Date: Thu, 4 Nov 1999 23:39:22 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: grog@lemis.com Cc: don@calis.blacksun.org, freebsd-fs@FreeBSD.ORG Subject: Re: Features of a journaled file system Message-ID: <199911042339.QAA21054@usr07.primenet.com> In-Reply-To: <19991102102601.54815@mojave.sitaranetworks.com> from "Greg Lehey" at Nov 2, 99 10:26:01 am
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> On Saturday, 30 October 1999 at 18:56:24 -0400, Don wrote: > > What are the features people would like to see in a new FreeBSD file > > system? Some of the ones I have heard listed are: > > 1. Ability to grow a FS > > 2. Ability to shrink a FS > > 3. Acess control lists on files and file systems > > 4. Extensibility. (The ability to easily add new features to the > > filesystem without having to rewrite utilities such as fsck) > > None of these are specific features of a journalling file system. > They're probably all desirable. ACLs, in particular, should not be a feature of an FS that manages block allocation policy, but should instead be a semantic access stacking layer. It is trivial to write an ACL (or quota) stacking layer, given working stacking layers. I think that requests like ACLs, extended attributes, user and group disk quotas, NT security policy management, etc., etc., should all go on the "make stacking layers work" list, _not_ the "write a journalled FS" list. That said, a journalled FS would be a useful thing to have, and not just for the marketing bullet item. I am thinking in particular about how very easy it would be to implement a userland accessibly transactioning system and record based file layout semantics with such a beast... 8-). I also like the idea of re-seperating the UFS and FFS layers, so that you could initially work on just the journalling issues, and we could tackle b-tree based directory management (for example) in a seperate stacking layer... just like the UFS stacking layer does by overlaying an alphabetic name, link, and symlink supporting semantics ontop of the FFS namespace, which is basically a flat numberic namespace that knows how to do block management in numerically (inode number) named objects. 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
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