Re: [libvirt] [PATCH v4 2/4] storage: report error rather than warning if backing files doesn't exist

On Tue, Jul 16, 2013 at 08:14:54AM +0200, Martin Kletzander wrote: > On 07/15/2013 05:31 PM, Ján Tomko wrote: >> On 07/02/2013 11:35 AM, Guannan Ren wrote: >>> If one of backing files for disk source doesn't exist, the guest will not >>> be able to find and use the disk even though the disk still exists in >>> guest xml definition. So reporting an error make more sense. >>> >>> Adding virFileAccessibleAs() to check if the backing file described in >>> disk meta exist in real path. If not, report error. the uid and gid >>> arguments don't have so much meannings for F_OK, so give 0 for them. >>> --- >>> src/util/virstoragefile.c | 23 +++++++++++++++-------- >>> tests/virstoragetest.c | 16 ++++++++-------- >>> 2 files changed, 23 insertions(+), 16 deletions(-) >>> >>> diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c >>> index 27aa4fe..cb61e5b 100644 >>> --- a/src/util/virstoragefile.c >>> +++ b/src/util/virstoragefile.c >> >>> @@ -870,14 +877,10 @@ virStorageFileGetMetadataInternal(const char *path, >>> !!directory, backing, >>> &meta->directory, >>> &meta->backingStore) < 0) { >>> - /* the backing file is (currently) unavailable, treat this >>> - * file as standalone: >>> - * backingStoreRaw is kept to mark broken image chains */ >>> - meta->backingStoreIsFile = false; >>> - backingFormat = VIR_STORAGE_FILE_NONE; >>> - VIR_WARN("Backing file '%s' of image '%s' is missing.", >>> - meta->backingStoreRaw, path); >>> - >>> + VIR_ERROR(_("Backing file '%s' of image '%s' is missing."), >>> + meta->backingStoreRaw, path); >>> + VIR_FREE(backing); >>> + goto cleanup; >>> } >>> } >>> VIR_FREE(backing); >> >> This change means you won't be able to start the pool if one of the files is >> missing a backing file. I've forwarded a patch [1] from/for [2] that ignores >> missing files on pool start and there is a bug [3] requesting that we ignore >> other files as well. I feel like this is going in the other direction. >> >> Wouldn't it be enough to check for them on domain start-up and leave the pool >> running even if one of those volumes doesn't have an existing backing file? >> > > How about making it configurable for the pool? There are definitely > some users who want the pool to reflect actual info after pool-refresh. I don't think this needs to be configurable. The pool should show *every* single file, regardless of whether the file has a broken backing file. We shouldn't be trying to second guess what the user wants to do with a image with broken backing file. Just expose as much info as we have and let them deal with the problem.