ZFS snapshot - rollback problem

[Ludovit Koren]

Hi,

I have the following configuration:

~>uname -a
FreeBSD XxX 11.3-STABLE FreeBSD 11.3-STABLE #1 r354607: Mon Nov 11
12:19:28 CET 2019     root at jedi:/usr/obj/usr/src/sys/HP  amd64
~>zfs list
NAME              USED  AVAIL  REFER  MOUNTPOINT
zroot             244G      0  10.7G  /mnt
zroot/Centos8    6.80G  4.13G  2.67G  -
zroot/msw7       44.9G  25.8G  19.1G  -
zroot/swapdisk0  40.8G  20.6G  20.2G  -
zroot/usr         131G      0  50.9G  /usr
zroot/usr/home   80.1G      0  80.1G  /usr/home
zroot/var        9.94G      0  9.94G  /var

After zfs snapshot, which I did on the root, I got:
~>zfs list -t snapshot
NAME                     USED  AVAIL  REFER  MOUNTPOINT
zroot at 200909               1K      -  10.7G  -
zroot/Centos8 at 200909       1K      -  2.67G  -
zroot/msw7 at 200909          1K      -  19.1G  -
zroot/swapdisk0 at 200909      0      -  20.2G  -
zroot/usr at 200909           1K      -  50.9G  -
zroot/usr/home at 200909      1K      -  80.1G  -
zroot/var at 200909           1K      -  9.94G  -

i.e. whole filesystem is read only. I am not able to do neither
rollback, nor destroy of the snapshot. Is there any possibility to
reset the filesystem to the read-write mode?


Any help is greatly appreciated.


Regards,


lk