[Qemu-devel] [PATCHv6 14/17] block/get_block_status: fix BDRV_BLOCK_ZERO for unallocated blocks

[Peter Lieven]

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_has_discard_zeroes() 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 ebl...@redhat.com
Signed-off-by: Peter Lieven p...@kamp.de
---
 block.c |4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block.c b/block.c
index 21a992a..69a2d2b 100644
--- a/block.c
+++ b/block.c
@@ -3263,8 +3263,8 @@ 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;
-- 
1.7.9.5

Re: [Qemu-devel] [PATCHv6 14/17] block/get_block_status: fix BDRV_BLOCK_ZERO for unallocated blocks

[Paolo Bonzini]

Il 24/10/2013 08:46, Peter Lieven ha scritto:
 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_has_discard_zeroes()

... whose name became bdrv_unallocated_blocks_are_zero :)  No big deal.

Paolo

 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 ebl...@redhat.com
 Signed-off-by: Peter Lieven p...@kamp.de
 ---
  block.c |4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)
 
 diff --git a/block.c b/block.c
 index 21a992a..69a2d2b 100644
 --- a/block.c
 +++ b/block.c
 @@ -3263,8 +3263,8 @@ 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;