4 files changed, 36 insertions, 17 deletions
diff --git a/include/block/aio.h b/include/block/aio.h
index 7ba9bd7874..9dd61cee7e 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -42,6 +42,7 @@ void qemu_aio_unref(void *p);
 void qemu_aio_ref(void *p);
 
 typedef struct AioHandler AioHandler;
+typedef QLIST_HEAD(, AioHandler) AioHandlerList;
 typedef void QEMUBHFunc(void *opaque);
 typedef bool AioPollFn(void *opaque);
 typedef void IOHandler(void *opaque);
@@ -51,6 +52,19 @@ struct ThreadPool;
 struct LinuxAioState;
 struct LuringState;
 
+/*
+ * Each aio_bh_poll() call carves off a slice of the BH list, so that newly
+ * scheduled BHs are not processed until the next aio_bh_poll() call.  All
+ * active aio_bh_poll() calls chain their slices together in a list, so that
+ * nested aio_bh_poll() calls process all scheduled bottom halves.
+ */
+typedef QSLIST_HEAD(, QEMUBH) BHList;
+typedef struct BHListSlice BHListSlice;
+struct BHListSlice {
+    BHList bh_list;
+    QSIMPLEQ_ENTRY(BHListSlice) next;
+};
+
 struct AioContext {
     GSource source;
 
@@ -58,7 +72,10 @@ struct AioContext {
     QemuRecMutex lock;
 
     /* The list of registered AIO handlers.  Protected by ctx->list_lock. */
-    QLIST_HEAD(, AioHandler) aio_handlers;
+    AioHandlerList aio_handlers;
+
+    /* The list of AIO handlers to be deleted.  Protected by ctx->list_lock. */
+    AioHandlerList deleted_aio_handlers;
 
     /* Used to avoid unnecessary event_notifier_set calls in aio_notify;
      * accessed with atomic primitives.  If this field is 0, everything
@@ -91,8 +108,11 @@ struct AioContext {
      */
     QemuLockCnt list_lock;
 
-    /* Anchor of the list of Bottom Halves belonging to the context */
-    struct QEMUBH *first_bh;
+    /* Bottom Halves pending aio_bh_poll() processing */
+    BHList bh_list;
+
+    /* Chained BH list slices for each nested aio_bh_poll() call */
+    QSIMPLEQ_HEAD(, BHListSlice) bh_slice_list;
 
     /* Used by aio_notify.
      *
diff --git a/include/block/block.h b/include/block/block.h
index 6cd566324d..cd6b5b95aa 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -391,11 +391,6 @@ int bdrv_amend_options(BlockDriverState *bs_new, QemuOpts *opts,
                        BlockDriverAmendStatusCB *status_cb, void *cb_opaque,
                        Error **errp);
 
-/* external snapshots */
-bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
-                                      BlockDriverState *candidate);
-bool bdrv_is_first_non_filter(BlockDriverState *candidate);
-
 /* check if a named node can be replaced when doing drive-mirror */
 BlockDriverState *check_to_replace_node(BlockDriverState *parent_bs,
                                         const char *node_name, Error **errp);
@@ -459,7 +454,7 @@ void bdrv_lock_medium(BlockDriverState *bs, bool locked);
 void bdrv_eject(BlockDriverState *bs, bool eject_flag);
 const char *bdrv_get_format_name(BlockDriverState *bs);
 BlockDriverState *bdrv_find_node(const char *node_name);
-BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp);
+BlockDeviceInfoList *bdrv_named_nodes_list(bool flat, Error **errp);
 XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp);
 BlockDriverState *bdrv_lookup_bs(const char *device,
                                  const char *node_name,
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 640fb82c78..6f9fd5e20e 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -94,14 +94,13 @@ struct BlockDriver {
      * must implement them and return -ENOTSUP.
      */
     bool is_filter;
-    /* for snapshots block filter like Quorum can implement the
-     * following recursive callback.
-     * It's purpose is to recurse on the filter children while calling
-     * bdrv_recurse_is_first_non_filter on them.
-     * For a sample implementation look in the future Quorum block filter.
+    /*
+     * Return true if @to_replace can be replaced by a BDS with the
+     * same data as @bs without it affecting @bs's behavior (that is,
+     * without it being visible to @bs's parents).
      */
-    bool (*bdrv_recurse_is_first_non_filter)(BlockDriverState *bs,
-                                             BlockDriverState *candidate);
+    bool (*bdrv_recurse_can_replace)(BlockDriverState *bs,
+                                     BlockDriverState *to_replace);
 
     int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename);
     int (*bdrv_probe_device)(const char *filename);
@@ -1263,6 +1262,9 @@ void bdrv_format_default_perms(BlockDriverState *bs, BdrvChild *c,
                                uint64_t perm, uint64_t shared,
                                uint64_t *nperm, uint64_t *nshared);
 
+bool bdrv_recurse_can_replace(BlockDriverState *bs,
+                              BlockDriverState *to_replace);
+
 /*
  * Default implementation for drivers to pass bdrv_co_block_status() to
  * their file.
diff --git a/include/block/qapi.h b/include/block/qapi.h
index cd9410dee3..22c7807c89 100644
--- a/include/block/qapi.h
+++ b/include/block/qapi.h
@@ -29,7 +29,9 @@
 #include "block/snapshot.h"
 
 BlockDeviceInfo *bdrv_block_device_info(BlockBackend *blk,
-                                        BlockDriverState *bs, Error **errp);
+                                        BlockDriverState *bs,
+                                        bool flat,
+                                        Error **errp);
 int bdrv_query_snapshot_info_list(BlockDriverState *bs,
                                   SnapshotInfoList **p_list,
                                   Error **errp);