From 287b4d4a189c0108ef926539f9b6325734a79b1d Mon Sep 17 00:00:00 2001
Message-Id: <287b4d4a189c0108ef926539f9b6325734a79b1d.1334770230.git.minovotn@redhat.com>
In-Reply-To: <5e4659718c6d6ee9ab11b269d929a292a71b3ab0.1334770230.git.minovotn@redhat.com>
References: <5e4659718c6d6ee9ab11b269d929a292a71b3ab0.1334770230.git.minovotn@redhat.com>
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Fri, 13 Apr 2012 16:27:17 +0200
Subject: [PATCH 09/18] block: fix allocation size for dirty bitmap
RH-Author: Paolo Bonzini <pbonzini@redhat.com>
Message-id: <1334334446-31987-8-git-send-email-pbonzini@redhat.com>
Patchwork-id: 39220
O-Subject: [RHEL 6.3 qemu-kvm PATCH 07/16] block: fix allocation size for dirty bitmap
Bugzilla: 806432
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Jeffrey Cody <jcody@redhat.com>
Bugzilla: 806432
Upstream status: submitted for inclusion in 1.1
Also reuse elsewhere the new constant for sizeof(unsigned long) * 8.
The dirty bitmap is allocated in bits but declared as unsigned long.
Thus, its memory block is accessed beyond its end unless the image
is a multiple of 64 chunks (i.e. a multiple of 64 MB).
---
block.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
Signed-off-by: Michal Novotny <minovotn@redhat.com>
---
block.c | 12 +++++++-----
1 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/block.c b/block.c
index 5ad176a..d6d2b57 100644
--- a/block.c
+++ b/block.c
@@ -1369,6 +1369,8 @@ int bdrv_read(BlockDriverState *bs, int64_t sector_num,
return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false);
}
+#define BITS_PER_LONG (sizeof(unsigned long) * 8)
+
static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, int dirty)
{
@@ -1379,8 +1381,8 @@ static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num,
end = (sector_num + nb_sectors - 1) / BDRV_SECTORS_PER_DIRTY_CHUNK;
for (; start <= end; start++) {
- idx = start / (sizeof(unsigned long) * 8);
- bit = start % (sizeof(unsigned long) * 8);
+ idx = start / BITS_PER_LONG;
+ bit = start % BITS_PER_LONG;
val = bs->dirty_bitmap[idx];
if (dirty) {
if (!(val & (1UL << bit))) {
@@ -3422,10 +3424,10 @@ void bdrv_set_dirty_tracking(BlockDriverState *bs, int enable)
if (enable) {
if (!bs->dirty_bitmap) {
bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS) +
- BDRV_SECTORS_PER_DIRTY_CHUNK * 8 - 1;
- bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * 8;
+ BDRV_SECTORS_PER_DIRTY_CHUNK * BITS_PER_LONG - 1;
+ bitmap_size /= BDRV_SECTORS_PER_DIRTY_CHUNK * BITS_PER_LONG;
- bs->dirty_bitmap = g_malloc0(bitmap_size);
+ bs->dirty_bitmap = g_new0(unsigned long, bitmap_size);
}
} else {
if (bs->dirty_bitmap) {
--
1.7.7.6