From: Li Dongyang <lidongyang@novell.com>
Date: Mon, 26 Apr 2010 17:56:38 +0800
Subject: [Ocfs2-devel] [PATCH] ocfs2: avoid direct write if we fall back
	to buffered v3
In-Reply-To: <201004171749.10674.lidongyang@novell.com>
References: <201004171749.10674.lidongyang@novell.com>
Message-ID: <201004261756.38559.lidongyang@novell.com>
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To: ocfs2-devel@oss.oracle.com

On Saturday 17 April 2010 17:49:10 Li Dongyang wrote:
> when we fall back to buffered write from direct write, we call
> __generic_file_aio_write but that will end up doing direct write
> even we are only prepared to do buffered write because the file
> has O_DIRECT flag set. This is a fix for
> https://bugzilla.novell.com/show_bug.cgi?id=591039
> revised with Joel's comments.
> 
> Signed-off-by: Li Dongyang <lidongyang@novell.com>
> ---
>  fs/ocfs2/file.c |   25 ++++++++++++++-----------
>  1 files changed, 14 insertions(+), 11 deletions(-)
> 
> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
> index de059f4..0c15be9 100644
> --- a/fs/ocfs2/file.c
> +++ b/fs/ocfs2/file.c
> @@ -1973,18 +1973,18 @@ relock:
>  	/* communicate with ocfs2_dio_end_io */
>  	ocfs2_iocb_set_rw_locked(iocb, rw_level);
> 
> -	if (direct_io) {
> -		ret = generic_segment_checks(iov, &nr_segs, &ocount,
> -					     VERIFY_READ);
> -		if (ret)
> -			goto out_dio;
> +	ret = generic_segment_checks(iov, &nr_segs, &ocount,
> +				     VERIFY_READ);
> +	if (ret)
> +		goto out_dio;
> 
> -		count = ocount;
> -		ret = generic_write_checks(file, ppos, &count,
> -					   S_ISBLK(inode->i_mode));
> -		if (ret)
> -			goto out_dio;
> +	count = ocount;
> +	ret = generic_write_checks(file, ppos, &count,
> +				   S_ISBLK(inode->i_mode));
> +	if (ret)
> +		goto out_dio;
> 
> +	if (direct_io) {
>  		written = generic_file_direct_write(iocb, iov, &nr_segs, *ppos,
>  						    ppos, count, ocount);
>  		if (written < 0) {
> @@ -1999,7 +1999,10 @@ relock:
>  			goto out_dio;
>  		}
>  	} else {
> -		written = __generic_file_aio_write(iocb, iov, nr_segs, ppos);
> +		current->backing_dev_info = file->f_mapping->backing_dev_info;
> +		written = generic_file_buffered_write(iocb, iov, nr_segs, *ppos
> +						      ppos, count, 0);
> +		current->backing_dev_info = NULL;
>  	}
> 
>  out_dio:
> 
Joel, any comments on this update?
Br,
Li Dongyang