On Wed, Jul 15, 2020 at 04:22:06PM +0300, Nir Soffer wrote: > On Mon, Jul 13, 2020 at 7:56 PM Kevin Wolf <kw...@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 <kw...@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 -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|