CCed to openxdsm because we need extended attributes and Hans Reiser
because I know he has comments but didn't reply to your mail.
On Sun, Oct 22, 2000 at 04:23:53PM +0200, Andreas Gruenbacher wrote:
> Hello,
>
> This is a proposal to add extended attributes to the Linux kernel.
> Extended attributes are name/value pairs associated with inodes.
>
> A patch implementing extended attribute system calls, the VFS interface,
> and code for the ext2 filesystem is available. All material is GPL and/or
> LGPL licensed. The core implementation is pretty stable since months.
Did you read the thread on l-k regarding a common interface for
accessing extended attributes (much like NTFS streams)?
> New to the code base is a mechanism for sharing extended attribute blocks
> among inodes on the ext2 filesystem. This is a significant optimization.
> The block sharing code might still contain bugs. It can be deactivated at
> kernel compile time.
This is just an optimization within the filesystem transparent to VFS
and userspace, right?
So each filesystem can choose if to do this optimization, and how - for
example, for many filesystems it would make sence to make this a more
general optimization; compressing any common "objects" using the same
algorithm.
What about inheritence for extended attributes? With this code, there
are two options:
* Just setting the attribute for the directory and all subdirectories
(It get's compressed anyway...)
(not really inheritence though)
* Implement inheritence in the layers using the attributes, e.g. ACL
I don't know how much need there is for inheritence here, but if a lot
of attributes will need it I think it should be supported in the
interface instead. (though hardlinks really make this hard)
> CURRENT USES
>
> A complete and close to production quality implementation of POSIX-like
> access control lists, implemented on top of extended attributes, exists.
> This patch is maintained to be in sync with the extended attributes patch.
>
> Andrew Morgan has some code against an earlier version of the extended
> attributes patch that implements filesystem capabilities. This patch is
> out of date at the moment.
HSMs also usually need extended attributes to store data in. A common
interface to extended attributes on all linux filesystem is a
requirement for being able to implement XDSM generally for linux.
--
Ragnar Kjørstad
Big Storage
-
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to [EMAIL PROTECTED]
