Re: [PATCH] Update atime from future.

From: Zach Brown
Date: Tue Dec 04 2012 - 14:41:02 EST


On Tue, Dec 04, 2012 at 01:56:39AM +0800, yangsheng wrote:
> Relatime should update the inode atime if it is more than a day in the
> future. The original problem seen was a tarball that had a bad atime,
> but could also happen if someone fat-fingers a "touch". The future
> atime will never be fixed. Before the relatime patch, the future atime
> would be updated back to the current time on the next access.

I guess.

> /*
> + * Is the previous atime value in future? If yes,
> + * update atime:
> + */
> + if ((long)(now.tv_sec - inode->i_atime.tv_sec) < -RELATIME_MARGIN)
> + return 1;

But this is confusing to read. "If atime is less than a negative day in
the past.. wait, what?"

It seems like we should combine the two RELATIME_MARGIN tests.

/*
* Update atime if it's older than a day or more than a day
* in the future, which we assume is corrupt.
*/
if (abs(inode->i_atime.tv_sec - now.tv_sec)) >= RELATIME_MARGIN)
return 1;

(I don't know if you'd still need the (long) cast in there, given the
type tests in abs()).

- z
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