block: Call .bdrv_co_create(_opts) unlocked

These are functions that modify the graph, so they must be able to take
a writer lock. This is impossible if they already hold the reader lock.
If they need a reader lock for some of their operations, they should
take it internally.

Many of them go through blk_*(), which will always take the lock itself.
Direct calls of bdrv_*() need to take the reader lock. Note that while
locking for bdrv_co_*() calls is checked by TSA, this is not the case
for the mixed_coroutine_fns bdrv_*(). Holding the lock is still required
when they are called from coroutine context like here!

This effectively reverts 4ec8df0183, but adds some internal locking
instead.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230510203601.418015-2-kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/include/block/block-global-state.h b/include/block/block-global-state.h
index 2d93423d35..f347199bff 100644
--- a/include/block/block-global-state.h
+++ b/include/block/block-global-state.h
@@ -58,14 +58,14 @@ BlockDriver *bdrv_find_protocol(const char *filename,
                                 Error **errp);
 BlockDriver *bdrv_find_format(const char *format_name);
 
-int coroutine_fn GRAPH_RDLOCK
+int coroutine_fn GRAPH_UNLOCKED
 bdrv_co_create(BlockDriver *drv, const char *filename, QemuOpts *opts,
                Error **errp);
 
-int co_wrapper_bdrv_rdlock bdrv_create(BlockDriver *drv, const char *filename,
-                                       QemuOpts *opts, Error **errp);
+int co_wrapper bdrv_create(BlockDriver *drv, const char *filename,
+                           QemuOpts *opts, Error **errp);
 
-int coroutine_fn GRAPH_RDLOCK
+int coroutine_fn GRAPH_UNLOCKED
 bdrv_co_create_file(const char *filename, QemuOpts *opts, Error **errp);
 
 BlockDriverState *bdrv_new(void);