DF-2717 storm: 150s, 3 readers, mode=0x9 (1=fchdir-swap 2=relchdir 4=dance 8=readers), A=/tmp/df2717/a B=/home/maxx/df2717/b
DF-2717 storm done in 150.0s
  fchdir swaps       : 156107562 (1040482/s)
  relative chdirs    : 0 (0/s)
  volatile dance cyc : 0 (0/s)
  reader opens       : 161845152 (1078724/s, enoent 161845152)
RUN_RC=0
guest status after: up   (NO PANIC)

[Dedicated sub-storm isolating the DF-2717 torn-two-word-load claim:
1.04M/s cross-mount fchdir swaps (tmpfs <-> hammer2 mount pointers)
against 1.08M/s relative-path reader lookups for 150 s.
~1.6e8 swap events x ~1.6e8 nlookup_init cache_copy reads.
Result: clean. The two-adjacent-loads window never landed.]