[PATCH 3/6] block: assert that BlockDriver->bdrv_co_copy_range_{from/to} is always called with graph rdlock taken

[Emanuele Giuseppe Esposito <eesposit@redhat.com>]

The only non-protected caller is convert_co_copy_range(), all other
callers are BlockDriver callbacks that already take the rdlock.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block/block-backend.c            | 2 ++
 block/io.c                       | 5 +++++
 include/block/block_int-common.h | 4 ++++
 qemu-img.c                       | 4 +++-
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/block/block-backend.c b/block/block-backend.c
index 9e1c689e84..6f0dd15808 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -2631,6 +2631,8 @@ int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in,
     if (r) {
         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/block/io.c b/block/io.c
index 831f277e85..62c0b3a390 100644
--- a/block/io.c
+++ b/block/io.c
@@ -3165,6 +3165,7 @@ static int coroutine_fn bdrv_co_copy_range_internal(
 {
     BdrvTrackedRequest req;
     int ret;
+    assert_bdrv_graph_readable();
 
     /* TODO We can support BDRV_REQ_NO_FALLBACK here */
     assert(!(read_flags & BDRV_REQ_NO_FALLBACK));
@@ -3246,6 +3247,7 @@ int coroutine_fn bdrv_co_copy_range_from(BdrvChild *src, int64_t src_offset,
                                          BdrvRequestFlags write_flags)
 {
     IO_CODE();
+    assert_bdrv_graph_readable();
     trace_bdrv_co_copy_range_from(src, src_offset, dst, dst_offset, bytes,
                                   read_flags, write_flags);
     return bdrv_co_copy_range_internal(src, src_offset, dst, dst_offset,
@@ -3263,6 +3265,7 @@ int coroutine_fn bdrv_co_copy_range_to(BdrvChild *src, int64_t src_offset,
                                        BdrvRequestFlags write_flags)
 {
     IO_CODE();
+    assert_bdrv_graph_readable();
     trace_bdrv_co_copy_range_to(src, src_offset, dst, dst_offset, bytes,
                                 read_flags, write_flags);
     return bdrv_co_copy_range_internal(src, src_offset, dst, dst_offset,
@@ -3275,6 +3278,8 @@ int coroutine_fn bdrv_co_copy_range(BdrvChild *src, int64_t src_offset,
                                     BdrvRequestFlags write_flags)
 {
     IO_CODE();
+    assert_bdrv_graph_readable();
+
     return bdrv_co_copy_range_from(src, src_offset,
                                    dst, dst_offset,
                                    bytes, read_flags, write_flags);
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index 1e9bb91c98..9e441cb93b 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -574,6 +574,8 @@ struct BlockDriver {
      *
      * See the comment of bdrv_co_copy_range for the parameter and return value
      * semantics.
+     *
+     * Called with graph rdlock taken.
      */
     int coroutine_fn (*bdrv_co_copy_range_from)(BlockDriverState *bs,
                                                 BdrvChild *src,
@@ -592,6 +594,8 @@ struct BlockDriver {
      *
      * See the comment of bdrv_co_copy_range for the parameter and return value
      * semantics.
+     *
+     * Called with graph rdlock taken.
      */
     int coroutine_fn (*bdrv_co_copy_range_to)(BlockDriverState *bs,
                                               BdrvChild *src,
diff --git a/qemu-img.c b/qemu-img.c
index 33703a6d92..2086cf6eed 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -2027,7 +2027,9 @@ retry:
 
         if (s->ret == -EINPROGRESS) {
             if (copy_range) {
-                ret = convert_co_copy_range(s, sector_num, n);
+                WITH_GRAPH_RDLOCK_GUARD() {
+                    ret = convert_co_copy_range(s, sector_num, n);
+                }
                 if (ret) {
                     s->copy_range = false;
                     goto retry;
-- 
2.31.1