Move the world out of /zfs/ and seperate out module build tree

1 files changed, 1136 insertions, 0 deletions

diff --git a/module/zfs/zap.c b/module/zfs/zap.c
new file mode 100644
index 000000000..ca859ec35
--- /dev/null
+++ b/module/zfs/zap.c
@@ -0,0 +1,1136 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2008 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.
+ *
+ * The zdir is an extendable hash data structure. There is a table of
+ * pointers to buckets (zap_t->zd_data->zd_leafs). The buckets are
+ * each a constant size and hold a variable number of directory entries.
+ * The buckets (aka "leaf nodes") are implemented in zap_leaf.c.
+ *
+ * The pointer table holds a power of 2 number of pointers.
+ * (1<<zap_t->zd_data->zd_phys->zd_prefix_len).  The bucket pointed to
+ * by the pointer at index i in the table holds entries whose hash value
+ * has a zd_prefix_len - bit prefix
+ */
+
+#include <sys/spa.h>
+#include <sys/dmu.h>
+#include <sys/zfs_context.h>
+#include <sys/zfs_znode.h>
+#include <sys/zap.h>
+#include <sys/refcount.h>
+#include <sys/zap_impl.h>
+#include <sys/zap_leaf.h>
+
+int fzap_default_block_shift = 14; /* 16k blocksize */
+
+static void zap_leaf_pageout(dmu_buf_t *db, void *vl);
+static uint64_t zap_allocate_blocks(zap_t *zap, int nblocks);
+
+
+void
+fzap_byteswap(void *vbuf, size_t size)
+{
+	uint64_t block_type;
+
+	block_type = *(uint64_t *)vbuf;
+
+	if (block_type == ZBT_LEAF || block_type == BSWAP_64(ZBT_LEAF))
+		zap_leaf_byteswap(vbuf, size);
+	else {
+		/* it's a ptrtbl block */
+		byteswap_uint64_array(vbuf, size);
+	}
+}
+
+void
+fzap_upgrade(zap_t *zap, dmu_tx_t *tx)
+{
+	dmu_buf_t *db;
+	zap_leaf_t *l;
+	int i;
+	zap_phys_t *zp;
+
+	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
+	zap->zap_ismicro = FALSE;
+
+	(void) dmu_buf_update_user(zap->zap_dbuf, zap, zap,
+	    &zap->zap_f.zap_phys, zap_evict);
+
+	mutex_init(&zap->zap_f.zap_num_entries_mtx, 0, 0, 0);
+	zap->zap_f.zap_block_shift = highbit(zap->zap_dbuf->db_size) - 1;
+
+	zp = zap->zap_f.zap_phys;
+	/*
+	 * explicitly zero it since it might be coming from an
+	 * initialized microzap
+	 */
+	bzero(zap->zap_dbuf->db_data, zap->zap_dbuf->db_size);
+	zp->zap_block_type = ZBT_HEADER;
+	zp->zap_magic = ZAP_MAGIC;
+
+	zp->zap_ptrtbl.zt_shift = ZAP_EMBEDDED_PTRTBL_SHIFT(zap);
+
+	zp->zap_freeblk = 2;		/* block 1 will be the first leaf */
+	zp->zap_num_leafs = 1;
+	zp->zap_num_entries = 0;
+	zp->zap_salt = zap->zap_salt;
+	zp->zap_normflags = zap->zap_normflags;
+
+	/* block 1 will be the first leaf */
+	for (i = 0; i < (1<<zp->zap_ptrtbl.zt_shift); i++)
+		ZAP_EMBEDDED_PTRTBL_ENT(zap, i) = 1;
+
+	/*
+	 * set up block 1 - the first leaf
+	 */
+	VERIFY(0 == dmu_buf_hold(zap->zap_objset, zap->zap_object,
+	    1<<FZAP_BLOCK_SHIFT(zap), FTAG, &db));
+	dmu_buf_will_dirty(db, tx);
+
+	l = kmem_zalloc(sizeof (zap_leaf_t), KM_SLEEP);
+	l->l_dbuf = db;
+	l->l_phys = db->db_data;
+
+	zap_leaf_init(l, zp->zap_normflags != 0);
+
+	kmem_free(l, sizeof (zap_leaf_t));
+	dmu_buf_rele(db, FTAG);
+}
+
+static int
+zap_tryupgradedir(zap_t *zap, dmu_tx_t *tx)
+{
+	if (RW_WRITE_HELD(&zap->zap_rwlock))
+		return (1);
+	if (rw_tryupgrade(&zap->zap_rwlock)) {
+		dmu_buf_will_dirty(zap->zap_dbuf, tx);
+		return (1);
+	}
+	return (0);
+}
+
+/*
+ * Generic routines for dealing with the pointer & cookie tables.
