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Message #82910
[Bug 1377142] Re: Bcache doesn't allow full unregistering without rebooting
** Description changed:
If you create a bcache device, you can't reuse all your disk/partitions
without a reboot.
You can reproduce the case this way:
start a vm with 2 disks (caching must be bigger or equal to the backing
cf bug :1377130) and an iso of utopic desktop amd64
create the bcache device:
- make-bcache --writeback --discard -C /dev/sda -B
- /dev/sdb
-
- UUID: b245150d-cfbe-4f90-836a-343e0e1a4c55
- Set UUID: c990a31a-f531-4231-9603-d40230dc6504
- version: 0
- nbuckets: 16384
- block_size: 1
- bucket_size: 1024
- nr_in_set: 1
- nr_this_dev: 0
- first_bucket: 1
- UUID: cc31e0bb-db29-4115-a1b2-e9ff54e5f127
- Set UUID: c990a31a-f531-4231-9603-d40230dc6504
- version: 1
- block_size: 1
- data_offset: 16
-
- ******************************
- command:
- lsblk
-
- result:
- NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
- sda 8:0 0 8G 0 disk
- └─bcache0 251:0 0 16G 0 disk
- sdb 8:16 0 16G 0 disk
- └─bcache0 251:0 0 16G 0 disk
- sr0 11:0 1 1,1G 0 rom /cdrom
- loop0 7:0 0 1,1G 1 loop /rofs
- ******************************
+ make-bcache --writeback --discard -C /dev/sda -B /dev/sdb
+
+ UUID: b245150d-cfbe-4f90-836a-343e0e1a4c55
+ Set UUID: c990a31a-f531-4231-9603-d40230dc6504
+ version: 0
+ nbuckets: 16384
+ block_size: 1
+ bucket_size: 1024
+ nr_in_set: 1
+ nr_this_dev: 0
+ first_bucket: 1
+ UUID: cc31e0bb-db29-4115-a1b2-e9ff54e5f127
+ Set UUID: c990a31a-f531-4231-9603-d40230dc6504
+ version: 1
+ block_size: 1
+ data_offset: 16
+
+ ******************************
+ command:
+ lsblk
+
+ result:
+ NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
+ sda 8:0 0 8G 0 disk
+ └─bcache0 251:0 0 16G 0 disk
+ sdb 8:16 0 16G 0 disk
+ └─bcache0 251:0 0 16G 0 disk
+ sr0 11:0 1 1,1G 0 rom /cdrom
+ loop0 7:0 0 1,1G 1 loop /rofs
+ ******************************
All is good
- lsmod | grep bcache:
- bcache 227884 3
+ lsmod | grep bcache:
+ bcache 227884 3
format the bcache device:
- ******************************
- command:
- mkfs.ext4 /dev/bcache0
-
- result:
- Rejet des blocs de périphérique : 4096/4194302 complété
- Creating filesystem with 4194302 4k blocks and 1048576 inodes
- Filesystem UUID: 587d2249-3eaf-4590-a00d-42939f257e99
- Superblocs de secours stockés sur les blocs :
- 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
- 4096000
-
- Allocation des tables de groupe : 0/128 complété
- Écriture des tables d'i-noeuds : 0/128 complété
- Création du journal (32768 blocs) : complété
- Écriture des superblocs et de l'information de comptabilité du système de
- fichiers : 0/128 2/128 complété
-
- ******************************
+ ******************************
+ command:
+ mkfs.ext4 /dev/bcache0
+
+ result:
+ Rejet des blocs de périphérique : 4096/4194302 complété
+ Creating filesystem with 4194302 4k blocks and 1048576 inodes
+ Filesystem UUID: 587d2249-3eaf-4590-a00d-42939f257e99
+ Superblocs de secours stockés sur les blocs :
+ 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
+ 4096000
+
+ Allocation des tables de groupe : 0/128 complété
+ Écriture des tables d'i-noeuds : 0/128 complété
+ Création du journal (32768 blocs) : complété
+ Écriture des superblocs et de l'information de comptabilité du système de
