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* grub2-probe confused by double bind mount?
@ 2017-08-03  7:24 Chris Murphy
  2017-08-07  6:56 ` Chris Murphy
  0 siblings, 1 reply; 7+ messages in thread
From: Chris Murphy @ 2017-08-03  7:24 UTC (permalink / raw)
  To: The development of GNU GRUB

Running grub2-mkconfig complains with

grub2-probe: error: cannot find a device for / (is /dev mounted?).

/dev is mounted and looks valid. If I point grub2-probe to / I get the
same error, whereas if I point it to the /dev device mounted to it, it
exits normally.

I suspect grub2-probe is confused due to double bind mounting, but I
can't directly prove it.

The problem only happens when / is built first by mounting with '-o
subvol=root' (Btrfs subvolume) and also ostree. If I drop one of
those, the problem doesn't happen. But in combination, the problem
does happen.

On line 1 (in details below), the Btrfs subvol command is implemented
behind the scenes as a bind mount.

On line 14 is --rbind of /mnt/sysimage elsewhere, required for ostree assembly.


Details of mounting process, and output from grub2-probe:

pretty version
https://paste.fedoraproject.org/paste/YFWQW33yBHkLcyzIzL4XuQ

likely clobbered by the MUA version:

# mount -t btrfs -o subvol=root /dev/sda7 /mnt/sysimage
# mount -t ext4 -o defaults /dev/sda5 /mnt/sysimage/boot
# mount -t hfsplus -o defaults /dev/sda4 /mnt/sysimage/boot/efi
# mount -t bind -o bind,defaults /dev /mnt/sysimage/dev
# mount -t devpts -o gid=5,mode=620 devpts /mnt/sysimage/dev/pts
# mount -t tmpfs -o defaults tmpfs /mnt/sysimage/dev/shm
# mount -t proc -o defaults proc /mnt/sysimage/proc
# mount -t bind -o bind,defaults /run /mnt/sysimage/run
# mount -t sysfs -o defaults sysfs /mnt/sysimage/sys
# mount -t efivarfs -o defaults efivarfs /mnt/sysimage/sys/firmware/efi/efivars
# mount -t selinuxfs -o defaults selinuxfs /mnt/sysimage/sys/fs/selinux
# mount --bind /mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0/usr
/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0/usr
# mount --bind -o remount,ro
/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0/usr
/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0/usr
# mount --rbind /mnt/sysimage
/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0/sysroot
# mount --rbind /mnt/sysimage/boot
/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0/boot
# mount --rbind /mnt/sysimage/ostree/deploy/fedora-workstation/var
/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0/var
# mount --rbind /mnt/sysimage/dev
/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0/dev
# mount --rbind /mnt/sysimage/proc
/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0/proc
# mount --rbind /mnt/sysimage/run
/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0/run
# mount --rbind /mnt/sysimage/sys
/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0/sys
# systemd-tmpfiles --create --boot
--root=/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0
--prefix=/var/home
# systemd-tmpfiles --create --boot
--root=/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0
--prefix=/var/roothome
# systemd-tmpfiles --create --boot
--root=/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0
--prefix=/var/lib/rpm
# systemd-tmpfiles --create --boot
--root=/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0
--prefix=/var/opt
# systemd-tmpfiles --create --boot
--root=/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0
--prefix=/var/srv
# systemd-tmpfiles --create --boot
--root=/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0
--prefix=/var/usrlocal
# systemd-tmpfiles --create --boot
--root=/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0
--prefix=/var/mnt
# systemd-tmpfiles --create --boot
--root=/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0
--prefix=/var/media
# systemd-tmpfiles --create --boot
--root=/mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0
--prefix=/var/spool/mail
# chroot /mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0/
# ls -l /dev
total 0
crw-------.  1 root  root     10, 235 Aug  3  2017 autofs
drwxr-xr-x.  2 root  root         440 Aug  2 21:23 block
drwxr-xr-x.  2 root  root         120 Aug  2 21:23 bsg
crw-rw----.  1 root  disk     10, 234 Aug  3  2017 btrfs-control
drwxr-xr-x.  3 root  root          60 Aug  2 21:22 bus
lrwxrwxrwx.  1 root  root           3 Aug  3  2017 cdrom -> sr0
drwxr-xr-x.  2 root  root        4720 Aug  2 21:23 char
crw-------.  1 root  root      5,   1 Aug  2 21:23 console
lrwxrwxrwx.  1 root  root          11 Aug  2 21:22 core -> /proc/kcore
drwxr-xr-x. 10 root  root         220 Aug  2 21:22 cpu
crw-------.  1 root  root     10,  62 Aug  3  2017 cpu_dma_latency
crw-------.  1 root  root     10, 203 Aug  2 21:22 cuse
drwxr-xr-x.  8 root  root         160 Aug  2 21:22 disk
brw-rw----.  1 root  disk    253,   0 Aug  3  2017 dm-0
brw-rw----.  1 root  disk    253,   1 Aug  3  2017 dm-1
drwxr-xr-x.  3 root  root         140 Aug  3  2017 dri
crw-------.  1 root  root    240,   0 Aug  3  2017 drm_dp_aux0
crw-------.  1 root  root    240,   1 Aug  3  2017 drm_dp_aux1
crw-------.  1 root  root    240,   2 Aug  3  2017 drm_dp_aux2
crw-------.  1 root  root    240,   3 Aug  3  2017 drm_dp_aux3
crw-rw----.  1 root  video    29,   0 Aug  3  2017 fb0
crw-rw----.  1 root  video    29,   1 Aug  3  2017 fb1
lrwxrwxrwx.  1 root  root          13 Aug  2 21:22 fd -> /proc/self/fd
crw-rw-rw-.  1 root  root      1,   7 Aug  3  2017 full
crw-rw-rw-.  1 root  root     10, 229 Aug  3  2017 fuse
crw-------.  1 root  root    243,   0 Aug  3  2017 fw0
crw-------.  1 root  root    254,   0 Aug  3  2017 gpiochip0
