hfsplus: stop workqueue when fill_super() failed

syzbot is reporting ODEBUG messages at hfsplus_fill_super() [1].  This
is because hfsplus_fill_super() forgot to call cancel_delayed_work_sync().

As far as I can see, it is hfsplus_mark_mdb_dirty() from
hfsplus_new_inode() in hfsplus_fill_super() that calls
queue_delayed_work().  Therefore, I assume that hfsplus_new_inode() does
not fail if queue_delayed_work() was called, and the out_put_hidden_dir
label is the appropriate location to call cancel_delayed_work_sync().

[1] https://syzkaller.appspot.com/bug?id=a66f45e96fdbeb76b796bf46eb25ea878c42a6c9

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Tetsuo Handa <[email protected]>
Reported-by: syzbot <[email protected]>
Cc: Al Viro <[email protected]>
Cc: David Howells <[email protected]>
Cc: Ernesto A. Fernandez <[email protected]>
Cc: Vyacheslav Dubeyko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: Tetsuo Handa

fs/hfsplus/super.c

@@ -588,6 +588,7 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
 	return 0;
 
 out_put_hidden_dir:
+	cancel_delayed_work_sync(&sbi->sync_work);
 	iput(sbi->hidden_dir);
 out_put_root:
 	dput(sb->s_root);