+ */
+
+static int
+zap_table_grow(zap_t *zap, zap_table_phys_t *tbl,
+    void (*transfer_func)(const uint64_t *src, uint64_t *dst, int n),
+    dmu_tx_t *tx)
+{
+	uint64_t b, newblk;
+	dmu_buf_t *db_old, *db_new;
+	int err;
+	int bs = FZAP_BLOCK_SHIFT(zap);
+	int hepb = 1<<(bs-4);
+	/* hepb = half the number of entries in a block */
+
+	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
+	ASSERT(tbl->zt_blk != 0);
+	ASSERT(tbl->zt_numblks > 0);
+
+	if (tbl->zt_nextblk != 0) {
+		newblk = tbl->zt_nextblk;
+	} else {
+		newblk = zap_allocate_blocks(zap, tbl->zt_numblks * 2);
+		tbl->zt_nextblk = newblk;
+		ASSERT3U(tbl->zt_blks_copied, ==, 0);
+		dmu_prefetch(zap->zap_objset, zap->zap_object,
+		    tbl->zt_blk << bs, tbl->zt_numblks << bs);
+	}
+
+	/*
+	 * Copy the ptrtbl from the old to new location.
+	 */
+
+	b = tbl->zt_blks_copied;
+	err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+	    (tbl->zt_blk + b) << bs, FTAG, &db_old);
+	if (err)
+		return (err);
+
+	/* first half of entries in old[b] go to new[2*b+0] */
+	VERIFY(0 == dmu_buf_hold(zap->zap_objset, zap->zap_object,
+	    (newblk + 2*b+0) << bs, FTAG, &db_new));
+	dmu_buf_will_dirty(db_new, tx);
+	transfer_func(db_old->db_data, db_new->db_data, hepb);
+	dmu_buf_rele(db_new, FTAG);
+
+	/* second half of entries in old[b] go to new[2*b+1] */
+	VERIFY(0 == dmu_buf_hold(zap->zap_objset, zap->zap_object,
+	    (newblk + 2*b+1) << bs, FTAG, &db_new));
+	dmu_buf_will_dirty(db_new, tx);
+	transfer_func((uint64_t *)db_old->db_data + hepb,
+	    db_new->db_data, hepb);
+	dmu_buf_rele(db_new, FTAG);
+
+	dmu_buf_rele(db_old, FTAG);
+
+	tbl->zt_blks_copied++;
+
+	dprintf("copied block %llu of %llu\n",
+	    tbl->zt_blks_copied, tbl->zt_numblks);
+
+	if (tbl->zt_blks_copied == tbl->zt_numblks) {
+		(void) dmu_free_range(zap->zap_objset, zap->zap_object,
+		    tbl->zt_blk << bs, tbl->zt_numblks << bs, tx);
+
+		tbl->zt_blk = newblk;
+		tbl->zt_numblks *= 2;
+		tbl->zt_shift++;
+		tbl->zt_nextblk = 0;
+		tbl->zt_blks_copied = 0;
+
+		dprintf("finished; numblocks now %llu (%lluk entries)\n",
+		    tbl->zt_numblks, 1<<(tbl->zt_shift-10));
+	}
+
+	return (0);
+}
+
+static int
+zap_table_store(zap_t *zap, zap_table_phys_t *tbl, uint64_t idx, uint64_t val,
+    dmu_tx_t *tx)
+{
+	int err;
+	uint64_t blk, off;
+	int bs = FZAP_BLOCK_SHIFT(zap);
+	dmu_buf_t *db;
+
+	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
+	ASSERT(tbl->zt_blk != 0);
+
+	dprintf("storing %llx at index %llx\n", val, idx);
+
+	blk = idx >> (bs-3);
+	off = idx & ((1<<(bs-3))-1);
+
+	err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+	    (tbl->zt_blk + blk) << bs, FTAG, &db);
+	if (err)
+		return (err);
+	dmu_buf_will_dirty(db, tx);
+
+	if (tbl->zt_nextblk != 0) {
+		uint64_t idx2 = idx * 2;
+		uint64_t blk2 = idx2 >> (bs-3);
+		uint64_t off2 = idx2 & ((1<<(bs-3))-1);
+		dmu_buf_t *db2;
+
+		err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+		    (tbl->zt_nextblk + blk2) << bs, FTAG, &db2);
+		if (err) {
+			dmu_buf_rele(db, FTAG);
+			return (err);
+		}
+		dmu_buf_will_dirty(db2, tx);
+		((uint64_t *)db2->db_data)[off2] = val;
+		((uint64_t *)db2->db_data)[off2+1] = val;
+		dmu_buf_rele(db2, FTAG);
+	}
+
+	((uint64_t *)db->db_data)[off] = val;
+	dmu_buf_rele(db, FTAG);
+
+	return (0);
+}
+
+static int
+zap_table_load(zap_t *zap, zap_table_phys_t *tbl, uint64_t idx, uint64_t *valp)
+{
+	uint64_t blk, off;
+	int err;
+	dmu_buf_t *db;
+	int bs = FZAP_BLOCK_SHIFT(zap);
+
+	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
+
+	blk = idx >> (bs-3);
+	off = idx & ((1<<(bs-3))-1);
+
+	err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+	    (tbl->zt_blk + blk) << bs, FTAG, &db);
+	if (err)
+		return (err);
+	*valp = ((uint64_t *)db->db_data)[off];
+	dmu_buf_rele(db, FTAG);
+
+	if (tbl->zt_nextblk != 0) {
+		/*
+		 * read the nextblk for the sake of i/o error checking,
+		 * so that zap_table_load() will catch errors for
+		 * zap_table_store.
+		 */
+		blk = (idx*2) >> (bs-3);
+
+		err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+		    (tbl->zt_nextblk + blk) << bs, FTAG, &db);
+		dmu_buf_rele(db, FTAG);
+	}
+	return (err);
+}
+
+/*
+ * Routines for growing the ptrtbl.
