Date: Thu, 20 May 1999 18:43:21 -0400 From: "Chuck Youse" <cyouse@cybersites.com> To: "Ollivier Robert" <roberto@keltia.freenix.fr>, <freebsd-hackers@FreeBSD.ORG> Subject: Re: What does VOP_WHITEOUT() do? Message-ID: <002601bea312$29fae580$4d7b5ccf@f8m7n1>
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New daemon book? I must have missed that. Do you have the full title? Chuck -----Original Message----- From: Ollivier Robert <roberto@keltia.freenix.fr> To: freebsd-hackers@FreeBSD.ORG <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
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