Illumos #2882, #2883, #2900

2882 implement libzfs_core
2883 changing "canmount" property to "on" should not always remount dataset
2900 "zfs snapshot" should be able to create multiple, arbitrary snapshots at once

Reviewed by: George Wilson <[email protected]>
Reviewed by: Chris Siden <[email protected]>
Reviewed by: Garrett D'Amore <[email protected]>
Reviewed by: Bill Pijewski <[email protected]>
Reviewed by: Dan Kruchinin <[email protected]>
Approved by: Eric Schrock <[email protected]>

References:
  https://www.illumos.org/issues/2882
  https://www.illumos.org/issues/2883
  https://www.illumos.org/issues/2900
  illumos/illumos-gate@4445fffbbb1ea25fd0e9ea68b9380dd7a6709025

Ported-by: Tim Chase <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #1293

Porting notes:

WARNING: This patch changes the user/kernel ABI.  That means that
the zfs/zpool utilities built from master are NOT compatible with
the 0.6.2 kernel modules.  Ensure you load the matching kernel
modules from master after updating the utilities.  Otherwise the
zfs/zpool commands will be unable to interact with your pool and
you will see errors similar to the following:

  $ zpool list
  failed to read pool configuration: bad address
  no pools available

  $ zfs list
  no datasets available

Add zvol minor device creation to the new zfs_snapshot_nvl function.

Remove the logging of the "release" operation in
dsl_dataset_user_release_sync().  The logging caused a null dereference
because ds->ds_dir is zeroed in dsl_dataset_destroy_sync() and the
logging functions try to get the ds name via the dsl_dataset_name()
function. I've got no idea why this particular code would have worked
in Illumos.  This code has subsequently been completely reworked in
Illumos commit 3b2aab1 (3464 zfs synctask code needs restructuring).

Squash some "may be used uninitialized" warning/erorrs.

Fix some printf format warnings for %lld and %llu.

Apply a few spa_writeable() changes that were made to Illumos in
illumos/illumos-gate.git@cd1c8b8 as part of the 3112, 3113, 3114 and
3115 fixes.

Add a missing call to fnvlist_free(nvl) in log_internal() that was added
in Illumos to fix issue 3085 but couldn't be ported to ZoL at the time
(zfsonlinux/zfs@9e11c73) because it depended on future work.

1 files changed, 185 insertions, 125 deletions

diff --git a/module/zfs/dmu_objset.c b/module/zfs/dmu_objset.c
index 52d55d566..0f07a4cc9 100644
--- a/module/zfs/dmu_objset.c
+++ b/module/zfs/dmu_objset.c
@@ -21,6 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
+ * Copyright (c) 2012 by Delphix. All rights reserved.
  */
 
 /* Portions Copyright 2010 Robert Milkowski */
@@ -525,9 +526,10 @@ dmu_objset_evict_dbufs(objset_t *os)
 void
 dmu_objset_evict(objset_t *os)
 {
-	dsl_dataset_t *ds = os->os_dsl_dataset;
 	int t;
 
+	dsl_dataset_t *ds = os->os_dsl_dataset;
+
 	for (t = 0; t < TXG_SIZE; t++)
 		ASSERT(!dmu_objset_is_dirty(os, t));
 
@@ -698,30 +700,33 @@ dmu_objset_create_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 	spa_t *spa = dd->dd_pool->dp_spa;
 	struct oscarg *oa = arg2;
 	uint64_t obj;
+	dsl_dataset_t *ds;
+	blkptr_t *bp;
 
 	ASSERT(dmu_tx_is_syncing(tx));
 
 	obj = dsl_dataset_create_sync(dd, oa->lastname,
 	    oa->clone_origin, oa->flags, oa->cr, tx);
 
-	if (oa->clone_origin == NULL) {
-		dsl_pool_t *dp = dd->dd_pool;
-		dsl_dataset_t *ds;
-		blkptr_t *bp;
-		objset_t *os;
-
-		VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, obj, FTAG, &ds));
-		bp = dsl_dataset_get_blkptr(ds);
-		ASSERT(BP_IS_HOLE(bp));
-
-		os = dmu_objset_create_impl(spa, ds, bp, oa->type, tx);
+	VERIFY3U(0, ==, dsl_dataset_hold_obj(dd->dd_pool, obj, FTAG, &ds));
+	bp = dsl_dataset_get_blkptr(ds);
+	if (BP_IS_HOLE(bp)) {
+		objset_t *os =
+		    dmu_objset_create_impl(spa, ds, bp, oa->type, tx);
 
 		if (oa->userfunc)
 			oa->userfunc(os, oa->userarg, oa->cr, tx);
-		dsl_dataset_rele(ds, FTAG);
 	}
 
