Merge remote-tracking branch 'remotes/vsementsov/tags/pull-jobs-2021-10-07-v2' into staging

mirror: Handle errors after READY cancel
v2: add small fix by Stefano, Hanna's series fixed

# gpg: Signature made Thu 07 Oct 2021 08:25:07 AM PDT
# gpg:                using RSA key 8B9C26CDB2FD147C880E86A1561F24C1F19F79FB
# gpg: Good signature from "Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 8B9C 26CD B2FD 147C 880E  86A1 561F 24C1 F19F 79FB

* remotes/vsementsov/tags/pull-jobs-2021-10-07-v2:
  iotests: Add mirror-ready-cancel-error test
  mirror: Do not clear .cancelled
  mirror: Stop active mirroring after force-cancel
  mirror: Check job_is_cancelled() earlier
  mirror: Use job_is_cancelled()
  job: Add job_cancel_requested()
  job: Do not soft-cancel after a job is done
  jobs: Give Job.force_cancel more meaning
  job: @force parameter for job_cancel_sync()
  job: Force-cancel jobs in a failed transaction
  mirror: Drop s->synced
  mirror: Keep s->synced on error
  job: Context changes in job_completed_txn_abort()
  block/aio_task: assert `max_busy_tasks` is greater than 0
  block/backup: avoid integer overflow of `max-workers`

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 22 insertions, 7 deletions

diff --git a/include/qemu/job.h b/include/qemu/job.h
index 41162ed494..6e67b6977f 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -253,8 +253,17 @@ struct JobDriver {
 
     /**
      * If the callback is not NULL, it will be invoked in job_cancel_async
+     *
+     * This function must return true if the job will be cancelled
+     * immediately without any further I/O (mandatory if @force is
+     * true), and false otherwise.  This lets the generic job layer
+     * know whether a job has been truly (force-)cancelled, or whether
+     * it is just in a special completion mode (like mirror after
+     * READY).
+     * (If the callback is NULL, the job is assumed to terminate
+     * without I/O.)
      */
-    void (*cancel)(Job *job, bool force);
+    bool (*cancel)(Job *job, bool force);
 
 
     /** Called when the job is freed */
@@ -427,9 +436,15 @@ const char *job_type_str(const Job *job);
 /** Returns true if the job should not be visible to the management layer. */
 bool job_is_internal(Job *job);
 
-/** Returns whether the job is scheduled for cancellation. */
+/** Returns whether the job is being cancelled. */
 bool job_is_cancelled(Job *job);
 
+/**
+ * Returns whether the job is scheduled for cancellation (at an
+ * indefinite point).
+ */
+bool job_cancel_requested(Job *job);
+
 /** Returns whether the job is in a completed state. */
 bool job_is_completed(Job *job);
 
@@ -506,18 +521,18 @@ void job_user_cancel(Job *job, bool force, Error **errp);
 
 /**
  * Synchronously cancel the @job.  The completion callback is called
- * before the function returns.  The job may actually complete
- * instead of canceling itself; the circumstances under which this
- * happens depend on the kind of job that is active.
+ * before the function returns.  If @force is false, the job may
+ * actually complete instead of canceling itself; the circumstances
+ * under which this happens depend on the kind of job that is active.
  *
  * Returns the return value from the job if the job actually completed
  * during the call, or -ECANCELED if it was canceled.
  *
  * Callers must hold the AioContext lock of job->aio_context.
  */
-int job_cancel_sync(Job *job);
+int job_cancel_sync(Job *job, bool force);
 
-/** Synchronously cancels all jobs using job_cancel_sync(). */
+/** Synchronously force-cancels all jobs using job_cancel_sync(). */
 void job_cancel_sync_all(void);
 
 /**