+ fichiers : 0/128 2/128 complété
+
+ ******************************
Now mount it:
- mount /dev/bcache0 /mnt/
- mkdir /mnt/test_dir
- touch /mnt/test_file
+ mount /dev/bcache0 /mnt/
+ mkdir /mnt/test_dir
+ touch /mnt/test_file
state of: /sys/fs/bcache/
- ls /sys/fs/bcache/
-
- c990a31a-f531-4231-9603-d40230dc6504
- register
- register_quiet
+ ls /sys/fs/bcache/
+
+ c990a31a-f531-4231-9603-d40230dc6504
+ register
+ register_quiet
bcache-super-show /dev/sda
- sb.magic ok
- sb.first_sector 8 [match]
- sb.csum E6A8D9AC496B0B04 [match]
- sb.version 3 [cache device]
-
- dev.label (empty)
- dev.uuid b245150d-cfbe-4f90-836a-343e0e1a4c55
- dev.sectors_per_block 1
- dev.sectors_per_bucket 1024
- dev.cache.first_sector 1024
- dev.cache.cache_sectors 16776192
- dev.cache.total_sectors 16777216
- dev.cache.ordered yes
- dev.cache.discard yes
- dev.cache.pos 0
- dev.cache.replacement 0 [lru]
-
- cset.uuid c990a31a-f531-4231-9603-d40230dc6504
- ******************************
+ sb.magic ok
+ sb.first_sector 8 [match]
+ sb.csum E6A8D9AC496B0B04 [match]
+ sb.version 3 [cache device]
+
+ dev.label (empty)
+ dev.uuid b245150d-cfbe-4f90-836a-343e0e1a4c55
+ dev.sectors_per_block 1
+ dev.sectors_per_bucket 1024
+ dev.cache.first_sector 1024
+ dev.cache.cache_sectors 16776192
+ dev.cache.total_sectors 16777216
+ dev.cache.ordered yes
+ dev.cache.discard yes
+ dev.cache.pos 0
+ dev.cache.replacement 0 [lru]
+
+ cset.uuid c990a31a-f531-4231-9603-d40230dc6504
+ ******************************
bcache-super-show -f /dev/sdb
- sb.magic ok
- sb.first_sector 8 [match]
- sb.csum 9600B159F36A67DD [match]
- sb.version 1 [backing device]
-
- dev.label (empty)
- dev.uuid cc31e0bb-db29-4115-a1b2-e9ff54e5f127
- dev.sectors_per_block 1
- dev.sectors_per_bucket 1024
- dev.data.first_sector 16
- dev.data.cache_mode 1 [writeback]
- dev.data.cache_state 2 [dirty]
-
- cset.uuid c990a31a-f531-4231-9603-d40230dc6504
- ******************************
+ sb.magic ok
+ sb.first_sector 8 [match]
+ sb.csum 9600B159F36A67DD [match]
+ sb.version 1 [backing device]
+
+ dev.label (empty)
+ dev.uuid cc31e0bb-db29-4115-a1b2-e9ff54e5f127
+ dev.sectors_per_block 1
+ dev.sectors_per_bucket 1024
+ dev.data.first_sector 16
+ dev.data.cache_mode 1 [writeback]
+ dev.data.cache_state 2 [dirty]
+
+ cset.uuid c990a31a-f531-4231-9603-d40230dc6504
+ ******************************
mount:
- /dev/bcache0 on /mnt type ext4 (rw)
+ /dev/bcache0 on /mnt type ext4 (rw)
we will unregister the bcache:
- echo 1 /sys/fs/bcache/c990a31a-f531-4231-9603-d40230dc6504/unregister
-
+ echo 1 /sys/fs/bcache/c990a31a-f531-4231-9603-d40230dc6504/unregister
check the content of /sys/fs/bcache
- ls /sys/fs/bcache/
-
- register
- register_quiet
+ ls /sys/fs/bcache/
+
+ register
+ register_quiet
So bcache is unregistered, but status of /dev/sda:
- bcache-super-show -f /dev/sda
- sb.magic ok
- sb.first_sector 8 [match]
- sb.csum E6A8D9AC496B0B04 [match]
- sb.version 3 [cache device]
-
- dev.label (empty)
- dev.uuid b245150d-cfbe-4f90-836a-343e0e1a4c55
- dev.sectors_per_block 1
- dev.sectors_per_bucket 1024
- dev.cache.first_sector 1024
- dev.cache.cache_sectors 16776192
- dev.cache.total_sectors 16777216
- dev.cache.ordered yes
- dev.cache.discard yes
- dev.cache.pos 0
- dev.cache.replacement 0 [lru]
-
