qemu: blockjob: Ensure that config disk source is identical when modifying it

qemuBlockJobRewriteConfigDiskSource rewrites the disk source only
according to the 'target'. This means that if someone would change the
inactive config of the VM to refer to a different disk a block job would
rewrite it when finishing a job which modifies the disk source.

Make sure that this does not happen by verifying that the source of the
config disk is the same.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
ACKed-by: Eric Blake <eblake@redhat.com>

diff --git a/src/qemu/qemu_blockjob.c b/src/qemu/qemu_blockjob.c
index 487ef24d5c380ba633750a09762d1b0c906b537c..1e19347b03a88f2a397b9acd3883f0529cab572c 100644 (file)
--- a/src/qemu/qemu_blockjob.c
+++ b/src/qemu/qemu_blockjob.c
@@ -479,6 +479,9 @@ qemuBlockJobRewriteConfigDiskSource(virDomainObjPtr vm,
     if (!(persistDisk = virDomainDiskByName(vm->newDef, disk->dst, false)))
         return;
 
+    if (!virStorageSourceIsSameLocation(disk->src, persistDisk->src))
+        return;
+
     if (!(copy = virStorageSourceCopy(newsrc, false)) ||
         virStorageSourceInitChainElement(copy, persistDisk->src, true) < 0) {
         VIR_WARN("Unable to update persistent definition on vm %s after block job",