block: Mark bdrv_replace_node() GRAPH_WRLOCK

[mirror_qemu.git] / block / commit.c

diff --git a/block/commit.c b/block/commit.c
index 05eb57d9eab14817958881740bf837f4906eb173..30bc082edcef8bb9b384ef8234f47eae3068ca07 100644 (file)
--- a/block/commit.c
+++ b/block/commit.c
@@ -48,8 +48,10 @@ static int commit_prepare(Job *job)
 {
     CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
 
+    bdrv_graph_rdlock_main_loop();
     bdrv_unfreeze_backing_chain(s->commit_top_bs, s->base_bs);
     s->chain_frozen = false;
+    bdrv_graph_rdunlock_main_loop();
 
     /* Remove base node parent that still uses BLK_PERM_WRITE/RESIZE before
      * the normal backing chain can be restored. */
@@ -66,9 +68,12 @@ static void commit_abort(Job *job)
 {
     CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
     BlockDriverState *top_bs = blk_bs(s->top);
+    BlockDriverState *commit_top_backing_bs;
 
     if (s->chain_frozen) {
+        bdrv_graph_rdlock_main_loop();
         bdrv_unfreeze_backing_chain(s->commit_top_bs, s->base_bs);
+        bdrv_graph_rdunlock_main_loop();
     }
 
     /* Make sure commit_top_bs and top stay around until bdrv_replace_node() */
@@ -90,8 +95,12 @@ static void commit_abort(Job *job)
      * XXX Can (or should) we somehow keep 'consistent read' blocked even
      * after the failed/cancelled commit job is gone? If we already wrote
      * something to base, the intermediate images aren't valid any more. */
-    bdrv_replace_node(s->commit_top_bs, s->commit_top_bs->backing->bs,
-                      &error_abort);
+    commit_top_backing_bs = s->commit_top_bs->backing->bs;
+    bdrv_drained_begin(commit_top_backing_bs);
+    bdrv_graph_wrlock(commit_top_backing_bs);
+    bdrv_replace_node(s->commit_top_bs, commit_top_backing_bs, &error_abort);
+    bdrv_graph_wrunlock();
+    bdrv_drained_end(commit_top_backing_bs);
 
     bdrv_unref(s->commit_top_bs);
     bdrv_unref(top_bs);
@@ -404,7 +413,9 @@ void commit_start(const char *job_id, BlockDriverState *bs,
 
 fail:
     if (s->chain_frozen) {
+        bdrv_graph_rdlock_main_loop();
         bdrv_unfreeze_backing_chain(commit_top_bs, base);
+        bdrv_graph_rdunlock_main_loop();
     }
     if (s->base) {
         blk_unref(s->base);
@@ -419,7 +430,11 @@ fail:
     /* commit_top_bs has to be replaced after deleting the block job,
      * otherwise this would fail because of lack of permissions. */
     if (commit_top_bs) {
+        bdrv_drained_begin(top);
+        bdrv_graph_wrlock(top);
         bdrv_replace_node(commit_top_bs, top, &error_abort);
+        bdrv_graph_wrunlock();
+        bdrv_drained_end(top);
     }
 }