Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches:

- qcow2: Fix data corruption bug that is triggered in partial cluster
  allocation with default options
- qapi: add support for blkreplay driver
- doc: Describe missing generic -blockdev options
- iotests: Fix 118 when run as root
- Minor code cleanups

# gpg: Signature made Fri 25 Oct 2019 14:19:04 BST
# gpg:                using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream:
  qcow2: Fix corruption bug in qcow2_detect_metadata_preallocation()
  coroutine: Add qemu_co_mutex_assert_locked()
  doc: Describe missing generic -blockdev options
  block/backup: drop dead code from backup_job_create
  blockdev: Use error_report() in hmp_commit()
  iotests: Skip read-only cases in 118 when run as root
  qapi: add support for blkreplay driver

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
index 8d55663..dfd261c 100644
--- a/include/qemu/coroutine.h
+++ b/include/qemu/coroutine.h
@@ -167,6 +167,21 @@ void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex);
  */
 void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex);
 
+/**
+ * Assert that the current coroutine holds @mutex.
+ */
+static inline coroutine_fn void qemu_co_mutex_assert_locked(CoMutex *mutex)
+{
+    /*
+     * mutex->holder doesn't need any synchronisation if the assertion holds
+     * true because the mutex protects it. If it doesn't hold true, we still
+     * don't mind if another thread takes or releases mutex behind our back,
+     * because the condition will be false no matter whether we read NULL or
+     * the pointer for any other coroutine.
+     */
+    assert(atomic_read(&mutex->locked) &&
+           mutex->holder == qemu_coroutine_self());
+}
 
 /**
  * CoQueues are a mechanism to queue coroutines in order to continue executing