Re: Ext3 filesystem info?

Jesse Pollard (pollard@tomcat.admin.navo.hpc.mil)
Wed, 22 Sep 1999 08:01:17 -0500 (CDT)


From: "Theodore Y. Ts'o" <tytso@mit.edu>
>From: Jeff Haumont <haumont@acm.org>
>
> The common interface wouldn't have to try to use every feature of the
> ACLs in the underlying filesystem. Even a least-common-demoninator
> interface would be much better than nothing. Maybe restrict to
> directory ACLs only, etc.
>
>The problem is that systems that use per-file ACL's are very different
>from systems that use directory ACL's --- apples and oranges. You can't
>map one to the other; there is no least common denominator.

Hmm. How many different classes are there?
POSIX - NTFS (should be), IRIX/Unicos, Solaris, HPUX
Directory only - AFS/DFS, (does the Andrew FS fit here)?
others?
no acls - FAT16/32 ?

How many would have to be supported... How about supporting POSIX, and
possibly one other...?

Granted - one option is emulating ACLs in a file system that doesn't natively
support them is possible. One approach is to allow the FS implementation to
use a "reserved" file to store ACL information. This file might not be
available to users of Linux, but would allow for ACLs. I would not reccommended
it for removable media, since the media could be taken to a non-linux OS and
bypassed. Of course - physical possession of media invalidates the ACLs
anyway.
-------------------------------------------------------------------------
Jesse I Pollard, II
Email: pollard@navo.hpc.mil

Any opinions expressed are solely my own.

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