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[PULL 16/39] block: add bdrv_replace_child_safe() transaction action
From: |
Kevin Wolf |
Subject: |
[PULL 16/39] block: add bdrv_replace_child_safe() transaction action |
Date: |
Fri, 30 Apr 2021 12:51:24 +0200 |
From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
To be used in the following commit.
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210428151804.439460-17-vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
block.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 54 insertions(+)
diff --git a/block.c b/block.c
index 98b7bc179c..a5305662dc 100644
--- a/block.c
+++ b/block.c
@@ -83,6 +83,9 @@ static BlockDriverState *bdrv_open_inherit(const char
*filename,
BdrvChildRole child_role,
Error **errp);
+static void bdrv_replace_child_noperm(BdrvChild *child,
+ BlockDriverState *new_bs);
+
static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue
*queue, Error **errp);
static void bdrv_reopen_commit(BDRVReopenState *reopen_state);
@@ -2237,6 +2240,57 @@ static int bdrv_drv_set_perm(BlockDriverState *bs,
uint64_t perm,
return 0;
}
+typedef struct BdrvReplaceChildState {
+ BdrvChild *child;
+ BlockDriverState *old_bs;
+} BdrvReplaceChildState;
+
+static void bdrv_replace_child_commit(void *opaque)
+{
+ BdrvReplaceChildState *s = opaque;
+
+ bdrv_unref(s->old_bs);
+}
+
+static void bdrv_replace_child_abort(void *opaque)
+{
+ BdrvReplaceChildState *s = 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_unref(new_bs);
+}
+
+static TransactionActionDrv bdrv_replace_child_drv = {
+ .commit = bdrv_replace_child_commit,
+ .abort = bdrv_replace_child_abort,
+ .clean = g_free,
+};
+
+/*
+ * bdrv_replace_child_safe
+ *
+ * Note: real unref of old_bs is done only on commit.
+ */
+__attribute__((unused))
+static void bdrv_replace_child_safe(BdrvChild *child, BlockDriverState *new_bs,
+ Transaction *tran)
+{
+ BdrvReplaceChildState *s = g_new(BdrvReplaceChildState, 1);
+ *s = (BdrvReplaceChildState) {
+ .child = child,
+ .old_bs = child->bs,
+ };
+ tran_add(tran, &bdrv_replace_child_drv, s);
+
+ if (new_bs) {
+ bdrv_ref(new_bs);
+ }
+ bdrv_replace_child_noperm(child, new_bs);
+ /* old_bs reference is transparently moved from @child to @s */
+}
+
/*
* Check whether permissions on this node can be changed in a way that
* @cumulative_perms and @cumulative_shared_perms are the new cumulative
--
2.30.2
- [PULL 10/39] block: refactor bdrv_child* permission functions, (continued)
- [PULL 10/39] block: refactor bdrv_child* permission functions, Kevin Wolf, 2021/04/30
- [PULL 12/39] block: inline bdrv_child_*() permission functions calls, Kevin Wolf, 2021/04/30
- [PULL 13/39] block: use topological sort for permission update, Kevin Wolf, 2021/04/30
- [PULL 14/39] block: add bdrv_drv_set_perm transaction action, Kevin Wolf, 2021/04/30
- [PULL 15/39] block: add bdrv_list_* permission update functions, Kevin Wolf, 2021/04/30
- [PULL 17/39] block: fix bdrv_replace_node_common, Kevin Wolf, 2021/04/30
- [PULL 19/39] block: add bdrv_attach_child_noperm() transaction action, Kevin Wolf, 2021/04/30
- [PULL 18/39] block: add bdrv_attach_child_common() transaction action, Kevin Wolf, 2021/04/30
- [PULL 20/39] block: split out bdrv_replace_node_noperm(), Kevin Wolf, 2021/04/30
- [PULL 16/39] block: add bdrv_replace_child_safe() transaction action,
Kevin Wolf <=
- [PULL 23/39] block: introduce bdrv_drop_filter(), Kevin Wolf, 2021/04/30
- [PULL 22/39] block: add bdrv_remove_filter_or_cow transaction action, Kevin Wolf, 2021/04/30
- [PULL 21/39] block: adapt bdrv_append() for inserting filters, Kevin Wolf, 2021/04/30
- [PULL 24/39] block/backup-top: drop .active, Kevin Wolf, 2021/04/30
- [PULL 25/39] block: drop ignore_children for permission update functions, Kevin Wolf, 2021/04/30
- [PULL 26/39] block: make bdrv_unset_inherits_from to be a transaction action, Kevin Wolf, 2021/04/30
- [PULL 28/39] block: add bdrv_set_backing_noperm() transaction action, Kevin Wolf, 2021/04/30
- [PULL 29/39] block: bdrv_reopen_multiple(): move bdrv_flush to separate pre-prepare, Kevin Wolf, 2021/04/30
- [PULL 34/39] block: refactor bdrv_child_set_perm_safe() transaction action, Kevin Wolf, 2021/04/30
- [PULL 33/39] block: inline bdrv_replace_child(), Kevin Wolf, 2021/04/30