OpenZFS 8520 - lzc_rollback

8520 lzc_rollback_to should support rolling back to origin
7198 libzfs should gracefully handle EINVAL from lzc_rollback

lzc_rollback_to() should support rolling back to a clone's origin.
The current checks in zfs_ioc_rollback() would not allow that
because the origin snapshot belongs to a different filesystem.
The overly restrictive check was in introduced in 7600, but it
was not a regression as none of the existing tools provided a
way to rollback to the origin.

Authored by: Andriy Gapon <[email protected]>
Reviewed by: Matthew Ahrens <[email protected]>
Approved by: Dan McDonald <[email protected]>
Ported-by: Brian Behlendorf <[email protected]>

OpenZFS-issue: https://www.illumos.org/issues/8520
OpenZFS-issue: https://www.illumos.org/issues/7198
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/78a5a1a25a
Closes #7150

1 files changed, 23 insertions, 9 deletions

diff --git a/lib/libzfs/libzfs_dataset.c b/lib/libzfs/libzfs_dataset.c
index a0e8e7fb6..3d4718025 100644
--- a/lib/libzfs/libzfs_dataset.c
+++ b/lib/libzfs/libzfs_dataset.c
@@ -4211,17 +4211,31 @@ zfs_rollback(zfs_handle_t *zhp, zfs_handle_t *snap, boolean_t force)
 	 * a new snapshot is created before this request is processed.
 	 */
 	err = lzc_rollback_to(zhp->zfs_name, snap->zfs_name);
-	if (err == EXDEV) {
-		zfs_error_aux(zhp->zfs_hdl, dgettext(TEXT_DOMAIN,
-		    "'%s' is not the latest snapshot"), snap->zfs_name);
-		(void) zfs_error_fmt(zhp->zfs_hdl, EZFS_BUSY,
-		    dgettext(TEXT_DOMAIN, "cannot rollback '%s'"),
-		    zhp->zfs_name);
-		return (err);
-	} else if (err != 0) {
-		(void) zfs_standard_error_fmt(zhp->zfs_hdl, errno,
+	if (err != 0) {
+		char errbuf[1024];
+
+		(void) snprintf(errbuf, sizeof (errbuf),
 		    dgettext(TEXT_DOMAIN, "cannot rollback '%s'"),
 		    zhp->zfs_name);
+		switch (err) {
+		case EEXIST:
+			zfs_error_aux(zhp->zfs_hdl, dgettext(TEXT_DOMAIN,
+			    "there is a snapshot or bookmark more recent "
+			    "than '%s'"), snap->zfs_name);
+			(void) zfs_error(zhp->zfs_hdl, EZFS_EXISTS, errbuf);
+			break;
+		case ESRCH:
+			zfs_error_aux(zhp->zfs_hdl, dgettext(TEXT_DOMAIN,
+			    "'%s' is not found among snapshots of '%s'"),
+			    snap->zfs_name, zhp->zfs_name);
+			(void) zfs_error(zhp->zfs_hdl, EZFS_NOENT, errbuf);
+			break;
+		case EINVAL:
+			(void) zfs_error(zhp->zfs_hdl, EZFS_BADTYPE, errbuf);
+			break;
+		default:
+			(void) zfs_standard_error(zhp->zfs_hdl, err, errbuf);
+		}
 		return (err);
 	}