Re: [PATCH] Allow relatime to update atime once a day

[Alexey Dobriyan]

On Thu, Mar 26, 2009 at 05:32:14PM +0000, Matthew Garrett wrote:
> Allow atime to be updated once per day even with relatime. This lets
> utilities like tmpreaper (which delete files based on last access time)
> continue working, making relatime a plausible default for distributions.

> +/*
> + * With relative atime, only update atime if the previous atime is
> + * earlier than either the ctime or mtime or if at least a day has
> + * passed since the last atime update.
> + */
> +static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
> +			     struct timespec now)
> +{
> +
> +	if (!(mnt->mnt_flags & MNT_RELATIME))
> +		return 1;
> +	/*
> +	 * Is mtime younger than atime? If yes, update atime:
> +	 */
> +	if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0)
> +		return 1;
> +	/*
> +	 * Is ctime younger than atime? If yes, update atime:
> +	 */
> +	if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0)
> +		return 1;
> +
> +	/*
> +	 * Is the previous atime value older than a day? If yes,
> +	 * update atime:
> +	 */
> +	if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
> +		return 1;
> +	/*
> +	 * Good, we can skip the atime update:
> +	 */
> +	return 0;
> +}

Good example of overcommented code.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/