tx);
 	ASSERT(error == 0);
 
+	if (fuid_dirtied)
+		zfs_fuid_sync(zfsvfs, tx);
+
+	zfs_time_stamper_locked(zp, STATE_CHANGED, tx);
 	zfs_log_acl(zilog, tx, zp, vsecp, fuidp);
 
 	if (fuidp)
@@ -2180,45 +2164,17 @@ done:
 }
 
 /*
- * working_mode returns the permissions that were not granted
+ * Check accesses of interest (AoI) against attributes of the dataset
+ * such as read-only.  Returns zero if no AoI conflict with dataset
+ * attributes, otherwise an appropriate errno is returned.
  */
 static int
-zfs_zaccess_common(znode_t *zp, uint32_t v4_mode, uint32_t *working_mode,
-    boolean_t *check_privs, boolean_t skipaclchk, cred_t *cr)
+zfs_zaccess_dataset_check(znode_t *zp, uint32_t v4_mode)
 {
-	zfs_acl_t	*aclp;
-	zfsvfs_t	*zfsvfs = zp->z_zfsvfs;
-	int		error;
-	uid_t		uid = crgetuid(cr);
-	uint64_t 	who;
-	uint16_t	type, iflags;
-	uint16_t	entry_type;
-	uint32_t	access_mask;
-	uint32_t	deny_mask = 0;
-	zfs_ace_hdr_t	*acep = NULL;
-	boolean_t	checkit;
-	uid_t		fowner;
-	uid_t		gowner;
-
-	/*
-	 * Short circuit empty requests
-	 */
-	if (v4_mode == 0)
-		return (0);
-
-	*check_privs = B_TRUE;
-
-	if (zfsvfs->z_replay) {
-		*working_mode = 0;
-		return (0);
-	}
-
-	*working_mode = v4_mode;
-
 	if ((v4_mode & WRITE_MASK) &&
 	    (zp->z_zfsvfs->z_vfs->vfs_flag & VFS_RDONLY) &&
-	    (!IS_DEVVP(ZTOV(zp)))) {
-		*check_privs = B_FALSE;
+	    (!IS_DEVVP(ZTOV(zp)) ||
+	    (IS_DEVVP(ZTOV(zp)) && (v4_mode & WRITE_MASK_ATTRS)))) {
 		return (EROFS);
 	}
 
@@ -2230,31 +2186,64 @@ zfs_zaccess_common(znode_t *zp, uint32_t v4_mode, uint32_t *working_mode,
 	    (zp->z_phys->zp_flags & (ZFS_READONLY | ZFS_IMMUTABLE))) ||
 	    (ZTOV(zp)->v_type == VDIR &&
 	    (zp->z_phys->zp_flags & ZFS_IMMUTABLE)))) {
-		*check_privs = B_FALSE;
 		return (EPERM);
 	}
 
 	if ((v4_mode & (ACE_DELETE | ACE_DELETE_CHILD)) &&
 	    (zp->z_phys->zp_flags & ZFS_NOUNLINK)) {
-		*check_privs = B_FALSE;
 		return (EPERM);
 	}
 
 	if (((v4_mode & (ACE_READ_DATA|ACE_EXECUTE)) &&
 	    (zp->z_phys->zp_flags & ZFS_AV_QUARANTINED))) {
-		*check_privs = B_FALSE;
 		return (EACCES);
 	}
 
-	/*
-	 * The caller requested that the ACL check be skipped.  This
-	 * would only happen if the caller checked VOP_ACCESS() with a
-	 * 32 bit ACE mask and already had the appropriate permissions.
-	 */
-	if (skipaclchk) {
-		*working_mode = 0;
-		return (0);
-	}
+	return (0);
+}
+
+/*
+ * The primary usage of this function is to loop through all of the
+ * ACEs in the znode, determining what accesses of interest (AoI) to
+ * the caller are allowed or denied.  The AoI are expressed as bits in
+ * the working_mode parameter.  As each ACE is processed, bits covered
+ * by that ACE are removed from the working_mode.  This removal
+ * facilitates two things.  The first is that when the working mode is
+ * empty (= 0), we know we've looked at all the AoI. The second is
+ * that the ACE interpretation rules don't allow a later ACE to undo
+ * something granted or denied by an earlier ACE.  Removing the
+ * discovered access or denial enforces this rule.  At the end of
+ * processing the ACEs, all AoI that were found to be denied are
+ * placed into the working_mode, giving the caller a mask of denied
+ * accesses.  Returns:
+ *	0		if all AoI granted
+ *	EACCESS 	if the denied mask is non-zero
+ *	other error	if abnormal failure (e.g., IO error)
+ *
+ * A secondary usage of the function is to determine if any of the
+ * AoI are granted.  If an ACE grants any access in
+ * the working_mode, we immediately short circuit out of the function.
+ * This mode is chosen by setting anyaccess to B_TRUE.  The
+ * working_mode is not a denied access mask upon exit if the function
+ * is used in this manner.
+ */
+static int
+zfs_zaccess_aces_check(znode_t *zp, uint32_t *working_mode,
+    boolean_t anyaccess, cred_t *cr)
+{
+	zfsvfs_t	*zfsvfs = zp->z_zfsvfs;
+	zfs_acl_t	*aclp;
+	int		error;
+	uid_t		uid = crgetuid(cr);
+	uint64_t 	who;
+	uint16_t	type, iflags;
+	uint16_t	entry_type;
+	uint32_t	access_mask;
+	uint32_t	deny_mask = 0;
+	zfs_ace_hdr_t	*acep = NULL;
+	boolean_t	checkit;
+	uid_t		fowner;
+	uid_t		gowner;
 
 	zfs_fuid_map_ids(zp, cr, &fowner, &gowner);
 
@@ -2268,6 +2257,7 @@ zfs_zaccess_common(znode_t *zp, uint32_t v4_mode, uint32_t *working_mode,
 
 	while (acep = zfs_acl_next_ace(aclp, acep, &who, &access_mask,
 	    &iflags, &type)) {
+		uint32_t mask_matched;
 
 		if (!zfs_acl_valid_ace_type(type, iflags))
 			continue;
@@ -2275,6 +2265,11 @@ zfs_zaccess_common(znode_t *zp, uint32_t v4_mode, uint32_t *working_mode,
 		if (ZTOV(zp)->v_type == VDIR && (iflags & ACE_INHERIT_ONLY_ACE))
 			continue;
 
+		/* Skip ACE if it does not affect any AoI */
+		mask_matched = (access_mask & *working_mode);
+		if (!mask_matched)
+			continue;
+
 		entry_type = (iflags & ACE_TYPE_FLAGS);
 
 		checkit = B_FALSE;
@@ -2313,14 +2308,24 @@ zfs_zaccess_common(znode_t *zp, uint32_t v4_mode, uint32_t *working_mode,
 		}
 
 		if (checkit) {
-			uint32_t mask_matched = (access_mask & *working_mode);
-
-			if (mask_matched) {
-				if (type == DENY)
-					deny_mask |= mask_matched;
-
-				*working_mode &= ~mask_matched;
+			if (type == DENY) {
+				DTRACE_PROBE3(zfs__ace__denies,
+				    znode_t *, zp,
+				    zfs_ace_hdr_t *, acep,
+				    uint32_t, mask_matched);
+				deny_mask |= mask_matched;
+			} else {
+				DTRACE_PROBE3(zfs__ace__allows,
+				    znode_t *, zp,
+				    zfs_ace_hdr_t *, acep,
+				    uint32_t, mask_matched);
+				if (anyaccess) {
+					mutex_exit(&zp->z_acl_lock);
+					zfs_acl_free(aclp);
+					return (0);
+				}
 			}
+			*working_mode &= ~mask_matched;
 		}
 
 		/* Are we done? */
@@ -2342,6 +2347,69 @@ zfs_zaccess_common(znode_t *zp, uint32_t v4_mode, uint32_t *working_mode,
 	return (0);
 }
 
+/*
+ * Return true if any access whatsoever granted, we don't actually
+ * care what access is granted.
+ */
+boolean_t
+zfs_has_access(znode_t *zp, cred_t *cr)
+{
+	uint32_t have = ACE_ALL_PERMS;
+
+	if (zfs_zaccess_aces_check(zp, &have, B_TRUE, cr) != 0) {
+		uid_t		owner;
+
+		owner = zfs_fuid_map_id(zp->z_zfsvfs,
+		    zp->z_phys->zp_uid, cr, ZFS_OWNER);
+
+		return (
+		    secpolicy_vnode_access(cr, ZTOV(zp), owner, VREAD) == 0 ||
+		    secpolicy_vnode_access(cr, ZTOV(zp), owner, VWRITE) == 0 ||
+		    secpolicy_vnode_access(cr, ZTOV(zp), owner, VEXEC) == 0 ||
+		    secpolicy_vnode_chown(cr, B_TRUE) == 0 ||
+		    secpolicy_vnode_chown(cr, B_FALSE) == 0 ||
+		    secpolicy_vnode_setdac(cr, owner) == 0 ||
+		    secpolicy_vnode_remove(cr) == 0);
+	}
+	return (B_TRUE);
+}
+
+static int
+zfs_zaccess_common(znode_t *zp, uint32_t v4_mode, uint32_t *working_mode,
+    boolean_t *check_privs, boolean_t skipaclchk, cred_t *cr)
+{
+	zfsvfs_t *zfsvfs = zp->z_zfsvfs;
+	int err;
+
+	*working_mode = v4_mode;
+	*check_privs = B_TRUE;
+
+	/*
+	 * Short circuit empty requests
+	 */
+	if (v4_mode == 0 || zfsvfs->z_replay) {
+		*working_mode = 0;
+		return (0);
+	}
+
+	if ((err = zfs_zaccess_dataset_check(zp, v4_mode)) != 0) {
+		*check_privs = B_FALSE;
+		return (err);
+	}
+
+	/*
+	 * The caller requested that the ACL check be skipped.  This
+	 * would only happen if the caller checked VOP_ACCESS() with a
+	 * 32 bit ACE mask and already had the appropriate permissions.
+	 */
+	if (skipaclchk) {
+		*working_mode = 0;
+		return (0);
+	}
+
+	return (zfs_zaccess_aces_check(zp, working_mode, B_FALSE, cr));
+}
+
 static int
 zfs_zaccess_append(znode_t *zp, uint32_t *working_mode, boolean_t *check_privs,
     cred_t *cr)
diff --git a/module/zfs/zfs_ctldir.c b/module/zfs/zfs_ctldir.c
index 0da026100..27c2c51a3 100644
--- a/module/zfs/zfs_ctldir.c
+++ b/module/zfs/zfs_ctldir.c
@@ -114,12 +114,16 @@ snapentry_compare(const void *a, const void *b)
 vnodeops_t *zfsctl_ops_root;
 vnodeops_t *zfsctl_ops_snapdir;
 vnodeops_t *zfsctl_ops_snapshot;
+vnodeops_t *zfsctl_ops_shares;
+vnodeops_t *zfsctl_ops_shares_dir;
 
 static const fs_operation_def_t zfsctl_tops_root[];
 static const fs_operation_def_t zfsctl_tops_snapdir[];
 static const fs_operation_def_t zfsctl_tops_snapshot[];
+static const fs_operation_def_t zfsctl_tops_shares[];
 
 static vnode_t *zfsctl_mknode_snapdir(vnode_t *);
+static vnode_t *zfsctl_mknode_shares(vnode_t *);
 static vnode_t *zfsctl_snapshot_mknode(vnode_t *, uint64_t objset);
 static int zfsctl_unmount_snap(zfs_snapentry_t *, int, cred_t *);
 
@@ -127,14 +131,18 @@ static gfs_opsvec_t zfsctl_opsvec[] = {
 	{ ".zfs", zfsctl_tops_root, &zfsctl_ops_root },
 	{ ".zfs/snapshot", zfsctl_tops_snapdir, &zfsctl_ops_snapdir },
 	{ ".zfs/snapshot/vnode", zfsctl_tops_snapshot, &zfsctl_ops_snapshot },
+	{ ".zfs/shares", zfsctl_tops_shares, &zfsctl_ops_shares_dir },
+	{ ".zfs/shares/vnode", zfsctl_tops_shares, &zfsctl_ops_shares },
 	{ NULL }
 };
 
 /*
- * Root directory elements.  We have only a single static entry, 'snapshot'.
+ * Root directory elements.  We only have two entries
+ * snapshot and shares.
  */
 static gfs_dirent_t zfsctl_root_entries[] = {
 	{ "snapshot", zfsctl_mknode_snapdir, GFS_CACHE_VNODE },
+	{ "shares", zfsctl_mknode_shares, GFS_CACHE_VNODE },
 	{ NULL }
 };
 
@@ -166,21 +174,34 @@ zfsctl_fini(void)
 		vn_freevnodeops(zfsctl_ops_snapdir);
 	if (zfsctl_ops_snapshot)
 		vn_freevnodeops(zfsctl_ops_snapshot);
+	if (zfsctl_ops_shares)
+		vn_freevnodeops(zfsctl_ops_shares);
+	if (zfsctl_ops_shares_dir)
+		vn_freevnodeops(zfsctl_ops_shares_dir);
 
 	zfsctl_ops_root = NULL;
 	zfsctl_ops_snapdir = NULL;
 	zfsctl_ops_snapshot = NULL;
+	zfsctl_ops_shares = NULL;
+	zfsctl_ops_shares_dir = NULL;
 }
 
 /*
- * Return the inode number associated with the 'snapshot' directory.
+ * Return the inode number associated with the 'snapshot' or
+ * 'shares' directory.
  */
 /* ARGSUSED */
 static ino64_t
 zfsctl_root_inode_cb(vnode_t *vp, int index)
 {
-	ASSERT(index == 0);
-	return (ZFSCTL_INO_SNAPDIR);
+	zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
+
+	ASSERT(index <= 2);
+
+	if (index == 0)
+		return (ZFSCTL_INO_SNAPDIR);
+
+	return (zfsvfs->z_shares_dir);
 }
 
 /*
@@ -348,6 +369,30 @@ zfsctl_common_fid(vnode_t *vp, fid_t *fidp, caller_context_t *ct)
 	return (0);
 }
 
+
+/*ARGSUSED*/
+static int
+zfsctl_shares_fid(vnode_t *vp, fid_t *fidp, caller_context_t *ct)
+{
+	zfsvfs_t	*zfsvfs = vp->v_vfsp->vfs_data;
+	znode_t		*dzp;
+	int		error;
+
+	ZFS_ENTER(zfsvfs);
+
+	if (zfsvfs->z_shares_dir == 0) {
+		ZFS_EXIT(zfsvfs);
+		return (ENOTSUP);
+	}
+
+	if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) {
+		error = VOP_FID(ZTOV(dzp), fidp, ct);
+		VN_RELE(ZTOV(dzp));
+	}
+
+	ZFS_EXIT(zfsvfs);
+	return (error);
+}
 /*
  * .zfs inode namespace
  *
@@ -478,7 +523,7 @@ zfsctl_unmount_snap(zfs_snapentry_t *sep, int fflags, cred_t *cr)
 		VN_RELE(svp);
 		return (error);
 	}
-	VFS_RELE(svp->v_vfsp);
+
 	/*
 	 * We can't use VN_RELE(), as that will try to invoke
 	 * zfsctl_snapdir_inactive(), which would cause us to destroy
@@ -691,7 +736,7 @@ zfsctl_snapdir_mkdir(vnode_t *dvp, char *dirname, vattr_t *vap, vnode_t  **vpp,
 		return (err);
 
 	if (err == 0) {
-		err = dmu_objset_snapshot(name, dirname, B_FALSE);
+		err = dmu_objset_snapshot(name, dirname, NULL, B_FALSE);
 		if (err)
 			return (err);
 		err = lookupnameat(dirname, seg, follow, NULL, vpp, dvp);
@@ -732,9 +777,6 @@ zfsctl_snapdir_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, pathname_t *pnp,
 
 	ASSERT(dvp->v_type == VDIR);
 
-	if (gfs_lookup_dot(vpp, dvp, zfsvfs->z_ctldir, nm) == 0)
-		return (0);
-
 	/*
 	 * If we get a recursive call, that means we got called
 	 * from the domount() code while it was trying to look up the
@@ -746,6 +788,11 @@ zfsctl_snapdir_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, pathname_t *pnp,
 
 	ZFS_ENTER(zfsvfs);
 
+	if (gfs_lookup_dot(vpp, dvp, zfsvfs->z_ctldir, nm) == 0) {
+		ZFS_EXIT(zfsvfs);
+		return (0);
+	}
+
 	if (flags & FIGNORECASE) {
 		boolean_t conflict = B_FALSE;
 
@@ -844,7 +891,7 @@ domount:
 		 * Return the mounted root rather than the covered mount point.
 		 * Takes the GFS vnode at .zfs/snapshot/<snapname> and returns
 		 * the ZFS vnode mounted on top of the GFS node.  This ZFS
-		 * vnode is the root the newly created vfsp.
+		 * vnode is the root of the newly created vfsp.
 		 */
 		VFS_RELE(vfsp);
 		err = traverse(vpp);
@@ -879,6 +926,37 @@ domount:
 
 /* ARGSUSED */
 static int
+zfsctl_shares_lookup(vnode_t *dvp, char *nm, vnode_t **vpp, pathname_t *pnp,
+    int flags, vnode_t *rdir, cred_t *cr, caller_context_t *ct,
+    int *direntflags, pathname_t *realpnp)
+{
+	zfsvfs_t *zfsvfs = dvp->v_vfsp->vfs_data;
+	znode_t *dzp;
+	int error;
+
+	ZFS_ENTER(zfsvfs);
+
+	if (gfs_lookup_dot(vpp, dvp, zfsvfs->z_ctldir, nm) == 0) {
+		ZFS_EXIT(zfsvfs);
+		return (0);
+	}
+
+	if (zfsvfs->z_shares_dir == 0) {
+		ZFS_EXIT(zfsvfs);
+		return (ENOTSUP);
+	}
+	if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0)
+		error = VOP_LOOKUP(ZTOV(dzp), nm, vpp, pnp,
+		    flags, rdir, cr, ct, direntflags, realpnp);
+
+	VN_RELE(ZTOV(dzp));
+	ZFS_EXIT(zfsvfs);
+
+	return (error);
+}
+
+/* ARGSUSED */
+static int
 zfsctl_snapdir_readdir_cb(vnode_t *vp, void *dp, int *eofp,
     offset_t *offp, offset_t *nextp, void *data, int flags)
 {
@@ -921,6 +999,33 @@ zfsctl_snapdir_readdir_cb(vnode_t *vp, void *dp, int *eofp,
 	return (0);
 }
 
+/* ARGSUSED */
+static int
+zfsctl_shares_readdir(vnode_t *vp, uio_t *uiop, cred_t *cr, int *eofp,
+    caller_context_t *ct, int flags)
+{
+	zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
+	znode_t *dzp;
+	int error;
+
+	ZFS_ENTER(zfsvfs);
+
+	if (zfsvfs->z_shares_dir == 0) {
+		ZFS_EXIT(zfsvfs);
+		return (ENOTSUP);
+	}
+	if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) {
+		error = VOP_READDIR(ZTOV(dzp), uiop, cr, eofp, ct, flags);
+		VN_RELE(ZTOV(dzp));
+	} else {
+		*eofp = 1;
+		error = ENOENT;
+	}
+
+	ZFS_EXIT(zfsvfs);
+	return (error);
+}
+
 /*
  * pvp is the '.zfs' directory (zfsctl_node_t).
  * Creates vp, which is '.zfs/snapshot' (zfsctl_snapdir_t).
@@ -946,6 +1051,45 @@ zfsctl_mknode_snapdir(vnode_t *pvp)
 	return (vp);
 }
 
+vnode_t *
+zfsctl_mknode_shares(vnode_t *pvp)
+{
+	vnode_t *vp;
+	zfsctl_node_t *sdp;
+
+	vp = gfs_dir_create(sizeof (zfsctl_node_t), pvp,
+	    zfsctl_ops_shares, NULL, NULL, MAXNAMELEN,
+	    NULL, NULL);
+	sdp = vp->v_data;
+	sdp->zc_cmtime = ((zfsctl_node_t *)pvp->v_data)->zc_cmtime;
+	return (vp);
+
+}
+
+/* ARGSUSED */
+static int
+zfsctl_shares_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
+    caller_context_t *ct)
+{
+	zfsvfs_t *zfsvfs = vp->v_vfsp->vfs_data;
+	znode_t *dzp;
+	int error;
+
+	ZFS_ENTER(zfsvfs);
+	if (zfsvfs->z_shares_dir == 0) {
+		ZFS_EXIT(zfsvfs);
+		return (ENOTSUP);
+	}
+	if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &dzp)) == 0) {
+		error = VOP_GETATTR(ZTOV(dzp), vap, flags, cr, ct);
+		VN_RELE(ZTOV(dzp));
+	}
+	ZFS_EXIT(zfsvfs);
+	return (error);
+
+
+}
+
 /* ARGSUSED */
 static int
 zfsctl_snapdir_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
@@ -996,6 +1140,20 @@ static const fs_operation_def_t zfsctl_tops_snapdir[] = {
 	{ NULL }
 };
 
+static const fs_operation_def_t zfsctl_tops_shares[] = {
+	{ VOPNAME_OPEN,		{ .vop_open = zfsctl_common_open }	},
+	{ VOPNAME_CLOSE,	{ .vop_close = zfsctl_common_close }	},
+	{ VOPNAME_IOCTL,	{ .error = fs_inval }			},
+	{ VOPNAME_GETATTR,	{ .vop_getattr = zfsctl_shares_getattr } },
+	{ VOPNAME_ACCESS,	{ .vop_access = zfsctl_common_access }	},
+	{ VOPNAME_READDIR,	{ .vop_readdir = zfsctl_shares_readdir } },
+	{ VOPNAME_LOOKUP,	{ .vop_lookup = zfsctl_shares_lookup }	},
+	{ VOPNAME_SEEK,		{ .vop_seek = fs_seek }			},
+	{ VOPNAME_INACTIVE,	{ .vop_inactive = gfs_vop_inactive } },
+	{ VOPNAME_FID,		{ .vop_fid = zfsctl_shares_fid } },
+	{ NULL }
+};
+
 /*
  * pvp is the GFS vnode '.zfs/snapshot'.
  *
@@ -1013,7 +1171,6 @@ zfsctl_snapshot_mknode(vnode_t *pvp, uint64_t objset)
 	    zfsctl_ops_snapshot, NULL, NULL, MAXNAMELEN, NULL, NULL);
 	zcp = vp->v_data;
 	zcp->zc_id = objset;
-	VFS_HOLD(vp->v_vfsp);
 
 	return (vp);
 }
@@ -1052,7 +1209,6 @@ zfsctl_snapshot_inactive(vnode_t *vp, cred_t *cr, caller_context_t *ct)
 
 	mutex_exit(&sdp->sd_lock);
 	VN_RELE(dvp);
-	VFS_RELE(vp->v_vfsp);
 
 	/*
 	 * Dispose of the vnode for the snapshot mount point.
diff --git a/module/zfs/zfs_dir.c b/module/zfs/zfs_dir.c
index 9353d0199..b3f768328 100644
--- a/module/zfs/zfs_dir.c
+++ b/module/zfs/zfs_dir.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -805,44 +805,49 @@ zfs_make_xattrdir(znode_t *zp, vattr_t *vap, vnode_t **xvpp, cred_t *cr)
 	znode_t *xzp;
 	dmu_tx_t *tx;
 	int error;
-	zfs_fuid_info_t *fuidp = NULL;
+	zfs_acl_ids_t acl_ids;
+	boolean_t fuid_dirtied;
 
 	*xvpp = NULL;
 
 	if (error = zfs_zaccess(zp, ACE_WRITE_NAMED_ATTRS, 0, B_FALSE, cr))
 		return (error);
 
+	if ((error = zfs_acl_ids_create(zp, IS_XATTR, vap, cr, NULL,
+	    &acl_ids)) != 0)
+		return (error);
+	if (zfs_acl_ids_overquota(zfsvfs, &acl_ids)) {
+		zfs_acl_ids_free(&acl_ids);
+		return (EDQUOT);
+	}
+
 	tx = dmu_tx_create(zfsvfs->z_os);
 	dmu_tx_hold_bonus(tx, zp->z_id);
 	dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, FALSE, NULL);
-	if (IS_EPHEMERAL(crgetuid(cr)) || IS_EPHEMERAL(crgetgid(cr))) {
-		if (zfsvfs->z_fuid_obj == 0) {
-			dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
-			dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0,
-			    FUID_SIZE_ESTIMATE(zfsvfs));
-			dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, FALSE, NULL);
-		} else {
-			dmu_tx_hold_bonus(tx, zfsvfs->z_fuid_obj);
-			dmu_tx_hold_write(tx, zfsvfs->z_fuid_obj, 0,
-			    FUID_SIZE_ESTIMATE(zfsvfs));
-		}
-	}
+	fuid_dirtied = zfsvfs->z_fuid_dirty;
+	if (fuid_dirtied)
+		zfs_fuid_txhold(zfsvfs, tx);
 	error = dmu_tx_assign(tx, TXG_NOWAIT);
 	if (error) {
+		zfs_acl_ids_free(&acl_ids);
 		if (error == ERESTART)
 			dmu_tx_wait(tx);
 		dmu_tx_abort(tx);
 		return (error);
 	}
-	zfs_mknode(zp, vap, tx, cr, IS_XATTR, &xzp, 0, NULL, &fuidp);
+	zfs_mknode(zp, vap, tx, cr, IS_XATTR, &xzp, 0, &acl_ids);
+
+	if (fuid_dirtied)
+		zfs_fuid_sync(zfsvfs, tx);
+
 	ASSERT(xzp->z_phys->zp_parent == zp->z_id);
 	dmu_buf_will_dirty(zp->z_dbuf, tx);
 	zp->z_phys->zp_xattr = xzp->z_id;
 
 	(void) zfs_log_create(zfsvfs->z_log, tx, TX_MKXATTR, zp,
-	    xzp, "", NULL, fuidp, vap);
-	if (fuidp)
-		zfs_fuid_info_free(fuidp);
+	    xzp, "", NULL, acl_ids.z_fuidp, vap);
+
+	zfs_acl_ids_free(&acl_ids);
 	dmu_tx_commit(tx);
 
 	*xvpp = ZTOV(xzp);
diff --git a/module/zfs/zfs_fm.c b/module/zfs/zfs_fm.c
index 236d69e7e..8b7785fa8 100644
--- a/module/zfs/zfs_fm.c
+++ b/module/zfs/zfs_fm.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -96,7 +96,6 @@ zfs_ereport_post(const char *subclass, spa_t *spa, vdev_t *vd, zio_t *zio,
 	nvlist_t *ereport, *detector;
 	uint64_t ena;
 	char class[64];
-	int state;
 
 	/*
 	 * If we are doing a spa_tryimport(), ignore errors.
@@ -130,15 +129,39 @@ zfs_ereport_post(const char *subclass, spa_t *spa, vdev_t *vd, zio_t *zio,
 			return;
 
 		/*
-		 * If the vdev has already been marked as failing due to a
-		 * failed probe, then ignore any subsequent I/O errors, as the
-		 * DE will automatically fault the vdev on the first such
-		 * failure.
+		 * If this I/O is not a retry I/O, don't post an ereport.
+		 * Otherwise, we risk making bad diagnoses based on B_FAILFAST
+		 * I/Os.
 		 */
-		if (vd != NULL &&
-		    (!vdev_readable(vd) || !vdev_writeable(vd)) &&
-		    strcmp(subclass, FM_EREPORT_ZFS_PROBE_FAILURE) != 0)
+		if (zio->io_error == EIO &&
+		    !(zio->io_flags & ZIO_FLAG_IO_RETRY))
 			return;
+
+		if (vd != NULL) {
+			/*
+			 * If the vdev has already been marked as failing due
+			 * to a failed probe, then ignore any subsequent I/O
+			 * errors, as the DE will automatically fault the vdev
+			 * on the first such failure.  This also catches cases
+			 * where vdev_remove_wanted is set and the device has
+			 * not yet been asynchronously placed into the REMOVED
+			 * state.
+			 */
+			if (zio->io_vd == vd &&
+			    !vdev_accessible(vd, zio) &&
+			    strcmp(subclass, FM_EREPORT_ZFS_PROBE_FAILURE) != 0)
+				return;
+
+			/*
+			 * Ignore checksum errors for reads from DTL regions of
+			 * leaf vdevs.
+			 */
+			if (zio->io_type == ZIO_TYPE_READ &&
+			    zio->io_error == ECKSUM &&
+			    vd->vdev_ops->vdev_op_leaf &&
+			    vdev_dtl_contains(vd, DTL_MISSING, zio->io_txg, 1))
+				return;
+		}
 	}
 
 	if ((ereport = fm_nvlist_create(NULL)) == NULL)
@@ -189,21 +212,13 @@ zfs_ereport_post(const char *subclass, spa_t *spa, vdev_t *vd, zio_t *zio,
 	 */
 
 	/*
-	 * If we are importing a faulted pool, then we treat it like an open,
-	 * not an import.  Otherwise, the DE will ignore all faults during
-	 * import, since the default behavior is to mark the devices as
-	 * persistently unavailable, not leave them in the faulted state.
-	 */
-	state = spa->spa_import_faulted ? SPA_LOAD_OPEN : spa->spa_load_state;
-
-	/*
 	 * Generic payload members common to all ereports.
 	 */
 	fm_payload_set(ereport, FM_EREPORT_PAYLOAD_ZFS_POOL,
 	    DATA_TYPE_STRING, spa_name(spa), FM_EREPORT_PAYLOAD_ZFS_POOL_GUID,
 	    DATA_TYPE_UINT64, spa_guid(spa),
 	    FM_EREPORT_PAYLOAD_ZFS_POOL_CONTEXT, DATA_TYPE_INT32,
-	    state, NULL);
+	    spa->spa_load_state, NULL);
 
 	if (spa != NULL) {
 		fm_payload_set(ereport, FM_EREPORT_PAYLOAD_ZFS_POOL_FAILMODE,
@@ -222,14 +237,18 @@ zfs_ereport_post(const char *subclass, spa_t *spa, vdev_t *vd, zio_t *zio,
 		    DATA_TYPE_UINT64, vd->vdev_guid,
 		    FM_EREPORT_PAYLOAD_ZFS_VDEV_TYPE,
 		    DATA_TYPE_STRING, vd->vdev_ops->vdev_op_type, NULL);
-		if (vd->vdev_path)
+		if (vd->vdev_path != NULL)
 			fm_payload_set(ereport,
 			    FM_EREPORT_PAYLOAD_ZFS_VDEV_PATH,
 			    DATA_TYPE_STRING, vd->vdev_path, NULL);
-		if (vd->vdev_devid)
+		if (vd->vdev_devid != NULL)
 			fm_payload_set(ereport,
 			    FM_EREPORT_PAYLOAD_ZFS_VDEV_DEVID,
 			    DATA_TYPE_STRING, vd->vdev_devid, NULL);
+		if (vd->vdev_fru != NULL)
+			fm_payload_set(ereport,
+			    FM_EREPORT_PAYLOAD_ZFS_VDEV_FRU,
+			    DATA_TYPE_STRING, vd->vdev_fru, NULL);
 
 		if (pvd != NULL) {
 			fm_payload_set(ereport,
diff --git a/module/zfs/zfs_fuid.c b/module/zfs/zfs_fuid.c
index 286dafba8..8e481dffb 100644
--- a/module/zfs/zfs_fuid.c
+++ b/module/zfs/zfs_fuid.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -47,8 +47,10 @@
  * During file system initialization the nvlist(s) are read and
  * two AVL trees are created.  One tree is keyed by the index number
  * and the other by the domain string.  Nodes are never removed from
- * trees, but new entries may be added.  If a new entry is added then the
- * on-disk packed nvlist will also be updated.
+ * trees, but new entries may be added.  If a new entry is added then
+ * the zfsvfs->z_fuid_dirty flag is set to true and the caller will then
+ * be responsible for calling zfs_fuid_sync() to sync the changes to disk.
+ *
  */
 
