Bug#553707: RFH: lzma -- future of Debian squashfs-lzma
I was thinking about how to bring the lzma package more up to date,
but I’m scared to do anything for fear of breaking squashfs-lzma. :)
So I thought I’d write for advice.
squashfs is a read-only compressed filesystem. Currently a kernel
module for reading LZMA-compressed squashfs 3.x is packaged for Debian
through the lzma source package. I think the userspace support is in
squashfs-tools, though I’m not sure since I’ve never tried it.
Good news: squashfs maintainer Phillip Lougher is pushing for
LZMA support in squashfs 4.0 in the mainline kernel v2.6.33 or so. 
Packaging this for Debian would perhaps mean backporting the change
for the linux-2.6 package and making sure the squashfs-tools package
has the appropriate support.
1. How to support current users until an updated kernel enters sid?
Should the lzma package have to continue to produce an lzma-source
I am not excited about making sure this still works with each LZMA
SDK upgrade. squashfs-lzma upstream used to just pick one version
to support (now the version in the mainline kernel is used), and
I’m afraid having to rebase the patch for each release would slow
things down a lot.
2. Once squashfs 4 + lzma is available, is there a need to continue
to support squashfs 3 + lzma?
I am hoping not, because it is not clear the current kernel
patches apply to recent kernels. But if there is, we can probably
find some way.
3. More generally, what do people use squashfs-lzma for, and what
guarantees do they need in order to do it?
I am hoping some squashfs-lzma user can explain how and perhaps take
on the task of assuring it is well supported for squeeze. But there
is plenty to do short of that, and I would be glad to help your
efforts in any way I can.