From owner-freebsd-hackers Tue Dec 4 12: 2:59 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from gw.gbch.net (gw.gbch.net [203.143.238.93]) by hub.freebsd.org (Postfix) with SMTP id 927D437B41A for ; Tue, 4 Dec 2001 12:02:51 -0800 (PST) Received: (qmail 54799 invoked by uid 1001); 5 Dec 2001 06:02:49 +1000 X-Posted-By: GJB-Post 2.23 27-Nov-2001 X-Operating-System: FreeBSD 4.2-RELEASE i386 X-Uptime: 14:11 X-Location: Brisbane, Australia; 27.49841S 152.98439E X-URL: http://www.gbch.net/gjb.html X-Image-URL: http://www.gbch.net/gjb/gjb-auug048.gif X-GPG-Fingerprint: EBB2 2A92 A79D 1533 AC00 3C46 5D83 B6FB 4B04 B7D6 X-PGP-Public-Keys: http://www.gbch.net/keys.html Message-Id: Date: Wed, 05 Dec 2001 06:02:49 +1000 From: Greg Black To: Matthew Dillon Cc: Ian Dowse , Bernd Walter , cjclark@alum.mit.edu, Mark Hannon , bugs-followup@FreeBSD.ORG, hackers@FreeBSD.ORG Subject: Re: bin/32261: dump creates a dump file much larger than sum of dumped files References: <200112041339.aa05506@salmon.maths.tcd.ie> <200112041957.fB4Jv1j20226@apollo.backplane.com> In-reply-to: <200112041957.fB4Jv1j20226@apollo.backplane.com> of Tue, 04 Dec 2001 11:57:01 PST Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Matthew Dillon wrote: | :In message <20011204135626.A75212@cicely8.cicely.de>, Bernd Walter writes: | :>> Is there any reason we don't want to truncate the file? Does O_TRUNC | :>> not work well of the file is a tape device or something? | :> | :>I don't expect O_TRUNK to work on devices such tapes and disks. | : | :Well, it won't achieve anything on tapes or disk devices, but it | :should be completely harmless to add the O_TRUNC flag. The current | :behaviour is likely to be unexpected and cause confusion so it | :might as well be changed. I'll commit this later unless someone | :can think of a good reason not to. | : | :Ian | | Woa! That sounds like a bad idea to me. If you want to do it right | then open(), fstat(), and only if the stat says it is a regular file | do you then ftruncate(). Passing O_TRUNC to a tape device may be ignored | by us, but it's not a valid flag to pass to a tape device and we shouldn't | do it. I haven't used any of them for a while, but there are certainly Unix systems that treat O_TRUNC as a signal to rewind a tape device before writing to it. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message