Re: Thinking outside the box on file systems

From: Michael Tharp
Date: Wed Aug 15 2007 - 11:14:47 EST


Kyle Moffett wrote:
> Basically any newly-created item in such a directory will get the
> permissions described by the "default:" entries in the ACL, and
> subdirectories will get a copy of said "default:" entries.

This would work well, although I would give write permissions to a group
so the entire dir wouldn't need to be re-ACLed when a user is added. I
may give this a shot; I've been avoiding ACLs because they have always
sounded incomplete/not useful, but the inheritance aspect sounds rather
nice.

> So yes, such functionality is nice; even more so because we already have
> it. I think if you were really going to "extend" a UNIX filesystem it
> would need to be in 2 directions:
> (A) Handling disk failures by keeping multiple copies of important
> files.

This is ZFS' bailiwick, no? I'd love to see the licensing issues
resolved, because if it can control level of redundancy on a
per-file/directory basis, I would be a very happy man.

> (B) Have version-control support

This might be pushing it, but hey, we *are* talking about the future here.

> (C) Allowing distributed storage (also lazy synchronization and
> offline modification support)

I'd really love to see distributed storage not suck. Everything I've
seen requires myriad daemons and ugly configuration.

> With some appropriate modifications and hooks, GIT actually comes pretty
> close here. For larger files it needs to use a "list-of-4MB-chunks"
> approach to minimize the computation overhead for committing a
> randomly-modified file. The "index" of course would be directly read
> and modified by vfs calls and via mapped memory. Merge handling would
> need careful integration, preferably with allowing custom
> default-merge-handlers per subtree. There would be lots more design
> issues to work out, but it's something to think about

Now you're just being silly ;)

> Cheers,
> Kyle Moffett

-- m. tharp
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