kernfs: fix a subdir count leak
Currently kernfs_link_sibling() increates parent->dir.subdirs before
adding the node into parent's chidren rb tree.
Because it is possible that kernfs_link_sibling() couldn't find
a suitable slot and bail out, this leads to a mismatch between
elevated subdir count with actual children node numbers.
This patches fix this problem, by moving the subdir accouting
after the actual addtion happening.
Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 78f3403..ac127cd 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -232,9 +232,6 @@
struct rb_node **node = &kn->parent->dir.children.rb_node;
struct rb_node *parent = NULL;
- if (kernfs_type(kn) == KERNFS_DIR)
- kn->parent->dir.subdirs++;
-
while (*node) {
struct kernfs_node *pos;
int result;
@@ -249,9 +246,15 @@
else
return -EEXIST;
}
+
/* add new node and rebalance the tree */
rb_link_node(&kn->rb, parent, node);
rb_insert_color(&kn->rb, &kn->parent->dir.children);
+
+ /* successfully added, account subdir number */
+ if (kernfs_type(kn) == KERNFS_DIR)
+ kn->parent->dir.subdirs++;
+
return 0;
}