 #define	FUID_IDX	"fuid_idx"
@@ -97,6 +99,15 @@ domain_compare(const void *arg1, const void *arg2)
 	return (val > 0 ? 1 : -1);
 }
 
+void
+zfs_fuid_avl_tree_create(avl_tree_t *idx_tree, avl_tree_t *domain_tree)
+{
+	avl_create(idx_tree, idx_compare,
+	    sizeof (fuid_domain_t), offsetof(fuid_domain_t, f_idxnode));
+	avl_create(domain_tree, domain_compare,
+	    sizeof (fuid_domain_t), offsetof(fuid_domain_t, f_domnode));
+}
+
 /*
  * load initial fuid domain and idx trees.  This function is used by
  * both the kernel and zdb.
@@ -108,12 +119,9 @@ zfs_fuid_table_load(objset_t *os, uint64_t fuid_obj, avl_tree_t *idx_tree,
 	dmu_buf_t *db;
 	uint64_t fuid_size;
 
-	avl_create(idx_tree, idx_compare,
-	    sizeof (fuid_domain_t), offsetof(fuid_domain_t, f_idxnode));
-	avl_create(domain_tree, domain_compare,
-	    sizeof (fuid_domain_t), offsetof(fuid_domain_t, f_domnode));
-
-	VERIFY(0 == dmu_bonus_hold(os, fuid_obj, FTAG, &db));
+	ASSERT(fuid_obj != 0);
+	VERIFY(0 == dmu_bonus_hold(os, fuid_obj,
+	    FTAG, &db));
 	fuid_size = *(uint64_t *)db->db_data;
 	dmu_buf_rele(db, FTAG);
 
@@ -125,7 +133,8 @@ zfs_fuid_table_load(objset_t *os, uint64_t fuid_obj, avl_tree_t *idx_tree,
 		int i;
 
 		packed = kmem_alloc(fuid_size, KM_SLEEP);
-		VERIFY(dmu_read(os, fuid_obj, 0, fuid_size, packed) == 0);
+		VERIFY(dmu_read(os, fuid_obj, 0,
+		    fuid_size, packed, DMU_READ_PREFETCH) == 0);
 		VERIFY(nvlist_unpack(packed, fuid_size,
 		    &nvp, 0) == 0);
 		VERIFY(nvlist_lookup_nvlist_array(nvp, FUID_NVP_ARRAY,
@@ -189,10 +198,8 @@ zfs_fuid_idx_domain(avl_tree_t *idx_tree, uint32_t idx)
  * Load the fuid table(s) into memory.
  */
 static void
-zfs_fuid_init(zfsvfs_t *zfsvfs, dmu_tx_t *tx)
+zfs_fuid_init(zfsvfs_t *zfsvfs)
 {
-	int error = 0;
-
 	rw_enter(&zfsvfs->z_fuid_lock, RW_WRITER);
 
 	if (zfsvfs->z_fuid_loaded) {
@@ -200,41 +207,101 @@ zfs_fuid_init(zfsvfs_t *zfsvfs, dmu_tx_t *tx)
 		return;
 	}
 
-	if (zfsvfs->z_fuid_obj == 0) {
-
-		/* first make sure we need to allocate object */
-
-		error = zap_lookup(zfsvfs->z_os, MASTER_NODE_OBJ,
-		    ZFS_FUID_TABLES, 8, 1, &zfsvfs->z_fuid_obj);
-		if (error == ENOENT && tx != NULL) {
-			zfsvfs->z_fuid_obj = dmu_object_alloc(zfsvfs->z_os,
-			    DMU_OT_FUID, 1 << 14, DMU_OT_FUID_SIZE,
-			    sizeof (uint64_t), tx);
-			VERIFY(zap_add(zfsvfs->z_os, MASTER_NODE_OBJ,
-			    ZFS_FUID_TABLES, sizeof (uint64_t), 1,
-			    &zfsvfs->z_fuid_obj, tx) == 0);
-		}
-	}
+	zfs_fuid_avl_tree_create(&zfsvfs->z_fuid_idx, &zfsvfs->z_fuid_domain);
 
+	(void) zap_lookup(zfsvfs->z_os, MASTER_NODE_OBJ,
+	    ZFS_FUID_TABLES, 8, 1, &zfsvfs->z_fuid_obj);
 	if (zfsvfs->z_fuid_obj != 0) {
 		zfsvfs->z_fuid_size = zfs_fuid_table_load(zfsvfs->z_os,
 		    zfsvfs->z_fuid_obj, &zfsvfs->z_fuid_idx,
 		    &zfsvfs->z_fuid_domain);
-		zfsvfs->z_fuid_loaded = B_TRUE;
 	}
 
+	zfsvfs->z_fuid_loaded = B_TRUE;
+	rw_exit(&zfsvfs->z_fuid_lock);
+}
+
+/*
+ * sync out AVL trees to persistent storage.
+ */
+void
+zfs_fuid_sync(zfsvfs_t *zfsvfs, dmu_tx_t *tx)
+{
+	nvlist_t *nvp;
+	nvlist_t **fuids;
+	size_t nvsize = 0;
+	char *packed;
+	dmu_buf_t *db;
+	fuid_domain_t *domnode;
+	int numnodes;
+	int i;
+
+	if (!zfsvfs->z_fuid_dirty) {
+		return;
+	}
+
+	rw_enter(&zfsvfs->z_fuid_lock, RW_WRITER);
+
+	/*
+	 * First see if table needs to be created?
+	 */
+	if (zfsvfs->z_fuid_obj == 0) {
+		zfsvfs->z_fuid_obj = dmu_object_alloc(zfsvfs->z_os,
+		    DMU_OT_FUID, 1 << 14, DMU_OT_FUID_SIZE,
+		    sizeof (uint64_t), tx);
+		VERIFY(zap_add(zfsvfs->z_os, MASTER_NODE_OBJ,
+		    ZFS_FUID_TABLES, sizeof (uint64_t), 1,
+		    &zfsvfs->z_fuid_obj, tx) == 0);
+	}
+
+	VERIFY(nvlist_alloc(&nvp, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+
+	numnodes = avl_numnodes(&zfsvfs->z_fuid_idx);
+	fuids = kmem_alloc(numnodes * sizeof (void *), KM_SLEEP);
+	for (i = 0, domnode = avl_first(&zfsvfs->z_fuid_domain); domnode; i++,
+	    domnode = AVL_NEXT(&zfsvfs->z_fuid_domain, domnode)) {
+		VERIFY(nvlist_alloc(&fuids[i], NV_UNIQUE_NAME, KM_SLEEP) == 0);
+		VERIFY(nvlist_add_uint64(fuids[i], FUID_IDX,
+		    domnode->f_idx) == 0);
+		VERIFY(nvlist_add_uint64(fuids[i], FUID_OFFSET, 0) == 0);
+		VERIFY(nvlist_add_string(fuids[i], FUID_DOMAIN,
+		    domnode->f_ksid->kd_name) == 0);
+	}
+	VERIFY(nvlist_add_nvlist_array(nvp, FUID_NVP_ARRAY,
+	    fuids, numnodes) == 0);
+	for (i = 0; i != numnodes; i++)
+		nvlist_free(fuids[i]);
+	kmem_free(fuids, numnodes * sizeof (void *));
+	VERIFY(nvlist_size(nvp, &nvsize, NV_ENCODE_XDR) == 0);
+	packed = kmem_alloc(nvsize, KM_SLEEP);
+	VERIFY(nvlist_pack(nvp, &packed, &nvsize,
+	    NV_ENCODE_XDR, KM_SLEEP) == 0);
+	nvlist_free(nvp);
+	zfsvfs->z_fuid_size = nvsize;
+	dmu_write(zfsvfs->z_os, zfsvfs->z_fuid_obj, 0,
+	    zfsvfs->z_fuid_size, packed, tx);
+	kmem_free(packed, zfsvfs->z_fuid_size);
+	VERIFY(0 == dmu_bonus_hold(zfsvfs->z_os, zfsvfs->z_fuid_obj,
+	    FTAG, &db));
+	dmu_buf_will_dirty(db, tx);
+	*(uint64_t *)db->db_data = zfsvfs->z_fuid_size;
+	dmu_buf_rele(db, FTAG);
+
+	zfsvfs->z_fuid_dirty = B_FALSE;
 	rw_exit(&zfsvfs->z_fuid_lock);
 }
 
 /*
  * Query domain table for a given domain.
  *
- * If domain isn't found it is added to AVL trees and
- * the results are pushed out to disk.
+ * If domain isn't found and addok is set, it is added to AVL trees and
+ * the zfsvfs->z_fuid_dirty flag will be set to TRUE.  It will then be
+ * necessary for the caller or another thread to detect the dirty table
+ * and sync out the changes.
  */
 int
-zfs_fuid_find_by_domain(zfsvfs_t *zfsvfs, const char *domain, char **retdomain,
-    dmu_tx_t *tx)
+zfs_fuid_find_by_domain(zfsvfs_t *zfsvfs, const char *domain,
+    char **retdomain, boolean_t addok)
 {
 	fuid_domain_t searchnode, *findnode;
 	avl_index_t loc;
@@ -246,16 +313,16 @@ zfs_fuid_find_by_domain(zfsvfs_t *zfsvfs, const char *domain, char **retdomain,
 	 * for the user nobody.
 	 */
 	if (domain[0] == '\0') {
-		*retdomain = nulldomain;
+		if (retdomain)
+			*retdomain = nulldomain;
 		return (0);
 	}
 
 	searchnode.f_ksid = ksid_lookupdomain(domain);
-	if (retdomain) {
+	if (retdomain)
 		*retdomain = searchnode.f_ksid->kd_name;
-	}
 	if (!zfsvfs->z_fuid_loaded)
-		zfs_fuid_init(zfsvfs, tx);
+		zfs_fuid_init(zfsvfs);
 
 retry:
 	rw_enter(&zfsvfs->z_fuid_lock, rw);
@@ -265,15 +332,9 @@ retry:
 		rw_exit(&zfsvfs->z_fuid_lock);
 		ksiddomain_rele(searchnode.f_ksid);
 		return (findnode->f_idx);
-	} else {
+	} else if (addok) {
 		fuid_domain_t *domnode;
-		nvlist_t *nvp;
-		nvlist_t **fuids;
 		uint64_t retidx;
-		size_t nvsize = 0;
-		char *packed;
-		dmu_buf_t *db;
-		int i = 0;
 
 		if (rw == RW_READER && !rw_tryupgrade(&zfsvfs->z_fuid_lock)) {
 			rw_exit(&zfsvfs->z_fuid_lock);
@@ -288,46 +349,11 @@ retry:
 
 		avl_add(&zfsvfs->z_fuid_domain, domnode);
 		avl_add(&zfsvfs->z_fuid_idx, domnode);
-		/*
-		 * Now resync the on-disk nvlist.
-		 */
-		VERIFY(nvlist_alloc(&nvp, NV_UNIQUE_NAME, KM_SLEEP) == 0);
-
-		domnode = avl_first(&zfsvfs->z_fuid_domain);
-		fuids = kmem_alloc(retidx * sizeof (void *), KM_SLEEP);
-		while (domnode) {
-			VERIFY(nvlist_alloc(&fuids[i],
-			    NV_UNIQUE_NAME, KM_SLEEP) == 0);
-			VERIFY(nvlist_add_uint64(fuids[i], FUID_IDX,
-			    domnode->f_idx) == 0);
-			VERIFY(nvlist_add_uint64(fuids[i],
-			    FUID_OFFSET, 0) == 0);
-			VERIFY(nvlist_add_string(fuids[i++], FUID_DOMAIN,
-			    domnode->f_ksid->kd_name) == 0);
-			domnode = AVL_NEXT(&zfsvfs->z_fuid_domain, domnode);
-		}
-		VERIFY(nvlist_add_nvlist_array(nvp, FUID_NVP_ARRAY,
-		    fuids, retidx) == 0);
-		for (i = 0; i != retidx; i++)
-			nvlist_free(fuids[i]);
-		kmem_free(fuids, retidx * sizeof (void *));
-		VERIFY(nvlist_size(nvp, &nvsize, NV_ENCODE_XDR) == 0);
-		packed = kmem_alloc(nvsize, KM_SLEEP);
-		VERIFY(nvlist_pack(nvp, &packed, &nvsize,
-		    NV_ENCODE_XDR, KM_SLEEP) == 0);
-		nvlist_free(nvp);
-		zfsvfs->z_fuid_size = nvsize;
-		dmu_write(zfsvfs->z_os, zfsvfs->z_fuid_obj, 0,
-		    zfsvfs->z_fuid_size, packed, tx);
-		kmem_free(packed, zfsvfs->z_fuid_size);
-		VERIFY(0 == dmu_bonus_hold(zfsvfs->z_os, zfsvfs->z_fuid_obj,
-		    FTAG, &db));
-		dmu_buf_will_dirty(db, tx);
-		*(uint64_t *)db->db_data = zfsvfs->z_fuid_size;
-		dmu_buf_rele(db, FTAG);
-
+		zfsvfs->z_fuid_dirty = B_TRUE;
 		rw_exit(&zfsvfs->z_fuid_lock);
 		return (retidx);
+	} else {
+		return (-1);
 	}
 }
 
@@ -337,7 +363,7 @@ retry:
  * Returns a pointer from an avl node of the domain string.
  *
  */
-static char *
+const char *
 zfs_fuid_find_by_idx(zfsvfs_t *zfsvfs, uint32_t idx)
 {
 	char *domain;
@@ -346,7 +372,7 @@ zfs_fuid_find_by_idx(zfsvfs_t *zfsvfs, uint32_t idx)
 		return (NULL);
 
 	if (!zfsvfs->z_fuid_loaded)
-		zfs_fuid_init(zfsvfs, NULL);
+		zfs_fuid_init(zfsvfs);
 
 	rw_enter(&zfsvfs->z_fuid_lock, RW_READER);
 
@@ -374,7 +400,7 @@ zfs_fuid_map_id(zfsvfs_t *zfsvfs, uint64_t fuid,
     cred_t *cr, zfs_fuid_type_t type)
 {
 	uint32_t index = FUID_INDEX(fuid);
-	char *domain;
+	const char *domain;
 	uid_t id;
 
 	if (index == 0)
@@ -439,6 +465,7 @@ zfs_fuid_node_add(zfs_fuid_info_t **fuidpp, const char *domain, uint32_t rid,
 	}
 
 	if (type == ZFS_ACE_USER || type == ZFS_ACE_GROUP) {
+
 		/*
 		 * Now allocate fuid entry and add it on the end of the list
 		 */
@@ -463,7 +490,7 @@ zfs_fuid_node_add(zfs_fuid_info_t **fuidpp, const char *domain, uint32_t rid,
  */
 uint64_t
 zfs_fuid_create_cred(zfsvfs_t *zfsvfs, zfs_fuid_type_t type,
-    dmu_tx_t *tx, cred_t *cr, zfs_fuid_info_t **fuidp)
+    cred_t *cr, zfs_fuid_info_t **fuidp)
 {
 	uint64_t	idx;
 	ksid_t		*ksid;
@@ -490,7 +517,7 @@ zfs_fuid_create_cred(zfsvfs_t *zfsvfs, zfs_fuid_type_t type,
 	rid = ksid_getrid(ksid);
 	domain = ksid_getdomain(ksid);
 
-	idx = zfs_fuid_find_by_domain(zfsvfs, domain, &kdomain, tx);
+	idx = zfs_fuid_find_by_domain(zfsvfs, domain, &kdomain, B_TRUE);
 
 	zfs_fuid_node_add(fuidp, kdomain, rid, idx, id, type);
 
@@ -511,7 +538,7 @@ zfs_fuid_create_cred(zfsvfs_t *zfsvfs, zfs_fuid_type_t type,
  */
 uint64_t
 zfs_fuid_create(zfsvfs_t *zfsvfs, uint64_t id, cred_t *cr,
-    zfs_fuid_type_t type, dmu_tx_t *tx, zfs_fuid_info_t **fuidpp)
+    zfs_fuid_type_t type, zfs_fuid_info_t **fuidpp)
 {
 	const char *domain;
 	char *kdomain;
@@ -581,10 +608,11 @@ zfs_fuid_create(zfsvfs_t *zfsvfs, uint64_t id, cred_t *cr,
 		}
 	}
 
-	idx = zfs_fuid_find_by_domain(zfsvfs, domain, &kdomain, tx);
+	idx = zfs_fuid_find_by_domain(zfsvfs, domain, &kdomain, B_TRUE);
 
 	if (!zfsvfs->z_replay)
-		zfs_fuid_node_add(fuidpp, kdomain, rid, idx, id, type);
+		zfs_fuid_node_add(fuidpp, kdomain,
+		    rid, idx, id, type);
 	else if (zfuid != NULL) {
 		list_remove(&fuidp->z_fuids, zfuid);
 		kmem_free(zfuid, sizeof (zfs_fuid_t));
@@ -658,16 +686,15 @@ boolean_t
 zfs_groupmember(zfsvfs_t *zfsvfs, uint64_t id, cred_t *cr)
 {
 	ksid_t		*ksid = crgetsid(cr, KSID_GROUP);
+	ksidlist_t	*ksidlist = crgetsidlist(cr);
 	uid_t		gid;
 
-	if (ksid) {
+	if (ksid && ksidlist) {
 		int 		i;
 		ksid_t		*ksid_groups;
-		ksidlist_t	*ksidlist = crgetsidlist(cr);
 		uint32_t	idx = FUID_INDEX(id);
 		uint32_t	rid = FUID_RID(id);
 
-		ASSERT(ksidlist);
 		ksid_groups = ksidlist->ksl_sids;
 
 		for (i = 0; i != ksidlist->ksl_nsid; i++) {
@@ -677,7 +704,7 @@ zfs_groupmember(zfsvfs_t *zfsvfs, uint64_t id, cred_t *cr)
 					return (B_TRUE);
 				}
 			} else {
-				char *domain;
+				const char *domain;
 
 				domain = zfs_fuid_find_by_idx(zfsvfs, idx);
 				ASSERT(domain != NULL);
@@ -700,4 +727,19 @@ zfs_groupmember(zfsvfs_t *zfsvfs, uint64_t id, cred_t *cr)
 	gid = zfs_fuid_map_id(zfsvfs, id, cr, ZFS_GROUP);
 	return (groupmember(gid, cr));
 }
+
+void
+zfs_fuid_txhold(zfsvfs_t *zfsvfs, dmu_tx_t *tx)
+{
+	if (zfsvfs->z_fuid_obj == 0) {
+		dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
+		dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0,
+		    FUID_SIZE_ESTIMATE(zfsvfs));
+		dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, FALSE, NULL);
+	} else {
+		dmu_tx_hold_bonus(tx, zfsvfs->z_fuid_obj);
+		dmu_tx_hold_write(tx, zfsvfs->z_fuid_obj, 0,
+		    FUID_SIZE_ESTIMATE(zfsvfs));
+	}
+}
 #endif
diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index d032648b5..07dd03c35 100644
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -79,17 +79,29 @@ dev_info_t *zfs_dip;
 typedef int zfs_ioc_func_t(zfs_cmd_t *);
 typedef int zfs_secpolicy_func_t(zfs_cmd_t *, cred_t *);
 
+typedef enum {
+	NO_NAME,
+	POOL_NAME,
+	DATASET_NAME
+} zfs_ioc_namecheck_t;
+
 typedef struct zfs_ioc_vec {
 	zfs_ioc_func_t		*zvec_func;
 	zfs_secpolicy_func_t	*zvec_secpolicy;
-	enum {
-		NO_NAME,
-		POOL_NAME,
-		DATASET_NAME
-	} zvec_namecheck;
+	zfs_ioc_namecheck_t	zvec_namecheck;
 	boolean_t		zvec_his_log;
+	boolean_t		zvec_pool_check;
 } zfs_ioc_vec_t;
 
+/* This array is indexed by zfs_userquota_prop_t */
+static const char *userquota_perms[] = {
+	ZFS_DELEG_PERM_USERUSED,
+	ZFS_DELEG_PERM_USERQUOTA,
+	ZFS_DELEG_PERM_GROUPUSED,
+	ZFS_DELEG_PERM_GROUPQUOTA,
+};
+
+static int zfs_ioc_userspace_upgrade(zfs_cmd_t *zc);
 static void clear_props(char *dataset, nvlist_t *props, nvlist_t *newprops);
 static int zfs_fill_zplprops_root(uint64_t, nvlist_t *, nvlist_t *,
     boolean_t *);
@@ -389,6 +401,30 @@ zfs_secpolicy_send(zfs_cmd_t *zc, cred_t *cr)
 	    ZFS_DELEG_PERM_SEND, cr));
 }
 
+static int
+zfs_secpolicy_deleg_share(zfs_cmd_t *zc, cred_t *cr)
+{
+	vnode_t *vp;
+	int error;
+
+	if ((error = lookupname(zc->zc_value, UIO_SYSSPACE,
+	    NO_FOLLOW, NULL, &vp)) != 0)
+		return (error);
+
+	/* Now make sure mntpnt and dataset are ZFS */
+
+	if (vp->v_vfsp->vfs_fstype != zfsfstype ||
+	    (strcmp((char *)refstr_value(vp->v_vfsp->vfs_resource),
+	    zc->zc_name) != 0)) {
+		VN_RELE(vp);
+		return (EPERM);
+	}
+
+	VN_RELE(vp);
+	return (dsl_deleg_access(zc->zc_name,
+	    ZFS_DELEG_PERM_SHARE, cr));
+}
+
 int
 zfs_secpolicy_share(zfs_cmd_t *zc, cred_t *cr)
 {
@@ -398,25 +434,20 @@ zfs_secpolicy_share(zfs_cmd_t *zc, cred_t *cr)
 	if (secpolicy_nfs(cr) == 0) {
 		return (0);
 	} else {
-		vnode_t *vp;
-		int error;
-
-		if ((error = lookupname(zc->zc_value, UIO_SYSSPACE,
-		    NO_FOLLOW, NULL, &vp)) != 0)
-			return (error);
-
-		/* Now make sure mntpnt and dataset are ZFS */
+		return (zfs_secpolicy_deleg_share(zc, cr));
+	}
+}
 
-		if (vp->v_vfsp->vfs_fstype != zfsfstype ||
-		    (strcmp((char *)refstr_value(vp->v_vfsp->vfs_resource),
-		    zc->zc_name) != 0)) {
-			VN_RELE(vp);
-			return (EPERM);
-		}
+int
+zfs_secpolicy_smb_acl(zfs_cmd_t *zc, cred_t *cr)
+{
+	if (!INGLOBALZONE(curproc))
+		return (EPERM);
 
-		VN_RELE(vp);
-		return (dsl_deleg_access(zc->zc_name,
-		    ZFS_DELEG_PERM_SHARE, cr));
+	if (secpolicy_smb(cr) == 0) {
+		return (0);
+	} else {
+		return (zfs_secpolicy_deleg_share(zc, cr));
 	}
 }
 
@@ -681,11 +712,60 @@ zfs_secpolicy_inherit(zfs_cmd_t *zc, cred_t *cr)
 	}
 }
 
+static int
+zfs_secpolicy_userspace_one(zfs_cmd_t *zc, cred_t *cr)
+{
+	int err = zfs_secpolicy_read(zc, cr);
+	if (err)
+		return (err);
+
+	if (zc->zc_objset_type >= ZFS_NUM_USERQUOTA_PROPS)
+		return (EINVAL);
+
+	if (zc->zc_value[0] == 0) {
+		/*
+		 * They are asking about a posix uid/gid.  If it's
+		 * themself, allow it.
+		 */
+		if (zc->zc_objset_type == ZFS_PROP_USERUSED ||
+		    zc->zc_objset_type == ZFS_PROP_USERQUOTA) {
+			if (zc->zc_guid == crgetuid(cr))
+				return (0);
+		} else {
+			if (groupmember(zc->zc_guid, cr))
+				return (0);
+		}
+	}
+
+	return (zfs_secpolicy_write_perms(zc->zc_name,
+	    userquota_perms[zc->zc_objset_type], cr));
+}
+
+static int
+zfs_secpolicy_userspace_many(zfs_cmd_t *zc, cred_t *cr)
+{
+	int err = zfs_secpolicy_read(zc, cr);
+	if (err)
+		return (err);
+
+	if (zc->zc_objset_type >= ZFS_NUM_USERQUOTA_PROPS)
+		return (EINVAL);
+
+	return (zfs_secpolicy_write_perms(zc->zc_name,
+	    userquota_perms[zc->zc_objset_type], cr));
+}
+
+static int
+zfs_secpolicy_userspace_upgrade(zfs_cmd_t *zc, cred_t *cr)
+{
+	return (zfs_secpolicy_setprop(zc->zc_name, ZFS_PROP_VERSION, cr));
+}
+
 /*
  * Returns the nvlist as specified by the user in the zfs_cmd_t.
  */
 static int
-get_nvlist(uint64_t nvl, uint64_t size, nvlist_t **nvp)
+get_nvlist(uint64_t nvl, uint64_t size, int iflag, nvlist_t **nvp)
 {
 	char *packed;
 	int error;
@@ -699,7 +779,8 @@ get_nvlist(uint64_t nvl, uint64_t size, nvlist_t **nvp)
 
 	packed = kmem_alloc(size, KM_SLEEP);
 
-	if ((error = xcopyin((void *)(uintptr_t)nvl, packed, size)) != 0) {
+	if ((error = ddi_copyin((void *)(uintptr_t)nvl, packed, size,
+	    iflag)) != 0) {
 		kmem_free(packed, size);
 		return (error);
 	}
@@ -730,8 +811,8 @@ put_nvlist(zfs_cmd_t *zc, nvlist_t *nvl)
 		packed = kmem_alloc(size, KM_SLEEP);
 		VERIFY(nvlist_pack(nvl, &packed, &size, NV_ENCODE_NATIVE,
 		    KM_SLEEP) == 0);
-		error = xcopyout(packed, (void *)(uintptr_t)zc->zc_nvlist_dst,
-		    size);
+		error = ddi_copyout(packed,
+		    (void *)(uintptr_t)zc->zc_nvlist_dst, size, zc->zc_iflags);
 		kmem_free(packed, size);
 	}
 
@@ -740,6 +821,69 @@ put_nvlist(zfs_cmd_t *zc, nvlist_t *nvl)
 }
 
 static int
+getzfsvfs(const char *dsname, zfsvfs_t **zvp)
+{
+	objset_t *os;
+	int error;
+
+	error = dmu_objset_open(dsname, DMU_OST_ZFS,
+	    DS_MODE_USER | DS_MODE_READONLY, &os);
+	if (error)
+		return (error);
+
+	mutex_enter(&os->os->os_user_ptr_lock);
+	*zvp = dmu_objset_get_user(os);
+	if (*zvp) {
+		VFS_HOLD((*zvp)->z_vfs);
+	} else {
+		error = ESRCH;
+	}
+	mutex_exit(&os->os->os_user_ptr_lock);
+	dmu_objset_close(os);
+	return (error);
+}
+
+/*
+ * Find a zfsvfs_t for a mounted filesystem, or create our own, in which
+ * case its z_vfs will be NULL, and it will be opened as the owner.
+ */
+static int
+zfsvfs_hold(const char *name, boolean_t readonly, void *tag, zfsvfs_t **zvp)
+{
+	int error = 0;
+	int mode = DS_MODE_OWNER | (readonly ? DS_MODE_READONLY : 0);
+
+	if (getzfsvfs(name, zvp) != 0)
+		error = zfsvfs_create(name, mode, zvp);
+	if (error == 0) {
+		rrw_enter(&(*zvp)->z_teardown_lock, RW_READER, tag);
+		if ((*zvp)->z_unmounted) {
+			/*
+			 * XXX we could probably try again, since the unmounting
+			 * thread should be just about to disassociate the
+			 * objset from the zfsvfs.
+			 */
+			rrw_exit(&(*zvp)->z_teardown_lock, tag);
+			return (EBUSY);
+		}
+	}
+	return (error);
+}
+
+static void
+zfsvfs_rele(zfsvfs_t *zfsvfs, void *tag)
+{
+	rrw_exit(&zfsvfs->z_teardown_lock, tag);
+
+	if (zfsvfs->z_vfs) {
+		VFS_RELE(zfsvfs->z_vfs);
+	} else {
+		dmu_objset_close(zfsvfs->z_os);
+		zfsvfs_free(zfsvfs);
+	}
+}
+
+static int
 zfs_ioc_pool_create(zfs_cmd_t *zc)
 {
 	int error;
@@ -749,11 +893,12 @@ zfs_ioc_pool_create(zfs_cmd_t *zc)
 	char *buf;
 
 	if (error = get_nvlist(zc->zc_nvlist_conf, zc->zc_nvlist_conf_size,
-	    &config))
+	    zc->zc_iflags, &config))
 		return (error);
 
 	if (zc->zc_nvlist_src_size != 0 && (error =
-	    get_nvlist(zc->zc_nvlist_src, zc->zc_nvlist_src_size, &props))) {
+	    get_nvlist(zc->zc_nvlist_src, zc->zc_nvlist_src_size,
+	    zc->zc_iflags, &props))) {
 		nvlist_free(config);
 		return (error);
 	}
@@ -825,11 +970,12 @@ zfs_ioc_pool_import(zfs_cmd_t *zc)
 	uint64_t guid;
 
 	if ((error = get_nvlist(zc->zc_nvlist_conf, zc->zc_nvlist_conf_size,
-	    &config)) != 0)
+	    zc->zc_iflags, &config)) != 0)
 		return (error);
 
 	if (zc->zc_nvlist_src_size != 0 && (error =
-	    get_nvlist(zc->zc_nvlist_src, zc->zc_nvlist_src_size, &props))) {
+	    get_nvlist(zc->zc_nvlist_src, zc->zc_nvlist_src_size,
+	    zc->zc_iflags, &props))) {
 		nvlist_free(config);
 		return (error);
 	}
@@ -838,7 +984,7 @@ zfs_ioc_pool_import(zfs_cmd_t *zc)
 	    guid != zc->zc_guid)
 		error = EINVAL;
 	else if (zc->zc_cookie)
-		error = spa_import_faulted(zc->zc_name, config,
+		error = spa_import_verbatim(zc->zc_name, config,
 		    props);
 	else
 		error = spa_import(zc->zc_name, config, props);
@@ -917,7 +1063,7 @@ zfs_ioc_pool_tryimport(zfs_cmd_t *zc)
 	int error;
 
 	if ((error = get_nvlist(zc->zc_nvlist_conf, zc->zc_nvlist_conf_size,
-	    &tryconfig)) != 0)
+	    zc->zc_iflags, &tryconfig)) != 0)
 		return (error);
 
 	config = spa_tryimport(tryconfig);
@@ -1005,9 +1151,9 @@ zfs_ioc_pool_get_history(zfs_cmd_t *zc)
 	hist_buf = kmem_alloc(size, KM_SLEEP);
 	if ((error = spa_history_get(spa, &zc->zc_history_offset,
 	    &zc->zc_history_len, hist_buf)) == 0) {
-		error = xcopyout(hist_buf,
-		    (char *)(uintptr_t)zc->zc_history,
-		    zc->zc_history_len);
+		error = ddi_copyout(hist_buf,
+		    (void *)(uintptr_t)zc->zc_history,
+		    zc->zc_history_len, zc->zc_iflags);
 	}
 
 	spa_close(spa, FTAG);
@@ -1055,7 +1201,7 @@ zfs_ioc_vdev_add(zfs_cmd_t *zc)
 		return (error);
 
 	error = get_nvlist(zc->zc_nvlist_conf, zc->zc_nvlist_conf_size,
-	    &config);
+	    zc->zc_iflags, &config);
 	(void) nvlist_lookup_nvlist_array(config, ZPOOL_CONFIG_L2CACHE,
 	    &l2cache, &nl2cache);
 
