Re: [libvirt] [PATCH] Allow non-file disk backingStores

I am trying to use a qcow image with libvirt where the backing 'file' is a qemu-nbd server. Unfortunately virDomainDiskDefForeachPath() assumes that backingStore is always a real file so something like 'nbd:0:3333' is rejected because a file with that name cannot be accessed. Note that I am not worried about directly using nbd images. That would require a new disk type with XML markup, etc. I only want it to be permitted as a backingStore The following patch implements danpb's suggestion: > I think I'm inclined to push the logic for skipping NBD one stage higher. > I'd rather expect virStorageFileGetMetadata() to return all backing > stores, even if not files. The virDomainDiskDefForeachPath() method > should definitely ignore non-file backing stores though. > > So what I'm thinking is to extend the virStorageFileMetadata struct and > just add a 'bool isFile' field to it. Default this field to true, unless > you see the prefix of nbd: in which case set it to false. The > virDomainDiskDefForeachPath() method can then skip over any backing > store with isFile == false Signed-off-by: Adam Litke <agl(a)us.ibm.com&gt; Cc: Daniel P. Berrange <berrange(a)redhat.com&gt; --- src/conf/domain_conf.c | 7 +++++++ src/util/storage_file.c | 16 +++++++++++++++- src/util/storage_file.h | 1 + 3 files changed, 23 insertions(+), 1 deletions(-)

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index fe93711..2d11785 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -7813,6 +7813,13 @@ int virDomainDiskDefForeachPath(virDomainDiskDefPtr disk, depth++; nextpath = meta.backingStore; + /* Stop iterating if we reach a non-file backing store */ + if (nextpath && meta.backingStoreIsFile == false) {