Re: TAKE - Move XFS out of the interrupt disabling game

[Christoph Hellwig <hch@infradead.org>]

On Fri, May 24, 2002 at 06:52:35AM -0500, Stephen Lord wrote:
> Thanks, you are correct (again), I flipped all this code over to
> just use spin_lock and spin_unlock. I suspect we can do away with
> most of this vfs lock code on linux actually, just a matter of thinking
> about it hard enough. It is there on Irix to prevent things happening
> to the filesystem (like unmount) during certain operations - and to
> make those operations exclusive with unmount.

On Linux makeing vfs_busycnt an atomic_t and using bitops on vfs_flag 
should allow getting rid of it.  I just wonder whether that is wanted due
to IRIX compatiblity.

> > The name suggests that it is used in IRIX to spin on a mutex_t on
> > contention, but that means it's argument is already very different on
> > Linux.  Given that fact I wonder why it is still kept for the few user.
> 
> I think the naming comes from it being a spinlock based mutual exclusion
> primitive, not that it took a mutex. It is spinlock based on Irix too.

What's the difference to the lock_t based operations then?  Maybe SGI could
submit the IRIX manpages to Wolfram Schneider <wosch@FreeBSD.org>, so they
are publically accessible at the FreeBSD hypertext manpages website
(http://www.freebsd.org/cgi/man.cgi) like many other Unix versions'Unix versions'
manpges.