From: Dave Chinner <david@fromorbit.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Paul Anderson <pha@umich.edu>,
Sean Thomas Caron <scaron@umich.edu>,
xfs@oss.sgi.com
Subject: Re: [PATCH 2/2 v2] xfs: log all dirty inodes in xfs_fs_sync_fs
Date: Wed, 21 Dec 2011 08:21:06 +1100 [thread overview]
Message-ID: <20111220212106.GY23662@dastard> (raw)
In-Reply-To: <20111220200841.GA2788@infradead.org>
On Tue, Dec 20, 2011 at 03:08:41PM -0500, Christoph Hellwig wrote:
> Since Linux 2.6.36 the writeback code has introduces various measures for
> live lock prevention during sync(). Unfortunately some of these are
> actively harmful for the XFS model, where the inode gets marked dirty for
> metadata from the data I/O handler.
>
> The older_than_this checks that are now more strictly enforced since
>
> writeback: avoid livelocking WB_SYNC_ALL writeback
>
> by only calling into __writeback_inodes_sb and thus only sampling the
> current cut off time once. But on a slow enough devices the previous
> asynchronous sync pass might not have fully completed yet, and thus XFS
> might mark metadata dirty only after that sampling of the cut off time for
> the blocking pass already happened. I have not myself reproduced this
> myself on a real system, but by introducing artificial delay into the
> XFS I/O completion workqueues it can be reproduced easily.
>
> Fix this by iterating over all XFS inodes in ->sync_fs and log all that
> are dirty. This might log inode that only got redirtied after the
> previous pass, but given how cheap delayed logging of inodes is it
> isn't a major concern for performance.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
Looks OK now.
Reviewed-by: Dave Chinner <dchinner@redhat.com>
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2011-12-20 21:21 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20111218154936.GA17626@infradead.org>
2011-12-18 15:49 ` [PATCH 1/1] xfs: log the inode in ->write_inode calls for kupdate Christoph Hellwig
2011-12-20 21:19 ` Dave Chinner
2011-12-23 15:55 ` Mark Tinguely
2011-12-23 17:58 ` Ben Myers
2011-12-28 21:35 ` Hans-Peter Jansen
2011-12-28 21:39 ` Christoph Hellwig
2011-12-18 15:50 ` [PATCH 2/2] xfs: log all dirty inodes in xfs_fs_sync_fs Christoph Hellwig
2011-12-18 20:03 ` Sean Thomas Caron
2011-12-18 20:09 ` Christoph Hellwig
2011-12-18 22:17 ` Dave Chinner
2011-12-18 22:32 ` Christoph Hellwig
2011-12-20 20:08 ` [PATCH 2/2 v2] " Christoph Hellwig
2011-12-20 21:21 ` Dave Chinner [this message]
2011-12-23 15:55 ` Mark Tinguely
2011-12-23 21:47 ` Ben Myers
2011-12-26 12:13 ` Dave Chinner
2011-12-29 15:42 ` Ben Myers
2011-12-29 21:44 ` Dave Chinner
2012-01-03 15:48 ` Mark Tinguely
2011-12-21 17:40 ` sync fixes Christoph Hellwig
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