commit: Allow users to request only format driver names in backing file format

[mirror_qemu.git] / block / commit.c

diff --git a/block/commit.c b/block/commit.c
index d92af02ead6bba1f2b46244049ffdfa0e950422a..7c3fdcb0caeb03a000b64ba76d11bed53d34e982 100644 (file)
--- a/block/commit.c
+++ b/block/commit.c
@@ -42,6 +42,7 @@ typedef struct CommitBlockJob {
     bool base_read_only;
     bool chain_frozen;
     char *backing_file_str;
+    bool backing_mask_protocol;
 } CommitBlockJob;
 
 static int commit_prepare(Job *job)
@@ -61,13 +62,15 @@ static int commit_prepare(Job *job)
     /* FIXME: bdrv_drop_intermediate treats total failures and partial failures
      * identically. Further work is needed to disambiguate these cases. */
     return bdrv_drop_intermediate(s->commit_top_bs, s->base_bs,
-                                  s->backing_file_str);
+                                  s->backing_file_str,
+                                  s->backing_mask_protocol);
 }
 
 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();
@@ -94,8 +97,15 @@ 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);
+    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();
+    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);
@@ -214,7 +224,7 @@ 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);
@@ -246,6 +256,7 @@ void commit_start(const char *job_id, BlockDriverState *bs,
                   BlockDriverState *base, BlockDriverState *top,
                   int creation_flags, int64_t speed,
                   BlockdevOnError on_error, const char *backing_file_str,
+                  bool backing_mask_protocol,
                   const char *filter_node_name, Error **errp)
 {
     CommitBlockJob *s;
@@ -331,7 +342,7 @@ void commit_start(const char *job_id, BlockDriverState *bs,
      * this is the responsibility of the interface (i.e. whoever calls
      * commit_start()).
      */
-    bdrv_graph_wrlock(top);
+    bdrv_graph_wrlock();
     s->base_overlay = bdrv_find_overlay(top, base);
     assert(s->base_overlay);
 
@@ -400,6 +411,7 @@ void commit_start(const char *job_id, BlockDriverState *bs,
     blk_set_disable_request_queuing(s->top, true);
 
     s->backing_file_str = g_strdup(backing_file_str);
+    s->backing_mask_protocol = backing_mask_protocol;
     s->on_error = on_error;
 
     trace_commit_start(bs, base, top, s);
@@ -425,7 +437,11 @@ 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();
         bdrv_replace_node(commit_top_bs, top, &error_abort);
+        bdrv_graph_wrunlock();
+        bdrv_drained_end(top);
     }
 }