Make removing disk devices with mounted filesystems on them safe.

FreeBSD Developer: Edward Tomasz Napierala

The project is to make FreeBSD tolerate the removal of active disk devices, such as when a USB flash device with a mounted filesystems is physically detached by a user. Currently the system may panic in this situation. The work involves adding proper reference counting to strategic portions of the kernel and modifying filesystems to properly handle “device lost” errors.

This project was completed in 2009.