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From: NeilBrown <neilb@suse.de>
To: "J. Bruce Fields" <bfields@fieldses.org>,
	Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: linux-nfs@vger.kernel.org
Subject: [PATCH 0/2] sunrpc: use monotonic time for expiry times
Date: Wed, 17 Feb 2010 17:47:30 +1100	[thread overview]
Message-ID: <20100217064330.13656.61404.stgit@notabene.brown> (raw)

I've always known I would pay for this some day ....

The authentication cache uses wall-clock time for expiry times and
related time stamps.

This can cause problems if the wall-clock time changes suddenly.
e.g. if you set the time forward one hour, the export cache is
immediately flushed.  This isn't an enormous problem, but it should be
fixed.

Currently, it can cause clients to have to resend requests which can
cause a delay of several timeouts.  Once we get the improvements in
which allow a thread to wait for a while rather than dropping a
request, this will be less of an issue.  But I think it is worth
fixing anyway.

So: two patches.  One moves come common code to an inline, the other
makes the change.

comments?

Thanks,
NeilBrown

---

NeilBrown (2):
      sunrpc: extract some common sunrpc_cache code from nfsd
      sunrpc: use monotonic time in expiry cache


 fs/nfs/dns_resolve.c         |    6 +++---
 fs/nfsd/export.c             |    9 +++------
 fs/nfsd/nfs4idmap.c          |    2 +-
 include/linux/sunrpc/cache.h |   23 ++++++++++++++++++++++-
 net/sunrpc/cache.c           |   33 ++++++++++++++++++---------------
 5 files changed, 47 insertions(+), 26 deletions(-)



             reply	other threads:[~2010-02-17  6:48 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-17  6:47 NeilBrown [this message]
     [not found] ` <20100217064330.13656.61404.stgit-wvvUuzkyo1EYVZTmpyfIwg@public.gmane.org>
2010-02-17  6:47   ` [PATCH 1/2] sunrpc: extract some common sunrpc_cache code from nfsd NeilBrown
2010-02-17  6:47   ` [PATCH 2/2] sunrpc: use monotonic time in expiry cache NeilBrown
     [not found]     ` <20100217064730.13656.67205.stgit-wvvUuzkyo1EYVZTmpyfIwg@public.gmane.org>
2010-02-17 22:00       ` Chuck Lever
2010-03-02  4:11         ` Neil Brown

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