commit b9b10c35e5c8bdb800601b142c44a4bd2da5a6d2
author Kevin Wolf <kwolf@redhat.com> Fri Feb 03 16:21:50 2023 +0100
committer Kevin Wolf <kwolf@redhat.com> Thu Feb 23 19:49:17 2023 +0100
tree d0f692507ec8ea696ecea07c1aae59a839568795
parent 7b1fb72e2c1b9fbca17c13b753aee25f445cad24

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/copy-before-write.c

diff --git a/block/copy-before-write.c b/block/copy-before-write.c
index 61854be..e223e37 100644
--- a/block/copy-before-write.c
+++ b/block/copy-before-write.c
@@ -78,9 +78,9 @@
     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 @@
     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 @@
     BdrvChild *file;
     int ret;
 
+    assume_graph_lock(); /* FIXME */
+
     /* TODO: upgrade to async loop using AioTask */
     while (bytes) {
         int64_t cur_bytes;