ioemu: Fix segfault when creating qcow-backed vbds.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

tools/ioemu/block-raw.c

@@ -1489,7 +1489,5 @@ BlockDriver bdrv_host_device = {
     .bdrv_pread = raw_pread,
     .bdrv_pwrite = raw_pwrite,
     .bdrv_getlength = raw_getlength,
-
-    .bdrv_flags = BLOCK_DRIVER_FLAG_EXTENDABLE
 };
 #endif /* _WIN32 */

tools/ioemu/block.c

@@ -350,11 +350,8 @@ int bdrv_open2(BlockDriverState *bs, const char *filename, int flags,
     bs->is_temporary = 0;
     bs->encrypted = 0;
 
-    if (flags & BDRV_O_EXTENDABLE) {
-	if (!(drv->bdrv_flags & BLOCK_DRIVER_FLAG_EXTENDABLE))
-	    return -ENOSYS;
+    if (flags & BDRV_O_EXTENDABLE)
 	bs->extendable = 1;
-    }
 
     if (flags & BDRV_O_SNAPSHOT) {
         BlockDriverState *bs1;

tools/ioemu/block_int.h

@@ -24,8 +24,6 @@
 #ifndef BLOCK_INT_H
 #define BLOCK_INT_H
 
-#define BLOCK_DRIVER_FLAG_EXTENDABLE  0x0001u
-
 struct BlockDriver {
     const char *format_name;
     int instance_size;
@@ -78,7 +76,6 @@ struct BlockDriver {
     int (*bdrv_eject)(BlockDriverState *bs, int eject_flag);
     int (*bdrv_set_locked)(BlockDriverState *bs, int locked);
     
-    unsigned bdrv_flags;
     BlockDriverAIOCB *free_aiocb;
     struct BlockDriver *next;
 };