block: Mark bdrv_co_is_inserted() and callers GRAPH_RDLOCK

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

blk_is_inserted() is done as a co_wrapper_mixed_bdrv_rdlock (unlike most
other blk_* functions) because it is called a lot from other blk_co_*()
functions that already hold the lock. These calls go through
blk_is_available(), which becomes a co_wrapper_mixed_bdrv_rdlock, too,
for the same reason.

Functions that run in a coroutine and can call bdrv_co_is_available()
directly are changed to do so, which results in better TSA coverage.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230203152202.49054-19-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

5 files changed, 23 insertions, 17 deletions

diff --git a/block.c b/block.c
index 484f48ae2d..738b42046c 100644
--- a/block.c
+++ b/block.c
@@ -6826,6 +6826,7 @@ bool coroutine_fn bdrv_co_is_inserted(BlockDriverState *bs)
     BlockDriver *drv = bs->drv;
     BdrvChild *child;
     IO_CODE();
+    assert_bdrv_graph_readable();
 
     if (!drv) {
         return false;
diff --git a/block/block-backend.c b/block/block-backend.c
index 3661a066b3..20af699f00 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1235,8 +1235,8 @@ void blk_set_disable_request_queuing(BlockBackend *blk, bool disable)
     blk->disable_request_queuing = disable;
 }
 
-static coroutine_fn int blk_check_byte_request(BlockBackend *blk,
-                                               int64_t offset, int64_t bytes)
+static int coroutine_fn GRAPH_RDLOCK
+blk_check_byte_request(BlockBackend *blk, int64_t offset, int64_t bytes)
 {
     int64_t len;
 
@@ -1244,7 +1244,7 @@ static coroutine_fn int blk_check_byte_request(BlockBackend *blk,
         return -EIO;
     }
 
-    if (!blk_is_available(blk)) {
+    if (!blk_co_is_available(blk)) {
         return -ENOMEDIUM;
     }
 
@@ -1606,8 +1606,9 @@ BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset,
 int64_t coroutine_fn blk_co_getlength(BlockBackend *blk)
 {
     IO_CODE();
+    GRAPH_RDLOCK_GUARD();
 
-    if (!blk_is_available(blk)) {
+    if (!blk_co_is_available(blk)) {
         return -ENOMEDIUM;
     }
 
@@ -1627,8 +1628,9 @@ void blk_get_geometry(BlockBackend *blk, uint64_t *nb_sectors_ptr)
 int64_t coroutine_fn blk_co_nb_sectors(BlockBackend *blk)
 {
     IO_CODE();
+    GRAPH_RDLOCK_GUARD();
 
-    if (!blk_is_available(blk)) {
+    if (!blk_co_is_available(blk)) {
         return -ENOMEDIUM;
     }
 
@@ -1676,7 +1678,7 @@ blk_co_do_ioctl(BlockBackend *blk, unsigned long int req, void *buf)
     blk_wait_while_drained(blk);
     GRAPH_RDLOCK_GUARD();
 
-    if (!blk_is_available(blk)) {
+    if (!blk_co_is_available(blk)) {
         return -ENOMEDIUM;
     }
 
@@ -1769,7 +1771,7 @@ static int coroutine_fn blk_co_do_flush(BlockBackend *blk)
     blk_wait_while_drained(blk);
     GRAPH_RDLOCK_GUARD();
 
-    if (!blk_is_available(blk)) {
+    if (!blk_co_is_available(blk)) {
         return -ENOMEDIUM;
     }
 
