Re: [PATCH] xfstests 240: test non-aligned AIO hole-filling

From: Dave Chinner <david@fromorbit.com>
To: Eric Sandeen <sandeen@redhat.com>
Cc: xfs-oss <xfs@oss.sgi.com>, ext4 development <linux-ext4@vger.kernel.org>
Subject: Re: [PATCH] xfstests 240: test non-aligned AIO hole-filling
Date: Fri, 23 Jul 2010 12:49:38 +1000	[thread overview]
Message-ID: <20100723024938.GD32635@dastard> (raw)
In-Reply-To: <4C489676.2000605@redhat.com>

On Thu, Jul 22, 2010 at 02:05:26PM -0500, Eric Sandeen wrote:
> This replicates file corruption we've seen with qemu-kvm when
> we use if=virtio,cache=none,aio=native for IO to a sparse
> ext4- or xfs-hosted file, and the partitions/filesystems
> within that file image are not block-aligned.  (think sector
> 63 here...)  This results in AIO IOs not aligned to the
> filesystem blocks.
> 
> This test modifies aiodio_sparse2.c to add an option to start
> the file IO at an offset.
> 
> When we do 4k writes to a 16k file in 2 threads, starting
> at offset 512, we get 0s interspersed in the file where they
> should not be:
> 
> 00000000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> *
> 00000200  01 01 01 01 01 01 01 01  01 01 01 01 01 01 01 01  |................|
> *
> 00001000  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
> *
> 00001200  01 01 01 01 01 01 01 01  01 01 01 01 01 01 01 01  |................|
> ....
> 
> Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

looks good - it needs to remove the $TEST_DIR/aiodio_sparse file
before the test starts, though, so that repeated tests fail
correctly. Otherwise:

Reviewed-by: Dave Chinner <dchinner@redhat.com>

Also, Eric, can you run this proof-of-concept test branch (on top of
the current XFS for-2.6.36 branch) and see if QEMU is happy with it?
It passes this test on my machine....

The following changes since commit d2ec2c790b3994bf0c4381cacc489b514705887c:

  xfs: clean up xfs_bmap_get_bp (2010-07-22 12:52:08 +1000)

are available in the git repository at:
  git://git.kernel.org/pub/scm/linux/kernel/git/dgc/xfsdev aio-unaligned

Dave Chinner (4):
      Merge branch 'master' into working
      Merge branch 'for-2.6.36' into working
      fs: get_blocks needs an unaligned mapping flag
      xfs: serialise unaligned direct IO into unwritten extents

 fs/buffer.c                 |   17 ++++++++-------
 fs/direct-io.c              |   25 ++++++++++++++++++++--
 fs/ioctl.c                  |    2 +-
 fs/mpage.c                  |    6 +++-
 fs/xfs/linux-2.6/xfs_aops.c |   47 +++++++++++++++++++++++++++++++++---------
 include/linux/fs.h          |   10 ++++++++-
 6 files changed, 82 insertions(+), 25 deletions(-)

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com