block: Mark bdrv_co_pdiscard() and callers GRAPH_RDLOCK

This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_co_pdiscard() need to hold a reader lock for the graph.

For some places, we know that they will hold the lock, but we don't have
the GRAPH_RDLOCK annotations yet. In this case, add assume_graph_lock()
with a FIXME comment. These places will be removed once everything is
properly annotated.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230203152202.49054-9-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/block/io.c b/block/io.c
index cfc93dc..e97adb5 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2971,6 +2971,7 @@ int coroutine_fn bdrv_co_pdiscard(BdrvChild *child, int64_t offset,
     int head, tail, align;
     BlockDriverState *bs = child->bs;
     IO_CODE();
+    assert_bdrv_graph_readable();
 
     if (!bs || !bs->drv || !bdrv_co_is_inserted(bs)) {
         return -ENOMEDIUM;
@@ -3577,6 +3578,7 @@ bdrv_co_pdiscard_snapshot(BlockDriverState *bs, int64_t offset, int64_t bytes)
     BlockDriver *drv = bs->drv;
     int ret;
     IO_CODE();
+    assert_bdrv_graph_readable();
 
     if (!drv) {
         return -ENOMEDIUM;