linux-ext4 - Re: [PATCH v4 3/8] ext4: introduce new callback for IOMAP

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Message-ID: <20191009094128.GF2125@poseidon.bobrowski.net>
Date:   Wed, 9 Oct 2019 20:41:29 +1100
From:   Matthew Bobrowski <mbobrowski@...browski.org>
To:     Jan Kara <jack@...e.cz>
Cc:     tytso@....edu, adilger.kernel@...ger.ca,
        linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        hch@...radead.org, david@...morbit.com, darrick.wong@...cle.com
Subject: Re: [PATCH v4 3/8] ext4: introduce new callback for IOMAP_REPORT
 operations

On Tue, Oct 08, 2019 at 12:42:09PM +0200, Jan Kara wrote:
> On Thu 03-10-19 21:33:45, Matthew Bobrowski wrote:
> The patch looks good to me. You can add:
> 
> Reviewed-by: Jan Kara <jack@...e.cz>

Thanks Jan! :)

> It would just need small adjustments if you change patch 1 as I suggested:

I will await what you say in response to what my thoughts were aronud
ext4_set_iomap() before doing any updates here.

> > +static u16 ext4_iomap_check_delalloc(struct inode *inode,
> > +				     struct ext4_map_blocks *map)
> > +{
> > +	struct extent_status es;
> > +	ext4_lblk_t end = map->m_lblk + map->m_len - 1;
> > +
> > +	ext4_es_find_extent_range(inode, &ext4_es_is_delayed, map->m_lblk,
> > +				  end, &es);
> > +
> > +	/* Entire range is a hole */
> > +	if (!es.es_len || es.es_lblk > end)
> > +		return IOMAP_HOLE;
> > +	if (es.es_lblk <= map->m_lblk) {
> > +		ext4_lblk_t offset = 0;
> > +
> > +		if (es.es_lblk < map->m_lblk)
> > +			offset = map->m_lblk - es.es_lblk;
> > +		map->m_lblk = es.es_lblk + offset;
> > +		map->m_len = es.es_len - offset;
> > +		return IOMAP_DELALLOC;
> > +	}
> > +
> > +	/* Range starts with a hole */
> > +	map->m_len = es.es_lblk - map->m_lblk;
> > +	return IOMAP_HOLE;
> > +}
> 
> This function would then be IMO better off to directly update 'iomap' as
> needed after ext4_set_iomap() sets hole there.

As mentioned in 1/8, it would be nice to leave all iomap setting up to
ext4_set_iomap(), but if we're strongly against passing 'type', then
I'm happy to change it and update this to pass an 'iomap'.

--<M>--