Re: [Qemu-devel] [PATCH for-2.10 v2 0/5] More bdrv_getlength() fixes

[Kevin Wolf <kwolf@redhat.com>]

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Am 10.08.2017 um 17:08 hat Eric Blake geschrieben:
> On 08/10/2017 08:02 AM, Kevin Wolf wrote:
> > Am 09.08.2017 um 22:38 hat Eric Blake geschrieben:
> >> We already have a lot of bdrv_getlength() fixes in -rc2; so I think
> >> this is still okay for -rc3.
> >>
> >> v1 was here (with a typo'd subject line):
> >> https://lists.gnu.org/archive/html/qemu-devel/2017-08/msg01226.html
> >>
> >> Since v1:
> >> - patch 1: fix error message capitalization (Kevin, R-b kept)
> >> - fix locking bug in original patch 2 (Kevin)
> >> - split original patch 2 into two parts: signature update, and
> >> added error checking (Kevin)
> >> - check for unlikely integer overflow before bdrv_truncate (Jeff)
> >>
> >> 001/5:[0002] [FC] 'vpc: Check failure of bdrv_getlength()'
> >> 002/5:[down] 'qcow: Change signature of get_cluster_offset()'
> >> 003/5:[0048] [FC] 'qcow: Check failure of bdrv_getlength() and bdrv_truncate()'
> >> 004/5:[----] [--] 'qcow2: Drop debugging dump_refcounts()'
> >> 005/5:[----] [--] 'qcow2: Check failure of bdrv_getlength()'
> > 
> > Looks good to me, but as the bug is far from being critical, I'd rather
> > apply the more complex qcow1 patches only to block-next. The vpc and
> > qcow2 parts seems a lot less risky, so 2.10 should be okay for them.
> > 
> > What do you think?
> 
> The argument for NOT doing the qcow changes (patches 2 and 3): the only
> place where we are not checking for failures is part of
> get_cluster_offset() - but in all likelihood, if we were unable to
> determine or change the length of the backing file, we will have nearby
> problems that will ultimately cause failure soon enough.  Furthermore,
> it's not a regression (we've had several releases with the problem), and
> qcow is not a good format (it's painfully slow, and we strongly
> recommend qcow2 instead) - so no one will be hitting any actual bugs in
> practice.
> 
> I'll trust your judgment as maintainer, so taking just 1, 4, and 5 in
> 2.10 is fine.

Thanks, applied the patches to block and block-next, respectively.

Kevin

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