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From: Matthew Bobrowski <mbobrowski@mbobrowski.org>
To: Jan Kara <jack@suse.cz>
Cc: tytso@mit.edu, adilger.kernel@dilger.ca,
	linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	hch@infradead.org, david@fromorbit.com, darrick.wong@oracle.com
Subject: Re: [PATCH v5 02/12] ext4: iomap that extends beyond EOF should be marked dirty
Date: Tue, 22 Oct 2019 12:49:17 +1100	[thread overview]
Message-ID: <20191022014917.GB5092@athena.bobrowski.net> (raw)
In-Reply-To: <20191021132818.GB25184@quack2.suse.cz>

On Mon, Oct 21, 2019 at 03:28:18PM +0200, Jan Kara wrote:
> On Mon 21-10-19 20:17:46, Matthew Bobrowski wrote:
> > This patch is effectively addressed what Dave Chinner had found and
> > fixed within this commit: 8a23414ee345. Justification for needing this
> > modification has been provided below:
> > 
> > When doing a direct IO that spans the current EOF, and there are
> > written blocks beyond EOF that extend beyond the current write, the
> > only metadata update that needs to be done is a file size extension.
> > 
> > However, we don't mark such iomaps as IOMAP_F_DIRTY to indicate that
> > there is IO completion metadata updates required, and hence we may
> > fail to correctly sync file size extensions made in IO completion when
> > O_DSYNC writes are being used and the hardware supports FUA.
> > 
> > Hence when setting IOMAP_F_DIRTY, we need to also take into account
> > whether the iomap spans the current EOF. If it does, then we need to
> > mark it dirty so that IO completion will call generic_write_sync() to
> > flush the inode size update to stable storage correctly.
> > 
> > Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
> 
> Looks good to me. You could possibly also comment in the changelog that
> currently, this change doesn't have user visible impact for ext4 as none of
> current users of ext4_iomap_begin() that extend files depend of
> IOMAP_F_DIRTY.

Sure, I will add this.

> Also this patch would make slightly more sense to be before 1/12 so that
> you don't have there those two strange unused arguments. But these are just
> small nits.

You're right. I will rearrange it in v6 so that this patch comes
first.

> Feel free to add:
> 
> Reviewed-by: Jan Kara <jack@suse.cz>

Thanks Jan!

--<M>--

  reply	other threads:[~2019-10-22  1:49 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-21  9:17 [PATCH v5 00/12] ext4: port direct I/O to iomap infrastructure Matthew Bobrowski
2019-10-21  9:17 ` [PATCH v5 01/12] ext4: move set iomap routines into separate helper ext4_set_iomap() Matthew Bobrowski
2019-10-21 13:23   ` Jan Kara
2019-10-23  6:31   ` Ritesh Harjani
2019-10-23 10:14     ` Matthew Bobrowski
2019-10-21  9:17 ` [PATCH v5 02/12] ext4: iomap that extends beyond EOF should be marked dirty Matthew Bobrowski
2019-10-21 13:28   ` Jan Kara
2019-10-22  1:49     ` Matthew Bobrowski [this message]
2019-10-23  6:35   ` Ritesh Harjani
2019-10-23 10:20     ` Matthew Bobrowski
2019-10-21  9:18 ` [PATCH v5 03/12] ext4: split IOMAP_WRITE branch in ext4_iomap_begin() into helper Matthew Bobrowski
2019-10-21 13:31   ` Jan Kara
2019-10-23  6:37   ` Ritesh Harjani
2019-10-21  9:18 ` [PATCH v5 04/12] ext4: introduce new callback for IOMAP_REPORT Matthew Bobrowski
2019-10-21 13:37   ` Jan Kara
2019-10-22  1:55     ` Matthew Bobrowski
2019-10-23  6:39       ` Ritesh Harjani
2019-10-23 10:35         ` Matthew Bobrowski
2019-10-21  9:18 ` [PATCH v5 05/12] iomap: Allow forcing of waiting for running DIO in iomap_dio_rw() mbobrowski
2019-10-24  1:41   ` Christoph Hellwig
2019-10-24 11:17     ` Matthew Bobrowski
2019-10-21  9:18 ` [PATCH v5 06/12] xfs: Use iomap_dio_rw_wait() mbobrowski
2019-10-21 13:38   ` Jan Kara
2019-10-21  9:18 ` [PATCH v5 07/12] ext4: introduce direct I/O read using iomap infrastructure Matthew Bobrowski
2019-10-21 13:41   ` Jan Kara
2019-10-22  1:58     ` Matthew Bobrowski
2019-10-23  6:40   ` Ritesh Harjani
2019-10-21  9:18 ` [PATCH v5 08/12] ext4: update direct I/O read to do trylock in IOCB_NOWAIT cases Matthew Bobrowski
2019-10-21 13:48   ` Jan Kara
2019-10-22  2:04     ` Matthew Bobrowski
2019-10-22  7:50       ` Jan Kara
2019-10-23  6:51   ` Ritesh Harjani
2019-10-21  9:18 ` [PATCH v5 09/12] ext4: move inode extension/truncate code out from ->iomap_end() callback Matthew Bobrowski
2019-10-21 13:53   ` Jan Kara
2019-10-22  2:07     ` Matthew Bobrowski
2019-10-21  9:20 ` [PATCH v5 12/12] ext4: introduce direct I/O write using iomap infrastructure Matthew Bobrowski
2019-10-21 16:18   ` Jan Kara
2019-10-22  3:02     ` Matthew Bobrowski
2019-10-22  7:55       ` Jan Kara
2019-10-21  9:20 ` [PATCH v5 11/12] ext4: reorder map->m_flags checks in ext4_set_iomap() Matthew Bobrowski
2019-10-21  9:20 ` [PATCH v5 10/12] ext4: move inode extension check out from ext4_iomap_alloc() Matthew Bobrowski
2019-10-21 13:31 ` [PATCH v5 00/12] ext4: port direct I/O to iomap infrastructure Theodore Y. Ts'o
2019-10-21 19:43   ` Jan Kara
2019-10-21 22:38     ` Dave Chinner
2019-10-22  8:01       ` Jan Kara
2019-10-23  2:35     ` Matthew Bobrowski
2019-10-23 10:01       ` Jan Kara
2019-10-23 10:11         ` Matthew Bobrowski
2019-10-24  1:58           ` Christoph Hellwig
2019-10-24 11:09             ` Matthew Bobrowski

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