I rebooted one of the failing machines to an earlier kernel, and ceph-fs works fine there. i.e. works great for this kernel; with no other changes:
# cat /proc/version Linux version 6.12.57+deb13-amd64 ([email protected]) (x86_64-linux-gnu-gcc-14 (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44) #1 SMP PREEMPT_DYNAMIC Debian 6.12.57-1 (2025-11-05)
