From owner-freebsd-hackers Thu May 20 15:45:35 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from nero.cybersites.com (nero.cybersites.com [207.92.123.21]) by hub.freebsd.org (Postfix) with ESMTP id 18E0B154AA for ; Thu, 20 May 1999 15:45:28 -0700 (PDT) (envelope-from cyouse@cybersites.com) Received: from f8m7n1 (dhcp77.cybersites.com [207.92.123.77]) by nero.cybersites.com (8.8.7/8.8.7) with SMTP id RAA06950; Thu, 20 May 1999 17:51:18 -0400 Message-ID: <002601bea312$29fae580$4d7b5ccf@f8m7n1> From: "Chuck Youse" To: "Ollivier Robert" , Subject: Re: What does VOP_WHITEOUT() do? Date: Thu, 20 May 1999 18:43:21 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.1 X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG New daemon book? I must have missed that. Do you have the full title? Chuck -----Original Message----- From: Ollivier Robert To: freebsd-hackers@FreeBSD.ORG Date: Thursday, May 20, 1999 5:32 PM Subject: Re: What does VOP_WHITEOUT() do? >According to Zhihui Zhang: >> Can anyone tell me what does VOP_WHITEOUT() do? I can not find it in the >> hypertext manual pages. > >You can find a small documentation in the 4.4BSD daemon book. It is used when >stacking filesystems (especially unionfs). > >Imagine you have 2 FS mounted on above the other with unionfs. This gives you >FS1. Note that when stacking FS, the underlying ones are R/O (FS2 in this >case). > >FS "file A" it appears here. > 1 >--------------------- >FS ---> file A the real file > 2 > >File A is seen as part of the whole unified FS1. Now, imagine you "rm" file A >from FS1. The file won't be actually removed from FS2 but a "whiteout" entry >will appear inside FS1 to "mask" the file from it. > >More (and better) explanations on page 236 of the new daemon book. >-- >Ollivier ROBERT -=- FreeBSD: The Power to Serve! -=- roberto@keltia.freenix.fr >FreeBSD keltia.freenix.fr 4.0-CURRENT #71: Sun May 9 20:16:32 CEST 1999 > > > >To Unsubscribe: send mail to majordomo@FreeBSD.org >with "unsubscribe freebsd-hackers" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message