NFS: Fix a connectathon regression in NFSv3 and NFSv4

We're failing basic test6 against Linux servers because they lack a correct
change attribute. The fix is to assume that we always want to invalidate
the readdir caches when we call update_changeattr and/or
nfs_post_op_update_inode on a directory.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/inode.c

@@ -876,11 +876,19 @@ int nfs_post_op_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 {
 	struct nfs_inode *nfsi = NFS_I(inode);
 
-	if (fattr->valid & NFS_ATTR_FATTR)
+	if (fattr->valid & NFS_ATTR_FATTR) {
+		if (S_ISDIR(inode->i_mode)) {
+			spin_lock(&inode->i_lock);
+			nfsi->cache_validity |= NFS_INO_INVALID_DATA;
+			spin_unlock(&inode->i_lock);
+		}
 		return nfs_refresh_inode(inode, fattr);
+	}
 
 	spin_lock(&inode->i_lock);
 	nfsi->cache_validity |= NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE;
+	if (S_ISDIR(inode->i_mode))
+		nfsi->cache_validity |= NFS_INO_INVALID_DATA;
 	spin_unlock(&inode->i_lock);
 	return 0;
 }

fs/nfs/nfs4proc.c

@@ -208,12 +208,10 @@ static void update_changeattr(struct inode *dir, struct nfs4_change_info *cinfo)
 	struct nfs_inode *nfsi = NFS_I(dir);
 
 	spin_lock(&dir->i_lock);
-	if (cinfo->after != nfsi->change_attr) {
 	nfsi->cache_validity |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA;
 	if (!cinfo->atomic || cinfo->before != nfsi->change_attr)
 		nfsi->cache_change_attribute = jiffies;
 	nfsi->change_attr = cinfo->after;
-	}
 	spin_unlock(&dir->i_lock);
 }