On Thu, Jul 15, 2021 at 02:37:52PM +1000, NeilBrown wrote: > To fix this, we need to report a different fsid for each subvolume, but > need to use the same fsid that we currently use for the top-level > volume. Changing this (by rebooting a server to new code), might > confuse the client. I don't think it would be a major problem (stale > filehandles shouldn't happen), but it is best avoided. ... > Again, we really want an API to get this from the filesystem. Changing > it later has no cost, so we don't need any commitment from the btrfs team > that this is what they will provide if/when we do get such an API. "No cost" makes me a little nervous, are we sure nobody will notice the mountd-on-fileid changing? Fileid and fsid changes I'd worry about more, though I wouldn't rule it out if that'd stand in the way of a bug fix. Thanks for looking into this. --b.
