From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Subject: Re: [PATCH 5/6] xfs: fix buffer shudown reference count mismatch
Date: Fri, 2 Nov 2012 09:13:26 -0400 [thread overview]
Message-ID: <20121102131326.GG12578@infradead.org> (raw)
In-Reply-To: <20121102024351.GU29378@dastard>
> The fix that I've done here means all buffers going through this
> path will take an extra reference, but that reference is only
> dropped on async buffers. Because all the buffers are markd stale,
> they are removed from the LRU, and so xfs_buftarg_wait() during
> unmount does not find them and hence the remaining reference is
> never removed. Hence the perag reference still remains, and we
> assert fail there.
>
> Solution seems simple - set the XBF_ASYNC flag on all buffers so
> that the last reference is taken away correctly. Testing that now.
I don't like this. ioend processing is very different for synchrous
writes, with the most important difference being that synchronous
writes need to wake the submitter at I/O completion. From all I can
see your v2 patch breaks that beahviour. For 3.7-rc I'd suggest
taking the additional reference conditionally.
For 3.8 I'm going to look into simply acquiring an additional reference
for synchronous writes during I/O submission to kill these special cases
all over the buffer code.
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next prev parent reply other threads:[~2012-11-02 13:11 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-02 0:38 [PATCH 0/6] xfs: fixes for 3.7-rc3 Dave Chinner
2012-11-02 0:38 ` [PATCH 1/6] xfs: silence uninitialised f.file warning Dave Chinner
2012-11-02 13:04 ` Christoph Hellwig
2012-11-02 21:23 ` Mark Tinguely
2012-11-02 0:38 ` [PATCH 2/6] xfs: growfs: don't read garbage for new secondary superblocks Dave Chinner
2012-11-02 0:38 ` [PATCH 3/6] xfs: invalidate allocbt blocks moved to the free list Dave Chinner
2012-10-09 19:11 ` [PATCH] xfs: report projid32bit feature in geometry call Eric Sandeen
2012-10-09 19:28 ` Carlos Maiolino
2012-10-09 19:45 ` Dave Chinner
2012-10-11 0:02 ` Eric Sandeen
2012-10-30 19:43 ` Ben Myers
2012-10-30 19:44 ` Eric Sandeen
2012-11-08 16:12 ` Ben Myers
2012-11-02 21:23 ` [PATCH 3/6] xfs: invalidate allocbt blocks moved to the free list Mark Tinguely
2012-11-02 0:38 ` [PATCH 4/6] xfs: don't vmap inode cluster buffers during free Dave Chinner
2012-11-02 13:05 ` Christoph Hellwig
2012-11-02 21:24 ` Mark Tinguely
2012-11-02 0:38 ` [PATCH 5/6] xfs: fix buffer shudown reference count mismatch Dave Chinner
2012-11-02 2:43 ` Dave Chinner
2012-11-02 3:23 ` [PATCH 5/6 V2] " Dave Chinner
2012-11-02 13:17 ` Mark Tinguely
2012-11-02 13:13 ` Christoph Hellwig [this message]
2012-11-02 17:10 ` [PATCH 5/6] " Mark Tinguely
2012-11-02 23:47 ` Dave Chinner
2012-11-06 12:59 ` Christoph Hellwig
2012-11-06 19:59 ` Dave Chinner
2012-11-02 0:38 ` [PATCH 6/6] xfs: fix reading of wrapped log data Dave Chinner
2012-11-02 13:07 ` Christoph Hellwig
2012-11-02 23:51 ` Dave Chinner
2012-11-02 21:24 ` Mark Tinguely
2012-11-07 20:56 ` [PATCH 0/6] xfs: fixes for 3.7-rc3 Dave Chinner
2012-11-08 16:34 ` Ben Myers
2012-11-08 16:15 ` Ben Myers
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