block: Mark bdrv_refresh_filename() and callers GRAPH_RDLOCK

This adds GRAPH_RDLOCK annotations to declare that callers of
bdrv_refresh_filename() need to hold a reader lock for the graph
because it accesses the children list of a node.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20230929145157.45443-11-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

6 files changed, 49 insertions, 26 deletions

diff --git a/block/nfs.c b/block/nfs.c
index c24df49..f737e19 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -843,7 +843,7 @@ static void nfs_refresh_filename(BlockDriverState *bs)
     }
 }
 
-static char *nfs_dirname(BlockDriverState *bs, Error **errp)
+static char * GRAPH_RDLOCK nfs_dirname(BlockDriverState *bs, Error **errp)
 {
     NFSClient *client = bs->opaque;
 
diff --git a/block/qapi.c b/block/qapi.c
index 1cbb093..82a30b3 100644
--- a/block/qapi.c
+++ b/block/qapi.c
@@ -225,9 +225,8 @@ int bdrv_query_snapshot_info_list(BlockDriverState *bs,
  * Helper function for other query info functions.  Store information about @bs
  * in @info, setting @errp on error.
  */
-static void bdrv_do_query_node_info(BlockDriverState *bs,
-                                    BlockNodeInfo *info,
-                                    Error **errp)
+static void GRAPH_RDLOCK
+bdrv_do_query_node_info(BlockDriverState *bs, BlockNodeInfo *info, Error **errp)
 {
     int64_t size;
     const char *backing_filename;
@@ -423,8 +422,8 @@ fail:
 }
 
 /* @p_info will be set only on success. */
-static void bdrv_query_info(BlockBackend *blk, BlockInfo **p_info,
-                            Error **errp)
+static void GRAPH_RDLOCK
+bdrv_query_info(BlockBackend *blk, BlockInfo **p_info, Error **errp)
 {
     BlockInfo *info = g_malloc0(sizeof(*info));
     BlockDriverState *bs = blk_bs(blk);
@@ -672,6 +671,8 @@ BlockInfoList *qmp_query_block(Error **errp)
     BlockBackend *blk;
     Error *local_err = NULL;
 
+    GRAPH_RDLOCK_GUARD_MAINLOOP();
+
     for (blk = blk_all_next(NULL); blk; blk = blk_all_next(blk)) {
         BlockInfoList *info;
 
diff --git a/block/raw-format.c b/block/raw-format.c
index a8bdee5..8ff03ad 100644
--- a/block/raw-format.c
+++ b/block/raw-format.c
@@ -505,7 +505,9 @@ static int raw_open(BlockDriverState *bs, QDict *options, int flags,
                                    BDRV_REQ_ZERO_WRITE;
 
     if (bs->probed && !bdrv_is_read_only(bs)) {
+        bdrv_graph_rdlock_main_loop();
         bdrv_refresh_filename(bs->file->bs);
+        bdrv_graph_rdunlock_main_loop();
         fprintf(stderr,
                 "WARNING: Image format was not specified for '%s' and probing "
                 "guessed raw.\n"
diff --git a/block/vhdx.c b/block/vhdx.c
index a67edcc..73cb214 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -1001,11 +1001,15 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
     uint64_t signature;
     Error *local_err = NULL;
 
+    GLOBAL_STATE_CODE();
+
     ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
     if (ret < 0) {
         return ret;
     }
 
+    GRAPH_RDLOCK_GUARD_MAINLOOP();
+
     s->bat = NULL;
     s->first_visible_write = true;
 
diff --git a/block/vhdx.h b/block/vhdx.h
index 455a627..85594a5 100644
--- a/block/vhdx.h
+++ b/block/vhdx.h
@@ -410,8 +410,9 @@ uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size,
 
 bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset);
 
-int vhdx_parse_log(BlockDriverState *bs, BDRVVHDXState *s, bool *flushed,
-                   Error **errp);
+int GRAPH_RDLOCK
+vhdx_parse_log(BlockDriverState *bs, BDRVVHDXState *s, bool *flushed,
+               Error **errp);
 
 int coroutine_fn GRAPH_RDLOCK
 vhdx_log_write_and_flush(BlockDriverState *bs, BDRVVHDXState *s,
diff --git a/block/vmdk.c b/block/vmdk.c
index e90649c..e50965b 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -578,8 +578,8 @@ static int vmdk_add_extent(BlockDriverState *bs,
     return 0;
 }
 
-static int vmdk_init_tables(BlockDriverState *bs, VmdkExtent *extent,
-                            Error **errp)
+static int GRAPH_RDLOCK
+vmdk_init_tables(BlockDriverState *bs, VmdkExtent *extent, Error **errp)
 {
     int ret;
     size_t l1_size;
@@ -641,9 +641,9 @@ static int vmdk_init_tables(BlockDriverState *bs, VmdkExtent *extent,
     return ret;
 }
 
-static int vmdk_open_vmfs_sparse(BlockDriverState *bs,
-                                 BdrvChild *file,
-                                 int flags, Error **errp)
+static int GRAPH_RDLOCK
+vmdk_open_vmfs_sparse(BlockDriverState *bs, BdrvChild *file, int flags,
+                      Error **errp)
 {
     int ret;
     uint32_t magic;
@@ -797,9 +797,9 @@ static int check_se_sparse_volatile_header(VMDKSESparseVolatileHeader *header,
     return 0;
 }
 
