2 files changed, 34 insertions, 6 deletions

diff --git a/module/zfs/dsl_dataset.c b/module/zfs/dsl_dataset.c
index 5fa04e7ba..bd03b4868 100644
--- a/module/zfs/dsl_dataset.c
+++ b/module/zfs/dsl_dataset.c
@@ -2210,6 +2210,7 @@ dsl_dataset_handoff_check(dsl_dataset_t *ds, void *owner, dmu_tx_t *tx)
 
 typedef struct dsl_dataset_rollback_arg {
 	const char *ddra_fsname;
+	const char *ddra_tosnap;
 	void *ddra_owner;
 	nvlist_t *ddra_result;
 } dsl_dataset_rollback_arg_t;
@@ -2253,6 +2254,18 @@ dsl_dataset_rollback_check(void *arg, dmu_tx_t *tx)
 		return (SET_ERROR(EAGAIN));
 	}
 
+	/*
+	 * If the expected target snapshot is specified, then check that
+	 * the latest snapshot is it.
+	 */
+	if (ddra->ddra_tosnap != NULL) {
+		char namebuf[ZFS_MAX_DATASET_NAME_LEN];
+
+		dsl_dataset_name(ds->ds_prev, namebuf);
+		if (strcmp(namebuf, ddra->ddra_tosnap) != 0)
+			return (SET_ERROR(EXDEV));
+	}
+
 	/* must not have any bookmarks after the most recent snapshot */
 	proprequest = fnvlist_alloc();
 	fnvlist_add_boolean(proprequest, zfs_prop_to_name(ZFS_PROP_CREATETXG));
@@ -2354,11 +2367,13 @@ dsl_dataset_rollback_sync(void *arg, dmu_tx_t *tx)
  * notes above zfs_suspend_fs() for further details.
  */
 int
-dsl_dataset_rollback(const char *fsname, void *owner, nvlist_t *result)
+dsl_dataset_rollback(const char *fsname, const char *tosnap, void *owner,
+    nvlist_t *result)
 {
 	dsl_dataset_rollback_arg_t ddra;
 
 	ddra.ddra_fsname = fsname;
+	ddra.ddra_tosnap = tosnap;
 	ddra.ddra_owner = owner;
 	ddra.ddra_result = result;
 
diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index a2f7f045f..fff1a3c06 100644
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -3653,19 +3653,30 @@ zfs_ioc_destroy(zfs_cmd_t *zc)
 /*
  * fsname is name of dataset to rollback (to most recent snapshot)
  *
- * innvl is not used.
+ * innvl may contain name of expected target snapshot
  *
  * outnvl: "target" -> name of most recent snapshot
  * }
  */
 /* ARGSUSED */
 static int
-zfs_ioc_rollback(const char *fsname, nvlist_t *args, nvlist_t *outnvl)
+zfs_ioc_rollback(const char *fsname, nvlist_t *innvl, nvlist_t *outnvl)
 {
 	zfsvfs_t *zfsvfs;
 	zvol_state_t *zv;
+	char *target = NULL;
 	int error;
 
+	(void) nvlist_lookup_string(innvl, "target", &target);
+	if (target != NULL) {
+		int fslen = strlen(fsname);
+
+		if (strncmp(fsname, target, fslen) != 0)
+			return (SET_ERROR(EINVAL));
+		if (target[fslen] != '@')
+			return (SET_ERROR(EINVAL));
+	}
+
 	if (getzfsvfs(fsname, &zfsvfs) == 0) {
 		dsl_dataset_t *ds;
 
@@ -3674,16 +3685,18 @@ zfs_ioc_rollback(const char *fsname, nvlist_t *args, nvlist_t *outnvl)
 		if (error == 0) {
 			int resume_err;
 
-			error = dsl_dataset_rollback(fsname, zfsvfs, outnvl);
+			error = dsl_dataset_rollback(fsname, target, zfsvfs,
+			    outnvl);
 			resume_err = zfs_resume_fs(zfsvfs, ds);
 			error = error ? error : resume_err;
 		}
 		deactivate_super(zfsvfs->z_sb);
 	} else if ((zv = zvol_suspend(fsname)) != NULL) {
-		error = dsl_dataset_rollback(fsname, zvol_tag(zv), outnvl);
+		error = dsl_dataset_rollback(fsname, target, zvol_tag(zv),
+		    outnvl);
 		zvol_resume(zv);
 	} else {
-		error = dsl_dataset_rollback(fsname, NULL, outnvl);
+		error = dsl_dataset_rollback(fsname, target, NULL, outnvl);
 	}
 	return (error);
 }