From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: [patch] fs: remove prepare_write/commit_write
Date: Wed, 24 Sep 2008 19:48:19 -0400
Message-ID: <20080924234819.GA16344@infradead.org>
References: <20080924234116.GC30307@wotan.suse.de>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: Badari Pulavarty <pbadari@us.ibm.com>,
	linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org
To: Nick Piggin <npiggin@suse.de>
Return-path: <linux-fsdevel-owner@vger.kernel.org>
Received: from bombadil.infradead.org ([18.85.46.34]:34706 "EHLO
	bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1752215AbYIXXsZ (ORCPT
	<rfc822;linux-fsdevel@vger.kernel.org>);
	Wed, 24 Sep 2008 19:48:25 -0400
Content-Disposition: inline
In-Reply-To: <20080924234116.GC30307@wotan.suse.de>
Sender: linux-fsdevel-owner@vger.kernel.org
List-ID: <linux-fsdevel.vger.kernel.org>

On Thu, Sep 25, 2008 at 01:41:16AM +0200, Nick Piggin wrote:
> --- linux-2.6.orig/mm/filemap.c
> +++ linux-2.6/mm/filemap.c
> @@ -2016,48 +2016,8 @@ int pagecache_write_begin(struct file *f
>  {
>  	const struct address_space_operations *aops = mapping->a_ops;
>  
> +	return aops->write_begin(file, mapping, pos, len, flags,
>  							pagep, fsdata);
>  }
>  EXPORT_SYMBOL(pagecache_write_begin);

Please kill pagecache_write_begin/pagecache_write_end, too.

>  static ssize_t generic_perform_write(struct file *file,
>  				struct iov_iter *i, loff_t pos)
>  {
> @@ -2481,10 +2253,7 @@ generic_file_buffered_write(struct kiocb
>  	struct iov_iter i;
>  
>  	iov_iter_init(&i, iov, nr_segs, count, written);
> -	if (a_ops->write_begin)
> -		status = generic_perform_write(file, &i, pos);
> -	else
> -		status = generic_perform_write_2copy(file, &i, pos);
> +	status = generic_perform_write(file, &i, pos);
>  
>  	if (likely(status >= 0)) {
>  		written += status;

Can we merge generic_perform_write back into
generic_file_buffered_write?  generic_file_buffered_write is left as a
rather useless wrapper after this.

> -	->prepare_write(), ->commit_write(), ->sync_page() and ->readpage()
> +	->write_begin(), ->write_end(), ->sync_page() and ->readpage()
>  may be called from the request handler (/dev/loop).

This comment can go away, all file I/O done by the loop device now is
from a kthread.