Hello everyone, My name is Hy (ugen on freenode), I am a student attending GSoC for Haiku[1]. Because I have a project that support write features for BtrFS[2], there are some questions, since the documents on wiki are not enough so I have to ask here.
1. Where can I find to read a complete btree manipulations in detail (split, insert, etc) for BtrFS except the code base ? I need to get the idea first. 2. About the reference, " ...with a refcount associated to each tree node but stored in an ad-hoc free map structure ... " - wikipedia. What is a free map structure, and where does it stored ? 3. How BtrFS allocate block and extent when cow-ed ? As I tested after making a new file, the root tree root, extent root and csum root move forward 65536 bytes, the fs root move 49152 bytes and the data extent is allocated next to the previous one. Where those numbers come from ? Is data extent is cow-ed ? I see it doesn't because extent-item still contains the old offset. 4. How BtrFS handle transactions ? Correctly me if I'm wrong, the transaction collect all requests in 30 seconds and then write back to disk. The transid increments when new request appeared and genid is asigned to this one. 5. Why there is unused space (100 bytes) at the end of each node ? 6. How does BtrFS calculate checksum ? [1]: About Haiku: www.haiku-os.org [2]: My project info on GSoC: https://summerofcode.withgoogle.com/projects/4749427110576128 Thanks, Hy -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
