From: Jeff Layton <jlayton@redhat.com>
Date: Mon, 28 Jun 2010 12:35:59 -0400
Subject: [fs] nfs: use nfs_refresh_inode in __nfs_revalidate_inode
Message-id: <1277728562-28052-2-git-send-email-jlayton@redhat.com>
Patchwork-id: 26583
O-Subject: [RHEL5.6 PATCH 1/4] BZ#601800: NFS: Convert __nfs_revalidate_inode()
	to use nfs_refresh_inode()
Bugzilla: 601800
RH-Acked-by: Steve Dickson <SteveD@redhat.com>

From: Trond Myklebust <Trond.Myklebust@netapp.com>

In the case where there are parallel RPC calls to the same inode, we may
receive stale metadata due to the lack of ordering, hence the sanity
checking of metadata in nfs_refresh_inode().
Currently, __nfs_revalidate_inode() is calling nfs_update_inode() directly,
without any further sanity checks, and hence may end up setting the inode
up with stale metadata.

Fix is to use nfs_refresh_inode() instead of nfs_update_inode().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 2a5c1a1..af87e3d 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -677,16 +677,13 @@ __nfs_revalidate_inode(struct nfs_server *server, struct inode *inode)
 		goto out;
 	}
 
-	spin_lock(&inode->i_lock);
-	status = nfs_update_inode(inode, &fattr);
+	status = nfs_refresh_inode(inode, &fattr);
 	if (status) {
-		spin_unlock(&inode->i_lock);
 		dfprintk(PAGECACHE, "nfs_revalidate_inode: (%s/%Ld) refresh failed, error=%d\n",
 			 inode->i_sb->s_id,
 			 (long long)NFS_FILEID(inode), status);
 		goto out;
 	}
-	spin_unlock(&inode->i_lock);
 
 	if (nfsi->cache_validity & NFS_INO_INVALID_ACL)
 		nfs_zap_acl_cache(inode);