cryptospore / rpms / qemu-kvm

Forked from rpms/qemu-kvm 2 years ago
Clone
9ae3a8
From 5bd906f28072f5d071705801cc1dd2e9084057bc Mon Sep 17 00:00:00 2001
9ae3a8
From: Max Reitz <mreitz@redhat.com>
9ae3a8
Date: Wed, 6 Nov 2013 16:53:43 +0100
9ae3a8
Subject: [PATCH 86/87] vmdk: Only read cid from image file when opening
9ae3a8
9ae3a8
RH-Author: Max Reitz <mreitz@redhat.com>
9ae3a8
Message-id: <1383756824-6921-21-git-send-email-mreitz@redhat.com>
9ae3a8
Patchwork-id: 55575
9ae3a8
O-Subject: [RHEL-7.0 qemu-kvm PATCH v2 20/21] vmdk: Only read cid from image file when opening
9ae3a8
Bugzilla: 980771
9ae3a8
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
9ae3a8
RH-Acked-by: Fam Zheng <famz@redhat.com>
9ae3a8
RH-Acked-by: Jeffrey Cody <jcody@redhat.com>
9ae3a8
9ae3a8
From: Fam Zheng <famz@redhat.com>
9ae3a8
9ae3a8
BZ: 980771
9ae3a8
9ae3a8
Previously cid of parent is parsed from image file for every IO request.
9ae3a8
We already have L1/L2 cache and don't have assumption that parent image
9ae3a8
can be updated behind us, so remove this to get more efficiency.
9ae3a8
9ae3a8
The parent CID is checked only for once after opening.
9ae3a8
9ae3a8
Signed-off-by: Fam Zheng <famz@redhat.com>
9ae3a8
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
9ae3a8
(cherry picked from commit c338b6ad609699cf352c8dd6338360b7e3895ad0)
9ae3a8
9ae3a8
Signed-off-by: Max Reitz <mreitz@redhat.com>
9ae3a8
---
9ae3a8
 block/vmdk.c | 8 +++-----
9ae3a8
 1 file changed, 3 insertions(+), 5 deletions(-)
9ae3a8
9ae3a8
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
9ae3a8
---
9ae3a8
 block/vmdk.c |    8 +++-----
9ae3a8
 1 files changed, 3 insertions(+), 5 deletions(-)
9ae3a8
9ae3a8
diff --git a/block/vmdk.c b/block/vmdk.c
9ae3a8
index ccbb0c9..8bef9f2 100644
9ae3a8
--- a/block/vmdk.c
9ae3a8
+++ b/block/vmdk.c
9ae3a8
@@ -112,6 +112,7 @@ typedef struct BDRVVmdkState {
9ae3a8
     CoMutex lock;
9ae3a8
     uint64_t desc_offset;
9ae3a8
     bool cid_updated;
9ae3a8
+    bool cid_checked;
9ae3a8
     uint32_t parent_cid;
9ae3a8
     int num_extents;
9ae3a8
     /* Extent array with num_extents entries, ascend ordered by address */
9ae3a8
@@ -197,8 +198,6 @@ static int vmdk_probe(const uint8_t *buf, int buf_size, const char *filename)
9ae3a8
     }
9ae3a8
 }
9ae3a8
 
9ae3a8
-#define CHECK_CID 1
9ae3a8
-
9ae3a8
 #define SECTOR_SIZE 512
9ae3a8
 #define DESC_SIZE (20 * SECTOR_SIZE)    /* 20 sectors of 512 bytes each */
9ae3a8
 #define BUF_SIZE 4096
9ae3a8
@@ -301,19 +300,18 @@ static int vmdk_write_cid(BlockDriverState *bs, uint32_t cid)
9ae3a8
 
9ae3a8
 static int vmdk_is_cid_valid(BlockDriverState *bs)
9ae3a8
 {
9ae3a8
-#ifdef CHECK_CID
9ae3a8
     BDRVVmdkState *s = bs->opaque;
9ae3a8
     BlockDriverState *p_bs = bs->backing_hd;
9ae3a8
     uint32_t cur_pcid;
9ae3a8
 
9ae3a8
-    if (p_bs) {
9ae3a8
+    if (!s->cid_checked && p_bs) {
9ae3a8
         cur_pcid = vmdk_read_cid(p_bs, 0);
9ae3a8
         if (s->parent_cid != cur_pcid) {
9ae3a8
             /* CID not valid */
9ae3a8
             return 0;
9ae3a8
         }
9ae3a8
     }
9ae3a8
-#endif
9ae3a8
+    s->cid_checked = true;
9ae3a8
     /* CID valid */
9ae3a8
     return 1;
9ae3a8
 }
9ae3a8
-- 
9ae3a8
1.7.1
9ae3a8