nbd: ratelimit error msgs after socket close

Make the "Attempted send on closed socket" error messages generated in
nbd_request_handler() ratelimited.

When the nbd socket is shutdown, the nbd_request_handler() function emits
an error message for every request remaining in its queue.  If the queue
is large, this will spam a large amount of messages to the log.  There's
no need for a separate error message for each request, so this patch
ratelimits it.

In the specific case this was found, the system was virtual and the error
messages were logged to the serial port, which overwhelmed it.

Fixes: 4d48a542b427 ("nbd: fix I/O hang on disconnected nbds")
Signed-off-by: Dan Streetman <dan.streetman@canonical.com>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index b67500d5b338a16ad727217bfb7911d9b71fb26b..4c5d94146aa3b2ca568f3b630ef5b93a1586a6f1 100644 (file)
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -580,8 +580,8 @@ static void nbd_request_handler(struct request_queue *q)
                        req, req->cmd_type);
 
                if (unlikely(!nbd->sock)) {
-                       dev_err(disk_to_dev(nbd->disk),
-                               "Attempted send on closed socket\n");
+                       dev_err_ratelimited(disk_to_dev(nbd->disk),
+                                           "Attempted send on closed socket\n");
                        req->errors++;
                        nbd_end_request(nbd, req);
                        spin_lock_irq(q->queue_lock);