From owner-freebsd-fs Fri Aug 7 00:28:16 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id AAA15880 for freebsd-fs-outgoing; Fri, 7 Aug 1998 00:28:16 -0700 (PDT) (envelope-from owner-freebsd-fs@FreeBSD.ORG) Received: from smtp03.primenet.com (smtp03.primenet.com [206.165.6.133]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id AAA15796 for ; Fri, 7 Aug 1998 00:28:08 -0700 (PDT) (envelope-from tlambert@usr08.primenet.com) Received: (from daemon@localhost) by smtp03.primenet.com (8.8.8/8.8.8) id AAA28917; Fri, 7 Aug 1998 00:27:47 -0700 (MST) Received: from usr08.primenet.com(206.165.6.208) via SMTP by smtp03.primenet.com, id smtpd028874; Fri Aug 7 00:27:37 1998 Received: (from tlambert@localhost) by usr08.primenet.com (8.8.5/8.8.5) id AAA22692; Fri, 7 Aug 1998 00:27:35 -0700 (MST) From: Terry Lambert Message-Id: <199808070727.AAA22692@usr08.primenet.com> Subject: Re: inode version? To: poipoi@famipow.com Date: Fri, 7 Aug 1998 07:27:34 +0000 (GMT) Cc: freebsd-fs@FreeBSD.ORG In-Reply-To: <19980807061557.268.qmail@hwi.poi.org> from "poipoi@famipow.com" at Aug 7, 98 08:15:57 am X-Mailer: ELM [version 2.4 PL25] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > in vfs implementation, i see a inode version but i dont understand what > is it... according to some books, it is used for NFS but i understand > how and why. It is used to tell the difference between an inode that is rereferenced in a stateless protocol and an inode that is rereferenced after it has been reused. If it has been reused, it's just as valid as before, but if the generation count is different, it's stale. This is used to recover from the case where an inode reference count goes to zero on an NFS server when the file is held open over a delete. Because you can't set VEXEC on the server from the client, in a memory overcommit architecture (where the file is used as a swap store), a file may "disappear" out from under you. If this happens, the generation number changes, and you can tell that it happened, and fail more gracefully than you would have oherwise. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message