linux-kernel - Re: ocfs2: xattr problems with 5.4.0-rc7

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Date:   Wed, 13 Nov 2019 09:28:39 +0800
From:   Joseph Qi <joseph.qi@...ux.alibaba.com>
To:     Thomas Voegtle <tv@...96.de>, Jia-Ju Bai <baijiaju1990@...il.com>,
        Mark Fasheh <mark@...heh.com>, Joel Becker <jlbec@...lplan.org>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: ocfs2: xattr problems with 5.4.0-rc7

Hi Thomas,
Thanks for reporting this issue.
I have some doubts on it, please see my comments below.

On 19/11/12 22:45, Thomas Voegtle wrote:
> 
> Hello,
> 
> with 5.4.0-rc7 and 4.9.200 we see the following errors with mkdir or touch on a ocfs2 mountpoint:
> 
> root@s2:/shared/ClusterShareDisk# mkdir dir
> mkdir: cannot create directory ‘dir’: Invalid argument
> 
> which produces this output:
> 
> root@s2:/shared/ClusterShareDisk# dmesg
> [ 6918.815770] (mkdir,19461,0):ocfs2_xa_set:2242 ERROR: status = -22
> [ 6918.815772] (mkdir,19461,0):ocfs2_mknod:408 ERROR: status = -22
> [ 6918.816215] (mkdir,19461,0):ocfs2_mknod:486 ERROR: status = -22
> [ 6918.816216] (mkdir,19461,0):ocfs2_mkdir:652 ERROR: status = -22
> 
ocfs2_xa_set
  ocfs2_xa_prepare_entry

Since ocfs2_xa_set() returns -EINVAL, it means loc->xl_entry is NULL.

	if (!loc->xl_entry) {
		rc = -EINVAL;
		goto out;
	}

After reverting
commit 56e94ea132bb "fs: ocfs2: fix possible null-pointer dereferences in ocfs2_xa_prepare_entry()",
it will call ocfs2_xa_add_entry(),

	if (loc->xl_entry) {
		...
	} else
		ocfs2_xa_add_entry(loc, name_hash);

Theoretically it will cause NULL pointer dereference when access attributes of loc->xl_entry.
So could you please check if the issue is caused by NULL loc->xl_entry?

Thanks,
Joseph

> We got some ACLs:
> $ getfacl /shared/ClusterShareDisk/
> getfacl: Removing leading '/' from absolute path names
> # file: shared/ClusterShareDisk/
> # owner: root
> # group: root
> user::rwx
> user:admin:rwx
> group::rwx
> mask::rwx
> other::---
> default:user::rwx
> default:user:admin:rwx
> default:group::rwx
> default:mask::rwx
> default:other::---
> 
> And of course it is mounted with user_xattr and acl option.
> 
> Reverting
> commit 56e94ea132bb5c2c1d0b60a6aeb34dcb7d71a53d
> Author: Jia-Ju Bai <baijiaju1990@...il.com>
> Date:   Sun Oct 6 17:57:50 2019 -0700
> 
>     fs: ocfs2: fix possible null-pointer dereferences in
> ocfs2_xa_prepare_entry()
> 
> fixes the problem.
> 
> Greetings,
> 
> 
>     Thomas