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authorJianyu Zhan <nasa4836@gmail.com>2014-04-17 13:52:10 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-04-25 23:25:13 +0400
commitc1befb885939cdaaf420c10bbe9ff57aa00446ea (patch)
treee46f5797e3b17838b41f874f70facaf7b52bfea5 /fs/kernfs
parenta798c10faf62a505d24e5f6213fbaf904a39623f (diff)
downloadlinux-c1befb885939cdaaf420c10bbe9ff57aa00446ea.tar.xz
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>
Diffstat (limited to 'fs/kernfs')
-rw-r--r--fs/kernfs/dir.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 78f3403300af..ac127cd008bf 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -232,9 +232,6 @@ static int kernfs_link_sibling(struct kernfs_node *kn)
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 @@ static int kernfs_link_sibling(struct kernfs_node *kn)
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;
}