From: Eric Sandeen <sandeen@redhat.com>
To: Jan Kara <jack@suse.cz>
Cc: tytso@mit.edu, Tao Ma <tm@tao.ma>, linux-ext4@vger.kernel.org
Subject: Re: [PATCH] jbd2: Fix forever sleeping process in do_get_write_access()
Date: Thu, 05 May 2011 09:28:30 -0500 [thread overview]
Message-ID: <4DC2B40E.8080709@redhat.com> (raw)
In-Reply-To: <20110505141114.GG5323@quack.suse.cz>
On 5/5/11 9:11 AM, Jan Kara wrote:
> On Thu 05-05-11 08:49:14, Eric Sandeen wrote:
>> On 5/5/11 7:10 AM, Jan Kara wrote:
>>> In do_get_write_access() we wait on BH_Unshadow bit for buffer to get
>>> from shadow state. The waking code in journal_commit_transaction() has
>>> a bug because it does not issue a memory barrier after the buffer is moved
>>> from the shadow state and before wake_up_bit() is called. Thus a waitqueue
>>> check can happen before the buffer is actually moved from the shadow state
>>> and waiting process may never be woken. Fix the problem by issuing proper
>>> barrier.
>>
>> needed for jbd/commit.c as well, I guess?
> Yes, I was already queued in my tree. I just sent it to the list as well.
sorry, sometimes "we" forget :)
Thanks!
-Eric
next prev parent reply other threads:[~2011-05-05 14:28 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-05 12:10 [PATCH] jbd2: Fix forever sleeping process in do_get_write_access() Jan Kara
2011-05-05 13:49 ` Eric Sandeen
2011-05-05 14:11 ` Jan Kara
2011-05-05 14:28 ` Eric Sandeen [this message]
2011-05-08 23:14 ` Ted Ts'o
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