Signed-off-by: sickamd@gmail.com
---
 fs/inode.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index da85e56..6c8effd 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1469,7 +1469,13 @@ static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
 		return 1;
 
 	/*
-	 * Is the previous atime value older than a day? If yes,
+	 * Is the previous atime value in future? If yes,
+	 * update atime:
+	 */
+	if ((long)(now.tv_sec - inode->i_atime.tv_sec) < 0)
+		return 1;
+	/*
+	 * Is the previous atime value old than a day? If yes,
 	 * update atime:
 	 */
 	if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
-- 
1.7.2.3

--

[ message continues ]

Why do you believe this change is needed?  Did you observe some problem
which it fixes?  If so, please fully describe that problem.

--

[ message continues ]

If atime has been set to future(maybe cause by some accident system time 
adjust or wrong set by touch). It cannot be update to reflect fact 
access time before system time running over one day.

Thanks



--

[ message continues ]

You introduced a typo. 

	Roger. 

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--

[ message continues ]

Hi,


I don't think this is a good plan for cluster filesystems, since if the
times on the nodes are not exactly synchronised (we do highly recommend
people run ntp or similar) then this might lead to excessive atime
updating. The current behaviour is to ignore atimes which are in the
future for exactly this reason,

Steve.


--

[ message continues ]

The problem that is seen is if a tarball has stored a bad atime, or someone fat-fingers a "touch" then the future atime will never be fixed. Before the relatime patch, the future atime would be updated back to the current time on the next access. One if our regression tests for Lustre caught this. 

I wouldn't mind changing the relatime check so that it only updates the atime if it is more than one day in the future. That will avoid thrashing atime if the clocks are only slightly out of sync, but still allow fixing completely bogus atimes. 

Cheers, Andreas--

[ message continues ]

I agreed in theory.  Anyway, a two-way update may cause shake in some 
case. Like a cluster environment with time gap between cluster members. 
But future atime also is a trouble things i think. Of course, I hope a 
clever patch to fix them all.

Thanks
yangsheng
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[ message continues ]