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[PULL 05/13] block: Pass BdrvChild ** to replace_child_noperm
From: |
Kevin Wolf |
Subject: |
[PULL 05/13] block: Pass BdrvChild ** to replace_child_noperm |
Date: |
Mon, 15 Nov 2021 15:54:01 +0100 |
From: Hanna Reitz <hreitz@redhat.com>
bdrv_replace_child_noperm() modifies BdrvChild.bs, and can potentially
set it to NULL. That is dangerous, because BDS parents generally assume
that their children's .bs pointer is never NULL. We therefore want to
let bdrv_replace_child_noperm() set the corresponding BdrvChild pointer
to NULL, too.
This patch lays the foundation for it by passing a BdrvChild ** pointer
to bdrv_replace_child_noperm() so that it can later use it to NULL the
BdrvChild pointer immediately after setting BdrvChild.bs to NULL.
(We will still need to undertake some intermediate steps, though.)
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20211111120829.81329-6-hreitz@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
block.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/block.c b/block.c
index c7d5aa5254..d668156eca 100644
--- a/block.c
+++ b/block.c
@@ -87,7 +87,7 @@ static BlockDriverState *bdrv_open_inherit(const char
*filename,
static bool bdrv_recurse_has_child(BlockDriverState *bs,
BlockDriverState *child);
-static void bdrv_replace_child_noperm(BdrvChild *child,
+static void bdrv_replace_child_noperm(BdrvChild **child,
BlockDriverState *new_bs);
static void bdrv_remove_file_or_backing_child(BlockDriverState *bs,
BdrvChild *child,
@@ -2270,7 +2270,7 @@ static void bdrv_replace_child_abort(void *opaque)
BlockDriverState *new_bs = s->child->bs;
/* old_bs reference is transparently moved from @s to @s->child */
- bdrv_replace_child_noperm(s->child, s->old_bs);
+ bdrv_replace_child_noperm(&s->child, s->old_bs);
bdrv_unref(new_bs);
}
@@ -2300,7 +2300,7 @@ static void bdrv_replace_child_tran(BdrvChild *child,
BlockDriverState *new_bs,
if (new_bs) {
bdrv_ref(new_bs);
}
- bdrv_replace_child_noperm(child, new_bs);
+ bdrv_replace_child_noperm(&child, new_bs);
/* old_bs reference is transparently moved from @child to @s */
}
@@ -2672,9 +2672,10 @@ uint64_t bdrv_qapi_perm_to_blk_perm(BlockPermission
qapi_perm)
return permissions[qapi_perm];
}
-static void bdrv_replace_child_noperm(BdrvChild *child,
+static void bdrv_replace_child_noperm(BdrvChild **childp,
BlockDriverState *new_bs)
{
+ BdrvChild *child = *childp;
BlockDriverState *old_bs = child->bs;
int new_bs_quiesce_counter;
int drain_saldo;
@@ -2767,7 +2768,7 @@ static void bdrv_attach_child_common_abort(void *opaque)
BdrvChild *child = *s->child;
BlockDriverState *bs = child->bs;
- bdrv_replace_child_noperm(child, NULL);
+ bdrv_replace_child_noperm(s->child, NULL);
if (bdrv_get_aio_context(bs) != s->old_child_ctx) {
bdrv_try_set_aio_context(bs, s->old_child_ctx, &error_abort);
@@ -2867,7 +2868,7 @@ static int bdrv_attach_child_common(BlockDriverState
*child_bs,
}
bdrv_ref(child_bs);
- bdrv_replace_child_noperm(new_child, child_bs);
+ bdrv_replace_child_noperm(&new_child, child_bs);
*child = new_child;
@@ -2922,12 +2923,12 @@ static int bdrv_attach_child_noperm(BlockDriverState
*parent_bs,
return 0;
}
-static void bdrv_detach_child(BdrvChild *child)
+static void bdrv_detach_child(BdrvChild **childp)
{
- BlockDriverState *old_bs = child->bs;
+ BlockDriverState *old_bs = (*childp)->bs;
- bdrv_replace_child_noperm(child, NULL);
- bdrv_child_free(child);
+ bdrv_replace_child_noperm(childp, NULL);
+ bdrv_child_free(*childp);
if (old_bs) {
/*
@@ -3033,7 +3034,7 @@ void bdrv_root_unref_child(BdrvChild *child)
BlockDriverState *child_bs;
child_bs = child->bs;
- bdrv_detach_child(child);
+ bdrv_detach_child(&child);
bdrv_unref(child_bs);
}
--
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, 2021/11/15
- [PULL 05/13] block: Pass BdrvChild ** to replace_child_noperm,
Kevin Wolf <=
- [PULL 06/13] block: Restructure remove_file_or_backing_child(), Kevin Wolf, 2021/11/15
- [PULL 10/13] iotests/030: Unthrottle parallel jobs in reverse, Kevin Wolf, 2021/11/15
- [PULL 11/13] docs: Deprecate incorrectly typed device_add arguments, Kevin Wolf, 2021/11/15
- [PULL 08/13] block: Let replace_child_tran keep indirect pointer, Kevin Wolf, 2021/11/15
- [PULL 03/13] block: Unite remove_empty_child and child_free, Kevin Wolf, 2021/11/15
- [PULL 12/13] file-posix: Fix alignment after reopen changing O_DIRECT, 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
- [PULL 09/13] block: Let replace_child_noperm free children, Kevin Wolf, 2021/11/15
- Re: [PULL 00/13] Block layer patches, Richard Henderson, 2021/11/15