# Pastebin PI9lt8ct
dch@continuity ~> sudo zfs rename zroot/jails/h2o zroot/jails/h2o.old
cannot unmount '/jails/h2o': pool or dataset is busy
dch@continuity ~> sudo fstat -v |grep h2o

unknown file type 6 for file 8 of pid 5506
unknown file type 6 for file 4 of pid 94085
unknown file type 6 for file 13 of pid 94085
unknown file type 6 for file 16 of pid 94085
unknown file type 6 for file 19 of pid 94085
unknown file type 6 for file 22 of pid 94085
unknown file type 6 for file 25 of pid 94085
unknown file type 6 for file 30 of pid 94085
unknown file type 6 for file 33 of pid 94085
unknown file type 6 for file 5 of pid 33415
unknown file type 6 for file 12 of pid 33415
unknown file type 6 for file 17 of pid 33415
unknown file type 15 for file 5 of pid 98953
unknown file type 15 for file 6 of pid 98953
unknown file type 6 for file 3 of pid 97187
unknown file type 6 for file 25 of pid 97187
unknown file type 6 for file 29 of pid 97187
unknown file type 6 for file 3 of pid 7232
unknown file type 6 for file 13 of pid 7232
unknown file type 15 for file 14 of pid 7232
unknown file type 6 for file 4 of pid 33126
unknown file type 6 for file 11 of pid 33126
unknown file type 6 for file 16 of pid 33126