Path: utzoo!utgpu!cunews!bnrgate!brtph3!brchh104!brchs1!bnr.ca!rice.edu!sun-spots-request
From: mario@computer-science.manchester.ac.uk
Newsgroups: comp.sys.sun
Subject: Strange TFS Behaviour
Keywords: Miscellaneous
Message-ID: <1488@brchh104.bnr.ca>
Date: 30 Jan 91 15:36:38 GMT
Sender: news@brchh104.bnr.ca
Organization: Sun-Spots
Lines: 33
Approved: Sun-Spots@rice.edu
X-Sun-Spots-Digest: Volume 10, Issue 30, message 17
X-Note: Submissions: sun-spots@rice.edu, Admin: sun-spots-request@rice.edu

I've been trying to use TFS (under 4.1.1), and it seems to behave very
strangely under some circumstances.  The main problem is that the apparent
state of a filesystem can change by unmounting and then remounting it!

Here's an eg, in which I remove a directory (and hence all its contents),
which then magically reappear again!

# mkdir /bottom /bottom/foo /top
# touch /bottom/foo/file
# mount_tfs /top /bottom  # now bottom has a layer above it..
# cd /bottom/foo
# ls
file
# rm file	# delete ("whiteout") the file
# ls		# ..apparently gone..
# lsw		# ..but still in the lower layer
file
# cd ..
# rmdir foo	# now do the same for the directory...
# mkdir foo	# ...and immediately remake it
# cd foo
# ls		# the new directory is opaque.
# cd /		# now unmount and remount the files (eg at a reboot)
# umount_tfs /bottom
# mount_tfs /top /bottom
# cd /bottom/foo 
# ls	# and the directory is now translucent, and the file has reappeared!
file

This seems just plain wrong to me.  I like the original behaviour: using
that I can have a directory which is opaque (which can be useful).  But if
opaque directories become translucent again, then I'm just going to get
confused!!