NFSv4.1: filelayout driver specific code for COMMIT

Implement all the hooks created in the previous patches.
This requires exporting quite a few functions and adding a few
structure fields.

Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index f38813a..c675659 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -259,6 +259,7 @@
 		pnfs_free_lseg_list(&free_me);
 	}
 }
+EXPORT_SYMBOL_GPL(put_lseg);
 
 static bool
 should_free_lseg(u32 lseg_iomode, u32 recall_iomode)