commit: fded4e090c60100d709318896c79816d68d5b47d From: Paul Clements <[email protected]> Date: Mon, 17 Sep 2012 14:09:02 -0700 Subject: 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 <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> --- drivers/block/nbd.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index d07c9f7..0c03411 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -449,6 +449,14 @@ static void nbd_clear_que(struct nbd_device *nbd) req->errors++; nbd_end_request(req); } + + while (!list_empty(&nbd->waiting_queue)) { + req = list_entry(nbd->waiting_queue.next, struct request, + queuelist); + list_del_init(&req->queuelist); + req->errors++; + nbd_end_request(req); + } } @@ -598,6 +606,7 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, nbd->file = NULL; nbd_clear_que(nbd); BUG_ON(!list_empty(&nbd->queue_head)); + BUG_ON(!list_empty(&nbd->waiting_queue)); if (file) fput(file); return 0; -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
