Illumos #1644, #1645, #1646, #1647, #1708

1644 add ZFS "clones" property
1645 add ZFS "written" and "written@..." properties
1646 "zfs send" should estimate size of stream
1647 "zfs destroy" should determine space reclaimed by
     destroying multiple snapshots
1708 adjust size of zpool history data

References:
  https://www.illumos.org/issues/1644
  https://www.illumos.org/issues/1645
  https://www.illumos.org/issues/1646
  https://www.illumos.org/issues/1647
  https://www.illumos.org/issues/1708

This commit modifies the user to kernel space ioctl ABI.  Extra
care should be taken when updating to ensure both the kernel
modules and utilities are updated.  This change has reordered
all of the new ioctl()s to the end of the list.  This should
help minimize this issue in the future.

Reviewed by: Richard Lowe <[email protected]>
Reviewed by: George Wilson <[email protected]>
Reviewed by: Albert Lee <[email protected]>
Approved by: Garrett D'Amore <[email protected]>

Ported by: Martin Matuska <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #826
Closes #664

1 files changed, 265 insertions, 55 deletions

diff --git a/module/zfs/dsl_dataset.c b/module/zfs/dsl_dataset.c
index 2deec8cf1..25c8ac6b1 100644
--- a/module/zfs/dsl_dataset.c
+++ b/module/zfs/dsl_dataset.c
@@ -907,69 +907,56 @@ dsl_dataset_create_sync(dsl_dir_t *pdd, const char *lastname,
 	return (dsobj);
 }
 
-struct destroyarg {
-	dsl_sync_task_group_t *dstg;
-	char *snapname;
-	char *failed;
-	boolean_t defer;
-};
-
-static int
-dsl_snapshot_destroy_one(const char *name, void *arg)
-{
-	struct destroyarg *da = arg;
-	dsl_dataset_t *ds;
-	int err;
-	char *dsname;
-
-	dsname = kmem_asprintf("%s@%s", name, da->snapname);
-	err = dsl_dataset_own(dsname, B_TRUE, da->dstg, &ds);
-	strfree(dsname);
-	if (err == 0) {
-		struct dsl_ds_destroyarg *dsda;
-
-		dsl_dataset_make_exclusive(ds, da->dstg);
-		dsda = kmem_zalloc(sizeof (struct dsl_ds_destroyarg), KM_SLEEP);
-		dsda->ds = ds;
-		dsda->defer = da->defer;
-		dsl_sync_task_create(da->dstg, dsl_dataset_destroy_check,
-		    dsl_dataset_destroy_sync, dsda, da->dstg, 0);
-	} else if (err == ENOENT) {
-		err = 0;
-	} else {
-		(void) strcpy(da->failed, name);
-	}
-	return (err);
-}
-
 /*
- * Destroy 'snapname' in all descendants of 'fsname'.
+ * The snapshots must all be in the same pool.
  */
-#pragma weak dmu_snapshots_destroy = dsl_snapshots_destroy
 int
-dsl_snapshots_destroy(char *fsname, char *snapname, boolean_t defer)
+dmu_snapshots_destroy_nvl(nvlist_t *snaps, boolean_t defer, char *failed)
 {
 	int err;
-	struct destroyarg da;
 	dsl_sync_task_t *dst;
 	spa_t *spa;
+	nvpair_t *pair;
+	dsl_sync_task_group_t *dstg;
 
-	err = spa_open(fsname, &spa, FTAG);
+	pair = nvlist_next_nvpair(snaps, NULL);
+	if (pair == NULL)
+		return (0);
+
+	err = spa_open(nvpair_name(pair), &spa, FTAG);
 	if (err)
 		return (err);
-	da.dstg = dsl_sync_task_group_create(spa_get_dsl(spa));
-	da.snapname = snapname;
-	da.failed = fsname;
-	da.defer = defer;
+	dstg = dsl_sync_task_group_create(spa_get_dsl(spa));
 
-	err = dmu_objset_find(fsname,
-	    dsl_snapshot_destroy_one, &da, DS_FIND_CHILDREN);
+	for (pair = nvlist_next_nvpair(snaps, NULL); pair != NULL;
+	    pair = nvlist_next_nvpair(snaps, pair)) {
+		dsl_dataset_t *ds;
+		int err;
+
+		err = dsl_dataset_own(nvpair_name(pair), B_TRUE, dstg, &ds);
+		if (err == 0) {
+			struct dsl_ds_destroyarg *dsda;
+
+			dsl_dataset_make_exclusive(ds, dstg);
+			dsda = kmem_zalloc(sizeof (struct dsl_ds_destroyarg),
+			    KM_SLEEP);
+			dsda->ds = ds;
+			dsda->defer = defer;
+			dsl_sync_task_create(dstg, dsl_dataset_destroy_check,
+			    dsl_dataset_destroy_sync, dsda, dstg, 0);
+		} else if (err == ENOENT) {
+			err = 0;
+		} else {
+			(void) strcpy(failed, nvpair_name(pair));
+			break;
+		}
+	}
 
 	if (err == 0)
-		err = dsl_sync_task_group_wait(da.dstg);
+		err = dsl_sync_task_group_wait(dstg);
 
