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[PATCH for-7.2 3/5] block/mirror: Fix NULL s->job in active writes
From: |
Hanna Reitz |
Subject: |
[PATCH for-7.2 3/5] block/mirror: Fix NULL s->job in active writes |
Date: |
Wed, 9 Nov 2022 17:54:50 +0100 |
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>
---
block/mirror.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/block/mirror.c b/block/mirror.c
index 5b6f42392c..251adc5ae0 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -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
--
2.36.1