Hi all, This third patchset deluge is for the realtime modernization project. There are five main parts to this effort -- adding a metadata directory tree; sharding the realtime volume into allocation groups to reduce metadata lock contention; adding reverse mapping; adding reflink; and adding the one piece needed to make quotas work on realtime. This brings the robustness of the realtime volume up to par with the data volume. Originally, the modernization effort was a side project that was intended to match XFS up to the proliferation of persistent memory. The data device would store metadata on cheap(er) flash storage, and the realtime volume would be used to map persistent memory to files and take advantage of the ability to do PMD-aligned allocations. It's now less clear how much of that will actually happen (CXL?), but the code's finished, reasonably well tested, and ready for review. NOTE: I hacked up metadump to support saving the metadata contents of external logs and realtime devices so that I could run fuzz testing in the least thoughtful way possible. Chandan is working on improving the deployment image story for our customers, and will likely produce something better than my rush job. As a warning, the patches will likely take several days to trickle in. --D
