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[PULL 02/13] block: Manipulate children list in .attach/.detach
From: |
Kevin Wolf |
Subject: |
[PULL 02/13] block: Manipulate children list in .attach/.detach |
Date: |
Mon, 15 Nov 2021 15:53:58 +0100 |
From: Hanna Reitz <hreitz@redhat.com>
The children list is specific to BDS parents. We should not modify it
in the general children modification code, but let BDS parents deal with
it in their .attach() and .detach() methods.
This also has the advantage that a BdrvChild is removed from the
children list before its .bs pointer can become NULL. BDS parents
generally assume that their children's .bs pointer is never NULL, so
this is actually a bug fix.
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211111120829.81329-3-hreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
block.c | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)
diff --git a/block.c b/block.c
index 580cb77a70..ca024ffced 100644
--- a/block.c
+++ b/block.c
@@ -1387,6 +1387,8 @@ static void bdrv_child_cb_attach(BdrvChild *child)
{
BlockDriverState *bs = child->opaque;
+ QLIST_INSERT_HEAD(&bs->children, child, next);
+
if (child->role & BDRV_CHILD_COW) {
bdrv_backing_attach(child);
}
@@ -1403,6 +1405,8 @@ static void bdrv_child_cb_detach(BdrvChild *child)
}
bdrv_unapply_subtree_drain(child, bs);
+
+ QLIST_REMOVE(child, next);
}
static int bdrv_child_cb_update_filename(BdrvChild *c, BlockDriverState *base,
@@ -2747,7 +2751,7 @@ static void bdrv_child_free(void *opaque)
static void bdrv_remove_empty_child(BdrvChild *child)
{
assert(!child->bs);
- QLIST_SAFE_REMOVE(child, next);
+ assert(!child->next.le_prev); /* not in children list */
bdrv_child_free(child);
}
@@ -2913,12 +2917,6 @@ static int bdrv_attach_child_noperm(BlockDriverState
*parent_bs,
return ret;
}
- QLIST_INSERT_HEAD(&parent_bs->children, *child, next);
- /*
- * child is removed in bdrv_attach_child_common_abort(), so don't care to
- * abort this change separately.
- */
-
return 0;
}
@@ -4851,7 +4849,6 @@ static void bdrv_remove_filter_or_cow_child_abort(void
*opaque)
BdrvRemoveFilterOrCowChild *s = opaque;
BlockDriverState *parent_bs = s->child->opaque;
- QLIST_INSERT_HEAD(&parent_bs->children, s->child, next);
if (s->is_backing) {
parent_bs->backing = s->child;
} else {
@@ -4906,7 +4903,6 @@ static void
bdrv_remove_file_or_backing_child(BlockDriverState *bs,
};
tran_add(tran, &bdrv_remove_filter_or_cow_child_drv, s);
- QLIST_SAFE_REMOVE(child, next);
if (s->is_backing) {
bs->backing = NULL;
} else {
--
2.31.1
- [PULL 00/13] Block layer patches, Kevin Wolf, 2021/11/15
- [PULL 01/13] stream: Traverse graph after modification, Kevin Wolf, 2021/11/15
- [PULL 04/13] block: Drop detached child from ignore list, Kevin Wolf, 2021/11/15
- [PULL 02/13] block: Manipulate children list in .attach/.detach,
Kevin Wolf <=
- [PULL 03/13] block: Unite remove_empty_child and child_free, Kevin Wolf, 2021/11/15
- [PULL 05/13] block: Pass BdrvChild ** to replace_child_noperm, Kevin Wolf, 2021/11/15
- [PULL 06/13] block: Restructure remove_file_or_backing_child(), Kevin Wolf, 2021/11/15
- [PULL 08/13] block: Let replace_child_tran keep indirect pointer, Kevin Wolf, 2021/11/15
- [PULL 11/13] docs: Deprecate incorrectly typed device_add arguments, Kevin Wolf, 2021/11/15
- [PULL 12/13] file-posix: Fix alignment after reopen changing O_DIRECT, Kevin Wolf, 2021/11/15
- [PULL 10/13] iotests/030: Unthrottle parallel jobs in reverse, Kevin Wolf, 2021/11/15
- [PULL 09/13] block: Let replace_child_noperm free children, Kevin Wolf, 2021/11/15
- [PULL 13/13] softmmu/qdev-monitor: fix use-after-free in qdev_set_id(), Kevin Wolf, 2021/11/15
- [PULL 07/13] transactions: Invoke clean() after everything else, Kevin Wolf, 2021/11/15