===== DF-3042: hammer volume-header CRC never verified at mount =====
You may have to run 'hammer prune-everything' and 'hammer reblock'
quite often, even if using a nohistory mount.
sizeof(hdr)=1928 vol_crc@156 CRCSIZE1=156(+4) CRCSIZE2=1768
stored vol_crc          = 0000000000000000
computed CRC (before)   = e9dddf1be6882658 (MISMATCH)
computed CRC (after)    = e9dddf1b34f0db36 (differs from stored -> header invalid)
flipped vol_reserved[7] byte; vol_crc left stale
MOUNT SUCCEEDED with CRC-corrupted volume header <-- BUG