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block/backup: use buffer-based io

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Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2019-04-22 17:58:35 +03:00 committed by Kevin Wolf
parent a4072543cc
commit 607dbdc4e0
1 changed files with 6 additions and 8 deletions
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14
block/backup.c
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@ -107,7 +107,6 @@ static int coroutine_fn backup_cow_with_bounce_buffer(BackupBlockJob *job,
void **bounce_buffer)
{
int ret;
QEMUIOVector qiov;
BlockBackend *blk = job->common.blk;
int nbytes;
int read_flags = is_write_notifier ? BDRV_REQ_NO_SERIALISING : 0;
@ -118,9 +117,8 @@ static int coroutine_fn backup_cow_with_bounce_buffer(BackupBlockJob *job,
if (!*bounce_buffer) {
*bounce_buffer = blk_blockalign(blk, job->cluster_size);
}
qemu_iovec_init_buf(&qiov, *bounce_buffer, nbytes);
ret = blk_co_preadv(blk, start, qiov.size, &qiov, read_flags);
ret = blk_co_pread(blk, start, nbytes, *bounce_buffer, read_flags);
if (ret < 0) {
trace_backup_do_cow_read_fail(job, start, ret);
if (error_is_read) {
@ -129,13 +127,13 @@ static int coroutine_fn backup_cow_with_bounce_buffer(BackupBlockJob *job,
goto fail;
}
if (qemu_iovec_is_zero(&qiov)) {
if (buffer_is_zero(*bounce_buffer, nbytes)) {
ret = blk_co_pwrite_zeroes(job->target, start,
qiov.size, write_flags | BDRV_REQ_MAY_UNMAP);
nbytes, write_flags | BDRV_REQ_MAY_UNMAP);
} else {
ret = blk_co_pwritev(job->target, start,
qiov.size, &qiov, write_flags |
(job->compress ? BDRV_REQ_WRITE_COMPRESSED : 0));
ret = blk_co_pwrite(job->target, start,
nbytes, *bounce_buffer, write_flags |
(job->compress ? BDRV_REQ_WRITE_COMPRESSED : 0));
}
if (ret < 0) {
trace_backup_do_cow_write_fail(job, start, ret);