+ */
+
+static void
+zap_ptrtbl_transfer(const uint64_t *src, uint64_t *dst, int n)
+{
+	int i;
+	for (i = 0; i < n; i++) {
+		uint64_t lb = src[i];
+		dst[2*i+0] = lb;
+		dst[2*i+1] = lb;
+	}
+}
+
+static int
+zap_grow_ptrtbl(zap_t *zap, dmu_tx_t *tx)
+{
+	/* In case things go horribly wrong. */
+	if (zap->zap_f.zap_phys->zap_ptrtbl.zt_shift >= ZAP_HASHBITS-2)
+		return (ENOSPC);
+
+	if (zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks == 0) {
+		/*
+		 * We are outgrowing the "embedded" ptrtbl (the one
+		 * stored in the header block).  Give it its own entire
+		 * block, which will double the size of the ptrtbl.
+		 */
+		uint64_t newblk;
+		dmu_buf_t *db_new;
+		int err;
+
+		ASSERT3U(zap->zap_f.zap_phys->zap_ptrtbl.zt_shift, ==,
+		    ZAP_EMBEDDED_PTRTBL_SHIFT(zap));
+		ASSERT3U(zap->zap_f.zap_phys->zap_ptrtbl.zt_blk, ==, 0);
+
+		newblk = zap_allocate_blocks(zap, 1);
+		err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+		    newblk << FZAP_BLOCK_SHIFT(zap), FTAG, &db_new);
+		if (err)
+			return (err);
+		dmu_buf_will_dirty(db_new, tx);
+		zap_ptrtbl_transfer(&ZAP_EMBEDDED_PTRTBL_ENT(zap, 0),
+		    db_new->db_data, 1 << ZAP_EMBEDDED_PTRTBL_SHIFT(zap));
+		dmu_buf_rele(db_new, FTAG);
+
+		zap->zap_f.zap_phys->zap_ptrtbl.zt_blk = newblk;
+		zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks = 1;
+		zap->zap_f.zap_phys->zap_ptrtbl.zt_shift++;
+
+		ASSERT3U(1ULL << zap->zap_f.zap_phys->zap_ptrtbl.zt_shift, ==,
+		    zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks <<
+		    (FZAP_BLOCK_SHIFT(zap)-3));
+
+		return (0);
+	} else {
+		return (zap_table_grow(zap, &zap->zap_f.zap_phys->zap_ptrtbl,
+		    zap_ptrtbl_transfer, tx));
+	}
+}
+
+static void
+zap_increment_num_entries(zap_t *zap, int delta, dmu_tx_t *tx)
+{
+	dmu_buf_will_dirty(zap->zap_dbuf, tx);
+	mutex_enter(&zap->zap_f.zap_num_entries_mtx);
+	ASSERT(delta > 0 || zap->zap_f.zap_phys->zap_num_entries >= -delta);
+	zap->zap_f.zap_phys->zap_num_entries += delta;
+	mutex_exit(&zap->zap_f.zap_num_entries_mtx);
+}
+
+static uint64_t
+zap_allocate_blocks(zap_t *zap, int nblocks)
+{
+	uint64_t newblk;
+	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
+	newblk = zap->zap_f.zap_phys->zap_freeblk;
+	zap->zap_f.zap_phys->zap_freeblk += nblocks;
+	return (newblk);
+}
+
+static zap_leaf_t *
+zap_create_leaf(zap_t *zap, dmu_tx_t *tx)
+{
+	void *winner;
+	zap_leaf_t *l = kmem_alloc(sizeof (zap_leaf_t), KM_SLEEP);
+
+	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
+
+	rw_init(&l->l_rwlock, 0, 0, 0);
+	rw_enter(&l->l_rwlock, RW_WRITER);
+	l->l_blkid = zap_allocate_blocks(zap, 1);
+	l->l_dbuf = NULL;
+	l->l_phys = NULL;
+
+	VERIFY(0 == dmu_buf_hold(zap->zap_objset, zap->zap_object,
+	    l->l_blkid << FZAP_BLOCK_SHIFT(zap), NULL, &l->l_dbuf));
+	winner = dmu_buf_set_user(l->l_dbuf, l, &l->l_phys, zap_leaf_pageout);
+	ASSERT(winner == NULL);
+	dmu_buf_will_dirty(l->l_dbuf, tx);
+
+	zap_leaf_init(l, zap->zap_normflags != 0);
+
+	zap->zap_f.zap_phys->zap_num_leafs++;
+
+	return (l);
+}
+
+int
+fzap_count(zap_t *zap, uint64_t *count)
+{
+	ASSERT(!zap->zap_ismicro);
+	mutex_enter(&zap->zap_f.zap_num_entries_mtx); /* unnecessary */
+	*count = zap->zap_f.zap_phys->zap_num_entries;
+	mutex_exit(&zap->zap_f.zap_num_entries_mtx);
+	return (0);
+}
+
+/*
+ * Routines for obtaining zap_leaf_t's
+ */
+
+void
+zap_put_leaf(zap_leaf_t *l)
+{
+	rw_exit(&l->l_rwlock);
+	dmu_buf_rele(l->l_dbuf, NULL);
+}
+
+_NOTE(ARGSUSED(0))
+static void
+zap_leaf_pageout(dmu_buf_t *db, void *vl)
+{
+	zap_leaf_t *l = vl;
+
+	rw_destroy(&l->l_rwlock);
+	kmem_free(l, sizeof (zap_leaf_t));
+}
+
+static zap_leaf_t *
+zap_open_leaf(uint64_t blkid, dmu_buf_t *db)
+{
+	zap_leaf_t *l, *winner;
+
+	ASSERT(blkid != 0);
+
+	l = kmem_alloc(sizeof (zap_leaf_t), KM_SLEEP);
+	rw_init(&l->l_rwlock, 0, 0, 0);
+	rw_enter(&l->l_rwlock, RW_WRITER);
+	l->l_blkid = blkid;
+	l->l_bs = highbit(db->db_size)-1;
+	l->l_dbuf = db;
+	l->l_phys = NULL;
+
+	winner = dmu_buf_set_user(db, l, &l->l_phys, zap_leaf_pageout);
+
+	rw_exit(&l->l_rwlock);
+	if (winner != NULL) {
+		/* someone else set it first */
+		zap_leaf_pageout(NULL, l);
+		l = winner;
+	}
+
+	/*
+	 * lhr_pad was previously used for the next leaf in the leaf
+	 * chain.  There should be no chained leafs (as we have removed
+	 * support for them).
