From 11e8c9b1857d272cfe6f38e83ae70478c15214eb Mon Sep 17 00:00:00 2001

From: Max Reitz <mreitz@redhat.com>

Date: Sat, 15 Feb 2014 16:03:49 +0100

Subject: [PATCH 4/5] qcow2: check for NULL l2meta

RH-Author: Max Reitz <mreitz@redhat.com>

Message-id: <1392480230-24011-4-git-send-email-mreitz@redhat.com>

Patchwork-id: 57294

O-Subject: [RHEL-7.0 qemu-kvm PATCH 3/4] qcow2: check for NULL l2meta

Bugzilla: 1055848

RH-Acked-by: Kevin Wolf <kwolf@redhat.com>

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Fam Zheng <famz@redhat.com>

From: Hu Tao <hutao@cn.fujitsu.com>

BZ: 1049176

BZ: 1055848

In the case of a metadata preallocation with a large cluster size,

qcow2_alloc_cluster_offset() can allocate nothing and returns a

NULL l2meta. This patch checks for it and link2 l2 with only valid

l2meta.

Replace 9 and 512 with BDRV_SECTOR_BITS, BDRV_SECTOR_SIZE

respectively while at the function.

Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>

Reviewed-by: Max Reitz <mreitz@redhat.com>

Reviewed-by: Benoit Canet <benoit@irqsave.net>

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

(cherry picked from commit 7c2bbf4aa66ca5a9fc2ca147e0e6cb6f407a3aa2)

Signed-off-by: Max Reitz <mreitz@redhat.com>

---

 block/qcow2.c | 31 ++++++++++++++++---------------

 1 file changed, 16 insertions(+), 15 deletions(-)

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

---

 block/qcow2.c |   31 ++++++++++++++++---------------

 1 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/block/qcow2.c b/block/qcow2.c

index fe950b4..daad932 100644

--- a/block/qcow2.c

+++ b/block/qcow2.c

@@ -1404,34 +1404,34 @@ static int preallocate(BlockDriverState *bs)

     int ret;

     QCowL2Meta *meta;

-    nb_sectors = bdrv_getlength(bs) >> 9;

+    nb_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;

     offset = 0;

     while (nb_sectors) {

-        num = MIN(nb_sectors, INT_MAX >> 9);

+        num = MIN(nb_sectors, INT_MAX >> BDRV_SECTOR_BITS);

         ret = qcow2_alloc_cluster_offset(bs, offset, &num,

                                          &host_offset, &meta);

         if (ret < 0) {

             return ret;

         }

-        ret = qcow2_alloc_cluster_link_l2(bs, meta);

-        if (ret < 0) {

-            qcow2_free_any_clusters(bs, meta->alloc_offset, meta->nb_clusters,

-                                    QCOW2_DISCARD_NEVER);

-            return ret;

-        }

-

-        /* There are no dependent requests, but we need to remove our request

-         * from the list of in-flight requests */

         if (meta != NULL) {

+            ret = qcow2_alloc_cluster_link_l2(bs, meta);

+            if (ret < 0) {

+                qcow2_free_any_clusters(bs, meta->alloc_offset,

+                                        meta->nb_clusters, QCOW2_DISCARD_NEVER);

+                return ret;

+            }

+

+            /* There are no dependent requests, but we need to remove our

+             * request from the list of in-flight requests */

             QLIST_REMOVE(meta, next_in_flight);

         }

         /* TODO Preallocate data if requested */

         nb_sectors -= num;

-        offset += num << 9;

+        offset += num << BDRV_SECTOR_BITS;

     }

     /*

@@ -1440,9 +1440,10 @@ static int preallocate(BlockDriverState *bs)

      * EOF). Extend the image to the last allocated sector.

      */

     if (host_offset != 0) {

-        uint8_t buf[512];

-        memset(buf, 0, 512);

-        ret = bdrv_write(bs->file, (host_offset >> 9) + num - 1, buf, 1);

+        uint8_t buf[BDRV_SECTOR_SIZE];

+        memset(buf, 0, BDRV_SECTOR_SIZE);

+        ret = bdrv_write(bs->file, (host_offset >> BDRV_SECTOR_BITS) + num - 1,

+                         buf, 1);

         if (ret < 0) {

             return ret;

         }

-- 

1.7.1