From: "Daniel P. Berrangé" <berrange@redhat.com>
To: Nir Soffer <nsoffer@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
QEMU Developers <qemu-devel@nongnu.org>,
qemu-block <qemu-block@nongnu.org>, Max Reitz <mreitz@redhat.com>
Subject: Re: [PATCH for-5.1 1/2] block: Require aligned image size to avoid assertion failure
Date: Wed, 15 Jul 2020 15:03:19 +0100 [thread overview]
Message-ID: <20200715140319.GB88416@redhat.com> (raw)
In-Reply-To: <CAMRbyysaB5MDWGz7upg-O=N2vhQn4OUdZVsqeBothYBtZyy6ZA@mail.gmail.com>
On Wed, Jul 15, 2020 at 04:22:06PM +0300, Nir Soffer wrote:
> On Mon, Jul 13, 2020 at 7:56 PM Kevin Wolf <kwolf@redhat.com> wrote:
> >
> > Am 13.07.2020 um 18:33 hat Nir Soffer geschrieben:
> > > On Fri, Jul 10, 2020 at 5:22 PM Kevin Wolf <kwolf@redhat.com> wrote:
> > > >
> > > > Unaligned requests will automatically be aligned to bl.request_alignment
> > > > and we don't want to extend requests to access space beyond the end of
> > > > the image, so it's required that the image size is aligned.
> > > >
> > > > With write requests, this could cause assertion failures like this if
> > > > RESIZE permissions weren't requested:
> > > >
> > > > qemu-img: block/io.c:1910: bdrv_co_write_req_prepare: Assertion `end_sector <= bs->total_sectors || child->perm & BLK_PERM_RESIZE' failed.
> > > >
> > > > This was e.g. triggered by qemu-img converting to a target image with 4k
> > > > request alignment when the image was only aligned to 512 bytes, but not
> > > > to 4k.
> > >
> > > Was it on NFS? Shouldn't this be fix by the next patch then?
> >
> > Patch 2 makes the problem go away for NFS because NFS doesn't even
> > require the 4k alignment. But on storage that legitimately needs 4k
> > alignment (or possibly other filesystems that are misdetected), you
> > would still hit the same problem.
>
> I want to add oVirt point of view on this. We enforce raw image
> alignment of 4k on
> file based storage, and 128m on block storage, so our raw images cannot have
> this issue.
OpenStack should have minimium alignment of 1 GB for image sizes, so
this change is also no trouble for it.
Regards,
Daniel
--
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next prev parent reply other threads:[~2020-07-15 14:04 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-10 14:21 [PATCH for-5.1 0/2] qemu-img convert: Fix abort with unaligned image size Kevin Wolf
2020-07-10 14:21 ` [PATCH for-5.1 1/2] block: Require aligned image size to avoid assertion failure Kevin Wolf
2020-07-10 14:37 ` Eric Blake
2020-07-13 11:19 ` Max Reitz
2020-07-13 11:52 ` Max Reitz
2020-07-13 14:29 ` Kevin Wolf
2020-07-14 9:56 ` Max Reitz
2020-07-14 11:08 ` Kevin Wolf
2020-07-14 16:22 ` Max Reitz
2020-07-15 9:20 ` Kevin Wolf
2020-07-13 16:33 ` Nir Soffer
2020-07-13 16:56 ` Kevin Wolf
2020-07-15 13:22 ` Nir Soffer
2020-07-15 13:42 ` Kevin Wolf
2020-07-15 14:03 ` Nir Soffer
2020-07-15 14:03 ` Daniel P. Berrangé [this message]
2020-07-10 14:21 ` [PATCH for-5.1 2/2] file-posix: Allow byte-aligned O_DIRECT with NFS Kevin Wolf
2020-07-10 14:39 ` Eric Blake
2020-07-13 16:29 ` Nir Soffer
2020-07-10 14:43 ` [PATCH for-5.1 0/2] qemu-img convert: Fix abort with unaligned image size no-reply
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