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From: David Howells <dhowells@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: dhowells@redhat.com, torvalds@linux-foundation.org,
	linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org,
	anton@samba.org, stable@kernel.org
Subject: Re: [PATCH] AFS: Stop readlink() on AFS crashing because file not passed to afs_readpage()
Date: Fri, 28 Aug 2009 15:01:18 +0100	[thread overview]
Message-ID: <1302.1251468078@redhat.com> (raw)
In-Reply-To: <20090827145359.87367779.akpm@linux-foundation.org>

Andrew Morton <akpm@linux-foundation.org> wrote:

> That seems like a rather large bug.

Indeed.

I've not seen this happen because when a symlink inode is filled in,
afs_mntpt_check_symlink() is called to see whether it's actually a mountpoint,
and *that* calls read_mapping_page() correctly to read the contents of the
symlink.

The contents of the symlink then hang around in the pagecache, preventing
further calls to afs_readpage() by page_getlink().

However, if you wait long enough, as presumably Anton has, the contents of the
symlink get ejected from the pagecache, but the inode is retained, and thus
the next readlink will oops.

> To which kernel version(s) should we apply this?

kAFS isn't that widely used yet, so only the latest, I think.

David

  reply	other threads:[~2009-08-28 14:04 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-08-27 12:22 [PATCH] AFS: Stop readlink() on AFS crashing because file not passed to afs_readpage() David Howells
2009-08-27 21:53 ` Andrew Morton
2009-08-28 14:01   ` David Howells [this message]
  -- strict thread matches above, loose matches on Subject: below --
2009-08-27 12:09 David Howells
2009-08-27 12:32 ` David Howells

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