ext4: disallow changing journal_csum option during remount
ext4 does not permit changing the metadata or journal checksum feature
flag while mounted. Until we decide to support that, don't allow a
remount to change the journal_csum flag (right now we silently fail to
change anything).
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 5c11e21..96059e0 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4845,6 +4845,14 @@
goto restore_opts;
}
+ if ((old_opts.s_mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) ^
+ test_opt(sb, JOURNAL_CHECKSUM)) {
+ ext4_msg(sb, KERN_ERR, "changing journal_checksum "
+ "during remount not supported");
+ err = -EINVAL;
+ goto restore_opts;
+ }
+
if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
if (test_opt2(sb, EXPLICIT_DELALLOC)) {
ext4_msg(sb, KERN_ERR, "can't mount with "