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authorKevin Wolf <kwolf@redhat.com>2016-05-23 15:52:26 +0200
committerKevin Wolf <kwolf@redhat.com>2016-05-25 19:04:10 +0200
commite9740bc6d466df53efe4b8f797e99d16212799d0 (patch)
treef3879f7fd401b7d03ca53414a6ea4e8508c26d18 /block.c
parent109525ad6a2f5d720ee0802df7ab1e3decbeeb21 (diff)
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block: Introduce bdrv_replace_child()
This adds a common function that is called when attaching a new child to a parent, removing a child from a parent and when reconfiguring the graph so that an existing child points to a different node now. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com>
Diffstat (limited to 'block.c')
-rw-r--r--block.c26
1 files changed, 20 insertions, 6 deletions
diff --git a/block.c b/block.c
index 38df365..351344e 100644
--- a/block.c
+++ b/block.c
@@ -1150,18 +1150,32 @@ static int bdrv_fill_options(QDict **options, const char *filename,
return 0;
}
+static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs)
+{
+ BlockDriverState *old_bs = child->bs;
+
+ if (old_bs) {
+ QLIST_REMOVE(child, next_parent);
+ }
+ if (new_bs) {
+ QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent);
+ }
+
+ child->bs = new_bs;
+}
+
BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
const char *child_name,
const BdrvChildRole *child_role)
{
BdrvChild *child = g_new(BdrvChild, 1);
*child = (BdrvChild) {
- .bs = child_bs,
+ .bs = NULL,
.name = g_strdup(child_name),
.role = child_role,
};
- QLIST_INSERT_HEAD(&child_bs->parents, child, next_parent);
+ bdrv_replace_child(child, child_bs);
return child;
}
@@ -1182,7 +1196,9 @@ static void bdrv_detach_child(BdrvChild *child)
QLIST_REMOVE(child, next);
child->next.le_prev = NULL;
}
- QLIST_REMOVE(child, next_parent);
+
+ bdrv_replace_child(child, NULL);
+
g_free(child->name);
g_free(child);
}
@@ -2203,10 +2219,8 @@ static void change_parent_backing_link(BlockDriverState *from,
QLIST_FOREACH_SAFE(c, &from->parents, next_parent, next) {
assert(c->role != &child_backing);
- c->bs = to;
- QLIST_REMOVE(c, next_parent);
- QLIST_INSERT_HEAD(&to->parents, c, next_parent);
bdrv_ref(to);
+ bdrv_replace_child(c, to);
bdrv_unref(from);
}
}