bug or feature?

Chris Ricker (kaboom@gatech.edu)
Sun, 14 Feb 1999 17:26:38 -0500 (EST)


I just noticed the following:

It seems Linux will let you mount "over" NFS mounts. For example (pynchon
is running 2.2.1 and using knfs, bofh is uid 0 ;-):

[bofh@pynchon /mnt]# ls dobzhansky/
FreeBSD cdrom kaboom tmp
build emulation mozilla updates
[bofh@pynchon /mnt]# mount | grep dobzhansky
dobzhansky:/tmp on /mnt/dobzhansky/tmp type nfs
(rw,rsize=8192,wsize=8192,soft,addr=)
dobzhansky:/home/kaboom on /mnt/dobzhansky/kaboom type nfs
(rw,rsize=8192,wsize=8192,soft,addr=)
dobzhansky:/build on /mnt/dobzhansky/build type nfs
(rw,rsize=8192,wsize=8192,soft,addr=)
dobzhansky:/opt/emulation on /mnt/dobzhansky/emulation type nfs
(rw,rsize=8192,wsize=8192,soft,addr=)
dobzhansky:/opt/mozilla on /mnt/dobzhansky/mozilla type nfs
(rw,rsize=8192,wsize=8192,soft,addr=)
dobzhansky:/opt/updates on /mnt/dobzhansky/updates type nfs
(rw,rsize=8192,wsize=8192,soft,addr=)
dobzhansky:/opt/FreeBSD on /mnt/dobzhansky/FreeBSD type nfs
(ro,rsize=8192,wsize=8192,addr=)
[bofh@pynchon /mnt]#

So, I've got a bunch of stuff NFS mounted from dobzhansky under
/mnt/dobzhansky/ on pynchon.

Now, I mount over them:

[bofh@pynchon /mnt]# mount -t ext2 /dev/fd0 /mnt/dobzhansky
mount: block device /dev/fd0 is write-protected, mounting read-only
[bofh@pynchon /mnt]# ls dobzhansky/
lib lost+found pcmcia.cgz tmp usr
[bofh@pynchon /mnt]#

Shouldn't I instead get an error about "/mnt/dobzhansky busy" or something
like that? That's what happens under Solaris 2.7 and FreeBSD 4.0 (those
being the other unixen I have at home to try this with)....

later,
chris

--
Chris Ricker                                            kaboom@gatech.edu
                                               chris.ricker@m.cc.utah.edu
Work was impossible.
The geeks had broken my spirit.
They had done too many things wrong.
	-- Hunter S. Thompson, _Generation of Swine_

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