From: "J. Bruce Fields" <bfields@fieldses.org>
To: Jamie Lokier <jamie@shareable.org>
Cc: Volker Lendecke <Volker.Lendecke@SerNet.DE>,
linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
samba-technical@lists.samba.org,
Casey Bodley <cbodley@citi.umich.edu>
Subject: Re: [PATCH] locks: breaking read lease should not block read open
Date: Sun, 21 Aug 2011 12:50:29 -0400 [thread overview]
Message-ID: <20110821165029.GA9296@fieldses.org> (raw)
In-Reply-To: <20110819190829.GD11512@jl-vm1.vm.bytemark.co.uk>
On Fri, Aug 19, 2011 at 08:08:29PM +0100, Jamie Lokier wrote:
> J. Bruce Fields wrote:
> > I'm not sure how to approach the lease code.
> >
> > On the one hand, I've never seen any evidence that anyone outside Samba
> > and NFSv4 has ever used it, and both currently make extremely limited
> > use of it. So we could probably get away with "fixing" the lease code
> > to do whatever both of us need.
>
> I've never used it, but I've _nearly_ used it (project took a
> different direction), in a web application framework.
>
> Pretty much the way CIFS/NFS use it, to keep other things (remote
> state, database state, derived files) transactionally coherent with
> changes to file contents by programs that only know about the files
> they access.
>
> The SIGIO stuff is a horrible interface.
> I could still see me trying to use it sometime in the future.
> In which case I really don't mind if you make the semantics saner :-)
>
> Now we have fanotify which does something very similar and could have
> generalised leases, but unfortunately fanotify came from such a
> different motivation that it's not well suited for ordinary user
> applications.
I'm not sure what you mean by that--mainly just because I'm not as
familiar with fanotify as I should be.
For my case the important difference between leases and the various
notification interfaces is that leases are synchronous--the lease-holder
is notified and has a chance to clean up before releasing its lease and
allowing the conflicting operation to continue--whereas the the various
notification interfaces tell you "tough luck, something just happened".
--b.
next prev parent reply other threads:[~2011-08-21 16:50 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-09 23:16 [PATCH] locks: breaking read lease should not block read open J. Bruce Fields
2011-06-10 7:56 ` Volker Lendecke
2011-06-10 13:48 ` J. Bruce Fields
2011-07-21 0:07 ` J. Bruce Fields
2011-07-21 0:15 ` Jeremy Allison
2011-07-21 16:35 ` J. Bruce Fields
2011-07-29 2:27 ` J. Bruce Fields
2011-07-29 2:29 ` [PATCH 1/3] locks: minor lease cleanup J. Bruce Fields
2011-07-29 2:29 ` [PATCH 2/3] locks: move F_INPROGRESS from fl_type to fl_flags field J. Bruce Fields
2011-07-29 2:30 ` [PATCH 3/3] locks: fix tracking of inprogress lease breaks J. Bruce Fields
2011-08-19 16:04 ` [PATCH] locks: breaking read lease should not block read open J. Bruce Fields
2011-08-19 16:07 ` [PATCH 1/4] locks: minor lease cleanup J. Bruce Fields
2011-08-19 16:07 ` [PATCH 2/4] locks: move F_INPROGRESS from fl_type to fl_flags field J. Bruce Fields
2011-08-19 16:07 ` [PATCH 3/4] locks: fix tracking of inprogress lease breaks J. Bruce Fields
2011-08-19 16:07 ` [PATCH 4/4] locks: setlease cleanup J. Bruce Fields
2011-08-19 19:08 ` [PATCH] locks: breaking read lease should not block read open Jamie Lokier
2011-08-21 16:50 ` J. Bruce Fields [this message]
2011-11-21 12:46 ` Jamie Lokier
2011-11-22 21:44 ` J. Bruce Fields
2011-11-23 0:30 ` Jamie Lokier
2011-11-23 19:08 ` J. Bruce Fields
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20110821165029.GA9296@fieldses.org \
--to=bfields@fieldses.org \
--cc=Volker.Lendecke@SerNet.DE \
--cc=cbodley@citi.umich.edu \
--cc=jamie@shareable.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-nfs@vger.kernel.org \
--cc=samba-technical@lists.samba.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).