MFV r253782:

To quote Illumos issue #3888:

When 'zfs recv -F' is used with an incremental recv it rolls
back any changes made since the last snapshot in case new
changes were made to the file system while the recv is in
progress (without -F the recv would fail when it does it's
final check to commit the recv-ed data as the recv-ed data
conflicts with the newly written data).

However, if there is a snapshot taken after the recv began
rolling back to the 'latest' snapshot will not help and the
recv will still fail. 'zfs recv -F' should be extended to
destroy any snapshots created since the source snapshot when
finishing the recv (effectively rolling back through all
snapshots, instead of just to the latest snapshot).

Illumos ZFS issues:
  3888 zfs recv -F should destroy any snapshots created since the
       incremental source

MFC after:	2 weeks

1 files changed, 12 insertions, 11 deletions

diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
index 774f354..1faebc1 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dataset.c
@@ -1593,16 +1593,16 @@ dsl_dataset_space(dsl_dataset_t *ds,
 }
 
 boolean_t
-dsl_dataset_modified_since_lastsnap(dsl_dataset_t *ds)
+dsl_dataset_modified_since_snap(dsl_dataset_t *ds, dsl_dataset_t *snap)
 {
 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
 
 	ASSERT(dsl_pool_config_held(dp));
-	if (ds->ds_prev == NULL)
+	if (snap == NULL)
 		return (B_FALSE);
 	if (ds->ds_phys->ds_bp.blk_birth >
-	    ds->ds_prev->ds_phys->ds_creation_txg) {
-		objset_t *os, *os_prev;
+	    snap->ds_phys->ds_creation_txg) {
+		objset_t *os, *os_snap;
 		/*
 		 * It may be that only the ZIL differs, because it was
 		 * reset in the head.  Don't count that as being
@@ -1610,10 +1610,10 @@ dsl_dataset_modified_since_lastsnap(dsl_dataset_t *ds)
 		 */
 		if (dmu_objset_from_ds(ds, &os) != 0)
 			return (B_TRUE);
-		if (dmu_objset_from_ds(ds->ds_prev, &os_prev) != 0)
+		if (dmu_objset_from_ds(snap, &os_snap) != 0)
 			return (B_TRUE);
 		return (bcmp(&os->os_phys->os_meta_dnode,
-		    &os_prev->os_phys->os_meta_dnode,
+		    &os_snap->os_phys->os_meta_dnode,
 		    sizeof (os->os_phys->os_meta_dnode)) != 0);
 	}
 	return (B_FALSE);
@@ -2436,15 +2436,14 @@ dsl_dataset_clone_swap_check_impl(dsl_dataset_t *clone,
 	    dsl_dataset_is_snapshot(origin_head))
 		return (SET_ERROR(EINVAL));
 
-	/* the branch point should be just before them */
-	if (clone->ds_prev != origin_head->ds_prev)
+	/* if we are not forcing, the branch point should be just before them */
+	if (!force && clone->ds_prev != origin_head->ds_prev)
 		return (SET_ERROR(EINVAL));
 
 	/* clone should be the clone (unless they are unrelated) */
 	if (clone->ds_prev != NULL &&
 	    clone->ds_prev != clone->ds_dir->dd_pool->dp_origin_snap &&
-	    origin_head->ds_object !=
-	    clone->ds_prev->ds_phys->ds_next_snap_obj)
+	    origin_head->ds_dir != clone->ds_prev->ds_dir)
 		return (SET_ERROR(EINVAL));
 
 	/* the clone should be a child of the origin */
@@ -2452,7 +2451,8 @@ dsl_dataset_clone_swap_check_impl(dsl_dataset_t *clone,
 		return (SET_ERROR(EINVAL));
 
 	/* origin_head shouldn't be modified unless 'force' */
-	if (!force && dsl_dataset_modified_since_lastsnap(origin_head))
+	if (!force &&
+	    dsl_dataset_modified_since_snap(origin_head, origin_head->ds_prev))
 		return (SET_ERROR(ETXTBSY));
 
 	/* origin_head should have no long holds (e.g. is not mounted) */
@@ -2489,6 +2489,7 @@ dsl_dataset_clone_swap_sync_impl(dsl_dataset_t *clone,
 	ASSERT(clone->ds_reserved == 0);
 	ASSERT(origin_head->ds_quota == 0 ||
 	    clone->ds_phys->ds_unique_bytes <= origin_head->ds_quota);
+	ASSERT3P(clone->ds_prev, ==, origin_head->ds_prev);
 
 	dmu_buf_will_dirty(clone->ds_dbuf, tx);
 	dmu_buf_will_dirty(origin_head->ds_dbuf, tx);