From: Alex Elder <aelder@sgi.com>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 2/2] xfs: prevent bogus assert when trying to remove non-existent attribute
Date: Tue, 31 May 2011 17:19:26 -0500 [thread overview]
Message-ID: <1306880366.2865.74.camel@doink> (raw)
In-Reply-To: <1306815659-23346-3-git-send-email-david@fromorbit.com>
On Tue, 2011-05-31 at 14:20 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> If the attribute fork on an inode is in btree format and has
> multiple levels (i.e node format rather than leaf format), then a
> lookup failure will trigger an assert failure in xfs_da_path_shift
> if the flag XFS_DA_OP_OKNOENT is not set. This flag is used to
> indicate to the directory btree code that not finding an entry is
> not a fatal error. In the case of doing a lookup for a directory
> name removal, this is valid as a user cannot insert an arbitrary
> name to remove from the directory btree.
>
> However, in the case of the attribute tree, a user has direct
> control over the attribute name and can ask for any random name to
> be removed without any validation. In this case, fsstress is asking
> for a non-existent user.selinux attribute to be removed, and that is
> causing xfs_da_path_shift() to fall off the bottom of the tree where
> it asserts that a lookup failure is allowed. Because the flag is not
> set, we die a horrible death on a debug enable kernel.
>
> Prevent this assert from firing on attribute removes by adding the
> op_flag XFS_DA_OP_OKNOENT to atribute removal operations.
>
> Discovered when testing on a SELinux enabled system by fsstress in
> test 070 by trying to remove a non-existent user.selinux attribute.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
I have not carefully verified this change, but your
description of the problem was very good so based
on this the change looks right to me.
Signed-off-by: Alex Elder <aelder@sgi.com>
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prev parent reply other threads:[~2011-05-31 22:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-31 4:20 [PATCH 0/2] xfs: couple of fixes for 3.0-rc2 Dave Chinner
2011-05-31 4:20 ` [PATCH 1/2] xfs: clear inode per-lifetime state when recycling it Dave Chinner
2011-05-31 20:09 ` Christoph Hellwig
2011-06-02 0:16 ` Dave Chinner
2011-05-31 22:19 ` Alex Elder
2011-05-31 4:20 ` [PATCH 2/2] xfs: prevent bogus assert when trying to remove non-existent attribute Dave Chinner
2011-05-31 20:10 ` Christoph Hellwig
2011-05-31 22:19 ` Alex Elder [this message]
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