@@ -1145,7 +1291,7 @@ zfs_ioc_vdev_attach(zfs_cmd_t *zc)
 		return (error);
 
 	if ((error = get_nvlist(zc->zc_nvlist_conf, zc->zc_nvlist_conf_size,
-	    &config)) == 0) {
+	    zc->zc_iflags, &config)) == 0) {
 		error = spa_vdev_attach(spa, zc->zc_guid, config, replacing);
 		nvlist_free(config);
 	}
@@ -1186,6 +1332,23 @@ zfs_ioc_vdev_setpath(zfs_cmd_t *zc)
 	return (error);
 }
 
+static int
+zfs_ioc_vdev_setfru(zfs_cmd_t *zc)
+{
+	spa_t *spa;
+	char *fru = zc->zc_value;
+	uint64_t guid = zc->zc_guid;
+	int error;
+
+	error = spa_open(zc->zc_name, &spa, FTAG);
+	if (error != 0)
+		return (error);
+
+	error = spa_vdev_setfru(spa, guid, fru);
+	spa_close(spa, FTAG);
+	return (error);
+}
+
 /*
  * inputs:
  * zc_name		name of filesystem
@@ -1291,6 +1454,23 @@ zfs_ioc_objset_zplprops(zfs_cmd_t *zc)
 	return (err);
 }
 
+static boolean_t
+dataset_name_hidden(const char *name)
+{
+	/*
+	 * Skip over datasets that are not visible in this zone,
+	 * internal datasets (which have a $ in their name), and
+	 * temporary datasets (which have a % in their name).
+	 */
+	if (strchr(name, '$') != NULL)
+		return (B_TRUE);
+	if (strchr(name, '%') != NULL)
+		return (B_TRUE);
+	if (!INGLOBALZONE(curproc) && !zone_dataset_visible(name, NULL))
+		return (B_TRUE);
+	return (B_FALSE);
+}
+
 /*
  * inputs:
  * zc_name		name of filesystem
@@ -1299,6 +1479,7 @@ zfs_ioc_objset_zplprops(zfs_cmd_t *zc)
  *
  * outputs:
  * zc_name		name of next filesystem
+ * zc_cookie		zap cursor
  * zc_objset_stats	stats
  * zc_nvlist_dst	property nvlist
  * zc_nvlist_dst_size	size of property nvlist
@@ -1322,12 +1503,16 @@ zfs_ioc_dataset_list_next(zfs_cmd_t *zc)
 		(void) strlcat(zc->zc_name, "/", sizeof (zc->zc_name));
 	p = zc->zc_name + strlen(zc->zc_name);
 
+	/*
+	 * Pre-fetch the datasets.  dmu_objset_prefetch() always returns 0
+	 * but is not declared void because its called by dmu_objset_find().
+	 */
 	if (zc->zc_cookie == 0) {
 		uint64_t cookie = 0;
 		int len = sizeof (zc->zc_name) - (p - zc->zc_name);
 
 		while (dmu_dir_list_next(os, len, p, NULL, &cookie) == 0)
-			dmu_objset_prefetch(p, NULL);
+			(void) dmu_objset_prefetch(p, NULL);
 	}
 
 	do {
@@ -1336,15 +1521,10 @@ zfs_ioc_dataset_list_next(zfs_cmd_t *zc)
 		    NULL, &zc->zc_cookie);
 		if (error == ENOENT)
 			error = ESRCH;
-	} while (error == 0 && !INGLOBALZONE(curproc) &&
-	    !zone_dataset_visible(zc->zc_name, NULL));
+	} while (error == 0 && dataset_name_hidden(zc->zc_name));
 	dmu_objset_close(os);
 
-	/*
-	 * If it's a hidden dataset (ie. with a '$' in its name), don't
-	 * try to get stats for it.  Userland will skip over it.
-	 */
-	if (error == 0 && strchr(zc->zc_name, '$') == NULL)
+	if (error == 0)
 		error = zfs_ioc_objset_stats(zc); /* fill in the stats */
 
 	return (error);
@@ -1373,9 +1553,10 @@ zfs_ioc_snapshot_list_next(zfs_cmd_t *zc)
 	if (error)
 		return (error == ENOENT ? ESRCH : error);
 
-	if (zc->zc_cookie == 0)
-		dmu_objset_find(zc->zc_name, dmu_objset_prefetch,
+	if (zc->zc_cookie == 0) {
+		(void) dmu_objset_find(zc->zc_name, dmu_objset_prefetch,
 		    NULL, DS_FIND_SNAPSHOTS);
+	}
 	/*
 	 * A dataset name of maximum length cannot have any snapshots,
 	 * so exit immediately.
@@ -1404,9 +1585,11 @@ int
 zfs_set_prop_nvlist(const char *name, nvlist_t *nvl)
 {
 	nvpair_t *elem;
-	int error;
+	int error = 0;
 	uint64_t intval;
 	char *strval;
+	nvlist_t *genericnvl;
+	boolean_t issnap = (strchr(name, '@') != NULL);
 
 	/*
 	 * First validate permission to set all of the properties
@@ -1421,16 +1604,35 @@ zfs_set_prop_nvlist(const char *name, nvlist_t *nvl)
 			 * If this is a user-defined property, it must be a
 			 * string, and there is no further validation to do.
 			 */
-			if (!zfs_prop_user(propname) ||
-			    nvpair_type(elem) != DATA_TYPE_STRING)
-				return (EINVAL);
+			if (zfs_prop_user(propname) &&
+			    nvpair_type(elem) == DATA_TYPE_STRING) {
+				if (error = zfs_secpolicy_write_perms(name,
+				    ZFS_DELEG_PERM_USERPROP, CRED()))
+					return (error);
+				continue;
+			}
 
-			if (error = zfs_secpolicy_write_perms(name,
-			    ZFS_DELEG_PERM_USERPROP, CRED()))
-				return (error);
-			continue;
+			if (!issnap && zfs_prop_userquota(propname) &&
+			    nvpair_type(elem) == DATA_TYPE_UINT64_ARRAY) {
+				const char *perm;
+				const char *up = zfs_userquota_prop_prefixes
+				    [ZFS_PROP_USERQUOTA];
+				if (strncmp(propname, up, strlen(up)) == 0)
+					perm = ZFS_DELEG_PERM_USERQUOTA;
+				else
+					perm = ZFS_DELEG_PERM_GROUPQUOTA;
+				if (error = zfs_secpolicy_write_perms(name,
+				    perm, CRED()))
+					return (error);
+				continue;
+			}
+
+			return (EINVAL);
 		}
 
+		if (issnap)
+			return (EINVAL);
+
 		if ((error = zfs_secpolicy_setprop(name, prop, CRED())) != 0)
 			return (error);
 
@@ -1466,8 +1668,7 @@ zfs_set_prop_nvlist(const char *name, nvlist_t *nvl)
 			break;
 
 		case ZFS_PROP_COPIES:
-			if (zfs_earlier_version(name,
-			    SPA_VERSION_DITTO_BLOCKS))
+			if (zfs_earlier_version(name, SPA_VERSION_DITTO_BLOCKS))
 				return (ENOTSUP);
 			break;
 
@@ -1486,77 +1687,122 @@ zfs_set_prop_nvlist(const char *name, nvlist_t *nvl)
 		}
 	}
 
+	VERIFY(nvlist_alloc(&genericnvl, NV_UNIQUE_NAME, KM_SLEEP) == 0);
 	elem = NULL;
 	while ((elem = nvlist_next_nvpair(nvl, elem)) != NULL) {
 		const char *propname = nvpair_name(elem);
 		zfs_prop_t prop = zfs_name_to_prop(propname);
 
 		if (prop == ZPROP_INVAL) {
-			VERIFY(nvpair_value_string(elem, &strval) == 0);
-			error = dsl_prop_set(name, propname, 1,
-			    strlen(strval) + 1, strval);
-			if (error == 0)
-				continue;
-			else
-				return (error);
+			if (zfs_prop_userquota(propname)) {
+				uint64_t *valary;
+				unsigned int vallen;
+				const char *domain;
+				zfs_userquota_prop_t type;
+				uint64_t rid;
+				uint64_t quota;
+				zfsvfs_t *zfsvfs;
+
+				VERIFY(nvpair_value_uint64_array(elem,
+				    &valary, &vallen) == 0);
+				VERIFY(vallen == 3);
+				type = valary[0];
+				rid = valary[1];
+				quota = valary[2];
+				domain = propname +
+				    strlen(zfs_userquota_prop_prefixes[type]);
+
+				error = zfsvfs_hold(name, B_FALSE, FTAG,
+				    &zfsvfs);
+				if (error == 0) {
+					error = zfs_set_userquota(zfsvfs,
+					    type, domain, rid, quota);
+					zfsvfs_rele(zfsvfs, FTAG);
+				}
+				if (error == 0)
+					continue;
+				else
+					goto out;
+			} else if (zfs_prop_user(propname)) {
+				VERIFY(nvpair_value_string(elem, &strval) == 0);
+				error = dsl_prop_set(name, propname, 1,
+				    strlen(strval) + 1, strval);
+				if (error == 0)
+					continue;
+				else
+					goto out;
+			}
 		}
 
 		switch (prop) {
 		case ZFS_PROP_QUOTA:
 			if ((error = nvpair_value_uint64(elem, &intval)) != 0 ||
 			    (error = dsl_dir_set_quota(name, intval)) != 0)
-				return (error);
+				goto out;
 			break;
 
 		case ZFS_PROP_REFQUOTA:
 			if ((error = nvpair_value_uint64(elem, &intval)) != 0 ||
 			    (error = dsl_dataset_set_quota(name, intval)) != 0)
-				return (error);
+				goto out;
 			break;
 
 		case ZFS_PROP_RESERVATION:
 			if ((error = nvpair_value_uint64(elem, &intval)) != 0 ||
 			    (error = dsl_dir_set_reservation(name,
 			    intval)) != 0)
-				return (error);
+				goto out;
 			break;
 
 		case ZFS_PROP_REFRESERVATION:
 			if ((error = nvpair_value_uint64(elem, &intval)) != 0 ||
 			    (error = dsl_dataset_set_reservation(name,
 			    intval)) != 0)
-				return (error);
+				goto out;
 			break;
 
 		case ZFS_PROP_VOLSIZE:
 			if ((error = nvpair_value_uint64(elem, &intval)) != 0 ||
 			    (error = zvol_set_volsize(name,
 			    ddi_driver_major(zfs_dip), intval)) != 0)
-				return (error);
+				goto out;
 			break;
 
 		case ZFS_PROP_VOLBLOCKSIZE:
 			if ((error = nvpair_value_uint64(elem, &intval)) != 0 ||
 			    (error = zvol_set_volblocksize(name, intval)) != 0)
-				return (error);
+				goto out;
 			break;
 
 		case ZFS_PROP_VERSION:
-			if ((error = nvpair_value_uint64(elem, &intval)) != 0 ||
-			    (error = zfs_set_version(name, intval)) != 0)
-				return (error);
+		{
+			zfsvfs_t *zfsvfs;
+
+			if ((error = nvpair_value_uint64(elem, &intval)) != 0)
+				goto out;
+			if ((error = zfsvfs_hold(name, B_FALSE, FTAG,
+			    &zfsvfs)) != 0)
+				goto out;
+			error = zfs_set_version(zfsvfs, intval);
+			zfsvfs_rele(zfsvfs, FTAG);
+
+			if (error == 0 && intval >= ZPL_VERSION_USERSPACE) {
+				zfs_cmd_t zc = { 0 };
+				(void) strcpy(zc.zc_name, name);
+				(void) zfs_ioc_userspace_upgrade(&zc);
+			}
+			if (error)
+				goto out;
 			break;
+		}
 
 		default:
 			if (nvpair_type(elem) == DATA_TYPE_STRING) {
 				if (zfs_prop_get_type(prop) !=
-				    PROP_TYPE_STRING)
-					return (EINVAL);
-				VERIFY(nvpair_value_string(elem, &strval) == 0);
-				if ((error = dsl_prop_set(name,
-				    nvpair_name(elem), 1, strlen(strval) + 1,
-				    strval)) != 0)
-					return (error);
+				    PROP_TYPE_STRING) {
+					error = EINVAL;
+					goto out;
+				}
 			} else if (nvpair_type(elem) == DATA_TYPE_UINT64) {
 				const char *unused;
 
@@ -1566,35 +1812,72 @@ zfs_set_prop_nvlist(const char *name, nvlist_t *nvl)
 				case PROP_TYPE_NUMBER:
 					break;
 				case PROP_TYPE_STRING:
-					return (EINVAL);
+					error = EINVAL;
+					goto out;
 				case PROP_TYPE_INDEX:
 					if (zfs_prop_index_to_string(prop,
-					    intval, &unused) != 0)
-						return (EINVAL);
+					    intval, &unused) != 0) {
+						error = EINVAL;
+						goto out;
+					}
 					break;
 				default:
 					cmn_err(CE_PANIC,
 					    "unknown property type");
 					break;
 				}
-
-				if ((error = dsl_prop_set(name, propname,
-				    8, 1, &intval)) != 0)
-					return (error);
 			} else {
-				return (EINVAL);
+				error = EINVAL;
+				goto out;
 			}
-			break;
+			if ((error = nvlist_add_nvpair(genericnvl, elem)) != 0)
+				goto out;
 		}
 	}
 
+	if (nvlist_next_nvpair(genericnvl, NULL) != NULL) {
+		error = dsl_props_set(name, genericnvl);
+	}
+out:
+	nvlist_free(genericnvl);
+	return (error);
+}
+
+/*
+ * Check that all the properties are valid user properties.
+ */
+static int
+zfs_check_userprops(char *fsname, nvlist_t *nvl)
+{
+	nvpair_t *elem = NULL;
+	int error = 0;
+
+	while ((elem = nvlist_next_nvpair(nvl, elem)) != NULL) {
+		const char *propname = nvpair_name(elem);
+		char *valstr;
+
+		if (!zfs_prop_user(propname) ||
+		    nvpair_type(elem) != DATA_TYPE_STRING)
+			return (EINVAL);
+
+		if (error = zfs_secpolicy_write_perms(fsname,
+		    ZFS_DELEG_PERM_USERPROP, CRED()))
+			return (error);
+
+		if (strlen(propname) >= ZAP_MAXNAMELEN)
+			return (ENAMETOOLONG);
+
+		VERIFY(nvpair_value_string(elem, &valstr) == 0);
+		if (strlen(valstr) >= ZAP_MAXVALUELEN)
+			return (E2BIG);
+	}
 	return (0);
 }
 
 /*
  * inputs:
  * zc_name		name of filesystem
- * zc_value		name of property to inherit
+ * zc_value		name of property to set
  * zc_nvlist_src{_size}	nvlist of properties to apply
  * zc_cookie		clear existing local props?
  *
@@ -1607,7 +1890,7 @@ zfs_ioc_set_prop(zfs_cmd_t *zc)
 	int error;
 
 	if ((error = get_nvlist(zc->zc_nvlist_src, zc->zc_nvlist_src_size,
-	    &nvl)) != 0)
+	    zc->zc_iflags, &nvl)) != 0)
 		return (error);
 
 	if (zc->zc_cookie) {
@@ -1654,7 +1937,7 @@ zfs_ioc_pool_set_props(zfs_cmd_t *zc)
 	nvpair_t *elem;
 
 	if ((error = get_nvlist(zc->zc_nvlist_src, zc->zc_nvlist_src_size,
-	    &props)))
+	    zc->zc_iflags, &props)))
 		return (error);
 
 	/*
@@ -1731,7 +2014,7 @@ zfs_ioc_iscsi_perm_check(zfs_cmd_t *zc)
 	cred_t	*usercred;
 
 	if ((error = get_nvlist(zc->zc_nvlist_src, zc->zc_nvlist_src_size,
-	    &nvp)) != 0) {
+	    zc->zc_iflags, &nvp)) != 0) {
 		return (error);
 	}
 
@@ -1781,7 +2064,7 @@ zfs_ioc_set_fsacl(zfs_cmd_t *zc)
 	nvlist_t *fsaclnv = NULL;
 
 	if ((error = get_nvlist(zc->zc_nvlist_src, zc->zc_nvlist_src_size,
-	    &fsaclnv)) != 0)
+	    zc->zc_iflags, &fsaclnv)) != 0)
 		return (error);
 
 	/*
@@ -1918,11 +2201,10 @@ zfs_create_cb(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx)
  * processing.
  */
 static int
-zfs_fill_zplprops_impl(objset_t *os, uint64_t default_zplver,
+zfs_fill_zplprops_impl(objset_t *os, uint64_t zplver,
     boolean_t fuids_ok, nvlist_t *createprops, nvlist_t *zplprops,
     boolean_t *is_ci)
 {
-	uint64_t zplver = default_zplver;
 	uint64_t sense = ZFS_PROP_UNDEFINED;
 	uint64_t norm = ZFS_PROP_UNDEFINED;
 	uint64_t u8 = ZFS_PROP_UNDEFINED;
@@ -2010,6 +2292,8 @@ zfs_fill_zplprops(const char *dataset, nvlist_t *createprops,
 	ASSERT(cp != NULL);
 	cp[0] = '\0';
 
+	if (zfs_earlier_version(dataset, SPA_VERSION_USERSPACE))
+		zplver = ZPL_VERSION_USERSPACE - 1;
 	if (zfs_earlier_version(dataset, SPA_VERSION_FUID)) {
 		zplver = ZPL_VERSION_FUID - 1;
 		fuids_ok = B_FALSE;
@@ -2085,7 +2369,7 @@ zfs_ioc_create(zfs_cmd_t *zc)
 
 	if (zc->zc_nvlist_src != NULL &&
 	    (error = get_nvlist(zc->zc_nvlist_src, zc->zc_nvlist_src_size,
-	    &nvprops)) != 0)
+	    zc->zc_iflags, &nvprops)) != 0)
 		return (error);
 
 	zct.zct_zplprops = NULL;
@@ -2188,32 +2472,12 @@ zfs_ioc_create(zfs_cmd_t *zc)
 	return (error);
 }
 
-struct snap_prop_arg {
-	nvlist_t *nvprops;
-	const char *snapname;
-};
-
-static int
-set_snap_props(char *name, void *arg)
-{
-	struct snap_prop_arg *snpa = arg;
-	int len = strlen(name) + strlen(snpa->snapname) + 2;
-	char *buf = kmem_alloc(len, KM_SLEEP);
-	int err;
-
-	(void) snprintf(buf, len, "%s@%s", name, snpa->snapname);
-	err = zfs_set_prop_nvlist(buf, snpa->nvprops);
-	if (err)
-		(void) dmu_objset_destroy(buf);
-	kmem_free(buf, len);
-	return (err);
-}
-
 /*
  * inputs:
  * zc_name	name of filesystem
  * zc_value	short name of snapshot
  * zc_cookie	recursive flag
+ * zc_nvlist_src[_size] property list
  *
  * outputs:	none
  */
@@ -2229,29 +2493,23 @@ zfs_ioc_snapshot(zfs_cmd_t *zc)
 
 	if (zc->zc_nvlist_src != NULL &&
 	    (error = get_nvlist(zc->zc_nvlist_src, zc->zc_nvlist_src_size,
-	    &nvprops)) != 0)
+	    zc->zc_iflags, &nvprops)) != 0)
 		return (error);
 
-	error = dmu_objset_snapshot(zc->zc_name, zc->zc_value, recursive);
+	error = zfs_check_userprops(zc->zc_name, nvprops);
+	if (error)
+		goto out;
 
-	/*
-	 * It would be nice to do this atomically.
-	 */
-	if (error == 0) {
-		struct snap_prop_arg snpa;
-		snpa.nvprops = nvprops;
-		snpa.snapname = zc->zc_value;
-		if (recursive) {
-			error = dmu_objset_find(zc->zc_name,
-			    set_snap_props, &snpa, DS_FIND_CHILDREN);
-			if (error) {
-				(void) dmu_snapshots_destroy(zc->zc_name,
-				    zc->zc_value);
-			}
-		} else {
-			error = set_snap_props(zc->zc_name, &snpa);
-		}
+	if (nvprops != NULL && nvlist_next_nvpair(nvprops, NULL) != NULL &&
+	    zfs_earlier_version(zc->zc_name, SPA_VERSION_SNAP_PROPS)) {
+		error = ENOTSUP;
+		goto out;
 	}
+
+	error = dmu_objset_snapshot(zc->zc_name, zc->zc_value,
+	    nvprops, recursive);
+
+out:
 	nvlist_free(nvprops);
 	return (error);
 }
@@ -2355,31 +2613,19 @@ zfs_ioc_rollback(zfs_cmd_t *zc)
 	if (error)
 		return (error);
 
-	if (dmu_objset_type(os) == DMU_OST_ZFS) {
-		mutex_enter(&os->os->os_user_ptr_lock);
-		zfsvfs = dmu_objset_get_user(os);
-		if (zfsvfs != NULL)
-			VFS_HOLD(zfsvfs->z_vfs);
-		mutex_exit(&os->os->os_user_ptr_lock);
-	}
-
-	if (zfsvfs != NULL) {
-		char *osname;
+	if (getzfsvfs(zc->zc_name, &zfsvfs) == 0) {
 		int mode;
 
-		osname = kmem_alloc(MAXNAMELEN, KM_SLEEP);
-		error = zfs_suspend_fs(zfsvfs, osname, &mode);
+		error = zfs_suspend_fs(zfsvfs, NULL, &mode);
 		if (error == 0) {
 			int resume_err;
 
-			ASSERT(strcmp(osname, zc->zc_name) == 0);
 			error = dmu_objset_rollback(os);
-			resume_err = zfs_resume_fs(zfsvfs, osname, mode);
+			resume_err = zfs_resume_fs(zfsvfs, zc->zc_name, mode);
 			error = error ? error : resume_err;
 		} else {
 			dmu_objset_close(os);
 		}
-		kmem_free(osname, MAXNAMELEN);
 		VFS_RELE(zfsvfs->z_vfs);
 	} else {
 		error = dmu_objset_rollback(os);
@@ -2484,7 +2730,7 @@ zfs_ioc_recv(zfs_cmd_t *zc)
 
 	if (zc->zc_nvlist_src != NULL &&
 	    (error = get_nvlist(zc->zc_nvlist_src, zc->zc_nvlist_src_size,
-	    &props)) != 0)
+	    zc->zc_iflags, &props)) != 0)
 		return (error);
 
 	fd = zc->zc_cookie;
@@ -2494,32 +2740,26 @@ zfs_ioc_recv(zfs_cmd_t *zc)
 		return (EBADF);
 	}
 
-	if (dmu_objset_open(tofs, DMU_OST_ANY,
-	    DS_MODE_USER | DS_MODE_READONLY, &os) == 0) {
-		/*
-		 * Try to get the zfsvfs for the receiving objset.
-		 * There won't be one if we're operating on a zvol,
-		 * if the objset doesn't exist yet, or is not mounted.
-		 */
-		mutex_enter(&os->os->os_user_ptr_lock);
-		if (zfsvfs = dmu_objset_get_user(os)) {
-			if (!mutex_tryenter(&zfsvfs->z_online_recv_lock)) {
-				mutex_exit(&os->os->os_user_ptr_lock);
-				dmu_objset_close(os);
-				zfsvfs = NULL;
-				error = EBUSY;
-				goto out;
-			}
-			VFS_HOLD(zfsvfs->z_vfs);
+	if (getzfsvfs(tofs, &zfsvfs) == 0) {
+		if (!mutex_tryenter(&zfsvfs->z_online_recv_lock)) {
+			VFS_RELE(zfsvfs->z_vfs);
+			zfsvfs = NULL;
+			error = EBUSY;
+			goto out;
 		}
-		mutex_exit(&os->os->os_user_ptr_lock);
-
 		/*
 		 * If new properties are supplied, they are to completely
 		 * replace the existing ones, so stash away the existing ones.
 		 */
 		if (props)
-			(void) dsl_prop_get_all(os, &origprops, TRUE);
+			(void) dsl_prop_get_all(zfsvfs->z_os, &origprops, TRUE);
+	} else if (props && dmu_objset_open(tofs, DMU_OST_ANY,
+	    DS_MODE_USER | DS_MODE_READONLY, &os) == 0) {
+		/*
+		 * Get the props even if there was no zfsvfs (zvol or
+		 * unmounted zpl).
+		 */
+		(void) dsl_prop_get_all(os, &origprops, TRUE);
 
 		dmu_objset_close(os);
 	}
@@ -2759,11 +2999,12 @@ zfs_ioc_clear(zfs_cmd_t *zc)
 	/*
 	 * Resume any suspended I/Os.
 	 */
-	zio_resume(spa);
+	if (zio_resume(spa) != 0)
+		error = EIO;
 
 	spa_close(spa, FTAG);
 
-	return (0);
+	return (error);
 }
 
 /*
@@ -2791,6 +3032,120 @@ zfs_ioc_promote(zfs_cmd_t *zc)
 }
 
 /*
+ * Retrieve a single {user|group}{used|quota}@... property.
+ *
+ * inputs:
+ * zc_name	name of filesystem
+ * zc_objset_type zfs_userquota_prop_t
+ * zc_value	domain name (eg. "S-1-234-567-89")
+ * zc_guid	RID/UID/GID
+ *
+ * outputs:
+ * zc_cookie	property value
+ */
+static int
+zfs_ioc_userspace_one(zfs_cmd_t *zc)
+{
+	zfsvfs_t *zfsvfs;
+	int error;
+
+	if (zc->zc_objset_type >= ZFS_NUM_USERQUOTA_PROPS)
+		return (EINVAL);
+
+	error = zfsvfs_hold(zc->zc_name, B_TRUE, FTAG, &zfsvfs);
+	if (error)
+		return (error);
+
+	error = zfs_userspace_one(zfsvfs,
+	    zc->zc_objset_type, zc->zc_value, zc->zc_guid, &zc->zc_cookie);
+	zfsvfs_rele(zfsvfs, FTAG);
+
+	return (error);
+}
+
+/*
+ * inputs:
+ * zc_name		name of filesystem
+ * zc_cookie		zap cursor
+ * zc_objset_type	zfs_userquota_prop_t
+ * zc_nvlist_dst[_size] buffer to fill (not really an nvlist)
+ *
+ * outputs:
+ * zc_nvlist_dst[_size]	data buffer (array of zfs_useracct_t)
+ * zc_cookie	zap cursor
+ */
+static int
+zfs_ioc_userspace_many(zfs_cmd_t *zc)
+{
+	zfsvfs_t *zfsvfs;
+	int error;
+
+	error = zfsvfs_hold(zc->zc_name, B_TRUE, FTAG, &zfsvfs);
+	if (error)
+		return (error);
+
+	int bufsize = zc->zc_nvlist_dst_size;
+	void *buf = kmem_alloc(bufsize, KM_SLEEP);
+
+	error = zfs_userspace_many(zfsvfs, zc->zc_objset_type, &zc->zc_cookie,
+	    buf, &zc->zc_nvlist_dst_size);
+
+	if (error == 0) {
+		error = xcopyout(buf,
+		    (void *)(uintptr_t)zc->zc_nvlist_dst,
+		    zc->zc_nvlist_dst_size);
+	}
+	kmem_free(buf, bufsize);
+	zfsvfs_rele(zfsvfs, FTAG);
+
+	return (error);
+}
+
+/*
+ * inputs:
+ * zc_name		name of filesystem
+ *
+ * outputs:
+ * none
+ */
+static int
+zfs_ioc_userspace_upgrade(zfs_cmd_t *zc)
+{
+	objset_t *os;
+	int error;
+	zfsvfs_t *zfsvfs;
+
+	if (getzfsvfs(zc->zc_name, &zfsvfs) == 0) {
+		if (!dmu_objset_userused_enabled(zfsvfs->z_os->os)) {
+			/*
+			 * If userused is not enabled, it may be because the
+			 * objset needs to be closed & reopened (to grow the
+			 * objset_phys_t).  Suspend/resume the fs will do that.
+			 */
+			int mode;
+			error = zfs_suspend_fs(zfsvfs, NULL, &mode);
+			if (error == 0) {
+				error = zfs_resume_fs(zfsvfs,
+				    zc->zc_name, mode);
+			}
+		}
+		if (error == 0)
+			error = dmu_objset_userspace_upgrade(zfsvfs->z_os);
+		VFS_RELE(zfsvfs->z_vfs);
+	} else {
+		error = dmu_objset_open(zc->zc_name, DMU_OST_ANY,
+		    DS_MODE_USER, &os);
+		if (error)
+			return (error);
+
+		error = dmu_objset_userspace_upgrade(os);
+		dmu_objset_close(os);
+	}
+
+	return (error);
+}
+
+/*
  * We don't want to have a hard dependency
  * against some special symbols in sharefs
  * nfs, and smbsrv.  Determine them if needed when
@@ -2903,7 +3258,7 @@ zfs_ioc_share(zfs_cmd_t *zc)
 		if (error = zsmbexport_fs((void *)
 		    (uintptr_t)zc->zc_share.z_exportdata,
 		    zc->zc_share.z_sharetype == ZFS_SHARE_SMB ?
-		    B_TRUE : B_FALSE)) {
+		    B_TRUE: B_FALSE)) {
 			return (error);
 		}
 		break;
@@ -2924,64 +3279,280 @@ zfs_ioc_share(zfs_cmd_t *zc)
 