- cset.uuid
- c990a31a-f531-4231-9603-d40230dc6504
-
-
- command:
- bcache-super-show -f /dev/sdb
-
- result:
- sb.magic ok
- sb.first_sector 8 [match]
- sb.csum D41799F794675FA8 [match]
- sb.version 1 [backing device]
-
- dev.label (empty)
- dev.uuid cc31e0bb-db29-4115-a1b2-e9ff54e5f127
- dev.sectors_per_block 1
- dev.sectors_per_bucket 1024
- dev.data.first_sector 16
- dev.data.cache_mode 1 [writeback]
- dev.data.cache_state 0 [detached]
-
- cset.uuid 00000000-0000-0000-0000-000000000000
- ******************************
+ bcache-super-show -f /dev/sda
+ sb.magic ok
+ sb.first_sector 8 [match]
+ sb.csum E6A8D9AC496B0B04 [match]
+ sb.version 3 [cache device]
+
+ dev.label (empty)
+ dev.uuid b245150d-cfbe-4f90-836a-343e0e1a4c55
+ dev.sectors_per_block 1
+ dev.sectors_per_bucket 1024
+ dev.cache.first_sector 1024
+ dev.cache.cache_sectors 16776192
+ dev.cache.total_sectors 16777216
+ dev.cache.ordered yes
+ dev.cache.discard yes
+ dev.cache.pos 0
+ dev.cache.replacement 0 [lru]
+
+ cset.uuid c990a31a-f531-4231-9603-d40230dc6504
+
+ command:
+ bcache-super-show -f /dev/sdb
+
+ result:
+ sb.magic ok
+ sb.first_sector 8 [match]
+ sb.csum D41799F794675FA8 [match]
+ sb.version 1 [backing device]
+
+ dev.label (empty)
+ dev.uuid cc31e0bb-db29-4115-a1b2-e9ff54e5f127
+ dev.sectors_per_block 1
+ dev.sectors_per_bucket 1024
+ dev.data.first_sector 16
+ dev.data.cache_mode 1 [writeback]
+ dev.data.cache_state 0 [detached]
+
+ cset.uuid 00000000-0000-0000-0000-000000000000
+ ******************************
Maybe I'm wrong, but I would expect the cahing device to be 000000000ed
not the backing device, as we may still want to use the data on it.
But data is still accessible on the mount point.
- So we wipe /dev/sda now:
- ******************************
- command:
- wipefs -a /dev/sda
-
- result:
- /dev/sda: 16 bytes were erased at offset 0x00001018 (bcache): c6 85 73 f6 4e 1a 45 ca 82 65 f5 7f 48 ba 6d 81
- ******************************
+ So we wipe /dev/sda now:
+ ******************************
+ command:
+ wipefs -a /dev/sda
+
+ result:
+ /dev/sda: 16 bytes were erased at offset 0x00001018 (bcache): c6 85 73 f6 4e 1a 45 ca 82 65 f5 7f 48 ba 6d 81
+ ******************************
mount:
- /dev/bcache0 on /mnt type ext4 (rw)
+ /dev/bcache0 on /mnt type ext4 (rw)
data still there:
- ******************************
- command:
- ls /mnt/
-
- result:
- lost+found
- test_dir
- test_file
- ******************************
-
- ******************************
- command:
- lsblk
-
- result:
- NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
- sda 8:0 0 8G 0 disk
- sdb 8:16 0 16G 0 disk
- └─bcache0 251:0 0 16G 0 disk /mnt
- sr0 11:0 1 1,1G 0 rom /cdrom
- loop0 7:0 0 1,1G 1 loop /rofs
- ******************************
+ ******************************
+ command:
+ ls /mnt/
+
+ result:
+ lost+found
+ test_dir
+ test_file
+ ******************************
+
+ ******************************
+ command:
+ lsblk
+
+ result:
+ NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
+ sda 8:0 0 8G 0 disk
+ sdb 8:16 0 16G 0 disk
+ └─bcache0 251:0 0 16G 0 disk /mnt
+ sr0 11:0 1 1,1G 0 rom /cdrom
+ loop0 7:0 0 1,1G 1 loop /rofs
+ ******************************
Ok now we can backup our data if we need to, next, we will umount:
- umount /mnt/
+ umount /mnt/
ok no errors.
