atime (Re: PATCH: prompt escape tests)

[Tanaka Akira <akr@jaist.ac.jp>]

In article <20000202105104.D31919@dan.emsphone.com>,
  Dan Nelson <dnelson@emsphone.com> writes:

> I think it's a POSIX requirement that atime must be updated.

Hm.

> Lots of unixes do let let you disable atime updates though (usually by
> mount -o noatime).  It's useful for news servers or FTP archives that
> do a lot of reading and don't really care about the atime field.  I
> looked on my Solaris 2.6 box and there doesn't seem to be a way to
> disable atime updates.  7 or 8 might very well be able to, though.

It's server side config and not related to this problem.

Linux produces NFS requests by `touch t':

02:26:54.406581 thorax.jaist.ac.jp.1258203975 > crane.nfs: 112 lookup fh 32,10/568960 "t" (ttl 62, id 8982)
02:26:54.408238 thorax.jaist.ac.jp.1258203976 > crane.nfs: 144 create fh 32,10/568960 "t" (ttl 62, id 8983)
02:26:54.437421 thorax.jaist.ac.jp.1258203977 > crane.nfs: 136 setattr fh 32,10/569010 (ttl 62, id 8986)

and by `cat t':

02:27:08.065326 thorax.jaist.ac.jp.1258203978 > crane.nfs: 112 lookup fh 32,10/568960 "t" (ttl 62, id 9002)
02:27:08.067635 thorax.jaist.ac.jp.1258203979 > crane.nfs: 104 getattr fh 32,10/569010 (ttl 62, id 9003)

Some requests (especialy requests by `cat t') are omitted by cache.
Anyway, the server cannot updates atime since the client doesn't send
read requests.
-- 
Tanaka Akira