block: Add block_job_add_bdrv()

When a block job is created on a certain BlockDriverState, operations
are blocked there while the job exists. However, some block jobs may
involve additional BDSs, which must be blocked separately when the job
is created and unblocked manually afterwards.

This patch adds block_job_add_bdrv(), that simplifies this process by
keeping a list of BDSs that are involved in the specified block job.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

diff --git a/blockjob.c b/blockjob.c
index 7c88b30074f0a68d065efe39e93cd33acfb6099d..422851fde5da5eb929841e6500957909a4f35e67 100644 (file)
--- a/blockjob.c
+++ b/blockjob.c
@@ -113,6 +113,13 @@ static void block_job_detach_aio_context(void *opaque)
     block_job_unref(job);
 }
 
+void block_job_add_bdrv(BlockJob *job, BlockDriverState *bs)
+{
+    job->nodes = g_slist_prepend(job->nodes, bs);
+    bdrv_ref(bs);
+    bdrv_op_block_all(bs, job->blocker);
+}
+
 void *block_job_create(const char *job_id, const BlockJobDriver *driver,
                        BlockDriverState *bs, int64_t speed,
                        BlockCompletionFunc *cb, void *opaque, Error **errp)
@@ -150,7 +157,7 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
     job = g_malloc0(driver->instance_size);
     error_setg(&job->blocker, "block device is in use by block job: %s",
                BlockJobType_lookup[driver->job_type]);
-    bdrv_op_block_all(bs, job->blocker);
+    block_job_add_bdrv(job, bs);
     bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
 
     job->driver        = driver;
@@ -189,9 +196,15 @@ void block_job_ref(BlockJob *job)
 void block_job_unref(BlockJob *job)
 {
     if (--job->refcnt == 0) {
+        GSList *l;
         BlockDriverState *bs = blk_bs(job->blk);
         bs->job = NULL;
-        bdrv_op_unblock_all(bs, job->blocker);
+        for (l = job->nodes; l; l = l->next) {
+            bs = l->data;
+            bdrv_op_unblock_all(bs, job->blocker);
+            bdrv_unref(bs);
+        }
+        g_slist_free(job->nodes);
         blk_remove_aio_context_notifier(job->blk,
                                         block_job_attached_aio_context,
                                         block_job_detach_aio_context, job);

diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index 2bb39f4d291e22e70a68106f0a48f373e3a841a8..4dfb16b43f4fedf26e50a72bf775dc956e118b8e 100644 (file)
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -188,6 +188,9 @@ struct BlockJob {
     /** Block other operations when block job is running */
     Error *blocker;
 
+    /** BlockDriverStates that are involved in this block job */
+    GSList *nodes;
+
     /** The opaque value that is passed to the completion function.  */
     void *opaque;
 
@@ -252,6 +255,17 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
                        BlockDriverState *bs, int64_t speed,
                        BlockCompletionFunc *cb, void *opaque, Error **errp);
 
+/**
+ * block_job_add_bdrv:
+ * @job: A block job
+ * @bs: A BlockDriverState that is involved in @job
+ *
+ * Add @bs to the list of BlockDriverState that are involved in
+ * @job. This means that all operations will be blocked on @bs while
+ * @job exists.
+ */
+void block_job_add_bdrv(BlockJob *job, BlockDriverState *bs);
+
 /**
  * block_job_sleep_ns:
  * @job: The job that calls the function.