getstats: report block sizes for offline domains

The prior refactoring can now be put to use. With the same domain
as the earlier commit 7b499262 (one qcow2 disk and an empty
cdrom drive):
$ virsh domstats --block foo
Domain: 'foo'
  block.count=2
  block.0.name=hda
  block.0.path=/var/lib/libvirt/images/foo.qcow2
  block.0.allocation=1309614080
  block.0.capacity=42949672960
  block.0.physical=1309671424
  block.1.name=hdc

* src/qemu/qemu_driver.c (qemuDomainGetStatsBlock): Use
qemuStorageLimitsRefresh to report offline statistics.
Signed-off-by: NEric Blake <eblake@redhat.com>

src/qemu/qemu_driver.c

@@ -18565,6 +18565,7 @@ qemuDomainGetStatsBlock(virQEMUDriverPtr driver,
     virHashTablePtr stats = NULL;
     qemuDomainObjPrivatePtr priv = dom->privateData;
     bool abbreviated = false;
+    virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
 
     if (!HAVE_JOB(privflags) || !virDomainObjIsActive(dom)) {
         abbreviated = true; /* it's ok, just go ahead silently */
@@ -18594,8 +18595,19 @@ qemuDomainGetStatsBlock(virQEMUDriverPtr driver,
 
         if (abbreviated || !disk->info.alias ||
             !(entry = virHashLookup(stats, disk->info.alias))) {
-            /* FIXME: we could still look up sizing by sharing code
-             * with qemuDomainGetBlockInfo */
+            if (virStorageSourceIsEmpty(disk->src))
+                continue;
+            if (qemuStorageLimitsRefresh(driver, cfg, dom, disk->src) < 0)
+                goto cleanup;
+            if (disk->src->allocation)
+                QEMU_ADD_BLOCK_PARAM_ULL(record, maxparams, i,
+                                         "allocation", disk->src->allocation);
+            if (disk->src->capacity)
+                QEMU_ADD_BLOCK_PARAM_ULL(record, maxparams, i,
+                                         "capacity", disk->src->capacity);
+            if (disk->src->physical)
+                QEMU_ADD_BLOCK_PARAM_ULL(record, maxparams, i,
+                                         "physical", disk->src->physical);
             continue;
         }
 
@@ -18632,6 +18644,7 @@ qemuDomainGetStatsBlock(virQEMUDriverPtr driver,
 
  cleanup:
     virHashFree(stats);
+    virObjectUnref(cfg);
     return ret;
 }