From: Dave Kleikamp <dave.kleikamp@oracle.com>
To: Christoph Hellwig <hch@infradead.org>, Al Viro <viro@ZenIV.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>, Sage Weil <sage@inktank.com>,
Mark Fasheh <mfasheh@suse.com>,
xfs@oss.sgi.com, Steve French <sfrench@samba.org>,
Kent Overstreet <kmo@daterainc.com>,
Joel Becker <jlbec@evilplan.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Anton Altaparmakov <anton@tuxera.com>
Subject: Re: [RFC] unifying write variants for filesystems
Date: Mon, 03 Feb 2014 10:50:02 -0600 [thread overview]
Message-ID: <52EFC8BA.3010906@oracle.com> (raw)
In-Reply-To: <20140203151242.GA6868@infradead.org>
On 02/03/2014 09:12 AM, Christoph Hellwig wrote:
> On Sat, Feb 01, 2014 at 10:43:01PM +0000, Al Viro wrote:
>> * WTF bother passing 'pos' separately? It's the same mistake that was
>> made with ->aio_read/->aio_write and just as with those, *all* callers
>> provably have pos == iocb->ki_pos.
>
> I think this landed with the initial aio support, which planned for
> allowing AIO retries for a workqueue with a partially incremented
> pos. None of this ever got merged, probably because it was too ugly
> to live.
Yeah, when these patches were first written, AIO looked a lot different.
>> * We *definitely* want a variant structure with tag - unsigned long thing
>> was just plain insane. I see at least two variants - array of iovecs
>> and array of (at least) triples <page, offset, length>. Quite possibly -
>> quadruples, with "here's how to try to steal this page" thrown in, if
>> we want that as replacement for ->splice_write() as well (it looks like
>> the few instances that do steal on pipe-to-file splices could be dealt
>> with the same way as the dumb ones, provided that ->write_iter or whatever
>> we end up calling it is allowed to try and steal pages). Possibly more
>> variants on the read side of things... FWIW, I'm not sure that bio_vec
>> makes a lot of sense here.
>
> bio_vec just is one of the many page+offset+len containers we have, I
> guess Dave took it because loop uses it. We could either invent a new
> one here or finally have a common one for the different uses all over
> the kernel.
With Kent's immutable bio_vec changes, peeking inside the bio to get to
the bio_vec is uglier than it was before, so there's no need to stick
with that.
Shaggy
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next prev parent reply other threads:[~2014-02-03 16:50 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-12 18:14 [PATCH 0/5] splice: locking changes and code refactoring Christoph Hellwig
2013-12-12 18:15 ` [PATCH 1/5] splice: move balance_dirty_pages_ratelimited into pipe_to_file Christoph Hellwig
2013-12-12 18:15 ` [PATCH 2/5] splice: nest i_mutex outside pipe_lock Christoph Hellwig
2013-12-12 18:15 ` [PATCH 3/5] splice: use splice_from_pipe in generic_file_splice_write Christoph Hellwig
2013-12-12 18:15 ` [PATCH 4/5] xfs: fix splice_write locking Christoph Hellwig
2013-12-12 18:15 ` [PATCH 5/5] splice: stop exporting splice_from_pipe implementation details Christoph Hellwig
2014-01-13 14:14 ` [PATCH 0/5] splice: locking changes and code refactoring Christoph Hellwig
2014-01-13 23:56 ` Al Viro
2014-01-14 13:22 ` Christoph Hellwig
2014-01-14 17:20 ` Al Viro
2014-01-15 18:10 ` Al Viro
2014-01-18 6:40 ` Al Viro
2014-01-18 7:22 ` Linus Torvalds
2014-01-18 7:46 ` Al Viro
2014-01-18 7:56 ` Al Viro
2014-01-18 8:27 ` Al Viro
2014-01-18 8:44 ` David Miller
2014-02-07 17:10 ` Al Viro
2014-01-18 19:59 ` Linus Torvalds
2014-01-18 20:10 ` Al Viro
2014-01-18 20:27 ` Al Viro
2014-01-18 20:30 ` Al Viro
2014-01-19 5:13 ` [RFC] unifying write variants for filesystems Al Viro
2014-01-20 13:55 ` Christoph Hellwig
2014-01-20 20:32 ` Linus Torvalds
2014-02-01 22:43 ` Al Viro
2014-02-02 0:13 ` Linus Torvalds
2014-02-02 2:02 ` Al Viro
2014-02-02 19:21 ` Al Viro
2014-02-02 19:23 ` Al Viro
2014-02-03 14:41 ` Miklos Szeredi
2014-02-03 15:33 ` Al Viro
2014-02-02 23:16 ` Anton Altaparmakov
2014-02-03 15:12 ` Christoph Hellwig
2014-02-03 16:24 ` Al Viro
2014-02-03 16:50 ` Dave Kleikamp [this message]
2014-02-03 16:23 ` Dave Kleikamp
2014-02-04 12:44 ` Al Viro
2014-02-04 12:52 ` Kent Overstreet
2014-02-04 15:17 ` Al Viro
2014-02-04 17:27 ` Zach Brown
2014-02-04 17:35 ` Kent Overstreet
2014-02-04 18:08 ` Al Viro
2014-02-04 18:00 ` Al Viro
2014-02-04 18:33 ` Zach Brown
2014-02-04 18:36 ` Al Viro
2014-02-05 19:58 ` Al Viro
2014-02-05 20:42 ` Zach Brown
2014-02-06 9:08 ` Kent Overstreet
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