crw-------.  1 root  root    246,   1 Aug  3  2017 hidraw1
crw-------.  1 root  root    246,   2 Aug  3  2017 hidraw2
crw-------.  1 root  root    246,   3 Aug  3  2017 hidraw3
crw-------.  1 root  root     10, 228 Aug  3  2017 hpet
drwxr-xr-x.  2 root  root          40 Aug  3  2017 hugepages
crw-------.  1 root  root     10, 183 Aug  3  2017 hwrng
crw-------.  1 root  root    241,   0 Aug  3  2017 iio:device0
lrwxrwxrwx.  1 root  root          25 Aug  3  2017 initctl ->
/run/systemd/initctl/fifo
drwxr-xr-x.  4 root  root         440 Aug  3  2017 input
crw-------.  1 root  root    238,   0 Aug  3  2017 kfd
crw-r--r--.  1 root  root      1,  11 Aug  3  2017 kmsg
crw-rw-rw-+  1 root  kvm      10, 232 Aug  3  2017 kvm
lrwxrwxrwx.  1 root  root          28 Aug  2 21:22 log ->
/run/systemd/journal/dev-log
brw-rw----.  1 root  disk      7,   0 Aug  3  2017 loop0
brw-rw----.  1 root  disk      7,   1 Aug  3  2017 loop1
brw-rw----.  1 root  disk      7,   2 Aug  3  2017 loop2
crw-rw----.  1 root  disk     10, 237 Aug  3  2017 loop-control
crw-rw----.  1 root  lp        6,   0 Aug  3  2017 lp0
crw-rw----.  1 root  lp        6,   1 Aug  3  2017 lp1
crw-rw----.  1 root  lp        6,   2 Aug  3  2017 lp2
crw-rw----.  1 root  lp        6,   3 Aug  3  2017 lp3
drwxr-xr-x.  2 root  root         100 Aug  2 21:22 mapper
crw-------.  1 root  root     10, 227 Aug  3  2017 mcelog
crw-rw----.  1 root  video   239,   0 Aug  3  2017 media0
crw-------.  1 root  root    242,   0 Aug  3  2017 mei0
crw-r-----.  1 root  kmem      1,   1 Aug  3  2017 mem
crw-------.  1 root  root     10,  59 Aug  3  2017 memory_bandwidth
drwxr-xr-x.  2 root  root          40 Aug  3  2017 mqueue
drwxr-xr-x.  2 root  root          60 Aug  2 21:22 net
crw-------.  1 root  root     10,  61 Aug  3  2017 network_latency
crw-------.  1 root  root     10,  60 Aug  3  2017 network_throughput
crw-rw-rw-.  1 root  root      1,   3 Aug  3  2017 null
crw-------.  1 root  root     10, 144 Aug  3  2017 nvram
crw-r-----.  1 root  kmem      1,   4 Aug  3  2017 port
crw-------.  1 root  root    108,   0 Aug  3  2017 ppp
crw-rw-rw-.  1 root  tty       5,   2 Aug  3 00:27 ptmx
drwxr-xr-x.  2 root  root           0 Aug  3 00:03 pts
crw-rw-rw-.  1 root  root      1,   8 Aug  3  2017 random
drwxr-xr-x.  2 root  root          60 Aug  2 21:22 raw
crw-rw-r--+  1 root  root     10,  58 Aug  3  2017 rfkill
lrwxrwxrwx.  1 root  root           4 Aug  3  2017 rtc -> rtc0
crw-------.  1 root  root    250,   0 Aug  3  2017 rtc0
brw-rw----.  1 root  disk      8,   0 Aug  3  2017 sda
brw-rw----.  1 root  disk      8,   1 Aug  3  2017 sda1
brw-rw----.  1 root  disk      8,   2 Aug  3  2017 sda2
brw-rw----.  1 root  disk      8,   3 Aug  3  2017 sda3
brw-rw----.  1 root  disk      8,   4 Aug  3  2017 sda4
brw-rw----.  1 root  disk      8,   5 Aug  3  2017 sda5
brw-rw----.  1 root  disk      8,   6 Aug  3  2017 sda6
brw-rw----.  1 root  disk      8,   7 Aug  3  2017 sda7
brw-rw----.  1 root  disk      8,  16 Aug  3  2017 sdb
brw-rw----.  1 root  disk      8,  17 Aug  3  2017 sdb1
brw-rw----.  1 root  disk      8,  18 Aug  3  2017 sdb2
brw-rw----.  1 root  disk      8,  19 Aug  3  2017 sdb3
brw-rw----.  1 root  disk      8,  32 Aug  2 21:23 sdc
brw-rw----.  1 root  disk      8,  33 Aug  2 21:23 sdc1
crw-rw----.  1 root  disk     21,   0 Aug  3  2017 sg0
crw-rw----+  1 root  cdrom    21,   1 Aug  3  2017 sg1
crw-rw----.  1 root  disk     21,   2 Aug  3  2017 sg2
crw-rw----.  1 root  disk     21,   3 Aug  2 21:23 sg3
drwxrwxrwt.  2 root  root          40 Aug  3 00:03 shm
crw-------.  1 root  root     10, 231 Aug  3  2017 snapshot
drwxr-xr-x.  3 root  root         280 Aug  3  2017 snd
brw-rw----+  1 root  cdrom    11,   0 Aug  3  2017 sr0
lrwxrwxrwx.  1 root  root          15 Aug  2 21:22 stderr -> /proc/self/fd/2
lrwxrwxrwx.  1 root  root          15 Aug  2 21:22 stdin -> /proc/self/fd/0
lrwxrwxrwx.  1 root  root          15 Aug  2 21:22 stdout -> /proc/self/fd/1
crw-rw-rw-.  1 root  tty       5,   0 Aug  3  2017 tty
crw--w----.  1 root  tty       4,   0 Aug  3  2017 tty0
crw--w----.  1 gdm   tty       4,   1 Aug  3  2017 tty1
crw--w----.  1 root  tty       4,  10 Aug  3  2017 tty10
crw--w----.  1 root  tty       4,  11 Aug  3  2017 tty11
crw--w----.  1 root  tty       4,  12 Aug  3  2017 tty12
crw--w----.  1 root  tty       4,  13 Aug  3  2017 tty13
crw--w----.  1 root  tty       4,  14 Aug  3  2017 tty14
crw--w----.  1 root  tty       4,  15 Aug  3  2017 tty15
crw--w----.  1 root  tty       4,  16 Aug  3  2017 tty16
crw--w----.  1 root  tty       4,  17 Aug  3  2017 tty17
crw--w----.  1 root  tty       4,  18 Aug  3  2017 tty18
crw--w----.  1 root  tty       4,  19 Aug  3  2017 tty19
crw--w----.  1 chris tty       4,   2 Aug  3  2017 tty2
crw--w----.  1 root  tty       4,  20 Aug  3  2017 tty20
crw--w----.  1 root  tty       4,  21 Aug  3  2017 tty21
crw--w----.  1 root  tty       4,  22 Aug  3  2017 tty22
crw--w----.  1 root  tty       4,  23 Aug  3  2017 tty23
crw--w----.  1 root  tty       4,  24 Aug  3  2017 tty24
crw--w----.  1 root  tty       4,  25 Aug  3  2017 tty25
crw--w----.  1 root  tty       4,  26 Aug  3  2017 tty26
crw--w----.  1 root  tty       4,  27 Aug  3  2017 tty27
crw--w----.  1 root  tty       4,  28 Aug  3  2017 tty28
crw--w----.  1 root  tty       4,  29 Aug  3  2017 tty29
crw--w----.  1 root  tty       4,   3 Aug  3  2017 tty3
crw--w----.  1 root  tty       4,  30 Aug  3  2017 tty30
crw--w----.  1 root  tty       4,  31 Aug  3  2017 tty31
crw--w----.  1 root  tty       4,  32 Aug  3  2017 tty32
crw--w----.  1 root  tty       4,  33 Aug  3  2017 tty33
crw--w----.  1 root  tty       4,  34 Aug  3  2017 tty34