+	 */
+	ASSERT3U(l->l_phys->l_hdr.lh_pad1, ==, 0);
+
+	/*
+	 * There should be more hash entries than there can be
+	 * chunks to put in the hash table
+	 */
+	ASSERT3U(ZAP_LEAF_HASH_NUMENTRIES(l), >, ZAP_LEAF_NUMCHUNKS(l) / 3);
+
+	/* The chunks should begin at the end of the hash table */
+	ASSERT3P(&ZAP_LEAF_CHUNK(l, 0), ==,
+	    &l->l_phys->l_hash[ZAP_LEAF_HASH_NUMENTRIES(l)]);
+
+	/* The chunks should end at the end of the block */
+	ASSERT3U((uintptr_t)&ZAP_LEAF_CHUNK(l, ZAP_LEAF_NUMCHUNKS(l)) -
+	    (uintptr_t)l->l_phys, ==, l->l_dbuf->db_size);
+
+	return (l);
+}
+
+static int
+zap_get_leaf_byblk(zap_t *zap, uint64_t blkid, dmu_tx_t *tx, krw_t lt,
+    zap_leaf_t **lp)
+{
+	dmu_buf_t *db;
+	zap_leaf_t *l;
+	int bs = FZAP_BLOCK_SHIFT(zap);
+	int err;
+
+	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
+
+	err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+	    blkid << bs, NULL, &db);
+	if (err)
+		return (err);
+
+	ASSERT3U(db->db_object, ==, zap->zap_object);
+	ASSERT3U(db->db_offset, ==, blkid << bs);
+	ASSERT3U(db->db_size, ==, 1 << bs);
+	ASSERT(blkid != 0);
+
+	l = dmu_buf_get_user(db);
+
+	if (l == NULL)
+		l = zap_open_leaf(blkid, db);
+
+	rw_enter(&l->l_rwlock, lt);
+	/*
+	 * Must lock before dirtying, otherwise l->l_phys could change,
+	 * causing ASSERT below to fail.
+	 */
+	if (lt == RW_WRITER)
+		dmu_buf_will_dirty(db, tx);
+	ASSERT3U(l->l_blkid, ==, blkid);
+	ASSERT3P(l->l_dbuf, ==, db);
+	ASSERT3P(l->l_phys, ==, l->l_dbuf->db_data);
+	ASSERT3U(l->l_phys->l_hdr.lh_block_type, ==, ZBT_LEAF);
+	ASSERT3U(l->l_phys->l_hdr.lh_magic, ==, ZAP_LEAF_MAGIC);
+
+	*lp = l;
+	return (0);
+}
+
+static int
+zap_idx_to_blk(zap_t *zap, uint64_t idx, uint64_t *valp)
+{
+	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
+
+	if (zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks == 0) {
+		ASSERT3U(idx, <,
+		    (1ULL << zap->zap_f.zap_phys->zap_ptrtbl.zt_shift));
+		*valp = ZAP_EMBEDDED_PTRTBL_ENT(zap, idx);
+		return (0);
+	} else {
+		return (zap_table_load(zap, &zap->zap_f.zap_phys->zap_ptrtbl,
+		    idx, valp));
+	}
+}
+
+static int
+zap_set_idx_to_blk(zap_t *zap, uint64_t idx, uint64_t blk, dmu_tx_t *tx)
+{
+	ASSERT(tx != NULL);
+	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
+
+	if (zap->zap_f.zap_phys->zap_ptrtbl.zt_blk == 0) {
+		ZAP_EMBEDDED_PTRTBL_ENT(zap, idx) = blk;
+		return (0);
+	} else {
+		return (zap_table_store(zap, &zap->zap_f.zap_phys->zap_ptrtbl,
+		    idx, blk, tx));
+	}
+}
+
+static int
+zap_deref_leaf(zap_t *zap, uint64_t h, dmu_tx_t *tx, krw_t lt, zap_leaf_t **lp)
+{
+	uint64_t idx, blk;
+	int err;
+
+	ASSERT(zap->zap_dbuf == NULL ||
+	    zap->zap_f.zap_phys == zap->zap_dbuf->db_data);
+	ASSERT3U(zap->zap_f.zap_phys->zap_magic, ==, ZAP_MAGIC);
+	idx = ZAP_HASH_IDX(h, zap->zap_f.zap_phys->zap_ptrtbl.zt_shift);
+	err = zap_idx_to_blk(zap, idx, &blk);
+	if (err != 0)
+		return (err);
+	err = zap_get_leaf_byblk(zap, blk, tx, lt, lp);
+
+	ASSERT(err || ZAP_HASH_IDX(h, (*lp)->l_phys->l_hdr.lh_prefix_len) ==
