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Re: [linux-lvm] NFS



On Fri, Mar 02, 2001 at 10:56:15AM +0100, Urs Thuermann wrote:
> 
> ??  Has a file system to be written so that it supports NFS?  I
> thought all file systems beneath the VFS provide the same interface to
> the NFS server and can be exported via NFS.

	NFS is such an inane sharing protocol...  It expects directories
to be arranged as if they were just a linear file of names with inode
numbers tacked on the end.  It doesn't treat them any differently than
regular files.  This causes problems with filesystems that are in
essence databases, like reiserfs.

	Reiserfs needs to generate some kind of 'position' cookie that
can be used to refind the spot in the directory that NFS was scanning.
I think the position cookie has to increase as more entries are read,
but I'm not sure.  NFS is stateless, so this position cookie has to work
for some indeterminate amount of time.

> I have also exported iso9660 and msdos file systems on local block
> devices via NFS.

	Yeah, but modeling directories in those filesystems as a string
of bytes is accurate.  You just have to have some means of magically
coming up with an inode number, and that's not too hard.  In FAT, for
example, you can just use the starting cluster number as the inode #.

Have fun (if at all possible),
-- 
The best we can hope for concerning the people at large is that they
be properly armed.  -- Alexander Hamilton
-- Eric Hopper (hopper omnifarious mn org http://www.omnifarious.org/~hopper) --

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