linux-kernel - Re: [PATCH v1 0/9] fs: fix up AIO+DIO+O

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Message-ID: <20121120185700.GD8740@blackbox.djwong.org>
Date:	Tue, 20 Nov 2012 10:57:00 -0800
From:	"Darrick J. Wong" <darrick.wong@...cle.com>
To:	Jeff Moyer <jmoyer@...hat.com>
Cc:	axboe@...nel.dk, tytso@....edu, david@...morbit.com, bpm@....com,
	viro@...iv.linux.org.uk, jack@...e.cz,
	linux-fsdevel@...r.kernel.org, hch@...radead.org,
	linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
	xfs@....sgi.com
Subject: Re: [PATCH v1 0/9] fs: fix up AIO+DIO+O_SYNC to actually do the sync
 part

On Tue, Nov 20, 2012 at 09:23:18AM -0500, Jeff Moyer wrote:
> "Darrick J. Wong" <darrick.wong@...cle.com> writes:
> 
> > Hi everybody,
> >
> > On March 29th, Jeff Moyer posted to lkml a patchset with this note:
> >
> >> Currently, AIO+DIO+O_SYNC writes are not actually sync'd (for xfs), or they
> >> are sync'd before the I/O is actually issued (everybody else).  The following
> >> patch series fixes this in two parts.  First, for the file systems that use
> >> the generic routines, Jan has provided some generic infrastructure to perform
> >> the syncs after the I/O is completed.  Second, for those file systems which
> >> require some endio processing of their own for O_DIRECT writes (xfs and
> >> ext4), [Jeff] implemented file system specific syncing.  This passes the
> >> updated xfs-tests 113 test [Jeff] posted earlier, as well as all of the tests
> >> in the aio group.  [Jeff] tested ext3, ext4, xfs, and btrfs only.
> >
> > Since the original post a few months ago, this patchset doesn't seem to have
> > made any progress.  An internal testing team here discovered that the issue
> > also affects O_SYNC+AIO+DIO writes to block devices.  Worse yet, since the
> > flushes were being issued (and waited upon) directly in the io_submit call
> > graph, the io_submit calls themselves would take a very long time to complete.
> > Therefore, I added another patch to move the flush to the io_end processing.
> >
> > The blockdev patch was written by me.  The ext4 patch had to be updated to
> > accomodate a rework of the ext4 endio code that landed since March.  Everything
> > else has been passed through from Jeff's March 30th resend, with few changes.
> >
> > This patchset has been tested (albeit lightly) against 3.7-rc6 on x64, with
> > ext4, xfs, btrfs, vfat, jfs, hfsplus, ext2, ext3, and raw block devices.
> >
> > Comments and questions are, as always, welcome.
> 
> Hi, Darrick,
> 
> I just finished testing my version of this patch set on ext4 and xfs
> (btrfs is next), but you beat me to the posting!  Sorry, I should have
> been more clear when I said I would see about refreshing the series.
> 
> How have you tested these patches?  You just said "lightly", and I'm
> afraid I don't know what that means.  xfstests?  You should at least run
> them through test 113.

xfstest'd for ext4, but only sanity checked on the rest.

> Would you like to push the set in, or should I post the patches I've
> got?  Doesn't matter to me, just let me know.

Since you're the original author of most of the patches in my set anyway, would
you mind simply picking up my blockdev patch for your next submission?  It
sounds like you're a little further along in the testing than I am anyway.

--D
> 
> Cheers,
> Jeff
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