nachtrag:
grep rpool/subvol-135-disk-0 /proc/*/mounts
/proc/102150/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/103362/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/103452/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/103457/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/103463/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/103465/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/103467/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/1034/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/1037/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/1040/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/104422/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/104911/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/105099/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/105103/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/105114/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/105619/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/105733/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/1057/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/1058/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/107634/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/107643/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/107644/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/107651/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/107675/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/108278/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/108281/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/108283/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/108288/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/108291/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
grep: /proc/108420/mounts: Das Argument ist ungültig
/proc/115795/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/115810/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/115815/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/115818/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/115820/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/116698/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
grep: /proc/116764/mounts: Das Argument ist ungültig
/proc/117758/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/119570/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/119581/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/119588/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/119594/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/119598/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/120630/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/124129/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/124135/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/124139/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/124142/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/124145/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/125979/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/125985/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/125988/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/125991/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/125993/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/126236/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/126238/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/126240/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/126241/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/126371/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/127417/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/14572/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/21843/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/21845/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/21851/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/21855/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/21856/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/25699/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/25704/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/25707/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/25709/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/25710/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/28181/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/29542/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/30396/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
grep: /proc/3257/mounts: Das Argument ist ungültig
/proc/32839/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/34240/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/36495/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
grep: /proc/39106/mounts: Das Argument ist ungültig
/proc/42069/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/42073/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/42080/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/42090/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/42093/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/43308/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/43317/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/43323/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/43326/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/43327/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/4350/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/47177/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/47182/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/47184/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/47188/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/47191/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
grep: /proc/5227/mounts: Das Argument ist ungültig
/proc/53711/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/53713/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/53719/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/53726/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/54285/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
grep: /proc/54721/mounts: Das Argument ist ungültig
/proc/57759/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/57764/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/57772/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/57833/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/57871/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/58609/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/64375/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
grep: /proc/64944/mounts: Das Argument ist ungültig
/proc/66094/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/66098/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/66103/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/66115/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/66116/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/67417/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/67780/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/67845/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/67847/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/67848/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/68148/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/68159/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/68163/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/68170/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/68177/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/71742/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/72031/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/72884/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/77704/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/77716/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/77724/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/77727/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/77734/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/77784/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/77790/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/77796/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/77802/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/77806/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/81890/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/81892/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/85563/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/90883/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/91656/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/94172/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/94175/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/94179/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/94181/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/94183/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/94441/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/94443/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/94447/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0
/proc/94449/mounts:rpool/subvol-135-disk-0 / zfs rw,noatime,xattr,posixacl 0 0