On Mon, 29 Jun 2020 at 17:08, Staffan Thomén <d...@shangtai.net> wrote: > > Chavdar Ivanov wrote: > >> # ccdconfig -c ccd0 0 /dev/zvol/dsk/internal1/photos@backup > > > > You are mapping a snapshot, it will be r/o. > > > > You have to promote it first. > > While it's true that the snapshot is r/o, surely it shouldn't crash the > system.
Sure, > > And is there a reason why ccd would require r/w? > > Staffan > Well, I got the same crash: uvm_fault(0xffff847d4c69ae58, 0x0, 1) -> e fatal page fault in supervisor mode trap type 6 code 0 rip 0xffffffff80d648cc cs 0x8 rflags 0x10246 cr2 0x18 ilevel 0 rsp 0xffff94819c763d80 curlwp 0xffff847d2ec79940 pid 10964.10964 lowest kstack 0xffff94819c7602c0 panic: trap cpu0: Begin traceback... vpanic() at netbsd:vpanic+0x152 snprintf() at netbsd:snprintf startlwp() at netbsd:startlwp alltraps() at netbsd:alltraps+0xc3 sysctl_dispatch() at netbsd:sysctl_dispatch+0xa5 sys___sysctl() at netbsd:sys___sysctl+0xc5 syscall() at netbsd:syscall+0x26e --- syscall (number 202) --- netbsd:syscall+0x26e: cpu0: End traceback... when I tried ccdconfig onto the snapshot; when I cloned the zvol (not promote, my mistake), it works: # zfs clone pail/nbsd1@testa pail/nbsd2 # ccdconfig -c ccd0 0 /dev/zvol/dsk/pail/nbsd2 # crash ccdconfig -g ccd0 0 0x0 4294967296 /dev/zvol/dsk/pail/nbsd2 I'd say the zvol snapshot is perhaps only relevant to ZFS internal operations; you have to have a real zvol to be able to access it with any external to ZFS tools, like istgt or ccdconfig. As far as I remember, even under Solaris you couldn't do much with a snapshot of a zvol, other than clone it or send it. But the panic should be examined, of course. -- ----
