ext4: avoid starting transaction on read-only fs in ext4_quota_off()

When the filesystem gets first remounted read-only and then unmounted,
ext4_quota_off() will try to start a transaction (and fail) on read-only
filesystem to cleanup inode flags for legacy quota files. Just bail
before trying to start a transaction instead since that is going to
issue a warning.
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230616165109.21695-6-jack@suse.czSigned-off-by: Theodore Ts'o <tytso@mit.edu>

fs/ext4/super.c

@@ -7072,6 +7072,13 @@ static int ext4_quota_off(struct super_block *sb, int type)
 	err = dquot_quota_off(sb, type);
 	if (err || ext4_has_feature_quota(sb))
 		goto out_put;
+	/*
+	 * When the filesystem was remounted read-only first, we cannot cleanup
+	 * inode flags here. Bad luck but people should be using QUOTA feature
+	 * these days anyway.
+	 */
+	if (sb_rdonly(sb))
+		goto out_put;
 
 	inode_lock(inode);
 	/*