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From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@infradead.org>, xfs@oss.sgi.com
Subject: Re: [PATCH 5/6] xfs: fix buffer shudown reference count mismatch
Date: Tue, 6 Nov 2012 07:59:49 -0500	[thread overview]
Message-ID: <20121106125949.GA32329@infradead.org> (raw)
In-Reply-To: <20121102234741.GB29378@dastard>

On Sat, Nov 03, 2012 at 10:47:41AM +1100, Dave Chinner wrote:
> I think that's irrelevant here - there will *never* be an IO waiter
> at this point in time.  This processing is in log buffer IO
> completion context, so the buffers are still pinned in memory. Hence
> anyone trying to do IO on it will be waiting in xfs_buf_wait_unpin()
> and never get to xfs_buf_iowait(). And because xfs_buf_wait_unpin()
> is called with the buffer lock held, we'll never do the failure
> handling in xfs_buf_item_unpin until the buffer IO is completed and
> it is unlocked.

How do we manage to submit it synchronously then?  The inode and dquot
reclaim xfs_bwrite calls already wait for an unpin first, so I don't
think these are the problem.  The only other call on a live fs seems
to xfs_qm_shake -> xfs_buf_delwri_submit, but that one does wait
for the complete() call on b_iowait.  I suspect we are hitting that
and due to it skipping the wait if b_ioerror is set and waiting on
multiple buffers that complete together might hide the issue.

__xfs_buf_delwri_submit for the wait == true case also seems to be
the only place that actually skips the ispinned check.

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  reply	other threads:[~2012-11-06 12:57 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     ` [PATCH 5/6] " Christoph Hellwig
2012-11-02 17:10       ` Mark Tinguely
2012-11-02 23:47       ` Dave Chinner
2012-11-06 12:59         ` Christoph Hellwig [this message]
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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