NFSv4.1/pnfs: Add a tracepoint for return-on-close events

Allow tracing of return-on-close.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfs4trace.h

@@ -1136,6 +1136,7 @@ TRACE_EVENT(nfs4_layoutget,
 
 DEFINE_NFS4_INODE_EVENT(nfs4_layoutcommit);
 DEFINE_NFS4_INODE_EVENT(nfs4_layoutreturn);
+DEFINE_NFS4_INODE_EVENT(nfs4_layoutreturn_on_close);
 
 #endif /* CONFIG_NFS_V4_1 */
 

fs/nfs/pnfs.c

@@ -1144,6 +1144,7 @@ void pnfs_roc_set_barrier(struct inode *ino, u32 barrier)
 	if (pnfs_seqid_is_newer(barrier, lo->plh_barrier))
 		lo->plh_barrier = barrier;
 	spin_unlock(&ino->i_lock);
+	trace_nfs4_layoutreturn_on_close(ino, 0);
 }
 
 void pnfs_roc_get_barrier(struct inode *ino, u32 *barrier)