I have some free time, and would like to spend it being paid to work for the Freenet Project, which I am informed has the funds. Previously prominent developers - oskar and tavin - have been paid $2500 for approximately 2 months work on freenet. I would like to use the same deal, and IMHO I am the only person available at the moment who has worked on the code sufficiently AND has the time for it to be practicable. I can work at least 35 hours per week, for most of the foreseeable future. In particular, I can work from immediately to 2 months later.
There are a number of major unresolved issues with freenet at the moment, but the one that has the greatest impact is probably the DataStoreBug. The problem with this, apart from the fact that I don't know fs/ very well, is that bugfixing is indeterminate. There are however some things that can be done in this direction that are reasonably determinate. For example, in order of desparation (reading the docs/source first would be a good idea, fixing them up where necessary would also be useful): a Removing all the red-black trees, and converting them to skiplists. Not as trivial as it sounds, because the nodes are mutilated. This may not solve the bug, but it should simplify the code substantially for little cost (I have heard that the worst case cost is worse with skiplists... the consensus is that it's not bad enough to be a big problem though). b Trying to prove that there is a problem with red-black trees, by making a tester that compares it with a skiplist (therefore faster than reverifying), more thoroughly. The current tests are based on special cases found while debugging the redblack tree. c Reverse engineering the accounting structures, and documenting them. d Find conditions likely to cause a DSB. Some people have reported getting it regularly. e Making the fsck etc tools work reliably, at least to detect corruption. f And to fix it, by rebuilding it. g band-aid: do a read-only check (this may take a while) when starting the node, if it's broken, try to regenerate it, if that fails, reset the store. h log all changes to the accounting tree (assuming migrating to skiplists etc hasn't fixed it), in a parsable format. Include a backtrace. Export the initial state of the tree. Checkpoint every timeperiod, either internally (more work), or by shutting it down and fsck'ing it externally. This gives us a period during which it corrupted. Then build up the tree, step by step, just as the node would have, fsck'ing after each completed change (or in a binary search, if this is computationally prohibitive, which I doubt), and find the exact instant of corruption. Then look at the backtrace, and fix the bug. This can also be converted into a regression test: run a node, checkpoint it every <moderate period of time> and fsck, keep the old state and log all changes since the clean old state along with backtraces, and email the list with a stack trace of the instant of corruption if/when we recorrupt. I am going to call this 'the nuclear option', and it requires a working accounting structures fsck and a good idea of what conditions will cause corruption; it's also probably best to try converting to skiplists first. Not knowing the code intimately, I can only give very rough estimates for the effort involved in each stage. How detailed do I need to make my proposal? Need input. -- Matthew Toseland [EMAIL PROTECTED] [EMAIL PROTECTED] Freenet/Coldstore open source hacker. Looking for $coding (I'm cheap)
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