reiserfs: destroy allocated commit workqueue

When resirefs is trying to mount a partition, it creates a commit
workqueue (sbi->commit_wq). But when mount fails later, the workqueue
is not freed.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: auxsvr@gmail.com
Reported-by: Benoît Monin <benoit.monin@gmx.fr>
Cc: Jan Kara <jack@suse.cz>
Cc: stable@vger.kernel.org # >= 3.16
Cc: reiserfs-devel@vger.kernel.org
Fixes: 797d901
Signed-off-by: Jan Kara <jack@suse.cz>

fs/reiserfs/super.c

@@ -2172,6 +2172,9 @@ static int reiserfs_fill_super(struct super_block *s, void *data, int silent)
 		reiserfs_write_unlock(s);
 	}
 
+	if (sbi->commit_wq)
+		destroy_workqueue(sbi->commit_wq);
+
 	cancel_delayed_work_sync(&REISERFS_SB(s)->old_work);
 
 	reiserfs_free_bitmap_cache(s);