@@ -1996,14 +1998,15 @@ bool coroutine_fn blk_co_is_inserted(BlockBackend *blk)
 {
     BlockDriverState *bs = blk_bs(blk);
     IO_CODE();
+    assert_bdrv_graph_readable();
 
     return bs && bdrv_co_is_inserted(bs);
 }
 
-bool blk_is_available(BlockBackend *blk)
+bool coroutine_fn blk_co_is_available(BlockBackend *blk)
 {
     IO_CODE();
-    return blk_is_inserted(blk) && !blk_dev_is_tray_open(blk);
+    return blk_co_is_inserted(blk) && !blk_dev_is_tray_open(blk);
 }
 
 void coroutine_fn blk_co_lock_medium(BlockBackend *blk, bool locked)
@@ -2382,7 +2385,7 @@ int coroutine_fn blk_co_truncate(BlockBackend *blk, int64_t offset, bool exact,
 {
     IO_OR_GS_CODE();
     GRAPH_RDLOCK_GUARD();
-    if (!blk_is_available(blk)) {
+    if (!blk_co_is_available(blk)) {
         error_setg(errp, "No medium inserted");
         return -ENOMEDIUM;
     }
@@ -2637,6 +2640,7 @@ int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in,
 {
     int r;
     IO_CODE();
+    GRAPH_RDLOCK_GUARD();
 
     r = blk_check_byte_request(blk_in, off_in, bytes);
     if (r) {
@@ -2647,7 +2651,6 @@ int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in,
         return r;
     }
 
-    GRAPH_RDLOCK_GUARD();
     return bdrv_co_copy_range(blk_in->root, off_in,
                               blk_out->root, off_out,
                               bytes, read_flags, write_flags);
diff --git a/include/block/block-io.h b/include/block/block-io.h
index b8f99741a3..88db63492a 100644
--- a/include/block/block-io.h
+++ b/include/block/block-io.h
@@ -145,8 +145,8 @@ bool bdrv_is_writable(BlockDriverState *bs);
 bool bdrv_is_sg(BlockDriverState *bs);
 int bdrv_get_flags(BlockDriverState *bs);
 
-bool coroutine_fn bdrv_co_is_inserted(BlockDriverState *bs);
-bool co_wrapper bdrv_is_inserted(BlockDriverState *bs);
+bool coroutine_fn GRAPH_RDLOCK bdrv_co_is_inserted(BlockDriverState *bs);
+bool co_wrapper_bdrv_rdlock bdrv_is_inserted(BlockDriverState *bs);
 
 void coroutine_fn bdrv_co_lock_medium(BlockDriverState *bs, bool locked);
 void coroutine_fn bdrv_co_eject(BlockDriverState *bs, bool eject_flag);
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index 61f894bcf6..b4a82269e5 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -712,7 +712,8 @@ struct BlockDriver {
         BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 
     /* removable device specific */
-    bool coroutine_fn (*bdrv_co_is_inserted)(BlockDriverState *bs);
+    bool coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_is_inserted)(
+        BlockDriverState *bs);
     void coroutine_fn (*bdrv_co_eject)(BlockDriverState *bs, bool eject_flag);
     void coroutine_fn (*bdrv_co_lock_medium)(BlockDriverState *bs, bool locked);
 
diff --git a/include/sysemu/block-backend-io.h b/include/sysemu/block-backend-io.h
index b1196ab93c..40ab178719 100644
--- a/include/sysemu/block-backend-io.h
+++ b/include/sysemu/block-backend-io.h
@@ -55,10 +55,11 @@ BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf,
 void blk_inc_in_flight(BlockBackend *blk);
 void blk_dec_in_flight(BlockBackend *blk);
 
-bool coroutine_fn blk_co_is_inserted(BlockBackend *blk);
-bool co_wrapper_mixed blk_is_inserted(BlockBackend *blk);
+bool coroutine_fn GRAPH_RDLOCK blk_co_is_inserted(BlockBackend *blk);
+bool co_wrapper_mixed_bdrv_rdlock blk_is_inserted(BlockBackend *blk);
 
-bool blk_is_available(BlockBackend *blk);
+bool coroutine_fn GRAPH_RDLOCK blk_co_is_available(BlockBackend *blk);
+bool co_wrapper_mixed_bdrv_rdlock blk_is_available(BlockBackend *blk);
 
 void coroutine_fn blk_co_lock_medium(BlockBackend *blk, bool locked);
 void co_wrapper blk_lock_medium(BlockBackend *blk, bool locked);