block: Mark bdrv_attach_child() GRAPH_WRLOCK

Instead of taking the writer lock internally, require callers to already
hold it when calling bdrv_attach_child_common(). These callers will
typically already hold the graph lock once the locking work is
completed, which means that they can't call functions that take it
internally.

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: <20230911094620.45040-13-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

2 files changed, 24 insertions, 0 deletions

diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c
index 89c8fa6780..6d33249656 100644
--- a/tests/unit/test-bdrv-drain.c
+++ b/tests/unit/test-bdrv-drain.c
@@ -1055,8 +1055,10 @@ static void do_test_delete_by_drain(bool detach_instead_of_delete,
 
     null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
                         &error_abort);
+    bdrv_graph_wrlock(NULL);
     bdrv_attach_child(bs, null_bs, "null-child", &child_of_bds,
                       BDRV_CHILD_DATA, &error_abort);
+    bdrv_graph_wrunlock();
 
     /* This child will be the one to pass to requests through to, and
      * it will stall until a drain occurs */
@@ -1064,17 +1066,21 @@ static void do_test_delete_by_drain(bool detach_instead_of_delete,
                                     &error_abort);
     child_bs->total_sectors = 65536 >> BDRV_SECTOR_BITS;
     /* Takes our reference to child_bs */
+    bdrv_graph_wrlock(NULL);
     tts->wait_child = bdrv_attach_child(bs, child_bs, "wait-child",
                                         &child_of_bds,
                                         BDRV_CHILD_DATA | BDRV_CHILD_PRIMARY,
                                         &error_abort);
+    bdrv_graph_wrunlock();
 
     /* This child is just there to be deleted
      * (for detach_instead_of_delete == true) */
     null_bs = bdrv_open("null-co://", NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
                         &error_abort);
+    bdrv_graph_wrlock(NULL);
     bdrv_attach_child(bs, null_bs, "null-child", &child_of_bds, BDRV_CHILD_DATA,
                       &error_abort);
+    bdrv_graph_wrunlock();
 
     blk = blk_new(qemu_get_aio_context(), BLK_PERM_ALL, BLK_PERM_ALL);
     blk_insert_bs(blk, bs, &error_abort);
@@ -1159,9 +1165,11 @@ static void detach_indirect_bh(void *opaque)
     bdrv_unref_child(data->parent_b, data->child_b);
 
     bdrv_ref(data->c);
+    bdrv_graph_wrlock(NULL);
     data->child_c = bdrv_attach_child(data->parent_b, data->c, "PB-C",
                                       &child_of_bds, BDRV_CHILD_DATA,
                                       &error_abort);
+    bdrv_graph_wrunlock();
 }
 
 static void detach_by_parent_aio_cb(void *opaque, int ret)
@@ -1258,6 +1266,7 @@ static void test_detach_indirect(bool by_parent_cb)
     /* Set child relationships */
     bdrv_ref(b);
     bdrv_ref(a);
+    bdrv_graph_wrlock(NULL);
     child_b = bdrv_attach_child(parent_b, b, "PB-B", &child_of_bds,
                                 BDRV_CHILD_DATA, &error_abort);
     child_a = bdrv_attach_child(parent_b, a, "PB-A", &child_of_bds,
@@ -1267,6 +1276,7 @@ static void test_detach_indirect(bool by_parent_cb)
     bdrv_attach_child(parent_a, a, "PA-A",
                       by_parent_cb ? &child_of_bds : &detach_by_driver_cb_class,
                       BDRV_CHILD_DATA, &error_abort);
+    bdrv_graph_wrunlock();
 
     g_assert_cmpint(parent_a->refcnt, ==, 1);
     g_assert_cmpint(parent_b->refcnt, ==, 1);
@@ -1685,6 +1695,7 @@ static void test_drop_intermediate_poll(void)
      * Establish the chain last, so the chain links are the first
      * elements in the BDS.parents lists
      */
+    bdrv_graph_wrlock(NULL);
     for (i = 0; i < 3; i++) {
         if (i) {
             /* Takes the reference to chain[i - 1] */
@@ -1692,6 +1703,7 @@ static void test_drop_intermediate_poll(void)
                               &chain_child_class, BDRV_CHILD_COW, &error_abort);
         }
     }
+    bdrv_graph_wrunlock();
 
