On Sun, 28 Dec 2008, Matthew Garrett wrote:
> Ensure relatime updates atime at least once per day
>
> 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.
>
> Signed-off-by: Matthew Garrett <mjg@xxxxxxxxxx>
> Reviewed-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
> Acked-by: Valerie Aurora Henson <vaurora@xxxxxxxxxx>
> Acked-by: Alan Cox <alan@xxxxxxxxxx>
> Acked-by: Ingo Molnar <mingo@xxxxxxx>
>
Overall I think the patch looks good.
Feel free to add
Reviewed-by: Jesper Juhl <jj@xxxxxxxxxxxxx>
if you like.
I only have a single pedantic comment below.
> ---
>
> diff --git a/fs/inode.c b/fs/inode.c
> index 0487ddb..057c92b 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -1179,6 +1179,40 @@ sector_t bmap(struct inode * inode, sector_t block)
> }
> EXPORT_SYMBOL(bmap);
>
> +/*
> + * 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;
Not all days are 24*60*60 seconds long. Daylight savings time as well as
leap seconds make this an inaccurate/incorrect constant for representing
"one day".
I don't think we really care, but perhaps the comment above should
acknowledge the fact that this is aproximately one day?
> + /*
> + * Good, we can skip the atime update:
> + */
> + return 0;
> +}
> +
> /**
> * touch_atime - update the access time
> * @mnt: mount the inode is accessed on
> @@ -1206,17 +1240,12 @@ void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
> goto out;
> if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
> goto out;
> - if (mnt->mnt_flags & MNT_RELATIME) {
> - /*
> - * With relative atime, only update atime if the previous
> - * atime is earlier than either the ctime or mtime.
> - */
> - if (timespec_compare(&inode->i_mtime, &inode->i_atime) < 0 &&
> - timespec_compare(&inode->i_ctime, &inode->i_atime) < 0)
> - goto out;
> - }
>
> now = current_fs_time(inode->i_sb);
> +
> + if (!relatime_need_update(mnt, inode, now))
> + goto out;
> +
> if (timespec_equal(&inode->i_atime, &now))
> goto out;
>
--
Jesper Juhl <jj@xxxxxxxxxxxxx>
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
Plain text mails only, please http://www.expita.com/nomime.html
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