Re: 2.4.17:Increase number of anonymous filesystems beyond 256?

[Pete Zaitcev <zaitcev@redhat.com>]

> From: Rainer Krienke <krienke@uni-koblenz.de>
> Date: Tue, 22 Jan 2002 16:23:54 +0100

> Thanks for the hint. I fixed pmap_create() according to your proposal and now 
> nfsd works again. 

Care to share the patch?

> Raising the count of elements of 
> unnamed_dev_in_use in fs/super.c to eg 4096 resulted in the opportunity to 
> mount as many NFS directories.

You did not send your patch (yet again), so there is no way
to tell precisely what you have accomplished. I suspect that it may
create pages with same device number that belong to different
mounts. I do not pretend to understand how VFS and page cache
use device numbers. If device numbers are used for any indexing,
pages may be mixed up with resulting data corruption.
I cannot say if this scenario is likely without looking
at the VFS code. Perhaps we ought to ask Stephen, Al, or Trond
about it.

> Why did you 
> Pete base your patch on 4 new major device numbers whereas Andis patch did 
> not need them?

He probably never tested his patch. I asked him and we'll know
soon if it was so.

-- Pete