ext4: avoid buffer leak on shutdown in ext4_mark_iloc_dirty()

ext4_mark_iloc_dirty() callers expect that it releases iloc->bh
even if it returns an error.

Fixes: 0db1ff22 ("ext4: add shutdown bit and check for it")
Signed-off-by: NVasily Averin <vvs@virtuozzo.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org # 4.11

fs/ext4/inode.c

@@ -5835,9 +5835,10 @@ int ext4_mark_iloc_dirty(handle_t *handle,
 {
 	int err = 0;
 
-	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb))))
+	if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) {
+		put_bh(iloc->bh);
 		return -EIO;
-
+	}
 	if (IS_I_VERSION(inode))
 		inode_inc_iversion(inode);