diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index 29b230cc0b..7d8309ba5a 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -624,11 +624,13 @@ struct BlockDriver {
      * - receive the snapshot's actual length (which may differ from bs's
      *   length)
      */
-    int coroutine_fn (*bdrv_co_preadv_snapshot)(BlockDriverState *bs,
-        int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset);
-    int coroutine_fn (*bdrv_co_snapshot_block_status)(BlockDriverState *bs,
-        bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum,
-        int64_t *map, BlockDriverState **file);
+    int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_preadv_snapshot)(
+        BlockDriverState *bs, int64_t offset, int64_t bytes,
+        QEMUIOVector *qiov, size_t qiov_offset);
+
+    int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_snapshot_block_status)(
+        BlockDriverState *bs, bool want_zero, int64_t offset, int64_t bytes,
+        int64_t *pnum, int64_t *map, BlockDriverState **file);
 
     int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_pdiscard_snapshot)(
         BlockDriverState *bs, int64_t offset, int64_t bytes);
diff --git a/include/block/block_int-io.h b/include/block/block_int-io.h
index 5788bd66ba..612e5ddf99 100644
--- a/include/block/block_int-io.h
+++ b/include/block/block_int-io.h
@@ -35,11 +35,11 @@
  * the I/O API.
  */
 
-int coroutine_fn bdrv_co_preadv_snapshot(BdrvChild *child,
+int coroutine_fn GRAPH_RDLOCK bdrv_co_preadv_snapshot(BdrvChild *child,
     int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset);
-int coroutine_fn bdrv_co_snapshot_block_status(BlockDriverState *bs,
-    bool want_zero, int64_t offset, int64_t bytes, int64_t *pnum,
-    int64_t *map, BlockDriverState **file);
+int coroutine_fn GRAPH_RDLOCK bdrv_co_snapshot_block_status(
+    BlockDriverState *bs, bool want_zero, int64_t offset, int64_t bytes,
+    int64_t *pnum, int64_t *map, BlockDriverState **file);
 int coroutine_fn GRAPH_RDLOCK bdrv_co_pdiscard_snapshot(BlockDriverState *bs,
     int64_t offset, int64_t bytes);
 
diff --git a/block/copy-before-write.c b/block/copy-before-write.c
index e223e37300..646d8227a4 100644
--- a/block/copy-before-write.c
+++ b/block/copy-before-write.c
@@ -256,7 +256,7 @@ cbw_snapshot_read_unlock(BlockDriverState *bs, BlockReq *req)
     g_free(req);
 }
 
-static coroutine_fn int
+static int coroutine_fn GRAPH_RDLOCK
 cbw_co_preadv_snapshot(BlockDriverState *bs, int64_t offset, int64_t bytes,
                        QEMUIOVector *qiov, size_t qiov_offset)
 {
@@ -264,8 +264,6 @@ cbw_co_preadv_snapshot(BlockDriverState *bs, int64_t offset, int64_t bytes,
     BdrvChild *file;
     int ret;
 
-    assume_graph_lock(); /* FIXME */
-
     /* TODO: upgrade to async loop using AioTask */
     while (bytes) {
         int64_t cur_bytes;
@@ -290,7 +288,7 @@ cbw_co_preadv_snapshot(BlockDriverState *bs, int64_t offset, int64_t bytes,
     return 0;
 }
 
-static int coroutine_fn
+static int coroutine_fn GRAPH_RDLOCK
 cbw_co_snapshot_block_status(BlockDriverState *bs,
                              bool want_zero, int64_t offset, int64_t bytes,
                              int64_t *pnum, int64_t *map,
diff --git a/block/io.c b/block/io.c
index 86e5ea362d..d9c1594960 100644
--- a/block/io.c
+++ b/block/io.c
@@ -3532,6 +3532,7 @@ bdrv_co_preadv_snapshot(BdrvChild *child, int64_t offset, int64_t bytes,
     BlockDriver *drv = bs->drv;
     int ret;
     IO_CODE();
+    assert_bdrv_graph_readable();
 
     if (!drv) {
         return -ENOMEDIUM;
@@ -3557,6 +3558,7 @@ bdrv_co_snapshot_block_status(BlockDriverState *bs,
     BlockDriver *drv = bs->drv;
     int ret;
     IO_CODE();
+    assert_bdrv_graph_readable();
 
     if (!drv) {
         return -ENOMEDIUM;
diff --git a/block/snapshot-access.c b/block/snapshot-access.c
index 009cc4aea0..67ea339da9 100644
--- a/block/snapshot-access.c
+++ b/block/snapshot-access.c
@@ -26,7 +26,7 @@
 #include "qemu/cutils.h"
 #include "block/block_int.h"
 
-static coroutine_fn int
+static int coroutine_fn GRAPH_RDLOCK
 snapshot_access_co_preadv_part(BlockDriverState *bs,
                                int64_t offset, int64_t bytes,
                                QEMUIOVector *qiov, size_t qiov_offset,
@@ -39,7 +39,7 @@ snapshot_access_co_preadv_part(BlockDriverState *bs,
     return bdrv_co_preadv_snapshot(bs->file, offset, bytes, qiov, qiov_offset);
 }
 
-static int coroutine_fn
+static int coroutine_fn GRAPH_RDLOCK
 snapshot_access_co_block_status(BlockDriverState *bs,
                                 bool want_zero, int64_t offset,
                                 int64_t bytes, int64_t *pnum,
