This patch adds I/O suspend / resume functionality to blktap. When suspending ... I/O requests and ignored inflight I/Os are completed (up to the 5 min timeout) the suspend() call is synchronous (with a 5 min timeout) tapdisk associated with the vdisk is shot down (SIGHUP) internal I/O "scheduler" thread is cancelled When resuming ... blktap is directed to process I/O requests once again. tapdisk is resurected via blktapcntrl and a xenstore watch internal I/O "scheduler" thread is created Signed-off-by: Ben Guthro Signed-off-by: Josh Nicholas