linux-ext4 - Re: [PATCH] fs, dax: unify IOMAP_F_DIRTY read vs write handling policy in the dax core

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Message-ID: <20171114041228.GA4094@dastard>
Date:   Tue, 14 Nov 2017 15:12:28 +1100
From:   Dave Chinner <david@...morbit.com>
To:     Dan Williams <dan.j.williams@...el.com>
Cc:     linux-nvdimm@...ts.01.org, Jan Kara <jack@...e.cz>,
        "Darrick J. Wong" <darrick.wong@...cle.com>,
        linux-xfs@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        Ross Zwisler <ross.zwisler@...ux.intel.com>,
        linux-ext4@...r.kernel.org, Christoph Hellwig <hch@....de>
Subject: Re: [PATCH] fs, dax: unify IOMAP_F_DIRTY read vs write handling
 policy in the dax core

On Mon, Nov 13, 2017 at 05:27:54PM -0800, Dan Williams wrote:
> diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
> index b43be199fbdf..888b60189983 100644
> --- a/fs/xfs/xfs_iomap.c
> +++ b/fs/xfs/xfs_iomap.c
> @@ -1087,9 +1087,9 @@ xfs_file_iomap_begin(
>  		trace_xfs_iomap_found(ip, offset, length, 0, &imap);
>  	}
>  
> -	if ((flags & IOMAP_WRITE) && xfs_ipincount(ip) &&
> -	    (ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
> -		iomap->flags |= IOMAP_F_DIRTY;
> +	if (xfs_ipincount(ip))
> +		if (ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP)
> +			iomap->flags |= IOMAP_F_DIRTY;

Please make a helper for this, and use it in xfs_file_fsync() where
the same dirty checks are done. e.g.

static inline bool
xfs_inode_need_fsync(struct xfs_inode *ip, bool datasync)
{
	if (!xfs_ipincount(ip))
		return false;
	if (xfs_inode_clean(ip))
		return false;
	if (datasync &&
	    !(ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
		return false;
	return true;
}

Cheers,

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