On Wed, 24 Oct 2007, Oliver Fromme wrote:

Dmitry Marakasov <[EMAIL PROTECTED]> wrote:
> I was told long time ago that -ounion is even
> more broken than unionfs.

That's wrong.  The union mount option was _never_ really
broken.  I'm using it for almost as long as FreeBSD exists.

I recently noticed the following bugs in -ounion (which I've
never used for anything except testing):

(1) It is broken for all file systems except ffs and ext2fs, since
    all (?) file systems now use nmount(2) and only these two file
    systems have "union" in their mount options list.  It is still in
    the global options list in mount/mntopts.h, but this is only used
    with mount(2).  The global options list in mount/mntopts.h has
    many bogus non-global options, and even the global options list
    in kern/vfs_mount.c has some bogus non-global options, but "union"
    actually is a global options.  ext2fs loves "union" more than
    ffs -- although its options list is less disordered than ffs's,
    it has enough disorder to have 2 copies of "union".
(2) After fixing (1) by not using nmount(2), following of symlinks works
    strangely for at least devfs:
    (a) a link foo -> zero (where zero doesn't exist in the underlying
        file system) doesn't work.  mount(1) says that the lookup is
        done in the mounted file system first.
    (b) a link foo -> ./zero works.  This is correct.  Now I wonder
        if it would work if zero existed only in the underlying file
        system.

Have you noticed these bugs?  (2) is presumably old.

Bruce
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