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Date:   Mon, 26 Jul 2021 15:27:49 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Andreas =?iso-8859-1?Q?Gr=FCnbacher?= 
        <andreas.gruenbacher@gmail.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        Andreas Gruenbacher <agruenba@redhat.com>,
        Gao Xiang <hsiangkao@linux.alibaba.com>,
        "Darrick J . Wong" <djwong@kernel.org>,
        Matthew Wilcox <willy@infradead.org>,
        Huang Jianan <huangjianan@oppo.com>,
        linux-erofs@lists.ozlabs.org,
        Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v7] iomap: make inline data support more flexible
Message-ID: <20210726132749.GA6535@lst.de>
References: <CAHpGcMKZP8b3TbRv3D-pcrE_iDU5TKUFHst9emuQmRPntFSArA@mail.gmail.com> <CAHpGcMJBhWcwteLDSBU3hgwq1tk_+LqogM1ZM=Fv8U0VtY5hMg@mail.gmail.com> <20210723174131.180813-1-hsiangkao@linux.alibaba.com> <20210725221639.426565-1-agruenba@redhat.com> <YP4zUvnBCAb86Mny@B-P7TQMD6M-0146.local> <20210726110611.459173-1-agruenba@redhat.com> <20210726121702.GA528@lst.de> <CAHpGcMJhuSApy4eg9jKe2pYq4d7bY-Lg-Bmo9tOANghQ2Hxo-A@mail.gmail.com>
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On Mon, Jul 26, 2021 at 02:27:12PM +0200, Andreas Gr?nbacher wrote:
> > That is how can size be different from iomap->length?
> 
> Quoting from my previous reply,
> 
> "In the iomap_readpage case (iomap_begin with flags == 0),
> iomap->length will be the amount of data up to the end of the inode.
> In the iomap_file_buffered_write case (iomap_begin with flags ==
> IOMAP_WRITE), iomap->length will be the size of iomap->inline_data.
> (For extending writes, we need to write beyond the current end of
> inode.) So iomap->length isn't all that useful for
> iomap_read_inline_data."

I think we should fix that now that we have the srcmap concept.
That is or IOMAP_WRITE|IOMAP_ZERO return the inline map as the soure
map, and return the actual block map we plan to write into as the
main iomap.

> 
> > Shouldn't the offset_in_page also go into iomap_inline_data_size_valid,
> > which should probably be called iomap_inline_data_valid then?
> 
> Hmm, not sure what you mean: iomap_inline_data_size_valid does take
> offset_in_page(iomap->inline_data) into account.

Indeed, orry for the braino.

> I thought people were okay with 80 character long lines?

No.