block: vhdx - add migration blocker

This blocks migration for VHDX image files, until the
functionality can be supported.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/block/vhdx.c b/block/vhdx.c
index b8aa49c..6cb0412 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -20,6 +20,7 @@
 #include "qemu/module.h"
 #include "qemu/crc32c.h"
 #include "block/vhdx.h"
+#include "migration/migration.h"
 
 
 /* Several metadata and region table data entries are identified by
@@ -159,6 +160,7 @@
     VHDXParentLocatorHeader parent_header;
     VHDXParentLocatorEntry *parent_entries;
 
+    Error *migration_blocker;
 } BDRVVHDXState;
 
 uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
@@ -806,6 +808,12 @@
 
     /* TODO: differencing files, write */
 
+    /* Disable migration when VHDX images are used */
+    error_set(&s->migration_blocker,
+            QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
+            "vhdx", bs->device_name, "live migration");
+    migrate_add_blocker(s->migration_blocker);
+
     return 0;
 fail:
     qemu_vfree(s->headers[0]);
@@ -952,6 +960,8 @@
     qemu_vfree(s->headers[1]);
     qemu_vfree(s->bat);
     qemu_vfree(s->parent_entries);
+    migrate_del_blocker(s->migration_blocker);
+    error_free(s->migration_blocker);
 }
 
 static BlockDriver bdrv_vhdx = {