linux-kernel - Re: [PATCH v3] ocfs2: Let ocfs2_setattr use new truncate sequence.

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Message-ID: <20100610055857.GB30672@mail.oracle.com>
Date:	Wed, 9 Jun 2010 22:58:57 -0700
From:	Joel Becker <Joel.Becker@...cle.com>
To:	Tao Ma <tao.ma@...cle.com>, Al Viro <viro@....linux.org.uk>
Cc:	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	Christoph Hellwig <hch@....de>, Nick Piggin <npiggin@...e.de>
Subject: Re: [PATCH v3] ocfs2: Let ocfs2_setattr use new truncate sequence.

Acked-by: Joel Becker <joel.becker@...cle.com>

Al, can you carry this atop the truncate sequence code?

Joel

On Thu, Jun 10, 2010 at 01:08:05PM +0800, Tao Ma wrote:
> Let ocfs2 use the new truncate sequence. The changes include:
> 1. Use truncate_setsize directly since we don't implement our
>    own ->truncate and what we need is "update i_size and
>    truncate_pagecache" which truncate_setsize now does.
> 2. For direct write, ocfs2 actually don't allow write to pass
>    i_size(see ocfs2_prepare_inode_for_write), so we don't have
>    a chance to increase i_size. So remove the bogus check.
> 
> Cc: Joel Becker <joel.becker@...cle.com>
> Cc: Christoph Hellwig <hch@....de>
> Cc: Nick Piggin <npiggin@...e.de>
> Signed-off-by: Tao Ma <tao.ma@...cle.com>
> ---
>  fs/ocfs2/file.c |   32 ++++++--------------------------
>  1 files changed, 6 insertions(+), 26 deletions(-)
> 
> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
> index 1fb0985..8b5447e 100644
> --- a/fs/ocfs2/file.c
> +++ b/fs/ocfs2/file.c
> @@ -987,7 +987,7 @@ int ocfs2_setattr(struct dentry *dentry, struct iattr *attr)
>  		if (status)
>  			goto bail_unlock;
>  
> -		if (i_size_read(inode) > attr->ia_size) {
> +		if (inode->i_size > attr->ia_size) {
>  			if (ocfs2_should_order_data(inode)) {
>  				status = ocfs2_begin_ordered_truncate(inode,
>  								      attr->ia_size);
> @@ -1052,22 +1052,13 @@ int ocfs2_setattr(struct dentry *dentry, struct iattr *attr)
>  	}
>  
>  	/*
> -	 * This will intentionally not wind up calling truncate_setsize(),
> -	 * since all the work for a size change has been done above.
> -	 * Otherwise, we could get into problems with truncate as
> -	 * ip_alloc_sem is used there to protect against i_size
> -	 * changes.
> -	 *
> -	 * XXX: this means the conditional below can probably be removed.
> +	 * Since all the work for a size change has been done above.
> +	 * Call truncate_setsize directly to change size and truncate
> +	 * pagecache.
>  	 */
>  	if ((attr->ia_valid & ATTR_SIZE) &&
> -	    attr->ia_size != i_size_read(inode)) {
> -		status = vmtruncate(inode, attr->ia_size);
> -		if (status) {
> -			mlog_errno(status);
> -			goto bail_commit;
> -		}
> -	}
> +	    attr->ia_size != inode->i_size)
> +		truncate_setsize(inode, attr->ia_size);
>  
>  	setattr_copy(inode, attr);
>  	mark_inode_dirty(inode);
> @@ -2122,17 +2113,6 @@ relock:
>  		written = generic_file_direct_write(iocb, iov, &nr_segs, *ppos,
>  						    ppos, count, ocount);
>  		if (written < 0) {
> -			/*
> -			 * direct write may have instantiated a few
> -			 * blocks outside i_size. Trim these off again.
> -			 * Don't need i_size_read because we hold i_mutex.
> -			 *
> -			 * XXX(truncate): this looks buggy because ocfs2 did not
> -			 * actually implement ->truncate.  Take a look at
> -			 * the new truncate sequence and update this accordingly
> -			 */
> -			if (*ppos + count > inode->i_size)
> -				truncate_setsize(inode, inode->i_size);
>  			ret = written;
>  			goto out_dio;
>  		}
> -- 
> 1.5.5
> 

-- 

"If you took all of the grains of sand in the world, and lined
 them up end to end in a row, you'd be working for the government!"
	- Mr. Interesting

Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker@...cle.com
Phone: (650) 506-8127
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