block: Mark bdrv_parent_perms_conflict() and callers GRAPH_RDLOCK

The function reads the parents list, so it needs to hold the graph lock.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20230911094620.45040-14-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

4 files changed, 34 insertions, 8 deletions

diff --git a/block/block-backend.c b/block/block-backend.c
index 4009ed5fed..8d0282a5d9 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -121,6 +121,10 @@ static QTAILQ_HEAD(, BlockBackend) block_backends =
 static QTAILQ_HEAD(, BlockBackend) monitor_block_backends =
     QTAILQ_HEAD_INITIALIZER(monitor_block_backends);
 
+static int coroutine_mixed_fn GRAPH_RDLOCK
+blk_set_perm_locked(BlockBackend *blk, uint64_t perm, uint64_t shared_perm,
+                    Error **errp);
+
 static void blk_root_inherit_options(BdrvChildRole role, bool parent_is_format,
                                      int *child_flags, QDict *child_options,
                                      int parent_flags, QDict *parent_options)
@@ -186,7 +190,7 @@ static void blk_vm_state_changed(void *opaque, bool running, RunState state)
  *
  * If an error is returned, the VM cannot be allowed to be resumed.
  */
-static void blk_root_activate(BdrvChild *child, Error **errp)
+static void GRAPH_RDLOCK blk_root_activate(BdrvChild *child, Error **errp)
 {
     BlockBackend *blk = child->opaque;
     Error *local_err = NULL;
@@ -207,7 +211,7 @@ static void blk_root_activate(BdrvChild *child, Error **errp)
      */
     saved_shared_perm = blk->shared_perm;
 
-    blk_set_perm(blk, blk->perm, BLK_PERM_ALL, &local_err);
+    blk_set_perm_locked(blk, blk->perm, BLK_PERM_ALL, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         blk->disable_perm = true;
@@ -226,7 +230,7 @@ static void blk_root_activate(BdrvChild *child, Error **errp)
         return;
     }
 
-    blk_set_perm(blk, blk->perm, blk->shared_perm, &local_err);
+    blk_set_perm_locked(blk, blk->perm, blk->shared_perm, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         blk->disable_perm = true;
@@ -259,7 +263,7 @@ static bool blk_can_inactivate(BlockBackend *blk)
     return blk->force_allow_inactivate;
 }
 
-static int blk_root_inactivate(BdrvChild *child)
+static int GRAPH_RDLOCK blk_root_inactivate(BdrvChild *child)
 {
     BlockBackend *blk = child->opaque;
 
@@ -953,8 +957,9 @@ int blk_replace_bs(BlockBackend *blk, BlockDriverState *new_bs, Error **errp)
 /*
  * Sets the permission bitmasks that the user of the BlockBackend needs.
  */
-int blk_set_perm(BlockBackend *blk, uint64_t perm, uint64_t shared_perm,
-                 Error **errp)
+static int coroutine_mixed_fn GRAPH_RDLOCK
+blk_set_perm_locked(BlockBackend *blk, uint64_t perm, uint64_t shared_perm,
+                    Error **errp)
 {
     int ret;
     GLOBAL_STATE_CODE();
@@ -972,6 +977,15 @@ int blk_set_perm(BlockBackend *blk, uint64_t perm, uint64_t shared_perm,
     return 0;
 }
 
+int blk_set_perm(BlockBackend *blk, uint64_t perm, uint64_t shared_perm,
+                 Error **errp)
+{
+    GLOBAL_STATE_CODE();
+    GRAPH_RDLOCK_GUARD_MAINLOOP();
+
+    return blk_set_perm_locked(blk, perm, shared_perm, errp);
+}
+
 void blk_get_perm(BlockBackend *blk, uint64_t *perm, uint64_t *shared_perm)
 {
     GLOBAL_STATE_CODE();
diff --git a/block/crypto.c b/block/crypto.c
index 6ee8d46d30..c9c9a39fa3 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -777,7 +777,7 @@ block_crypto_get_specific_info_luks(BlockDriverState *bs, Error **errp)
     return spec_info;
 }
 
-static int
+static int GRAPH_RDLOCK
 block_crypto_amend_prepare(BlockDriverState *bs, Error **errp)
 {
     BlockCrypto *crypto = bs->opaque;
@@ -793,7 +793,7 @@ block_crypto_amend_prepare(BlockDriverState *bs, Error **errp)
     return ret;
 }
 
-static void
+static void GRAPH_RDLOCK
 block_crypto_amend_cleanup(BlockDriverState *bs)
 {
     BlockCrypto *crypto = bs->opaque;
@@ -841,6 +841,8 @@ block_crypto_amend_options_luks(BlockDriverState *bs,
     QCryptoBlockAmendOptions *amend_options = NULL;
     int ret = -EINVAL;
 
+    assume_graph_lock(); /* FIXME */
+
     assert(crypto);
     assert(crypto->block);
 
diff --git a/block/mirror.c b/block/mirror.c
index aae4bebbb6..3cc0757a03 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -702,8 +702,12 @@ static int mirror_exit_common(Job *job)
      * mirror_top_bs from now on, so keep it drained. */
     bdrv_drained_begin(mirror_top_bs);
     bs_opaque->stop = true;
+
+    bdrv_graph_rdlock_main_loop();
     bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing,
                              &error_abort);
+    bdrv_graph_rdunlock_main_loop();
+
     if (!abort && s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) {
         BlockDriverState *backing = s->is_none_mode ? src : s->base;
         BlockDriverState *unfiltered_target = bdrv_skip_filters(target_bs);
@@ -1670,6 +1674,8 @@ static BlockJob *mirror_start_job(
     uint64_t target_perms, target_shared_perms;
     int ret;
 
+    GLOBAL_STATE_CODE();
+
     if (granularity == 0) {
         granularity = bdrv_get_default_bitmap_granularity(target);
     }
@@ -1906,8 +1912,10 @@ fail:
     }
 
     bs_opaque->stop = true;
+    bdrv_graph_rdlock_main_loop();
     bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing,
                              &error_abort);
+    bdrv_graph_rdunlock_main_loop();
     bdrv_replace_node(mirror_top_bs, mirror_top_bs->backing->bs, &error_abort);
 
     bdrv_unref(mirror_top_bs);
diff --git a/block/vmdk.c b/block/vmdk.c
index 58ce290e9c..84185b73a2 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -1309,6 +1309,8 @@ static int vmdk_open(BlockDriverState *bs, QDict *options, int flags,
     BDRVVmdkState *s = bs->opaque;
     uint32_t magic;
 
+    GRAPH_RDLOCK_GUARD_MAINLOOP();
+
     ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
     if (ret < 0) {
         return ret;