[dm-crypt] force luksClose

[yac <yac@blesmrt.net>]

Hello

I believe I have the same problem as described here:
http://comments.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/6250

Here are the last requested commands:

# dmsetup table dlt
0 4096 crypt aes-xts-plain64 0000000000000000000000000000000000000000000000000000000000000000 0 254:8 4096
# dmsetup info -c dlt
Name             Maj Min Stat Open Targ Event  UUID                                            
dlt              254   9 L--w    1    1      0 CRYPT-LUKS1-731df69c78e94882982899390c71bb3b-dlt
# lsblk 
lsblk: dm-0: failed to get device path
lsblk: dm-0: failed to get device path
NAME                MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINT
sda                   8:0    0  1.8T  0 disk  
└─sda1                8:1    0  1.8T  0 part  
sdb                   8:16   0  2.7T  0 disk  
└─sdb1                8:17   0  2.7T  0 part  
sdc                   8:32   0  2.7T  0 disk  
└─sdc1                8:33   0  2.7T  0 part  
sdd                   8:48   0  2.7T  0 disk  
└─sdd1                8:49   0  2.7T  0 part  
sde                   8:64   0  2.7T  0 disk  
└─sde1                8:65   0  2.7T  0 part  
sdf                   8:80   0  1.8T  0 disk  
sdg                   8:96   1  3.8G  0 disk  
└─sdg1                8:97   1  3.8G  0 part  
loop8                 7:8    0   10M  0 loop  
├─lt-lvol0_rmeta_0  254:4    0    4M  0 lvm   
│ └─lt-lvol0        254:8    0    4M  0 lvm   
│   └─dlt           254:9    0    2M  0 crypt /root/lvm-crypt-test/mnt
└─lt-lvol0_rimage_0 254:5    0   12M  0 lvm   
  └─lt-lvol0        254:8    0    4M  0 lvm   
    └─dlt           254:9    0    2M  0 crypt /root/lvm-crypt-test/mnt
loop9                 7:9    0   10M  0 loop  
├─lt-lvol0_rmeta_1  254:6    0    4M  0 lvm   
│ └─lt-lvol0        254:8    0    4M  0 lvm   
│   └─dlt           254:9    0    2M  0 crypt /root/lvm-crypt-test/mnt
└─lt-lvol0_rimage_1 254:7    0   12M  0 lvm   
  └─lt-lvol0        254:8    0    4M  0 lvm   
    └─dlt           254:9    0    2M  0 crypt /root/lvm-crypt-test/mnt
loop10                7:10   0   10M  0 loop  
└─lt-lvol0_rimage_0 254:5    0   12M  0 lvm   
  └─lt-lvol0        254:8    0    4M  0 lvm   
    └─dlt           254:9    0    2M  0 crypt /root/lvm-crypt-test/mnt
loop11                7:11   0   10M  0 loop  
└─lt-lvol0_rimage_1 254:7    0   12M  0 lvm   
  └─lt-lvol0        254:8    0    4M  0 lvm   
    └─dlt           254:9    0    2M  0 crypt /root/lvm-crypt-test/mnt



This happened to me after I was trying out lvm and then crypt on top
lvm. First, let's have a workspace

# cd /root; mkdir lvm-crypt-test; cd lvm-crypt-test

Fake some block devs

# mknod /dev/lta b 7 8
# mknod /dev/ltb b 7 9
# mknod /dev/ltc b 7 10 
# mknod /dev/ltd b 7 11
# for i in a b c d; do fallocate -l 10M sd$i; losetup /dev/lt$i sd$i; done

Make an LVM raid1

# pvcreate /dev/lt{a,b,c,d}
# vgcreate lt /dev/lt{a,b,c,d}
# lvcreate -m1 -l 100%VG lt /dev/lt{a,b}

Encrypt it

# echo "aaa" > key
# cryptsetup luksFormat /dev/lt/lvol0 -d key

Format and mount

# cryptsetup luksOpen /dev/lt/lvol0 -d key dlt
# mkfs.ext4 /dev/mapper/dlt
# mkdir ./mnt; mount /dev/mapper/dlt ./mnt

Now comes the part where I broke it

# lvextend /dev/lt/lvol0 /dev/lt{c,d} -l 100%VG

I tried to umount mnt but it got stuck in uninterruptible sleep. But
umount -l worked for me.

# cat /proc/mounts  | grep dlt
# cat /proc/mounts  | grep mnt
# 

But I am not able to anything about dlt and the underlying devices. Not
even turn the system off normally as that gets stuck on sync().

# ps auxf | grep D
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root     15193  0.0  0.0  27488  4436 ?        D    01:03   0:00 lvs
root     15196  0.0  0.0  27472  4432 ?        D    01:04   0:00 lvdisplay
root     15201  0.0  0.0  12612  2300 ?        D    01:04   0:00 umount mnt/
root     15237  0.0  0.0  12564  1740 ?        D    01:06   0:00 shutdown -h 0 w
root     15372  0.0  0.0   5840   748 ?        D    01:12   0:00 sync
root     17287  0.0  0.0   4016   640 ?        D    01:50   0:00 /sbin/reboot -f
root     17296  0.0  0.0  12576  2512 ?        D    01:51   0:00 dmsetup remove -f dlt
root     25471  0.0  0.0  27480  4532 ?        D    02:05   0:00 lvchange -an /dev/lt/lvol0
root     25529  0.0  0.0  24008  5576 ?        D<L  02:15   0:00 cryptsetup luksClose dlt
root     26114  0.0  0.0  24008  5576 ?        D<L  03:21   0:00 cryptsetup loopaesClose dlt

# lsof /root/lvm-crypt-test/mnt/
# fuser /root/lvm-crypt-test/mnt/
# find /proc/ -maxdepth 2 -type l -name cwd -exec readlink {} \; | sort | uniq
/
/proc/26289
/root
/root/lvm-crypt-test
/sys


Luckily I was able to umount and luksClose all the real block devices
there and now it appears my only option is to go pull the plug.

Best regards
Jan Matejka