crw--w----.  1 root  tty       4,  35 Aug  3  2017 tty35
crw--w----.  1 root  tty       4,  36 Aug  3  2017 tty36
crw--w----.  1 root  tty       4,  37 Aug  3  2017 tty37
crw--w----.  1 root  tty       4,  38 Aug  3  2017 tty38
crw--w----.  1 root  tty       4,  39 Aug  3  2017 tty39
crw--w----.  1 root  tty       4,   4 Aug  3  2017 tty4
crw--w----.  1 root  tty       4,  40 Aug  3  2017 tty40
crw--w----.  1 root  tty       4,  41 Aug  3  2017 tty41
crw--w----.  1 root  tty       4,  42 Aug  3  2017 tty42
crw--w----.  1 root  tty       4,  43 Aug  3  2017 tty43
crw--w----.  1 root  tty       4,  44 Aug  3  2017 tty44
crw--w----.  1 root  tty       4,  45 Aug  3  2017 tty45
crw--w----.  1 root  tty       4,  46 Aug  3  2017 tty46
crw--w----.  1 root  tty       4,  47 Aug  3  2017 tty47
crw--w----.  1 root  tty       4,  48 Aug  3  2017 tty48
crw--w----.  1 root  tty       4,  49 Aug  3  2017 tty49
crw--w----.  1 root  tty       4,   5 Aug  3  2017 tty5
crw--w----.  1 root  tty       4,  50 Aug  3  2017 tty50
crw--w----.  1 root  tty       4,  51 Aug  3  2017 tty51
crw--w----.  1 root  tty       4,  52 Aug  3  2017 tty52
crw--w----.  1 root  tty       4,  53 Aug  3  2017 tty53
crw--w----.  1 root  tty       4,  54 Aug  3  2017 tty54
crw--w----.  1 root  tty       4,  55 Aug  3  2017 tty55
crw--w----.  1 root  tty       4,  56 Aug  3  2017 tty56
crw--w----.  1 root  tty       4,  57 Aug  3  2017 tty57
crw--w----.  1 root  tty       4,  58 Aug  3  2017 tty58
crw--w----.  1 root  tty       4,  59 Aug  3  2017 tty59
crw--w----.  1 root  tty       4,   6 Aug  3  2017 tty6
crw--w----.  1 root  tty       4,  60 Aug  3  2017 tty60
crw--w----.  1 root  tty       4,  61 Aug  3  2017 tty61
crw--w----.  1 root  tty       4,  62 Aug  3  2017 tty62
crw--w----.  1 root  tty       4,  63 Aug  3  2017 tty63
crw--w----.  1 root  tty       4,   7 Aug  3  2017 tty7
crw--w----.  1 root  tty       4,   8 Aug  3  2017 tty8
crw--w----.  1 root  tty       4,   9 Aug  3  2017 tty9
crw-rw----.  1 root  dialout   4,  64 Aug  3  2017 ttyS0
crw-rw----.  1 root  dialout   4,  65 Aug  3  2017 ttyS1
crw-rw----.  1 root  dialout   4,  74 Aug  3  2017 ttyS10
crw-rw----.  1 root  dialout   4,  75 Aug  3  2017 ttyS11
crw-rw----.  1 root  dialout   4,  76 Aug  3  2017 ttyS12
crw-rw----.  1 root  dialout   4,  77 Aug  3  2017 ttyS13
crw-rw----.  1 root  dialout   4,  78 Aug  3  2017 ttyS14
crw-rw----.  1 root  dialout   4,  79 Aug  3  2017 ttyS15
crw-rw----.  1 root  dialout   4,  80 Aug  3  2017 ttyS16
crw-rw----.  1 root  dialout   4,  81 Aug  3  2017 ttyS17
crw-rw----.  1 root  dialout   4,  82 Aug  3  2017 ttyS18
crw-rw----.  1 root  dialout   4,  83 Aug  3  2017 ttyS19
crw-rw----.  1 root  dialout   4,  66 Aug  3  2017 ttyS2
crw-rw----.  1 root  dialout   4,  84 Aug  3  2017 ttyS20
crw-rw----.  1 root  dialout   4,  85 Aug  3  2017 ttyS21
crw-rw----.  1 root  dialout   4,  86 Aug  3  2017 ttyS22
crw-rw----.  1 root  dialout   4,  87 Aug  3  2017 ttyS23
crw-rw----.  1 root  dialout   4,  88 Aug  3  2017 ttyS24
crw-rw----.  1 root  dialout   4,  89 Aug  3  2017 ttyS25
crw-rw----.  1 root  dialout   4,  90 Aug  3  2017 ttyS26
crw-rw----.  1 root  dialout   4,  91 Aug  3  2017 ttyS27
crw-rw----.  1 root  dialout   4,  92 Aug  3  2017 ttyS28
crw-rw----.  1 root  dialout   4,  93 Aug  3  2017 ttyS29
crw-rw----.  1 root  dialout   4,  67 Aug  3  2017 ttyS3
crw-rw----.  1 root  dialout   4,  94 Aug  3  2017 ttyS30
crw-rw----.  1 root  dialout   4,  95 Aug  3  2017 ttyS31
crw-rw----.  1 root  dialout   4,  68 Aug  3  2017 ttyS4
crw-rw----.  1 root  dialout   4,  69 Aug  3  2017 ttyS5
crw-rw----.  1 root  dialout   4,  70 Aug  3  2017 ttyS6
crw-rw----.  1 root  dialout   4,  71 Aug  3  2017 ttyS7
crw-rw----.  1 root  dialout   4,  72 Aug  3  2017 ttyS8
crw-rw----.  1 root  dialout   4,  73 Aug  3  2017 ttyS9
crw-------.  1 root  root     10, 239 Aug  2 21:22 uhid
crw-------.  1 root  root     10, 223 Aug  3  2017 uinput
crw-rw-rw-.  1 root  root      1,   9 Aug  3  2017 urandom
drwxr-xr-x.  2 root  root          60 Aug  2 21:22 usb
crw-------.  1 root  root    247,   0 Aug  3  2017 usbmon0
crw-------.  1 root  root    247,   1 Aug  3  2017 usbmon1
crw-------.  1 root  root    247,   2 Aug  3  2017 usbmon2
crw-------.  1 root  root    247,   3 Aug  3  2017 usbmon3
crw-------.  1 root  root    247,   4 Aug  3  2017 usbmon4
drwxr-xr-x.  4 root  root          80 Aug  3  2017 v4l
crw-rw----.  1 root  tty       7,   0 Aug  3  2017 vcs
crw-rw----.  1 root  tty       7,   1 Aug  3  2017 vcs1
crw-rw----.  1 root  tty       7,   2 Aug  3  2017 vcs2
crw-rw----.  1 root  tty       7,   3 Aug  3  2017 vcs3
crw-rw----.  1 root  tty       7,   4 Aug  3  2017 vcs4
crw-rw----.  1 root  tty       7,   5 Aug  3  2017 vcs5
crw-rw----.  1 root  tty       7,   6 Aug  3  2017 vcs6
crw-rw----.  1 root  tty       7, 128 Aug  3  2017 vcsa
crw-rw----.  1 root  tty       7, 129 Aug  3  2017 vcsa1
crw-rw----.  1 root  tty       7, 130 Aug  3  2017 vcsa2
crw-rw----.  1 root  tty       7, 131 Aug  3  2017 vcsa3
crw-rw----.  1 root  tty       7, 132 Aug  3  2017 vcsa4
crw-rw----.  1 root  tty       7, 133 Aug  3  2017 vcsa5
crw-rw----.  1 root  tty       7, 134 Aug  3  2017 vcsa6
drwxr-xr-x.  2 root  root          60 Aug  3  2017 vfio
crw-------.  1 root  root     10,  63 Aug  3  2017 vga_arbiter
crw-------.  1 root  root     10, 137 Aug  3  2017 vhci
crw-------.  1 root  root     10, 238 Aug  3  2017 vhost-net
crw-------.  1 root  root     10, 241 Aug  3  2017 vhost-vsock
crw-rw----+  1 root  video    81,   0 Aug  3  2017 video0
crw-rw-rw-.  1 root  root      1,   5 Aug  3  2017 zero

