pnfs/filelayout: add tracepoint to getdeviceinfo

While decoding filelayout getdeviceinfo received, print out the
information about the location of data servers (IPs).

Generic getdeviceinfo tracepoints prints the MDS's ip for the
dstaddr. In this patch, separate the MDS's address from the
DS's addresses.

Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

Author: olgakorn1

fs/nfs/filelayout/filelayoutdev.c

@@ -35,6 +35,7 @@
 #include "../internal.h"
 #include "../nfs4session.h"
 #include "filelayout.h"
+#include "../nfs4trace.h"
 
 #define NFSDBG_FACILITY		NFSDBG_PNFS_LD
 
@@ -172,6 +173,7 @@ nfs4_fl_alloc_deviceid_node(struct nfs_server *server, struct pnfs_device *pdev,
 		dsaddr->ds_list[i] = nfs4_pnfs_ds_add(&dsaddrs, gfp_flags);
 		if (!dsaddr->ds_list[i])
 			goto out_err_drain_dsaddrs;
+		trace_fl_getdevinfo(server, &pdev->dev_id, dsaddr->ds_list[i]->ds_remotestr);
 
 		/* If DS was already in cache, free ds addrs */
 		while (!list_empty(&dsaddrs)) {

fs/nfs/nfs4trace.c

@@ -28,4 +28,6 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(pnfs_mds_fallback_write_pagelist);
 EXPORT_TRACEPOINT_SYMBOL_GPL(ff_layout_read_error);
 EXPORT_TRACEPOINT_SYMBOL_GPL(ff_layout_write_error);
 EXPORT_TRACEPOINT_SYMBOL_GPL(ff_layout_commit_error);
+
+EXPORT_TRACEPOINT_SYMBOL_GPL(fl_getdevinfo);
 #endif

fs/nfs/nfs4trace.h

@@ -1991,6 +1991,34 @@ DECLARE_EVENT_CLASS(nfs4_deviceid_status,
 DEFINE_PNFS_DEVICEID_STATUS(nfs4_getdeviceinfo);
 DEFINE_PNFS_DEVICEID_STATUS(nfs4_find_deviceid);
 
+TRACE_EVENT(fl_getdevinfo,
+		TP_PROTO(
+			const struct nfs_server *server,
+			const struct nfs4_deviceid *deviceid,
+			char *ds_remotestr
+		),
+		TP_ARGS(server, deviceid, ds_remotestr),
+
+		TP_STRUCT__entry(
+			__string(mds_addr, server->nfs_client->cl_hostname)
+			__array(unsigned char, deviceid, NFS4_DEVICEID4_SIZE)
+			__string(ds_ips, ds_remotestr)
+		),
+
+		TP_fast_assign(
+			__assign_str(mds_addr, server->nfs_client->cl_hostname);
+			__assign_str(ds_ips, ds_remotestr);
+			memcpy(__entry->deviceid, deviceid->data,
+			       NFS4_DEVICEID4_SIZE);
+		),
+		TP_printk(
+			"deviceid=%s, mds_addr=%s, ds_ips=%s",
+			__print_hex(__entry->deviceid, NFS4_DEVICEID4_SIZE),
+			__get_str(mds_addr),
+			__get_str(ds_ips)
+		)
+);
+
 DECLARE_EVENT_CLASS(nfs4_flexfiles_io_event,
 		TP_PROTO(
 			const struct nfs_pgio_header *hdr