pnfs: Prepare for flexfiles by pulling out common code

The flexfilelayout driver will share some common code
with the filelayout driver. This set of changes refactors
that common code out to avoid any module depenencies.

Signed-off-by: Tom Haynes <loghyr@primarydata.com>
diff --git a/fs/nfs/filelayout/filelayoutdev.c b/fs/nfs/filelayout/filelayoutdev.c
index bfecac7..d21080a 100644
--- a/fs/nfs/filelayout/filelayoutdev.c
+++ b/fs/nfs/filelayout/filelayoutdev.c
@@ -708,7 +708,7 @@
 	if (ds == NULL) {
 		printk(KERN_ERR "NFS: %s: No data server for offset index %d\n",
 			__func__, ds_idx);
-		filelayout_mark_devid_invalid(devid);
+		pnfs_generic_mark_devid_invalid(devid);
 		goto out;
 	}
 	smp_rmb();