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Commit 82a442d2 authored by Alex Elder's avatar Alex Elder Committed by Sage Weil
Browse files

rbd: protect against concurrent unmaps 



Make sure two concurrent unmap operations on the same rbd device
won't collide, by only proceeding with the removal and cleanup of a
device if is not already underway.

Signed-off-by: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarJosh Durgin <josh.durgin@inktank.com>
parent 751cc0e3

drivers/block/rbd.c

+4 −2
Original line number Diff line number Diff line
@@ -5137,6 +5137,7 @@ static ssize_t rbd_remove(struct bus_type *bus, 
	struct list_head *tmp;

	int dev_id;

	unsigned long ul;

	bool already = false;

	int ret;



	ret = strict_strtoul(buf, 10, &ul);
@@ -5164,11 +5165,12 @@ static ssize_t rbd_remove(struct bus_type *bus, 
		if (rbd_dev->open_count)

			ret = -EBUSY;

		else

			set_bit(RBD_DEV_FLAG_REMOVING, &rbd_dev->flags);

			already = test_and_set_bit(RBD_DEV_FLAG_REMOVING,

							&rbd_dev->flags);

		spin_unlock_irq(&rbd_dev->lock);

	}

	spin_unlock(&rbd_dev_list_lock);

	if (ret < 0)

	if (ret < 0 || already)

		goto done;



	rbd_bus_del_dev(rbd_dev);