-	spa_history_log_internal(LOG_DS_CREATE, spa, tx, "dataset = %llu", obj);
+	if (oa->clone_origin == NULL) {
+		spa_history_log_internal_ds(ds, "create", tx, "");
+	} else {
+		char namebuf[MAXNAMELEN];
+		dsl_dataset_name(oa->clone_origin, namebuf);
+		spa_history_log_internal_ds(ds, "clone", tx,
+		    "origin=%s (%llu)", namebuf, oa->clone_origin->ds_object);
+	}
+	dsl_dataset_rele(ds, FTAG);
 }
 
 int
@@ -798,34 +803,40 @@ dmu_objset_destroy(const char *name, boolean_t defer)
 	return (error);
 }
 
-struct snaparg {
-	dsl_sync_task_group_t *dstg;
-	char *snapname;
-	char *htag;
-	char failed[MAXPATHLEN];
-	boolean_t recursive;
-	boolean_t needsuspend;
-	boolean_t temporary;
-	nvlist_t *props;
-	struct dsl_ds_holdarg *ha;	/* only needed in the temporary case */
-	dsl_dataset_t *newds;
-};
+typedef struct snapallarg {
+	dsl_sync_task_group_t *saa_dstg;
+	boolean_t saa_needsuspend;
+	nvlist_t *saa_props;
+
+	/* the following are used only if 'temporary' is set: */
+	boolean_t saa_temporary;
+	const char *saa_htag;
+	struct dsl_ds_holdarg *saa_ha;
+	dsl_dataset_t *saa_newds;
+} snapallarg_t;
+
+typedef struct snaponearg {
+	const char *soa_longname; /* long snap name */
+	const char *soa_snapname; /* short snap name */
+	snapallarg_t *soa_saa;
+} snaponearg_t;
 
 static int
 snapshot_check(void *arg1, void *arg2, dmu_tx_t *tx)
 {
 	objset_t *os = arg1;
-	struct snaparg *sn = arg2;
+	snaponearg_t *soa = arg2;
+	snapallarg_t *saa = soa->soa_saa;
 	int error;
 
 	/* The props have already been checked by zfs_check_userprops(). */
 
 	error = dsl_dataset_snapshot_check(os->os_dsl_dataset,
-	    sn->snapname, tx);
+	    soa->soa_snapname, tx);
 	if (error)
 		return (error);
 
-	if (sn->temporary) {
+	if (saa->saa_temporary) {
 		/*
 		 * Ideally we would just call
 		 * dsl_dataset_user_hold_check() and
@@ -843,12 +854,13 @@ snapshot_check(void *arg1, void *arg2, dmu_tx_t *tx)
 		 * Not checking number of tags because the tag will be
 		 * unique, as it will be the only tag.
 		 */
-		if (strlen(sn->htag) + MAX_TAG_PREFIX_LEN >= MAXNAMELEN)
+		if (strlen(saa->saa_htag) + MAX_TAG_PREFIX_LEN >= MAXNAMELEN)
 			return (E2BIG);
 
-		sn->ha = kmem_alloc(sizeof(struct dsl_ds_holdarg), KM_PUSHPAGE);
-		sn->ha->temphold = B_TRUE;
-		sn->ha->htag = sn->htag;
+		saa->saa_ha = kmem_alloc(sizeof (struct dsl_ds_holdarg),
+		    KM_PUSHPAGE);
+		saa->saa_ha->temphold = B_TRUE;
+		saa->saa_ha->htag = saa->saa_htag;
 	}
 	return (error);
 }
@@ -858,24 +870,25 @@ snapshot_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 {
 	objset_t *os = arg1;
 	dsl_dataset_t *ds = os->os_dsl_dataset;
-	struct snaparg *sn = arg2;
+	snaponearg_t *soa = arg2;
+	snapallarg_t *saa = soa->soa_saa;
 
