[Qemu-devel] [PULL 15/41] block/get_block_status: fix BDRV_BLOCK_ZERO for unallocated blocks

[Kevin Wolf]

From: Peter Lieven <address@hidden>

this patch does 2 things:
a) only do additional call outs if BDRV_BLOCK_ZERO is not already set.
b) use the newly introduced bdrv_unallocated_blocks_are_zero()
   to return the zero state of an unallocated block. the used callout
   to bdrv_has_zero_init() is only valid right after bdrv_create.

Reviewed-by: Eric Blake <address@hidden>
Signed-off-by: Peter Lieven <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
 block.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block.c b/block.c
index c390f20..e22b55f 100644
--- a/block.c
+++ b/block.c
@@ -3272,8 +3272,8 @@ static int64_t coroutine_fn 
bdrv_co_get_block_status(BlockDriverState *bs,
                                      *pnum, pnum);
     }
 
-    if (!(ret & BDRV_BLOCK_DATA)) {
-        if (bdrv_has_zero_init(bs)) {
+    if (!(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO)) {
+        if (bdrv_unallocated_blocks_are_zero(bs)) {
             ret |= BDRV_BLOCK_ZERO;
         } else if (bs->backing_hd) {
             BlockDriverState *bs2 = bs->backing_hd;
-- 
1.8.1.4