block: Create no_co_wrappers for open functions

Images can't be opened in coroutine context because opening needs to
change the block graph. Add no_co_wrappers so that coroutines have a
simple way of opening images in a BH instead.

At the same time, mark the wrapped functions as no_coroutine_fn.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230126172432.436111-3-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/meson.build

@@ -141,6 +141,7 @@ block_gen_c = custom_target('block-gen.c',
                                       '../include/block/dirty-bitmap.h',
                                       '../include/block/block_int-io.h',
                                       '../include/block/block-global-state.h',
+                                      '../include/sysemu/block-backend-global-state.h',
                                       '../include/sysemu/block-backend-io.h',
                                       'coroutines.h'
                                       ),

include/block/block-global-state.h

@@ -77,25 +77,42 @@ BlockDriverState *bdrv_insert_node(BlockDriverState *bs, QDict *node_options,
                                    int flags, Error **errp);
 int bdrv_drop_filter(BlockDriverState *bs, Error **errp);
 
-BdrvChild *bdrv_open_child(const char *filename,
-                           QDict *options, const char *bdref_key,
-                           BlockDriverState *parent,
-                           const BdrvChildClass *child_class,
-                           BdrvChildRole child_role,
-                           bool allow_none, Error **errp);
+BdrvChild * no_coroutine_fn
+bdrv_open_child(const char *filename, QDict *options, const char *bdref_key,
+                BlockDriverState *parent, const BdrvChildClass *child_class,
+                BdrvChildRole child_role, bool allow_none, Error **errp);
+
+BdrvChild * coroutine_fn no_co_wrapper
+bdrv_co_open_child(const char *filename, QDict *options, const char *bdref_key,
+                BlockDriverState *parent, const BdrvChildClass *child_class,
+                BdrvChildRole child_role, bool allow_none, Error **errp);
+
 int bdrv_open_file_child(const char *filename,
                          QDict *options, const char *bdref_key,
                          BlockDriverState *parent, Error **errp);
-BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
+
+BlockDriverState * no_coroutine_fn
+bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
+
+BlockDriverState * coroutine_fn no_co_wrapper
+bdrv_co_open_blockdev_ref(BlockdevRef *ref, Error **errp);
+
 int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
                         Error **errp);
 int bdrv_set_backing_hd_drained(BlockDriverState *bs,
                                 BlockDriverState *backing_hd,
                                 Error **errp);
 int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options,
                            const char *bdref_key, Error **errp);
-BlockDriverState *bdrv_open(const char *filename, const char *reference,
-                            QDict *options, int flags, Error **errp);
+
+BlockDriverState * no_coroutine_fn
+bdrv_open(const char *filename, const char *reference, QDict *options,
+          int flags, Error **errp);
+
+BlockDriverState * coroutine_fn no_co_wrapper
+bdrv_co_open(const char *filename, const char *reference,
+             QDict *options, int flags, Error **errp);
+
 BlockDriverState *bdrv_new_open_driver_opts(BlockDriver *drv,
                                             const char *node_name,
                                             QDict *options, int flags,

include/sysemu/block-backend-global-state.h

@@ -23,10 +23,23 @@
  */
 
 BlockBackend *blk_new(AioContext *ctx, uint64_t perm, uint64_t shared_perm);
-BlockBackend *blk_new_with_bs(BlockDriverState *bs, uint64_t perm,
-                              uint64_t shared_perm, Error **errp);
-BlockBackend *blk_new_open(const char *filename, const char *reference,
-                           QDict *options, int flags, Error **errp);
+
+BlockBackend * no_coroutine_fn
+blk_new_with_bs(BlockDriverState *bs, uint64_t perm, uint64_t shared_perm,
+                Error **errp);
+
+BlockBackend * coroutine_fn no_co_wrapper
+blk_co_new_with_bs(BlockDriverState *bs, uint64_t perm, uint64_t shared_perm,
+                   Error **errp);
+
+BlockBackend * no_coroutine_fn
+blk_new_open(const char *filename, const char *reference, QDict *options,
+             int flags, Error **errp);
+
+BlockBackend * coroutine_fn no_co_wrapper
+blk_co_new_open(const char *filename, const char *reference, QDict *options,
+                int flags, Error **errp);
+
 int blk_get_refcnt(BlockBackend *blk);
 void blk_ref(BlockBackend *blk);
 void blk_unref(BlockBackend *blk);