Re: Squashfs without ./..

[ebiederm@xmission.com (Eric W. Biederman)]

Kyle Moffett <mrmacman_g4@mac.com> writes:

> Tommy Reynolds wrote:
> > Then it is broken in several ways.
> >
> > First, file systems are not required to implement ".." (only "." is
> > magical, ".." is a courtesy).
> 
> On Mar 24, 2005, at 14:59, H. Peter Anvin wrote:
> > Doesn't have anything to do with sorting order or US-ASCII, it has to
> > do with readdir order.  If nothing else, it would be highly surprising
> > if "." and ".." weren't first; it's certainly a de facto standard, if
> > not de jure.
> 
> IMHO, this is one of those cases where "Be liberal in what you accept
> and strict in what you emit" applies strongly.  New filesystems should
> probably always emit "." and ".." in that order with sane behavior,
> and new programs should probably be able to handle it if they don't. I
> would add ".." and "." to squashfs, just so that it acts like the rest
> of the filesystems on the planet, even if it has to emulate them
> internally.  OTOH, I think that the default behavior of find is broken
> and should probably be fixed, maybe by making the default use the full
> readdir and optionally allowing a -fast option that optimizes the
> search using such tricks.

Find is doing a full readdir.  It just looks at the link count
of the directory it is doing the readdir on and if it is the
minimal unix link count of 2 it knows it does not have to stat
directory entries to see if they are directories.

As I recall there is also special handling in find for link count
of 1 to automatically handle filesystems that don't follow the normal
unix conventions so every directory entry must be stated.

Eric