+	    (*lp)->l_phys->l_hdr.lh_prefix);
+	return (err);
+}
+
+static int
+zap_expand_leaf(zap_name_t *zn, zap_leaf_t *l, dmu_tx_t *tx, zap_leaf_t **lp)
+{
+	zap_t *zap = zn->zn_zap;
+	uint64_t hash = zn->zn_hash;
+	zap_leaf_t *nl;
+	int prefix_diff, i, err;
+	uint64_t sibling;
+	int old_prefix_len = l->l_phys->l_hdr.lh_prefix_len;
+
+	ASSERT3U(old_prefix_len, <=, zap->zap_f.zap_phys->zap_ptrtbl.zt_shift);
+	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
+
+	ASSERT3U(ZAP_HASH_IDX(hash, old_prefix_len), ==,
+	    l->l_phys->l_hdr.lh_prefix);
+
+	if (zap_tryupgradedir(zap, tx) == 0 ||
+	    old_prefix_len == zap->zap_f.zap_phys->zap_ptrtbl.zt_shift) {
+		/* We failed to upgrade, or need to grow the pointer table */
+		objset_t *os = zap->zap_objset;
+		uint64_t object = zap->zap_object;
+
+		zap_put_leaf(l);
+		zap_unlockdir(zap);
+		err = zap_lockdir(os, object, tx, RW_WRITER,
+		    FALSE, FALSE, &zn->zn_zap);
+		zap = zn->zn_zap;
+		if (err)
+			return (err);
+		ASSERT(!zap->zap_ismicro);
+
+		while (old_prefix_len ==
+		    zap->zap_f.zap_phys->zap_ptrtbl.zt_shift) {
+			err = zap_grow_ptrtbl(zap, tx);
+			if (err)
+				return (err);
+		}
+
+		err = zap_deref_leaf(zap, hash, tx, RW_WRITER, &l);
+		if (err)
+			return (err);
+
+		if (l->l_phys->l_hdr.lh_prefix_len != old_prefix_len) {
+			/* it split while our locks were down */
+			*lp = l;
+			return (0);
+		}
+	}
+	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
+	ASSERT3U(old_prefix_len, <, zap->zap_f.zap_phys->zap_ptrtbl.zt_shift);
+	ASSERT3U(ZAP_HASH_IDX(hash, old_prefix_len), ==,
+	    l->l_phys->l_hdr.lh_prefix);
+
+	prefix_diff = zap->zap_f.zap_phys->zap_ptrtbl.zt_shift -
+	    (old_prefix_len + 1);
+	sibling = (ZAP_HASH_IDX(hash, old_prefix_len + 1) | 1) << prefix_diff;
+
+	/* check for i/o errors before doing zap_leaf_split */
+	for (i = 0; i < (1ULL<<prefix_diff); i++) {
+		uint64_t blk;
+		err = zap_idx_to_blk(zap, sibling+i, &blk);
+		if (err)
+			return (err);
+		ASSERT3U(blk, ==, l->l_blkid);
+	}
+
+	nl = zap_create_leaf(zap, tx);
+	zap_leaf_split(l, nl, zap->zap_normflags != 0);
+
+	/* set sibling pointers */
+	for (i = 0; i < (1ULL<<prefix_diff); i++) {
+		err = zap_set_idx_to_blk(zap, sibling+i, nl->l_blkid, tx);
+		ASSERT3U(err, ==, 0); /* we checked for i/o errors above */
+	}
+
+	if (hash & (1ULL << (64 - l->l_phys->l_hdr.lh_prefix_len))) {
+		/* we want the sibling */
+		zap_put_leaf(l);
+		*lp = nl;
+	} else {
+		zap_put_leaf(nl);
+		*lp = l;
+	}
+
+	return (0);
+}
+
+static void
+zap_put_leaf_maybe_grow_ptrtbl(zap_name_t *zn, zap_leaf_t *l, dmu_tx_t *tx)
+{
+	zap_t *zap = zn->zn_zap;
+	int shift = zap->zap_f.zap_phys->zap_ptrtbl.zt_shift;
+	int leaffull = (l->l_phys->l_hdr.lh_prefix_len == shift &&
+	    l->l_phys->l_hdr.lh_nfree < ZAP_LEAF_LOW_WATER);
+
+	zap_put_leaf(l);
+
+	if (leaffull || zap->zap_f.zap_phys->zap_ptrtbl.zt_nextblk) {
+		int err;
+
+		/*
+		 * We are in the middle of growing the pointer table, or
+		 * this leaf will soon make us grow it.
