From: Chris Mason <chris.mason@oracle.com>
To: David Woodhouse <dwmw2@infradead.org>
Cc: David Howells <dhowells@redhat.com>, David Chinner <dgc@sgi.com>,
lkml <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH 1 of 2] block_page_mkwrite() Implementation V2
Date: Wed, 16 May 2007 08:53:41 -0400 [thread overview]
Message-ID: <20070516125341.GS26766@think.oraclecorp.com> (raw)
In-Reply-To: <1179317360.2859.225.camel@shinybook.infradead.org>
On Wed, May 16, 2007 at 08:09:19PM +0800, David Woodhouse wrote:
> On Wed, 2007-05-16 at 11:19 +0100, David Howells wrote:
> > The start and end points passed to block_prepare_write() delimit the region of
> > the page that is going to be modified. This means that prepare_write()
> > doesn't need to fill it in if the page is not up to date.
>
> Really? Is it _really_ going to be modified? Even if the pointer
> userspace gave to write() is bogus, and is going to fault half-way
> through the copy_from_user()?
This is why there are so many variations on copy_from_user that zero on
faults. One way or another, the prepare_write/commit_write pair are
responsible for filling it in.
-chris
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next prev parent reply other threads:[~2007-05-16 12:53 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-18 23:30 David Chinner
2007-03-19 6:37 ` Nick Piggin
2007-03-19 8:12 ` David Chinner
2007-03-19 9:57 ` Nick Piggin
2007-03-19 10:28 ` Nick Piggin
2007-03-19 9:22 ` Christoph Hellwig
2007-03-19 10:11 ` Nick Piggin
2007-03-19 12:22 ` Christoph Hellwig
2007-03-20 5:34 ` Nick Piggin
2007-05-16 10:19 ` David Howells
2007-05-16 11:59 ` Nick Piggin
2007-05-16 12:09 ` David Woodhouse
2007-05-16 12:53 ` Chris Mason [this message]
2007-05-16 13:04 ` Nick Piggin
2007-05-16 13:10 ` Chris Mason
2007-05-16 13:20 ` David Howells
2007-05-16 13:41 ` Nick Piggin
2007-05-16 13:25 ` David Howells
2007-05-16 23:28 ` David Chinner
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