From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Chris Mason <chris.mason@fusionio.com>,
Chris Mason <clmason@fusionio.com>,
Mikulas Patocka <mpatocka@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>, Jens Axboe <axboe@kernel.dk>,
Jeff Chua <jeff.chua.linux@gmail.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>, Jan Kara <jack@suse.cz>,
lkml <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH v2] Do a proper locking for mmap and block size change
Date: Fri, 30 Nov 2012 11:36:01 -0500 [thread overview]
Message-ID: <20121130163601.GA32238@infradead.org> (raw)
In-Reply-To: <20121130024910.GF6434@dastard>
On Fri, Nov 30, 2012 at 01:49:10PM +1100, Dave Chinner wrote:
> > Ugh. That's a big violation of how buffer-heads are supposed to work:
> > the block number is very much defined to be in multiples of b_size
> > (see for example "submit_bh()" that turns it into a sector number).
> >
> > But you're right. The direct-IO code really *is* violating that, and
> > knows that get_block() ends up being defined in i_blkbits regardless
> > of b_size.
>
> Same with mpage_readpages(), so it's not just direct IO that has
> this problem....
The mpage code may actually fall back to BHs.
I have a version of the direct I/O code that uses the iomap_ops from the
multi-page write code that you originally started. It uses the new op
as primary interface for direct I/O and provides a helper for
filesystems that still use buffer heads internally. I'll try to dust it
off and send out a version for the current kernel.
next prev parent reply other threads:[~2012-11-30 16:36 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-19 0:33 Recent kernel "mount" slow Jeff Chua
2012-11-20 18:09 ` Jan Kara
2012-11-21 15:46 ` Jeff Chua
2012-11-22 14:30 ` Jeff Chua
2012-11-22 19:21 ` Linus Torvalds
2012-11-23 13:24 ` Jens Axboe
2012-11-23 22:21 ` Jeff Chua
2012-11-23 23:31 ` Jeff Chua
2012-11-23 23:48 ` Jeff Chua
2012-11-24 21:09 ` Mikulas Patocka
2012-11-24 23:23 ` Jeff Chua
2012-11-27 5:57 ` Jeff Chua
2012-11-27 7:38 ` Jens Axboe
2012-11-27 7:44 ` Jens Axboe
2012-11-27 8:45 ` Jeff Chua
2012-11-27 10:06 ` Jeff Chua
2012-11-27 12:33 ` Jens Axboe
2012-11-28 3:57 ` Mikulas Patocka
2012-11-28 8:33 ` Jens Axboe
2012-11-28 13:05 ` Jeff Chua
2012-11-28 17:25 ` [PATCH] Introduce a method to catch mmap_region (was: Recent kernel "mount" slow) Mikulas Patocka
2012-11-28 19:15 ` Linus Torvalds
2012-11-28 19:43 ` Al Viro
2012-11-28 19:53 ` Linus Torvalds
2012-11-28 22:01 ` [PATCH v2] Do a proper locking for mmap and block size change Mikulas Patocka
2012-11-29 17:19 ` Linus Torvalds
2012-11-29 18:23 ` Mikulas Patocka
2012-11-29 18:46 ` Linus Torvalds
2012-11-29 19:02 ` Linus Torvalds
2012-11-29 19:15 ` Chris Mason
2012-11-29 19:26 ` Linus Torvalds
2012-11-29 19:48 ` Chris Mason
2012-11-29 19:55 ` Linus Torvalds
2012-11-29 20:10 ` Linus Torvalds
2012-11-29 20:52 ` Linus Torvalds
2012-11-29 21:29 ` Chris Mason
2012-11-29 22:16 ` Linus Torvalds
2012-11-29 22:36 ` Linus Torvalds
2012-11-30 1:16 ` Chris Mason
2012-11-30 2:13 ` Linus Torvalds
2012-11-30 2:27 ` Chris Mason
2012-11-30 2:49 ` Dave Chinner
2012-11-30 14:31 ` Chris Mason
2012-11-30 16:42 ` Linus Torvalds
2012-11-30 16:36 ` Christoph Hellwig [this message]
2012-11-30 22:40 ` Dave Chinner
2012-11-30 23:09 ` Christoph Hellwig
2012-11-29 19:50 ` Linus Torvalds
2012-11-28 19:50 ` [PATCH] Introduce a method to catch mmap_region (was: Recent kernel "mount" slow) Mikulas Patocka
2012-11-28 20:03 ` Linus Torvalds
2012-11-28 20:13 ` Linus Torvalds
2012-11-28 20:32 ` Linus Torvalds
2012-11-28 20:47 ` Linus Torvalds
2012-11-28 22:10 ` Mikulas Patocka
2012-11-28 21:29 ` Mikulas Patocka
2012-11-28 22:52 ` Linus Torvalds
2012-11-28 23:13 ` Linus Torvalds
2012-11-29 1:20 ` Mikulas Patocka
2012-11-29 0:38 ` Mikulas Patocka
2012-11-29 2:04 ` Linus Torvalds
2012-11-29 2:58 ` Linus Torvalds
2012-11-29 6:16 ` Linus Torvalds
2012-11-29 6:25 ` Al Viro
2012-11-29 6:30 ` Al Viro
2012-11-29 6:37 ` Linus Torvalds
2012-11-29 6:45 ` Al Viro
2012-11-29 10:57 ` Jeff Chua
2012-11-29 6:33 ` Linus Torvalds
2012-11-29 14:12 ` Chris Mason
2012-11-29 17:26 ` Chris Mason
2012-11-29 17:26 ` Linus Torvalds
2012-11-29 17:51 ` Chris Mason
2012-11-29 18:12 ` Linus Torvalds
2012-11-28 3:59 ` [PATCH 1/2] percpu-rwsem: use synchronize_sched_expedited Mikulas Patocka
2012-11-28 4:01 ` [PATCH 2/2] block_dev: don't take the write lock if block size doesn't change Mikulas Patocka
2012-11-28 14:24 ` Jeff Chua
2012-11-28 22:03 ` Mikulas Patocka
2012-11-28 14:19 ` [PATCH 1/2] percpu-rwsem: use synchronize_sched_expedited Jeff Chua
2012-11-30 0:06 ` Andrew Morton
2012-11-30 3:00 ` Mikulas Patocka
2012-11-30 13:42 ` Paul E. McKenney
2012-11-30 18:57 ` Oleg Nesterov
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