NFSv4: Fix a potentially Oopsable condition in __nfs_idmap_unregister

Ensure that __nfs_idmap_unregister can be called twice without
consequences.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index e9b0c59..8b7e94a 100644 (file)
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -404,8 +404,10 @@ static struct key_type key_type_id_resolver_legacy = {
 
 static void __nfs_idmap_unregister(struct rpc_pipe *pipe)
 {
-       if (pipe->dentry)
+       if (pipe->dentry) {
                rpc_unlink(pipe->dentry);
+               pipe->dentry = NULL;
+       }
 }
 
 static int __nfs_idmap_register(struct dentry *dir,