==== [1] create a valid 4 GB HAMMER image ====
0 bytes transferred in 0.000070 secs (0 bytes/sec)
WARNING: HAMMER filesystems less than 50GB are not recommended!
You may have to run 'hammer prune-everything' and 'hammer reblock'
quite often, even if using a nohistory mount.
==== [2] mount RW briefly so the btree root is allocated ====
rw mount populated and unmounted
==== [3] snapshot btree_root value before patch ====
00000000  00 00 00 21 00 00 00 80                           |...!....|
==== [4] patch vol0_btree_root low 14 bits -> 0x3FFC ====
vol0_btree_root: 0x8000000021000000 -> 0x8000000021003ffc
patched image; btree_root now:
00000000  fc 3f 00 21 00 00 00 80                           |.?.!....|
==== [5] clear dmesg tail marker, then attempt RO mount ====
mount: Invalid argument
mount_hammer rc=1
==== [6] try to trigger btree traversal ====
total 4
drwxr-xr-x  1 root  wheel  0 Jul 13 22:10 .
drwxr-xr-x  1 root  wheel  0 Jul 13 22:10 ..
ls rc=0
==== [7] any kernel messages from the path? ====
Mounting root from hammer2:vbd0s1d
hammer2_mount: root devstr="vbd0s1d"
hammer2_mount: device="vbd0s1d" label="ROOT" rdonly=1
hammer2_ondisk: "/dev/vbd0s1d" zone=2 id=0 offset=0x0000000000000000 size=0x000000063f000000
hammer2_mount: hmp=0xfffff8008fae0000 pmp=0xfffff80090280000
hammer2_mount: "vbd0s1d": no recovery needed
hammer2: enable read/write
HAMMER2: VOLDATA DUMP
HAMMER2: INITIATE SPANs
HAMMER(df0798) recovery check seqno=000fffff
HAMMER(df0798) recovery range 3000000000000000-3000000000000000
HAMMER(df0798) recovery nexto 3000000000000000 endseqno=00100000
HAMMER(df0798) mounted clean, no recovery needed
HAMMER(df0798) recovery check seqno=0010001e
HAMMER(df0798) recovery range 3000000000002a38-3000000000002a38
HAMMER(df0798) recovery nexto 3000000000002a38 endseqno=0010001f
HAMMER(df0798) mounted clean, no recovery needed
HAMMER: malformed vol0_btree_root 8000000021003ffc
==== [8] cleanup ====
DONE