 }
 
+ace_t full_access[] = {
+	{(uid_t)-1, ACE_ALL_PERMS, ACE_EVERYONE, 0}
+};
+
+/*
+ * Remove all ACL files in shares dir
+ */
+static int
+zfs_smb_acl_purge(znode_t *dzp)
+{
+	zap_cursor_t	zc;
+	zap_attribute_t	zap;
+	zfsvfs_t *zfsvfs = dzp->z_zfsvfs;
+	int error;
+
+	for (zap_cursor_init(&zc, zfsvfs->z_os, dzp->z_id);
+	    (error = zap_cursor_retrieve(&zc, &zap)) == 0;
+	    zap_cursor_advance(&zc)) {
+		if ((error = VOP_REMOVE(ZTOV(dzp), zap.za_name, kcred,
+		    NULL, 0)) != 0)
+			break;
+	}
+	zap_cursor_fini(&zc);
+	return (error);
+}
+
+static int
+zfs_ioc_smb_acl(zfs_cmd_t *zc)
+{
+	vnode_t *vp;
+	znode_t *dzp;
+	vnode_t *resourcevp = NULL;
+	znode_t *sharedir;
+	zfsvfs_t *zfsvfs;
+	nvlist_t *nvlist;
+	char *src, *target;
+	vattr_t vattr;
+	vsecattr_t vsec;
+	int error = 0;
+
+	if ((error = lookupname(zc->zc_value, UIO_SYSSPACE,
+	    NO_FOLLOW, NULL, &vp)) != 0)
+		return (error);
+
+	/* Now make sure mntpnt and dataset are ZFS */
+
+	if (vp->v_vfsp->vfs_fstype != zfsfstype ||
+	    (strcmp((char *)refstr_value(vp->v_vfsp->vfs_resource),
+	    zc->zc_name) != 0)) {
+		VN_RELE(vp);
+		return (EINVAL);
+	}
+
+	dzp = VTOZ(vp);
+	zfsvfs = dzp->z_zfsvfs;
+	ZFS_ENTER(zfsvfs);
+
+	/*
+	 * Create share dir if its missing.
+	 */
+	mutex_enter(&zfsvfs->z_lock);
+	if (zfsvfs->z_shares_dir == 0) {
+		dmu_tx_t *tx;
+
+		tx = dmu_tx_create(zfsvfs->z_os);
+		dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, TRUE,
+		    ZFS_SHARES_DIR);
+		dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, FALSE, NULL);
+		error = dmu_tx_assign(tx, TXG_WAIT);
+		if (error) {
+			dmu_tx_abort(tx);
+		} else {
+			error = zfs_create_share_dir(zfsvfs, tx);
+			dmu_tx_commit(tx);
+		}
+		if (error) {
+			mutex_exit(&zfsvfs->z_lock);
+			VN_RELE(vp);
+			ZFS_EXIT(zfsvfs);
+			return (error);
+		}
+	}
+	mutex_exit(&zfsvfs->z_lock);
+
+	ASSERT(zfsvfs->z_shares_dir);
+	if ((error = zfs_zget(zfsvfs, zfsvfs->z_shares_dir, &sharedir)) != 0) {
+		VN_RELE(vp);
+		ZFS_EXIT(zfsvfs);
+		return (error);
+	}
+
+	switch (zc->zc_cookie) {
+	case ZFS_SMB_ACL_ADD:
+		vattr.va_mask = AT_MODE|AT_UID|AT_GID|AT_TYPE;
+		vattr.va_type = VREG;
+		vattr.va_mode = S_IFREG|0777;
+		vattr.va_uid = 0;
+		vattr.va_gid = 0;
+
+		vsec.vsa_mask = VSA_ACE;
+		vsec.vsa_aclentp = &full_access;
+		vsec.vsa_aclentsz = sizeof (full_access);
+		vsec.vsa_aclcnt = 1;
+
+		error = VOP_CREATE(ZTOV(sharedir), zc->zc_string,
+		    &vattr, EXCL, 0, &resourcevp, kcred, 0, NULL, &vsec);
+		if (resourcevp)
+			VN_RELE(resourcevp);
+		break;
+
+	case ZFS_SMB_ACL_REMOVE:
+		error = VOP_REMOVE(ZTOV(sharedir), zc->zc_string, kcred,
+		    NULL, 0);
+		break;
+
+	case ZFS_SMB_ACL_RENAME:
+		if ((error = get_nvlist(zc->zc_nvlist_src,
+		    zc->zc_nvlist_src_size, zc->zc_iflags, &nvlist)) != 0) {
+			VN_RELE(vp);
+			ZFS_EXIT(zfsvfs);
+			return (error);
+		}
+		if (nvlist_lookup_string(nvlist, ZFS_SMB_ACL_SRC, &src) ||
+		    nvlist_lookup_string(nvlist, ZFS_SMB_ACL_TARGET,
+		    &target)) {
+			VN_RELE(vp);
+			VN_RELE(ZTOV(sharedir));
+			ZFS_EXIT(zfsvfs);
+			return (error);
+		}
+		error = VOP_RENAME(ZTOV(sharedir), src, ZTOV(sharedir), target,
+		    kcred, NULL, 0);
+		nvlist_free(nvlist);
+		break;
+
+	case ZFS_SMB_ACL_PURGE:
+		error = zfs_smb_acl_purge(sharedir);
+		break;
+
+	default:
+		error = EINVAL;
+		break;
+	}
+
+	VN_RELE(vp);
+	VN_RELE(ZTOV(sharedir));
+
+	ZFS_EXIT(zfsvfs);
+
+	return (error);
+}
+
 /*
  * pool create, destroy, and export don't log the history as part of
  * zfsdev_ioctl, but rather zfs_ioc_pool_create, and zfs_ioc_pool_export
  * do the logging of those commands.
  */
 static zfs_ioc_vec_t zfs_ioc_vec[] = {
-	{ zfs_ioc_pool_create, zfs_secpolicy_config, POOL_NAME, B_FALSE },
-	{ zfs_ioc_pool_destroy,	zfs_secpolicy_config, POOL_NAME, B_FALSE },
-	{ zfs_ioc_pool_import, zfs_secpolicy_config, POOL_NAME, B_TRUE },
-	{ zfs_ioc_pool_export, zfs_secpolicy_config, POOL_NAME, B_FALSE },
-	{ zfs_ioc_pool_configs,	zfs_secpolicy_none, NO_NAME, B_FALSE },
-	{ zfs_ioc_pool_stats, zfs_secpolicy_read, POOL_NAME, B_FALSE },
-	{ zfs_ioc_pool_tryimport, zfs_secpolicy_config, NO_NAME, B_FALSE },
-	{ zfs_ioc_pool_scrub, zfs_secpolicy_config, POOL_NAME, B_TRUE },
-	{ zfs_ioc_pool_freeze, zfs_secpolicy_config, NO_NAME, B_FALSE },
-	{ zfs_ioc_pool_upgrade,	zfs_secpolicy_config, POOL_NAME, B_TRUE },
-	{ zfs_ioc_pool_get_history, zfs_secpolicy_config, POOL_NAME, B_FALSE },
-	{ zfs_ioc_vdev_add, zfs_secpolicy_config, POOL_NAME, B_TRUE },
-	{ zfs_ioc_vdev_remove, zfs_secpolicy_config, POOL_NAME, B_TRUE },
-	{ zfs_ioc_vdev_set_state, zfs_secpolicy_config,	POOL_NAME, B_TRUE },
-	{ zfs_ioc_vdev_attach, zfs_secpolicy_config, POOL_NAME, B_TRUE },
-	{ zfs_ioc_vdev_detach, zfs_secpolicy_config, POOL_NAME, B_TRUE },
-	{ zfs_ioc_vdev_setpath,	zfs_secpolicy_config, POOL_NAME, B_FALSE },
-	{ zfs_ioc_objset_stats,	zfs_secpolicy_read, DATASET_NAME, B_FALSE },
-	{ zfs_ioc_objset_zplprops, zfs_secpolicy_read, DATASET_NAME, B_FALSE },
-	{ zfs_ioc_dataset_list_next, zfs_secpolicy_read,
-	    DATASET_NAME, B_FALSE },
-	{ zfs_ioc_snapshot_list_next, zfs_secpolicy_read,
-	    DATASET_NAME, B_FALSE },
-	{ zfs_ioc_set_prop, zfs_secpolicy_none, DATASET_NAME, B_TRUE },
-	{ zfs_ioc_create_minor,	zfs_secpolicy_minor, DATASET_NAME, B_FALSE },
-	{ zfs_ioc_remove_minor,	zfs_secpolicy_minor, DATASET_NAME, B_FALSE },
-	{ zfs_ioc_create, zfs_secpolicy_create, DATASET_NAME, B_TRUE },
-	{ zfs_ioc_destroy, zfs_secpolicy_destroy, DATASET_NAME, B_TRUE },
-	{ zfs_ioc_rollback, zfs_secpolicy_rollback, DATASET_NAME, B_TRUE },
-	{ zfs_ioc_rename, zfs_secpolicy_rename,	DATASET_NAME, B_TRUE },
-	{ zfs_ioc_recv, zfs_secpolicy_receive, DATASET_NAME, B_TRUE },
-	{ zfs_ioc_send, zfs_secpolicy_send, DATASET_NAME, B_TRUE },
-	{ zfs_ioc_inject_fault,	zfs_secpolicy_inject, NO_NAME, B_FALSE },
-	{ zfs_ioc_clear_fault, zfs_secpolicy_inject, NO_NAME, B_FALSE },
-	{ zfs_ioc_inject_list_next, zfs_secpolicy_inject, NO_NAME, B_FALSE },
-	{ zfs_ioc_error_log, zfs_secpolicy_inject, POOL_NAME, B_FALSE },
-	{ zfs_ioc_clear, zfs_secpolicy_config, POOL_NAME, B_TRUE },
-	{ zfs_ioc_promote, zfs_secpolicy_promote, DATASET_NAME, B_TRUE },
-	{ zfs_ioc_destroy_snaps, zfs_secpolicy_destroy,	DATASET_NAME, B_TRUE },
-	{ zfs_ioc_snapshot, zfs_secpolicy_snapshot, DATASET_NAME, B_TRUE },
-	{ zfs_ioc_dsobj_to_dsname, zfs_secpolicy_config, POOL_NAME, B_FALSE },
-	{ zfs_ioc_obj_to_path, zfs_secpolicy_config, NO_NAME, B_FALSE },
-	{ zfs_ioc_pool_set_props, zfs_secpolicy_config,	POOL_NAME, B_TRUE },
-	{ zfs_ioc_pool_get_props, zfs_secpolicy_read, POOL_NAME, B_FALSE },
-	{ zfs_ioc_set_fsacl, zfs_secpolicy_fsacl, DATASET_NAME, B_TRUE },
-	{ zfs_ioc_get_fsacl, zfs_secpolicy_read, DATASET_NAME, B_FALSE },
-	{ zfs_ioc_iscsi_perm_check, zfs_secpolicy_iscsi,
-	    DATASET_NAME, B_FALSE },
-	{ zfs_ioc_share, zfs_secpolicy_share, DATASET_NAME, B_FALSE },
-	{ zfs_ioc_inherit_prop, zfs_secpolicy_inherit, DATASET_NAME, B_TRUE },
+	{ zfs_ioc_pool_create, zfs_secpolicy_config, POOL_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_pool_destroy,	zfs_secpolicy_config, POOL_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_pool_import, zfs_secpolicy_config, POOL_NAME, B_TRUE,
+	    B_FALSE },
+	{ zfs_ioc_pool_export, zfs_secpolicy_config, POOL_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_pool_configs,	zfs_secpolicy_none, NO_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_pool_stats, zfs_secpolicy_read, POOL_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_pool_tryimport, zfs_secpolicy_config, NO_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_pool_scrub, zfs_secpolicy_config, POOL_NAME, B_TRUE,
+	    B_TRUE },
+	{ zfs_ioc_pool_freeze, zfs_secpolicy_config, NO_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_pool_upgrade,	zfs_secpolicy_config, POOL_NAME, B_TRUE,
+	    B_TRUE },
+	{ zfs_ioc_pool_get_history, zfs_secpolicy_config, POOL_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_vdev_add, zfs_secpolicy_config, POOL_NAME, B_TRUE,
+	    B_TRUE },
+	{ zfs_ioc_vdev_remove, zfs_secpolicy_config, POOL_NAME, B_TRUE,
+	    B_TRUE },
+	{ zfs_ioc_vdev_set_state, zfs_secpolicy_config,	POOL_NAME, B_TRUE,
+	    B_FALSE },
+	{ zfs_ioc_vdev_attach, zfs_secpolicy_config, POOL_NAME, B_TRUE,
+	    B_TRUE },
+	{ zfs_ioc_vdev_detach, zfs_secpolicy_config, POOL_NAME, B_TRUE,
+	    B_TRUE },
+	{ zfs_ioc_vdev_setpath,	zfs_secpolicy_config, POOL_NAME, B_FALSE,
+	    B_TRUE },
+	{ zfs_ioc_vdev_setfru,	zfs_secpolicy_config, POOL_NAME, B_FALSE,
+	    B_TRUE },
+	{ zfs_ioc_objset_stats,	zfs_secpolicy_read, DATASET_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_objset_zplprops, zfs_secpolicy_read, DATASET_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_dataset_list_next, zfs_secpolicy_read, DATASET_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_snapshot_list_next, zfs_secpolicy_read, DATASET_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_set_prop, zfs_secpolicy_none, DATASET_NAME, B_TRUE, B_TRUE },
+	{ zfs_ioc_create_minor,	zfs_secpolicy_minor, DATASET_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_remove_minor,	zfs_secpolicy_minor, DATASET_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_create, zfs_secpolicy_create, DATASET_NAME, B_TRUE, B_TRUE },
+	{ zfs_ioc_destroy, zfs_secpolicy_destroy, DATASET_NAME, B_TRUE,
+	    B_TRUE},
+	{ zfs_ioc_rollback, zfs_secpolicy_rollback, DATASET_NAME, B_TRUE,
+	    B_TRUE },
+	{ zfs_ioc_rename, zfs_secpolicy_rename,	DATASET_NAME, B_TRUE, B_TRUE },
+	{ zfs_ioc_recv, zfs_secpolicy_receive, DATASET_NAME, B_TRUE, B_TRUE },
+	{ zfs_ioc_send, zfs_secpolicy_send, DATASET_NAME, B_TRUE, B_FALSE },
+	{ zfs_ioc_inject_fault,	zfs_secpolicy_inject, NO_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_clear_fault, zfs_secpolicy_inject, NO_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_inject_list_next, zfs_secpolicy_inject, NO_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_error_log, zfs_secpolicy_inject, POOL_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_clear, zfs_secpolicy_config, POOL_NAME, B_TRUE, B_FALSE },
+	{ zfs_ioc_promote, zfs_secpolicy_promote, DATASET_NAME, B_TRUE,
+	    B_TRUE },
+	{ zfs_ioc_destroy_snaps, zfs_secpolicy_destroy,	DATASET_NAME, B_TRUE,
+	    B_TRUE },
+	{ zfs_ioc_snapshot, zfs_secpolicy_snapshot, DATASET_NAME, B_TRUE,
+	    B_TRUE },
+	{ zfs_ioc_dsobj_to_dsname, zfs_secpolicy_config, POOL_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_obj_to_path, zfs_secpolicy_config, NO_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_pool_set_props, zfs_secpolicy_config,	POOL_NAME, B_TRUE,
+	    B_TRUE },
+	{ zfs_ioc_pool_get_props, zfs_secpolicy_read, POOL_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_set_fsacl, zfs_secpolicy_fsacl, DATASET_NAME, B_TRUE,
+	    B_TRUE },
+	{ zfs_ioc_get_fsacl, zfs_secpolicy_read, DATASET_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_iscsi_perm_check, zfs_secpolicy_iscsi, DATASET_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_share, zfs_secpolicy_share, DATASET_NAME, B_FALSE, B_FALSE },
+	{ zfs_ioc_inherit_prop, zfs_secpolicy_inherit, DATASET_NAME, B_TRUE,
+	    B_TRUE },
+	{ zfs_ioc_smb_acl, zfs_secpolicy_smb_acl, DATASET_NAME, B_FALSE,
+	    B_FALSE },
+	{ zfs_ioc_userspace_one, zfs_secpolicy_userspace_one,
+	    DATASET_NAME, B_FALSE, B_FALSE },
+	{ zfs_ioc_userspace_many, zfs_secpolicy_userspace_many,
+	    DATASET_NAME, B_FALSE, B_FALSE },
+	{ zfs_ioc_userspace_upgrade, zfs_secpolicy_userspace_upgrade,
+	    DATASET_NAME, B_FALSE, B_TRUE },
 };
 
+int
+pool_status_check(const char *name, zfs_ioc_namecheck_t type)
+{
+	spa_t *spa;
+	int error;
+
+	ASSERT(type == POOL_NAME || type == DATASET_NAME);
+
+	error = spa_open(name, &spa, FTAG);
+	if (error == 0) {
+		if (spa_suspended(spa))
+			error = EAGAIN;
+		spa_close(spa, FTAG);
+	}
+	return (error);
+}
+
 static int
 zfsdev_ioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *cr, int *rvalp)
 {
@@ -3000,7 +3571,7 @@ zfsdev_ioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *cr, int *rvalp)
 
 	zc = kmem_zalloc(sizeof (zfs_cmd_t), KM_SLEEP);
 
-	error = xcopyin((void *)arg, zc, sizeof (zfs_cmd_t));
+	error = ddi_copyin((void *)arg, zc, sizeof (zfs_cmd_t), flag);
 
 	if (error == 0)
 		error = zfs_ioc_vec[vec].zvec_secpolicy(zc, cr);
@@ -3011,15 +3582,22 @@ zfsdev_ioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *cr, int *rvalp)
 	 */
 	if (error == 0) {
 		zc->zc_name[sizeof (zc->zc_name) - 1] = '\0';
+		zc->zc_iflags = flag & FKIOCTL;
 		switch (zfs_ioc_vec[vec].zvec_namecheck) {
 		case POOL_NAME:
 			if (pool_namecheck(zc->zc_name, NULL, NULL) != 0)
 				error = EINVAL;
+			if (zfs_ioc_vec[vec].zvec_pool_check)
+				error = pool_status_check(zc->zc_name,
+				    zfs_ioc_vec[vec].zvec_namecheck);
 			break;
 
 		case DATASET_NAME:
 			if (dataset_namecheck(zc->zc_name, NULL, NULL) != 0)
 				error = EINVAL;
+			if (zfs_ioc_vec[vec].zvec_pool_check)
+				error = pool_status_check(zc->zc_name,
+				    zfs_ioc_vec[vec].zvec_namecheck);
 			break;
 
 		case NO_NAME:
@@ -3030,10 +3608,10 @@ zfsdev_ioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *cr, int *rvalp)
 	if (error == 0)
 		error = zfs_ioc_vec[vec].zvec_func(zc);
 
-	rc = xcopyout(zc, (void *)arg, sizeof (zfs_cmd_t));
+	rc = ddi_copyout(zc, (void *)arg, sizeof (zfs_cmd_t), flag);
 	if (error == 0) {
 		error = rc;
-		if (zfs_ioc_vec[vec].zvec_his_log == B_TRUE)
+		if (zfs_ioc_vec[vec].zvec_his_log)
 			zfs_log_history(zc);
 	}
 
diff --git a/module/zfs/zfs_log.c b/module/zfs/zfs_log.c
index 84d64b4df..3f0b6b0ed 100644
--- a/module/zfs/zfs_log.c
+++ b/module/zfs/zfs_log.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -467,9 +467,6 @@ zfs_log_rename(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
  */
 ssize_t zfs_immediate_write_sz = 32768;
 
-#define	ZIL_MAX_LOG_DATA (SPA_MAXBLOCKSIZE - sizeof (zil_trailer_t) - \
-    sizeof (lr_write_t))
-
 void
 zfs_log_write(zilog_t *zilog, dmu_tx_t *tx, int txtype,
 	znode_t *zp, offset_t off, ssize_t resid, int ioflag)
@@ -483,29 +480,6 @@ zfs_log_write(zilog_t *zilog, dmu_tx_t *tx, int txtype,
 
 	ZFS_HANDLE_REPLAY(zilog, tx); /* exits if replay */
 
-	/*
-	 * Writes are handled in three different ways:
-	 *
-	 * WR_INDIRECT:
-	 *    In this mode, if we need to commit the write later, then the block
-	 *    is immediately written into the file system (using dmu_sync),
-	 *    and a pointer to the block is put into the log record.
-	 *    When the txg commits the block is linked in.
-	 *    This saves additionally writing the data into the log record.
-	 *    There are a few requirements for this to occur:
-	 *	- write is greater than zfs_immediate_write_sz
-	 *	- not using slogs (as slogs are assumed to always be faster
-	 *	  than writing into the main pool)
-	 *	- the write occupies only one block
-	 * WR_COPIED:
-	 *    If we know we'll immediately be committing the
-	 *    transaction (FSYNC or FDSYNC), the we allocate a larger
-	 *    log record here for the data and copy the data in.
-	 * WR_NEED_COPY:
-	 *    Otherwise we don't allocate a buffer, and *if* we need to
-	 *    flush the write later then a buffer is allocated and
-	 *    we retrieve the data using the dmu.
-	 */
 	slogging = spa_has_slogs(zilog->zl_spa);
 	if (resid > zfs_immediate_write_sz && !slogging && resid <= zp->z_blksz)
 		write_state = WR_INDIRECT;
@@ -535,7 +509,7 @@ zfs_log_write(zilog_t *zilog, dmu_tx_t *tx, int txtype,
 		    (write_state == WR_COPIED ? len : 0));
 		lr = (lr_write_t *)&itx->itx_lr;
 		if (write_state == WR_COPIED && dmu_read(zp->z_zfsvfs->z_os,
-		    zp->z_id, off, len, lr + 1) != 0) {
+		    zp->z_id, off, len, lr + 1, DMU_READ_NO_PREFETCH) != 0) {
 			kmem_free(itx, offsetof(itx_t, itx_lr) +
 			    itx->itx_lr.lrc_reclen);
 			itx = zil_itx_create(txtype, sizeof (*lr));
diff --git a/module/zfs/zfs_vfsops.c b/module/zfs/zfs_vfsops.c
index 1bf1bc527..8a859b575 100644
--- a/module/zfs/zfs_vfsops.c
+++ b/module/zfs/zfs_vfsops.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -67,6 +67,8 @@ static major_t zfs_major;
 static minor_t zfs_minor;
 static kmutex_t	zfs_dev_mtx;
 
+extern int sys_shutdown;
+
 static int zfs_mount(vfs_t *vfsp, vnode_t *mvp, struct mounta *uap, cred_t *cr);
 static int zfs_umount(vfs_t *vfsp, int fflag, cred_t *cr);
 static int zfs_mountroot(vfs_t *vfsp, enum whymountroot);
@@ -145,12 +147,24 @@ zfs_sync(vfs_t *vfsp, short flag, cred_t *cr)
 		 * Sync a specific filesystem.
 		 */
 		zfsvfs_t *zfsvfs = vfsp->vfs_data;
+		dsl_pool_t *dp;
 
 		ZFS_ENTER(zfsvfs);
+		dp = dmu_objset_pool(zfsvfs->z_os);
+
+		/*
+		 * If the system is shutting down, then skip any
+		 * filesystems which may exist on a suspended pool.
+		 */
+		if (sys_shutdown && spa_suspended(dp->dp_spa)) {
+			ZFS_EXIT(zfsvfs);
+			return (0);
+		}
+
 		if (zfsvfs->z_log != NULL)
 			zil_commit(zfsvfs->z_log, UINT64_MAX, 0);
 		else
-			txg_wait_synced(dmu_objset_pool(zfsvfs->z_os), 0);
+			txg_wait_synced(dp, 0);
 		ZFS_EXIT(zfsvfs);
 	} else {
 		/*
@@ -554,6 +568,393 @@ unregister:
 
 }
 
+static void
+uidacct(objset_t *os, boolean_t isgroup, uint64_t fuid,
+    int64_t delta, dmu_tx_t *tx)
+{
+	uint64_t used = 0;
+	char buf[32];
+	int err;
+	uint64_t obj = isgroup ? DMU_GROUPUSED_OBJECT : DMU_USERUSED_OBJECT;
+
+	if (delta == 0)
+		return;
+
+	(void) snprintf(buf, sizeof (buf), "%llx", (longlong_t)fuid);
+	err = zap_lookup(os, obj, buf, 8, 1, &used);
+	ASSERT(err == 0 || err == ENOENT);
+	/* no underflow/overflow */
+	ASSERT(delta > 0 || used >= -delta);
+	ASSERT(delta < 0 || used + delta > used);
+	used += delta;
+	if (used == 0)
+		err = zap_remove(os, obj, buf, tx);
+	else
+		err = zap_update(os, obj, buf, 8, 1, &used, tx);
+	ASSERT(err == 0);
+}
+
+static void
+zfs_space_delta_cb(objset_t *os, dmu_object_type_t bonustype,
+    void *oldbonus, void *newbonus,
+    uint64_t oldused, uint64_t newused, dmu_tx_t *tx)
+{
+	znode_phys_t *oldznp = oldbonus;
+	znode_phys_t *newznp = newbonus;
+
+	if (bonustype != DMU_OT_ZNODE)
+		return;
+
+	/* We charge 512 for the dnode (if it's allocated). */
+	if (oldznp->zp_gen != 0)
+		oldused += DNODE_SIZE;
+	if (newznp->zp_gen != 0)
+		newused += DNODE_SIZE;
+
+	if (oldznp->zp_uid == newznp->zp_uid) {
+		uidacct(os, B_FALSE, oldznp->zp_uid, newused-oldused, tx);
+	} else {
+		uidacct(os, B_FALSE, oldznp->zp_uid, -oldused, tx);
+		uidacct(os, B_FALSE, newznp->zp_uid, newused, tx);
+	}
+
+	if (oldznp->zp_gid == newznp->zp_gid) {
+		uidacct(os, B_TRUE, oldznp->zp_gid, newused-oldused, tx);
+	} else {
+		uidacct(os, B_TRUE, oldznp->zp_gid, -oldused, tx);
+		uidacct(os, B_TRUE, newznp->zp_gid, newused, tx);
+	}
+}
+
+static void
+fuidstr_to_sid(zfsvfs_t *zfsvfs, const char *fuidstr,
+    char *domainbuf, int buflen, uid_t *ridp)
+{
+	extern uint64_t strtonum(const char *str, char **nptr);
+	uint64_t fuid;
+	const char *domain;
+
+	fuid = strtonum(fuidstr, NULL);
+
+	domain = zfs_fuid_find_by_idx(zfsvfs, FUID_INDEX(fuid));
+	if (domain)
+		(void) strlcpy(domainbuf, domain, buflen);
+	else
+		domainbuf[0] = '\0';
+	*ridp = FUID_RID(fuid);
+}
+
+static uint64_t
+zfs_userquota_prop_to_obj(zfsvfs_t *zfsvfs, zfs_userquota_prop_t type)
+{
+	switch (type) {
+	case ZFS_PROP_USERUSED:
+		return (DMU_USERUSED_OBJECT);
+	case ZFS_PROP_GROUPUSED:
+		return (DMU_GROUPUSED_OBJECT);
+	case ZFS_PROP_USERQUOTA:
+		return (zfsvfs->z_userquota_obj);
+	case ZFS_PROP_GROUPQUOTA:
+		return (zfsvfs->z_groupquota_obj);
+	}
+	return (0);
+}
+
+int
+zfs_userspace_many(zfsvfs_t *zfsvfs, zfs_userquota_prop_t type,
+    uint64_t *cookiep, void *vbuf, uint64_t *bufsizep)
+{
+	int error;
+	zap_cursor_t zc;
+	zap_attribute_t za;
+	zfs_useracct_t *buf = vbuf;
+	uint64_t obj;
+
+	if (!dmu_objset_userspace_present(zfsvfs->z_os))
+		return (ENOTSUP);
+
+	obj = zfs_userquota_prop_to_obj(zfsvfs, type);
+	if (obj == 0) {
+		*bufsizep = 0;
+		return (0);
+	}
+
+	for (zap_cursor_init_serialized(&zc, zfsvfs->z_os, obj, *cookiep);
+	    (error = zap_cursor_retrieve(&zc, &za)) == 0;
+	    zap_cursor_advance(&zc)) {
+		if ((uintptr_t)buf - (uintptr_t)vbuf + sizeof (zfs_useracct_t) >
+		    *bufsizep)
+			break;
+
+		fuidstr_to_sid(zfsvfs, za.za_name,
+		    buf->zu_domain, sizeof (buf->zu_domain), &buf->zu_rid);
+
+		buf->zu_space = za.za_first_integer;
+		buf++;
+	}
+	if (error == ENOENT)
+		error = 0;
+
+	ASSERT3U((uintptr_t)buf - (uintptr_t)vbuf, <=, *bufsizep);
+	*bufsizep = (uintptr_t)buf - (uintptr_t)vbuf;
+	*cookiep = zap_cursor_serialize(&zc);
+	zap_cursor_fini(&zc);
+	return (error);
+}
+
+/*
+ * buf must be big enough (eg, 32 bytes)
+ */
+static int
+id_to_fuidstr(zfsvfs_t *zfsvfs, const char *domain, uid_t rid,
+    char *buf, boolean_t addok)
+{
+	uint64_t fuid;
+	int domainid = 0;
+
+	if (domain && domain[0]) {
+		domainid = zfs_fuid_find_by_domain(zfsvfs, domain, NULL, addok);
+		if (domainid == -1)
+			return (ENOENT);
+	}
+	fuid = FUID_ENCODE(domainid, rid);
+	(void) sprintf(buf, "%llx", (longlong_t)fuid);
+	return (0);
+}
+
+int
+zfs_userspace_one(zfsvfs_t *zfsvfs, zfs_userquota_prop_t type,
+    const char *domain, uint64_t rid, uint64_t *valp)
+{
+	char buf[32];
+	int err;
+	uint64_t obj;
+
+	*valp = 0;
+
+	if (!dmu_objset_userspace_present(zfsvfs->z_os))
+		return (ENOTSUP);
+
+	obj = zfs_userquota_prop_to_obj(zfsvfs, type);
+	if (obj == 0)
+		return (0);
+
+	err = id_to_fuidstr(zfsvfs, domain, rid, buf, B_FALSE);
+	if (err)
+		return (err);
+
+	err = zap_lookup(zfsvfs->z_os, obj, buf, 8, 1, valp);
+	if (err == ENOENT)
+		err = 0;
+	return (err);
+}
+
+int
+zfs_set_userquota(zfsvfs_t *zfsvfs, zfs_userquota_prop_t type,
+    const char *domain, uint64_t rid, uint64_t quota)
+{
+	char buf[32];
+	int err;
+	dmu_tx_t *tx;
+	uint64_t *objp;
+	boolean_t fuid_dirtied;
+
+	if (type != ZFS_PROP_USERQUOTA && type != ZFS_PROP_GROUPQUOTA)
+		return (EINVAL);
+
+	if (zfsvfs->z_version < ZPL_VERSION_USERSPACE)
+		return (ENOTSUP);
+
+	objp = (type == ZFS_PROP_USERQUOTA) ? &zfsvfs->z_userquota_obj :
+	    &zfsvfs->z_groupquota_obj;
+
+	err = id_to_fuidstr(zfsvfs, domain, rid, buf, B_TRUE);
+	if (err)
+		return (err);
+	fuid_dirtied = zfsvfs->z_fuid_dirty;
+
+	tx = dmu_tx_create(zfsvfs->z_os);
+	dmu_tx_hold_zap(tx, *objp ? *objp : DMU_NEW_OBJECT, B_TRUE, NULL);
+	if (*objp == 0) {
+		dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, B_TRUE,
+		    zfs_userquota_prop_prefixes[type]);
+	}
+	if (fuid_dirtied)
+		zfs_fuid_txhold(zfsvfs, tx);
+	err = dmu_tx_assign(tx, TXG_WAIT);
+	if (err) {
+		dmu_tx_abort(tx);
+		return (err);
+	}
+
+	mutex_enter(&zfsvfs->z_lock);
+	if (*objp == 0) {
+		*objp = zap_create(zfsvfs->z_os, DMU_OT_USERGROUP_QUOTA,
+		    DMU_OT_NONE, 0, tx);
+		VERIFY(0 == zap_add(zfsvfs->z_os, MASTER_NODE_OBJ,
+		    zfs_userquota_prop_prefixes[type], 8, 1, objp, tx));
+	}
+	mutex_exit(&zfsvfs->z_lock);
+
+	if (quota == 0) {
+		err = zap_remove(zfsvfs->z_os, *objp, buf, tx);
+		if (err == ENOENT)
+			err = 0;
+	} else {
+		err = zap_update(zfsvfs->z_os, *objp, buf, 8, 1, &quota, tx);
+	}
+	ASSERT(err == 0);
+	if (fuid_dirtied)
+		zfs_fuid_sync(zfsvfs, tx);
+	dmu_tx_commit(tx);
+	return (err);
+}
+
+boolean_t
+zfs_usergroup_overquota(zfsvfs_t *zfsvfs, boolean_t isgroup, uint64_t fuid)
+{
+	char buf[32];
+	uint64_t used, quota, usedobj, quotaobj;
+	int err;
+
+	usedobj = isgroup ? DMU_GROUPUSED_OBJECT : DMU_USERUSED_OBJECT;
+	quotaobj = isgroup ? zfsvfs->z_groupquota_obj : zfsvfs->z_userquota_obj;
+
+	if (quotaobj == 0 || zfsvfs->z_replay)
+		return (B_FALSE);
+
+	(void) sprintf(buf, "%llx", (longlong_t)fuid);
+	err = zap_lookup(zfsvfs->z_os, quotaobj, buf, 8, 1, &quota);
+	if (err != 0)
+		return (B_FALSE);
+
+	err = zap_lookup(zfsvfs->z_os, usedobj, buf, 8, 1, &used);
+	if (err != 0)
+		return (B_FALSE);
+	return (used >= quota);
+}
+
+int
+zfsvfs_create(const char *osname, int mode, zfsvfs_t **zvp)
+{
+	objset_t *os;
+	zfsvfs_t *zfsvfs;
+	uint64_t zval;
+	int i, error;
+
+	if (error = dsl_prop_get_integer(osname, "readonly", &zval, NULL))
+		return (error);
+	if (zval)
+		mode |= DS_MODE_READONLY;
+
+	error = dmu_objset_open(osname, DMU_OST_ZFS, mode, &os);
+	if (error == EROFS) {
+		mode |= DS_MODE_READONLY;
+		error = dmu_objset_open(osname, DMU_OST_ZFS, mode, &os);
+	}
+	if (error)
+		return (error);
+
+	/*
+	 * Initialize the zfs-specific filesystem structure.
+	 * Should probably make this a kmem cache, shuffle fields,
+	 * and just bzero up to z_hold_mtx[].
+	 */
+	zfsvfs = kmem_zalloc(sizeof (zfsvfs_t), KM_SLEEP);
+	zfsvfs->z_vfs = NULL;
+	zfsvfs->z_parent = zfsvfs;
+	zfsvfs->z_max_blksz = SPA_MAXBLOCKSIZE;
+	zfsvfs->z_show_ctldir = ZFS_SNAPDIR_VISIBLE;
+	zfsvfs->z_os = os;
+
+	error = zfs_get_zplprop(os, ZFS_PROP_VERSION, &zfsvfs->z_version);
+	if (error) {
+		goto out;
+	} else if (zfsvfs->z_version > ZPL_VERSION) {
+		(void) printf("Mismatched versions:  File system "
+		    "is version %llu on-disk format, which is "
+		    "incompatible with this software version %lld!",
+		    (u_longlong_t)zfsvfs->z_version, ZPL_VERSION);
+		error = ENOTSUP;
+		goto out;
+	}
+
+	if ((error = zfs_get_zplprop(os, ZFS_PROP_NORMALIZE, &zval)) != 0)
+		goto out;
+	zfsvfs->z_norm = (int)zval;
+
+	if ((error = zfs_get_zplprop(os, ZFS_PROP_UTF8ONLY, &zval)) != 0)
+		goto out;
+	zfsvfs->z_utf8 = (zval != 0);
+
+	if ((error = zfs_get_zplprop(os, ZFS_PROP_CASE, &zval)) != 0)
+		goto out;
+	zfsvfs->z_case = (uint_t)zval;
+
+	/*
+	 * Fold case on file systems that are always or sometimes case
+	 * insensitive.
+	 */
+	if (zfsvfs->z_case == ZFS_CASE_INSENSITIVE ||
+	    zfsvfs->z_case == ZFS_CASE_MIXED)
+		zfsvfs->z_norm |= U8_TEXTPREP_TOUPPER;
+
+	zfsvfs->z_use_fuids = USE_FUIDS(zfsvfs->z_version, zfsvfs->z_os);
+
+	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_ROOT_OBJ, 8, 1,
+	    &zfsvfs->z_root);
+	if (error)
+		goto out;
+	ASSERT(zfsvfs->z_root != 0);
+
+	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_UNLINKED_SET, 8, 1,
+	    &zfsvfs->z_unlinkedobj);
+	if (error)
+		goto out;
+
+	error = zap_lookup(os, MASTER_NODE_OBJ,
+	    zfs_userquota_prop_prefixes[ZFS_PROP_USERQUOTA],
+	    8, 1, &zfsvfs->z_userquota_obj);
+	if (error && error != ENOENT)
+		goto out;
+
+	error = zap_lookup(os, MASTER_NODE_OBJ,
+	    zfs_userquota_prop_prefixes[ZFS_PROP_GROUPQUOTA],
+	    8, 1, &zfsvfs->z_groupquota_obj);
+	if (error && error != ENOENT)
+		goto out;
+
+	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_FUID_TABLES, 8, 1,
+	    &zfsvfs->z_fuid_obj);
+	if (error && error != ENOENT)
+		goto out;
+
+	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_SHARES_DIR, 8, 1,
+	    &zfsvfs->z_shares_dir);
+	if (error && error != ENOENT)
+		goto out;
+
+	mutex_init(&zfsvfs->z_znodes_lock, NULL, MUTEX_DEFAULT, NULL);
+	mutex_init(&zfsvfs->z_online_recv_lock, NULL, MUTEX_DEFAULT, NULL);
+	mutex_init(&zfsvfs->z_lock, NULL, MUTEX_DEFAULT, NULL);
+	list_create(&zfsvfs->z_all_znodes, sizeof (znode_t),
+	    offsetof(znode_t, z_link_node));
+	rrw_init(&zfsvfs->z_teardown_lock);
+	rw_init(&zfsvfs->z_teardown_inactive_lock, NULL, RW_DEFAULT, NULL);
+	rw_init(&zfsvfs->z_fuid_lock, NULL, RW_DEFAULT, NULL);
+	for (i = 0; i != ZFS_OBJ_MTX_SZ; i++)
+		mutex_init(&zfsvfs->z_hold_mtx[i], NULL, MUTEX_DEFAULT, NULL);
+
+	*zvp = zfsvfs;
+	return (0);
+
+out:
+	dmu_objset_close(os);
+	*zvp = NULL;
+	kmem_free(zfsvfs, sizeof (zfsvfs_t));
+	return (error);
+}
+
 static int
 zfsvfs_setup(zfsvfs_t *zfsvfs, boolean_t mounting)
 {
@@ -570,6 +971,12 @@ zfsvfs_setup(zfsvfs_t *zfsvfs, boolean_t mounting)
 	dmu_objset_set_user(zfsvfs->z_os, zfsvfs);
 	mutex_exit(&zfsvfs->z_os->os->os_user_ptr_lock);
 
