From owner-freebsd-hackers Sat Apr 24 6:10:44 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from sol (cs1-gw.cs.binghamton.edu [128.226.171.72]) by hub.freebsd.org (Postfix) with SMTP id 4774114CBB for ; Sat, 24 Apr 1999 06:10:43 -0700 (PDT) (envelope-from zzhang@cs.binghamton.edu) Received: from localhost (zzhang@localhost) by sol (SMI-8.6/8.6.9) with SMTP id JAA13550 for ; Sat, 24 Apr 1999 09:00:24 -0400 Date: Sat, 24 Apr 1999 09:00:23 -0400 (EDT) From: Zhihui Zhang To: freebsd-hackers@freebsd.org Subject: Logical block number caching Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG The 4.4BSD book says the following on page 227: The drawback to using a *logical* address cache is that it is difficult to detect aliases for a block belonging to a local file and the same block accessed through the block device disk whose logical block address is the same as the physical block address. The kernel handles these aliases by administratively preventing them from occuring. The kernel does not allow the block device for a partition to be opened while that partition is mounted and vice versa. Is this the same situation with FreeBSD 3.1? I have tried to find where in the source code this gets handled without luck. I hope someone will tell me whether FreeBSD uses the same strategy and which routines handle this. Any help is appreciated. -------------------------------------------------- Zhihui Zhang. Please visit http://www.freebsd.org -------------------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message