qemu: Refuse blockjobs on disk bus='sd' with -blockdev

We still have to use -drive to instantiate sd disks. Combining that with
the new logic for blockjobs would be very complicated and not worth it
given that 'sd' cards work only on few rarely used machine types of
non-common architectures and libvirt didn't implement support for 'sd'
bus controllers. This will allow us to use -blockdev for other kinds on
such machines while sacrificing block jobs.

Note: this is currently no-op as we mask-out the QEMU_CAPS_BLOCKDEV
capability if any of the disks has bus='sd'.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_backup.c

@@ -315,6 +315,9 @@ qemuBackupDiskPrepareDataOne(virDomainObjPtr vm,
         return -1;
     }
 
+    if (!qemuDomainDiskBlockJobIsSupported(vm, dd->domdisk))
+        return -1;
+
     if (!dd->store->format)
         dd->store->format = VIR_STORAGE_FILE_QCOW2;
 

src/qemu/qemu_checkpoint.c

@@ -445,6 +445,9 @@ qemuCheckpointPrepare(virQEMUDriverPtr driver,
                                vm->def->disks[i]->src->format));
             return -1;
         }
+
+        if (!qemuDomainDiskBlockJobIsSupported(vm, vm->def->disks[i]))
+            return -1;
     }
 
     return 0;

src/qemu/qemu_domain.c

@@ -13616,3 +13616,29 @@ qemuDomainInitializePflashStorageSource(virDomainObjPtr vm)
 
     return 0;
 }
+
+
+/**
+ * qemuDomainDiskBlockJobIsSupported:
+ *
+ * Returns true if block jobs are supported on @disk by @vm or false and reports
+ * an error otherwise.
+ *
+ * Note that this does not verify whether other block jobs are running etc.
+ */
+bool
+qemuDomainDiskBlockJobIsSupported(virDomainObjPtr vm,
+                                  virDomainDiskDefPtr disk)
+{
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+
+    if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV) &&
+        qemuDiskBusIsSD(disk->bus)) {
+        virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
+                       _("block jobs are not supported on disk '%s' using bus 'sd'"),
+                       disk->dst);
+        return false;
+    }
+
+    return true;
+}

src/qemu/qemu_domain.h

@@ -1293,3 +1293,7 @@ qemuDomainMakeCPUMigratable(virCPUDefPtr cpu);
 
 int
 qemuDomainInitializePflashStorageSource(virDomainObjPtr vm);
+
+bool
+qemuDomainDiskBlockJobIsSupported(virDomainObjPtr vm,
+                                  virDomainDiskDefPtr disk);

src/qemu/qemu_driver.c

@@ -14603,7 +14603,8 @@ qemuDomainSnapshotPrepareDiskExternalInactive(virDomainSnapshotDiskDefPtr snapdi
 
 
 static int
-qemuDomainSnapshotPrepareDiskExternalActive(virDomainSnapshotDiskDefPtr snapdisk,
+qemuDomainSnapshotPrepareDiskExternalActive(virDomainObjPtr vm,
+                                            virDomainSnapshotDiskDefPtr snapdisk,
                                             virDomainDiskDefPtr domdisk,
                                             bool blockdev)
 {
@@ -14616,6 +14617,9 @@ qemuDomainSnapshotPrepareDiskExternalActive(virDomainSnapshotDiskDefPtr snapdisk
         return -1;
     }
 
+    if (!qemuDomainDiskBlockJobIsSupported(vm, domdisk))
+        return -1;
+
     switch ((virStorageType)actualType) {
     case VIR_STORAGE_TYPE_BLOCK:
     case VIR_STORAGE_TYPE_FILE:
@@ -14671,7 +14675,8 @@ qemuDomainSnapshotPrepareDiskExternalActive(virDomainSnapshotDiskDefPtr snapdisk
 
 
 static int
-qemuDomainSnapshotPrepareDiskExternal(virDomainDiskDefPtr disk,
+qemuDomainSnapshotPrepareDiskExternal(virDomainObjPtr vm,
+                                      virDomainDiskDefPtr disk,
                                       virDomainSnapshotDiskDefPtr snapdisk,
                                       bool active,
                                       bool reuse,
@@ -14698,7 +14703,7 @@ qemuDomainSnapshotPrepareDiskExternal(virDomainDiskDefPtr disk,
         if (qemuDomainSnapshotPrepareDiskExternalInactive(snapdisk, disk) < 0)
             return -1;
     } else {
-        if (qemuDomainSnapshotPrepareDiskExternalActive(snapdisk, disk, blockdev) < 0)
+        if (qemuDomainSnapshotPrepareDiskExternalActive(vm, snapdisk, disk, blockdev) < 0)
             return -1;
     }
 
@@ -14857,7 +14862,7 @@ qemuDomainSnapshotPrepare(virDomainObjPtr vm,
                 return -1;
             }
 
-            if (qemuDomainSnapshotPrepareDiskExternal(dom_disk, disk,
+            if (qemuDomainSnapshotPrepareDiskExternal(vm, dom_disk, disk,
                                                       active, reuse, blockdev) < 0)
                 return -1;
 
@@ -17444,6 +17449,9 @@ qemuDomainBlockPullCommon(virDomainObjPtr vm,
     if (qemuDomainDiskBlockJobIsActive(disk))
         goto endjob;
 
+    if (!qemuDomainDiskBlockJobIsSupported(vm, disk))
+        goto endjob;
+
     if (base &&
         (virStorageFileParseChainIndex(disk->dst, base, &baseIndex) < 0 ||
          !(baseSource = virStorageFileChainLookup(disk->src, disk->src,
@@ -18002,6 +18010,9 @@ qemuDomainBlockCopyCommon(virDomainObjPtr vm,
     if (qemuDomainDiskBlockJobIsActive(disk))
         goto endjob;
 
+    if (!qemuDomainDiskBlockJobIsSupported(vm, disk))
+        goto endjob;
+
     if (disk->device == VIR_DOMAIN_DISK_DEVICE_LUN &&
         qemuDomainDefValidateDiskLunSource(mirror) < 0)
         goto endjob;
@@ -18483,6 +18494,9 @@ qemuDomainBlockCommit(virDomainPtr dom,
     if (virDomainObjCheckActive(vm) < 0)
         goto endjob;
 
+    if (!qemuDomainDiskBlockJobIsSupported(vm, disk))
+        goto endjob;
+
     blockdev = virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV);
 
     /* Convert bandwidth MiB to bytes, if necessary */