nbd: Mark nbd_co_do_establish_connection() and callers GRAPH_RDLOCK

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

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230504115750.54437-11-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

2 files changed, 24 insertions, 20 deletions

diff --git a/block/coroutines.h b/block/coroutines.h
index dd9f3d4..f322668 100644
--- a/block/coroutines.h
+++ b/block/coroutines.h
@@ -61,7 +61,7 @@ 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
+int coroutine_fn GRAPH_RDLOCK
 nbd_co_do_establish_connection(BlockDriverState *bs, bool blocking,
                                Error **errp);
 
@@ -85,7 +85,8 @@ bdrv_common_block_status_above(BlockDriverState *bs,
                                int64_t *map,
                                BlockDriverState **file,
                                int *depth);
-int co_wrapper_mixed
+
+int co_wrapper_mixed_bdrv_rdlock
 nbd_do_establish_connection(BlockDriverState *bs, bool blocking, Error **errp);
 
 #endif /* BLOCK_COROUTINES_H */
diff --git a/block/nbd.c b/block/nbd.c
index d3ee256..a3f8f8a 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -322,6 +322,7 @@ int coroutine_fn nbd_co_do_establish_connection(BlockDriverState *bs,
     int ret;
     IO_CODE();
 
+    assert_bdrv_graph_readable();
     assert(!s->ioc);
 
     s->ioc = nbd_co_establish_connection(s->conn, &s->info, blocking, errp);
@@ -369,7 +370,7 @@ static bool nbd_client_connecting(BDRVNBDState *s)
 }
 
 /* Called with s->requests_lock taken.  */
-static coroutine_fn void nbd_reconnect_attempt(BDRVNBDState *s)
+static void coroutine_fn GRAPH_RDLOCK nbd_reconnect_attempt(BDRVNBDState *s)
 {
     int ret;
     bool blocking = s->state == NBD_CLIENT_CONNECTING_WAIT;
@@ -480,9 +481,9 @@ static coroutine_fn int nbd_receive_replies(BDRVNBDState *s, uint64_t handle)
     }
 }
 
-static int coroutine_fn nbd_co_send_request(BlockDriverState *bs,
-                                            NBDRequest *request,
-                                            QEMUIOVector *qiov)
+static int coroutine_fn GRAPH_RDLOCK
+nbd_co_send_request(BlockDriverState *bs, NBDRequest *request,
+                    QEMUIOVector *qiov)
 {
     BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
     int rc, i = -1;
@@ -1171,8 +1172,9 @@ static int coroutine_fn nbd_co_receive_blockstatus_reply(BDRVNBDState *s,
     return iter.ret;
 }
 
-static int coroutine_fn nbd_co_request(BlockDriverState *bs, NBDRequest *request,
-                                       QEMUIOVector *write_qiov)
+static int coroutine_fn GRAPH_RDLOCK
+nbd_co_request(BlockDriverState *bs, NBDRequest *request,
+               QEMUIOVector *write_qiov)
 {
     int ret, request_ret;
     Error *local_err = NULL;
@@ -1208,9 +1210,9 @@ static int coroutine_fn nbd_co_request(BlockDriverState *bs, NBDRequest *request
     return ret ? ret : request_ret;
 }
 
-static int coroutine_fn nbd_client_co_preadv(BlockDriverState *bs, int64_t offset,
-                                             int64_t bytes, QEMUIOVector *qiov,
-                                             BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+nbd_client_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                     QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
     int ret, request_ret;
     Error *local_err = NULL;
@@ -1266,9 +1268,9 @@ static int coroutine_fn nbd_client_co_preadv(BlockDriverState *bs, int64_t offse
     return ret ? ret : request_ret;
 }
 
-static int coroutine_fn nbd_client_co_pwritev(BlockDriverState *bs, int64_t offset,
-                                              int64_t bytes, QEMUIOVector *qiov,
-                                              BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+nbd_client_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                      QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
     BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
     NBDRequest request = {
@@ -1291,8 +1293,9 @@ static int coroutine_fn nbd_client_co_pwritev(BlockDriverState *bs, int64_t offs
     return nbd_co_request(bs, &request, qiov);
 }
 
-static int coroutine_fn nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
-                                                    int64_t bytes, BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                            BdrvRequestFlags flags)
 {
     BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
     NBDRequest request = {
@@ -1326,7 +1329,7 @@ static int coroutine_fn nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_
     return nbd_co_request(bs, &request, NULL);
 }
 
-static int coroutine_fn nbd_client_co_flush(BlockDriverState *bs)
+static int coroutine_fn GRAPH_RDLOCK nbd_client_co_flush(BlockDriverState *bs)
 {
     BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
     NBDRequest request = { .type = NBD_CMD_FLUSH };
@@ -1341,8 +1344,8 @@ static int coroutine_fn nbd_client_co_flush(BlockDriverState *bs)
     return nbd_co_request(bs, &request, NULL);
 }
 
-static int coroutine_fn nbd_client_co_pdiscard(BlockDriverState *bs, int64_t offset,
-                                               int64_t bytes)
+static int coroutine_fn GRAPH_RDLOCK
+nbd_client_co_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes)
 {
     BDRVNBDState *s = (BDRVNBDState *)bs->opaque;
     NBDRequest request = {
@@ -1361,7 +1364,7 @@ static int coroutine_fn nbd_client_co_pdiscard(BlockDriverState *bs, int64_t off
     return nbd_co_request(bs, &request, NULL);
 }
 
-static int coroutine_fn nbd_client_co_block_status(
+static int coroutine_fn GRAPH_RDLOCK nbd_client_co_block_status(
         BlockDriverState *bs, bool want_zero, int64_t offset, int64_t bytes,
         int64_t *pnum, int64_t *map, BlockDriverState **file)
 {