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Subject: [Qemu-devel] [PULL v3 10/35] qcow2: get rid of qcow2_backing_read1
routine
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From: Edgar Kaziakhmedov <edgar.kaziakhmedov@virtuozzo.com>
Since bdrv_co_preadv does all neccessary checks including
reading after the end of the backing file, avoid duplication
of verification before bdrv_co_preadv call.
Signed-off-by: Edgar Kaziakhmedov <edgar.kaziakhmedov@virtuozzo.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
block/qcow2.h | 3 ---
block/qcow2.c | 51 ++++++++-------------------------------------------
2 files changed, 8 insertions(+), 46 deletions(-)
diff --git a/block/qcow2.h b/block/qcow2.h
index 6f0ff15dd0..46c8cf44ec 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -528,9 +528,6 @@ uint32_t offset_to_reftable_index(BDRVQcow2State *s, ui=
nt64_t offset)
}
=20
/* qcow2.c functions */
-int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
- int64_t sector_num, int nb_sectors);
-
int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size,
int refcount_order, bool generous_inc=
rease,
uint64_t *refblock_count);
diff --git a/block/qcow2.c b/block/qcow2.c
index 1914a940e5..4348b2c0c5 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1672,34 +1672,12 @@ static int64_t coroutine_fn qcow2_co_get_block_stat=
us(BlockDriverState *bs,
return status;
}
=20
-/* handle reading after the end of the backing file */
-int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
- int64_t offset, int bytes)
-{
- uint64_t bs_size =3D bs->total_sectors * BDRV_SECTOR_SIZE;
- int n1;
-
- if ((offset + bytes) <=3D bs_size) {
- return bytes;
- }
-
- if (offset >=3D bs_size) {
- n1 =3D 0;
- } else {
- n1 =3D bs_size - offset;
- }
-
- qemu_iovec_memset(qiov, n1, 0, bytes - n1);
-
- return n1;
-}
-
static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t off=
set,
uint64_t bytes, QEMUIOVector *qiov,
int flags)
{
BDRVQcow2State *s =3D bs->opaque;
- int offset_in_cluster, n1;
+ int offset_in_cluster;
int ret;
unsigned int cur_bytes; /* number of bytes in current iteration */
uint64_t cluster_offset =3D 0;
@@ -1734,26 +1712,13 @@ static coroutine_fn int qcow2_co_preadv(BlockDriver=
State *bs, uint64_t offset,
case QCOW2_CLUSTER_UNALLOCATED:
=20
if (bs->backing) {
- /* read from the base image */
- n1 =3D qcow2_backing_read1(bs->backing->bs, &hd_qiov,
- offset, cur_bytes);
- if (n1 > 0) {
- QEMUIOVector local_qiov;
-
- qemu_iovec_init(&local_qiov, hd_qiov.niov);
- qemu_iovec_concat(&local_qiov, &hd_qiov, 0, n1);
-
- BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
- qemu_co_mutex_unlock(&s->lock);
- ret =3D bdrv_co_preadv(bs->backing, offset, n1,
- &local_qiov, 0);
- qemu_co_mutex_lock(&s->lock);
-
- qemu_iovec_destroy(&local_qiov);
-
- if (ret < 0) {
- goto fail;
- }
+ BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
+ qemu_co_mutex_unlock(&s->lock);
+ ret =3D bdrv_co_preadv(bs->backing, offset, cur_bytes,
+ &hd_qiov, 0);
+ qemu_co_mutex_lock(&s->lock);
+ if (ret < 0) {
+ goto fail;
}
} else {
/* Note: in this case, no need to wait */
--=20
2.13.6