block: bdrv_has_zero_init
This fixes the problem that qemu-img's use of no_zero_init only considered the
no_zero_init flag of the format driver, but not of the underlying protocols.
Between the raw/file split and this fix, converting to host devices is broken.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block.c b/block.c
index eb1d562..56835af 100644
--- a/block.c
+++ b/block.c
@@ -1282,6 +1282,19 @@
}
}
+int bdrv_has_zero_init(BlockDriverState *bs)
+{
+ assert(bs->drv);
+
+ if (bs->drv->no_zero_init) {
+ return 0;
+ } else if (bs->file) {
+ return bdrv_has_zero_init(bs->file);
+ }
+
+ return 1;
+}
+
/*
* Returns true iff the specified sector is present in the disk image. Drivers
* not implementing the functionality are assumed to not support backing files,
