NFS: Detect loops in a readdir due to bad cookies

Some filesystems (such as ext4) can return the same cookie value for
multiple files.  If we try to start a readdir with one of these cookies,
the server will return the first file found with a cookie of the same
value.  This can cause the client to enter an infinite loop.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 4b851a02f7f3..4179c368844b 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -100,6 +100,8 @@ struct nfs_open_context {
 struct nfs_open_dir_context {
         struct rpc_cred *cred;
         __u64 dir_cookie;
+        __u64 dup_cookie;
+        int duped;
 };
 
 /*