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block/qcow2: implement .bdrv_co_preadv_part 

Implement and use new interface to get rid of hd_qiov.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-12-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-12-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2019-06-04 19:15:13 +03:00 committed by Stefan Hajnoczi
parent 00721a3529
commit df893d25ce
2 changed files with 25 additions and 29 deletions
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5
block/qcow2-cluster.c
View File

@ -452,8 +452,9 @@ static int coroutine_fn do_perform_cow_read(BlockDriverState *bs,
* interface. This avoids double I/O throttling and request tracking,
* which can lead to deadlock when block layer copy-on-read is enabled.
*/
ret = bs->drv->bdrv_co_preadv(bs, src_cluster_offset + offset_in_cluster,
qiov->size, qiov, 0);
ret = bs->drv->bdrv_co_preadv_part(bs,
src_cluster_offset + offset_in_cluster,
qiov->size, qiov, 0, 0);
if (ret < 0) {
return ret;
}

49
block/qcow2.c
View File

@ -76,7 +76,8 @@ qcow2_co_preadv_compressed(BlockDriverState *bs,
uint64_t file_cluster_offset,
uint64_t offset,
uint64_t bytes,
QEMUIOVector *qiov);
QEMUIOVector *qiov,
size_t qiov_offset);
static int qcow2_probe(const uint8_t *buf, int buf_size, const char *filename)
{
@ -1967,21 +1968,18 @@ out:
return ret;
}
static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov,
int flags)
static coroutine_fn int qcow2_co_preadv_part(BlockDriverState *bs,
uint64_t offset, uint64_t bytes,
QEMUIOVector *qiov,
size_t qiov_offset, int flags)
{
BDRVQcow2State *s = bs->opaque;
int offset_in_cluster;
int ret;
unsigned int cur_bytes; /* number of bytes in current iteration */
uint64_t cluster_offset = 0;
uint64_t bytes_done = 0;
QEMUIOVector hd_qiov;
uint8_t *cluster_data = NULL;
qemu_iovec_init(&hd_qiov, qiov->niov);
while (bytes != 0) {
/* prepare next request */
@ -2000,34 +1998,31 @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
offset_in_cluster = offset_into_cluster(s, offset);
qemu_iovec_reset(&hd_qiov);
qemu_iovec_concat(&hd_qiov, qiov, bytes_done, cur_bytes);
switch (ret) {
case QCOW2_CLUSTER_UNALLOCATED:
if (bs->backing) {
BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
ret = bdrv_co_preadv(bs->backing, offset, cur_bytes,
&hd_qiov, 0);
ret = bdrv_co_preadv_part(bs->backing, offset, cur_bytes,
qiov, qiov_offset, 0);
if (ret < 0) {
goto fail;
}
} else {
/* Note: in this case, no need to wait */
qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes);
qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes);
}
break;
case QCOW2_CLUSTER_ZERO_PLAIN:
case QCOW2_CLUSTER_ZERO_ALLOC:
qemu_iovec_memset(&hd_qiov, 0, 0, cur_bytes);
qemu_iovec_memset(qiov, qiov_offset, 0, cur_bytes);
break;
case QCOW2_CLUSTER_COMPRESSED:
ret = qcow2_co_preadv_compressed(bs, cluster_offset,
offset, cur_bytes,
&hd_qiov);
qiov, qiov_offset);
if (ret < 0) {
goto fail;
}
@ -2075,12 +2070,12 @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
ret = -EIO;
goto fail;
}
qemu_iovec_from_buf(qiov, bytes_done, cluster_data, cur_bytes);
qemu_iovec_from_buf(qiov, qiov_offset, cluster_data, cur_bytes);
} else {
BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
ret = bdrv_co_preadv(s->data_file,
cluster_offset + offset_in_cluster,
cur_bytes, &hd_qiov, 0);
ret = bdrv_co_preadv_part(s->data_file,
cluster_offset + offset_in_cluster,
cur_bytes, qiov, qiov_offset, 0);
if (ret < 0) {
goto fail;
}
@ -2095,12 +2090,11 @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
bytes -= cur_bytes;
offset += cur_bytes;
bytes_done += cur_bytes;
qiov_offset += cur_bytes;
}
ret = 0;
fail:
qemu_iovec_destroy(&hd_qiov);
qemu_vfree(cluster_data);
return ret;
@ -4101,7 +4095,8 @@ qcow2_co_preadv_compressed(BlockDriverState *bs,
uint64_t file_cluster_offset,
uint64_t offset,
uint64_t bytes,
QEMUIOVector *qiov)
QEMUIOVector *qiov,
size_t qiov_offset)
{
BDRVQcow2State *s = bs->opaque;
int ret = 0, csize, nb_csectors;
@ -4132,7 +4127,7 @@ qcow2_co_preadv_compressed(BlockDriverState *bs,
goto fail;
}
qemu_iovec_from_buf(qiov, 0, out_buf + offset_in_cluster, bytes);
qemu_iovec_from_buf(qiov, qiov_offset, out_buf + offset_in_cluster, bytes);
fail:
qemu_vfree(out_buf);
@ -4679,8 +4674,8 @@ static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
BDRVQcow2State *s = bs->opaque;
BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
return bs->drv->bdrv_co_preadv(bs, qcow2_vm_state_offset(s) + pos,
qiov->size, qiov, 0);
return bs->drv->bdrv_co_preadv_part(bs, qcow2_vm_state_offset(s) + pos,
qiov->size, qiov, 0, 0);
}
/*
@ -5222,7 +5217,7 @@ BlockDriver bdrv_qcow2 = {
.bdrv_has_zero_init_truncate = bdrv_has_zero_init_1,
.bdrv_co_block_status = qcow2_co_block_status,
.bdrv_co_preadv = qcow2_co_preadv,
.bdrv_co_preadv_part = qcow2_co_preadv_part,
.bdrv_co_pwritev = qcow2_co_pwritev,
.bdrv_co_flush_to_os = qcow2_co_flush_to_os,