-static int vmdk_open_se_sparse(BlockDriverState *bs,
-                               BdrvChild *file,
-                               int flags, Error **errp)
+static int GRAPH_RDLOCK
+vmdk_open_se_sparse(BlockDriverState *bs, BdrvChild *file, int flags,
+                    Error **errp)
 {
     int ret;
     VMDKSESparseConstHeader const_header;
@@ -913,9 +913,9 @@ static char *vmdk_read_desc(BdrvChild *file, uint64_t desc_offset, Error **errp)
     return buf;
 }
 
-static int vmdk_open_vmdk4(BlockDriverState *bs,
-                           BdrvChild *file,
-                           int flags, QDict *options, Error **errp)
+static int GRAPH_RDLOCK
+vmdk_open_vmdk4(BlockDriverState *bs, BdrvChild *file, int flags,
+                QDict *options, Error **errp)
 {
     int ret;
     uint32_t magic;
@@ -1095,8 +1095,9 @@ static int vmdk_parse_description(const char *desc, const char *opt_name,
 }
 
 /* Open an extent file and append to bs array */
-static int vmdk_open_sparse(BlockDriverState *bs, BdrvChild *file, int flags,
-                            char *buf, QDict *options, Error **errp)
+static int GRAPH_RDLOCK
+vmdk_open_sparse(BlockDriverState *bs, BdrvChild *file, int flags,
+                 char *buf, QDict *options, Error **errp)
 {
     uint32_t magic;
 
@@ -1123,8 +1124,9 @@ static const char *next_line(const char *s)
     return s;
 }
 
-static int vmdk_parse_extents(const char *desc, BlockDriverState *bs,
-                              QDict *options, Error **errp)
+static int GRAPH_RDLOCK
+vmdk_parse_extents(const char *desc, BlockDriverState *bs, QDict *options,
+                   Error **errp)
 {
     int ret;
     int matches;
@@ -1143,6 +1145,8 @@ static int vmdk_parse_extents(const char *desc, BlockDriverState *bs,
     char extent_opt_prefix[32];
     Error *local_err = NULL;
 
+    GLOBAL_STATE_CODE();
+
     for (p = desc; *p; p = next_line(p)) {
         /* parse extent line in one of below formats:
          *
@@ -1223,9 +1227,11 @@ static int vmdk_parse_extents(const char *desc, BlockDriverState *bs,
             ret = vmdk_add_extent(bs, extent_file, true, sectors,
                             0, 0, 0, 0, 0, &extent, errp);
             if (ret < 0) {
+                bdrv_graph_rdunlock_main_loop();
                 bdrv_graph_wrlock(NULL);
                 bdrv_unref_child(bs, extent_file);
                 bdrv_graph_wrunlock();
+                bdrv_graph_rdlock_main_loop();
                 goto out;
             }
             extent->flat_start_offset = flat_offset << 9;
@@ -1240,26 +1246,32 @@ static int vmdk_parse_extents(const char *desc, BlockDriverState *bs,
             }
             g_free(buf);
             if (ret) {
+                bdrv_graph_rdunlock_main_loop();
                 bdrv_graph_wrlock(NULL);
                 bdrv_unref_child(bs, extent_file);
                 bdrv_graph_wrunlock();
+                bdrv_graph_rdlock_main_loop();
                 goto out;
             }
             extent = &s->extents[s->num_extents - 1];
         } else if (!strcmp(type, "SESPARSE")) {
             ret = vmdk_open_se_sparse(bs, extent_file, bs->open_flags, errp);
             if (ret) {
+                bdrv_graph_rdunlock_main_loop();
                 bdrv_graph_wrlock(NULL);
                 bdrv_unref_child(bs, extent_file);
                 bdrv_graph_wrunlock();
+                bdrv_graph_rdlock_main_loop();
                 goto out;
             }
             extent = &s->extents[s->num_extents - 1];
         } else {
             error_setg(errp, "Unsupported extent type '%s'", type);
+            bdrv_graph_rdunlock_main_loop();
             bdrv_graph_wrlock(NULL);
             bdrv_unref_child(bs, extent_file);
             bdrv_graph_wrunlock();
+            bdrv_graph_rdlock_main_loop();
             ret = -ENOTSUP;
             goto out;
         }
@@ -1283,8 +1295,9 @@ out:
     return ret;
 }
 
-static int vmdk_open_desc_file(BlockDriverState *bs, int flags, char *buf,
-                               QDict *options, Error **errp)
+static int GRAPH_RDLOCK
+vmdk_open_desc_file(BlockDriverState *bs, int flags, char *buf, QDict *options,
+                    Error **errp)
 {
     int ret;
     char ct[128];
@@ -2900,7 +2913,7 @@ static int vmdk_has_zero_init(BlockDriverState *bs)
     return 1;
 }
 
-static VmdkExtentInfo *vmdk_get_extent_info(VmdkExtent *extent)
+static VmdkExtentInfo * GRAPH_RDLOCK vmdk_get_extent_info(VmdkExtent *extent)
 {
     VmdkExtentInfo *info = g_new0(VmdkExtentInfo, 1);
 
@@ -2985,6 +2998,8 @@ static ImageInfoSpecific *vmdk_get_specific_info(BlockDriverState *bs,
     ImageInfoSpecific *spec_info = g_new0(ImageInfoSpecific, 1);
     VmdkExtentInfoList **tail;
 
+    assume_graph_lock(); /* FIXME */
+
     *spec_info = (ImageInfoSpecific){
         .type = IMAGE_INFO_SPECIFIC_KIND_VMDK,
         .u = {