From: Sasha Levin <sashal@kernel.org>
To: Eric Sandeen <sandeen@sandeen.net>
Cc: xfs <linux-xfs@vger.kernel.org>,
stable@vger.kernel.org, gregkh@linuxfoundation.org
Subject: Re: [PATCH STABLE V2] xfs: trim IO to found COW extent limit
Date: Fri, 2 Oct 2020 09:07:40 -0400 [thread overview]
Message-ID: <20201002130740.GF2415204@sasha-vm> (raw)
In-Reply-To: <5d2f4fc1-e498-c45e-3d57-9c2d7ac275e6@sandeen.net>
On Thu, Oct 01, 2020 at 08:34:48AM -0500, Eric Sandeen wrote:
>A bug existed in the XFS reflink code between v5.1 and v5.5 in which
>the mapping for a COW IO was not trimmed to the mapping of the COW
>extent that was found. This resulted in a too-short copy, and
>corruption of other files which shared the original extent.
>
>(This happened only when extent size hints were set, which bypasses
>delalloc and led to this code path.)
>
>This was (inadvertently) fixed upstream with
>
>36adcbace24e "xfs: fill out the srcmap in iomap_begin"
>
>and related patches which moved lots of this functionality to
>the iomap subsystem.
>
>Hence, this is a -stable only patch, targeted to fix this
>corruption vector without other major code changes.
>
>Fixes: 78f0cc9d55cb ("xfs: don't use delalloc extents for COW on files with extsize hints")
>Cc: <stable@vger.kernel.org> # 5.4.x
>Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
>Reviewed-by: Christoph Hellwig <hch@lst.de>
>---
>
>V2: Fix typo in subject, add reviewers
>
>I've tested this with a targeted reproducer (in next email) as well as
>with xfstests.
>
>There is also now a testcase for xfstests submitted upstream
>
>Stable folk, not sure how to send a "stable only" patch, or if that's even
>valid. Assuming you're willing to accept it, I would still like to have
>some formal Reviewed-by's from the xfs developer community before it gets
>merged.
This is perfect stable-process-wise :) Will wait for reviews/acks before
merging.
--
Thanks,
Sasha
next prev parent reply other threads:[~2020-10-02 13:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-01 13:34 [PATCH STABLE V2] xfs: trim IO to found COW extent limit Eric Sandeen
2020-10-02 13:07 ` Sasha Levin [this message]
2020-10-02 13:19 ` Eric Sandeen
2020-10-02 15:58 ` Darrick J. Wong
2020-10-02 23:17 ` Sasha Levin
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