On Fri, Oct 02, 2020 at 08:19:43AM -0500, Eric Sandeen wrote:
> On 10/2/20 8:07 AM, Sasha Levin wrote:
> > 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@xxxxxxxxxxxxxxx> # 5.4.x
> >> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> >> Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> >> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> >> ---
> >>
> >> 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.
>
> Thansk Sasha - the reviews/acks were given for V1 (hch & darrick), V2
> adds them to the commit log (see above) and fixes a typo in the
> subject.
Still looks ok ;)
Still-Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
--D
>
> Thanks,
> -Eric
>
