block: Mark bdrv_has_zero_init() and callers GRAPH_RDLOCK

This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_has_zero_init() need to hold a reader lock for the graph because
it calls bdrv_filter_bs(), which accesses bs->file/backing.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231027155333.420094-3-kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

6 files changed, 15 insertions, 9 deletions

diff --git a/block/qcow2.c b/block/qcow2.c
index aa01d9e7b5..a1443a31aa 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -5302,7 +5302,8 @@ static ImageInfoSpecific *qcow2_get_specific_info(BlockDriverState *bs,
     return spec_info;
 }
 
-static int coroutine_mixed_fn qcow2_has_zero_init(BlockDriverState *bs)
+static int coroutine_mixed_fn GRAPH_RDLOCK
+qcow2_has_zero_init(BlockDriverState *bs)
 {
     BDRVQcow2State *s = bs->opaque;
     bool preallocated;
diff --git a/block/raw-format.c b/block/raw-format.c
index 3fb77b0097..8ca74c1cf3 100644
--- a/block/raw-format.c
+++ b/block/raw-format.c
@@ -452,7 +452,7 @@ raw_co_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
     return bdrv_co_ioctl(bs->file->bs, req, buf);
 }
 
-static int raw_has_zero_init(BlockDriverState *bs)
+static int GRAPH_RDLOCK raw_has_zero_init(BlockDriverState *bs)
 {
     return bdrv_has_zero_init(bs->file->bs);
 }
diff --git a/block/vdi.c b/block/vdi.c
index 7cfd12b50d..8e144ce523 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -990,7 +990,7 @@ static void vdi_close(BlockDriverState *bs)
     migrate_del_blocker(&s->migration_blocker);
 }
 
-static int vdi_has_zero_init(BlockDriverState *bs)
+static int GRAPH_RDLOCK vdi_has_zero_init(BlockDriverState *bs)
 {
     BDRVVdiState *s = bs->opaque;
 
diff --git a/block/vhdx.c b/block/vhdx.c
index a9d08742f9..e136ba1ae1 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -1695,7 +1695,7 @@ exit:
  *  Fixed images: default state of the BAT is fully populated, with
  *                file offsets and state PAYLOAD_BLOCK_FULLY_PRESENT.
  */
-static int coroutine_fn
+static int coroutine_fn GRAPH_UNLOCKED
 vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
                 uint64_t image_size, VHDXImageType type,
                 bool use_zero_blocks, uint64_t file_offset,
@@ -1708,6 +1708,7 @@ vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
     uint64_t unused;
     int block_state;
     VHDXSectorInfo sinfo;
+    bool has_zero_init;
 
     assert(s->bat == NULL);
 
@@ -1737,9 +1738,13 @@ vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
         goto exit;
     }
 
+    bdrv_graph_co_rdlock();
+    has_zero_init = bdrv_has_zero_init(blk_bs(blk));
+    bdrv_graph_co_rdunlock();
+
     if (type == VHDX_TYPE_FIXED ||
                 use_zero_blocks ||
-                bdrv_has_zero_init(blk_bs(blk)) == 0) {
+                has_zero_init == 0) {
         /* for a fixed file, the default BAT entry is not zero */
         s->bat = g_try_malloc0(length);
         if (length && s->bat == NULL) {
@@ -1782,7 +1787,7 @@ exit:
  * to create the BAT itself, we will also cause the BAT to be
  * created.
  */
-static int coroutine_fn
+static int coroutine_fn GRAPH_UNLOCKED
 vhdx_create_new_region_table(BlockBackend *blk, uint64_t image_size,
                              uint32_t block_size, uint32_t sector_size,
                              uint32_t log_size, bool use_zero_blocks,
@@ -2173,7 +2178,7 @@ static int coroutine_fn vhdx_co_check(BlockDriverState *bs,
     return 0;
 }
 
-static int vhdx_has_zero_init(BlockDriverState *bs)
+static int GRAPH_RDLOCK vhdx_has_zero_init(BlockDriverState *bs)
 {
     BDRVVHDXState *s = bs->opaque;
     int state;
diff --git a/block/vmdk.c b/block/vmdk.c
index 85864b8045..91ed7a8d93 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -2894,7 +2894,7 @@ vmdk_co_get_allocated_file_size(BlockDriverState *bs)
     return ret;
 }
 
-static int vmdk_has_zero_init(BlockDriverState *bs)
+static int GRAPH_RDLOCK vmdk_has_zero_init(BlockDriverState *bs)
 {
     int i;
     BDRVVmdkState *s = bs->opaque;
diff --git a/block/vpc.c b/block/vpc.c
index aa1a48ae0e..483775103c 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -1170,7 +1170,7 @@ fail:
 }
 
 
-static int vpc_has_zero_init(BlockDriverState *bs)
+static int GRAPH_RDLOCK vpc_has_zero_init(BlockDriverState *bs)
 {
     BDRVVPCState *s = bs->opaque;