vfs: fix reference leak in d_prune_aliases()

In "d_prune_alias(): just lock the parent and call __dentry_kill()" the old
dget + d_drop + dput has been replaced with lock_parent + __dentry_kill;
unfortunately, dput() does more than just killing dentry - it also drops the
reference to parent.  New variant leaks that reference and needs dput(parent)
after killing the child off.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/dcache.c b/fs/dcache.c
index 3ffef7f4e5cdd9d00ca454130070f4619a8707d6..5bc72b07fde22bcbb00451c7522333e2aa273323 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -778,6 +778,7 @@ void d_prune_aliases(struct inode *inode)
                        struct dentry *parent = lock_parent(dentry);
                        if (likely(!dentry->d_lockref.count)) {
                                __dentry_kill(dentry);
+                               dput(parent);
                                goto restart;
                        }
                        if (parent)