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From 53d8964bc0e80e99d5ccb15100ecb93a7b5f74b0 Mon Sep 17 00:00:00 2001
Message-Id: <53d8964bc0e80e99d5ccb15100ecb93a7b5f74b0.1389014116.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 14:08:58 +0100
Subject: [PATCH 10/50] block: add wrappers for logical block provisioning
 information

RH-Author: Paolo Bonzini <pbonzini@redhat.com>
Message-id: <1386598178-11845-13-git-send-email-pbonzini@redhat.com>
Patchwork-id: 56050
O-Subject: [RHEL 7.0 qemu-kvm PATCH 12/52] block: add wrappers for logical block provisioning information
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 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>
(cherry picked from commit 4ce786914b745a144a9eda1ea33f3ff98328c527)
---
 block.c               | 30 ++++++++++++++++++++++++++++++
 include/block/block.h |  2 ++
 2 files changed, 32 insertions(+)

Signed-off-by: Michal Novotny <minovotn@redhat.com>
---
 block.c               | 30 ++++++++++++++++++++++++++++++
 include/block/block.h |  2 ++
 2 files changed, 32 insertions(+)

diff --git a/block.c b/block.c
index 77167f0..2fae459 100644
--- a/block.c
+++ b/block.c
@@ -3121,6 +3121,36 @@ int bdrv_has_zero_init(BlockDriverState *bs)
     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;
diff --git a/include/block/block.h b/include/block/block.h
index ab3044e..1958d98 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -330,6 +330,8 @@ int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors);
 int bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors);
 int bdrv_has_zero_init_1(BlockDriverState *bs);
 int bdrv_has_zero_init(BlockDriverState *bs);
+bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs);
+bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs);
 int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num,
                               int nb_sectors, int *pnum);
 int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
-- 
1.7.11.7