linux-ext4 - Re: [PATCH 5/8] xfs: Protect xfs_file_aio_write() & xfs_setattr_size() with sb_start_write

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Message-ID: <20120205231127.GH6922@dastard>
Date:	Mon, 6 Feb 2012 10:11:27 +1100
From:	Dave Chinner <david@...morbit.com>
To:	Eric Sandeen <sandeen@...deen.net>
Cc:	Jan Kara <jack@...e.cz>, Alex Elder <elder@...nel.org>,
	Surbhi Palande <csurbhi@...il.com>,
	Kamal Mostafa <kamal@...onical.com>,
	LKML <linux-kernel@...r.kernel.org>, xfs@....sgi.com,
	Christoph Hellwig <hch@...radead.org>, Ben Myers <bpm@....com>,
	Dave Chinner <dchinner@...hat.com>,
	linux-fsdevel@...r.kernel.org, linux-ext4@...r.kernel.org
Subject: Re: [PATCH 5/8] xfs: Protect xfs_file_aio_write() &
 xfs_setattr_size() with sb_start_write - sb_end_write

On Fri, Feb 03, 2012 at 10:30:05PM -0600, Eric Sandeen wrote:
> On 1/20/12 2:34 PM, Jan Kara wrote:
> > Replace racy xfs_wait_for_freeze() check in xfs_file_aio_write() with
> > a reliable sb_start_write() - sb_end_write() locking.
> 
> Here's what I'm running with now.  With this and my modified
> patch6, I can pass xfstests 068 on xfs.

Just a quick question this raises - is .splice_write() protected?

Cheers,

Dave.
> 
> -Eric
> 
> 
> 
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 7e5bc87..f1cacdc 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -874,11 +874,11 @@ xfs_file_aio_write(
>  	if (ocount == 0)
>  		return 0;
>  
> -	xfs_wait_for_freeze(ip->i_mount, SB_FREEZE_WRITE);
> -
>  	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
>  		return -EIO;
>  
> +	sb_start_write(inode->i_sb, SB_FREEZE_WRITE);
> +

This check really should go before the shutdown check - if the
filesystem shuts down while we are freezing or attempting to freeze,
we want to abort the write after we are woken....

Cheers,

Dave.
-- 
Dave Chinner
david@...morbit.com
--
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