block/mirror: Fix NULL s->job in active writes

There is a small gap in mirror_start_job() before putting the mirror
filter node into the block graph (bdrv_append() call) and the actual job
being created.  Before the job is created, MirrorBDSOpaque.job is NULL.

It is possible that requests come in when bdrv_drained_end() is called,
and those requests would see MirrorBDSOpaque.job == NULL.  Have our
filter node handle that case gracefully.

Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20221109165452.67927-4-hreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Hanna Reitz 2022-11-09 17:54:50 +01:00 committed by Kevin Wolf
parent eb99491299
commit da93d5c84e

View File

@ -1438,11 +1438,13 @@ static int coroutine_fn bdrv_mirror_top_do_write(BlockDriverState *bs,
MirrorOp *op = NULL;
MirrorBDSOpaque *s = bs->opaque;
int ret = 0;
bool copy_to_target;
bool copy_to_target = false;
copy_to_target = s->job->ret >= 0 &&
!job_is_cancelled(&s->job->common.job) &&
s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING;
if (s->job) {
copy_to_target = s->job->ret >= 0 &&
!job_is_cancelled(&s->job->common.job) &&
s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING;
}
if (copy_to_target) {
op = active_write_prepare(s->job, offset, bytes);
@ -1487,11 +1489,13 @@ static int coroutine_fn bdrv_mirror_top_pwritev(BlockDriverState *bs,
QEMUIOVector bounce_qiov;
void *bounce_buf;
int ret = 0;
bool copy_to_target;
bool copy_to_target = false;
copy_to_target = s->job->ret >= 0 &&
!job_is_cancelled(&s->job->common.job) &&
s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING;
if (s->job) {
copy_to_target = s->job->ret >= 0 &&
!job_is_cancelled(&s->job->common.job) &&
s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING;
}
if (copy_to_target) {
/* The guest might concurrently modify the data to write; but