Merge remote-tracking branch 'stefanha/block' into staging

# By Stefan Hajnoczi (14) and others
# Via Stefan Hajnoczi
* stefanha/block: (28 commits)
  blockdev: Fix up copyright and permission notice
  qemu-iotests: use -nographic in test case 007
  qemu-iotests: add tests for rebasing zero clusters
  dataplane: fix hang introduced by AioContext transition
  coroutine: use AioContext for CoQueue BH
  threadpool: drop global thread pool
  block: add bdrv_get_aio_context()
  aio: add a ThreadPool instance to AioContext
  threadpool: add thread_pool_new() and thread_pool_free()
  threadpool: move globals into struct ThreadPool
  main-loop: add qemu_get_aio_context()
  sheepdog: set io_flush handler in do_co_req
  sheepdog: use non-blocking fd in coroutine context
  qcow2: make is_allocated return true for zero clusters
  qcow2: drop unnecessary flush in qcow2_update_snapshot_refcount()
  qcow2: drop flush in update_cluster_refcount()
  qcow2: flush in qcow2_update_snapshot_refcount()
  qcow2: set L2 cache dependency in qcow2_alloc_bytes()
  qcow2: flush refcount cache correctly in qcow2_write_snapshots()
  qcow2: flush refcount cache correctly in alloc_refcount_block()
  ...

1 files changed, 11 insertions, 0 deletions

diff --git a/async.c b/async.c
index f2d47ba96d..90fe906539 100644
--- a/async.c
+++ b/async.c
@@ -24,6 +24,7 @@
 
 #include "qemu-common.h"
 #include "block/aio.h"
+#include "block/thread-pool.h"
 #include "qemu/main-loop.h"
 
 /***********************************************************/
@@ -172,6 +173,7 @@ aio_ctx_finalize(GSource     *source)
 {
     AioContext *ctx = (AioContext *) source;
 
+    thread_pool_free(ctx->thread_pool);
     aio_set_event_notifier(ctx, &ctx->notifier, NULL, NULL);
     event_notifier_cleanup(&ctx->notifier);
     g_array_free(ctx->pollfds, TRUE);
@@ -190,6 +192,14 @@ GSource *aio_get_g_source(AioContext *ctx)
     return &ctx->source;
 }
 
+ThreadPool *aio_get_thread_pool(AioContext *ctx)
+{
+    if (!ctx->thread_pool) {
+        ctx->thread_pool = thread_pool_new(ctx);
+    }
+    return ctx->thread_pool;
+}
+
 void aio_notify(AioContext *ctx)
 {
     event_notifier_set(&ctx->notifier);
@@ -200,6 +210,7 @@ AioContext *aio_context_new(void)
     AioContext *ctx;
     ctx = (AioContext *) g_source_new(&aio_source_funcs, sizeof(AioContext));
     ctx->pollfds = g_array_new(FALSE, FALSE, sizeof(GPollFD));
+    ctx->thread_pool = NULL;
     event_notifier_init(&ctx->notifier, false);
     aio_set_event_notifier(ctx, &ctx->notifier, 
                            (EventNotifierHandler *)