Date: Sun, 17 Sep 2000 19:16:42 -0500 (CDT) From: Mike Meyer <mwm@mired.org> To: Greg Lehey <grog@lemis.com> Cc: questions@freebsd.org Subject: Re: Advanced File System on FreeBSD Message-ID: <14789.24298.915594.24401@guru.mired.org> In-Reply-To: <20000918074748.F67912@wantadilla.lemis.com> References: <121596976@toto.iv> <14789.649.22564.273240@guru.mired.org> <20000918074748.F67912@wantadilla.lemis.com>
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Greg Lehey writes: > >>> What happens if you have: > >>> /a/b/c and /a/b/d hard linked to each other, then you delete and > >>> undelete /a/b/c? You get the contents back, but lost the benefit of > >>> the hard link, and when you change /a/b/d and /a/b/c doesn't change, > >>> you get a nasty surprise. > >> No, you'd have to remember that sort of thing. It's not difficult. > > How about this scenario. a/b/c and a/b/d are hard links. I unlink > > a/b/c. I then change a/b/d without changing the inode number (a), > > unlink it (b), and create a new a/b/d with a new inode number > > (c). What would I get back if I undeleted a/b/c at each of the times > > labeled (a), (b), and (c) - and why? > You would have to have the choice. If at point (c) you decide you > need the old inode, you'd need to find a way to get it. Of course, > you're getting into a more general (and expensive) change management > system here. Yup, that's much more expensive. But those issues still need to be dealt with. > >> Years ago I ran Interactive UNIX System V.3, and I installed the > >> Norton Utilities for System V (yes, there was such a thing), which > >> included undelete. I don't think I ever used it. I also think that > >> the main thing stopping an implementation is that the people who could > >> implement it don't want it. > > Actually, there is a time when the people who could implement it do > > want it. That's when they are dealing with lots of newbies, and don't > > want to be bothered with requests to recover accidently deleted files > > from backups. > I think you're looking at the "sysadmin for a large UNIX installation" > scenario here. Nowadays it's more likely to be "I just deleted all my > files, how do I get them back?" question, to which the hardened hacker > replies "read them in from last night's backup". That's easier than > writing complicated software. True - the people who wrote the scripts were dealing with a large installation. Of course, these days they're liable to have used KDE or some such to delete the files instead of rm, as you mentioned. Possibly those applications need to be enhanced for this? Of course, on *this* list we get newbie sysadmins who need that help, and nothing but a file system that does "the right thing" by default is going to save them. > > Doing the script for rm solves that problem, and is much easier. > Well, why don't you do it, then? Because I don't have those newbie users. I also have 1) automated nightly backups and 2) an expensive change control system, which goes a long way to alleviate the need for such a thing. Of course, my coding skills are negotiable if someone wants one bad enough. <mike To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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