From: Jan Schmidt <list.btrfs@jan-o-sch.net>
To: Josef Bacik <jbacik@fusionio.com>,
linux-btrfs <linux-btrfs@vger.kernel.org>
Cc: "Chris L. Mason" <clmason@fusionio.com>
Subject: Re: Deadlock in ctree.c?
Date: Fri, 22 Jun 2012 16:26:56 +0200 [thread overview]
Message-ID: <4FE480B0.50201@jan-o-sch.net> (raw)
In-Reply-To: <4FE47FD6.9010205@fusionio.com>
On Fri, June 22, 2012 at 16:23 (+0200), Josef Bacik wrote:
> On 06/22/2012 09:38 AM, Jan Schmidt wrote:
>> On Fri, June 22, 2012 at 15:30 (+0200), Josef Bacik wrote:
>>> l2 shouldn't be locked anymore, if we're in push_leaf_left it's because we
>>> cow'ed l2 and are holding a lock on it, so really it has a lock on l2' and the
>>> btrfs_next_leaf is trying to get a lock on l2 which it should be free to do.
>>
>> Each tree block is cowed only once per transaction, right? Lets assume l2 was
>> cowed before any of the above threads started, we should end up with a lock on
>> l2 even in push_leaf_left, because should_cow_block returns 0.
>>
>
> Except you'd never get to l2 in the case that it had already been cow'ed. Thanks,
Thank you :-) That's the missing bit.
-Jan
prev parent reply other threads:[~2012-06-22 14:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-22 11:00 Deadlock in ctree.c? Jan Schmidt
2012-06-22 13:30 ` Josef Bacik
2012-06-22 13:38 ` Jan Schmidt
2012-06-22 14:23 ` Josef Bacik
2012-06-22 14:26 ` Jan Schmidt [this message]
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