Bug#466138: Is this LVM message actually useful?

[Andras Korn]

On Wed, Jul 08, 2009 at 06:21:27PM +0100, Alasdair G Kergon wrote:

> > ill effects and certainly doesn't warrant an obnoxious warning I can only
> > turn off by relying on an undocumented feature.
> 
> What stops you closing the fd just before the execve()?

Nothing, I suppose, other than that it adds a difficult to read line with no
obvious purpose to the script (nothing a comment couldn't explain, to be
sure). But I agree it's a workaround (whether it's nicer than the magic
envvar, I couldn't say).

> lvm will not write to pre-existing fds other than 0, 1 & 2 and lvm is currently
> imposing it as a requirement that other fds, which lvm will not use, should be
> closed before invocation.

I'm still not sure I understand why this is such a big deal that it's
unacceptable to just close them silently, but I don't want to argue this
point ad nauseam.

> > I think --quiet should get rid of these warnings too;
> 
> Unfortunately the program structure makes that impossible: these checks
> are performed during initialisation, before even looking at any command line.

Well, the fact that it's difficult to fix doesn't mean it's not broken. :)

Currently, --quiet doesn't work properly because LVM still prints messages
that aren't critical errors.

I wouldn't object to this bug being downgraded to wishlist and retitled to
something like "Please fix --quiet so that it suppresseses the warning about
FDs left open" (it's not my bug, so I won't mess with it myself). Add a
wontfix tag if you think it's never going to be fixed.

However, I think at the very least the magic envvar should be documented for
use in those cases where a stay FD is known to be present and LVM should be
silent. This would help avoid kludges like lvsomething 2>&1 | fgrep -v ...

(And hey, maybe there are even valid uses for stray FDs, only we can't think
of any right now - so that not even closing them may always be desirable.)

Andras

-- 
 Andras Korn <korn at elan.rulez.org> - <http://chardonnay.math.bme.hu/~korn/>
             Bathroom scale: Something you stand on and swear at.