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From: Jeff Layton <jeff.layton@primarydata.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org,
	"J. Bruce Fields" <bfields@fieldses.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 05/17] locks: generic_delete_lease doesn't need a file_lock at all
Date: Thu, 4 Sep 2014 20:29:26 -0400	[thread overview]
Message-ID: <20140904202926.74c76ee2@tlielax.poochiereds.net> (raw)
In-Reply-To: <20140904201424.GB26054@infradead.org>

On Thu, 4 Sep 2014 13:14:24 -0700
Christoph Hellwig <hch@infradead.org> wrote:

> On Thu, Sep 04, 2014 at 08:38:31AM -0400, Jeff Layton wrote:
> > Ensure that it's OK to pass in a NULL file_lock double pointer on
> > a F_UNLCK request and convert the vfs_setlease F_UNLCK callers to
> > do just that.
> > 
> > Finally, turn the BUG_ON in generic_setlease into a WARN_ON_ONCE
> > with an error return. That's a problem we can handle without
> > crashing the box if it occurs.
> 
> Can we just make generic_delete_lease (maye renamed to vfs_delete_lease)
> the interface for deleting leases instead of going through a useless
> multiplex and file operation?
> 

I'm not sure that change really makes sense to me at this point.

Suppose we have an exportable filesystem with a ->setlease
implementation [1]. We end up calling into it to set up a lease and it
calls generic_add_lease. If we make the change you're suggesting, then
we'll have no parallel to a ->setlease op when removing that lease.

We could of course make a ->dellease op or something, but I'd rather
not introduce that change until I've had a chance to do some other
cleanup to the file locking infrastructure.

So...I'm not opposed to doing what you suggest, but I'd rather not do it
just yet until I've gotten a little farther with some other cleanup of
how we deal with locks in general. I think it'll be easier to do that
once some other changes have gone in.

I'll post a draft patchset based on those changes "real soon now" as an
RFC. Hopefully at that point my rationale will make a bit more sense...

[1]: of course, only cifs has a non-trivial one for now and it's pretty
half-assed...

-- 
Jeff Layton <jlayton@primarydata.com>

  reply	other threads:[~2014-09-05  0:29 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-04 12:38 [PATCH v2 00/17] locks: internal lease API overhaul Jeff Layton
2014-09-04 12:38 ` [PATCH v2 01/17] locks: consolidate "nolease" routines Jeff Layton
2014-09-04 12:41   ` Trond Myklebust
2014-09-04 12:49     ` Jeff Layton
2014-09-04 18:25       ` Trond Myklebust
2014-09-04 20:12         ` Christoph Hellwig
2014-09-05 11:48           ` Jeff Layton
2014-09-04 17:46   ` Christoph Hellwig
2014-09-04 12:38 ` [PATCH v2 02/17] security: make security_file_set_fowner, f_setown and __f_setown void return Jeff Layton
2014-09-04 17:47   ` Christoph Hellwig
2014-10-07 17:11   ` Dmitry Kasatkin
2014-10-07 17:17     ` Christoph Hellwig
2014-10-07 17:34       ` Dmitry Kasatkin
2014-10-07 18:02         ` Jeff Layton
2014-09-04 12:38 ` [PATCH v2 03/17] locks: close potential race in lease_get_mtime Jeff Layton
2014-09-04 12:38 ` [PATCH v2 04/17] nfsd: fix potential lease memory leak in nfs4_setlease Jeff Layton
2014-09-04 12:38 ` [PATCH v2 05/17] locks: generic_delete_lease doesn't need a file_lock at all Jeff Layton
2014-09-04 20:14   ` Christoph Hellwig
2014-09-05  0:29     ` Jeff Layton [this message]
2015-01-12 23:03   ` NeilBrown
2015-01-12 23:25     ` Jeff Layton
2015-01-13  2:14       ` NeilBrown
2014-09-04 12:38 ` [PATCH v2 06/17] locks: clean up vfs_setlease kerneldoc comments Jeff Layton
2014-09-04 12:38 ` [PATCH v2 07/17] nfsd: don't keep a pointer to the lease in nfs4_file Jeff Layton
2014-09-05 21:40   ` J. Bruce Fields
2014-09-06 12:33     ` Jeff Layton
2014-09-04 12:38 ` [PATCH v2 08/17] locks: plumb a "priv" pointer into the setlease routines Jeff Layton
2014-09-04 17:48   ` Christoph Hellwig
2014-09-04 12:38 ` [PATCH v2 09/17] locks: define a lm_setup handler for leases Jeff Layton
2014-09-04 17:49   ` Christoph Hellwig
2014-09-04 12:38 ` [PATCH v2 10/17] locks: move i_lock acquisition into generic_*_lease handlers Jeff Layton
2014-09-04 12:38 ` [PATCH v2 11/17] locks: move freeing of leases outside of i_lock Jeff Layton
2014-09-04 17:50   ` Christoph Hellwig
2014-09-05 14:03     ` Jeff Layton
2014-09-04 12:38 ` [PATCH v2 12/17] locks: update Documentation/filesystems with new setlease semantics Jeff Layton
2014-09-04 17:50   ` Christoph Hellwig
2014-09-05 14:02     ` Jeff Layton
2014-09-04 12:38 ` [PATCH v2 13/17] locks: remove i_have_this_lease check from __break_lease Jeff Layton
2014-09-04 17:51   ` Christoph Hellwig
2014-09-04 18:03     ` Jeff Layton
2014-09-04 12:38 ` [PATCH v2 14/17] locks: __break_lease cleanup in preparation of allowing direct removal of leases Jeff Layton
2014-09-04 18:07   ` Christoph Hellwig
2014-09-05 13:35     ` Jeff Layton
2014-09-04 12:38 ` [PATCH v2 15/17] locks: give lm_break a return value Jeff Layton
2014-09-04 18:08   ` Christoph Hellwig
2014-09-04 12:38 ` [PATCH v2 16/17] locks: set fl_owner for leases to filp instead of current->files Jeff Layton
2014-09-04 12:38 ` [PATCH v2 17/17] locks: clean up comments over fl_owner_t definition Jeff Layton
2014-09-04 17:53   ` Christoph Hellwig
2014-09-05 13:36     ` Jeff Layton

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