[PATCH v3 4/6] qemu: update the validation for transient disk option

[Masayoshi Mizuma <msys.mizuma@xxxxxxxxx>]

From: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>

Update validation of transient disk option. The option for qemu is supported
with under condistions.

- qemu has blockdev feature 
- the type is file and the format is qcow2 and raw
- writable disk

Signed-off-by: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>
---
 src/qemu/qemu_validate.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/qemu/qemu_validate.c b/src/qemu/qemu_validate.c
index 070f1c962b..9cf78ca0c9 100644
--- a/src/qemu/qemu_validate.c
+++ b/src/qemu/qemu_validate.c
@@ -2002,6 +2002,28 @@ qemuValidateDomainDeviceDefDiskSerial(const char *value)
 }
 
 
+static int
+qemuValidateDomainDeviceDefDiskTransient(const virDomainDiskDef *disk,
+                                         virQEMUCapsPtr qemuCaps)
+{
+    if ((!qemuCaps) || !virQEMUCapsGet(qemuCaps, QEMU_CAPS_BLOCKDEV))
+        return false;
+
+    if (disk->src->readonly)
+        return false;
+
+    if ((disk->src->format != VIR_STORAGE_FILE_QCOW2) &&
+        (disk->src->format != VIR_STORAGE_FILE_RAW) &&
+        (disk->src->type != VIR_STORAGE_TYPE_FILE)) {
+        return false;
+    }
+
+    if (virStorageSourceIsEmpty(disk->src))
+        return false;
+
+    return true;
+}
+
 static int
 qemuValidateDomainDeviceDefDiskFrontend(const virDomainDiskDef *disk,
                                         virQEMUCapsPtr qemuCaps)
@@ -2186,7 +2208,8 @@ qemuValidateDomainDeviceDefDiskFrontend(const virDomainDiskDef *disk,
         }
     }
 
-    if (disk->transient) {
+    if ((disk->transient) &&
+        !qemuValidateDomainDeviceDefDiskTransient(disk, qemuCaps)) {
         virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
                        _("transient disks not supported yet"));
         return -1;
-- 
2.27.0