mount option to ignore permissions

["Ihar `Philips` Filipau" <thephilips@gmail.com>]

Hi!

  [ Please CC: me, I'm not subscribed. Yet. ]

  The problem have beaten me before. And now I have it again.
  Imaging external hard drive with "proper" file system (proper ==
supports posix permissions) where files were created by user A and
then it (ext. hard drive) was brought to another location/computer and
user B tried to read them. Failure. Why? Because Linux preserved
permissions on hard drive - though they are already irrelevant on
system fs is currently mounted on. And that renders literally all
files accessible only by root.

  What is needed is special mount option to tell file system (*):
   (1) to ignore permissions when file/directory is read;
   (2) when file/directory is created it receives automatically "world
writable" permissions 0666 (I cannot imaging how to simulate "user
friendly" file attribute "read-only", though it seems not relevant to
external storage anyway).

  I'm looking into the code and it seems that every file system parses
option on their own.
  Global flags (ro/rw, nodev, etc) are handled by mount(8) itself and
passed to sys_mount() as bitmask.

  How gid/uid are passed to file system? I do not see them in
parameter list to sys_mount(). Or they are handled somehow otherwise?

  Any ideas on how I can simulate such behavior and or on how to
implement such attribute would be appreciated.

P.S. chmod/chown isn't option since (1) they do not work for ro file
system and (2) doing that every time on NNNk files might quite
tiresome - every time disk is reattached.

P.P.S. BTW MacOSX has such option and it is automatically selected for
external hard drives.

P.P.P.S. That doesn't happen with most external hard drives since they
are all FAT32. I moved to ext2/hfs+ in part to avoid the recurring
nightmares of past when I have worked with FAT32 all day long. And
also ext2/hfs+ (under Linux/MacOSX) are better than FAT*. And also I
need "case sensitiveness".

-- 
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Don't walk in front of me, I may not follow.
Just walk beside me and be my friend.
    -- Albert Camus (attributed to)