From: Christoph Hellwig <hch@lst.de>
To: Eric Sandeen <sandeen@redhat.com>
Cc: xfs <linux-xfs@vger.kernel.org>,
stable@vger.kernel.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH STABLE] xfs: trim IO to found COW exent limit
Date: Thu, 24 Sep 2020 06:03:27 +0200 [thread overview]
Message-ID: <20200924040327.GA8078@lst.de> (raw)
In-Reply-To: <e7fe7225-4f2b-d13e-bb4b-c7db68f63124@redhat.com>
On Wed, Sep 23, 2020 at 05:35:44PM -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>
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
and as Darrick said we'll want to wire up the reproducer for xfstests.
prev parent reply other threads:[~2020-09-24 4:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-23 22:35 [PATCH STABLE] xfs: trim IO to found COW exent limit Eric Sandeen
2020-09-23 22:37 ` Eric Sandeen
2020-09-23 22:59 ` Darrick J. Wong
2020-09-23 23:53 ` Eric Sandeen
2020-09-23 22:58 ` Darrick J. Wong
2020-09-24 4:03 ` Christoph Hellwig [this message]
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