NFSv4.1 add nfs_inode book keeping for mdsthreshold

Keep track of the number of bytes read or written via buffered, direct, and
mem-mapped i/o for use by mdsthreshold size_io hints.

Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index ce910cb..b23cfc1 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -202,6 +202,9 @@
 	/* pNFS layout information */
 	struct pnfs_layout_hdr *layout;
 #endif /* CONFIG_NFS_V4*/
+	/* how many bytes have been written/read and how many bytes queued up */
+	__u64 write_io;
+	__u64 read_io;
 #ifdef CONFIG_NFS_FSCACHE
 	struct fscache_cookie	*fscache;
 #endif