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From: duplain@rtf.bt.co.uk (Andy Duplain)
Newsgroups: comp.unix.internals
Subject: Re: hiding files under a mount point.
Message-ID: <1991Mar19.100615.13770@rtf.bt.co.uk>
Date: 19 Mar 91 10:06:15 GMT
References: <1991Mar18.045734.5114@brolga.cc.uq.oz.au>
Organization: British Telecom Customer Systems, Brighton, UK
Lines: 24

In article <1991Mar18.045734.5114@brolga.cc.uq.oz.au> ggm@brolga.cc.uq.oz.au (George Michaelson) writes:
>
>If you have some files in a directory eg /usr (on the root partition)
>and you mount the filesystem /usr over them, they become "invisible".
>
>How "invisible" are they? Can this be exploited meaningfully by sysops
>or others to provide secure online storage of files you don't want
>mortals to know about? (/usr is a bad example. unmounting makes the
>system pretty useless. some other places might be more bearable.)

 No, they can't be used until you umount the filesystem.  We recently had a
 problem with our root disk space; we couldn't find out what was using it all
 up.  Then we realised that we had been very considerate and taken a copy
 of an old kernel, after a rebuild.  Unfortunetly we backed-up the kernel to
 /tmp, which wasn't mounted at the time.  Took ages to find the problem...
 take heed.



-- 
=== Andy Duplain ==============================================================
British Telecommunications PLC, Customer Systems, Brighton, United (?) Kingdom.
#define DISCLAIMER My views and options are not necessarily those of my company
Internet: duplain@rtf.bt.co.uk         UUCP: ...!uunet!ukc!axion!bscsq1!duplain