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From: Jan Kara <jack@suse.cz>
To: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Cc: tytso@mit.edu, jack@suse.cz, 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 v4 5/8] ext4: move inode extension/truncate code out from ->iomap_end() callback
Date: Tue, 8 Oct 2019 13:25:12 +0200
Message-ID: <20191008112512.GH5078@quack2.suse.cz> (raw)
In-Reply-To: <da556191f9dba2b477cce57665ded57bfd396463.1570100361.git.mbobrowski@mbobrowski.org>

On Thu 03-10-19 21:34:18, Matthew Bobrowski wrote:
> In preparation for implementing the iomap direct I/O write path
> modifications, the inode extension/truncate code needs to be moved out
> from ext4_iomap_end(). For direct I/O, if the current code remained
> within ext4_iomap_end() it would behave incorrectly. Updating the
> inode size prior to converting unwritten extents to written extents
> will potentially allow a racing direct I/O read operation to find
> unwritten extents before they've been correctly converted.
> 
> The inode extension/truncate code has been moved out into a new helper
> ext4_handle_inode_extension(). This function has been designed so that
> it can be used by both DAX and direct I/O paths.
> 
> Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>

Looks good to me. Fell free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

Just small nits below:

> +static int ext4_handle_inode_extension(struct inode *inode, loff_t offset,
> +				       ssize_t written, size_t count)
> +{
> +	int ret = 0;

I think both the function and callsites may be slightly simpler if you let
the function return 'written' or error (not 0 or error). But I'll leave
that decision upto you.

> +	handle_t *handle;
> +	bool truncate = false;
> +	u8 blkbits = inode->i_blkbits;
> +	ext4_lblk_t written_blk, end_blk;
> +
> +	/*
> +         * Note that EXT4_I(inode)->i_disksize can get extended up to
> +         * inode->i_size while the IO was running due to writeback of
> +         * delalloc blocks. But the code in ext4_iomap_alloc() is careful
> +         * to use zeroed / unwritten extents if this is possible and thus
> +         * we won't leave uninitialized blocks in a file even if we didn't
> +         * succeed in writing as much as we planned.
> +         */

Whitespace damaged here...

								Honza

-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

  reply index

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-03 11:32 [PATCH v4 0/8] ext4: port direct I/O to iomap infrastructure Matthew Bobrowski
2019-10-03 11:33 ` [PATCH v4 1/8] ext4: move out iomap field population into separate helper Matthew Bobrowski
2019-10-08 10:27   ` Jan Kara
2019-10-09  8:57     ` Matthew Bobrowski
2019-10-09 13:06       ` Jan Kara
2019-10-10  5:39         ` Matthew Bobrowski
2019-10-09  6:02   ` Ritesh Harjani
2019-10-09  7:07     ` Christoph Hellwig
2019-10-09  7:50       ` Ritesh Harjani
2019-10-09  9:09         ` Matthew Bobrowski
2019-10-03 11:33 ` [PATCH v4 2/8] ext4: move out IOMAP_WRITE path " Matthew Bobrowski
2019-10-08 10:31   ` Jan Kara
2019-10-09  9:18     ` Matthew Bobrowski
2019-10-09  6:22   ` Ritesh Harjani
2019-10-09  9:31     ` Matthew Bobrowski
2019-10-03 11:33 ` [PATCH v4 3/8] ext4: introduce new callback for IOMAP_REPORT operations Matthew Bobrowski
2019-10-08 10:42   ` Jan Kara
2019-10-09  9:41     ` Matthew Bobrowski
2019-10-09  6:00   ` Ritesh Harjani
2019-10-09 12:08     ` Matthew Bobrowski
2019-10-09 13:14       ` Ritesh Harjani
2019-10-03 11:34 ` [PATCH v4 4/8] ext4: introduce direct I/O read path using iomap infrastructure Matthew Bobrowski
2019-10-08 10:52   ` Jan Kara
2019-10-09 10:55     ` Matthew Bobrowski
2019-10-09  6:39   ` Ritesh Harjani
2019-10-03 11:34 ` [PATCH v4 5/8] ext4: move inode extension/truncate code out from ->iomap_end() callback Matthew Bobrowski
2019-10-08 11:25   ` Jan Kara [this message]
2019-10-09 10:18     ` Matthew Bobrowski
2019-10-09 12:51       ` Jan Kara
2019-10-10  5:44         ` Matthew Bobrowski
2019-10-09  6:27   ` Ritesh Harjani
2019-10-09 10:20     ` Matthew Bobrowski
2019-10-03 11:34 ` [PATCH v4 6/8] ext4: move inode extension checks out from ext4_iomap_alloc() Matthew Bobrowski
2019-10-08 11:27   ` Jan Kara
2019-10-09 10:21     ` Matthew Bobrowski
2019-10-09  6:30   ` Ritesh Harjani
2019-10-09 10:39     ` Matthew Bobrowski
2019-10-03 11:34 ` [PATCH v4 7/8] ext4: reorder map.m_flags checks in ext4_set_iomap() Matthew Bobrowski
2019-10-08 11:30   ` Jan Kara
2019-10-09 10:42     ` Matthew Bobrowski
2019-10-09  6:35   ` Ritesh Harjani
2019-10-09 10:43     ` Matthew Bobrowski
2019-10-03 11:35 ` [PATCH v4 8/8] ext4: introduce direct I/O write path using iomap infrastructure Matthew Bobrowski
2019-10-08 15:12   ` Jan Kara
2019-10-09  7:11     ` Christoph Hellwig
2019-10-09 13:41       ` Jan Kara
2019-10-09 11:53     ` Matthew Bobrowski

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