linux-ext4 - Re: [PATCH v4 5/8] ext4: move inode extension/truncate code out from ->iomap

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Message-ID: <20191009101848.GG2125@poseidon.bobrowski.net>
Date:   Wed, 9 Oct 2019 21:18:50 +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 5/8] ext4: move inode extension/truncate code out from
 ->iomap_end() callback

On Tue, Oct 08, 2019 at 01:25:12PM +0200, Jan Kara wrote:
> On Thu 03-10-19 21:34:18, Matthew Bobrowski wrote:
> Looks good to me. Fell free to add:
> 
> Reviewed-by: Jan Kara <jack@...e.cz>

Thanks Jan!

> 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.

Hm, don't we actually need to return 0 for success cases so that
iomap_dio_complete() behaves correctly i.e. increments iocb->ki_pos,
etc?

> > +	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...

I'll fix this.

--<M>--