Mitch Harder wrote: > On Mon, Oct 25, 2010 at 9:34 PM, Li Zefan <lizf@xxxxxxxxxxxxxx> wrote: >> Chris Mason wrote: >>> On Mon, Oct 25, 2010 at 03:11:22PM +0800, Li Zefan wrote: >>>> Lzo is a much faster compression algorithm than gzib, so would allow >>>> more users to enable transparent compression, and some users can >>>> choose from compression ratio and compression speed. >>> This is also much smaller than I expected, really nice. It looks like >>> older kernels won't properly deal (nicely give EIO) with lzo compressed >>> files? >>> >>> We can add compatbits to deal with that if it is the case. >>> >> I forgot compatibility issue with older kernels.. >> >> Though I didn't test older kernels, I don't think they can deal with lzo >> compressed files properly, at least not for inlined extents, in which >> case I think btrfs will just show compressed data to the users. >> >> So yes, an incompat flag is needed. > > I've been testing this set of patches on a 2.6.36 kernel with the > latest btrfs-unstable patches, and I wanted to provide my positive > feedback. > > The lzo compression patches worked as expected, and I did not > encounter any stability problems in my testing (which mainly consisted > of decompressing a root partition archive and doing some compiling > chores in a chroot environment on that drive). > > I did some crude benchmarking on decompressing an archived root > partition to an empty btrfs drive, and my results were similar to the > results posted by Li Zefan in the original post. The lzo compression > did not compress quite as well as zlib, but was much faster. > > I did some test mounting of a lzo-compressed partition with an older > non-lzo-patched kernel, and as expected, the contents of the files > were garbled. But I did not encounter kernel oops or other issues > when trying to read the garbled files. > > I also wanted to confirm that my other zlib-compressed partitions did > not encounter any issues when bouncing back and forth between a > lzo-patched kernel and older kernels. As expected, I did not see any > issues in the partitions that had only been mounted with zlib > compression. > > You'll want an incompat flag as indicated in previous posts, but I > look forward to seeing lzo compression in the future. > Thanks for testing! I had been occupied by other things, so have been silent on this. Actually I've added the incompat flag, but haven't done userspace programs. I'm setting up a git tree, and will send out a pull request to Chris this week. (probabaly) And I think I can add your Tested-by in the whole patchset? Except for the ioctl change, which I guess you didn't test. We really need more review and test for btrfs patches, so what you've done is really appreciatated. :) -- Li Zefan -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
