I had read the man page, but none of my key partitions is mounted with a bind option, and so the bind mount exclusion did not seem to apply.
Could you add a warning, like "btrfs may accomplish a subvolume mount with a bind mount even if you do not explicitly request it." Also, it would be nice to have an explanation of the --debug-pruning output. I did disable pruning of bind mounts, and had already added the duplicate paths to PRUNEPATHS. Now update/locate seem to be operating as I wanted. And it's incredibly fast: 28 seconds for my terabytes of disk space. Nice job!
