Friday, 29 October 2010


So the one line bug in BFS 357 is big enough that it may affect anyone with an Intel wireless containing laptop or similar. How do I know this? Well I hit it on my own laptop. I hit it on suspend after about 30 suspend to ram cycles. Nothing better than a big fat OOPS on your own hardware to make you feel obliged to update your own code. So given that 2.6.36-ck1 is barely one week old, and 2.6.36 is likely to be the "stable" 3 point release for 3 months, I've decided to release 2.6.36-ck2 with just one line of code changed. As per my last blog entry, I've just removed one BUG_ON which would cause an oops on BFS 357 when it's run on a 2.6.36 kernel. If you're not hitting this bug, there is no point whatsoever to upgrade from ck1 to ck2. For my own internal testing I'm using a WARN_ON_ONCE in place of the BUG_ON, to see if there's something meaningful in the bug that's a mainline problem, but it's safe to just remove this OOPS for everyone else.

Get it here either as a full patch or split out patches:

I've also updated the BFS 357 patch on my website with the one line fix, and given that it's still the same BFS otherwise, all I've done is change the filename rather than bump the BFS version number.

Get it here:

On an unrelated note, I finally got off my arse and fixed the long-standing install bug if DESTDIR was set on lrzip, which was a two line fix and reported by about a billion different people. I bumped the version up to 0.47 without any other changes.

lrzip on freshmeat

I've been looking at the lrzip code recently just for a change of pace. One of the things that bugged me about it is that I upgraded it a while back to truly be 64 bit in that it accepts 64 bit sized files, and can make the most of all ram on any sized 64 bit machines, but that caused regressions in file compression sizes and speed. What this means long term is that as file sizes get bigger, and machines get more and more ram, the compression of lrzip will get more and more impressive. However the reason it bugs me is that all that 64 bit addressing costs a lot in space. So I'm working on a scaled bitsize compression format for the next version now, which will only use as many bits as the compression window is. I've seen some modest improvements only, but they're worthwhile chasing. More on that front if I make progress soon.


  1. About lrzip, how does it fare now when compared to XZ Utils ( which has gone stable recently?