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

Alexey Dobriyan
2009-03-26T17:49:20Z

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.