NFS: Add tracepoints for layouterror and layoutstats.

Allow tracing of the NFSv4.2 layouterror and layoutstats operations.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/nfs42proc.c

@@ -17,6 +17,7 @@
 #include "nfs4session.h"
 #include "internal.h"
 #include "delegation.h"
+#include "nfs4trace.h"
 
 #define NFSDBG_FACILITY NFSDBG_PROC
 static int nfs42_do_offload_cancel_async(struct file *dst, nfs4_stateid *std);
@@ -714,7 +715,7 @@ nfs42_layoutstat_done(struct rpc_task *task, void *calldata)
 
 	switch (task->tk_status) {
 	case 0:
-		break;
+		return;
 	case -NFS4ERR_BADHANDLE:
 	case -ESTALE:
 		pnfs_destroy_layout(NFS_I(inode));
@@ -760,6 +761,8 @@ nfs42_layoutstat_done(struct rpc_task *task, void *calldata)
 	case -EOPNOTSUPP:
 		NFS_SERVER(inode)->caps &= ~NFS_CAP_LAYOUTSTATS;
 	}
+
+	trace_nfs4_layoutstats(inode, &data->args.stateid, task->tk_status);
 }
 
 static void
@@ -882,7 +885,7 @@ nfs42_layouterror_done(struct rpc_task *task, void *calldata)
 
 	switch (task->tk_status) {
 	case 0:
-		break;
+		return;
 	case -NFS4ERR_BADHANDLE:
 	case -ESTALE:
 		pnfs_destroy_layout(NFS_I(inode));
@@ -926,6 +929,9 @@ nfs42_layouterror_done(struct rpc_task *task, void *calldata)
 	case -EOPNOTSUPP:
 		NFS_SERVER(inode)->caps &= ~NFS_CAP_LAYOUTERROR;
 	}
+
+	trace_nfs4_layouterror(inode, &data->args.errors[0].stateid,
+			       task->tk_status);
 }
 
 static void

fs/nfs/nfs4trace.h

@@ -1994,6 +1994,8 @@ TRACE_EVENT(nfs4_layoutget,
 DEFINE_NFS4_INODE_STATEID_EVENT(nfs4_layoutcommit);
 DEFINE_NFS4_INODE_STATEID_EVENT(nfs4_layoutreturn);
 DEFINE_NFS4_INODE_STATEID_EVENT(nfs4_layoutreturn_on_close);
+DEFINE_NFS4_INODE_STATEID_EVENT(nfs4_layouterror);
+DEFINE_NFS4_INODE_STATEID_EVENT(nfs4_layoutstats);
 
 TRACE_DEFINE_ENUM(PNFS_UPDATE_LAYOUT_UNKNOWN);
 TRACE_DEFINE_ENUM(PNFS_UPDATE_LAYOUT_NO_PNFS);