block: GRAPH_RDLOCK for functions only called by co_wrappers

The generated coroutine wrappers already take care to take the lock in
the non-coroutine path, and assume that the lock is already taken in the
coroutine path.

The only thing we need to do for the wrapped function is adding the
GRAPH_RDLOCK annotation. Doing so also allows us to mark the
corresponding callbacks in BlockDriver as GRAPH_RDLOCK_PTR.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20221207131838.239125-19-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

4 files changed, 23 insertions, 18 deletions

diff --git a/block.c b/block.c
index 1a82fd1..9c2ac75 100644
--- a/block.c
+++ b/block.c
@@ -5402,6 +5402,7 @@ int coroutine_fn bdrv_co_check(BlockDriverState *bs,
                                BdrvCheckResult *res, BdrvCheckMode fix)
 {
     IO_CODE();
+    assert_bdrv_graph_readable();
     if (bs->drv == NULL) {
         return -ENOMEDIUM;
     }
@@ -6617,6 +6618,7 @@ int coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs, Error **errp)
     IO_CODE();
 
     assert(!(bs->open_flags & BDRV_O_INACTIVE));
+    assert_bdrv_graph_readable();
 
     if (bs->drv->bdrv_co_invalidate_cache) {
         bs->drv->bdrv_co_invalidate_cache(bs, &local_err);
diff --git a/block/coroutines.h b/block/coroutines.h
index 48e9081..2a1e0b3 100644
--- a/block/coroutines.h
+++ b/block/coroutines.h
@@ -37,9 +37,11 @@
  * the I/O API.
  */
 
-int coroutine_fn bdrv_co_check(BlockDriverState *bs,
-                               BdrvCheckResult *res, BdrvCheckMode fix);
-int coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs, Error **errp);
+int coroutine_fn GRAPH_RDLOCK
+bdrv_co_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
+
+int coroutine_fn GRAPH_RDLOCK
+bdrv_co_invalidate_cache(BlockDriverState *bs, Error **errp);
 
 int coroutine_fn
 bdrv_co_common_block_status_above(BlockDriverState *bs,
@@ -53,10 +55,11 @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
                                   BlockDriverState **file,
                                   int *depth);
 
-int coroutine_fn bdrv_co_readv_vmstate(BlockDriverState *bs,
-                                       QEMUIOVector *qiov, int64_t pos);
-int coroutine_fn bdrv_co_writev_vmstate(BlockDriverState *bs,
-                                        QEMUIOVector *qiov, int64_t pos);
+int coroutine_fn GRAPH_RDLOCK
+bdrv_co_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
+
+int coroutine_fn GRAPH_RDLOCK
+bdrv_co_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 
 int coroutine_fn
 nbd_co_do_establish_connection(BlockDriverState *bs, bool blocking,
diff --git a/block/io.c b/block/io.c
index d160d2e..d87788d 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2697,6 +2697,7 @@ bdrv_co_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
     BlockDriverState *child_bs = bdrv_primary_bs(bs);
     int ret;
     IO_CODE();
+    assert_bdrv_graph_readable();
 
     ret = bdrv_check_qiov_request(pos, qiov->size, qiov, 0, NULL);
     if (ret < 0) {
@@ -2729,6 +2730,7 @@ bdrv_co_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
     BlockDriverState *child_bs = bdrv_primary_bs(bs);
     int ret;
     IO_CODE();
+    assert_bdrv_graph_readable();
 
     ret = bdrv_check_qiov_request(pos, qiov->size, qiov, 0, NULL);
     if (ret < 0) {
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index b1f0d88..c34c525 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -641,8 +641,8 @@ struct BlockDriver {
     /*
      * Invalidate any cached meta-data.
      */
-    void coroutine_fn (*bdrv_co_invalidate_cache)(BlockDriverState *bs,
-                                                  Error **errp);
+    void coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_invalidate_cache)(
+        BlockDriverState *bs, Error **errp);
 
     /*
      * Flushes all data for all layers by calling bdrv_co_flush for underlying
@@ -701,12 +701,11 @@ struct BlockDriver {
                                                  Error **errp);
     BlockStatsSpecific *(*bdrv_get_specific_stats)(BlockDriverState *bs);
 
-    int coroutine_fn (*bdrv_save_vmstate)(BlockDriverState *bs,
-                                          QEMUIOVector *qiov,
-                                          int64_t pos);
-    int coroutine_fn (*bdrv_load_vmstate)(BlockDriverState *bs,
-                                          QEMUIOVector *qiov,
-                                          int64_t pos);
+    int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_save_vmstate)(
+        BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
+
+    int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_load_vmstate)(
+        BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 
     /* removable device specific */
     bool (*bdrv_is_inserted)(BlockDriverState *bs);
@@ -724,9 +723,8 @@ struct BlockDriver {
      * Returns 0 for completed check, -errno for internal errors.
      * The check results are stored in result.
      */
-    int coroutine_fn (*bdrv_co_check)(BlockDriverState *bs,
-                                      BdrvCheckResult *result,
-                                      BdrvCheckMode fix);
+    int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_check)(
+        BlockDriverState *bs, BdrvCheckResult *result, BdrvCheckMode fix);
 
     void (*bdrv_debug_event)(BlockDriverState *bs, BlkdebugEvent event);