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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Nick Piggin <npiggin@suse.de>
Cc: Andrew Morton <akpm@osdl.org>,
	Linux Memory Management <linux-mm@kvack.org>,
	Neil Brown <neilb@suse.de>, Anton Altaparmakov <aia21@cam.ac.uk>,
	Chris Mason <chris.mason@oracle.com>,
	Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [patch 6/6] mm: fix pagecache write deadlocks
Date: Sun, 15 Oct 2006 13:35:47 +0200	[thread overview]
Message-ID: <1160912147.5230.21.camel@lappy> (raw)
In-Reply-To: <20061014041927.GA14467@wotan.suse.de>

On Sat, 2006-10-14 at 06:19 +0200, Nick Piggin wrote:
> On Fri, Oct 13, 2006 at 03:14:57PM -0700, Andrew Morton wrote:
> > On Fri, 13 Oct 2006 18:44:52 +0200 (CEST)
> > Nick Piggin <npiggin@suse.de> wrote:

> > > @@ -2450,6 +2436,7 @@ int nobh_truncate_page(struct address_sp
> > >  		memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
> > >  		flush_dcache_page(page);
> > >  		kunmap_atomic(kaddr, KM_USER0);
> > > +		SetPageUptodate(page);
> > >  		set_page_dirty(page);
> > >  	}
> > >  	unlock_page(page);
> > 
> > I've already forgotten why this was added.  Comment, please ;)
> 
> Well, nobh_prepare_write no longer sets it uptodate, so we need to if
> we're going to set_page_dirty. OTOH, why does truncate_page need to
> zero the pagecache anyway? I wonder if we couldn't delete this whole
> function? (not in this patchset!)

It zeros the tail end of the page so we don't leak old data?

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  parent reply	other threads:[~2006-10-15 11:35 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-10-13 16:43 [rfc] buffered write deadlock fix Nick Piggin
2006-10-13 16:44 ` [patch 1/6] mm: revert "generic_file_buffered_write(): handle zero length iovec segments" Nick Piggin, Andrew Morton
2006-10-13 16:44 ` [patch 2/6] mm: revert "generic_file_buffered_write(): deadlock on vectored write" Nick Piggin, Andrew Morton
2006-10-13 16:44 ` [patch 3/6] mm: generic_file_buffered_write cleanup Nick Piggin, Andrew Morton
2006-10-13 16:44 ` [patch 4/6] mm: comment mmap_sem / lock_page lockorder Nick Piggin
2006-10-13 16:44 ` [patch 5/6] mm: debug write deadlocks Nick Piggin
2006-10-13 16:44 ` [patch 6/6] mm: fix pagecache " Nick Piggin, Andrew Morton
2006-10-13 22:14   ` Andrew Morton
2006-10-14  4:19     ` Nick Piggin
2006-10-14  4:30       ` Nick Piggin
2006-10-15 11:35       ` Peter Zijlstra [this message]
2006-10-14  5:04   ` Nick Piggin
2006-10-15 11:37   ` Peter Zijlstra
2006-10-15 11:56     ` Nick Piggin
2006-10-15 13:51       ` Peter Zijlstra
2006-10-15 14:19         ` SPAM: " Nick Piggin
2006-10-15 15:47           ` Peter Zijlstra
2006-10-15 15:57             ` RRe: " Nick Piggin
2006-10-15 16:13               ` Peter Zijlstra
2006-10-16 15:24                 ` pagefault_disable (was Re: [patch 6/6] mm: fix pagecache write deadlocks) Nick Piggin
2006-10-16 16:05                   ` Peter Zijlstra
2006-10-16 16:12                     ` Nick Piggin
2006-10-18 14:25   ` [patch 6/6] mm: fix pagecache write deadlocks Chris Mason

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