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authorPaul Clements <paul.clements@steeleye.com>2012-09-17 14:09:02 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-09-17 15:00:37 -0700
commitfded4e090c60100d709318896c79816d68d5b47d (patch)
tree889cd9547a487296b5354b1956e174b4750a2737
parente9b7d7c81d9bdb41a897a2983ae3386a5fd4a1e3 (diff)
downloadop-kernel-dev-fded4e090c60100d709318896c79816d68d5b47d.zip
op-kernel-dev-fded4e090c60100d709318896c79816d68d5b47d.tar.gz
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>
-rw-r--r--drivers/block/nbd.c9
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;
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