From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@lst.de>
Date: Wed, 30 May 2018 11:57:36 +0200
Subject: [Cluster-devel] [PATCH v5 14/14] gfs2: Handle stuffed files
	in	iomap_{begin, end}
In-Reply-To: <20180530094842.13559-15-agruenba@redhat.com>
References: <20180530094842.13559-1-agruenba@redhat.com>
	<20180530094842.13559-15-agruenba@redhat.com>
Message-ID: <20180530095736.GA31068@lst.de>
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> +	if (gfs2_is_stuffed(ip)) {
> +		unstuff = pos + length > gfs2_max_stuffed_size(ip);
> +
> +		if (!unstuff) {
> +			iomap->page = grab_cache_page_write_begin(
> +					inode->i_mapping, 0, flags);
> +			ret = -ENOMEM;
> +			if (!iomap->page)
> +				goto out;
> +
> +			if (!PageUptodate(iomap->page)) {
> +				ret = stuffed_readpage(ip, iomap->page);
> +				if (ret)
> +					goto out;
> +			}
> +		}
> +	}

grab_cache_page_write_begin needs to remain in iomap.  Please just
set up a pointer for later copying here.

This will be important to support e.g. iomap_readpage(s) and to easily
support direct I/O from inline data (just copy to/from the stuffed
data pointer in iomap).