From 4e99a1ff3410c627a428d5ddb6cd2e7bc908a486 Mon Sep 17 00:00:00 2001
From: Trond Myklebust <Trond.Myklebust@netapp.com>
Date: Thu, 6 Mar 2008 12:34:59 -0500
Subject: NFS: Fix dentry revalidation for NFSv4 referrals and mountpoint
 crossings

As long as the directory contents haven't changed, we should just let the
path walk proceed to cross the mountpoint. Apart from being an optimisation
in the case of 'nohide' mountpoint traversals, it also fixes an issue with
referrals: referral inodes don't have valid filehandles, so calling
nfs_revalidate_inode() on them is a bug.

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

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index ae04892..6cea747 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -710,6 +710,8 @@ int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd)
 {
 	struct nfs_server *server = NFS_SERVER(inode);
 
+	if (test_bit(NFS_INO_MOUNTPOINT, &NFS_I(inode)->flags))
+		return 0;
 	if (nd != NULL) {
 		/* VFS wants an on-the-wire revalidation */
 		if (nd->flags & LOOKUP_REVAL)
-- 
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