ext4: reject the 'commit' option on ext2 filesystems

The 'commit' option is only applicable for ext3 and ext4 filesystems,
and has never been accepted by the ext2 filesystem driver, so the ext4
driver shouldn't allow it on ext2 filesystems.

This fixes a failure in xfstest ext4/053.

Fixes: 8dc0aa8 ("ext4: check incompatible mount options while mounting ext2/3")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Ritesh Harjani <ritesh.list@gmail.com>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Link: https://lore.kernel.org/r/20220510183232.172615-1-ebiggers@kernel.org

Author: ebiggers

fs/ext4/super.c

@@ -1915,6 +1915,7 @@ static const struct mount_opts {
 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
 	{Opt_warn_on_error, EXT4_MOUNT_WARN_ON_ERROR, MOPT_SET},
 	{Opt_nowarn_on_error, EXT4_MOUNT_WARN_ON_ERROR, MOPT_CLEAR},
+	{Opt_commit, 0, MOPT_NO_EXT2},
 	{Opt_nojournal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,
 	 MOPT_EXT4_ONLY | MOPT_CLEAR},
 	{Opt_journal_checksum, EXT4_MOUNT_JOURNAL_CHECKSUM,