# grub2-probe /
grub2-probe: error: cannot find a device for / (is /dev mounted?).
# grub2-probe -v /
grub2-probe: info: cannot open ‘/boot/grub2/device.map’: No such file
or directory.
grub2-probe: info: changing current directory to /dev.
grub2-probe: info: changing current directory to v4l.
grub2-probe: info: changing current directory to by-path.
grub2-probe: info: changing current directory to by-id.
grub2-probe: info: changing current directory to dri.
grub2-probe: info: changing current directory to by-path.
grub2-probe: info: changing current directory to snd.
grub2-probe: info: changing current directory to by-path.
grub2-probe: info: changing current directory to vfio.
grub2-probe: info: changing current directory to mqueue.
grub2-probe: info: changing current directory to hugepages.
grub2-probe: info: changing current directory to disk.
grub2-probe: info: changing current directory to by-uuid.
grub2-probe: info: changing current directory to by-partlabel.
grub2-probe: info: changing current directory to by-label.
grub2-probe: info: changing current directory to by-partuuid.
grub2-probe: info: changing current directory to by-path.
grub2-probe: info: changing current directory to by-id.
grub2-probe: info: changing current directory to block.
grub2-probe: info: changing current directory to usb.
grub2-probe: info: changing current directory to char.
grub2-probe: info: changing current directory to net.
grub2-probe: info: changing current directory to pts.
grub2-probe: info: changing current directory to shm.
grub2-probe: info: changing current directory to bsg.
grub2-probe: info: changing current directory to mapper.
grub2-probe: info: changing current directory to input.
grub2-probe: info: changing current directory to by-path.
grub2-probe: info: changing current directory to by-id.
grub2-probe: info: changing current directory to bus.
grub2-probe: info: changing current directory to usb.
grub2-probe: info: changing current directory to 004.
grub2-probe: info: changing current directory to 003.
grub2-probe: info: changing current directory to 002.
grub2-probe: info: changing current directory to 001.
grub2-probe: info: changing current directory to raw.
grub2-probe: info: changing current directory to cpu.
grub2-probe: info: changing current directory to 7.
grub2-probe: info: changing current directory to 6.
grub2-probe: info: changing current directory to 5.
grub2-probe: info: changing current directory to 4.
grub2-probe: info: changing current directory to 3.
grub2-probe: info: changing current directory to 2.
grub2-probe: info: changing current directory to 1.
grub2-probe: info: changing current directory to 0.
grub2-probe: error: cannot find a device for / (is /dev mounted?).
#