+	zfsvfs->z_log = zil_open(zfsvfs->z_os, zfs_get_data);
+	if (zil_disable) {
+		zil_destroy(zfsvfs->z_log, 0);
+		zfsvfs->z_log = NULL;
+	}
+
 	/*
 	 * If we are not mounting (ie: online recv), then we don't
 	 * have to worry about replaying the log as we blocked all
@@ -588,11 +995,7 @@ zfsvfs_setup(zfsvfs_t *zfsvfs, boolean_t mounting)
 		else
 			zfs_unlinked_drain(zfsvfs);
 
-		zfsvfs->z_log = zil_open(zfsvfs->z_os, zfs_get_data);
-		if (zil_disable) {
-			zil_destroy(zfsvfs->z_log, 0);
-			zfsvfs->z_log = NULL;
-		} else {
+		if (zfsvfs->z_log) {
 			/*
 			 * Parse and replay the intent log.
 			 *
@@ -630,49 +1033,63 @@ zfsvfs_setup(zfsvfs_t *zfsvfs, boolean_t mounting)
 	return (0);
 }
 
-static void
-zfs_freezfsvfs(zfsvfs_t *zfsvfs)
+void
+zfsvfs_free(zfsvfs_t *zfsvfs)
 {
+	int i;
+	extern krwlock_t zfsvfs_lock; /* in zfs_znode.c */
+
+	/*
+	 * This is a barrier to prevent the filesystem from going away in
+	 * zfs_znode_move() until we can safely ensure that the filesystem is
+	 * not unmounted. We consider the filesystem valid before the barrier
+	 * and invalid after the barrier.
+	 */
+	rw_enter(&zfsvfs_lock, RW_READER);
+	rw_exit(&zfsvfs_lock);
+
+	zfs_fuid_destroy(zfsvfs);
+
 	mutex_destroy(&zfsvfs->z_znodes_lock);
 	mutex_destroy(&zfsvfs->z_online_recv_lock);
+	mutex_destroy(&zfsvfs->z_lock);
 	list_destroy(&zfsvfs->z_all_znodes);
 	rrw_destroy(&zfsvfs->z_teardown_lock);
 	rw_destroy(&zfsvfs->z_teardown_inactive_lock);
 	rw_destroy(&zfsvfs->z_fuid_lock);
+	for (i = 0; i != ZFS_OBJ_MTX_SZ; i++)
+		mutex_destroy(&zfsvfs->z_hold_mtx[i]);
 	kmem_free(zfsvfs, sizeof (zfsvfs_t));
 }
 
+static void
+zfs_set_fuid_feature(zfsvfs_t *zfsvfs)
+{
+	zfsvfs->z_use_fuids = USE_FUIDS(zfsvfs->z_version, zfsvfs->z_os);
+	if (zfsvfs->z_use_fuids && zfsvfs->z_vfs) {
+		vfs_set_feature(zfsvfs->z_vfs, VFSFT_XVATTR);
+		vfs_set_feature(zfsvfs->z_vfs, VFSFT_SYSATTR_VIEWS);
+		vfs_set_feature(zfsvfs->z_vfs, VFSFT_ACEMASKONACCESS);
+		vfs_set_feature(zfsvfs->z_vfs, VFSFT_ACLONCREATE);
+		vfs_set_feature(zfsvfs->z_vfs, VFSFT_ACCESS_FILTER);
+	}
+}
+
 static int
 zfs_domount(vfs_t *vfsp, char *osname)
 {
 	dev_t mount_dev;
-	uint64_t recordsize, readonly;
+	uint64_t recordsize, fsid_guid;
 	int error = 0;
-	int mode;
 	zfsvfs_t *zfsvfs;
-	znode_t *zp = NULL;
 
 	ASSERT(vfsp);
 	ASSERT(osname);
 
-	/*
-	 * Initialize the zfs-specific filesystem structure.
-	 * Should probably make this a kmem cache, shuffle fields,
-	 * and just bzero up to z_hold_mtx[].
-	 */
-	zfsvfs = kmem_zalloc(sizeof (zfsvfs_t), KM_SLEEP);
+	error = zfsvfs_create(osname, DS_MODE_OWNER, &zfsvfs);
+	if (error)
+		return (error);
 	zfsvfs->z_vfs = vfsp;
-	zfsvfs->z_parent = zfsvfs;
-	zfsvfs->z_max_blksz = SPA_MAXBLOCKSIZE;
-	zfsvfs->z_show_ctldir = ZFS_SNAPDIR_VISIBLE;
-
-	mutex_init(&zfsvfs->z_znodes_lock, NULL, MUTEX_DEFAULT, NULL);
-	mutex_init(&zfsvfs->z_online_recv_lock, NULL, MUTEX_DEFAULT, NULL);
-	list_create(&zfsvfs->z_all_znodes, sizeof (znode_t),
-	    offsetof(znode_t, z_link_node));
-	rrw_init(&zfsvfs->z_teardown_lock);
-	rw_init(&zfsvfs->z_teardown_inactive_lock, NULL, RW_DEFAULT, NULL);
-	rw_init(&zfsvfs->z_fuid_lock, NULL, RW_DEFAULT, NULL);
 
 	/* Initialize the generic filesystem structure. */
 	vfsp->vfs_bcount = 0;
@@ -694,39 +1111,24 @@ zfs_domount(vfs_t *vfsp, char *osname)
 	vfsp->vfs_flag |= VFS_NOTRUNC;
 	vfsp->vfs_data = zfsvfs;
 
-	if (error = dsl_prop_get_integer(osname, "readonly", &readonly, NULL))
-		goto out;
-
-	mode = DS_MODE_OWNER;
-	if (readonly)
-		mode |= DS_MODE_READONLY;
-
-	error = dmu_objset_open(osname, DMU_OST_ZFS, mode, &zfsvfs->z_os);
-	if (error == EROFS) {
-		mode = DS_MODE_OWNER | DS_MODE_READONLY;
-		error = dmu_objset_open(osname, DMU_OST_ZFS, mode,
-		    &zfsvfs->z_os);
-	}
-
-	if (error)
-		goto out;
-
-	if (error = zfs_init_fs(zfsvfs, &zp))
-		goto out;
-
-	/* The call to zfs_init_fs leaves the vnode held, release it here. */
-	VN_RELE(ZTOV(zp));
+	/*
+	 * The fsid is 64 bits, composed of an 8-bit fs type, which
+	 * separates our fsid from any other filesystem types, and a
+	 * 56-bit objset unique ID.  The objset unique ID is unique to
+	 * all objsets open on this system, provided by unique_create().
+	 * The 8-bit fs type must be put in the low bits of fsid[1]
+	 * because that's where other Solaris filesystems put it.
+	 */
+	fsid_guid = dmu_objset_fsid_guid(zfsvfs->z_os);
+	ASSERT((fsid_guid & ~((1ULL<<56)-1)) == 0);
+	vfsp->vfs_fsid.val[0] = fsid_guid;
+	vfsp->vfs_fsid.val[1] = ((fsid_guid>>32) << 8) |
+	    zfsfstype & 0xFF;
 
 	/*
 	 * Set features for file system.
 	 */
-	zfsvfs->z_use_fuids = USE_FUIDS(zfsvfs->z_version, zfsvfs->z_os);
-	if (zfsvfs->z_use_fuids) {
-		vfs_set_feature(vfsp, VFSFT_XVATTR);
-		vfs_set_feature(vfsp, VFSFT_SYSATTR_VIEWS);
-		vfs_set_feature(vfsp, VFSFT_ACEMASKONACCESS);
-		vfs_set_feature(vfsp, VFSFT_ACLONCREATE);
-	}
+	zfs_set_fuid_feature(zfsvfs);
 	if (zfsvfs->z_case == ZFS_CASE_INSENSITIVE) {
 		vfs_set_feature(vfsp, VFSFT_DIRENTFLAGS);
 		vfs_set_feature(vfsp, VFSFT_CASEINSENSITIVE);
@@ -739,13 +1141,16 @@ zfs_domount(vfs_t *vfsp, char *osname)
 	if (dmu_objset_is_snapshot(zfsvfs->z_os)) {
 		uint64_t pval;
 
-		ASSERT(mode & DS_MODE_READONLY);
 		atime_changed_cb(zfsvfs, B_FALSE);
 		readonly_changed_cb(zfsvfs, B_TRUE);
 		if (error = dsl_prop_get_integer(osname, "xattr", &pval, NULL))
 			goto out;
 		xattr_changed_cb(zfsvfs, pval);
 		zfsvfs->z_issnap = B_TRUE;
+
+		mutex_enter(&zfsvfs->z_os->os->os_user_ptr_lock);
+		dmu_objset_set_user(zfsvfs->z_os, zfsvfs);
+		mutex_exit(&zfsvfs->z_os->os->os_user_ptr_lock);
 	} else {
 		error = zfsvfs_setup(zfsvfs, B_TRUE);
 	}
@@ -754,9 +1159,8 @@ zfs_domount(vfs_t *vfsp, char *osname)
 		zfsctl_create(zfsvfs);
 out:
 	if (error) {
-		if (zfsvfs->z_os)
-			dmu_objset_close(zfsvfs->z_os);
-		zfs_freezfsvfs(zfsvfs);
+		dmu_objset_close(zfsvfs->z_os);
+		zfsvfs_free(zfsvfs);
 	} else {
 		atomic_add_32(&zfs_active_fs_count, 1);
 	}
@@ -1067,6 +1471,13 @@ zfs_mount(vfs_t *vfsp, vnode_t *mvp, struct mounta *uap, cred_t *cr)
 
 	error = zfs_domount(vfsp, osname);
 
+	/*
+	 * Add an extra VFS_HOLD on our parent vfs so that it can't
+	 * disappear due to a forced unmount.
+	 */
+	if (error == 0 && ((zfsvfs_t *)vfsp->vfs_data)->z_issnap)
+		VFS_HOLD(mvp->v_vfsp);
+
 out:
 	pn_free(&spn);
 	return (error);
@@ -1426,15 +1837,16 @@ zfs_vget(vfs_t *vfsp, vnode_t **vpp, fid_t *fidp)
  * 'z_teardown_inactive_lock' write held.
  */
 int
-zfs_suspend_fs(zfsvfs_t *zfsvfs, char *name, int *mode)
+zfs_suspend_fs(zfsvfs_t *zfsvfs, char *name, int *modep)
 {
 	int error;
 
 	if ((error = zfsvfs_teardown(zfsvfs, B_FALSE)) != 0)
 		return (error);
 
-	*mode = zfsvfs->z_os->os_mode;
-	dmu_objset_name(zfsvfs->z_os, name);
+	*modep = zfsvfs->z_os->os_mode;
+	if (name)
+		dmu_objset_name(zfsvfs->z_os, name);
 	dmu_objset_close(zfsvfs->z_os);
 
 	return (0);
@@ -1493,13 +1905,15 @@ static void
 zfs_freevfs(vfs_t *vfsp)
 {
 	zfsvfs_t *zfsvfs = vfsp->vfs_data;
-	int i;
 
-	for (i = 0; i != ZFS_OBJ_MTX_SZ; i++)
-		mutex_destroy(&zfsvfs->z_hold_mtx[i]);
+	/*
+	 * If this is a snapshot, we have an extra VFS_HOLD on our parent
+	 * from zfs_mount().  Release it here.
+	 */
+	if (zfsvfs->z_issnap)
+		VFS_RELE(zfsvfs->z_parent->z_vfs);
 
-	zfs_fuid_destroy(zfsvfs);
-	zfs_freezfsvfs(zfsvfs);
+	zfsvfs_free(zfsvfs);
 
 	atomic_add_32(&zfs_active_fs_count, -1);
 }
@@ -1558,6 +1972,8 @@ zfs_init(void)
 	 * Initialize znode cache, vnode ops, etc...
 	 */
 	zfs_znode_init();
+
+	dmu_objset_register_type(DMU_OST_ZFS, zfs_space_delta_cb);
 }
 
 void
@@ -1574,54 +1990,46 @@ zfs_busy(void)
 }
 
 int
-zfs_set_version(const char *name, uint64_t newvers)
+zfs_set_version(zfsvfs_t *zfsvfs, uint64_t newvers)
 {
 	int error;
-	objset_t *os;
+	objset_t *os = zfsvfs->z_os;
 	dmu_tx_t *tx;
-	uint64_t curvers;
-
-	/*
-	 * XXX for now, require that the filesystem be unmounted.  Would
-	 * be nice to find the zfsvfs_t and just update that if
-	 * possible.
-	 */
 
 	if (newvers < ZPL_VERSION_INITIAL || newvers > ZPL_VERSION)
 		return (EINVAL);
 
-	error = dmu_objset_open(name, DMU_OST_ZFS, DS_MODE_OWNER, &os);
-	if (error)
-		return (error);
-
-	error = zap_lookup(os, MASTER_NODE_OBJ, ZPL_VERSION_STR,
-	    8, 1, &curvers);
-	if (error)
-		goto out;
-	if (newvers < curvers) {
-		error = EINVAL;
-		goto out;
-	}
+	if (newvers < zfsvfs->z_version)
+		return (EINVAL);
 
 	tx = dmu_tx_create(os);
-	dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, 0, ZPL_VERSION_STR);
+	dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, B_FALSE, ZPL_VERSION_STR);
 	error = dmu_tx_assign(tx, TXG_WAIT);
 	if (error) {
 		dmu_tx_abort(tx);
-		goto out;
+		return (error);
+	}
+	error = zap_update(os, MASTER_NODE_OBJ, ZPL_VERSION_STR,
+	    8, 1, &newvers, tx);
+
+	if (error) {
+		dmu_tx_commit(tx);
+		return (error);
 	}
-	error = zap_update(os, MASTER_NODE_OBJ, ZPL_VERSION_STR, 8, 1,
-	    &newvers, tx);
 
 	spa_history_internal_log(LOG_DS_UPGRADE,
 	    dmu_objset_spa(os), tx, CRED(),
-	    "oldver=%llu newver=%llu dataset = %llu", curvers, newvers,
-	    dmu_objset_id(os));
+	    "oldver=%llu newver=%llu dataset = %llu",
+	    zfsvfs->z_version, newvers, dmu_objset_id(os));
+
 	dmu_tx_commit(tx);
 
-out:
-	dmu_objset_close(os);
-	return (error);
+	zfsvfs->z_version = newvers;
+
+	if (zfsvfs->z_version >= ZPL_VERSION_FUID)
+		zfs_set_fuid_feature(zfsvfs);
+
+	return (0);
 }
 
 /*
diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c
index e38abb28c..88d4e52c1 100644
--- a/module/zfs/zfs_vnops.c
+++ b/module/zfs/zfs_vnops.c
@@ -101,6 +101,7 @@
  *	pushing cached pages (which acquires range locks) and syncing out
  *	cached atime changes.  Third, zfs_zinactive() may require a new tx,
  *	which could deadlock the system if you were already holding one.
+ *	If you must call VN_RELE() within a tx then use VN_RELE_ASYNC().
  *
  *  (3)	All range locks must be grabbed before calling dmu_tx_assign(),
  *	as they can span dmu_tx_assign() calls.
@@ -363,7 +364,8 @@ update_pages(vnode_t *vp, int64_t start, int len, objset_t *os, uint64_t oid)
 			caddr_t va;
 
 			va = zfs_map_page(pp, S_WRITE);
-			(void) dmu_read(os, oid, start+off, nbytes, va+off);
+			(void) dmu_read(os, oid, start+off, nbytes, va+off,
+			    DMU_READ_PREFETCH);
 			zfs_unmap_page(pp, va);
 			page_unlock(pp);
 		}
@@ -567,6 +569,7 @@ zfs_write(vnode_t *vp, uio_t *uio, int ioflag, cred_t *cr, caller_context_t *ct)
 	int		max_blksz = zfsvfs->z_max_blksz;
 	uint64_t	pflags;
 	int		error;
+	arc_buf_t	*abuf;
 
 	/*
 	 * Fasttrack empty write
@@ -663,10 +666,46 @@ zfs_write(vnode_t *vp, uio_t *uio, int ioflag, cred_t *cr, caller_context_t *ct)
 	 * and allows us to do more fine-grained space accounting.
 	 */
 	while (n > 0) {
+		abuf = NULL;
+		woff = uio->uio_loffset;
+
+again:
+		if (zfs_usergroup_overquota(zfsvfs,
+		    B_FALSE, zp->z_phys->zp_uid) ||
+		    zfs_usergroup_overquota(zfsvfs,
+		    B_TRUE, zp->z_phys->zp_gid)) {
+			if (abuf != NULL)
+				dmu_return_arcbuf(abuf);
+			error = EDQUOT;
+			break;
+		}
+
+		/*
+		 * If dmu_assign_arcbuf() is expected to execute with minimum
+		 * overhead loan an arc buffer and copy user data to it before
+		 * we enter a txg.  This avoids holding a txg forever while we
+		 * pagefault on a hanging NFS server mapping.
+		 */
+		if (abuf == NULL && n >= max_blksz &&
+		    woff >= zp->z_phys->zp_size &&
+		    P2PHASE(woff, max_blksz) == 0 &&
+		    zp->z_blksz == max_blksz) {
+			size_t cbytes;
+
+			abuf = dmu_request_arcbuf(zp->z_dbuf, max_blksz);
+			ASSERT(abuf != NULL);
+			ASSERT(arc_buf_size(abuf) == max_blksz);
+			if (error = uiocopy(abuf->b_data, max_blksz,
+			    UIO_WRITE, uio, &cbytes)) {
+				dmu_return_arcbuf(abuf);
+				break;
+			}
+			ASSERT(cbytes == max_blksz);
+		}
+
 		/*
 		 * Start a transaction.
 		 */
-		woff = uio->uio_loffset;
 		tx = dmu_tx_create(zfsvfs->z_os);
 		dmu_tx_hold_bonus(tx, zp->z_id);
 		dmu_tx_hold_write(tx, zp->z_id, woff, MIN(n, max_blksz));
@@ -675,9 +714,11 @@ zfs_write(vnode_t *vp, uio_t *uio, int ioflag, cred_t *cr, caller_context_t *ct)
 			if (error == ERESTART) {
 				dmu_tx_wait(tx);
 				dmu_tx_abort(tx);
-				continue;
+				goto again;
 			}
 			dmu_tx_abort(tx);
+			if (abuf != NULL)
+				dmu_return_arcbuf(abuf);
 			break;
 		}
 
@@ -706,12 +747,22 @@ zfs_write(vnode_t *vp, uio_t *uio, int ioflag, cred_t *cr, caller_context_t *ct)
 		 */
 		nbytes = MIN(n, max_blksz - P2PHASE(woff, max_blksz));
 
-		tx_bytes = uio->uio_resid;
-		error = dmu_write_uio(zfsvfs->z_os, zp->z_id, uio, nbytes, tx);
-		tx_bytes -= uio->uio_resid;
-		if (tx_bytes && vn_has_cached_data(vp))
+		if (abuf == NULL) {
+			tx_bytes = uio->uio_resid;
+			error = dmu_write_uio(zfsvfs->z_os, zp->z_id, uio,
+			    nbytes, tx);
+			tx_bytes -= uio->uio_resid;
+		} else {
+			tx_bytes = nbytes;
+			ASSERT(tx_bytes == max_blksz);
+			dmu_assign_arcbuf(zp->z_dbuf, woff, abuf, tx);
+			ASSERT(tx_bytes <= uio->uio_resid);
+			uioskip(uio, tx_bytes);
+		}
+		if (tx_bytes && vn_has_cached_data(vp)) {
 			update_pages(vp, woff,
 			    tx_bytes, zfsvfs->z_os, zp->z_id);
+		}
 
 		/*
 		 * If we made no progress, we're done.  If we made even
@@ -791,10 +842,15 @@ zfs_get_done(dmu_buf_t *db, void *vzgd)
 	zgd_t *zgd = (zgd_t *)vzgd;
 	rl_t *rl = zgd->zgd_rl;
 	vnode_t *vp = ZTOV(rl->r_zp);
+	objset_t *os = rl->r_zp->z_zfsvfs->z_os;
 
 	dmu_buf_rele(db, vzgd);
 	zfs_range_unlock(rl);
-	VN_RELE(vp);
+	/*
+	 * Release the vnode asynchronously as we currently have the
+	 * txg stopped from syncing.
+	 */
+	VN_RELE_ASYNC(vp, dsl_pool_vnrele_taskq(dmu_objset_pool(os)));
 	zil_add_block(zgd->zgd_zilog, zgd->zgd_bp);
 	kmem_free(zgd, sizeof (zgd_t));
 }
@@ -824,7 +880,12 @@ zfs_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio)
 	if (zfs_zget(zfsvfs, lr->lr_foid, &zp) != 0)
 		return (ENOENT);
 	if (zp->z_unlinked) {
-		VN_RELE(ZTOV(zp));
+		/*
+		 * Release the vnode asynchronously as we currently have the
+		 * txg stopped from syncing.
+		 */
+		VN_RELE_ASYNC(ZTOV(zp),
+		    dsl_pool_vnrele_taskq(dmu_objset_pool(os)));
 		return (ENOENT);
 	}
 
@@ -842,7 +903,8 @@ zfs_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio)
 			error = ENOENT;
 			goto out;
 		}
-		VERIFY(0 == dmu_read(os, lr->lr_foid, off, dlen, buf));
+		VERIFY(0 == dmu_read(os, lr->lr_foid, off, dlen, buf,
+		    DMU_READ_NO_PREFETCH));
 	} else { /* indirect write */
 		uint64_t boff; /* block starting offset */
 
@@ -896,7 +958,11 @@ zfs_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio)
 	}
 out:
 	zfs_range_unlock(rl);
-	VN_RELE(ZTOV(zp));
+	/*
+	 * Release the vnode asynchronously as we currently have the
+	 * txg stopped from syncing.
+	 */
+	VN_RELE_ASYNC(ZTOV(zp), dsl_pool_vnrele_taskq(dmu_objset_pool(os)));
 	return (error);
 }
 
@@ -1074,11 +1140,11 @@ zfs_create(vnode_t *dvp, char *name, vattr_t *vap, vcexcl_t excl,
 	zfs_dirlock_t	*dl;
 	dmu_tx_t	*tx;
 	int		error;
-	zfs_acl_t	*aclp = NULL;
-	zfs_fuid_info_t *fuidp = NULL;
 	ksid_t		*ksid;
 	uid_t		uid;
 	gid_t		gid = crgetgid(cr);
+	zfs_acl_ids_t	acl_ids;
+	boolean_t	fuid_dirtied;
 
 	/*
 	 * If we have an ephemeral id, ACL, or XVATTR then
@@ -1141,21 +1207,9 @@ top:
 			if (strcmp(name, "..") == 0)
 				error = EISDIR;
 			ZFS_EXIT(zfsvfs);
-			if (aclp)
-				zfs_acl_free(aclp);
 			return (error);
 		}
 	}
-	if (vsecp && aclp == NULL) {
-		error = zfs_vsec_2_aclp(zfsvfs, vap->va_type, vsecp, &aclp);
-		if (error) {
-			ZFS_EXIT(zfsvfs);
-			if (dl)
-				zfs_dirent_unlock(dl);
-			return (error);
-		}
-	}
-
 	if (zp == NULL) {
 		uint64_t txtype;
 