-	dsl_dataset_snapshot_sync(ds, sn->snapname, tx);
+	dsl_dataset_snapshot_sync(ds, soa->soa_snapname, tx);
 
-	if (sn->props) {
+	if (saa->saa_props != NULL) {
 		dsl_props_arg_t pa;
-		pa.pa_props = sn->props;
+		pa.pa_props = saa->saa_props;
 		pa.pa_source = ZPROP_SRC_LOCAL;
 		dsl_props_set_sync(ds->ds_prev, &pa, tx);
 	}
 
-	if (sn->temporary) {
+	if (saa->saa_temporary) {
 		struct dsl_ds_destroyarg da;
 
-		dsl_dataset_user_hold_sync(ds->ds_prev, sn->ha, tx);
-		kmem_free(sn->ha, sizeof (struct dsl_ds_holdarg));
-		sn->ha = NULL;
-		sn->newds = ds->ds_prev;
+		dsl_dataset_user_hold_sync(ds->ds_prev, saa->saa_ha, tx);
+		kmem_free(saa->saa_ha, sizeof (struct dsl_ds_holdarg));
+		saa->saa_ha = NULL;
+		saa->saa_newds = ds->ds_prev;
 
 		da.ds = ds->ds_prev;
 		da.defer = B_TRUE;
@@ -884,135 +897,182 @@ snapshot_sync(void *arg1, void *arg2, dmu_tx_t *tx)
 }
 
 static int
-dmu_objset_snapshot_one(const char *name, void *arg)
+snapshot_one_impl(const char *snapname, void *arg)
 {
-	struct snaparg *sn = arg;
+	char *fsname;
+	snapallarg_t *saa = arg;
+	snaponearg_t *soa;
 	objset_t *os;
 	int err;
-	char *cp;
 
-	/*
-	 * If the objset starts with a '%', then ignore it unless it was
-	 * explicitly named (ie, not recursive).  These hidden datasets
-	 * are always inconsistent, and by not opening them here, we can
-	 * avoid a race with dsl_dir_destroy_check().
-	 */
-	cp = strrchr(name, '/');
-	if (cp && cp[1] == '%' && sn->recursive)
-		return (0);
+	fsname = kmem_zalloc(MAXPATHLEN, KM_PUSHPAGE);
+	(void) strlcpy(fsname, snapname, MAXPATHLEN);
+	strchr(fsname, '@')[0] = '\0';
 
-	(void) strcpy(sn->failed, name);
-
-	/*
-	 * Check permissions if we are doing a recursive snapshot.  The
-	 * permission checks for the starting dataset have already been
-	 * performed in zfs_secpolicy_snapshot()
-	 */
-	if (sn->recursive && (err = zfs_secpolicy_snapshot_perms(name, CRED())))
-		return (err);
-
-	err = dmu_objset_hold(name, sn, &os);
+	err = dmu_objset_hold(fsname, saa, &os);
+	kmem_free(fsname, MAXPATHLEN);
 	if (err != 0)
 		return (err);
 
 	/*
 	 * If the objset is in an inconsistent state (eg, in the process
-	 * of being destroyed), don't snapshot it.  As with %hidden
-	 * datasets, we return EBUSY if this name was explicitly
-	 * requested (ie, not recursive), and otherwise ignore it.
+	 * of being destroyed), don't snapshot it.
 	 */
 	if (os->os_dsl_dataset->ds_phys->ds_flags & DS_FLAG_INCONSISTENT) {
-		dmu_objset_rele(os, sn);
-		return (sn->recursive ? 0 : EBUSY);
+		dmu_objset_rele(os, saa);
+		return (EBUSY);
 	}
 
