Unable to destroy zfs snapshot - dataset is busy

[yusing]

System information

Type	Version/Name
Distribution Name	Proxmox
Distribution Version	8.4.1
Kernel Version	6.8.12-9-pve
Architecture	x86_64
OpenZFS Version	zfs-2.2.7-pve2, zfs-kmod-2.2.7-pve2

Describe the problem you're observing

cannot destroy snapshot <snapshot>: dataset is busy

Describe how to reproduce the problem

zfs destroy -vrf rpool/data/subvol-119-disk-0

Include any warning/errors/backtraces from the system logs

root@pve:~# zfs destroy rpool/data/subvol-119-disk-0@restic-20250406-030001
cannot destroy snapshot rpool/data/subvol-119-disk-0@restic-20250406-030001: dataset is busy

root@pve:~# zfs destroy -vrf rpool/data/subvol-119-disk-0
will destroy rpool/data/subvol-119-disk-0@restic-20250406-030001
will destroy rpool/data/subvol-119-disk-0@restic-20250409-030001
will destroy rpool/data/subvol-119-disk-0
cannot destroy snapshot rpool/data/subvol-119-disk-0@restic-20250406-030001: dataset is busy
cannot destroy snapshot rpool/data/subvol-119-disk-0@restic-20250409-030001: dataset is busy

root@pve:~# grep subvol-119-disk-0 /proc/*/mounts
# no output

root@pve:~# zfs list -t snapshot -o name,refer,mountpoint,used,creation rpool/data/subvol-119-disk-0
NAME                                                 REFER  MOUNTPOINT   USED  CREATION
rpool/data/subvol-119-disk-0@restic-20250406-030001   122G  -           2.03G  Sun Apr  6  3:00 2025
rpool/data/subvol-119-disk-0@restic-20250409-030001   123G  -           1.32G  Wed Apr  9  3:00 2025

root@pve:~# zfs list -r -o name,mountpoint,origin rpool/data/subvol-119-disk-0
NAME                          MOUNTPOINT  ORIGIN
rpool/data/subvol-119-disk-0  none

