From: Dave Chinner <david@fromorbit.com>
To: tinguely@sgi.com
Cc: xfs@oss.sgi.com
Subject: Re: [RFC] xfs: wait for the write of the superblock on unmount
Date: Thu, 19 Jul 2012 11:58:09 +1000 [thread overview]
Message-ID: <20120719015809.GC23387@dastard> (raw)
In-Reply-To: <20120718220003.396849822@tinguelysgi.com>
On Wed, Jul 18, 2012 at 12:33:58PM -0500, tinguely@sgi.com wrote:
> Sorry, I have been distracted away from this regression. This was previously
> titled "xfs: synchronously write the superblock on unmount".
>
> xfs_wait_buftarg() does not wait for the completion of the write of the
> uncached superblock. This write can race with the shutdown of the log and
> causes a panic if the write does not win the race.
>
> The log write of the superblock is important for possible recovery, but a
> second syncronous write of the same superblock seems redundant. Would just
> waiting for the iodone() of the log write before tearing down the log be
> enough?
Yes. i.e. something like:
/*
* The superblock buffer is uncached, so xfs_wait_buftarg()
* will not wait for it. Hence we need to explicitly wait
* for IO completion on the superblock to occur here.
*/
error = xfs_buf_iowait(mp->m_sb_bp);
if (error)
AAAAIEEEE!
This fix is also needed in xfs_quiesce_attr() for the freeze and
ro,remount cases as well.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2012-07-19 1:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20120717215957.855744999@tinguelysgi.com>
2012-07-18 17:33 ` [RFC] xfs: wait for the write of the superblock on unmount tinguely
2012-07-19 1:58 ` Dave Chinner [this message]
2012-07-20 13:21 ` Mark Tinguely
2012-07-20 21:24 ` Mark Tinguely
2012-07-24 13:57 ` Christoph Hellwig
2012-07-24 14:03 ` Mark Tinguely
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