From 95dd0c697b1b924c282cad302fc7f5af3330993d Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Fri, 18 Oct 2013 08:14:40 +0200
Subject: [PATCH 15/81] block: use bdrv_has_zero_init to return BDRV_BLOCK_ZERO

RH-Author: Paolo Bonzini <pbonzini@redhat.com>
Message-id: <1382084091-16636-16-git-send-email-pbonzini@redhat.com>
Patchwork-id: 54998
O-Subject: [RHEL 7.0 qemu-kvm PATCH 15/26] block: use bdrv_has_zero_init to return BDRV_BLOCK_ZERO
Bugzilla: 989646
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>

Alternatively, this could use a "discard zeroes data" flag returned
by bdrv_get_info.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 415b5b013ce74126e71459b922a92377918ae2ef)
---
 block.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 block.c |   11 ++++++++++-
 1 files changed, 10 insertions(+), 1 deletions(-)

diff --git a/block.c b/block.c
index 8c583bf..00bc3b2 100644
--- a/block.c
+++ b/block.c
@@ -3041,6 +3041,7 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
 {
     int64_t length;
     int64_t n;
+    int64_t ret;
 
     length = bdrv_getlength(bs);
     if (length < 0) {
@@ -3062,7 +3063,15 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
         return BDRV_BLOCK_DATA;
     }
 
-    return bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum);
+    ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum);
+    if (ret < 0) {
+        return ret;
+    }
+
+    if (!(ret & BDRV_BLOCK_DATA) && bdrv_has_zero_init(bs)) {
+        ret |= BDRV_BLOCK_ZERO;
+    }
+    return ret;
 }
 
 /* Coroutine wrapper for bdrv_get_block_status() */
-- 
1.7.1