block: Fix deadlocks in bdrv_graph_wrunlock()

[mirror_qemu.git] / block / commit.c

diff --git a/block/commit.c b/block/commit.c
index 30bc082edcef8bb9b384ef8234f47eae3068ca07..69cc75be0c329a140c73896e820e5cbe2a8c0dc3 100644 (file)
--- a/block/commit.c
+++ b/block/commit.c
@@ -95,11 +95,14 @@ 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_graph_rdlock_main_loop();
     commit_top_backing_bs = s->commit_top_bs->backing->bs;
+    bdrv_graph_rdunlock_main_loop();
+
     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_graph_wrunlock(commit_top_backing_bs);
     bdrv_drained_end(commit_top_backing_bs);
 
     bdrv_unref(s->commit_top_bs);
@@ -219,7 +222,7 @@ bdrv_commit_top_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
     return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags);
 }
 
-static void bdrv_commit_top_refresh_filename(BlockDriverState *bs)
+static GRAPH_RDLOCK void bdrv_commit_top_refresh_filename(BlockDriverState *bs)
 {
     pstrcpy(bs->exact_filename, sizeof(bs->exact_filename),
             bs->backing->bs->filename);
@@ -367,19 +370,19 @@ void commit_start(const char *job_id, BlockDriverState *bs,
         ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
                                  iter_shared_perms, errp);
         if (ret < 0) {
-            bdrv_graph_wrunlock();
+            bdrv_graph_wrunlock(top);
             goto fail;
         }
     }
 
     if (bdrv_freeze_backing_chain(commit_top_bs, base, errp) < 0) {
-        bdrv_graph_wrunlock();
+        bdrv_graph_wrunlock(top);
         goto fail;
     }
     s->chain_frozen = true;
 
     ret = block_job_add_bdrv(&s->common, "base", base, 0, BLK_PERM_ALL, errp);
-    bdrv_graph_wrunlock();
+    bdrv_graph_wrunlock(top);
 
     if (ret < 0) {
         goto fail;
@@ -433,7 +436,7 @@ fail:
         bdrv_drained_begin(top);
         bdrv_graph_wrlock(top);
         bdrv_replace_node(commit_top_bs, top, &error_abort);
-        bdrv_graph_wrunlock();
+        bdrv_graph_wrunlock(top);
         bdrv_drained_end(top);
     }
 }