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qcow2: get rid of qcow2_backing_read1 routine

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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>
This commit is contained in:
Edgar Kaziakhmedov 2017-12-12 17:40:54 +03:00 committed by Kevin Wolf
parent c200c4a470
commit 546a7dc40e
2 changed files with 8 additions and 46 deletions
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51
block/qcow2.c
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@ -1672,34 +1672,12 @@ static int64_t coroutine_fn qcow2_co_get_block_status(BlockDriverState *bs,
return status; return status;
} }
/* 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 = bs->total_sectors * BDRV_SECTOR_SIZE;
int n1;
if ((offset + bytes) <= bs_size) {
return bytes;
}
if (offset >= bs_size) {
n1 = 0;
} else {
n1 = bs_size - offset;
}
qemu_iovec_memset(qiov, n1, 0, bytes - n1);
return n1;
}
static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
uint64_t bytes, QEMUIOVector *qiov, uint64_t bytes, QEMUIOVector *qiov,
int flags) int flags)
{ {
BDRVQcow2State *s = bs->opaque; BDRVQcow2State *s = bs->opaque;
int offset_in_cluster, n1; int offset_in_cluster;
int ret; int ret;
unsigned int cur_bytes; /* number of bytes in current iteration */ unsigned int cur_bytes; /* number of bytes in current iteration */
uint64_t cluster_offset = 0; uint64_t cluster_offset = 0;
@ -1734,26 +1712,13 @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset,
case QCOW2_CLUSTER_UNALLOCATED: case QCOW2_CLUSTER_UNALLOCATED:
if (bs->backing) { if (bs->backing) {
/* read from the base image */ BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
n1 = qcow2_backing_read1(bs->backing->bs, &hd_qiov, qemu_co_mutex_unlock(&s->lock);
offset, cur_bytes); ret = bdrv_co_preadv(bs->backing, offset, cur_bytes,
if (n1 > 0) { &hd_qiov, 0);
QEMUIOVector local_qiov; qemu_co_mutex_lock(&s->lock);
if (ret < 0) {
qemu_iovec_init(&local_qiov, hd_qiov.niov); goto fail;
qemu_iovec_concat(&local_qiov, &hd_qiov, 0, n1);
BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
qemu_co_mutex_unlock(&s->lock);
ret = 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;
}
} }
} else { } else {
/* Note: in this case, no need to wait */ /* Note: in this case, no need to wait */

3
block/qcow2.h
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@ -528,9 +528,6 @@ uint32_t offset_to_reftable_index(BDRVQcow2State *s, uint64_t offset)
} }
/* qcow2.c functions */ /* 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, int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size,
int refcount_order, bool generous_increase, int refcount_order, bool generous_increase,
uint64_t *refblock_count); uint64_t *refblock_count);