[PATCH 5/6] block/io: assert that BlockDriver->bdrv_co_*_snapshot_* are always called with graph rdlock taken

[Emanuele Giuseppe Esposito <eesposit@redhat.com>]

The only callers are other callback functions that already run with the
graph rdlock taken.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block/io.c                       | 2 ++
 include/block/block_int-common.h | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/block/io.c b/block/io.c
index 62c0b3a390..7d1d0c48b0 100644
--- a/block/io.c
+++ b/block/io.c
@@ -3449,6 +3449,7 @@ 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;
@@ -3474,6 +3475,7 @@ 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/include/block/block_int-common.h b/include/block/block_int-common.h
index 3064822508..03bd28e3c9 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -652,9 +652,12 @@ struct BlockDriver {
      * - be able to select a specific snapshot
      * - receive the snapshot's actual length (which may differ from bs's
      *   length)
+     *
+     * Called with graph rdlock taken.
      */
     int coroutine_fn (*bdrv_co_preadv_snapshot)(BlockDriverState *bs,
         int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset);
+    /* Called with graph rdlock taken. */
     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);
-- 
2.31.1