@@ -1177,30 +1231,28 @@ top:
 			goto out;
 		}
 
+		if ((error = zfs_acl_ids_create(dzp, 0, vap, cr, vsecp,
+		    &acl_ids)) != 0)
+			goto out;
+		if (zfs_acl_ids_overquota(zfsvfs, &acl_ids)) {
+			error = EDQUOT;
+			goto out;
+		}
+
 		tx = dmu_tx_create(os);
 		dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
-		if ((aclp && aclp->z_has_fuids) || IS_EPHEMERAL(uid) ||
-		    IS_EPHEMERAL(gid)) {
-			if (zfsvfs->z_fuid_obj == 0) {
-				dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
-				dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0,
-				    FUID_SIZE_ESTIMATE(zfsvfs));
-				dmu_tx_hold_zap(tx, MASTER_NODE_OBJ,
-				    FALSE, NULL);
-			} else {
-				dmu_tx_hold_bonus(tx, zfsvfs->z_fuid_obj);
-				dmu_tx_hold_write(tx, zfsvfs->z_fuid_obj, 0,
-				    FUID_SIZE_ESTIMATE(zfsvfs));
-			}
-		}
+		fuid_dirtied = zfsvfs->z_fuid_dirty;
+		if (fuid_dirtied)
+			zfs_fuid_txhold(zfsvfs, tx);
 		dmu_tx_hold_bonus(tx, dzp->z_id);
 		dmu_tx_hold_zap(tx, dzp->z_id, TRUE, name);
-		if ((dzp->z_phys->zp_flags & ZFS_INHERIT_ACE) || aclp) {
+		if (acl_ids.z_aclp->z_acl_bytes > ZFS_ACE_SPACE) {
 			dmu_tx_hold_write(tx, DMU_NEW_OBJECT,
 			    0, SPA_MAXBLOCKSIZE);
 		}
 		error = dmu_tx_assign(tx, TXG_NOWAIT);
 		if (error) {
+			zfs_acl_ids_free(&acl_ids);
 			zfs_dirent_unlock(dl);
 			if (error == ERESTART) {
 				dmu_tx_wait(tx);
@@ -1209,19 +1261,21 @@ top:
 			}
 			dmu_tx_abort(tx);
 			ZFS_EXIT(zfsvfs);
-			if (aclp)
-				zfs_acl_free(aclp);
 			return (error);
 		}
-		zfs_mknode(dzp, vap, tx, cr, 0, &zp, 0, aclp, &fuidp);
+		zfs_mknode(dzp, vap, tx, cr, 0, &zp, 0, &acl_ids);
+
+		if (fuid_dirtied)
+			zfs_fuid_sync(zfsvfs, tx);
+
 		(void) zfs_link_create(dl, zp, tx, ZNEW);
+
 		txtype = zfs_log_create_txtype(Z_FILE, vsecp, vap);
 		if (flag & FIGNORECASE)
 			txtype |= TX_CI;
 		zfs_log_create(zilog, tx, txtype, dzp, zp, name,
-		    vsecp, fuidp, vap);
-		if (fuidp)
-			zfs_fuid_info_free(fuidp);
+		    vsecp, acl_ids.z_fuidp, vap);
+		zfs_acl_ids_free(&acl_ids);
 		dmu_tx_commit(tx);
 	} else {
 		int aflags = (flag & FAPPEND) ? V_APPEND : 0;
@@ -1292,8 +1346,6 @@ out:
 			*vpp = svp;
 		}
 	}
-	if (aclp)
-		zfs_acl_free(aclp);
 
 	ZFS_EXIT(zfsvfs);
 	return (error);
@@ -1528,12 +1580,12 @@ zfs_mkdir(vnode_t *dvp, char *dirname, vattr_t *vap, vnode_t **vpp, cred_t *cr,
 	uint64_t	txtype;
 	dmu_tx_t	*tx;
 	int		error;
-	zfs_acl_t	*aclp = NULL;
-	zfs_fuid_info_t	*fuidp = NULL;
 	int		zf = ZNEW;
 	ksid_t		*ksid;
 	uid_t		uid;
 	gid_t		gid = crgetgid(cr);
+	zfs_acl_ids_t	acl_ids;
+	boolean_t	fuid_dirtied;
 
 	ASSERT(vap->va_type == VDIR);
 
@@ -1594,38 +1646,33 @@ top:
 		return (error);
 	}
 
-	if (vsecp && aclp == NULL) {
-		error = zfs_vsec_2_aclp(zfsvfs, vap->va_type, vsecp, &aclp);
-		if (error) {
-			zfs_dirent_unlock(dl);
-			ZFS_EXIT(zfsvfs);
-			return (error);
-		}
+	if ((error = zfs_acl_ids_create(dzp, 0, vap, cr, vsecp,
+	    &acl_ids)) != 0) {
+		zfs_dirent_unlock(dl);
+		ZFS_EXIT(zfsvfs);
+		return (error);
 	}
+	if (zfs_acl_ids_overquota(zfsvfs, &acl_ids)) {
+		zfs_dirent_unlock(dl);
+		ZFS_EXIT(zfsvfs);
+		return (EDQUOT);
+	}
+
 	/*
 	 * Add a new entry to the directory.
 	 */
 	tx = dmu_tx_create(zfsvfs->z_os);
 	dmu_tx_hold_zap(tx, dzp->z_id, TRUE, dirname);
 	dmu_tx_hold_zap(tx, DMU_NEW_OBJECT, FALSE, NULL);
-	if ((aclp && aclp->z_has_fuids) || IS_EPHEMERAL(uid) ||
-	    IS_EPHEMERAL(gid)) {
-		if (zfsvfs->z_fuid_obj == 0) {
-			dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
-			dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0,
-			    FUID_SIZE_ESTIMATE(zfsvfs));
-			dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, FALSE, NULL);
-		} else {
-			dmu_tx_hold_bonus(tx, zfsvfs->z_fuid_obj);
-			dmu_tx_hold_write(tx, zfsvfs->z_fuid_obj, 0,
-			    FUID_SIZE_ESTIMATE(zfsvfs));
-		}
-	}
-	if ((dzp->z_phys->zp_flags & ZFS_INHERIT_ACE) || aclp)
+	fuid_dirtied = zfsvfs->z_fuid_dirty;
+	if (fuid_dirtied)
+		zfs_fuid_txhold(zfsvfs, tx);
+	if (acl_ids.z_aclp->z_acl_bytes > ZFS_ACE_SPACE)
 		dmu_tx_hold_write(tx, DMU_NEW_OBJECT,
 		    0, SPA_MAXBLOCKSIZE);
 	error = dmu_tx_assign(tx, TXG_NOWAIT);
 	if (error) {
+		zfs_acl_ids_free(&acl_ids);
 		zfs_dirent_unlock(dl);
 		if (error == ERESTART) {
 			dmu_tx_wait(tx);
@@ -1634,19 +1681,16 @@ top:
 		}
 		dmu_tx_abort(tx);
 		ZFS_EXIT(zfsvfs);
-		if (aclp)
-			zfs_acl_free(aclp);
 		return (error);
 	}
 
 	/*
 	 * Create new node.
 	 */
-	zfs_mknode(dzp, vap, tx, cr, 0, &zp, 0, aclp, &fuidp);
-
-	if (aclp)
-		zfs_acl_free(aclp);
+	zfs_mknode(dzp, vap, tx, cr, 0, &zp, 0, &acl_ids);
 
+	if (fuid_dirtied)
+		zfs_fuid_sync(zfsvfs, tx);
 	/*
 	 * Now put new name in parent dir.
 	 */
@@ -1657,10 +1701,10 @@ top:
 	txtype = zfs_log_create_txtype(Z_DIR, vsecp, vap);
 	if (flags & FIGNORECASE)
 		txtype |= TX_CI;
-	zfs_log_create(zilog, tx, txtype, dzp, zp, dirname, vsecp, fuidp, vap);
+	zfs_log_create(zilog, tx, txtype, dzp, zp, dirname, vsecp,
+	    acl_ids.z_fuidp, vap);
 
-	if (fuidp)
-		zfs_fuid_info_free(fuidp);
+	zfs_acl_ids_free(&acl_ids);
 	dmu_tx_commit(tx);
 
 	zfs_dirent_unlock(dl);
@@ -1969,6 +2013,21 @@ zfs_readdir(vnode_t *vp, uio_t *uio, cred_t *cr, int *eofp,
 			}
 		}
 
+		if (flags & V_RDDIR_ACCFILTER) {
+			/*
+			 * If we have no access at all, don't include
+			 * this entry in the returned information
+			 */
+			znode_t	*ezp;
+			if (zfs_zget(zp->z_zfsvfs, objnum, &ezp) != 0)
+				goto skip_entry;
+			if (!zfs_has_access(ezp, cr)) {
+				VN_RELE(ZTOV(ezp));
+				goto skip_entry;
+			}
+			VN_RELE(ZTOV(ezp));
+		}
+
 		if (flags & V_RDDIR_ENTFLAGS)
 			reclen = EDIRENT_RECLEN(strlen(zap.za_name));
 		else
@@ -2020,6 +2079,7 @@ zfs_readdir(vnode_t *vp, uio_t *uio, cred_t *cr, int *eofp,
 		if (prefetch)
 			dmu_prefetch(os, objnum, 0, 0);
 
+	skip_entry:
 		/*
 		 * Move to the next entry, fill in the previous offset.
 		 */
@@ -2120,8 +2180,6 @@ zfs_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
 	ZFS_VERIFY_ZP(zp);
 	pzp = zp->z_phys;
 
-	mutex_enter(&zp->z_lock);
-
 	/*
 	 * If ACL is trivial don't bother looking for ACE_READ_ATTRIBUTES.
 	 * Also, if we are the owner don't bother, since owner should
@@ -2131,7 +2189,6 @@ zfs_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
 	    (pzp->zp_uid != crgetuid(cr))) {
 		if (error = zfs_zaccess(zp, ACE_READ_ATTRIBUTES, 0,
 		    skipaclchk, cr)) {
-			mutex_exit(&zp->z_lock);
 			ZFS_EXIT(zfsvfs);
 			return (error);
 		}
@@ -2142,6 +2199,7 @@ zfs_getattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
 	 * than to determine whether we were asked the question.
 	 */
 
+	mutex_enter(&zp->z_lock);
 	vap->va_type = vp->v_type;
 	vap->va_mode = pzp->zp_mode & MODEMASK;
 	zfs_fuid_map_ids(zp, cr, &vap->va_uid, &vap->va_gid);
@@ -2312,6 +2370,7 @@ zfs_setattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
 	uint_t		saved_mask;
 	int		trim_mask = 0;
 	uint64_t	new_mode;
+	uint64_t	new_uid, new_gid;
 	znode_t		*attrzp;
 	int		need_policy = FALSE;
 	int		err;
@@ -2320,6 +2379,7 @@ zfs_setattr(vnode_t *vp, vattr_t *vap, int flags, cred_t *cr,
 	xoptattr_t	*xoap;
 	zfs_acl_t	*aclp = NULL;
 	boolean_t skipaclchk = (flags & ATTR_NOACLCHECK) ? B_TRUE : B_FALSE;
+	boolean_t fuid_dirtied = B_FALSE;
 
 	if (mask == 0)
 		return (0);
@@ -2610,30 +2670,14 @@ top:
 
 	tx = dmu_tx_create(zfsvfs->z_os);
 	dmu_tx_hold_bonus(tx, zp->z_id);
-	if (((mask & AT_UID) && IS_EPHEMERAL(vap->va_uid)) ||
-	    ((mask & AT_GID) && IS_EPHEMERAL(vap->va_gid))) {
-		if (zfsvfs->z_fuid_obj == 0) {
-			dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
-			dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0,
-			    FUID_SIZE_ESTIMATE(zfsvfs));
-			dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, FALSE, NULL);
-		} else {
-			dmu_tx_hold_bonus(tx, zfsvfs->z_fuid_obj);
-			dmu_tx_hold_write(tx, zfsvfs->z_fuid_obj, 0,
-			    FUID_SIZE_ESTIMATE(zfsvfs));
-		}
-	}
 
 	if (mask & AT_MODE) {
 		uint64_t pmode = pzp->zp_mode;
 
 		new_mode = (pmode & S_IFMT) | (vap->va_mode & ~S_IFMT);
 
-		if (err = zfs_acl_chmod_setattr(zp, &aclp, new_mode)) {
-			dmu_tx_abort(tx);
-			ZFS_EXIT(zfsvfs);
-			return (err);
-		}
+		if (err = zfs_acl_chmod_setattr(zp, &aclp, new_mode))
+			goto out;
 		if (pzp->zp_acl.z_acl_extern_obj) {
 			/* Are we upgrading ACL from old V0 format to new V1 */
 			if (zfsvfs->z_version <= ZPL_VERSION_FUID &&
@@ -2655,36 +2699,53 @@ top:
 		}
 	}
 
-	if ((mask & (AT_UID | AT_GID)) && pzp->zp_xattr != 0) {
-		err = zfs_zget(zp->z_zfsvfs, pzp->zp_xattr, &attrzp);
-		if (err) {
-			dmu_tx_abort(tx);
-			ZFS_EXIT(zfsvfs);
-			if (aclp)
-				zfs_acl_free(aclp);
-			return (err);
+	if (mask & (AT_UID | AT_GID)) {
+		if (pzp->zp_xattr) {
+			err = zfs_zget(zp->z_zfsvfs, pzp->zp_xattr, &attrzp);
+			if (err)
+				goto out;
+			dmu_tx_hold_bonus(tx, attrzp->z_id);
+		}
+		if (mask & AT_UID) {
+			new_uid = zfs_fuid_create(zfsvfs,
+			    (uint64_t)vap->va_uid, cr, ZFS_OWNER, &fuidp);
+			if (new_uid != pzp->zp_uid &&
+			    zfs_usergroup_overquota(zfsvfs, B_FALSE, new_uid)) {
+				err = EDQUOT;
+				goto out;
+			}
+		}
+
+		if (mask & AT_GID) {
+			new_gid = zfs_fuid_create(zfsvfs, (uint64_t)vap->va_gid,
+			    cr, ZFS_GROUP, &fuidp);
+			if (new_gid != pzp->zp_gid &&
+			    zfs_usergroup_overquota(zfsvfs, B_TRUE, new_gid)) {
+				err = EDQUOT;
+				goto out;
+			}
+		}
+		fuid_dirtied = zfsvfs->z_fuid_dirty;
+		if (fuid_dirtied) {
+			if (zfsvfs->z_fuid_obj == 0) {
+				dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
+				dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0,
+				    FUID_SIZE_ESTIMATE(zfsvfs));
+				dmu_tx_hold_zap(tx, MASTER_NODE_OBJ,
+				    FALSE, NULL);
+			} else {
+				dmu_tx_hold_bonus(tx, zfsvfs->z_fuid_obj);
+				dmu_tx_hold_write(tx, zfsvfs->z_fuid_obj, 0,
+				    FUID_SIZE_ESTIMATE(zfsvfs));
+			}
 		}
-		dmu_tx_hold_bonus(tx, attrzp->z_id);
 	}
 
 	err = dmu_tx_assign(tx, TXG_NOWAIT);
 	if (err) {
-		if (attrzp)
-			VN_RELE(ZTOV(attrzp));
-
-		if (aclp) {
-			zfs_acl_free(aclp);
-			aclp = NULL;
-		}
-
-		if (err == ERESTART) {
+		if (err == ERESTART)
 			dmu_tx_wait(tx);
-			dmu_tx_abort(tx);
-			goto top;
-		}
-		dmu_tx_abort(tx);
-		ZFS_EXIT(zfsvfs);
-		return (err);
+		goto out;
 	}
 
 	dmu_buf_will_dirty(zp->z_dbuf, tx);
@@ -2702,7 +2763,7 @@ top:
 	if (mask & AT_MODE) {
 		mutex_enter(&zp->z_acl_lock);
 		zp->z_phys->zp_mode = new_mode;
-		err = zfs_aclset_common(zp, aclp, cr, &fuidp, tx);
+		err = zfs_aclset_common(zp, aclp, cr, tx);
 		ASSERT3U(err, ==, 0);
 		mutex_exit(&zp->z_acl_lock);
 	}
@@ -2711,25 +2772,17 @@ top:
 		mutex_enter(&attrzp->z_lock);
 
 	if (mask & AT_UID) {
-		pzp->zp_uid = zfs_fuid_create(zfsvfs,
-		    vap->va_uid, cr, ZFS_OWNER, tx, &fuidp);
-		if (attrzp) {
-			attrzp->z_phys->zp_uid = zfs_fuid_create(zfsvfs,
-			    vap->va_uid,  cr, ZFS_OWNER, tx, &fuidp);
-		}
+		pzp->zp_uid = new_uid;
+		if (attrzp)
+			attrzp->z_phys->zp_uid = new_uid;
 	}
 
 	if (mask & AT_GID) {
-		pzp->zp_gid = zfs_fuid_create(zfsvfs, vap->va_gid,
-		    cr, ZFS_GROUP, tx, &fuidp);
+		pzp->zp_gid = new_gid;
 		if (attrzp)
-			attrzp->z_phys->zp_gid = zfs_fuid_create(zfsvfs,
-			    vap->va_gid, cr, ZFS_GROUP, tx, &fuidp);
+			attrzp->z_phys->zp_gid = new_gid;
 	}
 
-	if (aclp)
-		zfs_acl_free(aclp);
-
 	if (attrzp)
 		mutex_exit(&attrzp->z_lock);
 
@@ -2791,17 +2844,35 @@ top:
 		zfs_xvattr_set(zp, xvap);
 	}
 
+	if (fuid_dirtied)
+		zfs_fuid_sync(zfsvfs, tx);
+
 	if (mask != 0)
 		zfs_log_setattr(zilog, tx, TX_SETATTR, zp, vap, mask, fuidp);
 
-	if (fuidp)
-		zfs_fuid_info_free(fuidp);
 	mutex_exit(&zp->z_lock);
 
+out:
 	if (attrzp)
 		VN_RELE(ZTOV(attrzp));
 
-	dmu_tx_commit(tx);
+	if (aclp) {
+		zfs_acl_free(aclp);
+		aclp = NULL;
+	}
+
+	if (fuidp) {
+		zfs_fuid_info_free(fuidp);
+		fuidp = NULL;
+	}
+
+	if (err)
+		dmu_tx_abort(tx);
+	else
+		dmu_tx_commit(tx);
+
+	if (err == ERESTART)
+		goto top;
 
 	ZFS_EXIT(zfsvfs);
 	return (err);
@@ -3232,7 +3303,8 @@ zfs_symlink(vnode_t *dvp, char *name, vattr_t *vap, char *link, cred_t *cr,
 	int		len = strlen(link);
 	int		error;
 	int		zflg = ZNEW;
-	zfs_fuid_info_t *fuidp = NULL;
+	zfs_acl_ids_t	acl_ids;
+	boolean_t	fuid_dirtied;
 
 	ASSERT(vap->va_type == VLNK);
 
@@ -3267,26 +3339,25 @@ top:
 		return (error);
 	}
 
+	VERIFY(0 == zfs_acl_ids_create(dzp, 0, vap, cr, NULL, &acl_ids));
+	if (zfs_acl_ids_overquota(zfsvfs, &acl_ids)) {
+		zfs_acl_ids_free(&acl_ids);
+		zfs_dirent_unlock(dl);
+		ZFS_EXIT(zfsvfs);
+		return (EDQUOT);
+	}
 	tx = dmu_tx_create(zfsvfs->z_os);
+	fuid_dirtied = zfsvfs->z_fuid_dirty;
 	dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0, MAX(1, len));
 	dmu_tx_hold_bonus(tx, dzp->z_id);
 	dmu_tx_hold_zap(tx, dzp->z_id, TRUE, name);
-	if (dzp->z_phys->zp_flags & ZFS_INHERIT_ACE)
+	if (acl_ids.z_aclp->z_acl_bytes > ZFS_ACE_SPACE)
 		dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0, SPA_MAXBLOCKSIZE);
-	if (IS_EPHEMERAL(crgetuid(cr)) || IS_EPHEMERAL(crgetgid(cr))) {
-		if (zfsvfs->z_fuid_obj == 0) {
-			dmu_tx_hold_bonus(tx, DMU_NEW_OBJECT);
-			dmu_tx_hold_write(tx, DMU_NEW_OBJECT, 0,
-			    FUID_SIZE_ESTIMATE(zfsvfs));
-			dmu_tx_hold_zap(tx, MASTER_NODE_OBJ, FALSE, NULL);
-		} else {
-			dmu_tx_hold_bonus(tx, zfsvfs->z_fuid_obj);
-			dmu_tx_hold_write(tx, zfsvfs->z_fuid_obj, 0,
-			    FUID_SIZE_ESTIMATE(zfsvfs));
-		}
-	}
+	if (fuid_dirtied)
+		zfs_fuid_txhold(zfsvfs, tx);
 	error = dmu_tx_assign(tx, TXG_NOWAIT);
 	if (error) {
+		zfs_acl_ids_free(&acl_ids);
 		zfs_dirent_unlock(dl);
 		if (error == ERESTART) {
 			dmu_tx_wait(tx);
@@ -3306,13 +3377,16 @@ top:
 	 * otherwise, store it just like any other file data.
 	 */
 	if (sizeof (znode_phys_t) + len <= dmu_bonus_max()) {
-		zfs_mknode(dzp, vap, tx, cr, 0, &zp, len, NULL, &fuidp);
+		zfs_mknode(dzp, vap, tx, cr, 0, &zp, len, &acl_ids);
 		if (len != 0)
 			bcopy(link, zp->z_phys + 1, len);
 	} else {
 		dmu_buf_t *dbp;
 
-		zfs_mknode(dzp, vap, tx, cr, 0, &zp, 0, NULL, &fuidp);
+		zfs_mknode(dzp, vap, tx, cr, 0, &zp, 0, &acl_ids);
+
+		if (fuid_dirtied)
+			zfs_fuid_sync(zfsvfs, tx);
 		/*
 		 * Nothing can access the znode yet so no locking needed
 		 * for growing the znode's blocksize.
@@ -3333,15 +3407,14 @@ top:
 	 * Insert the new object into the directory.
 	 */
 	(void) zfs_link_create(dl, zp, tx, ZNEW);
-out:
 	if (error == 0) {
 		uint64_t txtype = TX_SYMLINK;
 		if (flags & FIGNORECASE)
 			txtype |= TX_CI;
 		zfs_log_symlink(zilog, tx, txtype, dzp, zp, name, link);
 	}
-	if (fuidp)
-		zfs_fuid_info_free(fuidp);
+
+	zfs_acl_ids_free(&acl_ids);
 
 	dmu_tx_commit(tx);
 
@@ -3618,6 +3691,12 @@ zfs_putapage(vnode_t *vp, page_t *pp, u_offset_t *offp,
 			pvn_write_done(trunc, flags);
 		len = filesz - off;
 	}
+
+	if (zfs_usergroup_overquota(zfsvfs, B_FALSE, zp->z_phys->zp_uid) ||
+	    zfs_usergroup_overquota(zfsvfs, B_TRUE, zp->z_phys->zp_gid)) {
+		err = EDQUOT;
+		goto out;
+	}
 top:
 	tx = dmu_tx_create(zfsvfs->z_os);
 	dmu_tx_hold_write(tx, zp->z_id, off, len);
@@ -3705,7 +3784,7 @@ zfs_putpage(vnode_t *vp, offset_t off, size_t len, int flags, cred_t *cr,
 	else
 		io_off = 0;
 	if (len > 0 && ISP2(blksz))
-		io_len = P2ROUNDUP_TYPED(len + (io_off - off), blksz, size_t);
+		io_len = P2ROUNDUP_TYPED(len + (off - io_off), blksz, size_t);
 	else
 		io_len = 0;
 
@@ -3869,7 +3948,8 @@ zfs_frlock(vnode_t *vp, int cmd, flock64_t *bfp, int flag, offset_t offset,
  * If we can't find a page in the cache, we will create a new page
  * and fill it with file data.  For efficiency, we may try to fill
  * multiple pages at once (klustering) to fill up the supplied page
- * list.
+ * list.  Note that the pages to be filled are held with an exclusive
+ * lock to prevent access by other threads while they are being filled.
  */
 static int
 zfs_fillpage(vnode_t *vp, u_offset_t off, struct seg *seg,
@@ -3888,7 +3968,8 @@ zfs_fillpage(vnode_t *vp, u_offset_t off, struct seg *seg,
 		 */
 		io_off = off;
 		io_len = PAGESIZE;
-		pp = page_create_va(vp, io_off, io_len, PG_WAIT, seg, addr);
+		pp = page_create_va(vp, io_off, io_len,
+		    PG_EXCL | PG_WAIT, seg, addr);
 	} else {
 		/*
 		 * Try to find enough pages to fill the page list
@@ -3913,7 +3994,8 @@ zfs_fillpage(vnode_t *vp, u_offset_t off, struct seg *seg,
 
 		ASSERT3U(io_off, ==, cur_pp->p_offset);
 		va = zfs_map_page(cur_pp, S_WRITE);
-		err = dmu_read(os, zp->z_id, io_off, PAGESIZE, va);
+		err = dmu_read(os, zp->z_id, io_off, PAGESIZE, va,
+		    DMU_READ_PREFETCH);
 		zfs_unmap_page(cur_pp, va);
 		if (err) {
 			/* On error, toss the entire kluster */
@@ -3991,7 +4073,7 @@ zfs_getpage(vnode_t *vp, offset_t off, size_t len, uint_t *protp,
 		*protp = PROT_ALL;
 
 	/*
-	 * Loop through the requested range [off, off + len] looking
+	 * Loop through the requested range [off, off + len) looking
 	 * for pages.  If we don't find a page, we will need to create
 	 * a new page and fill it with data from the file.
 	 */
@@ -4337,6 +4419,11 @@ zfs_pathconf(vnode_t *vp, int cmd, ulong_t *valp, cred_t *cr,
 		    (vp->v_type == VREG || vp->v_type == VDIR);
 		return (0);
 
+	case _PC_ACCESS_FILTERING:
+		*valp = vfs_has_feature(vp->v_vfsp, VFSFT_ACCESS_FILTER) &&
+		    vp->v_type == VDIR;
+		return (0);
+
 	case _PC_ACL_ENABLED:
 		*valp = _ACL_ACE_ENABLED;
 		return (0);
@@ -4489,6 +4576,22 @@ const fs_operation_def_t zfs_symvnodeops_template[] = {
 };
 
 /*
+ * special share hidden files vnode operations template
+ */
+vnodeops_t *zfs_sharevnodeops;
+const fs_operation_def_t zfs_sharevnodeops_template[] = {
+	VOPNAME_GETATTR,	{ .vop_getattr = zfs_getattr },
+	VOPNAME_ACCESS,		{ .vop_access = zfs_access },
+	VOPNAME_INACTIVE,	{ .vop_inactive = zfs_inactive },
+	VOPNAME_FID,		{ .vop_fid = zfs_fid },
+	VOPNAME_PATHCONF,	{ .vop_pathconf = zfs_pathconf },
+	VOPNAME_GETSECATTR,	{ .vop_getsecattr = zfs_getsecattr },
+	VOPNAME_SETSECATTR,	{ .vop_setsecattr = zfs_setsecattr },
+	VOPNAME_VNEVENT,	{ .vop_vnevent = fs_vnevent_support },
+	NULL,			NULL
+};
+
+/*
  * Extended attribute directory vnode operations template
  *	This template is identical to the directory vnodes
  *	operation template except for restricted operations:
diff --git a/module/zfs/zfs_znode.c b/module/zfs/zfs_znode.c
index 74983cdc5..8ced95174 100644
--- a/module/zfs/zfs_znode.c
+++ b/module/zfs/zfs_znode.c
@@ -87,6 +87,12 @@
  * (such as VFS logic) that will not compile easily in userland.
  */
 #ifdef _KERNEL
+/*
+ * Needed to close a small window in zfs_znode_move() that allows the zfsvfs to
+ * be freed before it can be safely accessed.
+ */
+krwlock_t zfsvfs_lock;
+
 static kmem_cache_t *znode_cache = NULL;
 
 /*ARGSUSED*/
@@ -154,8 +160,9 @@ zfs_znode_cache_destructor(void *buf, void *arg)
 #ifdef	ZNODE_STATS
 static struct {
 	uint64_t zms_zfsvfs_invalid;
+	uint64_t zms_zfsvfs_recheck1;
 	uint64_t zms_zfsvfs_unmounted;
-	uint64_t zms_zfsvfs_recheck_invalid;
+	uint64_t zms_zfsvfs_recheck2;
 	uint64_t zms_obj_held;
 	uint64_t zms_vnode_locked;
 	uint64_t zms_not_only_dnlc;
@@ -206,17 +213,6 @@ zfs_znode_move_impl(znode_t *ozp, znode_t *nzp)
 	POINTER_INVALIDATE(&ozp->z_zfsvfs);
 }
 
-/*
- * Wrapper function for ZFS_ENTER that returns 0 if successful and otherwise
- * returns a non-zero error code.
- */
-static int
-zfs_enter(zfsvfs_t *zfsvfs)
-{
-	ZFS_ENTER(zfsvfs);
-	return (0);
-}
-
 /*ARGSUSED*/
 static kmem_cbrc_t
 zfs_znode_move(void *buf, void *newbuf, size_t size, void *arg)
@@ -240,12 +236,32 @@ zfs_znode_move(void *buf, void *newbuf, size_t size, void *arg)
 	}
 
 	/*
-	 * Ensure that the filesystem is not unmounted during the move.
+	 * Close a small window in which it's possible that the filesystem could
+	 * be unmounted and freed, and zfsvfs, though valid in the previous
+	 * statement, could point to unrelated memory by the time we try to
+	 * prevent the filesystem from being unmounted.
+	 */
+	rw_enter(&zfsvfs_lock, RW_WRITER);
+	if (zfsvfs != ozp->z_zfsvfs) {
+		rw_exit(&zfsvfs_lock);
+		ZNODE_STAT_ADD(znode_move_stats.zms_zfsvfs_recheck1);
+		return (KMEM_CBRC_DONT_KNOW);
+	}
+
+	/*
+	 * If the znode is still valid, then so is the file system. We know that
+	 * no valid file system can be freed while we hold zfsvfs_lock, so we
+	 * can safely ensure that the filesystem is not and will not be
+	 * unmounted. The next statement is equivalent to ZFS_ENTER().
 	 */
-	if (zfs_enter(zfsvfs) != 0) {		/* ZFS_ENTER */
+	rrw_enter(&zfsvfs->z_teardown_lock, RW_READER, FTAG);
+	if (zfsvfs->z_unmounted) {
+		ZFS_EXIT(zfsvfs);
+		rw_exit(&zfsvfs_lock);
 		ZNODE_STAT_ADD(znode_move_stats.zms_zfsvfs_unmounted);
 		return (KMEM_CBRC_DONT_KNOW);
 	}
+	rw_exit(&zfsvfs_lock);
 
 	mutex_enter(&zfsvfs->z_znodes_lock);
 	/*
@@ -255,7 +271,7 @@ zfs_znode_move(void *buf, void *newbuf, size_t size, void *arg)
 	if (zfsvfs != ozp->z_zfsvfs) {
 		mutex_exit(&zfsvfs->z_znodes_lock);
 		ZFS_EXIT(zfsvfs);
-		ZNODE_STAT_ADD(znode_move_stats.zms_zfsvfs_recheck_invalid);
+		ZNODE_STAT_ADD(znode_move_stats.zms_zfsvfs_recheck2);
 		return (KMEM_CBRC_DONT_KNOW);
 	}
 
