Unable to destroy snapshot while rollbacking...

Steps as follows :

[root@localhost kqinfo]# zpool create tank /dev/sdb1

[root@localhost kqinfo]# zfs create tank/zfs

[root@localhost kqinfo]# cd /tank/

[root@localhost tank]# touch a

[root@localhost tank]# touch b

[root@localhost tank]# cd zfs/

[root@localhost zfs]# touch f

[root@localhost zfs]# touch k

[root@localhost zfs]# cd .. [root@localhost tank]# cd ..

[root@localhost /]# zfs snapshot tank@snap1

[root@localhost /]# zfs snapshot tank@snap2

[root@localhost /]# zfs snapshot tank@snap3

[root@localhost /]# zfs snapshot tank@snap4

[root@localhost /]# zfs snapshot tank@snap5

[root@localhost /]# zfs snapshot tank@snap6

[root@localhost /]# zfs rollback -r tank@snap2

[root@localhost /]# cd /tank/.zfs/snapshot/snap

snap1/ snap2/

[root@localhost /]# cd /tank/.zfs/snapshot/snap

[root@localhost /]# zfs snapshot tank/zfs@snap11

[root@localhost /]# zfs snapshot tank/zfs@snap12

[root@localhost /]# zfs snapshot tank/zfs@snap13

[root@localhost /]# zfs snapshot tank/zfs@snap14

[root@localhost /]# zfs snapshot tank/zfs@snap15

[root@localhost /]# zfs snapshot tank/zfs@snap16

[root@localhost /]# zfs rollback -r tank/zfs@snap12

[root@localhost /]# cd /tank/zfs/.zfs/snapshot/snap1 snap11/ snap12/

[root@localhost /]# cd /tank/zfs/.zfs/snapshot/snap1

[root@localhost /]# zfs snapshot tank/zfs@snap17

[root@localhost /]# zfs snapshot tank/zfs@snap18

[root@localhost /]# zfs snapshot tank/zfs@snap19

[root@localhost /]# zfs snapshot tank@snap20

[root@localhost /]# zfs snapshot tank@snap21

[root@localhost /]# cd /tank/.zfs/snapshot/snap snap1/ snap2/ snap20/ snap21/

[root@localhost /]# cd /tank/zfs/.zfs/snapshot/snap1 snap11/ snap12/ snap17/ snap18/ snap19/

[root@localhost /]# zfs rollback -r tank/zfs@snap17

cannot destroy 'tank/zfs@snap19': dataset is busy cannot destroy 'tank/zfs@snap18': dataset is busy

[root@localhost /]#

zfs-linux / zfs