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Date:   Fri, 23 Jul 2021 23:23:38 +0800
From:   Gao Xiang <hsiangkao@linux.alibaba.com>
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Christoph Hellwig <hch@lst.de>, linux-erofs@lists.ozlabs.org,
        linux-fsdevel@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        "Darrick J . Wong" <djwong@kernel.org>,
        Andreas Gruenbacher <andreas.gruenbacher@gmail.com>
Subject: Re: [PATCH v6] iomap: support tail packing inline read
Message-ID: <YPre+j906ywgRHEZ@B-P7TQMD6M-0146.local>
Mail-Followup-To: Matthew Wilcox <willy@infradead.org>,
        Christoph Hellwig <hch@lst.de>, linux-erofs@lists.ozlabs.org,
        linux-fsdevel@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        "Darrick J . Wong" <djwong@kernel.org>,
        Andreas Gruenbacher <andreas.gruenbacher@gmail.com>
References: <20210722031729.51628-1-hsiangkao@linux.alibaba.com>
 <20210722053947.GA28594@lst.de>
 <YPrauRjG7+vCw7f9@casper.infradead.org>
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Hi Matthew,

On Fri, Jul 23, 2021 at 04:05:29PM +0100, Matthew Wilcox wrote:
> On Thu, Jul 22, 2021 at 07:39:47AM +0200, Christoph Hellwig wrote:
> > @@ -675,7 +676,7 @@ static size_t iomap_write_end_inline(struct inode *inode, struct page *page,
> >  
> >  	flush_dcache_page(page);
> >  	addr = kmap_atomic(page);
> > -	memcpy(iomap->inline_data + pos, addr + pos, copied);
> > +	memcpy(iomap_inline_buf(iomap, pos), addr + pos, copied);
> 
> This is wrong; pos can be > PAGE_SIZE, so this needs to be
> addr + offset_in_page(pos).

Yeah, thanks for pointing out. It seems so, since EROFS cannot test
such write path, previously it was disabled explicitly. I could
update it in the next version as above.

Thanks,
Gao Xiang