ext4: ignore journalled data options on remount if fs has no journal

This avoids a confusing failure in the init scripts when the
/etc/fstab has data=writeback or data=journal but the file system does
not have a journal.  So check for this case explicitly, and warn the
user that we are ignoring the (pointless, since they have no journal)
data=* mount option.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9953d80145ad..0435013dbd46 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1683,7 +1683,9 @@ static int parse_options(char *options, struct super_block *sb,
                         data_opt = EXT4_MOUNT_WRITEBACK_DATA;
                 datacheck:
                         if (is_remount) {
-                                if (test_opt(sb, DATA_FLAGS) != data_opt) {
+                                if (!sbi->s_journal)
+                                        ext4_msg(sb, KERN_WARNING, "Remounting file system with no journal so ignoring journalled data option");
+                                else if (test_opt(sb, DATA_FLAGS) != data_opt) {
                                         ext4_msg(sb, KERN_ERR,
                                                 "Cannot change data mode on remount");
                                         return 0;