nbd: don't requeue the same request twice.
[ Upstream commit d7d94d48a2
]
We can race with the snd timeout and the per-request timeout and end up
requeuing the same request twice. We can't use the send_complete
completion to tell if everything is ok because we hold the tx_lock
during send, so the timeout stuff will block waiting to mark the socket
dead, and we could be marked complete and still requeue. Instead add a
flag to the socket so we know whether we've been requeued yet.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
parent
962ff36dac
commit
ced413c5ef
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@ -112,12 +112,15 @@ struct nbd_device {
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struct task_struct *task_setup;
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};
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#define NBD_CMD_REQUEUED 1
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struct nbd_cmd {
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struct nbd_device *nbd;
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int index;
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int cookie;
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struct completion send_complete;
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blk_status_t status;
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unsigned long flags;
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};
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#if IS_ENABLED(CONFIG_DEBUG_FS)
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@ -146,6 +149,14 @@ static inline struct device *nbd_to_dev(struct nbd_device *nbd)
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return disk_to_dev(nbd->disk);
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}
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static void nbd_requeue_cmd(struct nbd_cmd *cmd)
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{
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struct request *req = blk_mq_rq_from_pdu(cmd);
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if (!test_and_set_bit(NBD_CMD_REQUEUED, &cmd->flags))
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blk_mq_requeue_request(req, true);
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}
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static const char *nbdcmd_to_ascii(int cmd)
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{
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switch (cmd) {
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@ -328,7 +339,7 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
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nbd_mark_nsock_dead(nbd, nsock, 1);
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mutex_unlock(&nsock->tx_lock);
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}
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blk_mq_requeue_request(req, true);
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nbd_requeue_cmd(cmd);
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nbd_config_put(nbd);
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return BLK_EH_NOT_HANDLED;
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}
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@ -484,6 +495,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
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nsock->pending = req;
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nsock->sent = sent;
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}
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set_bit(NBD_CMD_REQUEUED, &cmd->flags);
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return BLK_STS_RESOURCE;
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}
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dev_err_ratelimited(disk_to_dev(nbd->disk),
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@ -525,6 +537,7 @@ send_pages:
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*/
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nsock->pending = req;
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nsock->sent = sent;
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set_bit(NBD_CMD_REQUEUED, &cmd->flags);
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return BLK_STS_RESOURCE;
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}
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dev_err(disk_to_dev(nbd->disk),
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@ -793,7 +806,7 @@ again:
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*/
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blk_mq_start_request(req);
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if (unlikely(nsock->pending && nsock->pending != req)) {
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blk_mq_requeue_request(req, true);
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nbd_requeue_cmd(cmd);
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ret = 0;
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goto out;
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}
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@ -806,7 +819,7 @@ again:
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dev_err_ratelimited(disk_to_dev(nbd->disk),
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"Request send failed, requeueing\n");
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nbd_mark_nsock_dead(nbd, nsock, 1);
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blk_mq_requeue_request(req, true);
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nbd_requeue_cmd(cmd);
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ret = 0;
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}
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out:
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@ -831,6 +844,7 @@ static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
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* done sending everything over the wire.
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*/
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init_completion(&cmd->send_complete);
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clear_bit(NBD_CMD_REQUEUED, &cmd->flags);
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/* We can be called directly from the user space process, which means we
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* could possibly have signals pending so our sendmsg will fail. In
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@ -1446,6 +1460,7 @@ static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
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{
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struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
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cmd->nbd = set->driver_data;
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cmd->flags = 0;
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return 0;
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}
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