Description of problem:
When writing to and deleting data from LVMVDO volume, the volume does not
reclaim the space freed by data deletion. When checking volume space
utilization via `lvs', "Data%" value is never decresed (but e.g. `df' command
does reflect the data deletion and reports expected values). Eventually, when
"Data%" value of `vdo_pool' becomes 100.00, LVMVDO volume ends up in read-only
mode and `fsck' reports an filesystem error.


Version-Release number of selected component (if applicable):
lvm2-2.03.08-3.el8.x86_64 (RHEL 8.2.1)
lvm2-2.03.09-2.el8.x86_64 (RHEL 8.3.0)
(other versions were not tested)


How reproducible:
always (see steps below)


Steps to Reproduce:
prerequisites: 3 disks, 5GB each
1. pvcreate /dev/sd{a,b,c}
2. vgcreate vdovg /dev/sd{a,b,c}
3. lvcreate --type vdo -n vdolv -L 10G -V 20G vdovg/vdo_pool
4. mkfs.ext4 -E nodiscard /dev/vdovg/vdolv
5. mkdir /mnt/vdolv
6. mount /dev/vdovg/vdolv /mnt/vdolv/
*  check logical volumes stats using `lvs' and `df -h' 
7. dd if=/dev/urandom of=/mnt/vdolv/urandom_data.bin bs=1G count=5 iflag=fullblock
   # the overall result is exactly the same result if you copy the random
   # data using `cp' instead of writing them directly using `dd' command
*  check logical volumes stats using `lvs' and `df -h'
8. rm /mnt/vdolv/urandom_data.bin
*  check logical volumes stats using `lvs' and `df -h'
9. repeat step #7


Actual results:
dd: error writing '/mnt/vdolv/urandom_data.bin': Read-only file system
2+0 records in
1+0 records out 
1384009728 bytes (1.4 GB, 1.3 GiB) copied, 41.5512 s, 33.3 MB/s

[root@virt-175 ~]# lvs 
  LV       VG            Attr       LSize   Pool     Origin Data%  Meta%  Move Log Cpy%Sync Convert
  root     rhel_virt-175 -wi-ao----  <6.20g
  swap     rhel_virt-175 -wi-ao---- 820.00m
  vdo_pool vdovg         dwi-------  10.00g                 100.00
  vdolv    vdovg         vwi-aov---  20.00g vdo_pool        29.94

[root@virt-175 ~]# df -h
Filesystem                       Size  Used Avail Use% Mounted on
devtmpfs                         991M     0  991M   0% /dev
tmpfs                           1011M     0 1011M   0% /dev/shm
tmpfs                           1011M   22M  989M   3% /run
tmpfs                           1011M     0 1011M   0% /sys/fs/cgroup
/dev/mapper/rhel_virt--175-root  6.2G  3.1G  3.2G  49% /
/dev/vda1                       1014M  194M  821M  20% /boot
tmpfs                            202M     0  202M   0% /run/user/0
/dev/mapper/vdovg-vdolv           20G  1.4G   18G   8% /mnt/vdolv

[root@virt-175 ~]# umount /mnt/vdolv/
[root@virt-175 ~]# fsck.ext4 /dev/vdovg/vdolv
e2fsck 1.45.4 (23-Sep-2019)
/dev/vdovg/vdolv: recovering journal
Superblock needs_recovery flag is clear, but journal has data.
Run journal anyway<y>? yes
fsck.ext4: unable to set superblock flags on /dev/vdovg/vdolv


/dev/vdovg/vdolv: ********** WARNING: Filesystem still has errors **********


Expected results:
All data (5GB) has been written. `vdolv' volume is available for further use.