From 69813093427b02a4a0e02264abd1f851f2b49249 Mon Sep 17 00:00:00 2001

From: Paolo Bonzini <pbonzini@redhat.com>

Date: Thu, 7 Nov 2013 07:23:45 +0100

Subject: [PATCH 26/81] block/get_block_status: avoid redundant callouts on raw devices

RH-Author: Paolo Bonzini <pbonzini@redhat.com>

Message-id: <1382084091-16636-27-git-send-email-pbonzini@redhat.com>

Patchwork-id: 55009

O-Subject: [RHEL 7.0 qemu-kvm PATCH 26/26] block/get_block_status: avoid redundant callouts on raw devices

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>

From: Peter Lieven <pl@kamp.de>

if a raw device like an iscsi target or host device is used

the current implementation makes a second call out to get

the block status of bs->file.

Signed-off-by: Peter Lieven <pl@kamp.de>

Reviewed-by: Eric Blake <eblake@redhat.com>

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

(cherry picked from commit 92bc50a5ad7fbc9a0bd17240eaea5027a100ca79)

Conflicts:

	block/raw_bsd.c

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 block.c               |    6 ++++++

 block/raw.c           |    4 +++-

 include/block/block.h |    4 ++++

 3 files changed, 13 insertions(+), 1 deletions(-)

diff --git a/block.c b/block.c

index 5c49461..fdff92f 100644

--- a/block.c

+++ b/block.c

@@ -3073,6 +3073,12 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,

         return ret;

     }

+    if (ret & BDRV_BLOCK_RAW) {

+        assert(ret & BDRV_BLOCK_OFFSET_VALID);

+        return bdrv_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS,

+                                     *pnum, pnum);

+    }

+

     if (!(ret & BDRV_BLOCK_DATA)) {

         if (bdrv_has_zero_init(bs)) {

             ret |= BDRV_BLOCK_ZERO;

diff --git a/block/raw.c b/block/raw.c

index 844a222..7d82cf3 100644

--- a/block/raw.c

+++ b/block/raw.c

@@ -39,7 +39,9 @@ static int64_t coroutine_fn raw_co_get_block_status(BlockDriverState *bs,

                                             int64_t sector_num,

                                             int nb_sectors, int *pnum)

 {

-    return bdrv_get_block_status(bs->file, sector_num, nb_sectors, pnum);

+    *pnum = nb_sectors;

+    return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID | BDRV_BLOCK_DATA |

+           (sector_num << BDRV_SECTOR_BITS);

 }

 static int coroutine_fn raw_co_write_zeroes(BlockDriverState *bs,

diff --git a/include/block/block.h b/include/block/block.h

index 01f5c65..bc1f5f6 100644

--- a/include/block/block.h

+++ b/include/block/block.h

@@ -95,6 +95,9 @@ typedef struct BlockDevOps {

 /* BDRV_BLOCK_DATA: data is read from bs->file or another file

  * BDRV_BLOCK_ZERO: sectors read as zero

  * BDRV_BLOCK_OFFSET_VALID: sector stored in bs->file as raw data

+ * BDRV_BLOCK_RAW: used internally to indicate that the request

+ *                 was answered by the raw driver and that one

+ *                 should look in bs->file directly.

  *

  * If BDRV_BLOCK_OFFSET_VALID is set, bits 9-62 represent the offset in

  * bs->file where sector data can be read from as raw data.

@@ -116,6 +119,7 @@ typedef struct BlockDevOps {

 #define BDRV_BLOCK_DATA         1

 #define BDRV_BLOCK_ZERO         2

 #define BDRV_BLOCK_OFFSET_VALID 4

+#define BDRV_BLOCK_RAW          8

 #define BDRV_BLOCK_OFFSET_MASK  BDRV_SECTOR_MASK

 typedef enum {

-- 

1.7.1