From d983803d3818a7aef3200147c72a45f573d84537 Mon Sep 17 00:00:00 2001
From: Peng Tao <tao.peng@primarydata.com>
Date: Tue, 23 Jun 2015 19:52:00 +0800
Subject: pNFS/flexfiles: track when layout is first used

So that we can report cumulative time since the beginning
of statistics collection of the layout.

Reviewed-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
index 8ac31fb..4215278 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.c
+++ b/fs/nfs/flexfilelayout/flexfilelayout.c
@@ -451,9 +451,13 @@ nfs4_ff_layout_calc_completion_time(struct rpc_task *task)
 }
 
 static void
-nfs4_ff_layoutstat_start_io(struct nfs4_ff_layoutstat *layoutstat)
+nfs4_ff_layoutstat_start_io(struct nfs4_ff_layout_mirror *mirror,
+			    struct nfs4_ff_layoutstat *layoutstat)
 {
+	static const ktime_t notime = {0};
+
 	nfs4_ff_start_busy_timer(&layoutstat->busy_timer);
+	cmpxchg(&mirror->start_time, notime, ktime_get());
 }
 
 static void
@@ -491,7 +495,7 @@ nfs4_ff_layout_stat_io_start_read(struct nfs4_ff_layout_mirror *mirror,
 		__u64 requested)
 {
 	spin_lock(&mirror->lock);
-	nfs4_ff_layoutstat_start_io(&mirror->read_stat);
+	nfs4_ff_layoutstat_start_io(mirror, &mirror->read_stat);
 	nfs4_ff_layout_stat_io_update_requested(&mirror->read_stat, requested);
 	spin_unlock(&mirror->lock);
 }
@@ -514,7 +518,7 @@ nfs4_ff_layout_stat_io_start_write(struct nfs4_ff_layout_mirror *mirror,
 		__u64 requested)
 {
 	spin_lock(&mirror->lock);
-	nfs4_ff_layoutstat_start_io(&mirror->write_stat);
+	nfs4_ff_layoutstat_start_io(mirror, &mirror->write_stat);
 	nfs4_ff_layout_stat_io_update_requested(&mirror->write_stat, requested);
 	spin_unlock(&mirror->lock);
 }
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.h b/fs/nfs/flexfilelayout/flexfilelayout.h
index f7493f7..0e7366f 100644
--- a/fs/nfs/flexfilelayout/flexfilelayout.h
+++ b/fs/nfs/flexfilelayout/flexfilelayout.h
@@ -74,6 +74,7 @@ struct nfs4_ff_layout_mirror {
 	spinlock_t			lock;
 	struct nfs4_ff_layoutstat	read_stat;
 	struct nfs4_ff_layoutstat	write_stat;
+	ktime_t				start_time;
 };
 
 struct nfs4_ff_layout_segment {
-- 
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