Illumos #3996

3996 want a libzfs_core API to rollback to latest snapshot
Reviewed by: Christopher Siden <[email protected]>
Reviewed by: Adam Leventhal <[email protected]>
Reviewed by: George Wilson <[email protected]>
Reviewed by: Andy Stormont <[email protected]>
Approved by: Richard Lowe <[email protected]>

References:
  https://www.illumos.org/issues/3996
  illumos/illumos-gate@a7027df17fad220a20367b9d1eb251bc6300d203

Ported-by: Richard Yao <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Issue #1775

2 files changed, 27 insertions, 11 deletions

diff --git a/lib/libzfs/libzfs_dataset.c b/lib/libzfs/libzfs_dataset.c
index 3b5fc4549..8c4b924e2 100644
--- a/lib/libzfs/libzfs_dataset.c
+++ b/lib/libzfs/libzfs_dataset.c
@@ -3732,7 +3732,6 @@ zfs_rollback(zfs_handle_t *zhp, zfs_handle_t *snap, boolean_t force)
 {
 	rollback_data_t cb = { 0 };
 	int err;
-	zfs_cmd_t zc = {"\0"};
 	boolean_t restore_resv = 0;
 	uint64_t old_volsize = 0, new_volsize;
 	zfs_prop_t resv_prop = { 0 };
@@ -3766,22 +3765,15 @@ zfs_rollback(zfs_handle_t *zhp, zfs_handle_t *snap, boolean_t force)
 		    (old_volsize == zfs_prop_get_int(zhp, resv_prop));
 	}
 
-	(void) strlcpy(zc.zc_name, zhp->zfs_name, sizeof (zc.zc_name));
-
-	if (ZFS_IS_VOLUME(zhp))
-		zc.zc_objset_type = DMU_OST_ZVOL;
-	else
-		zc.zc_objset_type = DMU_OST_ZFS;
-
 	/*
 	 * We rely on zfs_iter_children() to verify that there are no
 	 * newer snapshots for the given dataset.  Therefore, we can
 	 * simply pass the name on to the ioctl() call.  There is still
 	 * an unlikely race condition where the user has taken a
 	 * snapshot since we verified that this was the most recent.
-	 *
 	 */
-	if ((err = zfs_ioctl(zhp->zfs_hdl, ZFS_IOC_ROLLBACK, &zc)) != 0) {
+	err = lzc_rollback(zhp->zfs_name, NULL, 0);
+	if (err != 0) {
 		(void) zfs_standard_error_fmt(zhp->zfs_hdl, errno,
 		    dgettext(TEXT_DOMAIN, "cannot rollback '%s'"),
 		    zhp->zfs_name);
diff --git a/lib/libzfs_core/libzfs_core.c b/lib/libzfs_core/libzfs_core.c
index 53c813d4a..3befa4d84 100644
--- a/lib/libzfs_core/libzfs_core.c
+++ b/lib/libzfs_core/libzfs_core.c
@@ -20,7 +20,7 @@
  */
 
 /*
- * Copyright (c) 2012 by Delphix. All rights reserved.
+ * Copyright (c) 2013 by Delphix. All rights reserved.
  * Copyright (c) 2013 Steven Hartland. All rights reserved.
  */
 
@@ -581,3 +581,27 @@ out:
 	free((void*)(uintptr_t)zc.zc_nvlist_dst);
 	return (error);
 }
+
+/*
+ * Roll back this filesystem or volume to its most recent snapshot.
+ * If snapnamebuf is not NULL, it will be filled in with the name
+ * of the most recent snapshot.
+ *
+ * Return 0 on success or an errno on failure.
+ */
+int
+lzc_rollback(const char *fsname, char *snapnamebuf, int snapnamelen)
+{
+	nvlist_t *args;
+	nvlist_t *result;
+	int err;
+
+	args = fnvlist_alloc();
+	err = lzc_ioctl(ZFS_IOC_ROLLBACK, fsname, args, &result);
+	nvlist_free(args);
+	if (err == 0 && snapnamebuf != NULL) {
+		const char *snapname = fnvlist_lookup_string(result, "target");
+		(void) strlcpy(snapnamebuf, snapname, snapnamelen);
+	}
+	return (err);
+}