[PATCH 2/4] xfs: make sure xfs_sync_fsdata covers the log

[Alex Elder]

Christoph Hellwig wrote:
> From: Dave Chinner <david at fromorbit.com>
> 
> We want to always cover the log after writing out the superblock, and
> in case of a synchronous writeout make sure we actually wait for the
> log to be covered.  That way a filesystem that has been sync()ed can
> be considered clean by log recovery.
> 
> Signed-off-by: Dave Chinner <david at fromorbit.com>
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> Reviewed-by: Eric Sandeen <sandeen at sandeen.net>



Looks good.

Reviewed-by: Alex Elder <aelder at sgi.com>



> Index: linux-2.6/fs/xfs/linux-2.6/xfs_sync.c
> ===================================================================
> --- linux-2.6.orig/fs/xfs/linux-2.6/xfs_sync.c	2009-07-07 16:03:51.871239376 +0200
> +++ linux-2.6/fs/xfs/linux-2.6/xfs_sync.c	2009-07-07 18:24:48.722251281 +0200
> @@ -309,11 +309,15 @@ xfs_sync_attr(
>  STATIC int
>  xfs_commit_dummy_trans(
>  	struct xfs_mount	*mp,
> -	uint			log_flags)
> +	uint			flags)
>  {
>  	struct xfs_inode	*ip = mp->m_rootip;
>  	struct xfs_trans	*tp;
>  	int			error;
> +	int			log_flags = XFS_LOG_FORCE;
> +
> +	if (flags & SYNC_WAIT)
> +		log_flags |= XFS_LOG_SYNC;
> 
>  	/*
>  	 * Put a dummy transaction in the log to tell recovery
> @@ -331,13 +335,12 @@ xfs_commit_dummy_trans(
>  	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
>  	xfs_trans_ihold(tp, ip);
>  	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
> -	/* XXX(hch): ignoring the error here.. */
>  	error = xfs_trans_commit(tp, 0);
> -
>  	xfs_iunlock(ip, XFS_ILOCK_EXCL);
> 
> +	/* the log force ensures this transaction is pushed to disk */
>  	xfs_log_force(mp, 0, log_flags);
> -	return 0;
> +	return error;
>  }
> 
>  int
> @@ -377,6 +380,7 @@ xfs_sync_fsdata(
>  		 */
>  		if (XFS_BUF_ISPINNED(bp))
>  			xfs_log_force(mp, 0, XFS_LOG_FORCE);
> +		xfs_flush_buftarg(mp->m_ddev_targp, 1);
>  	}
> 
> 
> @@ -385,7 +389,10 @@ xfs_sync_fsdata(
>  	else
>  		XFS_BUF_ASYNC(bp);
> 
> -	return xfs_bwrite(mp, bp);
> +	error = xfs_bwrite(mp, bp);
> +	if (!error && xfs_log_need_covered(mp))
> +		error = xfs_commit_dummy_trans(mp, (flags & SYNC_WAIT));
> +	return error;
> 
>   out_brelse:
>  	xfs_buf_relse(bp);
> @@ -571,8 +578,6 @@ xfs_sync_worker(
>  		/* dgc: errors ignored here */
>  		error = xfs_qm_sync(mp, SYNC_TRYLOCK);
>  		error = xfs_sync_fsdata(mp, SYNC_TRYLOCK);
> -		if (xfs_log_need_covered(mp))
> -			error = xfs_commit_dummy_trans(mp, XFS_LOG_FORCE);
>  	}
>  	mp->m_sync_seq++;
>  	wake_up(&mp->m_wait_single_sync_task);
> 
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