-	if (sn->needsuspend) {
+	if (saa->saa_needsuspend) {
 		err = zil_suspend(dmu_objset_zil(os));
 		if (err) {
-			dmu_objset_rele(os, sn);
+			dmu_objset_rele(os, saa);
 			return (err);
 		}
 	}
-	dsl_sync_task_create(sn->dstg, snapshot_check, snapshot_sync,
-	    os, sn, 3);
+
+	soa = kmem_zalloc(sizeof (*soa), KM_PUSHPAGE);
+	soa->soa_saa = saa;
+	soa->soa_longname = snapname;
+	soa->soa_snapname = strchr(snapname, '@') + 1;
+
+	dsl_sync_task_create(saa->saa_dstg, snapshot_check, snapshot_sync,
+	    os, soa, 3);
 
 	return (0);
 }
 
+/*
+ * The snapshots must all be in the same pool.
+ */
 int
-dmu_objset_snapshot(char *fsname, char *snapname, char *tag,
-    nvlist_t *props, boolean_t recursive, boolean_t temporary, int cleanup_fd)
+dmu_objset_snapshot(nvlist_t *snaps, nvlist_t *props, nvlist_t *errors)
 {
 	dsl_sync_task_t *dst;
-	struct snaparg *sn;
+	snapallarg_t saa = { 0 };
 	spa_t *spa;
-	minor_t minor;
+	int rv = 0;
 	int err;
+	nvpair_t *pair;
 
-	sn = kmem_alloc(sizeof (struct snaparg), KM_SLEEP);
-	(void) strcpy(sn->failed, fsname);
+	pair = nvlist_next_nvpair(snaps, NULL);
+	if (pair == NULL)
+		return (0);
 
-	err = spa_open(fsname, &spa, FTAG);
-	if (err) {
-		kmem_free(sn, sizeof (struct snaparg));
+	err = spa_open(nvpair_name(pair), &spa, FTAG);
+	if (err)
 		return (err);
+	saa.saa_dstg = dsl_sync_task_group_create(spa_get_dsl(spa));
+	saa.saa_props = props;
+	saa.saa_needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
+
+	for (pair = nvlist_next_nvpair(snaps, NULL); pair != NULL;
+	    pair = nvlist_next_nvpair(snaps, pair)) {
+		err = snapshot_one_impl(nvpair_name(pair), &saa);
+		if (err != 0) {
+			if (errors != NULL) {
+				fnvlist_add_int32(errors,
+				    nvpair_name(pair), err);
+			}
+			rv = err;
+		}
 	}
 
-	if (temporary) {
-		if (cleanup_fd < 0) {
-			spa_close(spa, FTAG);
-			return (EINVAL);
-		}
-		if ((err = zfs_onexit_fd_hold(cleanup_fd, &minor)) != 0) {
-			spa_close(spa, FTAG);
-			return (err);
+	/*
+	 * If any call to snapshot_one_impl() failed, don't execute the
+	 * sync task.  The error handling code below will clean up the
+	 * snaponearg_t from any successful calls to
+	 * snapshot_one_impl().
+	 */
+	if (rv == 0)
+		err = dsl_sync_task_group_wait(saa.saa_dstg);
+	if (err != 0)
+		rv = err;
+
+	for (dst = list_head(&saa.saa_dstg->dstg_tasks); dst;
+	    dst = list_next(&saa.saa_dstg->dstg_tasks, dst)) {
+		objset_t *os = dst->dst_arg1;
+		snaponearg_t *soa = dst->dst_arg2;
+		if (dst->dst_err != 0) {
+			if (errors != NULL) {
+				fnvlist_add_int32(errors,
+				    soa->soa_longname, dst->dst_err);
+			}
+			rv = dst->dst_err;
 		}
+
+		if (saa.saa_needsuspend)
+			zil_resume(dmu_objset_zil(os));
+		dmu_objset_rele(os, &saa);
+		kmem_free(soa, sizeof (*soa));
 	}
 
