Hello

[root@storageqe-24 ~]# vgcreate snapper_thinp  /dev/sdc
[root@storageqe-24 ~]# lvcreate --thinpool POOL --zero n -L 1G snapper_thinp 
  Thin pool volume with chunk size 64.00 KiB can address at most 15.81 TiB of data.
  Logical volume "POOL" created.

[root@storageqe-24 ~]# lvcreate  --virtualsize 1G -T snapper_thinp/POOL -n origin 
  Logical volume "origin" created.
[root@storageqe-24 ~]# echo Str0ngP455w0rd### | cryptsetup luksFormat /dev/snapper_thinp/origin 
[root@storageqe-24 ~]# echo Str0ngP455w0rd### | cryptsetup luksOpen --disable-keyring /dev/snapper_thinp/origin luks_origin  

[root@storageqe-24 ~]#  mkfs.ext4 /dev/mapper/luks_origin
mke2fs 1.44.6 (5-Mar-2019)
Creating filesystem with 258048 4k blocks and 64512 inodes
Filesystem UUID: e8d48b20-555d-4403-b6d1-35ab0effda53
Superblock backups stored on blocks: 
	32768, 98304, 163840, 229376

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done

[root@storageqe-24 ~]# lvextend -L +500M -r /dev/snapper_thinp/origin
fsck from util-linux 2.32.1
/dev/mapper/luks_origin: clean, 11/64512 files, 8785/258048 blocks
  WARNING: Sum of all thin volume sizes (<1.49 GiB) exceeds the size of thin pool snapper_thinp/POOL (1.00 GiB).
  WARNING: You have not turned on protection against thin pools running out of space.
  WARNING: Set activation/thin_pool_autoextend_threshold below 100 to trigger automatic extension of thin pools before they get full.
  Size of logical volume snapper_thinp/origin changed from 1.00 GiB (256 extents) to <1.49 GiB (381 extents).
  Logical volume snapper_thinp/origin successfully resized.
resize2fs 1.44.6 (5-Mar-2019)
Resizing the filesystem on /dev/mapper/luks_origin to 386048 (4k) blocks.
The filesystem on /dev/mapper/luks_origin is now 386048 (4k) blocks long.

[root@storageqe-24 ~]# mkdir -p /mnt/origin
[root@storageqe-24 ~]# 
[root@storageqe-24 ~]# mount /dev/mapper/luks_origin /mnt/origin/
[root@storageqe-24 ~]# 
[root@storageqe-24 ~]# df -h
Filesystem                           Size  Used Avail Use% Mounted on
devtmpfs                              32G   10M   32G   1% /dev
tmpfs                                 32G     0   32G   0% /dev/shm
tmpfs                                 32G   26M   32G   1% /run
tmpfs                                 32G     0   32G   0% /sys/fs/cgroup
/dev/mapper/rhel_storageqe--24-root   50G  3.3G   47G   7% /
/dev/sda2                           1014M  165M  850M  17% /boot
/dev/mapper/rhel_storageqe--24-home  5.4T   39G  5.4T   1% /home
tmpfs                                6.3G     0  6.3G   0% /run/user/0
/dev/mapper/luks_origin              1.5G  3.0M  1.4G   1% /mnt/origin
[root@storageqe-24 ~]# lvextend -L +500M -r /dev/snapper_thinp/origin
  WARNING: Sum of all thin volume sizes (<1.98 GiB) exceeds the size of thin pool snapper_thinp/POOL (1.00 GiB).
  WARNING: You have not turned on protection against thin pools running out of space.
  WARNING: Set activation/thin_pool_autoextend_threshold below 100 to trigger automatic extension of thin pools before they get full.
  Size of logical volume snapper_thinp/origin changed from <1.49 GiB (381 extents) to <1.98 GiB (506 extents).
  Logical volume snapper_thinp/origin successfully resized.
resize2fs 1.44.6 (5-Mar-2019)
Filesystem at /dev/mapper/luks_origin is mounted on /mnt/origin; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 1
The filesystem on /dev/mapper/luks_origin is now 514048 (4k) blocks long.

[root@storageqe-24 ~]# echo Str0ngP455w0rd### | cryptsetup reencrypt --resilience none --active-name luks_origin
Progress:  44.8%, ETA 00:07,  900 MiB written, speed 141.3 MiB/sFailed to write hotzone area starting at 996147200.
Fatal error while reencrypting chunk starting at 1978368, 102400 sectors long.
Reencryption was run in online mode.
[root@storageqe-24 ~]# lvextend -L +500M -r /dev/snapper_thinp/origin
fsadm: Can not find active LUKS device. Unlock "/dev/mapper/snapper_thinp-origin" volume first.
  Filesystem check failed.

HI, 

please have a look the error if expectation ?

The LV 'origin' is twice the size of thin pool. During reencryption the whole device gets written and therefore it can't fit in the thin pool. This works as expected.

Perhaps you can simplify test for this bug:

The bug is in the fact that online reencryption completely ignored user's preference of using --disable-keyring option during device activation.
So you can perhaps just activate the device with

"cryptsetup open /your/device crypt_mapping --disable-keyring"

Later, "cryptsetup status crypt_mapping" should show following output:
(....)
  key location: dm-crypt   <====== here
(...)
  sector size:  512
  offset:  4096 sectors
  size:    293597184 sectors
  mode:    read/write
  flags:   discards

If you reencrypt the device you just need to verify that key remained in dm-crypt after the operation got finished. It should be in dm-crypt for the whole duration of reencryption operation, by the way. You can check the same also with "dmsetup table crypt_mapping --showkeys". The key loaded via kernel keyring will look like ":64:logon:cryptsetup:b85...." whereas key loaded directly in dm-crypt will manifest in plain hexbyte represenation of binary volume key.

thanks Ondrej for the details, move to verified

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2020:1848