linux-ext4 - Re: [PATCH v3 4/6] ext4: reorder map.m_flags checks in ext4_iomap

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Date:   Tue, 24 Sep 2019 19:35:18 +1000
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,
        david@...morbit.com, hch@...radead.org, darrick.wong@...cle.com
Subject: Re: [PATCH v3 4/6] ext4: reorder map.m_flags checks in
 ext4_iomap_begin()

On Mon, Sep 23, 2019 at 05:08:56PM +0200, Jan Kara wrote:
> On Thu 12-09-19 21:04:30, Matthew Bobrowski wrote:
> > For iomap direct IO write code path changes, we need to accommodate
> > for the case where the block mapping flags passed to ext4_map_blocks()
> > will result in m_flags having both EXT4_MAP_MAPPED and
> > EXT4_MAP_UNWRITTEN bits set. In order for the allocated unwritten
> > extents to be converted properly in the end_io handler, iomap->type
> > must be set to IOMAP_UNWRITTEN, so we need to reshuffle the
> > conditional statement in order to achieve this.
> > 
> > This change is a no-op for DAX code path as the block mapping flag
> > passed to ext4_map_blocks() when IS_DAX(inode) never results in
> > EXT4_MAP_MAPPED and EXT4_MAP_UNWRITTEN being set at once.
> > 
> > Signed-off-by: Matthew Bobrowski <mbobrowski@...browski.org>
> > Reviewed-by: Ritesh Harjani <riteshh@...ux.ibm.com>
> 
> The patch looks good to me. You can add:
> 
> Reviewed-by: Jan Kara <jack@...e.cz>

Thank you Jan!

Note that the updated patch series that I'll send through shortly has slightly
changed in the sense that I've split up a whole bunch of the iomap code. The
idea behind this was to reduce the overall clutter that exists within the
->iomap_begin() callback. This was recommended by Christoph, and I really like
the idea because moving forward it makes complete sense to do so. This
specific patch will remain as is though.

--<M>--