Re: [PATCH] generic: test reflinked file corruption after short COW

[Eric Sandeen <sandeen@sandeen.net>]

On 9/24/20 3:17 PM, Darrick J. Wong wrote:
> On Thu, Sep 24, 2020 at 01:19:49PM -0500, Eric Sandeen wrote:
>> This test essentially creates an existing COW extent which
>> covers the first 1M, and then does another IO that overlaps it,
>> but extends beyond it.  The bug was that we did not trim the
>> new IO to the end of the existing COW extent, and so the IO
>> extended past the COW blocks and corrupted the reflinked files(s).
>>
>> The bug came and went upstream; it will be hopefully fixed in the
>> 5.4.y stable series via:
>>
>> https://lore.kernel.org/stable/e7fe7225-4f2b-d13e-bb4b-c7db68f63124@redhat.com/
>>
>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>> ---
>>
>> diff --git a/tests/generic/612 b/tests/generic/612
>> new file mode 100755
>> index 00000000..5a765a0c
>> --- /dev/null
>> +++ b/tests/generic/612
>> @@ -0,0 +1,83 @@
>> +#! /bin/bash
>> +# SPDX-License-Identifier: GPL-2.0
>> +# Copyright (c) 2020 Red Hat, Inc.  All Rights Reserved.
>> +#
>> +# FS QA Test 612
>> +#
>> +# Regression test for reflink corruption present as of:
>> +# 78f0cc9d55cb "xfs: don't use delalloc extents for COW on files with extsize hints"
>> +# and (inadvertently) fixed as of:
>> +# 36adcbace24e "xfs: fill out the srcmap in iomap_begin"
> 
> This probably should list the name of the patch that fixes it for 5.4.
> 
> With that added,
> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

Will have to wait for a merge for that, I guess.

Especially with the typo fixed (or not)

-Eric