From owner-freebsd-current  Sat May 18 16:55:31 2002
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Date: Sat, 18 May 2002 16:54:51 -0700
From: Terry Lambert <tlambert2@mindspring.com>
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To: Ian Dowse <iedowse@maths.tcd.ie>
Cc: Ian <freebsd@damnhippie.dyndns.org>,
	freebsd-current <freebsd-current@freebsd.org>
Subject: Re: df
References: <200205190041.aa04845@salmon.maths.tcd.ie>
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Ian Dowse wrote:
> In message <3CE6DFED.8604C72C@mindspring.com>, Terry Lambert writes:
> >I think the reason for the "if" is to keep the df from hanging
> >indefinitely, particularly when you give it an explicit list.
> 
> No, I believe the "if (vfslist != NULL)" code was there to reduce
> the maximum column widths to those necessary for an explicit list
> of filesystems rather than using the maximum widths for all
> filesystems. The regetmntinfo() call before the "if" has already
> performed any operations that could hang indefinitely, so it makes
> sense to unconditionally use these up-to-date results instead of
> the potentially stale list from getmntinfo(..., MNT_NOWAIT).

Like "ps", "df" is a snapshot.

As such, "staleness" after a few tenths of a second is really
irrelevent, since the information is never really "the real
and precise information".

It's more important to be able to get information in a misbehaving
system, without hanging your shell forever.  8-(.

-- Terry

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