On Tue, 7 Jan 2020, Chris Mason wrote: > On 7 Jan 2020, at 16:07, Dave Chinner wrote: > > > IOWs, there are *lots* of 64bit inode numbers out there on XFS > > filesystems.... > > It's less likely in btrfs but +1 to all of Dave's comments. I'm happy > to run a scan on machines in the fleet and see how many have 64 bit > inodes (either buttery or x-y), but it's going to be a lot. Dave, Amir, Chris, many thanks for the info you've filled in - and absolutely no need to run any scan on your fleet for this, I think we can be confident that even if fb had some 15-year-old tool in use on its fleet of 2GB-file filesystems, it would not be the one to insist on a kernel revert of 64-bit tmpfs inos. The picture looks clear now: while ChrisD does need to hold on to his config option and inode32/inode64 mount option patch, it is much better left out of the kernel until (very unlikely) proved necessary. Thanks, Hugh