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From: Andrew Morton <akpm@linux-foundation.org>
To: Nick Piggin <npiggin@suse.de>
Cc: Linux Filesystems <linux-fsdevel@vger.kernel.org>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [rfc][patch 0/3] a faster buffered write deadlock fix?
Date: Fri, 9 Feb 2007 02:09:54 -0800	[thread overview]
Message-ID: <20070209020954.4951256e.akpm@linux-foundation.org> (raw)
In-Reply-To: <20070209095405.GA14398@wotan.suse.de>

On Fri, 9 Feb 2007 10:54:05 +0100 Nick Piggin <npiggin@suse.de> wrote:

> On Fri, Feb 09, 2007 at 12:41:01AM -0800, Andrew Morton wrote:
> > On Thu,  8 Feb 2007 14:07:15 +0100 (CET) Nick Piggin <npiggin@suse.de> wrote:
> > 
> > > So I have finally finished a first slightly-working draft of my new aops
> > > op (perform_write) proposal. I would be interested to hear comments about
> > > it.  Most of my issues and concerns are in the patch headers themselves,
> > > so reply to them.
> > > 
> > > The patches are against my latest buffered-write-fix patchset.
> > 
> > What happened with Linus's proposal to instantiate the page as pinned,
> > non-uptodate, unlocked and in pagecache while we poke the user address?
> 
> That's still got a deadlock,

It does?

>  and also it doesn't work if we want to lock
> the page when performing a minor fault (which I want to fix fault vs
> invalidate),

It's hard to discuss this without a description of what you want to fix
there, and a description of how you plan to fix it.

> and also assumes nobody's ->nopage locks the page or
> requires any resources that are held by prepare_write (something not
> immediately clear to me with the cluster filesystems, at least).

The nopage handler is filemap_nopage().  Are there any exceptions to that?

> But that all becomes legacy path, so do we really care? Supposing fs
> maintainers like perform_write, then after the main ones have implementations
> we could switch over to the slow-but-correct prepare_write legacy path.
> Or we could leave it, or we could use Linus's slightly-less-buggy scheme...
> by that point I expect I'd be sick of arguing about it ;)

It's worth "arguing" about.  This is write().  What matters more??

  reply	other threads:[~2007-02-09 10:10 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-08 13:07 Nick Piggin
2007-02-08 13:07 ` [patch 1/3] fs: add an iovec iterator Nick Piggin
2007-02-08 19:49   ` Christoph Hellwig
2007-02-09  1:46     ` Nick Piggin
2007-02-09  2:03       ` Nate Diller
2007-02-09  3:31         ` Nick Piggin
2007-02-09 17:28           ` Zach Brown
2007-03-09 10:40         ` Christoph Hellwig
2007-02-08 23:04   ` Mark Fasheh
2007-02-08 13:07 ` [patch 2/3] fs: introduce perform_write aop Nick Piggin
2007-03-09 10:39   ` Christoph Hellwig
2007-03-09 12:52     ` Nick Piggin
2007-03-09 22:01       ` Anton Altaparmakov
2007-03-09 23:33     ` Mark Fasheh
2007-03-10  9:25       ` Christoph Hellwig
2007-03-12  2:13         ` Mark Fasheh
2007-03-14 13:30         ` Nick Piggin
2007-03-14 15:17           ` Christoph Hellwig
2007-02-08 13:07 ` [patch 3/3] ext2: use " Nick Piggin
2007-02-08 14:47   ` Dmitriy Monakhov
2007-02-09 19:14   ` Andrew Morton
2007-02-09 19:45     ` Andrew Morton
2007-02-10  1:34       ` Nick Piggin
2007-02-10  1:50         ` Andrew Morton
2007-02-09  0:38 ` [rfc][patch 0/3] a faster buffered write deadlock fix? Mark Fasheh
2007-02-09  2:04   ` Nick Piggin
2007-02-09  8:41 ` Andrew Morton
2007-02-09  9:54   ` Nick Piggin
2007-02-09 10:09     ` Andrew Morton [this message]
2007-02-09 10:32       ` Nick Piggin
2007-02-09 10:52         ` Andrew Morton
2007-02-09 11:31           ` Nick Piggin
2007-02-09 11:46             ` Andrew Morton
2007-02-09 12:11               ` Nick Piggin

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