qemu: block: Make 'slice' layer effective for 'raw' storage source

Rather than pulling the configuration of the storage slice into the
'format' layer make the 'slice' layer effective for raw disks with a
storage slice. This was made possible by the recent refactors which made
the 'format' layer optional if not needed.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>

src/qemu/qemu_block.c

@@ -1203,27 +1203,6 @@ qemuBlockStorageSourceGetFormatLUKSProps(virStorageSource *src,
 }
 
 
-static int
-qemuBlockStorageSourceGetFormatRawProps(virStorageSource *src,
-                                        virJSONValue *props)
-{
-    if (virJSONValueObjectAdd(&props, "s:driver", "raw", NULL) < 0)
-        return -1;
-
-    /* Currently only storage slices are supported. We'll have to calculate
-     * the union of the slices here if we don't want to be adding needless
-     * 'raw' nodes. */
-    if (src->sliceStorage &&
-        virJSONValueObjectAdd(&props,
-                              "U:offset", src->sliceStorage->offset,
-                              "U:size", src->sliceStorage->size,
-                              NULL) < 0)
-        return -1;
-
-    return 0;
-}
-
-
 static int
 qemuBlockStorageSourceGetCryptoProps(virStorageSource *src,
                                      virJSONValue **encprops)
@@ -1336,8 +1315,7 @@ qemuBlockStorageSourceGetBlockdevFormatProps(virStorageSource *src)
     case VIR_STORAGE_FILE_FAT:
         /* The fat layer is emulated by the storage access layer, so we need to
          * put a raw layer on top */
-        if (qemuBlockStorageSourceGetFormatRawProps(src, props) < 0)
+        driver = "raw";
-            return NULL;
         break;
 
     case VIR_STORAGE_FILE_RAW:
@@ -1345,8 +1323,7 @@ qemuBlockStorageSourceGetBlockdevFormatProps(virStorageSource *src)
             if (qemuBlockStorageSourceGetFormatLUKSProps(src, props) < 0)
                 return NULL;
         } else {
-            if (qemuBlockStorageSourceGetFormatRawProps(src, props) < 0)
+            driver = "raw";
-                return NULL;
         }
         break;
 
@@ -3295,10 +3272,7 @@ qemuBlockStorageSourceIsRaw(const virStorageSource *src)
 bool
 qemuBlockStorageSourceNeedsStorageSliceLayer(const virStorageSource *src)
 {
-    if (!src->sliceStorage)
+    return !!src->sliceStorage;
-        return false;
-
-    return !qemuBlockStorageSourceIsRaw(src);
 }
 
 
@@ -3314,9 +3288,13 @@ qemuBlockStorageSourceNeedsStorageSliceLayer(const virStorageSource *src)
  * existence of the format layer nodename.
  */
 bool
-qemuBlockStorageSourceNeedsFormatLayer(const virStorageSource *src G_GNUC_UNUSED)
+qemuBlockStorageSourceNeedsFormatLayer(const virStorageSource *src)
 {
-    /* Currently we always create a 'format' layer */
+    /* Skip 'format' layer, when a storage slice for a raw image is in use */
+    if (qemuBlockStorageSourceIsRaw(src) &&
+        src->sliceStorage)
+        return false;
+
     return true;
 }
 

tests/qemuxml2argvdata/disk-slices.x86_64-latest.args

@@ -28,8 +28,8 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-QEMUGuest1/.config \
 -boot strict=on \
 -device '{"driver":"piix3-usb-uhci","id":"usb","bus":"pci.0","addr":"0x1.0x2"}' \
 -blockdev '{"driver":"file","filename":"/var/lib/libvirt/images/raw.img","node-name":"libvirt-6-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-6-format","read-only":false,"driver":"raw","offset":0,"size":321,"file":"libvirt-6-storage"}' \
+-blockdev '{"driver":"raw","offset":0,"size":321,"file":"libvirt-6-storage","node-name":"libvirt-6-slice-sto","read-only":false}' \
--device '{"driver":"virtio-blk-pci","bus":"pci.0","addr":"0x2","drive":"libvirt-6-format","id":"virtio-disk0","bootindex":1}' \
+-device '{"driver":"virtio-blk-pci","bus":"pci.0","addr":"0x2","drive":"libvirt-6-slice-sto","id":"virtio-disk0","bootindex":1}' \
 -blockdev '{"driver":"file","filename":"/var/lib/libvirt/images/raw.img","node-name":"libvirt-5-storage","auto-read-only":true,"discard":"unmap"}' \
 -blockdev '{"driver":"raw","offset":9876,"size":123456789,"file":"libvirt-5-storage","node-name":"libvirt-5-slice-sto","auto-read-only":true,"discard":"unmap"}' \
 -blockdev '{"node-name":"libvirt-5-format","read-only":true,"driver":"qcow2","file":"libvirt-5-slice-sto","backing":null}' \
@@ -42,8 +42,8 @@ XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-QEMUGuest1/.config \
 -blockdev '{"node-name":"libvirt-3-format","read-only":false,"driver":"luks","key-secret":"libvirt-3-format-encryption-secret0","file":"libvirt-3-slice-sto"}' \
 -device '{"driver":"virtio-blk-pci","bus":"pci.0","addr":"0x4","drive":"libvirt-3-format","id":"virtio-disk2"}' \
 -blockdev '{"driver":"nvme","device":"0000:02:00.0","namespace":1,"node-name":"libvirt-2-storage","auto-read-only":true,"discard":"unmap"}' \
--blockdev '{"node-name":"libvirt-2-format","read-only":false,"driver":"raw","offset":1234,"size":321,"file":"libvirt-2-storage"}' \
+-blockdev '{"driver":"raw","offset":1234,"size":321,"file":"libvirt-2-storage","node-name":"libvirt-2-slice-sto","read-only":false}' \
--device '{"driver":"virtio-blk-pci","bus":"pci.0","addr":"0x6","drive":"libvirt-2-format","id":"virtio-disk3"}' \
+-device '{"driver":"virtio-blk-pci","bus":"pci.0","addr":"0x6","drive":"libvirt-2-slice-sto","id":"virtio-disk3"}' \
 -object '{"qom-type":"secret","id":"libvirt-1-format-encryption-secret0","data":"9eao5F8qtkGt+seB1HYivWIxbtwUu6MQtg1zpj/oDtUsPr1q8wBYM91uEHCn6j/1","keyid":"masterKey0","iv":"AAECAwQFBgcICQoLDA0ODw==","format":"base64"}' \
 -blockdev '{"driver":"nvme","device":"0001:02:00.0","namespace":2,"node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap","cache":{"direct":true,"no-flush":false}}' \
 -blockdev '{"driver":"raw","offset":1234,"size":321,"file":"libvirt-1-storage","node-name":"libvirt-1-slice-sto","auto-read-only":true,"discard":"unmap","cache":{"direct":true,"no-flush":false}}' \