3 files changed, 71 insertions, 1 deletions

diff --git a/include/block/block.h b/include/block/block.h
index 2307f67b0e..dd8eca1be1 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -272,6 +272,7 @@ void bdrv_drain_all(void);
 
 int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors);
 int bdrv_co_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors);
+int bdrv_has_zero_init_1(BlockDriverState *bs);
 int bdrv_has_zero_init(BlockDriverState *bs);
 int bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
                       int *pnum);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index ba52247c1a..c6ac871e21 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -59,7 +59,16 @@
 #define BLOCK_OPT_LAZY_REFCOUNTS    "lazy_refcounts"
 #define BLOCK_OPT_ADAPTER_TYPE      "adapter_type"
 
-typedef struct BdrvTrackedRequest BdrvTrackedRequest;
+typedef struct BdrvTrackedRequest {
+    BlockDriverState *bs;
+    int64_t sector_num;
+    int nb_sectors;
+    bool is_write;
+    QLIST_ENTRY(BdrvTrackedRequest) list;
+    Coroutine *co; /* owner, used for deadlock detection */
+    CoQueue wait_queue; /* coroutines blocked on this request */
+} BdrvTrackedRequest;
+
 
 typedef struct BlockIOLimit {
     int64_t bps[3];
@@ -248,6 +257,9 @@ struct BlockDriverState {
 
     NotifierList close_notifiers;
 
+    /* Callback before write request is processed */
+    NotifierWithReturnList before_write_notifiers;
+
     /* number of in-flight copy-on-read requests */
     unsigned int copy_on_read_in_flight;
 
@@ -299,6 +311,15 @@ void bdrv_set_io_limits(BlockDriverState *bs,
                         BlockIOLimit *io_limits);
 
 /**
+ * bdrv_add_before_write_notifier:
+ *
+ * Register a callback that is invoked before write requests are processed but
+ * after any throttling or waiting for overlapping requests.
+ */
+void bdrv_add_before_write_notifier(BlockDriverState *bs,
+                                    NotifierWithReturn *notifier);
+
+/**
  * bdrv_get_aio_context:
  *
  * Returns: the currently bound #AioContext
@@ -378,4 +399,23 @@ void mirror_start(BlockDriverState *bs, BlockDriverState *target,
                   BlockDriverCompletionFunc *cb,
                   void *opaque, Error **errp);
 
+/*
+ * backup_start:
+ * @bs: Block device to operate on.
+ * @target: Block device to write to.
+ * @speed: The maximum speed, in bytes per second, or 0 for unlimited.
+ * @on_source_error: The action to take upon error reading from the source.
+ * @on_target_error: The action to take upon error writing to the target.
+ * @cb: Completion function for the job.
+ * @opaque: Opaque pointer value passed to @cb.
+ *
+ * Start a backup operation on @bs.  Clusters in @bs are written to @target
+ * until the job is cancelled or manually completed.
+ */
+void backup_start(BlockDriverState *bs, BlockDriverState *target,
+                  int64_t speed, BlockdevOnError on_source_error,
+                  BlockdevOnError on_target_error,
+                  BlockDriverCompletionFunc *cb, void *opaque,
+                  Error **errp);
+
 #endif /* BLOCK_INT_H */
diff --git a/include/qemu/notify.h b/include/qemu/notify.h
index 4e2e7f0ec4..a3d73e4bc7 100644
--- a/include/qemu/notify.h
+++ b/include/qemu/notify.h
@@ -40,4 +40,33 @@ void notifier_remove(Notifier *notifier);
 
 void notifier_list_notify(NotifierList *list, void *data);
 
+/* Same as Notifier but allows .notify() to return errors */
+typedef struct NotifierWithReturn NotifierWithReturn;
+
+struct NotifierWithReturn {
+    /**
+     * Return 0 on success (next notifier will be invoked), otherwise
+     * notifier_with_return_list_notify() will stop and return the value.
+     */
+    int (*notify)(NotifierWithReturn *notifier, void *data);
+    QLIST_ENTRY(NotifierWithReturn) node;
+};
+
+typedef struct NotifierWithReturnList {
+    QLIST_HEAD(, NotifierWithReturn) notifiers;
+} NotifierWithReturnList;
+
+#define NOTIFIER_WITH_RETURN_LIST_INITIALIZER(head) \
+    { QLIST_HEAD_INITIALIZER((head).notifiers) }
+
+void notifier_with_return_list_init(NotifierWithReturnList *list);
+
+void notifier_with_return_list_add(NotifierWithReturnList *list,
+                                   NotifierWithReturn *notifier);
+
+void notifier_with_return_remove(NotifierWithReturn *notifier);
+
+int notifier_with_return_list_notify(NotifierWithReturnList *list,
+                                     void *data);
+
 #endif