- lsblk:
- NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
- sda 8:0 0 8G 0 disk
- sdb 8:16 0 16G 0 disk
- └─bcache0 251:0 0 16G 0 disk
- sr0 11:0 1 1,1G 0 rom /cdrom
- loop0 7:0 0 1,1G 1 loop /rofs
- ******************************
+ lsblk:
+ NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
+ sda 8:0 0 8G 0 disk
+ sdb 8:16 0 16G 0 disk
+ └─bcache0 251:0 0 16G 0 disk
+ sr0 11:0 1 1,1G 0 rom /cdrom
+ loop0 7:0 0 1,1G 1 loop /rofs
+ ******************************
bcache0 is still there, ok, but how to delete to unregister it
definitively?
- ls /sys/fs/bcache/
-
- result:
- register
- register_quiet
- **************
-
- lsmod
-
- result:
- Module Size Used by
- bcache 227884 1
+ ls /sys/fs/bcache/
+
+ result:
+ register
+ register_quiet
+ **************
+
+ lsmod
+
+ result:
+ Module Size Used by
+ bcache 227884 1
we can't wipefs -a /dev/sdb, device is in use, so we reboot machine (NOT
OK)
- in the vm:
- ls /sys/fs/bcache/
-
- result:
- register
- register_quiet
+ in the vm:
+ ls /sys/fs/bcache/
+
+ result:
+ register
+ register_quiet
update packages and reinstall bcache-tools:
- bcache-super-show -f /dev/sda
-
- result:
- Invalid superblock (bad magic)
- sb.magic bad magic
-
- bcache-super-show -f /dev/sdb
-
- result:
- sb.magic ok
- sb.first_sector 8 [match]
- sb.csum D41799F794675FA8 [match]
- sb.version 1 [backing device]
-
- dev.label (empty)
- dev.uuid cc31e0bb-db29-4115-a1b2-e9ff54e5f127
- dev.sectors_per_block 1
- dev.sectors_per_bucket 1024
- dev.data.first_sector 16
- dev.data.cache_mode 1 [writeback]
- dev.data.cache_state 0 [detached]
-
- cset.uuid
- 00000000-0000-0000-0000-000000000000
+ bcache-super-show -f /dev/sda
+
+ result:
+ Invalid superblock (bad magic)
+ sb.magic bad magic
+
+ bcache-super-show -f /dev/sdb
+
+ result:
+ sb.magic ok
+ sb.first_sector 8 [match]
+ sb.csum D41799F794675FA8 [match]
+ sb.version 1 [backing device]
+
+ dev.label (empty)
+ dev.uuid cc31e0bb-db29-4115-a1b2-e9ff54e5f127
+ dev.sectors_per_block 1
+ dev.sectors_per_bucket 1024
+ dev.data.first_sector 16
+ dev.data.cache_mode 1 [writeback]
+ dev.data.cache_state 0 [detached]
+
+ cset.uuid 00000000-0000-0000-0000-000000000000
Now we can wipe /dev/sdb because we rebooted, and bcache don't use the device anymore:
- wipefs -a /dev/sdb
-
- result:
- /dev/sdb: 16 bytes were erased at offset 0x00001018 (bcache): c6 85 73 f6 4e 1a 45 ca 82 65 f5 7f 48 ba 6d 81
-
- **********************************************************
-
- Now I can re-use my device, but I needed a reboot. Maybe we must also
- have better bcache management tools also.
+ wipefs -a /dev/sdb
+
+ result:
+ /dev/sdb: 16 bytes were erased at offset 0x00001018 (bcache): c6 85 73 f6 4e 1a 45 ca 82 65 f5 7f 48 ba 6d 81
+
+ **********************************************************
+
+ Now I can re-use my device, but I needed a reboot. Maybe we also must
+ have better bcache management tools.
