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Date: Sat, 4 Dec 2004 23:27:24 +1100 (EST)
From: Bruce Evans <bde@zeta.org.au>
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To: Alfred Perlstein <alfred@freebsd.org>
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cc: Poul-Henning Kamp <phk@freebsd.org>
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cc: Jeff Roberson <jroberson@chesapeake.net>
Subject: Re: cvs commit: src/sys/kern vfs_subr.c
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On Fri, 3 Dec 2004, Alfred Perlstein wrote:

> * Jeff Roberson <jroberson@chesapeake.net> [041203 23:42] wrote:
> > On Fri, 3 Dec 2004, Nate Lawson wrote:
> >
> > > I think that breaking vprint() into multiple lines is not a good idea.
> > > Bruce pointed this out to me when I was doing the v_tag changes a while ago.
> >
> > What's the reason?
>
> possibility of it being non-atomically written to the log files?

The original reason was that log files work best with 1 line per event.
vprint() prints a label, but only for the first line so breaking the
lines breaks grepping for the label...

Atomicity isn't guaranteed, but Ian Dowse made it more likely that
single-line messages are complete if they are logged to disk at all,
by discarding truncated lines.  This doesn't work so well for
incomplete multi-line messages.

Bruce