block: Mark read/write in block/io.c GRAPH_RDLOCK

This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_driver_*() need to hold a reader lock for the graph. It doesn't add
the annotation to public functions yet.

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: <20230203152202.49054-11-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 31 insertions, 35 deletions

diff --git a/block/io.c b/block/io.c
index 0084336..2dda1cf 100644
--- a/block/io.c
+++ b/block/io.c
@@ -160,6 +160,7 @@ void bdrv_refresh_limits(BlockDriverState *bs, Transaction *tran, Error **errp)
     bool have_limits;
 
     GLOBAL_STATE_CODE();
+    assume_graph_lock(); /* FIXME */
 
     if (tran) {
         BdrvRefreshLimitsState *s = g_new(BdrvRefreshLimitsState, 1);
@@ -961,10 +962,9 @@ static void bdrv_co_io_em_complete(void *opaque, int ret)
     aio_co_wake(co->coroutine);
 }
 
-static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
-                                           int64_t offset, int64_t bytes,
-                                           QEMUIOVector *qiov,
-                                           size_t qiov_offset, int flags)
+static int coroutine_fn GRAPH_RDLOCK
+bdrv_driver_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                   QEMUIOVector *qiov, size_t qiov_offset, int flags)
 {
     BlockDriver *drv = bs->drv;
     int64_t sector_num;
@@ -1030,11 +1030,10 @@ out:
     return ret;
 }
 
-static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs,
-                                            int64_t offset, int64_t bytes,
-                                            QEMUIOVector *qiov,
-                                            size_t qiov_offset,
-                                            BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+bdrv_driver_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
+                    QEMUIOVector *qiov, size_t qiov_offset,
+                    BdrvRequestFlags flags)
 {
     BlockDriver *drv = bs->drv;
     bool emulate_fua = false;
@@ -1043,8 +1042,6 @@ static int coroutine_fn bdrv_driver_pwritev(BlockDriverState *bs,
     QEMUIOVector local_qiov;
     int ret;
 
-    assume_graph_lock(); /* FIXME */
-
     bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort);
 
     if (!drv) {
@@ -1114,7 +1111,7 @@ emulate_flags:
     return ret;
 }
 
-static int coroutine_fn
+static int coroutine_fn GRAPH_RDLOCK
 bdrv_driver_pwritev_compressed(BlockDriverState *bs, int64_t offset,
                                int64_t bytes, QEMUIOVector *qiov,
                                size_t qiov_offset)
@@ -1149,9 +1146,9 @@ bdrv_driver_pwritev_compressed(BlockDriverState *bs, int64_t offset,
     return ret;
 }
 
-static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
-        int64_t offset, int64_t bytes, QEMUIOVector *qiov,
-        size_t qiov_offset, int flags)
+static int coroutine_fn GRAPH_RDLOCK
+bdrv_co_do_copy_on_readv(BdrvChild *child, int64_t offset, int64_t bytes,
+                         QEMUIOVector *qiov, size_t qiov_offset, int flags)
 {
     BlockDriverState *bs = child->bs;
 
@@ -1172,8 +1169,6 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
     int64_t progress = 0;
     bool skip_write;
 
-    assume_graph_lock(); /* FIXME */
-
     bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort);
 
     if (!drv) {
@@ -1315,9 +1310,10 @@ err:
  * handles copy on read, zeroing after EOF, and fragmentation of large
  * reads; any other features must be implemented by the caller.
  */
-static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
-    BdrvTrackedRequest *req, int64_t offset, int64_t bytes,
-    int64_t align, QEMUIOVector *qiov, size_t qiov_offset, int flags)
+static int coroutine_fn GRAPH_RDLOCK
+bdrv_aligned_preadv(BdrvChild *child, BdrvTrackedRequest *req,
+                    int64_t offset, int64_t bytes, int64_t align,
+                    QEMUIOVector *qiov, size_t qiov_offset, int flags)
 {
     BlockDriverState *bs = child->bs;
     int64_t total_bytes, max_bytes;
@@ -1484,10 +1480,9 @@ static bool bdrv_init_padding(BlockDriverState *bs,
     return true;
 }
 
-static coroutine_fn int bdrv_padding_rmw_read(BdrvChild *child,
-                                              BdrvTrackedRequest *req,
-                                              BdrvRequestPadding *pad,
-                                              bool zero_middle)
+static int coroutine_fn GRAPH_RDLOCK
+bdrv_padding_rmw_read(BdrvChild *child, BdrvTrackedRequest *req,
+                      BdrvRequestPadding *pad, bool zero_middle)
 {
     QEMUIOVector local_qiov;
     BlockDriverState *bs = child->bs;
@@ -1626,6 +1621,8 @@ 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)) {
@@ -1898,10 +1895,11 @@ bdrv_co_write_req_finish(BdrvChild *child, int64_t offset, int64_t bytes,
  * Forwards an already correctly aligned write request to the BlockDriver,
  * after possibly fragmenting it.
  */
-static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
-    BdrvTrackedRequest *req, int64_t offset, int64_t bytes,
-    int64_t align, QEMUIOVector *qiov, size_t qiov_offset,
-    BdrvRequestFlags flags)
+static int coroutine_fn GRAPH_RDLOCK
+bdrv_aligned_pwritev(BdrvChild *child, BdrvTrackedRequest *req,
+                     int64_t offset, int64_t bytes, int64_t align,
+                     QEMUIOVector *qiov, size_t qiov_offset,
+                     BdrvRequestFlags flags)
 {
     BlockDriverState *bs = child->bs;
     BlockDriver *drv = bs->drv;
@@ -1910,8 +1908,6 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
     int64_t bytes_remaining = bytes;
     int max_transfer;
 
-    assume_graph_lock(); /* FIXME */
-
     bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort);
 
     if (!drv) {
@@ -1987,11 +1983,9 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
     return ret;
 }
 
-static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
-                                                int64_t offset,
-                                                int64_t bytes,
-                                                BdrvRequestFlags flags,
-                                                BdrvTrackedRequest *req)
+static int coroutine_fn GRAPH_RDLOCK
+bdrv_co_do_zero_pwritev(BdrvChild *child, int64_t offset, int64_t bytes,
+                        BdrvRequestFlags flags, BdrvTrackedRequest *req)
 {
     BlockDriverState *bs = child->bs;
     QEMUIOVector local_qiov;
@@ -2079,6 +2073,8 @@ 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)) {