Re: [patch 06/14] hfsplus: remove hfsplus_permission()

[Miklos Szeredi]

> >  a) it's nontrivial to fix (even understanding the problem is
> >  nontrivial, see Documentation/filesystems/directory-locking)
> 
> Please provide a concrete example, as long as I only get handwaving I can 
> only wave back.

Semi-concrete: link(2) locks the target's parent and the source.
Cross-directory rename(2) locks both parents.  If link's target is a
file which has children, this can result in an ABBA deadlock.  That's
_before_ the filesystem's ->link() or ->rename() function is called.

> >  b) the feature is obviously unused, so the easiest fix is simply to
> >  remove it for the time being.
> 
> You have a weird definition of "obviously unused", not every user may even 
> have noticed it's gone, e.g. there are some rsync versions, which support 
> this and these won't complain if they can't open the resource fork.

Dunno.  What's the difference between "it wasn't used" and "it didn't
work and nobody noticed"?  I think not much :)

Miklos
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