tree 889cd9547a487296b5354b1956e174b4750a2737
parent e9b7d7c81d9bdb41a897a2983ae3386a5fd4a1e3
author Paul Clements <paul.clements@steeleye.com> 1347916142 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1347919237 -0700

nbd: clear waiting_queue on shutdown

Fix a serious but uncommon bug in nbd which occurs when there is heavy
I/O going to the nbd device while, at the same time, a failure (server,
network) or manual disconnect of the nbd connection occurs.

There is a small window between the time that the nbd_thread is stopped
and the socket is shutdown where requests can continue to be queued to
nbd's internal waiting_queue.  When this happens, those requests are
never completed or freed.

The fix is to clear the waiting_queue on shutdown of the nbd device, in
the same way that the nbd request queue (queue_head) is already being
cleared.

Signed-off-by: Paul Clements <paul.clements@steeleye.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>