root@stor6:~# ceph-objectstore-tool --debug --op export --pgid 1.60 --data-path /var/lib/ceph/osd/ceph-84 --journal-path /var/lib/ceph/osd/ceph-84/journal --file /var/lib/ceph/osd/ceph-83/backup/1.60.export
2017-05-24 23:28:58.540842 7f500948e940  0 filestore(/var/lib/ceph/osd/ceph-84) backend btrfs (magic 0x9123683e)
2017-05-24 23:28:58.541228 7f500948e940  0 genericfilestorebackend(/var/lib/ceph/osd/ceph-84) detect_features: FIEMAP ioctl is supported and appears to work
2017-05-24 23:28:58.541236 7f500948e940  0 genericfilestorebackend(/var/lib/ceph/osd/ceph-84) detect_features: SEEK_DATA/SEEK_HOLE is disabled via 'filestore seek data hole' config option
2017-05-24 23:28:58.541249 7f500948e940  0 genericfilestorebackend(/var/lib/ceph/osd/ceph-84) detect_features: splice is supported
2017-05-24 23:28:58.543398 7f500948e940  0 genericfilestorebackend(/var/lib/ceph/osd/ceph-84) detect_features: syncfs(2) syscall fully supported (by glibc and kernel)
2017-05-24 23:28:58.543447 7f500948e940  0 btrfsfilestorebackend(/var/lib/ceph/osd/ceph-84) detect_feature: CLONE_RANGE ioctl is supported
2017-05-24 23:28:58.543465 7f500948e940  0 btrfsfilestorebackend(/var/lib/ceph/osd/ceph-84) detect_feature: failed to create simple subvolume test_subvol: (17) File exists
2017-05-24 23:28:58.543481 7f500948e940  0 btrfsfilestorebackend(/var/lib/ceph/osd/ceph-84) detect_feature: SNAP_CREATE is supported
2017-05-24 23:28:58.543994 7f500948e940  0 btrfsfilestorebackend(/var/lib/ceph/osd/ceph-84) detect_feature: SNAP_DESTROY is supported
2017-05-24 23:28:58.544120 7f500948e940  0 btrfsfilestorebackend(/var/lib/ceph/osd/ceph-84) detect_feature: START_SYNC is supported (transid 453357)
2017-05-24 23:28:58.545769 7f500948e940  0 btrfsfilestorebackend(/var/lib/ceph/osd/ceph-84) detect_feature: WAIT_SYNC is supported
2017-05-24 23:28:58.545786 7f500948e940  0 btrfsfilestorebackend(/var/lib/ceph/osd/ceph-84) detect_feature: removing old async_snap_test
2017-05-24 23:28:58.547106 7f500948e940  0 btrfsfilestorebackend(/var/lib/ceph/osd/ceph-84) detect_feature: SNAP_CREATE_V2 is supported
2017-05-24 23:28:58.547456 7f500948e940 -1 filestore(/var/lib/ceph/osd/ceph-84) ERROR: /var/lib/ceph/osd/ceph-84/current/nosnap exists, not rolling back to avoid losing new data
Mount failed with '(95) Operation not supported'
2017-05-24 23:28:58.547462 7f500948e940 -1 filestore(/var/lib/ceph/osd/ceph-84) Force rollback to old snapshotted version with 'osd use stale snap = true'
2017-05-24 23:28:58.547463 7f500948e940 -1 filestore(/var/lib/ceph/osd/ceph-84) config option for --osd-use-stale-snap startup argument.