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From: Matthew Bobrowski <mbobrowski@mbobrowski.org>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: RITESH HARJANI <riteshh@linux.ibm.com>,
	linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	jack@suse.cz, tytso@mit.edu
Subject: Re: [PATCH 4/5] ext4: introduce direct IO write code path using iomap infrastructure
Date: Wed, 14 Aug 2019 19:51:37 +1000
Message-ID: <20190814095135.GB23465@poseidon.bobrowski.net> (raw)
In-Reply-To: <20190813143540.GA7126@magnolia>

On Tue, Aug 13, 2019 at 07:35:40AM -0700, Darrick J. Wong wrote:
> On Tue, Aug 13, 2019 at 10:58:42PM +1000, Matthew Bobrowski wrote:
> > On Mon, Aug 12, 2019 at 10:34:29PM +0530, RITESH HARJANI wrote:
> > > > +
> > > > +	if (ret >= 0 && iov_iter_count(from)) {
> > > > +		overwrite ? inode_unlock_shared(inode) : inode_unlock(inode);
> > > > +		return ext4_buffered_write_iter(iocb, from);
> > > > +	}
> > > should not we copy code from "__generic_file_write_iter" which does below?
> > > 
> > > 3436                 /*
> > > 3437                  * We need to ensure that the page cache pages are
> > > written to
> > > 3438                  * disk and invalidated to preserve the expected
> > > O_DIRECT
> > > 3439                  * semantics.
> > > 3440                  */
> > 
> > Hm, I don't see why this would be required seeing as though the page cache
> > invalidation semantics pre and post write are handled by iomap_dio_rw() and
> > iomap_dio_complete(). But, I could be completely wrong here, so we may need to
> > wait for some others to provide comments on this.
> 
> iomap_dio_rw is supposed to zap the page cache before the write and
> again afterwards (and whine if someone is racing buffered and direct
> writes to the same file location), so ext4 shouldn't need to do that
> itself.

Thanks for confirming Darrick! I thought that was the case.

--M

  reply index

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-12 12:52 [PATCH 0/5] ext4: direct IO via " Matthew Bobrowski
2019-08-12 12:52 ` [PATCH 1/5] ext4: introduce direct IO read code path using " Matthew Bobrowski
2019-08-12 17:18   ` Christoph Hellwig
2019-08-12 20:17     ` Matthew Wilcox
2019-08-13 10:45       ` Matthew Bobrowski
2019-08-12 12:52 ` [PATCH 2/5] ext4: move inode extension/truncate code out from ext4_iomap_end() Matthew Bobrowski
2019-08-12 17:18   ` Christoph Hellwig
2019-08-13 10:46     ` Matthew Bobrowski
2019-08-28 19:59   ` Jan Kara
2019-08-28 21:54     ` Matthew Bobrowski
2019-08-29  8:18       ` Jan Kara
2019-08-12 12:53 ` [PATCH 3/5] iomap: modify ->end_io() calling convention Matthew Bobrowski
2019-08-12 17:18   ` Christoph Hellwig
2019-08-13 10:43     ` Matthew Bobrowski
2019-08-12 12:53 ` [PATCH 4/5] ext4: introduce direct IO write code path using iomap infrastructure Matthew Bobrowski
2019-08-12 17:04   ` RITESH HARJANI
2019-08-13 12:58     ` Matthew Bobrowski
2019-08-13 14:35       ` Darrick J. Wong
2019-08-14  9:51         ` Matthew Bobrowski [this message]
2019-08-12 17:34   ` Christoph Hellwig
2019-08-13 10:45     ` Matthew Bobrowski
2019-08-28 20:26   ` Jan Kara
2019-08-28 22:32     ` Dave Chinner
2019-08-29  8:03       ` Jan Kara
2019-08-29 11:47       ` Matthew Bobrowski
2019-08-29 11:45     ` Matthew Bobrowski
2019-08-29 12:38       ` Jan Kara
2019-08-12 12:53 ` [PATCH 5/5] ext4: clean up redundant buffer_head direct IO code Matthew Bobrowski
2019-08-12 17:31 ` [PATCH 0/5] ext4: direct IO via iomap infrastructure RITESH HARJANI
2019-08-13 11:10   ` Matthew Bobrowski
2019-08-13 12:27     ` RITESH HARJANI
2019-08-14  9:48       ` Matthew Bobrowski
2019-08-14 11:58         ` RITESH HARJANI
2019-08-21 13:14       ` Matthew Bobrowski
2019-08-22 12:00         ` Matthew Bobrowski
2019-08-22 14:11           ` Ritesh Harjani
2019-08-24  3:18             ` Matthew Bobrowski
2019-08-24  3:55               ` Darrick J. Wong
2019-08-24 23:04                 ` Christoph Hellwig
2019-08-27  9:52                   ` Matthew Bobrowski
2019-08-28 12:05                     ` Matthew Bobrowski
2019-08-28 14:27                       ` Theodore Y. Ts'o
2019-08-28 18:02                         ` Jan Kara
2019-08-29  6:36                           ` Christoph Hellwig
2019-08-29 11:20                             ` Matthew Bobrowski
2019-08-29 14:41                               ` Christoph Hellwig
2019-08-23 13:43           ` [RFC 1/1] ext4: PoC implementation of option-1 Ritesh Harjani
2019-08-23 13:49             ` Ritesh Harjani

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