Re: some project ideas: NFS4 ACLs, resilience on the same device, allowing to specify which devices are "distinct" in a RAID

[Goffredo Baroncelli <kreijack@libero.it>]

On 06/02/2014 07:44 PM, Christoph Anton Mitterer wrote:
> Hi.
> 
> Christian Kujau suggested in the wiki[] to post project ideas to the
> list to give them some possible wider discussion.
> 
> So far I've had these ideas:
> 
> 1) NFS 4 ACLs[1]
> Not sure whether it has been proposed and/or rejected before),... but it
> would be nice if it was a goal for btrfs to support NFS4 ACLs.
> 
> These are much more powerful than POSIX.1e ACLs... and I think it would
> be nice if all the major Linux filesystems would support them in
> addition or as an alternative to the POSIX.1e ACLs. Of course one would
> have to think about a schema what happens when there are ACLs of both
> types in place for a file, whether this is allowed at all or not and how
> rules would be merged.

There is (was ?) a project to address that: richacl http://www.bestbits.at/richacl/.
This is not a btrfs project, but a linux kernel project because from a filesystem  POV the implementation requires to store some information in a extended attributes: the check is performed at the VFS level.

[...]
> 
> 
> 3) allow to tell btrfs which devices are really distinct in a RAID
> For some reasons people may have setups e.g. like this:
> /dev/sda1
> /dev/sda2
> /dev/sdb1
> /dev/sdc1
> Now one could create a RAID5 on them, but apparently sda1 and sda2 are
> on the same disk... so I'd like a way to tell btrfs that these are the
> "same" and not really that redundant.

Hugo Mill worked on something related to that [1]

[1] "Thoughts on RAID nomenclature" http://www.spinics.net/lists/linux-btrfs/msg33782.html

> 
> 
> Cheers,
> Chris.
> 
> [0] https://btrfs.wiki.kernel.org/index.php?title=Talk%3AProject_ideas&action=historysubmit&diff=26841&oldid=26831
> [1] https://btrfs.wiki.kernel.org/index.php/Talk:Project_ideas#NFS4_ACLS
> 


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