From ae042c767589da954f1b6c4662371dea189fcf50 Mon Sep 17 00:00:00 2001
Message-Id: <ae042c767589da954f1b6c4662371dea189fcf50.1389014116.git.minovotn@redhat.com>
In-Reply-To: <c8cc35838d42aa286242772d97e3a9be7bb786ba.1389014116.git.minovotn@redhat.com>
References: <c8cc35838d42aa286242772d97e3a9be7bb786ba.1389014116.git.minovotn@redhat.com>
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Mon, 9 Dec 2013 14:09:08 +0100
Subject: [PATCH 20/50] block/get_block_status: fix BDRV_BLOCK_ZERO for
 unallocated blocks

RH-Author: Paolo Bonzini <pbonzini@redhat.com>
Message-id: <1386598178-11845-23-git-send-email-pbonzini@redhat.com>
Patchwork-id: 56059
O-Subject: [RHEL 7.0 qemu-kvm PATCH 22/52] block/get_block_status: fix BDRV_BLOCK_ZERO for unallocated blocks
Bugzilla: 1007815
RH-Acked-by: Jeffrey Cody <jcody@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

From: Peter Lieven <pl@kamp.de>

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 <eblake@redhat.com>
Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit c3d8688470a33feb0ea78c006b4399d50c13185e)
---
 block.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Signed-off-by: Michal Novotny <minovotn@redhat.com>
---
 block.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block.c b/block.c
index 2e77763..60484a6 100644
--- a/block.c
+++ b/block.c
@@ -3290,8 +3290,8 @@ 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;
-- 
1.7.11.7