[PATCH v2] pnfs: add pnfs_ds_connect trace point

[Tigran Mkrtchyan <tigran.mkrtchyan@xxxxxxx>]

This tracepoint aims to expose pnfs DS connect status

Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@xxxxxxx>
Reviewed-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
---
 fs/nfs/nfs4trace.c |  1 +
 fs/nfs/nfs4trace.h | 26 ++++++++++++++++++++++++++
 fs/nfs/pnfs_nfs.c  | 14 +++++++++-----
 3 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/fs/nfs/nfs4trace.c b/fs/nfs/nfs4trace.c
index 389941ccc9c9..436763a559cd 100644
--- a/fs/nfs/nfs4trace.c
+++ b/fs/nfs/nfs4trace.c
@@ -26,6 +26,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(pnfs_mds_fallback_read_done);
 EXPORT_TRACEPOINT_SYMBOL_GPL(pnfs_mds_fallback_write_done);
 EXPORT_TRACEPOINT_SYMBOL_GPL(pnfs_mds_fallback_read_pagelist);
 EXPORT_TRACEPOINT_SYMBOL_GPL(pnfs_mds_fallback_write_pagelist);
+EXPORT_TRACEPOINT_SYMBOL_GPL(pnfs_ds_connect);
 
 EXPORT_TRACEPOINT_SYMBOL_GPL(ff_layout_read_error);
 EXPORT_TRACEPOINT_SYMBOL_GPL(ff_layout_write_error);
diff --git a/fs/nfs/nfs4trace.h b/fs/nfs/nfs4trace.h
index deab4c0e21a0..f6fc38bce9d0 100644
--- a/fs/nfs/nfs4trace.h
+++ b/fs/nfs/nfs4trace.h
@@ -273,6 +273,32 @@ TRACE_EVENT(nfs4_cb_offload,
 			show_nfs_stable_how(__entry->cb_how)
 		)
 );
+
+TRACE_EVENT(pnfs_ds_connect,
+		TP_PROTO(
+			char *ds_remotestr,
+			int status
+		),
+
+		TP_ARGS(ds_remotestr, status),
+
+		TP_STRUCT__entry(
+			__string(ds_ips, ds_remotestr)
+			__field(int, status)
+		),
+
+		TP_fast_assign(
+			__assign_str(ds_ips);
+			__entry->status = status;
+		),
+
+		TP_printk(
+			"ds_ips=%s, status=%d",
+			__get_str(ds_ips),
+			__entry->status
+                )
+);
+
 #endif /* CONFIG_NFS_V4_1 */
 
 TRACE_EVENT(nfs4_setup_sequence,
diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c
index 91ef486f40b9..4e25753945f6 100644
--- a/fs/nfs/pnfs_nfs.c
+++ b/fs/nfs/pnfs_nfs.c
@@ -17,6 +17,7 @@
 #include "internal.h"
 #include "pnfs.h"
 #include "netns.h"
+#include "nfs4trace.h"
 
 #define NFSDBG_FACILITY		NFSDBG_PNFS
 
@@ -998,8 +999,10 @@ int nfs4_pnfs_ds_connect(struct nfs_server *mds_srv, struct nfs4_pnfs_ds *ds,
 		err = nfs4_wait_ds_connect(ds);
 		if (err || ds->ds_clp)
 			goto out;
-		if (nfs4_test_deviceid_unavailable(devid))
-			return -ENODEV;
+		if (nfs4_test_deviceid_unavailable(devid)) {
+			err = -ENODEV;
+			goto out;
+		}
 	} while (test_and_set_bit(NFS4DS_CONNECTING, &ds->ds_state) != 0);
 
 	if (ds->ds_clp)
@@ -1029,11 +1032,12 @@ int nfs4_pnfs_ds_connect(struct nfs_server *mds_srv, struct nfs4_pnfs_ds *ds,
 		if (!ds->ds_clp || !nfs_client_init_is_complete(ds->ds_clp)) {
 			WARN_ON_ONCE(ds->ds_clp ||
 				!nfs4_test_deviceid_unavailable(devid));
-			return -EINVAL;
-		}
-		err = nfs_client_init_status(ds->ds_clp);
+			err = -EINVAL;
+		} else
+			err = nfs_client_init_status(ds->ds_clp);
 	}
 
+	trace_pnfs_ds_connect(ds->ds_remotestr, err);
 	return err;
 }
 EXPORT_SYMBOL_GPL(nfs4_pnfs_ds_connect);
-- 
2.49.0