Bug 150579

Version:           0.5 (using KDE KDE 3.5.7)
Installed from:    Gentoo Packages
Compiler:          gcc v4.1.2 
OS:                Linux

BTRFS is a new advanced filesystem that allows for subvolumes to be mounted to other mount points. I will use my setup as an example and even include a screenshot.

I have /dev/hda6 formatted as btrfs. Then I created three subvolumes: repos, portage_tmp, and ccache. Respectively they are mounted to /var/repos, /var/tmp/portage, and /var/tmp/ccache. You can think of subvolumes as like a completely different partition with it's own separate filesystem. The mount command for them are:
mount -t btrfs -o subvol=foo /dev/whatever /mount/point
So, I would mount one of my partitions as:
mount -t btrfs -o subvol=repos /dev/hda6 /var/repos

In fstab I have:
/dev/hda6   /var/repos   btrfs   defaults,noatime,subvol=repos 0 2
mstab shows:
/dev/hda6 /var/repos btrfs rw,noatime,subvol=repos 0 0

So, adding subvol support can be a less troubling than the other bug I posted in. :P

Basically, what I am wishing for is something like this in KDiskView:
/dev/hda6 (subvol repos) .... so on normally.
Just something to signify what subvol name I am looking at. Maybe even "btrfs subvol" in "Type", but that isn't needed. I think this would mean parsing fstab/mtab for the subvol line. I don't know if BTRFS is the only FS that has subvols, but if there are others, I think they would use this same syntax, so it would support more than just BTRFS. :)

The way subvols work, they share the same partition, unless they are given a quota. I have not set up subvol quotas yet, but I think KDF would support that automatically, because it's stored in the subvol part explicitly how big the subvol can be, like a real partition stating how big it can be.

For more info on BTRFS, you can go here:
http://oss.oracle.com/projects/btrfs/

I hope this was a clear bug report with enough information.