+		 */
+		if (zap_tryupgradedir(zap, tx) == 0) {
+			objset_t *os = zap->zap_objset;
+			uint64_t zapobj = zap->zap_object;
+
+			zap_unlockdir(zap);
+			err = zap_lockdir(os, zapobj, tx,
+			    RW_WRITER, FALSE, FALSE, &zn->zn_zap);
+			zap = zn->zn_zap;
+			if (err)
+				return;
+		}
+
+		/* could have finished growing while our locks were down */
+		if (zap->zap_f.zap_phys->zap_ptrtbl.zt_shift == shift)
+			(void) zap_grow_ptrtbl(zap, tx);
+	}
+}
+
+
+static int
+fzap_checksize(const char *name, uint64_t integer_size, uint64_t num_integers)
+{
+	if (name && strlen(name) > ZAP_MAXNAMELEN)
+		return (E2BIG);
+
+	/* Only integer sizes supported by C */
+	switch (integer_size) {
+	case 1:
+	case 2:
+	case 4:
+	case 8:
+		break;
+	default:
+		return (EINVAL);
+	}
+
+	if (integer_size * num_integers > ZAP_MAXVALUELEN)
+		return (E2BIG);
+
+	return (0);
+}
+
+/*
+ * Routines for manipulating attributes.
+ */
+int
+fzap_lookup(zap_name_t *zn,
+    uint64_t integer_size, uint64_t num_integers, void *buf,
+    char *realname, int rn_len, boolean_t *ncp)
+{
+	zap_leaf_t *l;
+	int err;
+	zap_entry_handle_t zeh;
+
+	err = fzap_checksize(zn->zn_name_orij, integer_size, num_integers);
+	if (err != 0)
+		return (err);
+
+	err = zap_deref_leaf(zn->zn_zap, zn->zn_hash, NULL, RW_READER, &l);
+	if (err != 0)
+		return (err);
+	err = zap_leaf_lookup(l, zn, &zeh);
+	if (err == 0) {
+		err = zap_entry_read(&zeh, integer_size, num_integers, buf);
+		(void) zap_entry_read_name(&zeh, rn_len, realname);
+		if (ncp) {
+			*ncp = zap_entry_normalization_conflict(&zeh,
+			    zn, NULL, zn->zn_zap);
+		}
+	}
+
+	zap_put_leaf(l);
+	return (err);
+}
+
+int
+fzap_add_cd(zap_name_t *zn,
+    uint64_t integer_size, uint64_t num_integers,
+    const void *val, uint32_t cd, dmu_tx_t *tx)
+{
+	zap_leaf_t *l;
+	int err;
+	zap_entry_handle_t zeh;
+	zap_t *zap = zn->zn_zap;
+
+	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
+	ASSERT(!zap->zap_ismicro);
+	ASSERT(fzap_checksize(zn->zn_name_orij,
+	    integer_size, num_integers) == 0);
+
+	err = zap_deref_leaf(zap, zn->zn_hash, tx, RW_WRITER, &l);
+	if (err != 0)
+		return (err);
+retry:
+	err = zap_leaf_lookup(l, zn, &zeh);
+	if (err == 0) {
+		err = EEXIST;
+		goto out;
+	}
+	if (err != ENOENT)
+		goto out;
+
+	err = zap_entry_create(l, zn->zn_name_orij, zn->zn_hash, cd,
+	    integer_size, num_integers, val, &zeh);
+
+	if (err == 0) {
+		zap_increment_num_entries(zap, 1, tx);
+	} else if (err == EAGAIN) {
+		err = zap_expand_leaf(zn, l, tx, &l);
+		zap = zn->zn_zap;	/* zap_expand_leaf() may change zap */
+		if (err == 0)
+			goto retry;
+	}
+
+out:
+	if (zap != NULL)
+		zap_put_leaf_maybe_grow_ptrtbl(zn, l, tx);
+	return (err);
+}
+
+int
+fzap_add(zap_name_t *zn,
+    uint64_t integer_size, uint64_t num_integers,
+    const void *val, dmu_tx_t *tx)
+{
+	int err = fzap_checksize(zn->zn_name_orij, integer_size, num_integers);
+	if (err != 0)
+		return (err);
+
+	return (fzap_add_cd(zn, integer_size, num_integers,
+	    val, ZAP_MAXCD, tx));
+}
+
+int
+fzap_update(zap_name_t *zn,
+    int integer_size, uint64_t num_integers, const void *val, dmu_tx_t *tx)
+{
+	zap_leaf_t *l;
+	int err, create;
+	zap_entry_handle_t zeh;
+	zap_t *zap = zn->zn_zap;
+
+	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
+	err = fzap_checksize(zn->zn_name_orij, integer_size, num_integers);
+	if (err != 0)
+		return (err);
+