-	for (dst = list_head(&da.dstg->dstg_tasks); dst;
-	    dst = list_next(&da.dstg->dstg_tasks, dst)) {
+	for (dst = list_head(&dstg->dstg_tasks); dst;
+	    dst = list_next(&dstg->dstg_tasks, dst)) {
 		struct dsl_ds_destroyarg *dsda = dst->dst_arg1;
 		dsl_dataset_t *ds = dsda->ds;
 
@@ -977,17 +964,17 @@ dsl_snapshots_destroy(char *fsname, char *snapname, boolean_t defer)
 		 * Return the file system name that triggered the error
 		 */
 		if (dst->dst_err) {
-			dsl_dataset_name(ds, fsname);
-			*strchr(fsname, '@') = '\0';
+			dsl_dataset_name(ds, failed);
 		}
 		ASSERT3P(dsda->rm_origin, ==, NULL);
-		dsl_dataset_disown(ds, da.dstg);
+		dsl_dataset_disown(ds, dstg);
 		kmem_free(dsda, sizeof (struct dsl_ds_destroyarg));
 	}
 
-	dsl_sync_task_group_destroy(da.dstg);
+	dsl_sync_task_group_destroy(dstg);
 	spa_close(spa, FTAG);
 	return (err);
+
 }
 
 static boolean_t
@@ -2151,6 +2138,55 @@ dsl_dataset_sync(dsl_dataset_t *ds, zio_t *zio, dmu_tx_t *tx)
 	dmu_objset_sync(ds->ds_objset, zio, tx);
 }
 
+static void
+get_clones_stat(dsl_dataset_t *ds, nvlist_t *nv)
+{
+	uint64_t count = 0;
+	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
+	zap_cursor_t zc;
+	zap_attribute_t za;
+	nvlist_t *propval;
+	nvlist_t *val;
+
+	rw_enter(&ds->ds_dir->dd_pool->dp_config_rwlock, RW_READER);
+	VERIFY(nvlist_alloc(&propval, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+	VERIFY(nvlist_alloc(&val, NV_UNIQUE_NAME, KM_SLEEP) == 0);
+
+	/*
+	 * There may me missing entries in ds_next_clones_obj
+	 * due to a bug in a previous version of the code.
+	 * Only trust it if it has the right number of entries.
+	 */
+	if (ds->ds_phys->ds_next_clones_obj != 0) {
+		ASSERT3U(0, ==, zap_count(mos, ds->ds_phys->ds_next_clones_obj,
+		    &count));
+	}
+	if (count != ds->ds_phys->ds_num_children - 1) {
+		goto fail;
+	}
+	for (zap_cursor_init(&zc, mos, ds->ds_phys->ds_next_clones_obj);
+	    zap_cursor_retrieve(&zc, &za) == 0;
+	    zap_cursor_advance(&zc)) {
+		dsl_dataset_t *clone;
+		char buf[ZFS_MAXNAMELEN];
+		if (dsl_dataset_hold_obj(ds->ds_dir->dd_pool,
+		    za.za_first_integer, FTAG, &clone) != 0) {
+			goto fail;
+		}
+		dsl_dir_name(clone->ds_dir, buf);
+		VERIFY(nvlist_add_boolean(val, buf) == 0);
+		dsl_dataset_rele(clone, FTAG);
+	}
+	zap_cursor_fini(&zc);
+	VERIFY(nvlist_add_nvlist(propval, ZPROP_VALUE, val) == 0);
+	VERIFY(nvlist_add_nvlist(nv, zfs_prop_to_name(ZFS_PROP_CLONES),
+	    propval) == 0);
+fail:
+	nvlist_free(val);
+	nvlist_free(propval);
+	rw_exit(&ds->ds_dir->dd_pool->dp_config_rwlock);
+}
+
 void
 dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
 {
@@ -2181,6 +2217,27 @@ dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_DEFER_DESTROY,
 	    DS_IS_DEFER_DESTROY(ds) ? 1 : 0);
 