# grub2-probe -v --device /dev/sda7
grub2-probe: info: cannot open ‘/boot/grub2/device.map’: No such file
or directory.
grub2-probe: info: /dev/sda7 is not present.
grub2-probe: info: Looking for /dev/sda7.
grub2-probe: info: /dev/sda is a parent of /dev/sda7.
grub2-probe: info: /dev/sda7 starts from 264892416.
grub2-probe: info: opening the device hostdisk//dev/sda.
grub2-probe: info: drive = 0.
grub2-probe: info: the size of hostdisk//dev/sda is 488397168.
grub2-probe: info: drive = 0.
grub2-probe: info: the size of hostdisk//dev/sda is 488397168.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Partition 0 starts from 40.
grub2-probe: info: Partition 1 starts from 409640.
grub2-probe: info: Partition 2 starts from 244750664.
grub2-probe: info: Partition 3 starts from 246022144.
grub2-probe: info: Partition 4 starts from 246431744.
grub2-probe: info: Partition 5 starts from 248528896.
grub2-probe: info: Partition 6 starts from 264892416.
grub2-probe: info: /dev/sda7 is present.
grub2-probe: info: Looking for /dev/sda7.
grub2-probe: info: /dev/sda is a parent of /dev/sda7.
grub2-probe: info: /dev/sda7 starts from 264892416.
grub2-probe: info: opening the device hostdisk//dev/sda.
grub2-probe: info: drive = 0.
grub2-probe: info: the size of hostdisk//dev/sda is 488397168.
grub2-probe: info: drive = 0.
grub2-probe: info: the size of hostdisk//dev/sda is 488397168.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Partition 0 starts from 40.
grub2-probe: info: Partition 1 starts from 409640.
grub2-probe: info: Partition 2 starts from 244750664.
grub2-probe: info: Partition 3 starts from 246022144.
grub2-probe: info: Partition 4 starts from 246431744.
grub2-probe: info: Partition 5 starts from 248528896.
grub2-probe: info: Partition 6 starts from 264892416.
grub2-probe: info: /dev/sda7 is present.
grub2-probe: info: Looking for /dev/sda7.
grub2-probe: info: /dev/sda is a parent of /dev/sda7.
grub2-probe: info: /dev/sda7 starts from 264892416.
grub2-probe: info: opening the device hostdisk//dev/sda.
grub2-probe: info: drive = 0.
grub2-probe: info: the size of hostdisk//dev/sda is 488397168.
grub2-probe: info: drive = 0.
grub2-probe: info: the size of hostdisk//dev/sda is 488397168.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Scanning for DISKFILTER devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid1x devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09 devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for mdraid09_be devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for dmraid_nv devices on disk hostdisk//dev/sda.
grub2-probe: info: Scanning for ldm devices on disk hostdisk//dev/sda.
grub2-probe: info: scanning hostdisk//dev/sda for LDM.
grub2-probe: info: no LDM signature found.
grub2-probe: info: Scanning for lvm devices on disk hostdisk//dev/sda.
grub2-probe: info: no LVM signature found.
grub2-probe: info: Partition 0 starts from 40.
grub2-probe: info: Partition 1 starts from 409640.
grub2-probe: info: Partition 2 starts from 244750664.
grub2-probe: info: Partition 3 starts from 246022144.
grub2-probe: info: Partition 4 starts from 246431744.
grub2-probe: info: Partition 5 starts from 248528896.
grub2-probe: info: Partition 6 starts from 264892416.
grub2-probe: info: opening hostdisk//dev/sda,gpt7.
grub2-probe: info: drive = 0.
grub2-probe: info: the size of hostdisk//dev/sda is 488397168.
btrfs
#


