From: Christoph Hellwig <hch@infradead.org>
To: Nikolay Borisov <n.borisov.lkml@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>,
linux-xfs@vger.kernel.org, darrick.wong@oracle.com
Subject: Re: Deadlock between block allocation and block truncation
Date: Wed, 12 Apr 2017 10:57:44 -0700 [thread overview]
Message-ID: <20170412175744.GA20546@infradead.org> (raw)
In-Reply-To: <3e0d4184-9d7a-9ca8-330c-727b183975a6@gmail.com>
On Wed, Apr 12, 2017 at 08:44:32PM +0300, Nikolay Borisov wrote:
> "
> djwong: either agf1 is clean and it needs to release that before going
> for agf0, or agf1 is dirty and thus it cannot go for agf0
> "
Yes. Older kernels had some bugs in this area due to busy extent
tracking, where xfs_alloc_ag_vextent would fail despite
xfs_alloc_fix_freelist picking an AG and possibly dirtying the AGF.
My busy extent tracking changes for the asynchronous discard code in
4.11-rc should have fixed that.
But even with that in place I think that locking two AGFs in any
order in the truncate path is wrong.
next prev parent reply other threads:[~2017-04-12 17:57 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-12 15:51 Deadlock between block allocation and block truncation Nikolay Borisov
2017-04-12 16:10 ` Christoph Hellwig
2017-04-12 16:12 ` Nikolay Borisov
2017-04-12 16:20 ` Christoph Hellwig
2017-04-12 17:44 ` Nikolay Borisov
2017-04-12 17:57 ` Christoph Hellwig [this message]
2017-04-13 13:52 ` Nikolay Borisov
2017-04-14 7:42 ` Christoph Hellwig
2017-04-25 7:36 ` Christoph Hellwig
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