From: "J. Bruce Fields" <bfields@fieldses.org>
To: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
samba-technical@lists.samba.org,
Christoph Hellwig <hch@infradead.org>,
Eric Paris <eparis@redhat.com>
Subject: Re: [PATCH 1/2] locks: introduce i_blockleases to close lease races
Date: Mon, 13 Jun 2011 20:35:53 -0400 [thread overview]
Message-ID: <20110614003553.GA24557@fieldses.org> (raw)
In-Reply-To: <1307997423.13410.63.camel@localhost.localdomain>
On Mon, Jun 13, 2011 at 04:37:03PM -0400, Mimi Zohar wrote:
> On Mon, 2011-06-13 at 08:19 -0400, J. Bruce Fields wrote:
> > On Sun, Jun 12, 2011 at 04:54:33PM -0400, Mimi Zohar wrote:
> > > On Sun, 2011-06-12 at 15:12 -0400, J. Bruce Fields wrote:
> > > > On Sun, Jun 12, 2011 at 03:10:04PM -0400, Mimi Zohar wrote:
> > > > > In lieu of adding a new inode field, another possible option, a bit
> > > > > kludgy, would be extending i_flock with an additional fl_flag
> > > > > FL_BLOCKLEASE.
> > > > >
> > > > > #define IS_BLOCKLEASE(fl) (fl->fl_flags & FL_BLOCKLEASE)
> > > >
> > > > Alas, that would mean adding and removing one of these file locks around
> > > > every single link, unlink, rename,....
> > > >
> > > > --b.
> > >
> > > You're adding a call to break_lease() for each of them. Currently
> > > __break_lease() is only called if a lease exists. Assuming there aren't
> > > any existing leases, couldn't break_lease() call something like
> > > block_lease()? The free would be after the link, unlink, ...,
> > > completed/failed.
> > >
> > > (You wouldn't actually need to alloc/free the 'struct file_lock' each
> > > time, just set the pointer and reset to NULL.)
> >
> > Well, the pointer has to be set to something. I suppose we could put a
> > struct file_lock on the stack.
> >
> > --b.
>
> Instead of putting the struct file_lock on the stack, how about creating
> a dummy list containing a single element with FL_BLOCKLEASE set?
I'm afraid I don't understand what you're proposing. Could you explain
in more detail?
--b.
next prev parent reply other threads:[~2011-06-14 0:35 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-10 0:09 lease/delegation/oplock semantics J. Bruce Fields
2011-06-10 0:10 ` [PATCH 1/2] locks: introduce i_blockleases to close lease races J. Bruce Fields
[not found] ` <20110610001011.GD22215-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2011-06-10 0:11 ` [PATCH 2/2] locks: break lease on unlink J. Bruce Fields
2011-06-10 20:24 ` [PATCH 1/2] locks: introduce i_blockleases to close lease races Mimi Zohar
2011-06-10 21:34 ` J. Bruce Fields
2011-06-12 4:08 ` J. Bruce Fields
2011-06-12 19:10 ` Mimi Zohar
2011-06-12 19:12 ` J. Bruce Fields
[not found] ` <20110612191220.GK12149-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2011-06-12 20:54 ` Mimi Zohar
2011-06-13 12:19 ` J. Bruce Fields
2011-06-13 20:37 ` Mimi Zohar
2011-06-14 0:35 ` J. Bruce Fields [this message]
[not found] ` <20110613121939.GL12149-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2011-06-15 15:47 ` J. Bruce Fields
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