[Qemu-devel] [PATCH v3 1/2] block: add the support to drain throttled requests

[zwu.kernel@gmail.com]

From: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
---
 block.c     |   21 ++++++++++++++++++++-
 block_int.h |    1 +
 2 files changed, 21 insertions(+), 1 deletions(-)

diff --git a/block.c b/block.c
index 52ffe14..b3cbcc3 100644
--- a/block.c
+++ b/block.c
@@ -853,6 +853,20 @@ void bdrv_close_all(void)
     }
 }
 
+/**
+ * Complete all pending requests for a block device
+ */
+void bdrv_drain(BlockDriverState *bs)
+{
+    do {
+        qemu_co_queue_restart_all(&bs->throttled_reqs);
+        qemu_aio_flush();
+    } while (!qemu_co_queue_empty(&bs->throttled_reqs));
+
+    assert(QLIST_EMPTY(&bs->tracked_requests));
+    assert(qemu_co_queue_empty(&bs->throttled_reqs));
+}
+
 /*
  * Wait for pending requests to complete across all BlockDriverStates
  *
@@ -863,7 +877,12 @@ void bdrv_drain_all(void)
 {
     BlockDriverState *bs;
 
-    qemu_aio_flush();
+    QTAILQ_FOREACH(bs, &bdrv_states, list) {
+        do {
+            qemu_co_queue_restart_all(&bs->throttled_reqs);
+            qemu_aio_flush();
+        } while (!qemu_co_queue_empty(&bs->throttled_reqs));
+    }
 
     /* If requests are still pending there is a bug somewhere */
     QTAILQ_FOREACH(bs, &bdrv_states, list) {
diff --git a/block_int.h b/block_int.h
index b460c36..c624399 100644
--- a/block_int.h
+++ b/block_int.h
@@ -318,6 +318,7 @@ void qemu_aio_release(void *p);
 
 void bdrv_set_io_limits(BlockDriverState *bs,
                         BlockIOLimit *io_limits);
+void bdrv_drain(BlockDriverState *bs);
 
 #ifdef _WIN32
 int is_windows_drive(const char *filename);
-- 
1.7.6