Pushing to docker registry fails: Error mounting /dev/mapper/...: device or resource busy -

i'm trying push docker image own registry server, fail on lxc-docker 1.7.1, ubuntu 14.04, linux kernel 3.17.1-vanilla-3.17-for-dp-mst:

the push refers repository [example.org:5001/example/name] (len: 1) 45615d5b6520: image exists  d660ae18c164: image exists  ce175a447fba: image exists  3bfbc78d8ab0: image exists  ff51cac082ac: buffering disk  error pushing registry: error mounting  '/dev/mapper/docker-252:1-2885400-d3010c1febd33ebba400a593df550db2064cf16541d3970fb93bb524ee6056b4'  on '/var/lib/docker/devicemapper/mnt/d3010c1febd33ebba400a593df550db2064cf16541d3970fb93bb524ee6056b4':  device or resource busy 

what can fix this?

restarting docker daemon did not help. had set --storage-opt='dm.blocksize=64k' docker daemon start option; otherwise not start @ all.

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this sounds bit "device or resource busy" error when trying push image docker, error generating layered archive.

rebooting new kernel (3.19.0-22) , matching -extras package made work.