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From: Matthew Bobrowski <mbobrowski@mbobrowski.org>
To: Ritesh Harjani <riteshh@linux.ibm.com>
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 2/8] ext4: move out IOMAP_WRITE path into separate helper
Date: Wed, 9 Oct 2019 20:31:46 +1100
Message-ID: <20191009093144.GD2125@poseidon.bobrowski.net> (raw)
In-Reply-To: <20191009062242.87D244204B@d06av24.portsmouth.uk.ibm.com>

On Wed, Oct 09, 2019 at 11:52:41AM +0530, Ritesh Harjani wrote:
> On 10/3/19 5:03 PM, Matthew Bobrowski wrote:
> Minor comment, but otherwise.
> Patch looks good to me. You may add:
> 
> Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>

*nod* - Thank you!

> >   static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> >   			    unsigned flags, struct iomap *iomap)
> >   {
> > @@ -3500,62 +3556,16 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> >   			}
> >   		}
> >   	} else if (flags & IOMAP_WRITE) {
> > -		int dio_credits;
> > -		handle_t *handle;
> > -		int retries = 0;
> > -
> > -		/* Trim mapping request to maximum we can map at once for DIO */
> > -		if (map.m_len > DIO_MAX_BLOCKS)
> > -			map.m_len = DIO_MAX_BLOCKS;
> > -		dio_credits = ext4_chunk_trans_blocks(inode, map.m_len);
> > -retry:
> > -		/*
> > -		 * Either we allocate blocks and then we don't get unwritten
> > -		 * extent so we have reserved enough credits, or the blocks
> > -		 * are already allocated and unwritten and in that case
> > -		 * extent conversion fits in the credits as well.
> > -		 */
> > -		handle = ext4_journal_start(inode, EXT4_HT_MAP_BLOCKS,
> > -					    dio_credits);
> > -		if (IS_ERR(handle))
> > -			return PTR_ERR(handle);
> > -
> > -		ret = ext4_map_blocks(handle, inode, &map,
> > -				      EXT4_GET_BLOCKS_CREATE_ZERO);
> > -		if (ret < 0) {
> > -			ext4_journal_stop(handle);
> > -			if (ret == -ENOSPC &&
> > -			    ext4_should_retry_alloc(inode->i_sb, &retries))
> > -				goto retry;
> > -			return ret;
> > -		}
> > -
> > -		/*
> > -		 * If we added blocks beyond i_size, we need to make sure they
> > -		 * will get truncated if we crash before updating i_size in
> > -		 * ext4_iomap_end(). For faults we don't need to do that (and
> > -		 * even cannot because for orphan list operations inode_lock is
> > -		 * required) - if we happen to instantiate block beyond i_size,
> > -		 * it is because we race with truncate which has already added
> > -		 * the inode to the orphan list.
> > -		 */
> > -		if (!(flags & IOMAP_FAULT) && first_block + map.m_len >
> > -		    (i_size_read(inode) + (1 << blkbits) - 1) >> blkbits) {
> > -			int err;
> > -
> > -			err = ext4_orphan_add(handle, inode);
> > -			if (err < 0) {
> > -				ext4_journal_stop(handle);
> > -				return err;
> > -			}
> > -		}
> > -		ext4_journal_stop(handle);
> > +		ret = ext4_iomap_alloc(inode, flags, first_block, &map);
> 
> We don't need "first_block" argument here. Since
> map->m_lblk saves first_block directly above in the same function.

You're right. I will change that.

> No strong objection against ext4_iomap_alloc, but
> maybe ext4_iomap_map_write sounds better?
> Either way is fine though.

I like 'ext4_iomap_alloc', because it's performing allocation in
preparation for a write being performed on behalf of iomap. :)

--<M>--


  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 [this message]
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
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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