block: add wrappers for logical block provisioning information
This adds 2 wrappers to read the unallocated_blocks_are_zero and
can_write_zeroes_with_unmap info from the BDI. The wrappers are
required to check for the existence of a backing_hd and
if the devices are opened with the correct flags.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/block.c b/block.c
index d34e974..3759582 100644
--- a/block.c
+++ b/block.c
@@ -3103,6 +3103,36 @@
return 0;
}
+bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs)
+{
+ BlockDriverInfo bdi;
+
+ if (bs->backing_hd) {
+ return false;
+ }
+
+ if (bdrv_get_info(bs, &bdi) == 0) {
+ return bdi.unallocated_blocks_are_zero;
+ }
+
+ return false;
+}
+
+bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs)
+{
+ BlockDriverInfo bdi;
+
+ if (bs->backing_hd || !(bs->open_flags & BDRV_O_UNMAP)) {
+ return false;
+ }
+
+ if (bdrv_get_info(bs, &bdi) == 0) {
+ return bdi.can_write_zeroes_with_unmap;
+ }
+
+ return false;
+}
+
typedef struct BdrvCoGetBlockStatusData {
BlockDriverState *bs;
BlockDriverState *base;