-	sn->dstg = dsl_sync_task_group_create(spa_get_dsl(spa));
-	sn->snapname = snapname;
-	sn->htag = tag;
-	sn->props = props;
-	sn->recursive = recursive;
-	sn->needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
-	sn->temporary = temporary;
-	sn->ha = NULL;
-	sn->newds = NULL;
-
-	if (recursive) {
-		err = dmu_objset_find(fsname,
-		    dmu_objset_snapshot_one, sn, DS_FIND_CHILDREN);
-	} else {
-		err = dmu_objset_snapshot_one(fsname, sn);
+	dsl_sync_task_group_destroy(saa.saa_dstg);
+	spa_close(spa, FTAG);
+	return (rv);
+}
+
+int
+dmu_objset_snapshot_one(const char *fsname, const char *snapname)
+{
+	int err;
+	char *longsnap = kmem_asprintf("%s@%s", fsname, snapname);
+	nvlist_t *snaps = fnvlist_alloc();
+
+	fnvlist_add_boolean(snaps, longsnap);
+	err = dmu_objset_snapshot(snaps, NULL, NULL);
+	fnvlist_free(snaps);
+	strfree(longsnap);
+	return (err);
+}
+
+int
+dmu_objset_snapshot_tmp(const char *snapname, const char *tag, int cleanup_fd)
+{
+	dsl_sync_task_t *dst;
+	snapallarg_t saa = { 0 };
+	spa_t *spa;
+	minor_t minor;
+	int err;
+
+	err = spa_open(snapname, &spa, FTAG);
+	if (err)
+		return (err);
+	saa.saa_dstg = dsl_sync_task_group_create(spa_get_dsl(spa));
+	saa.saa_htag = tag;
+	saa.saa_needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
+	saa.saa_temporary = B_TRUE;
+
+	if (cleanup_fd < 0) {
+		spa_close(spa, FTAG);
+		return (EINVAL);
+	}
+	if ((err = zfs_onexit_fd_hold(cleanup_fd, &minor)) != 0) {
+		spa_close(spa, FTAG);
+		return (err);
 	}
 
+	err = snapshot_one_impl(snapname, &saa);
+
 	if (err == 0)
-		err = dsl_sync_task_group_wait(sn->dstg);
+		err = dsl_sync_task_group_wait(saa.saa_dstg);
 
-	for (dst = list_head(&sn->dstg->dstg_tasks); dst;
-	    dst = list_next(&sn->dstg->dstg_tasks, dst)) {
+	for (dst = list_head(&saa.saa_dstg->dstg_tasks); dst;
+	    dst = list_next(&saa.saa_dstg->dstg_tasks, dst)) {
 		objset_t *os = dst->dst_arg1;
-		dsl_dataset_t *ds = os->os_dsl_dataset;
-		if (dst->dst_err) {
-			dsl_dataset_name(ds, sn->failed);
-		} else if (temporary) {
-			dsl_register_onexit_hold_cleanup(sn->newds, tag, minor);
-		}
-		if (sn->needsuspend)
+		dsl_register_onexit_hold_cleanup(saa.saa_newds, tag, minor);
+		if (saa.saa_needsuspend)
 			zil_resume(dmu_objset_zil(os));
-		dmu_objset_rele(os, sn);
+		dmu_objset_rele(os, &saa);
 	}
 
-	if (err)
-		(void) strcpy(fsname, sn->failed);
-	if (temporary)
-		zfs_onexit_fd_rele(cleanup_fd);
-	dsl_sync_task_group_destroy(sn->dstg);
+	zfs_onexit_fd_rele(cleanup_fd);
+	dsl_sync_task_group_destroy(saa.saa_dstg);
 	spa_close(spa, FTAG);
-	kmem_free(sn, sizeof (struct snaparg));
 	return (err);
 }
 
+
 static void
 dmu_objset_sync_dnodes(list_t *list, list_t *newlist, dmu_tx_t *tx)
 {
@@ -1159,7 +1219,7 @@ dmu_objset_sync(objset_t *os, zio_t *pio, dmu_tx_t *tx)
 	dmu_objset_sync_dnodes(&os->os_dirty_dnodes[txgoff], newlist, tx);
 
 	list = &DMU_META_DNODE(os)->dn_dirty_records[txgoff];
-	while ((dr = list_head(list)) != NULL) {
+	while ((dr = list_head(list))) {
 		ASSERT(dr->dr_dbuf->db_level == 0);
 		list_remove(list, dr);
 		if (dr->dr_zio)
@@ -1219,7 +1279,7 @@ dmu_objset_do_userquota_updates(objset_t *os, dmu_tx_t *tx)
 
 	ASSERT(list_head(list) == NULL || dmu_objset_userused_enabled(os));
 
-	while ((dn = list_head(list)) != NULL) {
+	while ((dn = list_head(list))) {
 		int flags;
 		ASSERT(!DMU_OBJECT_IS_SPECIAL(dn->dn_object));
 		ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE ||