block: Mark public read/write functions GRAPH_RDLOCK

This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_co_pread*/pwrite*() 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: <20230203152202.49054-12-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/blkdebug.c

@@ -626,7 +626,7 @@ static int rule_check(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
     return -error;
 }
 
-static int coroutine_fn
+static int coroutine_fn GRAPH_RDLOCK
 blkdebug_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
                    QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
@@ -647,7 +647,7 @@ blkdebug_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
     return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
 }
 
-static int coroutine_fn
+static int coroutine_fn GRAPH_RDLOCK
 blkdebug_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
                     QEMUIOVector *qiov, BdrvRequestFlags flags)
 {

block/blklogwrites.c

@@ -294,7 +294,7 @@ static void blk_log_writes_refresh_limits(BlockDriverState *bs, Error **errp)
     bs->bl.request_alignment = s->sectorsize;
 }
 
-static int coroutine_fn
+static int coroutine_fn GRAPH_RDLOCK
 blk_log_writes_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
                          QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
@@ -430,7 +430,7 @@ blk_log_writes_co_log(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
     return fr.file_ret;
 }
 
-static int coroutine_fn
+static int coroutine_fn GRAPH_RDLOCK
 blk_log_writes_co_do_file_pwritev(BlkLogWritesFileReq *fr)
 {
     return bdrv_co_pwritev(fr->bs->file, fr->offset, fr->bytes,
@@ -456,11 +456,10 @@ blk_log_writes_co_do_file_pdiscard(BlkLogWritesFileReq *fr)
     return bdrv_co_pdiscard(fr->bs->file, fr->offset, fr->bytes);
 }
 
-static int coroutine_fn
+static int coroutine_fn GRAPH_RDLOCK
 blk_log_writes_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
                           QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
-    assume_graph_lock(); /* FIXME */
     return blk_log_writes_co_log(bs, offset, bytes, qiov, flags,
                                  blk_log_writes_co_do_file_pwritev, 0, false);
 }

block/blkreplay.c

@@ -69,8 +69,9 @@ static void block_request_create(uint64_t reqid, BlockDriverState *bs,
     replay_block_event(req->bh, reqid);
 }
 
-static int coroutine_fn blkreplay_co_preadv(BlockDriverState *bs,
-    int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+blkreplay_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                    QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
     uint64_t reqid = blkreplay_next_id();
     int ret = bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
@@ -80,8 +81,9 @@ static int coroutine_fn blkreplay_co_preadv(BlockDriverState *bs,
     return ret;
 }
 
-static int coroutine_fn blkreplay_co_pwritev(BlockDriverState *bs,
-    int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+blkreplay_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                     QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
     uint64_t reqid = blkreplay_next_id();
     int ret = bdrv_co_pwritev(bs->file, offset, bytes, qiov, flags);

block/block-backend.c

@@ -1289,6 +1289,7 @@ blk_co_do_preadv_part(BlockBackend *blk, int64_t offset, int64_t bytes,
     IO_CODE();
 
     blk_wait_while_drained(blk);
+    GRAPH_RDLOCK_GUARD();
 
     /* Call blk_bs() only after waiting, the graph may have changed */
     bs = blk_bs(blk);
@@ -1363,6 +1364,7 @@ blk_co_do_pwritev_part(BlockBackend *blk, int64_t offset, int64_t bytes,
     IO_CODE();
 
     blk_wait_while_drained(blk);
+    GRAPH_RDLOCK_GUARD();
 
     /* Call blk_bs() only after waiting, the graph may have changed */
     bs = blk_bs(blk);

block/bochs.c

@@ -237,7 +237,7 @@ static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
     return bitmap_offset + (512 * (s->bitmap_blocks + extent_offset));
 }
 
-static int coroutine_fn
+static int coroutine_fn GRAPH_RDLOCK
 bochs_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
                 QEMUIOVector *qiov, BdrvRequestFlags flags)
 {

block/commit.c

@@ -207,8 +207,9 @@ static const BlockJobDriver commit_job_driver = {
     },
 };
 
-static int coroutine_fn bdrv_commit_top_preadv(BlockDriverState *bs,
-    int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+bdrv_commit_top_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                       QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
     return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags);
 }

block/copy-before-write.c

@@ -78,9 +78,9 @@ typedef struct BDRVCopyBeforeWriteState {
     int snapshot_error;
 } BDRVCopyBeforeWriteState;
 
-static coroutine_fn int cbw_co_preadv(
-        BlockDriverState *bs, int64_t offset, int64_t bytes,
-        QEMUIOVector *qiov, BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+cbw_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
+              QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
     return bdrv_co_preadv(bs->file, offset, bytes, qiov, flags);
 }
@@ -172,11 +172,9 @@ cbw_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int64_t bytes,
     return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
 }
 
-static coroutine_fn int cbw_co_pwritev(BlockDriverState *bs,
-                                       int64_t offset,
-                                       int64_t bytes,
-                                       QEMUIOVector *qiov,
-                                       BdrvRequestFlags flags)
+static coroutine_fn GRAPH_RDLOCK
+int cbw_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                   QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
     int ret = cbw_do_copy_before_write(bs, offset, bytes, flags);
     if (ret < 0) {
@@ -266,6 +264,8 @@ cbw_co_preadv_snapshot(BlockDriverState *bs, int64_t offset, int64_t bytes,
     BdrvChild *file;
     int ret;
 
+    assume_graph_lock(); /* FIXME */
+
     /* TODO: upgrade to async loop using AioTask */
     while (bytes) {
         int64_t cur_bytes;

block/copy-on-read.c

@@ -127,11 +127,10 @@ static int64_t coroutine_fn cor_co_getlength(BlockDriverState *bs)
 }
 
 
-static int coroutine_fn cor_co_preadv_part(BlockDriverState *bs,
-                                           int64_t offset, int64_t bytes,
-                                           QEMUIOVector *qiov,
-                                           size_t qiov_offset,
-                                           BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+cor_co_preadv_part(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                   QEMUIOVector *qiov, size_t qiov_offset,
+                   BdrvRequestFlags flags)
 {
     int64_t n;
     int local_flags;
@@ -180,12 +179,10 @@ static int coroutine_fn cor_co_preadv_part(BlockDriverState *bs,
 }
 
 
-static int coroutine_fn cor_co_pwritev_part(BlockDriverState *bs,
-                                            int64_t offset,
-                                            int64_t bytes,
-                                            QEMUIOVector *qiov,
-                                            size_t qiov_offset,
-                                            BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+cor_co_pwritev_part(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                    QEMUIOVector *qiov, size_t qiov_offset,
+                    BdrvRequestFlags flags)
 {
     return bdrv_co_pwritev_part(bs->file, offset, bytes, qiov, qiov_offset,
                                 flags);
@@ -207,10 +204,9 @@ cor_co_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes)
 }
 
 
-static int coroutine_fn cor_co_pwritev_compressed(BlockDriverState *bs,
-                                                  int64_t offset,
-                                                  int64_t bytes,
-                                                  QEMUIOVector *qiov)
+static int coroutine_fn GRAPH_RDLOCK
+cor_co_pwritev_compressed(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                          QEMUIOVector *qiov)
 {
     return bdrv_co_pwritev(bs->file, offset, bytes, qiov,
                            BDRV_REQ_WRITE_COMPRESSED);

block/crypto.c

@@ -397,7 +397,7 @@ static int block_crypto_reopen_prepare(BDRVReopenState *state,
  */
 #define BLOCK_CRYPTO_MAX_IO_SIZE (1024 * 1024)
 
-static coroutine_fn int
+static int coroutine_fn GRAPH_RDLOCK
 block_crypto_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
                        QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
@@ -459,7 +459,7 @@ block_crypto_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
 }
 
 
-static coroutine_fn int
+static int coroutine_fn GRAPH_RDLOCK
 block_crypto_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
                         QEMUIOVector *qiov, BdrvRequestFlags flags)
 {

block/filter-compress.c

@@ -61,23 +61,20 @@ static int64_t coroutine_fn compress_co_getlength(BlockDriverState *bs)
 }
 
 
-static int coroutine_fn compress_co_preadv_part(BlockDriverState *bs,
-                                                int64_t offset, int64_t bytes,
-                                                QEMUIOVector *qiov,
-                                                size_t qiov_offset,
-                                                BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+compress_co_preadv_part(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                        QEMUIOVector *qiov, size_t qiov_offset,
+                        BdrvRequestFlags flags)
 {
     return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset,
                                flags);
 }
 
 
-static int coroutine_fn compress_co_pwritev_part(BlockDriverState *bs,
-                                                 int64_t offset,
-                                                 int64_t bytes,
-                                                 QEMUIOVector *qiov,
-                                                 size_t qiov_offset,
-                                                 BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+compress_co_pwritev_part(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                         QEMUIOVector *qiov, size_t qiov_offset,
+                         BdrvRequestFlags flags)
 {
     return bdrv_co_pwritev_part(bs->file, offset, bytes, qiov, qiov_offset,
                                 flags | BDRV_REQ_WRITE_COMPRESSED);

block/io.c

@@ -971,6 +971,7 @@ bdrv_driver_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
     unsigned int nb_sectors;
     QEMUIOVector local_qiov;
     int ret;
+    assert_bdrv_graph_readable();
 
     bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort);
     assert(!(flags & ~bs->supported_read_flags));
@@ -1041,6 +1042,7 @@ bdrv_driver_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
     unsigned int nb_sectors;
     QEMUIOVector local_qiov;
     int ret;
+    assert_bdrv_graph_readable();
 
     bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort);
 
@@ -1119,6 +1121,7 @@ bdrv_driver_pwritev_compressed(BlockDriverState *bs, int64_t offset,
     BlockDriver *drv = bs->drv;
     QEMUIOVector local_qiov;
     int ret;
+    assert_bdrv_graph_readable();
 
     bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort);
 
@@ -1621,8 +1624,6 @@ int coroutine_fn bdrv_co_preadv_part(BdrvChild *child,
     int ret;
     IO_CODE();
 
-    assume_graph_lock(); /* FIXME */
-
     trace_bdrv_co_preadv_part(bs, offset, bytes, flags);
 
     if (!bdrv_co_is_inserted(bs)) {
@@ -2073,8 +2074,6 @@ int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child,
     bool padded = false;
     IO_CODE();
 
-    assume_graph_lock(); /* FIXME */
-
     trace_bdrv_co_pwritev_part(child->bs, offset, bytes, flags);
 
     if (!bdrv_co_is_inserted(bs)) {

block/mirror.c

@@ -390,8 +390,10 @@ static void coroutine_fn mirror_co_read(void *opaque)
     op->is_in_flight = true;
     trace_mirror_one_iteration(s, op->offset, op->bytes);
 
-    ret = bdrv_co_preadv(s->mirror_top_bs->backing, op->offset, op->bytes,
-                         &op->qiov, 0);
+    WITH_GRAPH_RDLOCK_GUARD() {
+        ret = bdrv_co_preadv(s->mirror_top_bs->backing, op->offset, op->bytes,
+                             &op->qiov, 0);
+    }
     mirror_read_complete(op, ret);
 }
 
@@ -1437,8 +1439,9 @@ static void coroutine_fn active_write_settle(MirrorOp *op)
     g_free(op);
 }
 
-static int coroutine_fn bdrv_mirror_top_preadv(BlockDriverState *bs,
-    int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+bdrv_mirror_top_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                       QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
     return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags);
 }
@@ -1495,8 +1498,9 @@ out:
     return ret;
 }
 
-static int coroutine_fn bdrv_mirror_top_pwritev(BlockDriverState *bs,
-    int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+bdrv_mirror_top_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                        QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
     MirrorBDSOpaque *s = bs->opaque;
     QEMUIOVector bounce_qiov;
@@ -1504,8 +1508,6 @@ static int coroutine_fn bdrv_mirror_top_pwritev(BlockDriverState *bs,
     int ret = 0;
     bool copy_to_target = false;
 
-    assume_graph_lock(); /* FIXME */
-
     if (s->job) {
         copy_to_target = s->job->ret >= 0 &&
                          !job_is_cancelled(&s->job->common.job) &&

block/parallels.c

@@ -261,7 +261,8 @@ allocate_clusters(BlockDriverState *bs, int64_t sector_num,
 }
 
 
-static coroutine_fn int parallels_co_flush_to_os(BlockDriverState *bs)
+static int coroutine_fn GRAPH_RDLOCK
+parallels_co_flush_to_os(BlockDriverState *bs)
 {
     BDRVParallelsState *s = bs->opaque;
     unsigned long size = DIV_ROUND_UP(s->header_size, s->bat_dirty_block);
@@ -363,8 +364,9 @@ parallels_co_writev(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
     return ret;
 }
 
-static coroutine_fn int parallels_co_readv(BlockDriverState *bs,
-        int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
+static int coroutine_fn GRAPH_RDLOCK
+parallels_co_readv(BlockDriverState *bs, int64_t sector_num, int nb_sectors,
+                   QEMUIOVector *qiov)
 {
     BDRVParallelsState *s = bs->opaque;
     uint64_t bytes_done = 0;

block/preallocate.c

@@ -226,9 +226,10 @@ static void preallocate_reopen_abort(BDRVReopenState *state)
     state->opaque = NULL;
 }
 
-static coroutine_fn int preallocate_co_preadv_part(
-        BlockDriverState *bs, int64_t offset, int64_t bytes,
-        QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+preallocate_co_preadv_part(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                           QEMUIOVector *qiov, size_t qiov_offset,
+                           BdrvRequestFlags flags)
 {
     return bdrv_co_preadv_part(bs->file, offset, bytes, qiov, qiov_offset,
                                flags);
@@ -359,14 +360,11 @@ preallocate_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
     return bdrv_co_pwrite_zeroes(bs->file, offset, bytes, flags);
 }
 
-static coroutine_fn int preallocate_co_pwritev_part(BlockDriverState *bs,
-                                                    int64_t offset,
-                                                    int64_t bytes,
-                                                    QEMUIOVector *qiov,
-                                                    size_t qiov_offset,
-                                                    BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+preallocate_co_pwritev_part(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                            QEMUIOVector *qiov, size_t qiov_offset,
+                            BdrvRequestFlags flags)
 {
-    assume_graph_lock(); /* FIXME */
     handle_write(bs, offset, bytes, false);
 
     return bdrv_co_pwritev_part(bs->file, offset, bytes, qiov, qiov_offset,

block/qcow.c

@@ -92,8 +92,8 @@ typedef struct BDRVQcowState {
 
 static QemuOptsList qcow_create_opts;
 
-static int coroutine_fn decompress_cluster(BlockDriverState *bs,
-                                           uint64_t cluster_offset);
+static int coroutine_fn GRAPH_RDLOCK
+decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
 
 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
 {
@@ -584,8 +584,8 @@ static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
     return 0;
 }
 
-static int coroutine_fn decompress_cluster(BlockDriverState *bs,
-                                           uint64_t cluster_offset)
+static int coroutine_fn GRAPH_RDLOCK
+decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
 {
     BDRVQcowState *s = bs->opaque;
     int ret, csize;

block/qcow2-cluster.c

@@ -534,10 +534,9 @@ do_perform_cow_read(BlockDriverState *bs, uint64_t src_cluster_offset,
     return 0;
 }
 
-static int coroutine_fn do_perform_cow_write(BlockDriverState *bs,
-                                             uint64_t cluster_offset,
-                                             unsigned offset_in_cluster,
-                                             QEMUIOVector *qiov)
+static int coroutine_fn GRAPH_RDLOCK
+do_perform_cow_write(BlockDriverState *bs, uint64_t cluster_offset,
+                     unsigned offset_in_cluster, QEMUIOVector *qiov)
 {
     BDRVQcow2State *s = bs->opaque;
     int ret;

block/qcow2.c

@@ -601,9 +601,9 @@ static void qcow2_add_check_result(BdrvCheckResult *out,
     }
 }
 
-static int coroutine_fn qcow2_co_check_locked(BlockDriverState *bs,
-                                              BdrvCheckResult *result,
-                                              BdrvCheckMode fix)
+static int coroutine_fn GRAPH_RDLOCK
+qcow2_co_check_locked(BlockDriverState *bs, BdrvCheckResult *result,
+                      BdrvCheckMode fix)
 {
     BdrvCheckResult snapshot_res = {};
     BdrvCheckResult refcount_res = {};
@@ -640,9 +640,9 @@ static int coroutine_fn qcow2_co_check_locked(BlockDriverState *bs,
     return ret;
 }
 
-static int coroutine_fn qcow2_co_check(BlockDriverState *bs,
-                                       BdrvCheckResult *result,
-                                       BdrvCheckMode fix)
+static int coroutine_fn GRAPH_RDLOCK
+qcow2_co_check(BlockDriverState *bs, BdrvCheckResult *result,
+               BdrvCheckMode fix)
 {
     BDRVQcow2State *s = bs->opaque;
     int ret;
@@ -1294,9 +1294,9 @@ static int validate_compression_type(BDRVQcow2State *s, Error **errp)
 }
 
 /* Called with s->lock held.  */
-static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
-                                      int flags, bool open_data_file,
-                                      Error **errp)
+static int coroutine_fn GRAPH_RDLOCK
+qcow2_do_open(BlockDriverState *bs, QDict *options, int flags,
+              bool open_data_file, Error **errp)
 {
     ERRP_GUARD();
     BDRVQcow2State *s = bs->opaque;
@@ -1890,6 +1890,8 @@ static void coroutine_fn qcow2_open_entry(void *opaque)
     QCow2OpenCo *qoc = opaque;
     BDRVQcow2State *s = qoc->bs->opaque;
 
+    assume_graph_lock(); /* FIXME */
+
     qemu_co_mutex_lock(&s->lock);
     qoc->ret = qcow2_do_open(qoc->bs, qoc->options, qoc->flags, true,
                              qoc->errp);
@@ -2169,7 +2171,7 @@ out:
     return ret;
 }
 
-static coroutine_fn int
+static int coroutine_fn GRAPH_RDLOCK
 qcow2_co_preadv_encrypted(BlockDriverState *bs,
                            uint64_t host_offset,
                            uint64_t offset,
@@ -2270,12 +2272,10 @@ static coroutine_fn int qcow2_add_task(BlockDriverState *bs,
     return 0;
 }
 
-static coroutine_fn int qcow2_co_preadv_task(BlockDriverState *bs,
-                                             QCow2SubclusterType subc_type,
-                                             uint64_t host_offset,
-                                             uint64_t offset, uint64_t bytes,
-                                             QEMUIOVector *qiov,
-                                             size_t qiov_offset)
+static int coroutine_fn GRAPH_RDLOCK
+qcow2_co_preadv_task(BlockDriverState *bs, QCow2SubclusterType subc_type,
+                     uint64_t host_offset, uint64_t offset, uint64_t bytes,
+                     QEMUIOVector *qiov, size_t qiov_offset)
 {
     BDRVQcow2State *s = bs->opaque;
 
@@ -2314,7 +2314,11 @@ static coroutine_fn int qcow2_co_preadv_task(BlockDriverState *bs,
     g_assert_not_reached();
 }
 
-static coroutine_fn int qcow2_co_preadv_task_entry(AioTask *task)
+/*
+ * This function can count as GRAPH_RDLOCK because qcow2_co_preadv_part() holds
+ * the graph lock and keeps it until this coroutine has terminated.
+ */
+static int coroutine_fn GRAPH_RDLOCK qcow2_co_preadv_task_entry(AioTask *task)
 {
     Qcow2AioTask *t = container_of(task, Qcow2AioTask, task);
 
@@ -2325,11 +2329,10 @@ static coroutine_fn int qcow2_co_preadv_task_entry(AioTask *task)
                                 t->qiov, t->qiov_offset);
 }
 
-static coroutine_fn int qcow2_co_preadv_part(BlockDriverState *bs,
-                                             int64_t offset, int64_t bytes,
-                                             QEMUIOVector *qiov,
-                                             size_t qiov_offset,
-                                             BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+qcow2_co_preadv_part(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                     QEMUIOVector *qiov, size_t qiov_offset,
+                     BdrvRequestFlags flags)
 {
     BDRVQcow2State *s = bs->opaque;
     int ret = 0;
@@ -2774,8 +2777,8 @@ static void qcow2_close(BlockDriverState *bs)
     qcow2_do_close(bs, true);
 }
 
-static void coroutine_fn qcow2_co_invalidate_cache(BlockDriverState *bs,
-                                                   Error **errp)
+static void coroutine_fn GRAPH_RDLOCK
+qcow2_co_invalidate_cache(BlockDriverState *bs, Error **errp)
 {
     ERRP_GUARD();
     BDRVQcow2State *s = bs->opaque;
@@ -4737,7 +4740,7 @@ qcow2_co_pwritev_compressed_part(BlockDriverState *bs,
     return ret;
 }
 
-static int coroutine_fn
+static int coroutine_fn GRAPH_RDLOCK
 qcow2_co_preadv_compressed(BlockDriverState *bs,
                            uint64_t l2_entry,
                            uint64_t offset,

block/qcow2.h

@@ -846,7 +846,7 @@ int qcow2_validate_table(BlockDriverState *bs, uint64_t offset,
                          Error **errp);
 
 /* qcow2-refcount.c functions */
-int coroutine_fn qcow2_refcount_init(BlockDriverState *bs);
+int coroutine_fn GRAPH_RDLOCK qcow2_refcount_init(BlockDriverState *bs);
 void qcow2_refcount_close(BlockDriverState *bs);
 
 int qcow2_get_refcount(BlockDriverState *bs, int64_t cluster_index,
@@ -954,9 +954,10 @@ void qcow2_free_snapshots(BlockDriverState *bs);
 int qcow2_read_snapshots(BlockDriverState *bs, Error **errp);
 int qcow2_write_snapshots(BlockDriverState *bs);
 
-int coroutine_fn qcow2_check_read_snapshot_table(BlockDriverState *bs,
-                                                 BdrvCheckResult *result,
-                                                 BdrvCheckMode fix);
+int coroutine_fn GRAPH_RDLOCK
+qcow2_check_read_snapshot_table(BlockDriverState *bs, BdrvCheckResult *result,
+                                BdrvCheckMode fix);
+
 int coroutine_fn qcow2_check_fix_snapshot_table(BlockDriverState *bs,
                                                 BdrvCheckResult *result,
                                                 BdrvCheckMode fix);

block/qed-table.c

@@ -21,8 +21,8 @@
 #include "qemu/memalign.h"
 
 /* Called with table_lock held.  */
-static int coroutine_fn qed_read_table(BDRVQEDState *s, uint64_t offset,
-                                       QEDTable *table)
+static int coroutine_fn GRAPH_RDLOCK
+qed_read_table(BDRVQEDState *s, uint64_t offset, QEDTable *table)
 {
     unsigned int bytes = s->header.cluster_size * s->header.table_size;
 

block/qed.c

@@ -100,7 +100,7 @@ int qed_write_header_sync(BDRVQEDState *s)
  *
  * No new allocating reqs can start while this function runs.
  */
-static int coroutine_fn qed_write_header(BDRVQEDState *s)
+static int coroutine_fn GRAPH_RDLOCK qed_write_header(BDRVQEDState *s)
 {
     /* We must write full sectors for O_DIRECT but cannot necessarily generate
      * the data following the header if an unrecognized compat feature is
@@ -826,11 +826,10 @@ fail:
     return ret;
 }
 
-static int coroutine_fn bdrv_qed_co_block_status(BlockDriverState *bs,
-                                                 bool want_zero,
-                                                 int64_t pos, int64_t bytes,
-                                                 int64_t *pnum, int64_t *map,
-                                                 BlockDriverState **file)
+static int coroutine_fn GRAPH_RDLOCK
+bdrv_qed_co_block_status(BlockDriverState *bs, bool want_zero, int64_t pos,
+                         int64_t bytes, int64_t *pnum, int64_t *map,
+                         BlockDriverState **file)
 {
     BDRVQEDState *s = bs->opaque;
     size_t len = MIN(bytes, SIZE_MAX);
@@ -883,8 +882,8 @@ static BDRVQEDState *acb_to_s(QEDAIOCB *acb)
  * This function reads qiov->size bytes starting at pos from the backing file.
  * If there is no backing file then zeroes are read.
  */
-static int coroutine_fn qed_read_backing_file(BDRVQEDState *s, uint64_t pos,
-                                              QEMUIOVector *qiov)
+static int coroutine_fn GRAPH_RDLOCK
+qed_read_backing_file(BDRVQEDState *s, uint64_t pos, QEMUIOVector *qiov)
 {
     if (s->bs->backing) {
         BLKDBG_EVENT(s->bs->file, BLKDBG_READ_BACKING_AIO);
@@ -902,9 +901,9 @@ static int coroutine_fn qed_read_backing_file(BDRVQEDState *s, uint64_t pos,
  * @len:        Number of bytes
  * @offset:     Byte offset in image file
  */
-static int coroutine_fn qed_copy_from_backing_file(BDRVQEDState *s,
-                                                   uint64_t pos, uint64_t len,
-                                                   uint64_t offset)
+static int coroutine_fn GRAPH_RDLOCK
+qed_copy_from_backing_file(BDRVQEDState *s, uint64_t pos, uint64_t len,
+                           uint64_t offset)
 {
     QEMUIOVector qiov;
     int ret;
@@ -1066,7 +1065,7 @@ qed_aio_write_l2_update(QEDAIOCB *acb, uint64_t offset)
  *
  * Called with table_lock *not* held.
  */
-static int coroutine_fn qed_aio_write_main(QEDAIOCB *acb)
+static int coroutine_fn GRAPH_RDLOCK qed_aio_write_main(QEDAIOCB *acb)
 {
     BDRVQEDState *s = acb_to_s(acb);
     uint64_t offset = acb->cur_cluster +
@@ -1226,8 +1225,8 @@ qed_aio_write_alloc(QEDAIOCB *acb, size_t len)
  *
  * Called with table_lock held.
  */
-static int coroutine_fn qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset,
-                                              size_t len)
+static int coroutine_fn GRAPH_RDLOCK
+qed_aio_write_inplace(QEDAIOCB *acb, uint64_t offset, size_t len)
 {
     BDRVQEDState *s = acb_to_s(acb);
     int r;
@@ -1302,8 +1301,8 @@ qed_aio_write_data(void *opaque, int ret, uint64_t offset, size_t len)
  *
  * Called with table_lock held.
  */
-static int coroutine_fn qed_aio_read_data(void *opaque, int ret,
-                                          uint64_t offset, size_t len)
+static int coroutine_fn GRAPH_RDLOCK
+qed_aio_read_data(void *opaque, int ret, uint64_t offset, size_t len)
 {
     QEDAIOCB *acb = opaque;
     BDRVQEDState *s = acb_to_s(acb);