Re: [libvirt] [PATCH 6/7] storage:dir: adapts .refreshVol .refreshPool for ploop volumes

On 06/04/16 15:11, Ján Tomko wrote: > On Wed, Apr 06, 2016 at 11:18:22AM +0300, Olga Krishtal wrote: >> The thing is that if we changed the size, the content of root.hds and >> had left the old DiskDeskriptor.xml - it becomes impossible to operate. >> I mean that DiskDescriptor.xml stores this info - size, Celinders, >> Sectors, and what is more important - all information about snapshot. >> In the situation when we have uploaded previously snapshoted volume - >> the content of volume and DiskDescriptor will be inconsistent. >> And work upon such volume will be impossible. >> But if you have any idea, where such refresh of DiskDescriptor.xml could >> be done - I will be glad to know. > DiskDeskriptor should be changed at the same time as root.hds - > if libvirt does the resize/content change, it should refresh the XML as > part of the API that changes the volume. > > Libvirt's pool refresh or vol refresh should only update libvirtd's > in-memory metadata to match the on-disk state. DiskDescriptor.xml content is based on root.hsd - ploop restore-desciptor uses root.hds header. From this point of view I just copy the info from root.hds yo DD.xml > > If the on-disk state was left inconsistent by some other application, > it's a problem of that application. I don't think libvirt should be > working around that. > > Jan But what about the uploadVol. As I understand volume ulpload is asynchronous operation - I mean, that virStorageVolUpload will returned before the content will be updated: if (virStorageVolUpload(vol, st, offset, length, 0) < 0) { ------ returned from ulpoad, but I can not generate new DiskDeskriptor.xml it is too early. I need volume with new content. vshError(ctl, _("cannot upload to volume %s"), name); goto cleanup; } if (virStreamSendAll(st, cmdVolUploadSource, &fd) < 0) { ----- I can do it. Volume is ready to use. vshError(ctl, _("cannot send data to volume %s"), name); goto cleanup; } I