Date: Wed, 12 Jul 2000 17:28:35 +0200 (CEST) From: Marius Bendiksen <mbendiks@eunet.no> To: Kelly Yancey <kbyanc@posi.net> Cc: Dmitry Brodsky <dima@cs.ubc.ca>, freebsd-fs@FreeBSD.ORG Subject: Re: Meta-Data & stackable FS Message-ID: <Pine.BSF.4.05.10007121722420.6345-100000@login-1.eunet.no> In-Reply-To: <Pine.BSF.4.21.0007112346510.39799-100000@gateway.posi.net>
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> So long as you only stack over FFS. As much as I like the idea of extended > attributes, stacked file systems should be able to stack over any other > filesystem. Absolutely not. A stacked layer to provide EAs should be added, and all future layers should assume that EA capability is present. This way, we keep things nice and tidy. What on Earth would be the point of adding a new feature like EAs if it is only going to remain unused? > Unless I'm mistaken, NFS doesn't support EA's, not to mention any > of the misc. filesystems. I don't even know where one would begin trying to > add EA support to say, procfs. Procfs isn't persistent in the first place. And, as to NFS, that would be resolved by the use of a stacked layer to actually *provide* EAs. > But the man page touches on this, and other valid converns: [snip] > How could you possibly build a stackable filesystem using EA's when there > are so many unknowns except for the degenerate case of "you can stack this > filesystem over FFS, or you can't stack it anywhere". By adding a stacked layer which translates the semantics of an underlying filesystem, or adds it, if it is not present, you resolve this issue. Further, EA support is entering into many of the new filesystems appearing, including old ones like ext2fs, ffs, xfs, jfs, and hpfs. > And that doesn't even touch the fact that even with FFS, other filesystems > can trample on EA's required by your filesystem. The ideas behind EA's are > noble, but I can't see using EA's in practice. :( This has to do with the authentication mechanism provided. If you make the suser() call always return 0, then you will have any user capable of doing evil things to your filesystem. Same thing here. You need authentication. Robert is already using EAs to add ACL support. Mariyus To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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