     job = block_job_create("job", &test_simple_job_driver, NULL, job_node,
                            0, BLK_PERM_ALL, 0, 0, NULL, NULL, &error_abort);
@@ -1936,8 +1948,10 @@ static void do_test_replace_child_mid_drain(int old_drain_count,
     new_child_bs->total_sectors = 1;
 
     bdrv_ref(old_child_bs);
+    bdrv_graph_wrlock(NULL);
     bdrv_attach_child(parent_bs, old_child_bs, "child", &child_of_bds,
                       BDRV_CHILD_COW, &error_abort);
+    bdrv_graph_wrunlock();
     parent_s->setup_completed = true;
 
     for (i = 0; i < old_drain_count; i++) {
diff --git a/tests/unit/test-bdrv-graph-mod.c b/tests/unit/test-bdrv-graph-mod.c
index d8503165b3..621e616655 100644
--- a/tests/unit/test-bdrv-graph-mod.c
+++ b/tests/unit/test-bdrv-graph-mod.c
@@ -137,8 +137,10 @@ static void test_update_perm_tree(void)
 
     blk_insert_bs(root, bs, &error_abort);
 
+    bdrv_graph_wrlock(NULL);
     bdrv_attach_child(filter, bs, "child", &child_of_bds,
                       BDRV_CHILD_DATA, &error_abort);
+    bdrv_graph_wrunlock();
 
     aio_context_acquire(qemu_get_aio_context());
     ret = bdrv_append(filter, bs, NULL);
@@ -205,8 +207,10 @@ static void test_should_update_child(void)
     bdrv_set_backing_hd(target, bs, &error_abort);
 
     g_assert(target->backing->bs == bs);
+    bdrv_graph_wrlock(NULL);
     bdrv_attach_child(filter, target, "target", &child_of_bds,
                       BDRV_CHILD_DATA, &error_abort);
+    bdrv_graph_wrunlock();
     aio_context_acquire(qemu_get_aio_context());
     bdrv_append(filter, bs, &error_abort);
     aio_context_release(qemu_get_aio_context());
@@ -236,6 +240,7 @@ static void test_parallel_exclusive_write(void)
      */
     bdrv_ref(base);
 
+    bdrv_graph_wrlock(NULL);
     bdrv_attach_child(top, fl1, "backing", &child_of_bds,
                       BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
                       &error_abort);
@@ -245,6 +250,7 @@ static void test_parallel_exclusive_write(void)
     bdrv_attach_child(fl2, base, "backing", &child_of_bds,
                       BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
                       &error_abort);
+    bdrv_graph_wrunlock();
 
     bdrv_replace_node(fl1, fl2, &error_abort);
 
@@ -349,6 +355,7 @@ static void test_parallel_perm_update(void)
      */
     bdrv_ref(base);
 
+    bdrv_graph_wrlock(NULL);
     bdrv_attach_child(top, ws, "file", &child_of_bds, BDRV_CHILD_DATA,
                       &error_abort);
     c_fl1 = bdrv_attach_child(ws, fl1, "first", &child_of_bds,
@@ -361,6 +368,7 @@ static void test_parallel_perm_update(void)
     bdrv_attach_child(fl2, base, "backing", &child_of_bds,
                       BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
                       &error_abort);
+    bdrv_graph_wrunlock();
 
     /* Select fl1 as first child to be active */
     s->selected = c_fl1;
@@ -410,9 +418,11 @@ static void test_append_greedy_filter(void)
     BlockDriverState *base = no_perm_node("base");
     BlockDriverState *fl = exclusive_writer_node("fl1");
 
+    bdrv_graph_wrlock(NULL);
     bdrv_attach_child(top, base, "backing", &child_of_bds,
                       BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
                       &error_abort);
+    bdrv_graph_wrunlock();
 
     aio_context_acquire(qemu_get_aio_context());
     bdrv_append(fl, base, &error_abort);