--
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https://bugs.launchpad.net/bugs/1377142
Title:
Bcache doesn't allow full unregistering without rebooting
Status in “bcache-tools” package in Ubuntu:
New
Status in “linux” package in Ubuntu:
Incomplete
Bug description:
If you create a bcache device, you can't reuse all your
disk/partitions without a reboot.
You can reproduce the case this way:
start a vm with 2 disks (caching must be bigger or equal to the
backing cf bug :1377130) and an iso of utopic desktop amd64
create the bcache device:
make-bcache --writeback --discard -C /dev/sda -B /dev/sdb
UUID: b245150d-cfbe-4f90-836a-343e0e1a4c55
Set UUID: c990a31a-f531-4231-9603-d40230dc6504
version: 0
nbuckets: 16384
block_size: 1
bucket_size: 1024
nr_in_set: 1
nr_this_dev: 0
first_bucket: 1
UUID: cc31e0bb-db29-4115-a1b2-e9ff54e5f127
Set UUID: c990a31a-f531-4231-9603-d40230dc6504
version: 1
block_size: 1
data_offset: 16
******************************
command:
lsblk
result:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 8G 0 disk
└─bcache0 251:0 0 16G 0 disk
sdb 8:16 0 16G 0 disk
└─bcache0 251:0 0 16G 0 disk
sr0 11:0 1 1,1G 0 rom /cdrom
loop0 7:0 0 1,1G 1 loop /rofs
******************************
All is good
lsmod | grep bcache:
bcache 227884 3
format the bcache device:
******************************
command:
mkfs.ext4 /dev/bcache0
result:
Rejet des blocs de périphérique : 4096/4194302 complété
Creating filesystem with 4194302 4k blocks and 1048576 inodes
Filesystem UUID: 587d2249-3eaf-4590-a00d-42939f257e99
Superblocs de secours stockés sur les blocs :
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000
Allocation des tables de groupe : 0/128 complété
Écriture des tables d'i-noeuds : 0/128 complété
Création du journal (32768 blocs) : complété
Écriture des superblocs et de l'information de comptabilité du système de
fichiers : 0/128 2/128 complété
******************************
Now mount it:
mount /dev/bcache0 /mnt/
mkdir /mnt/test_dir
touch /mnt/test_file
state of: /sys/fs/bcache/
ls /sys/fs/bcache/
c990a31a-f531-4231-9603-d40230dc6504
register
register_quiet
bcache-super-show /dev/sda
sb.magic ok
sb.first_sector 8 [match]
sb.csum E6A8D9AC496B0B04 [match]
sb.version 3 [cache device]
dev.label (empty)
dev.uuid b245150d-cfbe-4f90-836a-343e0e1a4c55
dev.sectors_per_block 1
dev.sectors_per_bucket 1024
dev.cache.first_sector 1024
dev.cache.cache_sectors 16776192
dev.cache.total_sectors 16777216
dev.cache.ordered yes
dev.cache.discard yes
dev.cache.pos 0
dev.cache.replacement 0 [lru]
cset.uuid c990a31a-f531-4231-9603-d40230dc6504
******************************
bcache-super-show -f /dev/sdb
sb.magic ok
sb.first_sector 8 [match]
sb.csum 9600B159F36A67DD [match]
sb.version 1 [backing device]
dev.label (empty)
dev.uuid cc31e0bb-db29-4115-a1b2-e9ff54e5f127
dev.sectors_per_block 1
dev.sectors_per_bucket 1024
dev.data.first_sector 16
dev.data.cache_mode 1 [writeback]
dev.data.cache_state 2 [dirty]
cset.uuid c990a31a-f531-4231-9603-d40230dc6504
******************************
mount:
/dev/bcache0 on /mnt type ext4 (rw)
we will unregister the bcache:
echo 1 /sys/fs/bcache/c990a31a-f531-4231-9603-d40230dc6504/unregister
check the content of /sys/fs/bcache
ls /sys/fs/bcache/
register
register_quiet
So bcache is unregistered, but status of /dev/sda:
bcache-super-show -f /dev/sda
sb.magic ok
sb.first_sector 8 [match]
