Extend r226676 to allow rename without unmount even for file systems with

non-legacy mountpoints. It is better to be able to rename such file systems and
let them be mounted in old places until next reboot than using live CD, etc. to
rename with remount.

This is implemented by adding -u option to 'zfs rename'. If file system's
mountpoint property is set to 'legacy' or 'none', there is no need to specify -u.

Update zfs(8) manual page to reflect this addition.

MFC after:	2 weeks

1 files changed, 22 insertions, 13 deletions

diff --git a/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_dataset.c b/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_dataset.c
index bdd48b1..976d7e9 100644
--- a/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_dataset.c
+++ b/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_dataset.c
@@ -3480,7 +3480,7 @@ zfs_iter_dependents(zfs_handle_t *zhp, boolean_t allowrecursion,
  * Renames the given dataset.
  */
 int
-zfs_rename(zfs_handle_t *zhp, const char *target, boolean_t recursive)
+zfs_rename(zfs_handle_t *zhp, const char *target, renameflags_t flags)
 {
 	int ret;
 	zfs_cmd_t zc = { 0 };
@@ -3536,7 +3536,7 @@ zfs_rename(zfs_handle_t *zhp, const char *target, boolean_t recursive)
 		if (!zfs_validate_name(hdl, target, zhp->zfs_type, B_TRUE))
 			return (zfs_error(hdl, EZFS_INVALIDNAME, errbuf));
 	} else {
-		if (recursive) {
+		if (flags.recurse) {
 			zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
 			    "recursive rename must be a snapshot"));
 			return (zfs_error(hdl, EZFS_BADTYPE, errbuf));
@@ -3577,7 +3577,20 @@ zfs_rename(zfs_handle_t *zhp, const char *target, boolean_t recursive)
 		return (zfs_error(hdl, EZFS_ZONED, errbuf));
 	}
 
-	if (recursive) {
+	/*
+	 * Avoid unmounting file systems with mountpoint property set to
+	 * 'legacy' or 'none' even if -u option is not given.
+	 */
+	if (zhp->zfs_type == ZFS_TYPE_FILESYSTEM &&
+	    !flags.recurse && !flags.nounmount &&
+	    zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT, property,
+	    sizeof (property), NULL, NULL, 0, B_FALSE) == 0 &&
+	    (strcmp(property, "legacy") == 0 ||
+	     strcmp(property, "none") == 0)) {
+		flags.nounmount = B_TRUE;
+	}
+
+	if (flags.recurse) {
 
 		parentname = zfs_strdup(zhp->zfs_hdl, zhp->zfs_name);
 		if (parentname == NULL) {
@@ -3594,7 +3607,7 @@ zfs_rename(zfs_handle_t *zhp, const char *target, boolean_t recursive)
 
 	} else {
 		if ((cl = changelist_gather(zhp, ZFS_PROP_NAME,
-		    CL_GATHER_KEEP_LEGACY, 0)) == NULL) {
+		    flags.nounmount ? CL_GATHER_DONT_UNMOUNT : 0, 0)) == NULL) {
 			return (-1);
 		}
 
@@ -3618,13 +3631,9 @@ zfs_rename(zfs_handle_t *zhp, const char *target, boolean_t recursive)
 	(void) strlcpy(zc.zc_name, zhp->zfs_name, sizeof (zc.zc_name));
 	(void) strlcpy(zc.zc_value, target, sizeof (zc.zc_value));
 
-	zc.zc_cookie = recursive ? 1 : 0;
-	if (zfs_prop_get(zhp, ZFS_PROP_MOUNTPOINT, property, sizeof (property),
-	    NULL, NULL, 0, B_FALSE) == 0 &&
-	    (strcmp(property, "legacy") == 0 ||
-	     strcmp(property, "none") == 0)) {
+	zc.zc_cookie = flags.recurse ? 1 : 0;
+	if (flags.nounmount)
 		zc.zc_cookie |= 2;
-	}
 
 	if ((ret = zfs_ioctl(zhp->zfs_hdl, ZFS_IOC_RENAME, &zc)) != 0) {
 		/*
@@ -3634,7 +3643,7 @@ zfs_rename(zfs_handle_t *zhp, const char *target, boolean_t recursive)
 		(void) snprintf(errbuf, sizeof (errbuf), dgettext(TEXT_DOMAIN,
 		    "cannot rename '%s'"), zc.zc_name);
 
-		if (recursive && errno == EEXIST) {
+		if (flags.recurse && errno == EEXIST) {
 			zfs_error_aux(hdl, dgettext(TEXT_DOMAIN,
 			    "a child dataset already has a snapshot "
 			    "with the new name"));
@@ -3647,10 +3656,10 @@ zfs_rename(zfs_handle_t *zhp, const char *target, boolean_t recursive)
 		 * On failure, we still want to remount any filesystems that
 		 * were previously mounted, so we don't alter the system state.
 		 */
-		if (!recursive)
+		if (!flags.recurse)
 			(void) changelist_postfix(cl);
 	} else {
-		if (!recursive) {
+		if (!flags.recurse) {
 			changelist_rename(cl, zfs_get_name(zhp), target);
 			ret = changelist_postfix(cl);
 		}