DragonFlyBSD

I started the build as
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nice n 9 make -j 8 buildworld
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@USR-SRC is mounted at /usr/scr, @USR-OBJ is mounted at /usr/obj.
The compilation stalled, I pressed reset and after reboot the system dumped immediately.
After that I was able to boot, but the PFSes were gone.

Each attempt to mount any of them led to the following errors:
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Sep 19 17:23:31 fly kernel: hammer2_mount
Sep 19 17:23:31 fly kernel: hammer2_mount: dev="/dev/serno/WD-WCC2EP295836.s1d" label="USR-OBJ" rdonly=0
Sep 19 17:23:31 fly kernel: hammer2: using volume header #3
Sep 19 17:23:31 fly kernel: alloc spmp 0xffffff8525bc0000 tid 000000000000c00b
Sep 19 17:23:31 fly kernel: chain 00000068a0f4480a.01 key=0000000000000000 meth=31 CHECK FAIL (flags=00144002, bref/data f84c9b21bc9ef301/1e55118462e960c9)
Sep 19 17:23:31 fly kernel: hammer2_mount: error Check Error reading super-root
Sep 19 17:23:31 fly kernel: hammer2_unmount hmp=0xffffff852613a000 mount_count=0
Sep 19 17:23:31 fly kernel: unmount hmp 0xffffff852613a000 remove spmp 0xffffff8525bc0000
Sep 19 17:23:31 fly kernel: unmount hmp 0xffffff852613a000 last ref to PMP=0xffffff8525bc0000
Sep 19 17:23:31 fly kernel: pfsfree: 0xffffff8525bc0000 lrucount=0
Sep 19 17:23:31 fly kernel: hammer2_unmount(A): devvp /dev/serno/WD-WCC2EP295836.s1d rbdirty 0 ronly=0
Sep 19 17:23:31 fly kernel: hammer2_unmount(B): devvp /dev/serno/WD-WCC2EP295836.s1d rbdirty 0
Sep 19 17:23:31 fly kernel: v-chain 0xffffff852613a4c0.255 0000000000000000/0 mir=000000000000c00b
Sep 19 17:23:31 fly kernel: [00002000] (?) refs=1
Sep 19 17:23:31 fly kernel: f-chain 0xffffff852613a640.254 0000000000000000/0 mir=000000000000c00a
Sep 19 17:23:31 fly kernel: [00000004] (?) refs=0
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