sb.csum E6A8D9AC496B0B04 [match]
sb.version 3 [cache device]
dev.label (empty)
dev.uuid b245150d-cfbe-4f90-836a-343e0e1a4c55
dev.sectors_per_block 1
dev.sectors_per_bucket 1024
dev.cache.first_sector 1024
dev.cache.cache_sectors 16776192
dev.cache.total_sectors 16777216
dev.cache.ordered yes
dev.cache.discard yes
dev.cache.pos 0
dev.cache.replacement 0 [lru]
cset.uuid c990a31a-f531-4231-9603-d40230dc6504
command:
bcache-super-show -f /dev/sdb
result:
sb.magic ok
sb.first_sector 8 [match]
sb.csum D41799F794675FA8 [match]
sb.version 1 [backing device]
dev.label (empty)
dev.uuid cc31e0bb-db29-4115-a1b2-e9ff54e5f127
dev.sectors_per_block 1
dev.sectors_per_bucket 1024
dev.data.first_sector 16
dev.data.cache_mode 1 [writeback]
dev.data.cache_state 0 [detached]
cset.uuid 00000000-0000-0000-0000-000000000000
******************************
Maybe I'm wrong, but I would expect the cahing device to be
000000000ed not the backing device, as we may still want to use the
data on it.
But data is still accessible on the mount point.
So we wipe /dev/sda now:
******************************
command:
wipefs -a /dev/sda
result:
/dev/sda: 16 bytes were erased at offset 0x00001018 (bcache): c6 85 73 f6 4e 1a 45 ca 82 65 f5 7f 48 ba 6d 81
******************************
mount:
/dev/bcache0 on /mnt type ext4 (rw)
data still there:
******************************
command:
ls /mnt/
result:
lost+found
test_dir
test_file
******************************
******************************
command:
lsblk
result:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 8G 0 disk
sdb 8:16 0 16G 0 disk
└─bcache0 251:0 0 16G 0 disk /mnt
sr0 11:0 1 1,1G 0 rom /cdrom
loop0 7:0 0 1,1G 1 loop /rofs
******************************
Ok now we can backup our data if we need to, next, we will umount:
umount /mnt/
ok no errors.
lsblk:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 8G 0 disk
sdb 8:16 0 16G 0 disk
└─bcache0 251:0 0 16G 0 disk
sr0 11:0 1 1,1G 0 rom /cdrom
loop0 7:0 0 1,1G 1 loop /rofs
******************************
bcache0 is still there, ok, but how to delete to unregister it
definitively?
ls /sys/fs/bcache/
result:
register
register_quiet
**************
lsmod
result:
Module Size Used by
bcache 227884 1
we can't wipefs -a /dev/sdb, device is in use, so we reboot machine
(NOT OK)
in the vm:
ls /sys/fs/bcache/
result:
register
register_quiet
update packages and reinstall bcache-tools:
bcache-super-show -f /dev/sda
result:
Invalid superblock (bad magic)
sb.magic bad magic
bcache-super-show -f /dev/sdb
result:
sb.magic ok
sb.first_sector 8 [match]
sb.csum D41799F794675FA8 [match]
sb.version 1 [backing device]
dev.label (empty)
dev.uuid cc31e0bb-db29-4115-a1b2-e9ff54e5f127
dev.sectors_per_block 1
dev.sectors_per_bucket 1024
dev.data.first_sector 16
dev.data.cache_mode 1 [writeback]
dev.data.cache_state 0 [detached]
cset.uuid 00000000-0000-0000-0000-000000000000
Now we can wipe /dev/sdb because we rebooted, and bcache don't use the device anymore:
wipefs -a /dev/sdb
result:
/dev/sdb: 16 bytes were erased at offset 0x00001018 (bcache): c6 85 73 f6 4e 1a 45 ca 82 65 f5 7f 48 ba 6d 81
**********************************************************
Now I can re-use my device, but I needed a reboot. Maybe we also must
have better bcache management tools.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/bcache-tools/+bug/1377142/+subscriptions
References