Also curious, this sequence while in the chroot (up until exiting)

# grub2-probe ostree
btrfs
# grub2-probe sysroot
btrfs
]# grub2-probe usr
btrfs
# grub2-probe var
btrfs
# grub2-probe etc
grub2-probe: error: cannot find a device for etc (is /dev mounted?).
# exit
# grub2-probe /mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0/
btrfs
# chroot /mnt/sysimage/ostree/deploy/fedora-workstation/deploy/e52f5de4c5d3f52211ab216d5bf5331b81c929e967f9cbfcba3ad85e45f8fd37.0/
# grub2-probe /
grub2-probe: error: cannot find a device for / (is /dev mounted?).





-- 
Chris Murphy


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: grub2-probe confused by double bind mount?
  2017-08-03  7:24 grub2-probe confused by double bind mount? Chris Murphy
@ 2017-08-07  6:56 ` Chris Murphy
  2017-08-07  7:15   ` Xen
  2017-08-07 15:09   ` Vladimir 'phcoder' Serbinenko
  0 siblings, 2 replies; 7+ messages in thread
From: Chris Murphy @ 2017-08-07  6:56 UTC (permalink / raw)
  To: Chris Murphy; +Cc: The development of GNU GRUB

It's not the double bind mount. I've removed it by eliminating the -o
subvol option and adjusted paths accordingly during assembly. But
grub2-probe still fails inside the chroot, even though it works on the
path I'm chrooting.

mount assembly
https://pastebin.com/LMSPeeiP

strace grub2-probe inside chroot (fails)
https://pastebin.com/S1mA8RTh

strace grub2-probe outside chroot (succeeds)
https://pastebin.com/VkfZnsKu


In the outside chroot (working) case, line 233 it figures out it's
Btrfs with Btrfs specific ioctls. Where the failing case never does
even after digging around in /dev/ which it does find and yet
complaint that it's not mounted. So the error message itself seems
bogus and only a symptom of confusion and not what or why the actual
problem is happening.

The non-working case looks like it starts failing after line 213,
openat /proc/self/mountinfo as if whatever it finds there is not at
all helpful.

inside
< 693 225 0:6 / /dev rw,nosuid shared:22 - devtmpfs devtmpfs
rw,seclabel,size=3999060k,nr_inodes=999765,mode=755

outside
> 21 71 0:6 / /dev rw,nosuid shared:22 - devtmpfs devtmpfs rw,seclabel,size=3999060k,nr_inodes=999765,mode=755


Chris Murphy


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: grub2-probe confused by double bind mount?
  2017-08-07  6:56 ` Chris Murphy
@ 2017-08-07  7:15   ` Xen
  2017-08-07 15:09   ` Vladimir 'phcoder' Serbinenko
  1 sibling, 0 replies; 7+ messages in thread
From: Xen @ 2017-08-07  7:15 UTC (permalink / raw)
  To: grub-devel

Chris Murphy schreef op 07-08-2017 8:56:

> The non-working case looks like it starts failing after line 213,
> openat /proc/self/mountinfo as if whatever it finds there is not at
> all helpful.

The only similar thing I ever experienced is when my system inside a 
chroot actually had a line filtering out a certain volume group or 
physical volume for LVM, thereby mysteriously causing a command to fail 
inside the chroot but not outside of it ;-).

Probably not helpful, but I thought I'd mention.


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: grub2-probe confused by double bind mount?
  2017-08-07  6:56 ` Chris Murphy
  2017-08-07  7:15   ` Xen
@ 2017-08-07 15:09   ` Vladimir 'phcoder' Serbinenko
  2017-08-08  4:35     ` Chris Murphy
  1 sibling, 1 reply; 7+ messages in thread
From: Vladimir 'phcoder' Serbinenko @ 2017-08-07 15:09 UTC (permalink / raw)
  To: The development of GNU GRUB, Chris Murphy

[-- Attachment #1: Type: text/plain, Size: 1585 bytes --]

Upstream doesn't use grub2 prefix. Please try with latest upstream and make
sure it's compiled with libdevmapper

On Mon, Aug 7, 2017, 08:57 Chris Murphy <lists@colorremedies.com> wrote:

> It's not the double bind mount. I've removed it by eliminating the -o
> subvol option and adjusted paths accordingly during assembly. But
> grub2-probe still fails inside the chroot, even though it works on the
> path I'm chrooting.
>
> mount assembly
> https://pastebin.com/LMSPeeiP
>
> strace grub2-probe inside chroot (fails)
> https://pastebin.com/S1mA8RTh
>
> strace grub2-probe outside chroot (succeeds)
> https://pastebin.com/VkfZnsKu
>
>
> In the outside chroot (working) case, line 233 it figures out it's
> Btrfs with Btrfs specific ioctls. Where the failing case never does
> even after digging around in /dev/ which it does find and yet
> complaint that it's not mounted. So the error message itself seems
> bogus and only a symptom of confusion and not what or why the actual
> problem is happening.
>
> The non-working case looks like it starts failing after line 213,
> openat /proc/self/mountinfo as if whatever it finds there is not at
> all helpful.
>
> inside
> < 693 225 0:6 / /dev rw,nosuid shared:22 - devtmpfs devtmpfs
> rw,seclabel,size=3999060k,nr_inodes=999765,mode=755
>
> outside
> > 21 71 0:6 / /dev rw,nosuid shared:22 - devtmpfs devtmpfs
> rw,seclabel,size=3999060k,nr_inodes=999765,mode=755
>
>
> Chris Murphy
>
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> https://lists.gnu.org/mailman/listinfo/grub-devel
>

[-- Attachment #2: Type: text/html, Size: 2358 bytes --]

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: grub2-probe confused by double bind mount?
  2017-08-07 15:09   ` Vladimir 'phcoder' Serbinenko
@ 2017-08-08  4:35     ` Chris Murphy
  2017-08-08  8:04       ` Vladimir 'phcoder' Serbinenko
  0 siblings, 1 reply; 7+ messages in thread
From: Chris Murphy @ 2017-08-08  4:35 UTC (permalink / raw)
  To: Vladimir 'phcoder' Serbinenko
  Cc: The development of GNU GRUB, Chris Murphy

On Mon, Aug 7, 2017 at 9:09 AM, Vladimir 'phcoder' Serbinenko
<phcoder@gmail.com> wrote:
> Upstream doesn't use grub2 prefix. Please try with latest upstream and make
> sure it's compiled with libdevmapper


Same result with current git as of today.