+	err = zap_deref_leaf(zap, zn->zn_hash, tx, RW_WRITER, &l);
+	if (err != 0)
+		return (err);
+retry:
+	err = zap_leaf_lookup(l, zn, &zeh);
+	create = (err == ENOENT);
+	ASSERT(err == 0 || err == ENOENT);
+
+	if (create) {
+		err = zap_entry_create(l, zn->zn_name_orij, zn->zn_hash,
+		    ZAP_MAXCD, integer_size, num_integers, val, &zeh);
+		if (err == 0)
+			zap_increment_num_entries(zap, 1, tx);
+	} else {
+		err = zap_entry_update(&zeh, integer_size, num_integers, val);
+	}
+
+	if (err == EAGAIN) {
+		err = zap_expand_leaf(zn, l, tx, &l);
+		zap = zn->zn_zap;	/* zap_expand_leaf() may change zap */
+		if (err == 0)
+			goto retry;
+	}
+
+	if (zap != NULL)
+		zap_put_leaf_maybe_grow_ptrtbl(zn, l, tx);
+	return (err);
+}
+
+int
+fzap_length(zap_name_t *zn,
+    uint64_t *integer_size, uint64_t *num_integers)
+{
+	zap_leaf_t *l;
+	int err;
+	zap_entry_handle_t zeh;
+
+	err = zap_deref_leaf(zn->zn_zap, zn->zn_hash, NULL, RW_READER, &l);
+	if (err != 0)
+		return (err);
+	err = zap_leaf_lookup(l, zn, &zeh);
+	if (err != 0)
+		goto out;
+
+	if (integer_size)
+		*integer_size = zeh.zeh_integer_size;
+	if (num_integers)
+		*num_integers = zeh.zeh_num_integers;
+out:
+	zap_put_leaf(l);
+	return (err);
+}
+
+int
+fzap_remove(zap_name_t *zn, dmu_tx_t *tx)
+{
+	zap_leaf_t *l;
+	int err;
+	zap_entry_handle_t zeh;
+
+	err = zap_deref_leaf(zn->zn_zap, zn->zn_hash, tx, RW_WRITER, &l);
+	if (err != 0)
+		return (err);
+	err = zap_leaf_lookup(l, zn, &zeh);
+	if (err == 0) {
+		zap_entry_remove(&zeh);
+		zap_increment_num_entries(zn->zn_zap, -1, tx);
+	}
+	zap_put_leaf(l);
+	return (err);
+}
+
+/*
+ * Helper functions for consumers.
+ */
+
+int
+zap_value_search(objset_t *os, uint64_t zapobj, uint64_t value, uint64_t mask,
+    char *name)
+{
+	zap_cursor_t zc;
+	zap_attribute_t *za;
+	int err;
+
+	if (mask == 0)
+		mask = -1ULL;
+
+	za = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
+	for (zap_cursor_init(&zc, os, zapobj);
+	    (err = zap_cursor_retrieve(&zc, za)) == 0;
+	    zap_cursor_advance(&zc)) {
+		if ((za->za_first_integer & mask) == (value & mask)) {
+			(void) strcpy(name, za->za_name);
+			break;
+		}
+	}
+	zap_cursor_fini(&zc);
+	kmem_free(za, sizeof (zap_attribute_t));
+	return (err);
+}
+
+int
+zap_join(objset_t *os, uint64_t fromobj, uint64_t intoobj, dmu_tx_t *tx)
+{
+	zap_cursor_t zc;
+	zap_attribute_t za;
+	int err;
+
+	for (zap_cursor_init(&zc, os, fromobj);
+	    zap_cursor_retrieve(&zc, &za) == 0;
+	    (void) zap_cursor_advance(&zc)) {
+		if (za.za_integer_length != 8 || za.za_num_integers != 1)
+			return (EINVAL);
+		err = zap_add(os, intoobj, za.za_name,
+		    8, 1, &za.za_first_integer, tx);
+		if (err)
+			return (err);
+	}
+	zap_cursor_fini(&zc);
+	return (0);
+}
+
+int
+zap_add_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx)
+{
+	char name[20];
+
+	(void) snprintf(name, sizeof (name), "%llx", (longlong_t)value);
+	return (zap_add(os, obj, name, 8, 1, &value, tx));
+}
+
+int
+zap_remove_int(objset_t *os, uint64_t obj, uint64_t value, dmu_tx_t *tx)
+{
+	char name[20];
+
+	(void) snprintf(name, sizeof (name), "%llx", (longlong_t)value);
+	return (zap_remove(os, obj, name, tx));
+}
+
+int
+zap_lookup_int(objset_t *os, uint64_t obj, uint64_t value)
+{
+	char name[20];
+
+	(void) snprintf(name, sizeof (name), "%llx", (longlong_t)value);
+	return (zap_lookup(os, obj, name, 8, 1, &value));
+}
+
+/*
+ * Routines for iterating over the attributes.
