From: "Darrick J. Wong" <darrick.wong@oracle.com>
Subject: Re: [PATCH v3 1/1] xfstests: generic/403: reproduce ext4 bugs in a
 shift extents logic
Date: Thu, 12 Jan 2017 11:18:50 -0800
Message-ID: <20170112191850.GI14033@birch.djwong.org>
References: <20170111095239.18825-1-roman.penyaev@profitbricks.com>
 <20170112040820.GV1859@eguan.usersys.redhat.com>
 <CAJrWOzDhdm1awxwrukzimxWGpXjD89T8fFGXabJYHvfEJEvxBQ@mail.gmail.com>
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Cc: Eryu Guan <eguan@redhat.com>, "Theodore Ts'o" <tytso@mit.edu>,
        linux-ext4@vger.kernel.org, fstests <fstests@vger.kernel.org>
To: Roman Penyaev <roman.penyaev@profitbricks.com>
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On Thu, Jan 12, 2017 at 09:02:25AM +0100, Roman Penyaev wrote:
> On Thu, Jan 12, 2017 at 5:08 AM, Eryu Guan <eguan@redhat.com> wrote:
> > On Wed, Jan 11, 2017 at 10:52:39AM +0100, Roman Pen wrote:
> >> Regression test which targets two nasty ext4 bugs in a logic which
> >> shifts extents:
> >>
> >> 1) 14d981f468a1 ("ext4: Include forgotten start block on fallocate insert range")
> >>
> >> Test tries to insert many blocks at the same offset to reproduce
> >> the following layout on ext4:
> >>
> >>    block #0  block #1
> >>    |ext0 ext1|ext2 ext3 ...|
> >>         ^
> >>      insert of a new block
> >>
> >> Because of an incorrect range first block is never reached,
> >> thus ext1 is untouched, resulting to a hole at a wrong offset:
> >>
> >> What we got:
> >>
> >>    block #0   block #1
> >>    |ext0 ext1|   ext2 ext3 ...|
> >>               ^
> >>               hole at a wrong offset
> >>
> >> What we expect:
> >>
> >>    block #0    block #1
> >>    |ext0   ext1|ext2 ext3 ...|
> >>         ^
> >>         hole at a correct offset
> >>
> >> 2) 2b3864b32403 ("ext4: do not polute the extents cache while shifting extents")
> >>
> >> Extents status tree is filled in with outdated offsets while doing
> >> extent shift, that leads to wrong data blocks.   That's why md5sum
> >> of a result file is being checked after each block insert.
> >
> > Thanks a lot! I did a minor update and queued it up.
> >
> >>
> >> Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com>
> >> Cc: "Theodore Ts'o <tytso@mit.edu>"
> >> Cc: Eryu Guan <eguan@redhat.com>
> >> Cc: linux-ext4@vger.kernel.org
> >> Cc: fstests@vger.kernel.org
> >> ---
> >
> >> +# Modify as appropriate.
> >> +_supported_fs generic
> >> +_supported_os Linux
> >> +_require_test
> >> +_require_xfs_io_command "finsert"
> >> +
> >> +blksize=`get_block_size $TEST_DIR`
> >
> > I merged a patch earlier from Darrick to rename get_block_size to
> > _get_block_size. So I did the rename here too.
> 
> Thanks.  The only thing which worries me is those commits references.
> These patches are in Theodore's dev branch and I hope SHA1 wont be
> changed.  Or maybe we have to postpone this new test till patches
> appear in mainline.  I do not know.

Please cite the subject line of the patch alongside the hash.

e.g. 'This test accompanies 9a1f4e6 ("xfs: inflate colorful balloons").'

--D

> 
> --
> Roman
> --
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