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From: Andrew Morton <akpm@osdl.org>
To: Jens Axboe <axboe@suse.de>
Cc: linux-kernel@vger.kernel.org, torvalds@osdl.org
Subject: Re: [PATCH][RFC] splice support
Date: Thu, 30 Mar 2006 01:56:30 -0800	[thread overview]
Message-ID: <20060330015630.00d8cba2.akpm@osdl.org> (raw)
In-Reply-To: <20060330094522.GR13476@suse.de>

Jens Axboe <axboe@suse.de> wrote:
>
> > The one-at-a-time logic looks OK from a quick scan.  Do we have logic in
>  > there to check that we're not overrunning i_size?  (See the pain
>  > do_generic_mapping_read() goes through).
> 
>  do_splice_to() checks that, should I move that checking further down in
>  case the file is truncated?

Again, see do_generic_mapping_read()'s ghastly tricks - it checks i_size
after each readpage().

i_size can increase or decrease under our feet if we're not holding i_mutex
(and we don't want to).  So userspace is being silly and the main things we
need to care about here are to not leak uninitialised data and to not oops.
A readpage() outside i_size will return either all-zeroes or some valid
data which isn't actually within i_size any more, so I guess we're OK.




  reply	other threads:[~2006-03-30  9:56 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-03-29 12:28 Jens Axboe
2006-03-29 12:30 ` Jens Axboe
2006-03-29 13:15 ` Jeff Garzik
2006-03-29 13:27   ` Jens Axboe
2006-03-29 21:49     ` Nathan Scott
2006-03-29 20:06   ` Linus Torvalds
2006-03-29 20:42     ` Jens Axboe
2006-03-29 20:43       ` Jens Axboe
2006-03-29 21:14         ` Linus Torvalds
2006-03-30  6:17           ` Jens Axboe
2006-03-29 22:37 ` Andrew Morton
2006-03-30  0:50   ` Linus Torvalds
2006-03-30  1:04     ` Jeff Garzik
2006-03-30  1:20       ` Andrew Morton
2006-03-30  6:18         ` Jens Axboe
2006-03-30  2:08     ` Andrew Morton
2006-03-30  3:44       ` Nick Piggin
2006-03-30  7:21       ` Jens Axboe
2006-03-30  7:30         ` Andrew Morton
2006-03-30  7:33           ` Jens Axboe
2006-03-30  8:02             ` Jan Engelhardt
2006-03-30  3:10     ` Nick Piggin
2006-03-30  7:16     ` Jens Axboe
2006-03-30  8:09     ` Jan Engelhardt
2006-03-30  7:45   ` Jens Axboe
2006-03-30  8:02     ` Andrew Morton
2006-03-30  8:10       ` Jens Axboe
2006-03-30  8:25         ` Nick Piggin
2006-03-30  8:27         ` Andrew Morton
2006-03-30  8:50           ` Nick Piggin
2006-03-30  8:51           ` Jens Axboe
2006-03-30  9:15             ` Jens Axboe
2006-03-30  9:40               ` Andrew Morton
2006-03-30  9:45                 ` Jens Axboe
2006-03-30  9:56                   ` Andrew Morton [this message]
2006-03-30 10:01                     ` Jens Axboe
2006-03-30  2:36 ` Nick Piggin
2006-03-30  7:00   ` Jens Axboe
2006-03-30  7:33     ` Nick Piggin
2006-03-30  8:54 ` KAMEZAWA Hiroyuki
2006-03-30 13:53   ` Jens Axboe
2006-03-30 14:05     ` KAMEZAWA Hiroyuki
2006-03-30 14:38       ` Jens Axboe
2006-03-30 14:55         ` KAMEZAWA Hiroyuki
  -- strict thread matches above, loose matches on Subject: below --
2005-12-19  9:16 Jens Axboe

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