@@ -311,6 +327,7 @@ zfs_znode_init(void)
 	/*
 	 * Initialize zcache
 	 */
+	rw_init(&zfsvfs_lock, NULL, RW_DEFAULT, NULL);
 	ASSERT(znode_cache == NULL);
 	znode_cache = kmem_cache_create("zfs_znode_cache",
 	    sizeof (znode_t), 0, zfs_znode_cache_constructor,
@@ -332,6 +349,7 @@ zfs_znode_fini(void)
 	if (znode_cache)
 		kmem_cache_destroy(znode_cache);
 	znode_cache = NULL;
+	rw_destroy(&zfsvfs_lock);
 }
 
 struct vnodeops *zfs_dvnodeops;
@@ -339,6 +357,7 @@ struct vnodeops *zfs_fvnodeops;
 struct vnodeops *zfs_symvnodeops;
 struct vnodeops *zfs_xdvnodeops;
 struct vnodeops *zfs_evnodeops;
+struct vnodeops *zfs_sharevnodeops;
 
 void
 zfs_remove_op_tables()
@@ -363,12 +382,15 @@ zfs_remove_op_tables()
 		vn_freevnodeops(zfs_xdvnodeops);
 	if (zfs_evnodeops)
 		vn_freevnodeops(zfs_evnodeops);
+	if (zfs_sharevnodeops)
+		vn_freevnodeops(zfs_sharevnodeops);
 
 	zfs_dvnodeops = NULL;
 	zfs_fvnodeops = NULL;
 	zfs_symvnodeops = NULL;
 	zfs_xdvnodeops = NULL;
 	zfs_evnodeops = NULL;
+	zfs_sharevnodeops = NULL;
 }
 
 extern const fs_operation_def_t zfs_dvnodeops_template[];
@@ -376,6 +398,7 @@ extern const fs_operation_def_t zfs_fvnodeops_template[];
 extern const fs_operation_def_t zfs_xdvnodeops_template[];
 extern const fs_operation_def_t zfs_symvnodeops_template[];
 extern const fs_operation_def_t zfs_evnodeops_template[];
+extern const fs_operation_def_t zfs_sharevnodeops_template[];
 
 int
 zfs_create_op_tables()
@@ -412,103 +435,58 @@ zfs_create_op_tables()
 
 	error = vn_make_ops(MNTTYPE_ZFS, zfs_evnodeops_template,
 	    &zfs_evnodeops);
+	if (error)
+		return (error);
+
+	error = vn_make_ops(MNTTYPE_ZFS, zfs_sharevnodeops_template,
+	    &zfs_sharevnodeops);
 
 	return (error);
 }
 
-/*
- * zfs_init_fs - Initialize the zfsvfs struct and the file system
- *	incore "master" object.  Verify version compatibility.
- */
 int
-zfs_init_fs(zfsvfs_t *zfsvfs, znode_t **zpp)
+zfs_create_share_dir(zfsvfs_t *zfsvfs, dmu_tx_t *tx)
 {
-	extern int zfsfstype;
-
-	objset_t	*os = zfsvfs->z_os;
-	int		i, error;
-	uint64_t fsid_guid;
-	uint64_t zval;
-
-	*zpp = NULL;
-
-	error = zfs_get_zplprop(os, ZFS_PROP_VERSION, &zfsvfs->z_version);
-	if (error) {
-		return (error);
-	} else if (zfsvfs->z_version > ZPL_VERSION) {
-		(void) printf("Mismatched versions:  File system "
-		    "is version %llu on-disk format, which is "
-		    "incompatible with this software version %lld!",
-		    (u_longlong_t)zfsvfs->z_version, ZPL_VERSION);
-		return (ENOTSUP);
-	}
-
-	if ((error = zfs_get_zplprop(os, ZFS_PROP_NORMALIZE, &zval)) != 0)
-		return (error);
-	zfsvfs->z_norm = (int)zval;
-	if ((error = zfs_get_zplprop(os, ZFS_PROP_UTF8ONLY, &zval)) != 0)
-		return (error);
-	zfsvfs->z_utf8 = (zval != 0);
-	if ((error = zfs_get_zplprop(os, ZFS_PROP_CASE, &zval)) != 0)
-		return (error);
-	zfsvfs->z_case = (uint_t)zval;
-	/*
-	 * Fold case on file systems that are always or sometimes case
-	 * insensitive.
-	 */
-	if (zfsvfs->z_case == ZFS_CASE_INSENSITIVE ||
-	    zfsvfs->z_case == ZFS_CASE_MIXED)
-		zfsvfs->z_norm |= U8_TEXTPREP_TOUPPER;
+	zfs_acl_ids_t acl_ids;
+	vattr_t vattr;
+	znode_t *sharezp;
+	vnode_t *vp;
+	znode_t *zp;
+	int error;
 
-	/*
-	 * The fsid is 64 bits, composed of an 8-bit fs type, which
-	 * separates our fsid from any other filesystem types, and a
-	 * 56-bit objset unique ID.  The objset unique ID is unique to
-	 * all objsets open on this system, provided by unique_create().
-	 * The 8-bit fs type must be put in the low bits of fsid[1]
-	 * because that's where other Solaris filesystems put it.
-	 */
-	fsid_guid = dmu_objset_fsid_guid(os);
-	ASSERT((fsid_guid & ~((1ULL<<56)-1)) == 0);
-	zfsvfs->z_vfs->vfs_fsid.val[0] = fsid_guid;
-	zfsvfs->z_vfs->vfs_fsid.val[1] = ((fsid_guid>>32) << 8) |
-	    zfsfstype & 0xFF;
-
-	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_ROOT_OBJ, 8, 1,
-	    &zfsvfs->z_root);
-	if (error)
-		return (error);
-	ASSERT(zfsvfs->z_root != 0);
+	vattr.va_mask = AT_MODE|AT_UID|AT_GID|AT_TYPE;
+	vattr.va_type = VDIR;
+	vattr.va_mode = S_IFDIR|0555;
+	vattr.va_uid = crgetuid(kcred);
+	vattr.va_gid = crgetgid(kcred);
 
-	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_UNLINKED_SET, 8, 1,
-	    &zfsvfs->z_unlinkedobj);
-	if (error)
-		return (error);
+	sharezp = kmem_cache_alloc(znode_cache, KM_SLEEP);
+	sharezp->z_unlinked = 0;
+	sharezp->z_atime_dirty = 0;
+	sharezp->z_zfsvfs = zfsvfs;
 
-	/*
-	 * Initialize zget mutex's
-	 */
-	for (i = 0; i != ZFS_OBJ_MTX_SZ; i++)
-		mutex_init(&zfsvfs->z_hold_mtx[i], NULL, MUTEX_DEFAULT, NULL);
+	vp = ZTOV(sharezp);
+	vn_reinit(vp);
+	vp->v_type = VDIR;
 
-	error = zfs_zget(zfsvfs, zfsvfs->z_root, zpp);
-	if (error) {
-		/*
-		 * On error, we destroy the mutexes here since it's not
-		 * possible for the caller to determine if the mutexes were
-		 * initialized properly.
-		 */
-		for (i = 0; i != ZFS_OBJ_MTX_SZ; i++)
-			mutex_destroy(&zfsvfs->z_hold_mtx[i]);
-		return (error);
-	}
-	ASSERT3U((*zpp)->z_id, ==, zfsvfs->z_root);
-	error = zap_lookup(os, MASTER_NODE_OBJ, ZFS_FUID_TABLES, 8, 1,
-	    &zfsvfs->z_fuid_obj);
-	if (error == ENOENT)
-		error = 0;
+	VERIFY(0 == zfs_acl_ids_create(sharezp, IS_ROOT_NODE, &vattr,
+	    kcred, NULL, &acl_ids));
+	zfs_mknode(sharezp, &vattr, tx, kcred, IS_ROOT_NODE,
+	    &zp, 0, &acl_ids);
+	ASSERT3P(zp, ==, sharezp);
+	ASSERT(!vn_in_dnlc(ZTOV(sharezp))); /* not valid to move */
+	POINTER_INVALIDATE(&sharezp->z_zfsvfs);
+	error = zap_add(zfsvfs->z_os, MASTER_NODE_OBJ,
+	    ZFS_SHARES_DIR, 8, 1, &sharezp->z_id, tx);
+	zfsvfs->z_shares_dir = sharezp->z_id;
+
+	zfs_acl_ids_free(&acl_ids);
+	ZTOV(sharezp)->v_count = 0;
+	dmu_buf_rele(sharezp->z_dbuf, NULL);
+	sharezp->z_dbuf = NULL;
+	kmem_cache_free(znode_cache, sharezp);
 
-	return (0);
+	return (error);
 }
 
 /*
@@ -676,7 +654,10 @@ zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_buf_t *db, int blksz)
 		break;
 	case VREG:
 		vp->v_flag |= VMODSORT;
-		vn_setops(vp, zfs_fvnodeops);
+		if (zp->z_phys->zp_parent == zfsvfs->z_shares_dir)
+			vn_setops(vp, zfs_sharevnodeops);
+		else
+			vn_setops(vp, zfs_fvnodeops);
 		break;
 	case VLNK:
 		vn_setops(vp, zfs_symvnodeops);
@@ -720,8 +701,7 @@ zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_buf_t *db, int blksz)
  */
 void
 zfs_mknode(znode_t *dzp, vattr_t *vap, dmu_tx_t *tx, cred_t *cr,
-    uint_t flag, znode_t **zpp, int bonuslen, zfs_acl_t *setaclp,
-    zfs_fuid_info_t **fuidp)
+    uint_t flag, znode_t **zpp, int bonuslen, zfs_acl_ids_t *acl_ids)
 {
 	dmu_buf_t	*db;
 	znode_phys_t	*pzp;
@@ -846,7 +826,12 @@ zfs_mknode(znode_t *dzp, vattr_t *vap, dmu_tx_t *tx, cred_t *cr,
 		 */
 		*zpp = dzp;
 	}
-	zfs_perm_init(*zpp, dzp, flag, vap, tx, cr, setaclp, fuidp);
+	pzp->zp_uid = acl_ids->z_fuid;
+	pzp->zp_gid = acl_ids->z_fgid;
+	pzp->zp_mode = acl_ids->z_mode;
+	VERIFY(0 == zfs_aclset_common(*zpp, acl_ids->z_aclp, cr, tx));
+	if (vap->va_mask & AT_XVATTR)
+		zfs_xvattr_set(*zpp, (xvattr_t *)vap);
 }
 
 void
@@ -1474,7 +1459,7 @@ void
 zfs_create_fs(objset_t *os, cred_t *cr, nvlist_t *zplprops, dmu_tx_t *tx)
 {
 	zfsvfs_t	zfsvfs;
-	uint64_t	moid, doid, version;
+	uint64_t	moid, obj, version;
 	uint64_t	sense = ZFS_CASE_SENSITIVE;
 	uint64_t	norm = 0;
 	nvpair_t	*elem;
@@ -1483,6 +1468,7 @@ zfs_create_fs(objset_t *os, cred_t *cr, nvlist_t *zplprops, dmu_tx_t *tx)
 	vnode_t		*vp;
 	vattr_t		vattr;
 	znode_t		*zp;
+	zfs_acl_ids_t	acl_ids;
 
 	/*
 	 * First attempt to create master node.
@@ -1499,12 +1485,12 @@ zfs_create_fs(objset_t *os, cred_t *cr, nvlist_t *zplprops, dmu_tx_t *tx)
 	/*
 	 * Set starting attributes.
 	 */
-	if (spa_version(dmu_objset_spa(os)) >= SPA_VERSION_FUID)
+	if (spa_version(dmu_objset_spa(os)) >= SPA_VERSION_USERSPACE)
 		version = ZPL_VERSION;
+	else if (spa_version(dmu_objset_spa(os)) >= SPA_VERSION_FUID)
+		version = ZPL_VERSION_USERSPACE - 1;
 	else
 		version = ZPL_VERSION_FUID - 1;
-	error = zap_update(os, moid, ZPL_VERSION_STR,
-	    8, 1, &version, tx);
 	elem = NULL;
 	while ((elem = nvlist_next_nvpair(zplprops, elem)) != NULL) {
 		/* For the moment we expect all zpl props to be uint64_ts */
@@ -1515,9 +1501,8 @@ zfs_create_fs(objset_t *os, cred_t *cr, nvlist_t *zplprops, dmu_tx_t *tx)
 		VERIFY(nvpair_value_uint64(elem, &val) == 0);
 		name = nvpair_name(elem);
 		if (strcmp(name, zfs_prop_to_name(ZFS_PROP_VERSION)) == 0) {
-			version = val;
-			error = zap_update(os, moid, ZPL_VERSION_STR,
-			    8, 1, &version, tx);
+			if (val < version)
+				version = val;
 		} else {
 			error = zap_update(os, moid, name, 8, 1, &val, tx);
 		}
@@ -1528,13 +1513,14 @@ zfs_create_fs(objset_t *os, cred_t *cr, nvlist_t *zplprops, dmu_tx_t *tx)
 			sense = val;
 	}
 	ASSERT(version != 0);
+	error = zap_update(os, moid, ZPL_VERSION_STR, 8, 1, &version, tx);
 
 	/*
 	 * Create a delete queue.
 	 */
-	doid = zap_create(os, DMU_OT_UNLINKED_SET, DMU_OT_NONE, 0, tx);
+	obj = zap_create(os, DMU_OT_UNLINKED_SET, DMU_OT_NONE, 0, tx);
 
-	error = zap_add(os, moid, ZFS_UNLINKED_SET, 8, 1, &doid, tx);
+	error = zap_add(os, moid, ZFS_UNLINKED_SET, 8, 1, &obj, tx);
 	ASSERT(error == 0);
 
 	/*
@@ -1575,17 +1561,28 @@ zfs_create_fs(objset_t *os, cred_t *cr, nvlist_t *zplprops, dmu_tx_t *tx)
 
 	ASSERT(!POINTER_IS_VALID(rootzp->z_zfsvfs));
 	rootzp->z_zfsvfs = &zfsvfs;
-	zfs_mknode(rootzp, &vattr, tx, cr, IS_ROOT_NODE, &zp, 0, NULL, NULL);
+	VERIFY(0 == zfs_acl_ids_create(rootzp, IS_ROOT_NODE, &vattr,
+	    cr, NULL, &acl_ids));
+	zfs_mknode(rootzp, &vattr, tx, cr, IS_ROOT_NODE, &zp, 0, &acl_ids);
 	ASSERT3P(zp, ==, rootzp);
 	ASSERT(!vn_in_dnlc(ZTOV(rootzp))); /* not valid to move */
 	error = zap_add(os, moid, ZFS_ROOT_OBJ, 8, 1, &rootzp->z_id, tx);
 	ASSERT(error == 0);
+	zfs_acl_ids_free(&acl_ids);
 	POINTER_INVALIDATE(&rootzp->z_zfsvfs);
 
 	ZTOV(rootzp)->v_count = 0;
 	dmu_buf_rele(rootzp->z_dbuf, NULL);
 	rootzp->z_dbuf = NULL;
 	kmem_cache_free(znode_cache, rootzp);
+
+	/*
+	 * Create shares directory
+	 */
+
+	error = zfs_create_share_dir(&zfsvfs, tx);
+
+	ASSERT(error == 0);
 }
 
 #endif /* _KERNEL */
diff --git a/module/zfs/zil.c b/module/zfs/zil.c
index 83fef0d87..53d9d9bf7 100644
--- a/module/zfs/zil.c
+++ b/module/zfs/zil.c
@@ -19,12 +19,13 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
 #include <sys/zfs_context.h>
 #include <sys/spa.h>
+#include <sys/spa_impl.h>
 #include <sys/dmu.h>
 #include <sys/zap.h>
 #include <sys/arc.h>
@@ -471,34 +472,22 @@ zil_destroy(zilog_t *zilog, boolean_t keep_first)
 }
 
 /*
- * zil_rollback_destroy() is only called by the rollback code.
- * We already have a syncing tx. Rollback has exclusive access to the
- * dataset, so we don't have to worry about concurrent zil access.
- * The actual freeing of any log blocks occurs in zil_sync() later in
- * this txg syncing phase.
+ * return true if the initial log block is not valid
  */
-void
-zil_rollback_destroy(zilog_t *zilog, dmu_tx_t *tx)
+static boolean_t
+zil_empty(zilog_t *zilog)
 {
 	const zil_header_t *zh = zilog->zl_header;
-	uint64_t txg;
+	arc_buf_t *abuf = NULL;
 
 	if (BP_IS_HOLE(&zh->zh_log))
-		return;
+		return (B_TRUE);
 
-	txg = dmu_tx_get_txg(tx);
-	ASSERT3U(zilog->zl_destroy_txg, <, txg);
-	zilog->zl_destroy_txg = txg;
-	zilog->zl_keep_first = B_FALSE;
+	if (zil_read_log_block(zilog, &zh->zh_log, &abuf) != 0)
+		return (B_TRUE);
 
-	/*
-	 * Ensure there's no outstanding ZIL IO.  No lwbs or just the
-	 * unused one that allocated in advance is ok.
-	 */
-	ASSERT(zilog->zl_lwb_list.list_head.list_next ==
-	    zilog->zl_lwb_list.list_head.list_prev);
-	(void) zil_parse(zilog, zil_free_log_block, zil_free_log_record,
-	    tx, zh->zh_claim_txg);
+	VERIFY(arc_buf_remove_ref(abuf, &abuf) == 1);
+	return (B_FALSE);
 }
 
 int
@@ -520,6 +509,30 @@ zil_claim(char *osname, void *txarg)
 	zilog = dmu_objset_zil(os);
 	zh = zil_header_in_syncing_context(zilog);
 
+	if (zilog->zl_spa->spa_log_state == SPA_LOG_CLEAR) {
+		if (!BP_IS_HOLE(&zh->zh_log))
+			zio_free_blk(zilog->zl_spa, &zh->zh_log, first_txg);
+		BP_ZERO(&zh->zh_log);
+		dsl_dataset_dirty(dmu_objset_ds(os), tx);
+	}
+
+	/*
+	 * Record here whether the zil has any records to replay.
+	 * If the header block pointer is null or the block points
+	 * to the stubby then we know there are no valid log records.
+	 * We use the header to store this state as the the zilog gets
+	 * freed later in dmu_objset_close().
+	 * The flags (and the rest of the header fields) are cleared in
+	 * zil_sync() as a result of a zil_destroy(), after replaying the log.
+	 *
+	 * Note, the intent log can be empty but still need the
+	 * stubby to be claimed.
+	 */
+	if (!zil_empty(zilog)) {
+		zh->zh_flags |= ZIL_REPLAY_NEEDED;
+		dsl_dataset_dirty(dmu_objset_ds(os), tx);
+	}
+
 	/*
 	 * Claim all log blocks if we haven't already done so, and remember
 	 * the highest claimed sequence number.  This ensures that if we can
@@ -587,36 +600,6 @@ zil_check_log_chain(char *osname, void *txarg)
 	return (error);
 }
 
-/*
- * Clear a log chain
- */
-/* ARGSUSED */
-int
-zil_clear_log_chain(char *osname, void *txarg)
-{
-	zilog_t *zilog;
-	zil_header_t *zh;
-	objset_t *os;
-	dmu_tx_t *tx;
-	int error;
-
-	error = dmu_objset_open(osname, DMU_OST_ANY, DS_MODE_USER, &os);
-	if (error) {
-		cmn_err(CE_WARN, "can't open objset for %s", osname);
-		return (0);
-	}
-
-	zilog = dmu_objset_zil(os);
-	tx = dmu_tx_create(zilog->zl_os);
-	(void) dmu_tx_assign(tx, TXG_WAIT);
-	zh = zil_header_in_syncing_context(zilog);
-	BP_ZERO(&zh->zh_log);
-	dsl_dataset_dirty(dmu_objset_ds(os), tx);
-	dmu_tx_commit(tx);
-	dmu_objset_close(os);
-	return (0);
-}
-
 static int
 zil_vdev_compare(const void *x1, const void *x2)
 {
@@ -719,18 +702,26 @@ zil_lwb_write_done(zio_t *zio)
 	ASSERT(zio->io_bp->blk_fill == 0);
 
 	/*
-	 * Now that we've written this log block, we have a stable pointer
-	 * to the next block in the chain, so it's OK to let the txg in
-	 * which we allocated the next block sync.
+	 * Ensure the lwb buffer pointer is cleared before releasing
+	 * the txg. If we have had an allocation failure and
+	 * the txg is waiting to sync then we want want zil_sync()
+	 * to remove the lwb so that it's not picked up as the next new
+	 * one in zil_commit_writer(). zil_sync() will only remove
+	 * the lwb if lwb_buf is null.
 	 */
-	txg_rele_to_sync(&lwb->lwb_txgh);
-
 	zio_buf_free(lwb->lwb_buf, lwb->lwb_sz);
 	mutex_enter(&zilog->zl_lock);
 	lwb->lwb_buf = NULL;
 	if (zio->io_error)
 		zilog->zl_log_error = B_TRUE;
 	mutex_exit(&zilog->zl_lock);
+
+	/*
+	 * Now that we've written this log block, we have a stable pointer
+	 * to the next block in the chain, so it's OK to let the txg in
+	 * which we allocated the next block sync.
+	 */
+	txg_rele_to_sync(&lwb->lwb_txgh);
 }
 
 /*
@@ -752,9 +743,9 @@ zil_lwb_write_init(zilog_t *zilog, lwb_t *lwb)
 	}
 	if (lwb->lwb_zio == NULL) {
 		lwb->lwb_zio = zio_rewrite(zilog->zl_root_zio, zilog->zl_spa,
-		    0, &lwb->lwb_blk, lwb->lwb_buf,
-		    lwb->lwb_sz, zil_lwb_write_done, lwb,
-		    ZIO_PRIORITY_LOG_WRITE, ZIO_FLAG_CANFAIL, &zb);
+		    0, &lwb->lwb_blk, lwb->lwb_buf, lwb->lwb_sz,
+		    zil_lwb_write_done, lwb, ZIO_PRIORITY_LOG_WRITE,
+		    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, &zb);
 	}
 }
 
@@ -1040,7 +1031,7 @@ zil_clean(zilog_t *zilog)
 	if ((itx != NULL) &&
 	    (itx->itx_lr.lrc_txg <= spa_last_synced_txg(zilog->zl_spa))) {
 		(void) taskq_dispatch(zilog->zl_clean_taskq,
-		    (void (*)(void *))zil_itx_clean, zilog, TQ_NOSLEEP);
+		    (task_func_t *)zil_itx_clean, zilog, TQ_SLEEP);
 	}
 	mutex_exit(&zilog->zl_lock);
 }
@@ -1216,6 +1207,13 @@ zil_sync(zilog_t *zilog, dmu_tx_t *tx)
 	spa_t *spa = zilog->zl_spa;
 	lwb_t *lwb;
 
+	/*
+	 * We don't zero out zl_destroy_txg, so make sure we don't try
+	 * to destroy it twice.
+	 */
+	if (spa_sync_pass(spa) != 1)
+		return;
+
 	mutex_enter(&zilog->zl_lock);
 
 	ASSERT(zilog->zl_stop_sync == 0);
@@ -1226,7 +1224,6 @@ zil_sync(zilog_t *zilog, dmu_tx_t *tx)
 		blkptr_t blk = zh->zh_log;
 
 		ASSERT(list_head(&zilog->zl_lwb_list) == NULL);
-		ASSERT(spa_sync_pass(spa) == 1);
 
 		bzero(zh, sizeof (zil_header_t));
 		bzero(zilog->zl_replayed_seq, sizeof (zilog->zl_replayed_seq));
@@ -1245,12 +1242,7 @@ zil_sync(zilog_t *zilog, dmu_tx_t *tx)
 		}
 	}
 
-	for (;;) {
-		lwb = list_head(&zilog->zl_lwb_list);
-		if (lwb == NULL) {
-			mutex_exit(&zilog->zl_lock);
-			return;
-		}
+	while ((lwb = list_head(&zilog->zl_lwb_list)) != NULL) {
 		zh->zh_log = lwb->lwb_blk;
 		if (lwb->lwb_buf != NULL || lwb->lwb_max_txg > txg)
 			break;
@@ -1344,25 +1336,6 @@ zil_free(zilog_t *zilog)
 }
 
 /*
- * return true if the initial log block is not valid
- */
-static boolean_t
-zil_empty(zilog_t *zilog)
-{
-	const zil_header_t *zh = zilog->zl_header;
-	arc_buf_t *abuf = NULL;
-
-	if (BP_IS_HOLE(&zh->zh_log))
-		return (B_TRUE);
-
-	if (zil_read_log_block(zilog, &zh->zh_log, &abuf) != 0)
-		return (B_TRUE);
-
-	VERIFY(arc_buf_remove_ref(abuf, &abuf) == 1);
-	return (B_FALSE);
-}
-
-/*
  * Open an intent log.
  */
 zilog_t *
@@ -1417,7 +1390,7 @@ zil_suspend(zilog_t *zilog)
 	const zil_header_t *zh = zilog->zl_header;
 
 	mutex_enter(&zilog->zl_lock);
-	if (zh->zh_claim_txg != 0) {		/* unplayed log */
+	if (zh->zh_flags & ZIL_REPLAY_NEEDED) {		/* unplayed log */
 		mutex_exit(&zilog->zl_lock);
 		return (EBUSY);
 	}
@@ -1601,7 +1574,7 @@ zil_replay(objset_t *os, void *arg, zil_replay_func_t *replay_func[TX_MAX_TYPE])
 	const zil_header_t *zh = zilog->zl_header;
 	zil_replay_arg_t zr;
 
-	if (zil_empty(zilog)) {
+	if ((zh->zh_flags & ZIL_REPLAY_NEEDED) == 0) {
 		zil_destroy(zilog, B_TRUE);
 		return;
 	}
@@ -1671,3 +1644,24 @@ out:
 	mutex_exit(&zilog->zl_lock);
 	return (ret);
 }
+
+/* ARGSUSED */
+int
+zil_vdev_offline(char *osname, void *arg)
+{
+	objset_t *os;
+	zilog_t *zilog;
+	int error;
+
+	error = dmu_objset_open(osname, DMU_OST_ANY, DS_MODE_USER, &os);
+	if (error)
+		return (error);
+
+	zilog = dmu_objset_zil(os);
+	if (zil_suspend(zilog) != 0)
+		error = EEXIST;
+	else
+		zil_resume(zilog);
+	dmu_objset_close(os);
+	return (error);
+}
diff --git a/module/zfs/zio.c b/module/zfs/zio.c
index a669ad64a..a2bdab9a7 100644
--- a/module/zfs/zio.c
+++ b/module/zfs/zio.c
@@ -490,11 +490,10 @@ zio_create(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
 		zio->io_bp_orig = *bp;
 		if (type != ZIO_TYPE_WRITE)
 			zio->io_bp = &zio->io_bp_copy;	/* so caller can free */
-		if (zio->io_child_type == ZIO_CHILD_LOGICAL) {
-			if (BP_IS_GANG(bp))
-				pipeline |= ZIO_GANG_STAGES;
+		if (zio->io_child_type == ZIO_CHILD_LOGICAL)
 			zio->io_logical = zio;
-		}
+		if (zio->io_child_type > ZIO_CHILD_GANG && BP_IS_GANG(bp))
+			pipeline |= ZIO_GANG_STAGES;
 	}
 
 	zio->io_spa = spa;
@@ -520,6 +519,8 @@ zio_create(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
 	if (pio != NULL) {
 		if (zio->io_logical == NULL)
 			zio->io_logical = pio->io_logical;
+		if (zio->io_child_type == ZIO_CHILD_GANG)
+			zio->io_gang_leader = pio->io_gang_leader;
 		zio_add_child(pio, zio);
 	}
 
@@ -529,21 +530,11 @@ zio_create(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp,
 static void
 zio_destroy(zio_t *zio)
 {
-	spa_t *spa = zio->io_spa;
-	uint8_t async_root = zio->io_async_root;
-
 	list_destroy(&zio->io_parent_list);
 	list_destroy(&zio->io_child_list);
 	mutex_destroy(&zio->io_lock);
 	cv_destroy(&zio->io_cv);
 	kmem_cache_free(zio_cache, zio);
-
-	if (async_root) {
-		mutex_enter(&spa->spa_async_root_lock);
-		if (--spa->spa_async_root_count == 0)
-			cv_broadcast(&spa->spa_async_root_cv);
-		mutex_exit(&spa->spa_async_root_lock);
-	}
 }
 
 zio_t *
@@ -836,7 +827,8 @@ zio_read_bp_init(zio_t *zio)
 	blkptr_t *bp = zio->io_bp;
 
 	if (BP_GET_COMPRESS(bp) != ZIO_COMPRESS_OFF &&
-	    zio->io_logical == zio && !(zio->io_flags & ZIO_FLAG_RAW)) {
+	    zio->io_child_type == ZIO_CHILD_LOGICAL &&
+	    !(zio->io_flags & ZIO_FLAG_RAW)) {
 		uint64_t csize = BP_GET_PSIZE(bp);
 		void *cbuf = zio_buf_alloc(csize);
 
@@ -885,16 +877,10 @@ zio_write_bp_init(zio_t *zio)
 		 * few passes, stop compressing to ensure convergence.
 		 */
 		pass = spa_sync_pass(zio->io_spa);
-		ASSERT(pass > 1);
 
 		if (pass > SYNC_PASS_DONT_COMPRESS)
 			compress = ZIO_COMPRESS_OFF;
 
-		/*
-		 * Only MOS (objset 0) data should need to be rewritten.
-		 */
-		ASSERT(zio->io_logical->io_bookmark.zb_objset == 0);
-
 		/* Make sure someone doesn't change their mind on overwrites */
 		ASSERT(MIN(zp->zp_ndvas + BP_IS_GANG(bp),
 		    spa_max_replication(zio->io_spa)) == BP_GET_NDVAS(bp));
@@ -956,11 +942,11 @@ zio_taskq_dispatch(zio_t *zio, enum zio_taskq_type q)
 	zio_type_t t = zio->io_type;
 
 	/*
-	 * If we're a config writer, the normal issue and interrupt threads
-	 * may all be blocked waiting for the config lock.  In this case,
-	 * select the otherwise-unused taskq for ZIO_TYPE_NULL.
+	 * If we're a config writer or a probe, the normal issue and
+	 * interrupt threads may all be blocked waiting for the config lock.
+	 * In this case, select the otherwise-unused taskq for ZIO_TYPE_NULL.
 	 */
-	if (zio->io_flags & ZIO_FLAG_CONFIG_WRITER)
+	if (zio->io_flags & (ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_PROBE))
 		t = ZIO_TYPE_NULL;
 
 	/*
@@ -1092,14 +1078,12 @@ zio_nowait(zio_t *zio)
 	    zio_unique_parent(zio) == NULL) {
 		/*
 		 * This is a logical async I/O with no parent to wait for it.
-		 * Track how many outstanding I/Os of this type exist so
-		 * that spa_unload() knows when they are all done.
+		 * We add it to the spa_async_root_zio "Godfather" I/O which
+		 * will ensure they complete prior to unloading the pool.
 		 */
 		spa_t *spa = zio->io_spa;
-		zio->io_async_root = B_TRUE;
-		mutex_enter(&spa->spa_async_root_lock);
-		spa->spa_async_root_count++;
-		mutex_exit(&spa->spa_async_root_lock);
+
+		zio_add_child(spa->spa_async_zio_root, zio);
 	}
 
 	zio_execute(zio);
@@ -1118,6 +1102,8 @@ zio_reexecute(zio_t *pio)
 
