On Mon, Sep 05, 2022 at 02:59:33PM +0800, Qu Wenruo wrote: > Mostly due to the fact that metadata and data go split ways for > verification. > > All the verification for data happens at endio time. Yes. > While part of the verification of metadata (bytenr, csum, level, > tree-checker) goes at endio, but transid, checks against parent are all > done at btrfs_read_extent_buffer() time. > > This also means, the read-repair happens at different timing. Yes. read-repair for metadata currently is very different than that from data. But that is something that exists already in is not new in this series. > But what about putting all the needed metadata info (first key, level, > transid etc) also into bbio (using a union to take the same space of > data csum), so that all verification and read repair can happen at endio > time, the same timing as data? I thought about that. And I suspect it probably is the right thing to do. I'm mostly stayed away from it because it doesn't really help with the goal in this series, and I also don't have good code coverage to fail comfortable touching the metadata checksum handling and repair. I can offer this sneaky deal: if someone help creating good metadata repair coverage in xfstests, I will look into this next.
