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[PATCH v2 04/10] block.c: bdrv_replace_child_noperm: first remove the ch
From: |
Emanuele Giuseppe Esposito |
Subject: |
[PATCH v2 04/10] block.c: bdrv_replace_child_noperm: first remove the child, and then call ->detach() |
Date: |
Mon, 14 Mar 2022 09:18:48 -0400 |
Doing the opposite can make ->detach() (more precisely
bdrv_unapply_subtree_drain() in bdrv_child_cb_detach) undo the subtree_drain
just performed to protect the removal of the child from the graph,
thus making the fully-enabled assert_bdrv_graph_writable fail.
Note that assert_bdrv_graph_writable is not yet fully enabled.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
block.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/block.c b/block.c
index 372f16f4a0..d870ba5393 100644
--- a/block.c
+++ b/block.c
@@ -1448,6 +1448,11 @@ static void bdrv_child_cb_attach(BdrvChild *child)
bdrv_apply_subtree_drain(child, bs);
}
+/*
+ * Unapply the drain in the whole child subtree, as
+ * it has been already detached, and then remove from
+ * child->opaque->children.
+ */
static void bdrv_child_cb_detach(BdrvChild *child)
{
BlockDriverState *bs = child->opaque;
@@ -2864,14 +2869,18 @@ static void bdrv_replace_child_noperm(BdrvChild
**childp,
}
if (old_bs) {
- /* Detach first so that the recursive drain sections coming from @child
- * are already gone and we only end the drain sections that came from
- * elsewhere. */
+ /* First remove child from child->bs->parents list */
+ assert_bdrv_graph_writable(old_bs);
+ QLIST_REMOVE(child, next_parent);
+ /*
+ * Then call ->detach() cb.
+ * In child_of_bds case, update the child parent
+ * (child->opaque) ->children list and
+ * remove any drain left in the child subtree.
+ */
if (child->klass->detach) {
child->klass->detach(child);
}
- assert_bdrv_graph_writable(old_bs);
- QLIST_REMOVE(child, next_parent);
}
child->bs = new_bs;
--
2.31.1
- [PATCH v2 03/10] block/io.c: fix bdrv_child_cb_drained_begin invocations from a coroutine, (continued)
- [PATCH v2 03/10] block/io.c: fix bdrv_child_cb_drained_begin invocations from a coroutine, Emanuele Giuseppe Esposito, 2022/03/14
- [PATCH v2 07/10] test-bdrv-drain.c: remove test_detach_by_parent_cb(), Emanuele Giuseppe Esposito, 2022/03/14
- [PATCH v2 06/10] test-bdrv-drain.c: adapt test to support additional subtree drains, Emanuele Giuseppe Esposito, 2022/03/14
- [PATCH v2 05/10] block.c: bdrv_replace_child_noperm: first call ->attach(), and then add child, Emanuele Giuseppe Esposito, 2022/03/14
- [PATCH v2 01/10] drains: create bh only when polling, Emanuele Giuseppe Esposito, 2022/03/14
- [PATCH v2 09/10] child_job_drained_poll: override polling condition only when in home thread, Emanuele Giuseppe Esposito, 2022/03/14
- [PATCH v2 10/10] tests/qemu-iotests/030: test_stream_parallel should use auto_finalize=False, Emanuele Giuseppe Esposito, 2022/03/14
- [PATCH v2 02/10] bdrv_parent_drained_begin_single: handle calls from coroutine context, Emanuele Giuseppe Esposito, 2022/03/14
- [PATCH v2 08/10] tests/unit/test-bdrv-drain.c: graph setup functions can't run in coroutines, Emanuele Giuseppe Esposito, 2022/03/14
- [PATCH v2 04/10] block.c: bdrv_replace_child_noperm: first remove the child, and then call ->detach(),
Emanuele Giuseppe Esposito <=