 	ASSERT(pio->io_child_type == ZIO_CHILD_LOGICAL);
 	ASSERT(pio->io_orig_stage == ZIO_STAGE_OPEN);
+	ASSERT(pio->io_gang_leader == NULL);
+	ASSERT(pio->io_gang_tree == NULL);
 
 	pio->io_flags = pio->io_orig_flags;
 	pio->io_stage = pio->io_orig_stage;
@@ -1161,8 +1147,11 @@ zio_reexecute(zio_t *pio)
 
 	/*
 	 * Now that all children have been reexecuted, execute the parent.
+	 * We don't reexecute "The Godfather" I/O here as it's the
+	 * responsibility of the caller to wait on him.
 	 */
-	zio_execute(pio);
+	if (!(pio->io_flags & ZIO_FLAG_GODFATHER))
+		zio_execute(pio);
 }
 
 void
@@ -1178,11 +1167,14 @@ zio_suspend(spa_t *spa, zio_t *zio)
 	mutex_enter(&spa->spa_suspend_lock);
 
 	if (spa->spa_suspend_zio_root == NULL)
-		spa->spa_suspend_zio_root = zio_root(spa, NULL, NULL, 0);
+		spa->spa_suspend_zio_root = zio_root(spa, NULL, NULL,
+		    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE |
+		    ZIO_FLAG_GODFATHER);
 
 	spa->spa_suspended = B_TRUE;
 
 	if (zio != NULL) {
+		ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER));
 		ASSERT(zio != spa->spa_suspend_zio_root);
 		ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
 		ASSERT(zio_unique_parent(zio) == NULL);
@@ -1193,10 +1185,10 @@ zio_suspend(spa_t *spa, zio_t *zio)
 	mutex_exit(&spa->spa_suspend_lock);
 }
 
-void
+int
 zio_resume(spa_t *spa)
 {
-	zio_t *pio, *cio, *cio_next;
+	zio_t *pio;
 
 	/*
 	 * Reexecute all previously suspended i/o.
@@ -1209,18 +1201,10 @@ zio_resume(spa_t *spa)
 	mutex_exit(&spa->spa_suspend_lock);
 
 	if (pio == NULL)
-		return;
-
-	for (cio = zio_walk_children(pio); cio != NULL; cio = cio_next) {
-		zio_link_t *zl = pio->io_walk_link;
-		cio_next = zio_walk_children(pio);
-		zio_remove_child(pio, cio, zl);
-		zio_reexecute(cio);
-	}
+		return (0);
 
-	ASSERT(pio->io_children[ZIO_CHILD_LOGICAL][ZIO_WAIT_DONE] == 0);
-
-	(void) zio_wait(pio);
+	zio_reexecute(pio);
+	return (zio_wait(pio));
 }
 
 void
@@ -1327,7 +1311,7 @@ zio_rewrite_gang(zio_t *pio, blkptr_t *bp, zio_gang_node_t *gn, void *data)
 		 * (Presently, nothing actually uses interior data checksums;
 		 * this is just good hygiene.)
 		 */
-		if (gn != pio->io_logical->io_gang_tree) {
+		if (gn != pio->io_gang_leader->io_gang_tree) {
 			zio_checksum_compute(zio, BP_GET_CHECKSUM(bp),
 			    data, BP_GET_PSIZE(bp));
 		}
@@ -1409,27 +1393,26 @@ zio_gang_tree_free(zio_gang_node_t **gnpp)
 }
 
 static void
-zio_gang_tree_assemble(zio_t *lio, blkptr_t *bp, zio_gang_node_t **gnpp)
+zio_gang_tree_assemble(zio_t *gio, blkptr_t *bp, zio_gang_node_t **gnpp)
 {
 	zio_gang_node_t *gn = zio_gang_node_alloc(gnpp);
 
-	ASSERT(lio->io_logical == lio);
+	ASSERT(gio->io_gang_leader == gio);
 	ASSERT(BP_IS_GANG(bp));
 
-	zio_nowait(zio_read(lio, lio->io_spa, bp, gn->gn_gbh,
+	zio_nowait(zio_read(gio, gio->io_spa, bp, gn->gn_gbh,
 	    SPA_GANGBLOCKSIZE, zio_gang_tree_assemble_done, gn,
-	    lio->io_priority, ZIO_GANG_CHILD_FLAGS(lio), &lio->io_bookmark));
+	    gio->io_priority, ZIO_GANG_CHILD_FLAGS(gio), &gio->io_bookmark));
 }
 
 static void
 zio_gang_tree_assemble_done(zio_t *zio)
 {
-	zio_t *lio = zio->io_logical;
+	zio_t *gio = zio->io_gang_leader;
 	zio_gang_node_t *gn = zio->io_private;
 	blkptr_t *bp = zio->io_bp;
-	zio_t *pio = zio_unique_parent(zio);
 
-	ASSERT(pio == lio);
+	ASSERT(gio == zio_unique_parent(zio));
 	ASSERT(zio_walk_children(zio) == NULL);
 
 	if (zio->io_error)
@@ -1446,25 +1429,25 @@ zio_gang_tree_assemble_done(zio_t *zio)
 		blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g];
 		if (!BP_IS_GANG(gbp))
 			continue;
-		zio_gang_tree_assemble(lio, gbp, &gn->gn_child[g]);
+		zio_gang_tree_assemble(gio, gbp, &gn->gn_child[g]);
 	}
 }
 
 static void
 zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data)
 {
-	zio_t *lio = pio->io_logical;
+	zio_t *gio = pio->io_gang_leader;
 	zio_t *zio;
 
 	ASSERT(BP_IS_GANG(bp) == !!gn);
-	ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(lio->io_bp));
-	ASSERT(BP_GET_LSIZE(bp) == BP_GET_PSIZE(bp) || gn == lio->io_gang_tree);
+	ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(gio->io_bp));
+	ASSERT(BP_GET_LSIZE(bp) == BP_GET_PSIZE(bp) || gn == gio->io_gang_tree);
 
 	/*
 	 * If you're a gang header, your data is in gn->gn_gbh.
 	 * If you're a gang member, your data is in 'data' and gn == NULL.
 	 */
-	zio = zio_gang_issue_func[lio->io_type](pio, bp, gn, data);
+	zio = zio_gang_issue_func[gio->io_type](pio, bp, gn, data);
 
 	if (gn != NULL) {
 		ASSERT(gn->gn_gbh->zg_tail.zbt_magic == ZBT_MAGIC);
@@ -1478,8 +1461,8 @@ zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data)
 		}
 	}
 
-	if (gn == lio->io_gang_tree)
-		ASSERT3P((char *)lio->io_data + lio->io_size, ==, data);
+	if (gn == gio->io_gang_tree)
+		ASSERT3P((char *)gio->io_data + gio->io_size, ==, data);
 
 	if (zio != pio)
 		zio_nowait(zio);
@@ -1490,7 +1473,10 @@ zio_gang_assemble(zio_t *zio)
 {
 	blkptr_t *bp = zio->io_bp;
 
-	ASSERT(BP_IS_GANG(bp) && zio == zio->io_logical);
+	ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == NULL);
+	ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
+
+	zio->io_gang_leader = zio;
 
 	zio_gang_tree_assemble(zio, bp, &zio->io_gang_tree);
 
@@ -1500,18 +1486,18 @@ zio_gang_assemble(zio_t *zio)
 static int
 zio_gang_issue(zio_t *zio)
 {
-	zio_t *lio = zio->io_logical;
 	blkptr_t *bp = zio->io_bp;
 
 	if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_DONE))
 		return (ZIO_PIPELINE_STOP);
 
-	ASSERT(BP_IS_GANG(bp) && zio == lio);
+	ASSERT(BP_IS_GANG(bp) && zio->io_gang_leader == zio);
+	ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
 
 	if (zio->io_child_error[ZIO_CHILD_GANG] == 0)
-		zio_gang_tree_issue(lio, lio->io_gang_tree, bp, lio->io_data);
+		zio_gang_tree_issue(zio, zio->io_gang_tree, bp, zio->io_data);
 	else
-		zio_gang_tree_free(&lio->io_gang_tree);
+		zio_gang_tree_free(&zio->io_gang_tree);
 
 	zio->io_pipeline = ZIO_INTERLOCK_PIPELINE;
 
@@ -1522,7 +1508,7 @@ static void
 zio_write_gang_member_ready(zio_t *zio)
 {
 	zio_t *pio = zio_unique_parent(zio);
-	zio_t *lio = zio->io_logical;
+	zio_t *gio = zio->io_gang_leader;
 	dva_t *cdva = zio->io_bp->blk_dva;
 	dva_t *pdva = pio->io_bp->blk_dva;
 	uint64_t asize;
@@ -1533,7 +1519,7 @@ zio_write_gang_member_ready(zio_t *zio)
 	ASSERT(BP_IS_HOLE(&zio->io_bp_orig));
 
 	ASSERT(zio->io_child_type == ZIO_CHILD_GANG);
-	ASSERT3U(zio->io_prop.zp_ndvas, ==, lio->io_prop.zp_ndvas);
+	ASSERT3U(zio->io_prop.zp_ndvas, ==, gio->io_prop.zp_ndvas);
 	ASSERT3U(zio->io_prop.zp_ndvas, <=, BP_GET_NDVAS(zio->io_bp));
 	ASSERT3U(pio->io_prop.zp_ndvas, <=, BP_GET_NDVAS(pio->io_bp));
 	ASSERT3U(BP_GET_NDVAS(zio->io_bp), <=, BP_GET_NDVAS(pio->io_bp));
@@ -1553,28 +1539,28 @@ zio_write_gang_block(zio_t *pio)
 {
 	spa_t *spa = pio->io_spa;
 	blkptr_t *bp = pio->io_bp;
-	zio_t *lio = pio->io_logical;
+	zio_t *gio = pio->io_gang_leader;
 	zio_t *zio;
 	zio_gang_node_t *gn, **gnpp;
 	zio_gbh_phys_t *gbh;
 	uint64_t txg = pio->io_txg;
 	uint64_t resid = pio->io_size;
 	uint64_t lsize;
-	int ndvas = lio->io_prop.zp_ndvas;
+	int ndvas = gio->io_prop.zp_ndvas;
 	int gbh_ndvas = MIN(ndvas + 1, spa_max_replication(spa));
 	zio_prop_t zp;
 	int error;
 
 	error = metaslab_alloc(spa, spa->spa_normal_class, SPA_GANGBLOCKSIZE,
-	    bp, gbh_ndvas, txg, pio == lio ? NULL : lio->io_bp,
+	    bp, gbh_ndvas, txg, pio == gio ? NULL : gio->io_bp,
 	    METASLAB_HINTBP_FAVOR | METASLAB_GANG_HEADER);
 	if (error) {
 		pio->io_error = error;
 		return (ZIO_PIPELINE_CONTINUE);
 	}
 
-	if (pio == lio) {
-		gnpp = &lio->io_gang_tree;
+	if (pio == gio) {
+		gnpp = &gio->io_gang_tree;
 	} else {
 		gnpp = pio->io_private;
 		ASSERT(pio->io_ready == zio_write_gang_member_ready);
@@ -1598,11 +1584,11 @@ zio_write_gang_block(zio_t *pio)
 		    SPA_MINBLOCKSIZE);
 		ASSERT(lsize >= SPA_MINBLOCKSIZE && lsize <= resid);
 
-		zp.zp_checksum = lio->io_prop.zp_checksum;
+		zp.zp_checksum = gio->io_prop.zp_checksum;
 		zp.zp_compress = ZIO_COMPRESS_OFF;
 		zp.zp_type = DMU_OT_NONE;
 		zp.zp_level = 0;
-		zp.zp_ndvas = lio->io_prop.zp_ndvas;
+		zp.zp_ndvas = gio->io_prop.zp_ndvas;
 
 		zio_nowait(zio_write(zio, spa, txg, &gbh->zg_blkptr[g],
 		    (char *)pio->io_data + (pio->io_size - resid), lsize, &zp,
@@ -1635,6 +1621,11 @@ zio_dva_allocate(zio_t *zio)
 	blkptr_t *bp = zio->io_bp;
 	int error;
 
+	if (zio->io_gang_leader == NULL) {
+		ASSERT(zio->io_child_type > ZIO_CHILD_GANG);
+		zio->io_gang_leader = zio;
+	}
+
 	ASSERT(BP_IS_HOLE(bp));
 	ASSERT3U(BP_GET_NDVAS(bp), ==, 0);
 	ASSERT3U(zio->io_prop.zp_ndvas, >, 0);
@@ -1864,7 +1855,8 @@ zio_vdev_io_done(zio_t *zio)
 			vdev_cache_write(zio);
 
 		if (zio_injection_enabled && zio->io_error == 0)
-			zio->io_error = zio_handle_device_injection(vd, EIO);
+			zio->io_error = zio_handle_device_injection(vd,
+			    zio, EIO);
 
 		if (zio_injection_enabled && zio->io_error == 0)
 			zio->io_error = zio_handle_label_injection(zio, EIO);
@@ -2079,11 +2071,10 @@ zio_ready(zio_t *zio)
 	blkptr_t *bp = zio->io_bp;
 	zio_t *pio, *pio_next;
 
-	if (zio->io_ready) {
-		if (BP_IS_GANG(bp) &&
-		    zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY))
-			return (ZIO_PIPELINE_STOP);
+	if (zio_wait_for_children(zio, ZIO_CHILD_GANG, ZIO_WAIT_READY))
+		return (ZIO_PIPELINE_STOP);
 
+	if (zio->io_ready) {
 		ASSERT(IO_IS_ALLOCATING(zio));
 		ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp));
 		ASSERT(zio->io_children[ZIO_CHILD_GANG][ZIO_WAIT_READY] == 0);
@@ -2128,7 +2119,7 @@ zio_done(zio_t *zio)
 	zio_t *pio, *pio_next;
 
 	/*
-	 * If our of children haven't all completed,
+	 * If our children haven't all completed,
 	 * wait for them and then repeat this pipeline stage.
 	 */
 	if (zio_wait_for_children(zio, ZIO_CHILD_VDEV, ZIO_WAIT_DONE) ||
@@ -2219,6 +2210,21 @@ zio_done(zio_t *zio)
 	 */
 	zio_inherit_child_errors(zio, ZIO_CHILD_LOGICAL);
 
+	if ((zio->io_error || zio->io_reexecute) && IO_IS_ALLOCATING(zio) &&
+	    zio->io_child_type == ZIO_CHILD_LOGICAL) {
+		ASSERT(zio->io_child_type != ZIO_CHILD_GANG);
+		zio_dva_unallocate(zio, zio->io_gang_tree, bp);
+	}
+
+	zio_gang_tree_free(&zio->io_gang_tree);
+
+	/*
+	 * Godfather I/Os should never suspend.
+	 */
+	if ((zio->io_flags & ZIO_FLAG_GODFATHER) &&
+	    (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND))
+		zio->io_reexecute = 0;
+
 	if (zio->io_reexecute) {
 		/*
 		 * This is a logical I/O that wants to reexecute.
@@ -2235,21 +2241,37 @@ zio_done(zio_t *zio)
 		 */
 		ASSERT(zio->io_child_type == ZIO_CHILD_LOGICAL);
 
-		if (IO_IS_ALLOCATING(zio))
-			zio_dva_unallocate(zio, zio->io_gang_tree, bp);
-
-		zio_gang_tree_free(&zio->io_gang_tree);
+		zio->io_gang_leader = NULL;
 
 		mutex_enter(&zio->io_lock);
 		zio->io_state[ZIO_WAIT_DONE] = 1;
 		mutex_exit(&zio->io_lock);
 
+		/*
+		 * "The Godfather" I/O monitors its children but is
+		 * not a true parent to them. It will track them through
+		 * the pipeline but severs its ties whenever they get into
+		 * trouble (e.g. suspended). This allows "The Godfather"
+		 * I/O to return status without blocking.
+		 */
+		for (pio = zio_walk_parents(zio); pio != NULL; pio = pio_next) {
+			zio_link_t *zl = zio->io_walk_link;
+			pio_next = zio_walk_parents(zio);
+
+			if ((pio->io_flags & ZIO_FLAG_GODFATHER) &&
+			    (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND)) {
+				zio_remove_child(pio, zio, zl);
+				zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
+			}
+		}
+
 		if ((pio = zio_unique_parent(zio)) != NULL) {
 			/*
 			 * We're not a root i/o, so there's nothing to do
 			 * but notify our parent.  Don't propagate errors
 			 * upward since we haven't permanently failed yet.
 			 */
+			ASSERT(!(zio->io_flags & ZIO_FLAG_GODFATHER));
 			zio->io_flags |= ZIO_FLAG_DONT_PROPAGATE;
 			zio_notify_parent(pio, zio, ZIO_WAIT_DONE);
 		} else if (zio->io_reexecute & ZIO_REEXECUTE_SUSPEND) {
@@ -2282,8 +2304,6 @@ zio_done(zio_t *zio)
 	if (zio->io_done)
 		zio->io_done(zio);
 
-	zio_gang_tree_free(&zio->io_gang_tree);
-
 	mutex_enter(&zio->io_lock);
 	zio->io_state[ZIO_WAIT_DONE] = 1;
 	mutex_exit(&zio->io_lock);
diff --git a/module/zfs/zio_inject.c b/module/zfs/zio_inject.c
index b3469fdd5..f8e6880c9 100644
--- a/module/zfs/zio_inject.c
+++ b/module/zfs/zio_inject.c
@@ -19,7 +19,7 @@
  * CDDL HEADER END
  */
 /*
- * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -195,7 +195,7 @@ zio_handle_label_injection(zio_t *zio, int error)
 
 
 int
-zio_handle_device_injection(vdev_t *vd, int error)
+zio_handle_device_injection(vdev_t *vd, zio_t *zio, int error)
 {
 	inject_handler_t *handler;
 	int ret = 0;
@@ -210,6 +210,12 @@ zio_handle_device_injection(vdev_t *vd, int error)
 			continue;
 
 		if (vd->vdev_guid == handler->zi_record.zi_guid) {
+			if (handler->zi_record.zi_failfast &&
+			    (zio == NULL || (zio->io_flags &
+			    (ZIO_FLAG_IO_RETRY | ZIO_FLAG_TRYHARD)))) {
+				continue;
+			}
+
 			if (handler->zi_record.zi_error == error) {
 				/*
 				 * For a failed open, pretend like the device
diff --git a/module/zfs/zvol.c b/module/zfs/zvol.c
index d3be8fb50..cfd3b3dbd 100644
--- a/module/zfs/zvol.c
+++ b/module/zfs/zvol.c
@@ -107,7 +107,7 @@ typedef struct zvol_state {
 	uint64_t	zv_volblocksize; /* volume block size */
 	minor_t		zv_minor;	/* minor number */
 	uint8_t		zv_min_bs;	/* minimum addressable block shift */
-	uint8_t		zv_flags;	/* readonly; dumpified */
+	uint8_t		zv_flags;	/* readonly, dumpified, etc. */
 	objset_t	*zv_objset;	/* objset handle */
 	uint32_t	zv_mode;	/* DS_MODE_* flags at open time */
 	uint32_t	zv_open_count[OTYPCNT];	/* open counts */
@@ -123,6 +123,7 @@ typedef struct zvol_state {
 #define	ZVOL_RDONLY	0x1
 #define	ZVOL_DUMPIFIED	0x2
 #define	ZVOL_EXCL	0x4
+#define	ZVOL_WCE	0x8
 
 /*
  * zvol maximum transfer in one DMU tx.
@@ -741,6 +742,27 @@ zvol_set_volsize(const char *name, major_t maj, uint64_t volsize)
 		}
 	}
 
+	/*
+	 * Generate a LUN expansion event.
+	 */
+	if (error == 0) {
+		sysevent_id_t eid;
+		nvlist_t *attr;
+		char *physpath = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
+
+		(void) snprintf(physpath, MAXPATHLEN, "%s%uc", ZVOL_PSEUDO_DEV,
+		    zv->zv_minor);
+
+		VERIFY(nvlist_alloc(&attr, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+		VERIFY(nvlist_add_string(attr, DEV_PHYS_PATH, physpath) == 0);
+
+		(void) ddi_log_sysevent(zfs_dip, SUNW_VENDOR, EC_DEV_STATUS,
+		    ESC_DEV_DLE, attr, &eid, DDI_SLEEP);
+
+		nvlist_free(attr);
+		kmem_free(physpath, MAXPATHLEN);
+	}
+
 out:
 	if (state.zv_objset)
 		dmu_objset_close(state.zv_objset);
@@ -924,7 +946,8 @@ zvol_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio)
 	 * we don't have to write the data twice.
 	 */
 	if (buf != NULL) /* immediate write */
-		return (dmu_read(os, ZVOL_OBJ, lr->lr_offset, dlen, buf));
+		return (dmu_read(os, ZVOL_OBJ, lr->lr_offset, dlen, buf,
+		    DMU_READ_NO_PREFETCH));
 
 	zgd = (zgd_t *)kmem_alloc(sizeof (zgd_t), KM_SLEEP);
 	zgd->zgd_zilog = zv->zv_zilog;
@@ -968,11 +991,15 @@ zvol_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio)
 ssize_t zvol_immediate_write_sz = 32768;
 
 static void
-zvol_log_write(zvol_state_t *zv, dmu_tx_t *tx, offset_t off, ssize_t len)
+zvol_log_write(zvol_state_t *zv, dmu_tx_t *tx, offset_t off, ssize_t resid,
+    boolean_t sync)
 {
 	uint32_t blocksize = zv->zv_volblocksize;
 	zilog_t *zilog = zv->zv_zilog;
-	lr_write_t *lr;
+	boolean_t slogging;
+
+	if (zil_disable)
+		return;
 
 	if (zilog->zl_replay) {
 		dsl_dataset_dirty(dmu_objset_ds(zilog->zl_os), tx);
@@ -981,23 +1008,58 @@ zvol_log_write(zvol_state_t *zv, dmu_tx_t *tx, offset_t off, ssize_t len)
 		return;
 	}
 
-	while (len) {
-		ssize_t nbytes = MIN(len, blocksize - P2PHASE(off, blocksize));
-		itx_t *itx = zil_itx_create(TX_WRITE, sizeof (*lr));
+	slogging = spa_has_slogs(zilog->zl_spa);
 
-		itx->itx_wr_state =
-		    len > zvol_immediate_write_sz ?  WR_INDIRECT : WR_NEED_COPY;
-		itx->itx_private = zv;
+	while (resid) {
+		itx_t *itx;
+		lr_write_t *lr;
+		ssize_t len;
+		itx_wr_state_t write_state;
+
+		/*
+		 * Unlike zfs_log_write() we can be called with
+		 * upto DMU_MAX_ACCESS/2 (5MB) writes.
+		 */
+		if (blocksize > zvol_immediate_write_sz && !slogging &&
+		    resid >= blocksize && off % blocksize == 0) {
+			write_state = WR_INDIRECT; /* uses dmu_sync */
+			len = blocksize;
+		} else if (sync) {
+			write_state = WR_COPIED;
+			len = MIN(ZIL_MAX_LOG_DATA, resid);
+		} else {
+			write_state = WR_NEED_COPY;
+			len = MIN(ZIL_MAX_LOG_DATA, resid);
+		}
+
+		itx = zil_itx_create(TX_WRITE, sizeof (*lr) +
+		    (write_state == WR_COPIED ? len : 0));
 		lr = (lr_write_t *)&itx->itx_lr;
+		if (write_state == WR_COPIED && dmu_read(zv->zv_objset,
+		    ZVOL_OBJ, off, len, lr + 1, DMU_READ_NO_PREFETCH) != 0) {
+			kmem_free(itx, offsetof(itx_t, itx_lr) +
+			    itx->itx_lr.lrc_reclen);
+			itx = zil_itx_create(TX_WRITE, sizeof (*lr));
+			lr = (lr_write_t *)&itx->itx_lr;
+			write_state = WR_NEED_COPY;
+		}
+
+		itx->itx_wr_state = write_state;
+		if (write_state == WR_NEED_COPY)
+			itx->itx_sod += len;
 		lr->lr_foid = ZVOL_OBJ;
 		lr->lr_offset = off;
-		lr->lr_length = nbytes;
+		lr->lr_length = len;
 		lr->lr_blkoff = off - P2ALIGN_TYPED(off, blocksize, uint64_t);
 		BP_ZERO(&lr->lr_blkptr);
 
+		itx->itx_private = zv;
+		itx->itx_sync = sync;
+
 		(void) zil_itx_assign(zilog, itx, tx);
-		len -= nbytes;
-		off += nbytes;
+
+		off += len;
+		resid -= len;
 	}
 }
 
@@ -1010,7 +1072,9 @@ zvol_dumpio_vdev(vdev_t *vd, void *addr, uint64_t offset, uint64_t size,
 	int numerrors = 0;
 
 	for (c = 0; c < vd->vdev_children; c++) {
-		ASSERT(vd->vdev_ops == &vdev_mirror_ops);
+		ASSERT(vd->vdev_ops == &vdev_mirror_ops ||
+		    vd->vdev_ops == &vdev_replacing_ops ||
+		    vd->vdev_ops == &vdev_spare_ops);
 		int err = zvol_dumpio_vdev(vd->vdev_child[c],
 		    addr, offset, size, doread, isdump);
 		if (err != 0) {
@@ -1086,6 +1150,7 @@ zvol_strategy(buf_t *bp)
 	int error = 0;
 	boolean_t doread = bp->b_flags & B_READ;
 	boolean_t is_dump = zv->zv_flags & ZVOL_DUMPIFIED;
+	boolean_t sync;
 
 	if (zv == NULL) {
 		bioerror(bp, ENXIO);
@@ -1123,6 +1188,9 @@ zvol_strategy(buf_t *bp)
 		return (0);
 	}
 
+	sync = !(bp->b_flags & B_ASYNC) && !doread && !is_dump &&
+	    !(zv->zv_flags & ZVOL_WCE) && !zil_disable;
+
 	/*
 	 * There must be no buffer changes when doing a dmu_sync() because
 	 * we can't change the data whilst calculating the checksum.
@@ -1137,7 +1205,8 @@ zvol_strategy(buf_t *bp)
 			error = zvol_dumpio(zv, addr, off, size,
 			    doread, B_FALSE);
 		} else if (doread) {
-			error = dmu_read(os, ZVOL_OBJ, off, size, addr);
+			error = dmu_read(os, ZVOL_OBJ, off, size, addr,
+			    DMU_READ_PREFETCH);
 		} else {
 			dmu_tx_t *tx = dmu_tx_create(os);
 			dmu_tx_hold_write(tx, ZVOL_OBJ, off, size);
@@ -1146,7 +1215,7 @@ zvol_strategy(buf_t *bp)
 				dmu_tx_abort(tx);
 			} else {
 				dmu_write(os, ZVOL_OBJ, off, size, addr, tx);
-				zvol_log_write(zv, tx, off, size);
+				zvol_log_write(zv, tx, off, size, sync);
 				dmu_tx_commit(tx);
 			}
 		}
@@ -1165,7 +1234,7 @@ zvol_strategy(buf_t *bp)
 	if ((bp->b_resid = resid) == bp->b_bcount)
 		bioerror(bp, off > volsize ? EINVAL : error);
 
-	if (!(bp->b_flags & B_ASYNC) && !doread && !zil_disable && !is_dump)
+	if (sync)
 		zil_commit(zv->zv_zilog, UINT64_MAX, ZVOL_OBJ);
 	biodone(bp);
 
@@ -1280,6 +1349,7 @@ zvol_write(dev_t dev, uio_t *uio, cred_t *cr)
 	uint64_t volsize;
 	rl_t *rl;
 	int error = 0;
+	boolean_t sync;
 
 	if (minor == 0)			/* This is the control device */
 		return (ENXIO);
@@ -1299,6 +1369,8 @@ zvol_write(dev_t dev, uio_t *uio, cred_t *cr)
 		return (error);
 	}
 
+	sync = !(zv->zv_flags & ZVOL_WCE) && !zil_disable;
+
 	rl = zfs_range_lock(&zv->zv_znode, uio->uio_loffset, uio->uio_resid,
 	    RL_WRITER);
 	while (uio->uio_resid > 0 && uio->uio_loffset < volsize) {
@@ -1317,14 +1389,14 @@ zvol_write(dev_t dev, uio_t *uio, cred_t *cr)
 		}
 		error = dmu_write_uio(zv->zv_objset, ZVOL_OBJ, uio, bytes, tx);
 		if (error == 0)
-			zvol_log_write(zv, tx, off, bytes);
+			zvol_log_write(zv, tx, off, bytes, sync);
 		dmu_tx_commit(tx);
 
 		if (error)
 			break;
 	}
 	zfs_range_unlock(rl);
-	if (!zil_disable)
+	if (sync)
 		zil_commit(zv->zv_zilog, UINT64_MAX, ZVOL_OBJ);
 	return (error);
 }
@@ -1408,6 +1480,7 @@ zvol_ioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *cr, int *rvalp)
 		mutex_exit(&zvol_state_lock);
 		return (ENXIO);
 	}
+	ASSERT(zv->zv_total_opens > 0);
 
 	switch (cmd) {
 
@@ -1444,12 +1517,40 @@ zvol_ioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *cr, int *rvalp)
 
 	case DKIOCFLUSHWRITECACHE:
 		dkc = (struct dk_callback *)arg;
+		mutex_exit(&zvol_state_lock);
 		zil_commit(zv->zv_zilog, UINT64_MAX, ZVOL_OBJ);
 		if ((flag & FKIOCTL) && dkc != NULL && dkc->dkc_callback) {
 			(*dkc->dkc_callback)(dkc->dkc_cookie, error);
 			error = 0;
 		}
-		break;
+		return (error);
+
+	case DKIOCGETWCE:
+		{
+			int wce = (zv->zv_flags & ZVOL_WCE) ? 1 : 0;
+			if (ddi_copyout(&wce, (void *)arg, sizeof (int),
+			    flag))
+				error = EFAULT;
+			break;
+		}
+	case DKIOCSETWCE:
+		{
+			int wce;
+			if (ddi_copyin((void *)arg, &wce, sizeof (int),
+			    flag)) {
+				error = EFAULT;
+				break;
+			}
+			if (wce) {
+				zv->zv_flags |= ZVOL_WCE;
+				mutex_exit(&zvol_state_lock);
+			} else {
+				zv->zv_flags &= ~ZVOL_WCE;
+				mutex_exit(&zvol_state_lock);
+				zil_commit(zv->zv_zilog, UINT64_MAX, ZVOL_OBJ);
+			}
+			return (0);
+		}
 
 	case DKIOCGGEOM:
 	case DKIOCGVTOC:
@@ -1468,6 +1569,8 @@ zvol_ioctl(dev_t dev, int cmd, intptr_t arg, int flag, cred_t *cr, int *rvalp)
 		break;
 
 	case DKIOCDUMPFINI:
+		if (!(zv->zv_flags & ZVOL_DUMPIFIED))
+			break;
 		rl = zfs_range_lock(&zv->zv_znode, 0, zv->zv_volsize,
 		    RL_WRITER);
 		error = zvol_dump_fini(zv);