Change behavior introduced in r237119 to vendor solution

References:
https://www.illumos.org/issues/2883

PR:		167905
Obtained from:	illumos (issue #2883)
MFC after:	2 weeks

1 files changed, 10 insertions, 7 deletions

diff --git a/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_dataset.c b/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_dataset.c
index 1d81f91..895475a 100644
--- a/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_dataset.c
+++ b/cddl/contrib/opensolaris/lib/libzfs/common/libzfs_dataset.c
@@ -1484,14 +1484,17 @@ zfs_prop_set(zfs_handle_t *zhp, const char *propname, const char *propval)
 	}
 
 	/*
-	 * If the dataset's canmount property is being set to noauto,
-	 * or being set to on and the dataset is already mounted,
-	 * then we want to prevent unmounting & remounting it.
+	 * We don't want to unmount & remount the dataset when changing
+	 * its canmount property to 'on' or 'noauto'.  We only use
+	 * the changelist logic to unmount when setting canmount=off.
 	 */
-	do_prefix = !((prop == ZFS_PROP_CANMOUNT) &&
-	    (zprop_string_to_index(prop, propval, &idx,
-	    ZFS_TYPE_DATASET) == 0) && (idx == ZFS_CANMOUNT_NOAUTO ||
-	    (idx == ZFS_CANMOUNT_ON && zfs_is_mounted(zhp, NULL))));
+	if (prop == ZFS_PROP_CANMOUNT) {
+		uint64_t idx;
+		int err = zprop_string_to_index(prop, propval, &idx,
+		    ZFS_TYPE_DATASET);
+		if (err == 0 && idx != ZFS_CANMOUNT_OFF)
+			do_prefix = B_FALSE;
+	}
 
 	if (do_prefix && (ret = changelist_prefix(cl)) != 0)
 		goto error;