+	if (ds->ds_phys->ds_prev_snap_obj != 0) {
+		uint64_t written, comp, uncomp;
+		dsl_pool_t *dp = ds->ds_dir->dd_pool;
+		dsl_dataset_t *prev;
+		int err;
+
+		rw_enter(&dp->dp_config_rwlock, RW_READER);
+		err = dsl_dataset_hold_obj(dp,
+		    ds->ds_phys->ds_prev_snap_obj, FTAG, &prev);
+		rw_exit(&dp->dp_config_rwlock);
+		if (err == 0) {
+			err = dsl_dataset_space_written(prev, ds, &written,
+			    &comp, &uncomp);
+			dsl_dataset_rele(prev, FTAG);
+			if (err == 0) {
+				dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_WRITTEN,
+				    written);
+			}
+		}
+	}
+
 	ratio = ds->ds_phys->ds_compressed_bytes == 0 ? 100 :
 	    (ds->ds_phys->ds_uncompressed_bytes * 100 /
 	    ds->ds_phys->ds_compressed_bytes);
@@ -2194,6 +2251,8 @@ dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
 		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
 		    ds->ds_phys->ds_unique_bytes);
 		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO, ratio);
+
+		get_clones_stat(ds, nv);
 	}
 }
 
@@ -4022,7 +4081,7 @@ dsl_dataset_get_holds(const char *dsname, nvlist_t **nvp)
 }
 
 /*
- * Note, this fuction is used as the callback for dmu_objset_find().  We
+ * Note, this function is used as the callback for dmu_objset_find().  We
  * always return 0 so that we will continue to find and process
  * inconsistent datasets, even if we encounter an error trying to
  * process one of them.
@@ -4042,7 +4101,157 @@ dsl_destroy_inconsistent(const char *dsname, void *arg)
 	return (0);
 }
 
