In message <[EMAIL PROTECTED]>, [EMAIL PROTECTED]
writes:
[...]
> so mount could keep a /etc/mtab2 to record this informatoin, but that's
> freaking ugly. or we could pass a new mount option down into the kernel
> which causes it to display `loop' in that entry, bu this seems like a
> waste of a bit. other alternatives gladly sought.
Not necessarily. Several OSs use an "ignore" bit as a mount flag telling
programs like df(1) not to stat certain entries by default. This is often
used for automounted/autofs entries, where normally no reasonable info can
be returned to statvfs(2), plus it's a good idea not to slow df(1) by
stating file systems that may be served by slow user-level file servers (amd
w/o autofs support). There are cases where such file servers can return
useful info back to statvfs(2) (as amd can).
BTW, the usual reason you don't see such automounted entries is that GNU df
automatically will not list entries with statfs values of 0, but it still
will statfs(2) them which will be slow (and hand if the automounter is
hung). It's much better if the kernel can record that certain entries were
mounted w/ the "ignore" option, and ensure that df(1) simply doesn't
statfs's 'em at all.
Erez.
