[PULL 44/50] blockjob: protect iostatus field in BlockJob struct

[Kevin Wolf <kwolf@redhat.com>]

From: Emanuele Giuseppe Esposito <eesposit@redhat.com>

iostatus is the only field (together with .job) that needs
protection using the job mutex.

It is set in the main loop (GLOBAL_STATE functions) but read
in I/O code (block_job_error_action).

In order to protect it, change block_job_iostatus_set_err
to block_job_iostatus_set_err_locked(), always called under
job lock.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Message-Id: <20220926093214.506243-17-eesposit@redhat.com>
[kwolf: Fixed up type of iostatus]
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/mirror.c | 6 +++++-
 blockjob.c     | 5 +++--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/block/mirror.c b/block/mirror.c
index c6bf7f40ce..80c0109d39 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -894,6 +894,7 @@ static int coroutine_fn mirror_run(Job *job, Error **errp)
     BlockDriverState *bs = s->mirror_top_bs->backing->bs;
     BlockDriverState *target_bs = blk_bs(s->target);
     bool need_drain = true;
+    BlockDeviceIoStatus iostatus;
     int64_t length;
     int64_t target_length;
     BlockDriverInfo bdi;
@@ -1016,8 +1017,11 @@ static int coroutine_fn mirror_run(Job *job, Error **errp)
          * We do so every BLKOCK_JOB_SLICE_TIME nanoseconds, or when there is
          * an error, or when the source is clean, whichever comes first. */
         delta = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - s->last_pause_ns;
+        WITH_JOB_LOCK_GUARD() {
+            iostatus = s->common.iostatus;
+        }
         if (delta < BLOCK_JOB_SLICE_TIME &&
-            s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
+            iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
             if (s->in_flight >= MAX_IN_FLIGHT || s->buf_free_count == 0 ||
                 (cnt == 0 && s->in_flight > 0)) {
                 trace_mirror_yield(s, cnt, s->buf_free_count, s->in_flight);
diff --git a/blockjob.c b/blockjob.c
index d8fb5311c7..d04f804001 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -363,7 +363,8 @@ BlockJobInfo *block_job_query(BlockJob *job, Error **errp)
     return block_job_query_locked(job, errp);
 }
 
-static void block_job_iostatus_set_err(BlockJob *job, int error)
+/* Called with job lock held */
+static void block_job_iostatus_set_err_locked(BlockJob *job, int error)
 {
     if (job->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
         job->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
@@ -577,8 +578,8 @@ BlockErrorAction block_job_error_action(BlockJob *job, BlockdevOnError on_err,
                  */
                 job->job.user_paused = true;
             }
+            block_job_iostatus_set_err_locked(job, error);
         }
-        block_job_iostatus_set_err(job, error);
     }
     return action;
 }
-- 
2.37.3