From 68066d2b824a88a45b3263dd1ceb18307c92581f Mon Sep 17 00:00:00 2001

From: Max Reitz <mreitz@redhat.com>

Date: Sat, 15 Feb 2014 16:03:47 +0100

Subject: [PATCH 2/5] qcow2: remove n_start and n_end of qcow2_alloc_cluster_offset()

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

Message-id: <1392480230-24011-2-git-send-email-mreitz@redhat.com>

Patchwork-id: 57292

O-Subject: [RHEL-7.0 qemu-kvm PATCH 1/4] qcow2: remove n_start and n_end of qcow2_alloc_cluster_offset()

Bugzilla: 1049176

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

n_start can be actually calculated from offset. The number of

sectors to be allocated(n_end - n_start) can be passed in in

num. By removing n_start and n_end, we can save two parameters.

The side effect is there is a bug in qcow2.c:preallocate() that

passes incorrect n_start to qcow2_alloc_cluster_offset() is

fixed. The bug can be triggerred by a larger cluster size than

the default value(65536), for example:

./qemu-img create -f qcow2 \

  -o 'cluster_size=131072,preallocation=metadata' file.img 4G

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 16f0587e0a5da5b1ad76cb7c3739491bc042201c)

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

---

 block/qcow2-cluster.c | 14 ++++++--------

 block/qcow2.c         | 13 +++++++------

 block/qcow2.h         |  2 +-

 trace-events          |  2 +-

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

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

---

 block/qcow2-cluster.c |   14 ++++++--------

 block/qcow2.c         |   13 +++++++------

 block/qcow2.h         |    2 +-

 trace-events          |    2 +-

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

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

index 79c3ae0..862df0f 100644

--- a/block/qcow2-cluster.c

+++ b/block/qcow2-cluster.c

@@ -1173,7 +1173,7 @@ fail:

  * Return 0 on success and -errno in error cases

  */

 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,

-    int n_start, int n_end, int *num, uint64_t *host_offset, QCowL2Meta **m)

+    int *num, uint64_t *host_offset, QCowL2Meta **m)

 {

     BDRVQcowState *s = bs->opaque;

     uint64_t start, remaining;

@@ -1181,15 +1181,13 @@ int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,

     uint64_t cur_bytes;

     int ret;

-    trace_qcow2_alloc_clusters_offset(qemu_coroutine_self(), offset,

-                                      n_start, n_end);

+    trace_qcow2_alloc_clusters_offset(qemu_coroutine_self(), offset, *num);

-    assert(n_start * BDRV_SECTOR_SIZE == offset_into_cluster(s, offset));

-    offset = start_of_cluster(s, offset);

+    assert((offset & ~BDRV_SECTOR_MASK) == 0);

 again:

-    start = offset + (n_start << BDRV_SECTOR_BITS);

-    remaining = (n_end - n_start) << BDRV_SECTOR_BITS;

+    start = offset;

+    remaining = *num << BDRV_SECTOR_BITS;

     cluster_offset = 0;

     *host_offset = 0;

     cur_bytes = 0;

@@ -1275,7 +1273,7 @@ again:

         }

     }

-    *num = (n_end - n_start) - (remaining >> BDRV_SECTOR_BITS);

+    *num -= remaining >> BDRV_SECTOR_BITS;

     assert(*num > 0);

     assert(*host_offset != 0);

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

index 25a5b5e..fe950b4 100644

--- a/block/qcow2.c

+++ b/block/qcow2.c

@@ -1000,7 +1000,6 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,

 {

     BDRVQcowState *s = bs->opaque;

     int index_in_cluster;

-    int n_end;

     int ret;

     int cur_nr_sectors; /* number of sectors in current iteration */

     uint64_t cluster_offset;

@@ -1024,14 +1023,16 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,

         trace_qcow2_writev_start_part(qemu_coroutine_self());

         index_in_cluster = sector_num & (s->cluster_sectors - 1);

-        n_end = index_in_cluster + remaining_sectors;

+        cur_nr_sectors = remaining_sectors;

         if (s->crypt_method &&

-            n_end > QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors) {

-            n_end = QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors;

+            cur_nr_sectors >

+            QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster) {

+            cur_nr_sectors =

+                QCOW_MAX_CRYPT_CLUSTERS * s->cluster_sectors - index_in_cluster;

         }

         ret = qcow2_alloc_cluster_offset(bs, sector_num << 9,

-            index_in_cluster, n_end, &cur_nr_sectors, &cluster_offset, &l2meta);

+            &cur_nr_sectors, &cluster_offset, &l2meta);

         if (ret < 0) {

             goto fail;

         }

@@ -1408,7 +1409,7 @@ static int preallocate(BlockDriverState *bs)

     while (nb_sectors) {

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

-        ret = qcow2_alloc_cluster_offset(bs, offset, 0, num, &num,

+        ret = qcow2_alloc_cluster_offset(bs, offset, &num,

                                          &host_offset, &meta);

         if (ret < 0) {

             return ret;

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

index 9749f03..4a653c5 100644

--- a/block/qcow2.h

+++ b/block/qcow2.h

@@ -463,7 +463,7 @@ void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,

 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,

     int *num, uint64_t *cluster_offset);

 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,

-    int n_start, int n_end, int *num, uint64_t *host_offset, QCowL2Meta **m);

+    int *num, uint64_t *host_offset, QCowL2Meta **m);

 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,

                                          uint64_t offset,

                                          int compressed_size);

diff --git a/trace-events b/trace-events

index 5d86cf3..b9144b2 100644

--- a/trace-events

+++ b/trace-events

@@ -485,7 +485,7 @@ qcow2_writev_done_part(void *co, int cur_nr_sectors) "co %p cur_nr_sectors %d"

 qcow2_writev_data(void *co, uint64_t offset) "co %p offset %" PRIx64

 # block/qcow2-cluster.c

-qcow2_alloc_clusters_offset(void *co, uint64_t offset, int n_start, int n_end) "co %p offet %" PRIx64 " n_start %d n_end %d"

+qcow2_alloc_clusters_offset(void *co, uint64_t offset, int num) "co %p offet %" PRIx64 " num %d"

 qcow2_handle_copied(void *co, uint64_t guest_offset, uint64_t host_offset, uint64_t bytes) "co %p guest_offet %" PRIx64 " host_offset %" PRIx64 " bytes %" PRIx64

 qcow2_handle_alloc(void *co, uint64_t guest_offset, uint64_t host_offset, uint64_t bytes) "co %p guest_offet %" PRIx64 " host_offset %" PRIx64 " bytes %" PRIx64

 qcow2_do_alloc_clusters_offset(void *co, uint64_t guest_offset, uint64_t host_offset, int nb_clusters) "co %p guest_offet %" PRIx64 " host_offset %" PRIx64 " nb_clusters %d"

-- 

1.7.1