root@pve:~# zfs get all rpool/data/subvol-119-disk-0
NAME                          PROPERTY              VALUE                     SOURCE
rpool/data/subvol-119-disk-0  type                  filesystem                -
rpool/data/subvol-119-disk-0  creation              Sat Mar 16 10:49 2024     -
rpool/data/subvol-119-disk-0  used                  143G                      -
rpool/data/subvol-119-disk-0  available             414G                      -
rpool/data/subvol-119-disk-0  referenced            108G                      -
rpool/data/subvol-119-disk-0  compressratio         1.35x                     -
rpool/data/subvol-119-disk-0  mounted               no                        -
rpool/data/subvol-119-disk-0  quota                 none                      default
rpool/data/subvol-119-disk-0  reservation           none                      default
rpool/data/subvol-119-disk-0  recordsize            8K                        inherited from rpool
rpool/data/subvol-119-disk-0  mountpoint            none                      local
rpool/data/subvol-119-disk-0  sharenfs              off                       default
rpool/data/subvol-119-disk-0  checksum              on                        default
rpool/data/subvol-119-disk-0  compression           zstd                      inherited from rpool
rpool/data/subvol-119-disk-0  atime                 on                        inherited from rpool
rpool/data/subvol-119-disk-0  devices               on                        default
rpool/data/subvol-119-disk-0  exec                  on                        default
rpool/data/subvol-119-disk-0  setuid                on                        default
rpool/data/subvol-119-disk-0  readonly              off                       default
rpool/data/subvol-119-disk-0  zoned                 off                       default
rpool/data/subvol-119-disk-0  snapdir               hidden                    default
rpool/data/subvol-119-disk-0  aclmode               discard                   default
rpool/data/subvol-119-disk-0  aclinherit            restricted                default
rpool/data/subvol-119-disk-0  createtxg             168995                    -
rpool/data/subvol-119-disk-0  canmount              off                       local
rpool/data/subvol-119-disk-0  xattr                 sa                        local
rpool/data/subvol-119-disk-0  copies                1                         default
rpool/data/subvol-119-disk-0  version               5                         -
rpool/data/subvol-119-disk-0  utf8only              off                       -
rpool/data/subvol-119-disk-0  normalization         none                      -
rpool/data/subvol-119-disk-0  casesensitivity       sensitive                 -
rpool/data/subvol-119-disk-0  vscan                 off                       default
rpool/data/subvol-119-disk-0  nbmand                off                       default
rpool/data/subvol-119-disk-0  sharesmb              off                       default
rpool/data/subvol-119-disk-0  refquota              550G                      local
rpool/data/subvol-119-disk-0  refreservation        none                      default
rpool/data/subvol-119-disk-0  guid                  10459222805264121475      -
rpool/data/subvol-119-disk-0  primarycache          all                       default
rpool/data/subvol-119-disk-0  secondarycache        all                       default
rpool/data/subvol-119-disk-0  usedbysnapshots       35.1G                     -
rpool/data/subvol-119-disk-0  usedbydataset         108G                      -
rpool/data/subvol-119-disk-0  usedbychildren        0B                        -
rpool/data/subvol-119-disk-0  usedbyrefreservation  0B                        -
rpool/data/subvol-119-disk-0  logbias               throughput                inherited from rpool
rpool/data/subvol-119-disk-0  objsetid              150727                    -
rpool/data/subvol-119-disk-0  dedup                 off                       inherited from rpool
rpool/data/subvol-119-disk-0  mlslabel              none                      default
rpool/data/subvol-119-disk-0  sync                  disabled                  inherited from rpool/data
rpool/data/subvol-119-disk-0  dnodesize             legacy                    default
rpool/data/subvol-119-disk-0  refcompressratio      1.33x                     -
rpool/data/subvol-119-disk-0  written               18.4G                     -
rpool/data/subvol-119-disk-0  logicalused           168G                      -
rpool/data/subvol-119-disk-0  logicalreferenced     136G                      -
rpool/data/subvol-119-disk-0  volmode               default                   default
rpool/data/subvol-119-disk-0  filesystem_limit      none                      default
rpool/data/subvol-119-disk-0  snapshot_limit        none                      default
rpool/data/subvol-119-disk-0  filesystem_count      none                      default
rpool/data/subvol-119-disk-0  snapshot_count        none                      default
rpool/data/subvol-119-disk-0  snapdev               hidden                    default
rpool/data/subvol-119-disk-0  acltype               posix                     local
rpool/data/subvol-119-disk-0  context               none                      default
rpool/data/subvol-119-disk-0  fscontext             none                      default
rpool/data/subvol-119-disk-0  defcontext            none                      default
rpool/data/subvol-119-disk-0  rootcontext           none                      default
rpool/data/subvol-119-disk-0  relatime              on                        inherited from rpool
rpool/data/subvol-119-disk-0  redundant_metadata    all                       default
rpool/data/subvol-119-disk-0  overlay               on                        default
rpool/data/subvol-119-disk-0  encryption            off                       default
rpool/data/subvol-119-disk-0  keylocation           none                      default
rpool/data/subvol-119-disk-0  keyformat             none                      default
rpool/data/subvol-119-disk-0  pbkdf2iters           0                         default
rpool/data/subvol-119-disk-0  special_small_blocks  0                         default
rpool/data/subvol-119-disk-0  snapshots_changed     Mon Apr 14 11:35:27 2025  -
rpool/data/subvol-119-disk-0  prefetch              all                       default

[filip-paczynski]

perhaps there is a bookmark holding these snapshots:

cannot destroy snapshot rpool/data/subvol-119-disk-0@restic-20250406-030001: dataset is busy
cannot destroy snapshot rpool/data/subvol-119-disk-0@restic-20250409-030001: dataset is busy

[amotin]

@filip-paczynski Bookmarks exist explicitly to allow snapshot deletion.

@yusing But something is indeed holding it. Have you looked towards zfs holds ... ?

[yusing]

Yes, forgot to list it. If have looked into zfs hold on both snapshots and found out nothing was holding them.

Btw, I fixed it with a reboot.

[filip-paczynski]

@filip-paczynski Bookmarks exist explicitly to allow snapshot deletion.

@yusing But something is indeed holding it. Have you looked towards zfs holds ... ?

Yes, you're right, I was thinking about holds - run into something similar with zrepl.