Dropping the queue_lock opens up a nasty race, fix this race by
plugging the device when we're done.
Also includes a small cleanup.
Signed-off-by: Peter Zijlstra <[EMAIL PROTECTED]>
CC: Pavel Machek <[EMAIL PROTECTED]>
---
drivers/block/nbd.c | 67 ++++++++++++++++++++++++++++++++++++++--------------
1 file changed, 49 insertions(+), 18 deletions(-)
Index: linux-2.6/drivers/block/nbd.c
===================================================================
--- linux-2.6.orig/drivers/block/nbd.c 2006-09-07 17:20:52.000000000 +0200
+++ linux-2.6/drivers/block/nbd.c 2006-09-07 17:35:05.000000000 +0200
@@ -97,20 +97,24 @@ static const char *nbdcmd_to_ascii(int c
}
#endif /* NDEBUG */
-static void nbd_end_request(struct request *req)
+static void __nbd_end_request(struct request *req)
{
int uptodate = (req->errors == 0) ? 1 : 0;
- request_queue_t *q = req->q;
- unsigned long flags;
dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name,
req, uptodate? "done": "failed");
- spin_lock_irqsave(q->queue_lock, flags);
- if (!end_that_request_first(req, uptodate, req->nr_sectors)) {
+ if (!end_that_request_first(req, uptodate, req->nr_sectors))
end_that_request_last(req, uptodate);
- }
- spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+static void nbd_end_request(struct request *req)
+{
+ request_queue_t *q = req->q;
+
+ spin_lock_irq(q->queue_lock);
+ __nbd_end_request(req);
+ spin_unlock_irq(q->queue_lock);
}
/*
@@ -435,10 +439,8 @@ static void do_nbd_request(request_queue
mutex_unlock(&lo->tx_lock);
printk(KERN_ERR "%s: Attempted send on closed socket\n",
lo->disk->disk_name);
- req->errors++;
- nbd_end_request(req);
spin_lock_irq(q->queue_lock);
- continue;
+ goto error_out;
}
lo->active_req = req;
@@ -463,10 +465,13 @@ static void do_nbd_request(request_queue
error_out:
req->errors++;
- spin_unlock(q->queue_lock);
- nbd_end_request(req);
- spin_lock(q->queue_lock);
+ __nbd_end_request(req);
}
+ /*
+ * q->queue_lock has been dropped, this opens up a race
+ * plug the device to close it.
+ */
+ blk_plug_device(q);
return;
}
--
-
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