+
+/*
+ * Return (in *usedp) the amount of space written in new that is not
+ * present in oldsnap.  New may be a snapshot or the head.  Old must be
+ * a snapshot before new, in new's filesystem (or its origin).  If not then
+ * fail and return EINVAL.
+ *
+ * The written space is calculated by considering two components:  First, we
+ * ignore any freed space, and calculate the written as new's used space
+ * minus old's used space.  Next, we add in the amount of space that was freed
+ * between the two snapshots, thus reducing new's used space relative to old's.
+ * Specifically, this is the space that was born before old->ds_creation_txg,
+ * and freed before new (ie. on new's deadlist or a previous deadlist).
+ *
+ * space freed                         [---------------------]
+ * snapshots                       ---O-------O--------O-------O------
+ *                                         oldsnap            new
+ */
+int
+dsl_dataset_space_written(dsl_dataset_t *oldsnap, dsl_dataset_t *new,
+    uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
+{
+	int err = 0;
+	uint64_t snapobj;
+	dsl_pool_t *dp = new->ds_dir->dd_pool;
+
+	*usedp = 0;
+	*usedp += new->ds_phys->ds_used_bytes;
+	*usedp -= oldsnap->ds_phys->ds_used_bytes;
+
+	*compp = 0;
+	*compp += new->ds_phys->ds_compressed_bytes;
+	*compp -= oldsnap->ds_phys->ds_compressed_bytes;
+
+	*uncompp = 0;
+	*uncompp += new->ds_phys->ds_uncompressed_bytes;
+	*uncompp -= oldsnap->ds_phys->ds_uncompressed_bytes;
+
+	rw_enter(&dp->dp_config_rwlock, RW_READER);
+	snapobj = new->ds_object;
+	while (snapobj != oldsnap->ds_object) {
+		dsl_dataset_t *snap;
+		uint64_t used, comp, uncomp;
+
+		err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &snap);
+		if (err != 0)
+			break;
+
+		if (snap->ds_phys->ds_prev_snap_txg ==
+		    oldsnap->ds_phys->ds_creation_txg) {
+			/*
+			 * The blocks in the deadlist can not be born after
+			 * ds_prev_snap_txg, so get the whole deadlist space,
+			 * which is more efficient (especially for old-format
+			 * deadlists).  Unfortunately the deadlist code
+			 * doesn't have enough information to make this
+			 * optimization itself.
+			 */
+			dsl_deadlist_space(&snap->ds_deadlist,
+			    &used, &comp, &uncomp);
+		} else {
+			dsl_deadlist_space_range(&snap->ds_deadlist,
+			    0, oldsnap->ds_phys->ds_creation_txg,
+			    &used, &comp, &uncomp);
+		}
+		*usedp += used;
+		*compp += comp;
+		*uncompp += uncomp;
+
+		/*
+		 * If we get to the beginning of the chain of snapshots
+		 * (ds_prev_snap_obj == 0) before oldsnap, then oldsnap
+		 * was not a snapshot of/before new.
+		 */
+		snapobj = snap->ds_phys->ds_prev_snap_obj;
+		dsl_dataset_rele(snap, FTAG);
+		if (snapobj == 0) {
+			err = EINVAL;
+			break;
+		}
+
+	}
+	rw_exit(&dp->dp_config_rwlock);
+	return (err);
+}
+
+/*
+ * Return (in *usedp) the amount of space that will be reclaimed if firstsnap,
+ * lastsnap, and all snapshots in between are deleted.
+ *
+ * blocks that would be freed            [---------------------------]
+ * snapshots                       ---O-------O--------O-------O--------O
+ *                                        firstsnap        lastsnap
+ *
+ * This is the set of blocks that were born after the snap before firstsnap,
+ * (birth > firstsnap->prev_snap_txg) and died before the snap after the
+ * last snap (ie, is on lastsnap->ds_next->ds_deadlist or an earlier deadlist).
+ * We calculate this by iterating over the relevant deadlists (from the snap
+ * after lastsnap, backward to the snap after firstsnap), summing up the
+ * space on the deadlist that was born after the snap before firstsnap.
+ */
+int
+dsl_dataset_space_wouldfree(dsl_dataset_t *firstsnap,
+    dsl_dataset_t *lastsnap,
+    uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
+{
+	int err = 0;
+	uint64_t snapobj;
+	dsl_pool_t *dp = firstsnap->ds_dir->dd_pool;
+
+	ASSERT(dsl_dataset_is_snapshot(firstsnap));
+	ASSERT(dsl_dataset_is_snapshot(lastsnap));
+
+	/*
+	 * Check that the snapshots are in the same dsl_dir, and firstsnap
+	 * is before lastsnap.
+	 */
+	if (firstsnap->ds_dir != lastsnap->ds_dir ||
+	    firstsnap->ds_phys->ds_creation_txg >
+	    lastsnap->ds_phys->ds_creation_txg)
+		return (EINVAL);
+
+	*usedp = *compp = *uncompp = 0;
+
+	rw_enter(&dp->dp_config_rwlock, RW_READER);
+	snapobj = lastsnap->ds_phys->ds_next_snap_obj;
+	while (snapobj != firstsnap->ds_object) {
+		dsl_dataset_t *ds;
+		uint64_t used, comp, uncomp;
+
+		err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &ds);
+		if (err != 0)
+			break;
+
+		dsl_deadlist_space_range(&ds->ds_deadlist,
+		    firstsnap->ds_phys->ds_prev_snap_txg, UINT64_MAX,
+		    &used, &comp, &uncomp);
+		*usedp += used;
+		*compp += comp;
+		*uncompp += uncomp;
+
+		snapobj = ds->ds_phys->ds_prev_snap_obj;
+		ASSERT3U(snapobj, !=, 0);
+		dsl_dataset_rele(ds, FTAG);
+	}
+	rw_exit(&dp->dp_config_rwlock);
+	return (err);
+}
+
 #if defined(_KERNEL) && defined(HAVE_SPL)
+EXPORT_SYMBOL(dmu_snapshots_destroy_nvl);
 EXPORT_SYMBOL(dsl_dataset_hold);
 EXPORT_SYMBOL(dsl_dataset_hold_obj);
 EXPORT_SYMBOL(dsl_dataset_own);
@@ -4056,7 +4265,6 @@ EXPORT_SYMBOL(dsl_dataset_make_exclusive);
 EXPORT_SYMBOL(dsl_dataset_create_sync);
 EXPORT_SYMBOL(dsl_dataset_create_sync_dd);
 EXPORT_SYMBOL(dsl_dataset_destroy);
-EXPORT_SYMBOL(dsl_snapshots_destroy);
 EXPORT_SYMBOL(dsl_dataset_destroy_check);
 EXPORT_SYMBOL(dsl_dataset_destroy_sync);
 EXPORT_SYMBOL(dsl_dataset_snapshot_check);
@@ -4072,6 +4280,8 @@ EXPORT_SYMBOL(dsl_dataset_get_blkptr);
 EXPORT_SYMBOL(dsl_dataset_set_blkptr);
 EXPORT_SYMBOL(dsl_dataset_get_spa);
 EXPORT_SYMBOL(dsl_dataset_modified_since_lastsnap);
+EXPORT_SYMBOL(dsl_dataset_space_written);
+EXPORT_SYMBOL(dsl_dataset_space_wouldfree);
 EXPORT_SYMBOL(dsl_dataset_sync);
 EXPORT_SYMBOL(dsl_dataset_block_born);
 EXPORT_SYMBOL(dsl_dataset_block_kill);