[chris@f26wnuc grub]$ ./configure --build=x86_64 --host=x86_64
--with-platform=efi


GRUB2 will be compiled with following components:
Platform: x86_64-efi
With devmapper support: Yes

And in the chroot:

[root@localhost /]# /usr/local/sbin/grub-probe -V
/usr/local/sbin/grub-probe (GRUB) 2.03
[root@localhost /]# /usr/local/sbin/grub-probe -v /
/usr/local/sbin/grub-probe: info: cannot open `/boot/grub/device.map':
No such file or directory.
/usr/local/sbin/grub-probe: info: changing current directory to /dev.
/usr/local/sbin/grub-probe: info: changing current directory to v4l.
/usr/local/sbin/grub-probe: info: changing current directory to by-path.
/usr/local/sbin/grub-probe: info: changing current directory to by-id.
/usr/local/sbin/grub-probe: info: changing current directory to dri.
/usr/local/sbin/grub-probe: info: changing current directory to by-path.
/usr/local/sbin/grub-probe: info: changing current directory to snd.
/usr/local/sbin/grub-probe: info: changing current directory to by-path.
/usr/local/sbin/grub-probe: info: changing current directory to vfio.
/usr/local/sbin/grub-probe: info: changing current directory to mqueue.
/usr/local/sbin/grub-probe: info: changing current directory to hugepages.
/usr/local/sbin/grub-probe: info: changing current directory to disk.
/usr/local/sbin/grub-probe: info: changing current directory to by-uuid.
/usr/local/sbin/grub-probe: info: changing current directory to by-partuuid.
/usr/local/sbin/grub-probe: info: changing current directory to by-partlabel.
/usr/local/sbin/grub-probe: info: changing current directory to by-label.
/usr/local/sbin/grub-probe: info: changing current directory to by-path.
/usr/local/sbin/grub-probe: info: changing current directory to by-id.
/usr/local/sbin/grub-probe: info: changing current directory to block.
/usr/local/sbin/grub-probe: info: changing current directory to usb.
/usr/local/sbin/grub-probe: info: changing current directory to char.
/usr/local/sbin/grub-probe: info: changing current directory to net.
/usr/local/sbin/grub-probe: info: changing current directory to pts.
/usr/local/sbin/grub-probe: info: changing current directory to shm.
/usr/local/sbin/grub-probe: info: changing current directory to bsg.
/usr/local/sbin/grub-probe: info: changing current directory to mapper.
/usr/local/sbin/grub-probe: info: changing current directory to input.
/usr/local/sbin/grub-probe: info: changing current directory to by-path.
/usr/local/sbin/grub-probe: info: changing current directory to by-id.
/usr/local/sbin/grub-probe: info: changing current directory to bus.
/usr/local/sbin/grub-probe: info: changing current directory to usb.
/usr/local/sbin/grub-probe: info: changing current directory to 004.
/usr/local/sbin/grub-probe: info: changing current directory to 003.
/usr/local/sbin/grub-probe: info: changing current directory to 002.
/usr/local/sbin/grub-probe: info: changing current directory to 001.
/usr/local/sbin/grub-probe: info: changing current directory to raw.
/usr/local/sbin/grub-probe: info: changing current directory to cpu.
/usr/local/sbin/grub-probe: info: changing current directory to 7.
/usr/local/sbin/grub-probe: info: changing current directory to 6.
/usr/local/sbin/grub-probe: info: changing current directory to 5.
/usr/local/sbin/grub-probe: info: changing current directory to 4.
/usr/local/sbin/grub-probe: info: changing current directory to 3.
/usr/local/sbin/grub-probe: info: changing current directory to 2.
/usr/local/sbin/grub-probe: info: changing current directory to 1.
/usr/local/sbin/grub-probe: info: changing current directory to 0.
/usr/local/sbin/grub-probe: error: cannot find a device for / (is /dev
mounted?).
[root@localhost /]#






-- 
Chris Murphy


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: grub2-probe confused by double bind mount?
  2017-08-08  4:35     ` Chris Murphy
@ 2017-08-08  8:04       ` Vladimir 'phcoder' Serbinenko
  2017-08-08 23:29         ` Chris Murphy
  0 siblings, 1 reply; 7+ messages in thread
From: Vladimir 'phcoder' Serbinenko @ 2017-08-08  8:04 UTC (permalink / raw)
  To: Chris Murphy; +Cc: The development of GNU GRUB

[-- Attachment #1: Type: text/plain, Size: 4277 bytes --]

Did you mount /proc ? What is the contents of /proc/self/mountinfo ?

On Tue, Aug 8, 2017, 06:35 Chris Murphy <lists@colorremedies.com> wrote:

> On Mon, Aug 7, 2017 at 9:09 AM, Vladimir 'phcoder' Serbinenko
> <phcoder@gmail.com> wrote:
> > Upstream doesn't use grub2 prefix. Please try with latest upstream and
> make
> > sure it's compiled with libdevmapper
>
>
> Same result with current git as of today.
>
> [chris@f26wnuc grub]$ ./configure --build=x86_64 --host=x86_64
> --with-platform=efi
>
>
> GRUB2 will be compiled with following components:
> Platform: x86_64-efi
> With devmapper support: Yes
>
> And in the chroot:
>
> [root@localhost /]# /usr/local/sbin/grub-probe -V
> /usr/local/sbin/grub-probe (GRUB) 2.03
> [root@localhost /]# /usr/local/sbin/grub-probe -v /
> /usr/local/sbin/grub-probe: info: cannot open `/boot/grub/device.map':
> No such file or directory.
> /usr/local/sbin/grub-probe: info: changing current directory to /dev.
> /usr/local/sbin/grub-probe: info: changing current directory to v4l.
> /usr/local/sbin/grub-probe: info: changing current directory to by-path.
> /usr/local/sbin/grub-probe: info: changing current directory to by-id.
> /usr/local/sbin/grub-probe: info: changing current directory to dri.
> /usr/local/sbin/grub-probe: info: changing current directory to by-path.
> /usr/local/sbin/grub-probe: info: changing current directory to snd.
> /usr/local/sbin/grub-probe: info: changing current directory to by-path.
> /usr/local/sbin/grub-probe: info: changing current directory to vfio.
> /usr/local/sbin/grub-probe: info: changing current directory to mqueue.
> /usr/local/sbin/grub-probe: info: changing current directory to hugepages.
> /usr/local/sbin/grub-probe: info: changing current directory to disk.
> /usr/local/sbin/grub-probe: info: changing current directory to by-uuid.
> /usr/local/sbin/grub-probe: info: changing current directory to
> by-partuuid.
> /usr/local/sbin/grub-probe: info: changing current directory to
> by-partlabel.
> /usr/local/sbin/grub-probe: info: changing current directory to by-label.
> /usr/local/sbin/grub-probe: info: changing current directory to by-path.
> /usr/local/sbin/grub-probe: info: changing current directory to by-id.
> /usr/local/sbin/grub-probe: info: changing current directory to block.
> /usr/local/sbin/grub-probe: info: changing current directory to usb.
> /usr/local/sbin/grub-probe: info: changing current directory to char.
> /usr/local/sbin/grub-probe: info: changing current directory to net.
> /usr/local/sbin/grub-probe: info: changing current directory to pts.
> /usr/local/sbin/grub-probe: info: changing current directory to shm.
> /usr/local/sbin/grub-probe: info: changing current directory to bsg.
> /usr/local/sbin/grub-probe: info: changing current directory to mapper.
> /usr/local/sbin/grub-probe: info: changing current directory to input.
> /usr/local/sbin/grub-probe: info: changing current directory to by-path.
> /usr/local/sbin/grub-probe: info: changing current directory to by-id.
> /usr/local/sbin/grub-probe: info: changing current directory to bus.
> /usr/local/sbin/grub-probe: info: changing current directory to usb.
> /usr/local/sbin/grub-probe: info: changing current directory to 004.
> /usr/local/sbin/grub-probe: info: changing current directory to 003.
> /usr/local/sbin/grub-probe: info: changing current directory to 002.
> /usr/local/sbin/grub-probe: info: changing current directory to 001.
> /usr/local/sbin/grub-probe: info: changing current directory to raw.
> /usr/local/sbin/grub-probe: info: changing current directory to cpu.
> /usr/local/sbin/grub-probe: info: changing current directory to 7.
> /usr/local/sbin/grub-probe: info: changing current directory to 6.
> /usr/local/sbin/grub-probe: info: changing current directory to 5.
> /usr/local/sbin/grub-probe: info: changing current directory to 4.
> /usr/local/sbin/grub-probe: info: changing current directory to 3.
> /usr/local/sbin/grub-probe: info: changing current directory to 2.
> /usr/local/sbin/grub-probe: info: changing current directory to 1.
> /usr/local/sbin/grub-probe: info: changing current directory to 0.
> /usr/local/sbin/grub-probe: error: cannot find a device for / (is /dev
> mounted?).
> [root@localhost /]#
>
>
>
>
>
>
> --
> Chris Murphy
>

[-- Attachment #2: Type: text/html, Size: 4834 bytes --]

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: grub2-probe confused by double bind mount?
  2017-08-08  8:04       ` Vladimir 'phcoder' Serbinenko
@ 2017-08-08 23:29         ` Chris Murphy
  0 siblings, 0 replies; 7+ messages in thread
From: Chris Murphy @ 2017-08-08 23:29 UTC (permalink / raw)
  To: Vladimir 'phcoder' Serbinenko
  Cc: Chris Murphy, The development of GNU GRUB

On Tue, Aug 8, 2017 at 2:04 AM, Vladimir 'phcoder' Serbinenko
<phcoder@gmail.com> wrote:
> Did you mount /proc ? What is the contents of /proc/self/mountinfo ?

/proc is mounted. The way these ostree environments get assembled is
super messy, and I can't be sure I'm truly assembling it exactly as
the OS installer does, because the installer isn't logging the chroot
commands. However, doing my own chroot to get a cat
/proc/self/mountinfo from inside the chroot, I get a grub-probe fail
only with Btrfs not ext4.


This is mountinfo inside the chroot, with Btrfs installation.
https://pastebin.com/d2twu4qi

This is mountinfo inside the chroot, with ext4 installation.
https://pastebin.com/vqyJiNz4

This is interleaving the two mountinfo outputs, Btrfs (top line) and
ext4 (bottom line), deleting the duplicates where the two match.
https://pastebin.com/nYX71ckR

OK so there are a few discrepancies I'm seeing in this 3rd paste
showing comparisons:

1. Neither one has / in the fifth column, for mountpoint. And yet this
doesn't cause a grub-probe problem in the ext4 case. Lines 7 and 8.

2. Each Btrfs case has /root/ as a prefix for column 4, that's the
name of the subvolume the installation is put into, so it should be
OK. grub2-probe doesn't have a problem with this when it's a
conventional non-ostree installation.

3. The one thing that is kinda screwy is the mountinfo for btrfs mount
options, shows a bogus subvol= path. The kernel code shows the correct
subvolid= in each case, but the multiple bind mounts ostree is doing
is causing the kernel code to *assume* those are subvolumes when in
fact they are not. There is only one legit subvolume on this
installation and that's a subvolume named "root". So all the other
subvol= paths are not really subvolumes. I hope that makes sense...

If grub-probe does not parse for subvol= then that's not likely the
problem here.



-- 
Chris Murphy


^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2017-08-08 23:29 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-08-03  7:24 grub2-probe confused by double bind mount? Chris Murphy
2017-08-07  6:56 ` Chris Murphy
2017-08-07  7:15   ` Xen
2017-08-07 15:09   ` Vladimir 'phcoder' Serbinenko
2017-08-08  4:35     ` Chris Murphy
2017-08-08  8:04       ` Vladimir 'phcoder' Serbinenko
2017-08-08 23:29         ` Chris Murphy

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