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From: Andrew Morton <akpm@linux-foundation.org>
To: Hugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org
Subject: Re: [PATCH] mm for fs: add truncate_pagecache_range
Date: Fri, 23 Mar 2012 15:59:50 -0700	[thread overview]
Message-ID: <20120323155950.f9bfb097.akpm@linux-foundation.org> (raw)
In-Reply-To: <alpine.LSU.2.00.1203231406090.2207@eggly.anvils>

On Fri, 23 Mar 2012 14:14:54 -0700 (PDT)
Hugh Dickins <hughd@google.com> wrote:

> On Fri, 23 Mar 2012, Andrew Morton wrote:
> > 
> > --- a/mm/truncate.c~mm-for-fs-add-truncate_pagecache_range-fix
> > +++ a/mm/truncate.c
> > @@ -639,6 +639,9 @@ int vmtruncate_range(struct inode *inode
> >   * with on-disk format, and the filesystem would not have to deal with
> >   * situations such as writepage being called for a page that has already
> >   * had its underlying blocks deallocated.
> > + *
> > + * Must be called with inode->i_mapping->i_mutex held.
> 
> You catch me offguard: I forget whether that's an absolute requirement or
> just commonly the case.  What do the other interfaces in truncate.c say ?-)

i_mutex is generally required, to stabilise i_size.

> > + * Takes inode->i_mapping->i_mmap_mutex.
> 
> Yes, and inode->i_mapping->tree_lock.

I don't think it's necessary to get into the spinning locks for a
high-level function which clearly does sleeping things.


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  reply	other threads:[~2012-03-23 22:59 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-23 20:46 [PATCH] mm for fs: add truncate_pagecache_range Hugh Dickins
2012-03-23 21:01 ` Andrew Morton
2012-03-23 21:14   ` Hugh Dickins
2012-03-23 22:59     ` Andrew Morton [this message]
2012-03-25 20:26       ` Hugh Dickins
2012-03-25 20:50         ` Andrew Morton
2012-03-25 21:55           ` Hugh Dickins
2012-04-03  5:45         ` Joel Becker
2012-05-13 21:03 ` Hugh Dickins
2012-05-17  9:25   ` Joel Becker

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