+ */
+
+int
+fzap_cursor_retrieve(zap_t *zap, zap_cursor_t *zc, zap_attribute_t *za)
+{
+	int err = ENOENT;
+	zap_entry_handle_t zeh;
+	zap_leaf_t *l;
+
+	/* retrieve the next entry at or after zc_hash/zc_cd */
+	/* if no entry, return ENOENT */
+
+	if (zc->zc_leaf &&
+	    (ZAP_HASH_IDX(zc->zc_hash,
+	    zc->zc_leaf->l_phys->l_hdr.lh_prefix_len) !=
+	    zc->zc_leaf->l_phys->l_hdr.lh_prefix)) {
+		rw_enter(&zc->zc_leaf->l_rwlock, RW_READER);
+		zap_put_leaf(zc->zc_leaf);
+		zc->zc_leaf = NULL;
+	}
+
+again:
+	if (zc->zc_leaf == NULL) {
+		err = zap_deref_leaf(zap, zc->zc_hash, NULL, RW_READER,
+		    &zc->zc_leaf);
+		if (err != 0)
+			return (err);
+	} else {
+		rw_enter(&zc->zc_leaf->l_rwlock, RW_READER);
+	}
+	l = zc->zc_leaf;
+
+	err = zap_leaf_lookup_closest(l, zc->zc_hash, zc->zc_cd, &zeh);
+
+	if (err == ENOENT) {
+		uint64_t nocare =
+		    (1ULL << (64 - l->l_phys->l_hdr.lh_prefix_len)) - 1;
+		zc->zc_hash = (zc->zc_hash & ~nocare) + nocare + 1;
+		zc->zc_cd = 0;
+		if (l->l_phys->l_hdr.lh_prefix_len == 0 || zc->zc_hash == 0) {
+			zc->zc_hash = -1ULL;
+		} else {
+			zap_put_leaf(zc->zc_leaf);
+			zc->zc_leaf = NULL;
+			goto again;
+		}
+	}
+
+	if (err == 0) {
+		zc->zc_hash = zeh.zeh_hash;
+		zc->zc_cd = zeh.zeh_cd;
+		za->za_integer_length = zeh.zeh_integer_size;
+		za->za_num_integers = zeh.zeh_num_integers;
+		if (zeh.zeh_num_integers == 0) {
+			za->za_first_integer = 0;
+		} else {
+			err = zap_entry_read(&zeh, 8, 1, &za->za_first_integer);
+			ASSERT(err == 0 || err == EOVERFLOW);
+		}
+		err = zap_entry_read_name(&zeh,
+		    sizeof (za->za_name), za->za_name);
+		ASSERT(err == 0);
+
+		za->za_normalization_conflict =
+		    zap_entry_normalization_conflict(&zeh,
+		    NULL, za->za_name, zap);
+	}
+	rw_exit(&zc->zc_leaf->l_rwlock);
+	return (err);
+}
+
+
+static void
+zap_stats_ptrtbl(zap_t *zap, uint64_t *tbl, int len, zap_stats_t *zs)
+{
+	int i, err;
+	uint64_t lastblk = 0;
+
+	/*
+	 * NB: if a leaf has more pointers than an entire ptrtbl block
+	 * can hold, then it'll be accounted for more than once, since
+	 * we won't have lastblk.
+	 */
+	for (i = 0; i < len; i++) {
+		zap_leaf_t *l;
+
+		if (tbl[i] == lastblk)
+			continue;
+		lastblk = tbl[i];
+
+		err = zap_get_leaf_byblk(zap, tbl[i], NULL, RW_READER, &l);
+		if (err == 0) {
+			zap_leaf_stats(zap, l, zs);
+			zap_put_leaf(l);
+		}
+	}
+}
+
+void
+fzap_get_stats(zap_t *zap, zap_stats_t *zs)
+{
+	int bs = FZAP_BLOCK_SHIFT(zap);
+	zs->zs_blocksize = 1ULL << bs;
+
+	/*
+	 * Set zap_phys_t fields
+	 */
+	zs->zs_num_leafs = zap->zap_f.zap_phys->zap_num_leafs;
+	zs->zs_num_entries = zap->zap_f.zap_phys->zap_num_entries;
+	zs->zs_num_blocks = zap->zap_f.zap_phys->zap_freeblk;
+	zs->zs_block_type = zap->zap_f.zap_phys->zap_block_type;
+	zs->zs_magic = zap->zap_f.zap_phys->zap_magic;
+	zs->zs_salt = zap->zap_f.zap_phys->zap_salt;
+
+	/*
+	 * Set zap_ptrtbl fields
+	 */
+	zs->zs_ptrtbl_len = 1ULL << zap->zap_f.zap_phys->zap_ptrtbl.zt_shift;
+	zs->zs_ptrtbl_nextblk = zap->zap_f.zap_phys->zap_ptrtbl.zt_nextblk;
+	zs->zs_ptrtbl_blks_copied =
+	    zap->zap_f.zap_phys->zap_ptrtbl.zt_blks_copied;
+	zs->zs_ptrtbl_zt_blk = zap->zap_f.zap_phys->zap_ptrtbl.zt_blk;
+	zs->zs_ptrtbl_zt_numblks = zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks;
+	zs->zs_ptrtbl_zt_shift = zap->zap_f.zap_phys->zap_ptrtbl.zt_shift;
+
+	if (zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks == 0) {
+		/* the ptrtbl is entirely in the header block. */
+		zap_stats_ptrtbl(zap, &ZAP_EMBEDDED_PTRTBL_ENT(zap, 0),
+		    1 << ZAP_EMBEDDED_PTRTBL_SHIFT(zap), zs);
+	} else {
+		int b;
+
+		dmu_prefetch(zap->zap_objset, zap->zap_object,
+		    zap->zap_f.zap_phys->zap_ptrtbl.zt_blk << bs,
+		    zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks << bs);
+
+		for (b = 0; b < zap->zap_f.zap_phys->zap_ptrtbl.zt_numblks;
+		    b++) {
+			dmu_buf_t *db;
+			int err;
+
+			err = dmu_buf_hold(zap->zap_objset, zap->zap_object,
+			    (zap->zap_f.zap_phys->zap_ptrtbl.zt_blk + b) << bs,
+			    FTAG, &db);
+			if (err == 0) {
+				zap_stats_ptrtbl(zap, db->db_data,
+				    1<<(bs-3), zs);
+				dmu_buf_rele(db, FTAG);
+			}
+		}
+	}
+}