| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.10 096/129] rbd: protect against concurrent unmaps | Date | Mon, 6 Jan 2014 14:38:45 -0800 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Alex Elder <elder@inktank.com>
commit 82a442d239695a242c4d584464c9606322cd02aa upstream.
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: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/block/rbd.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -5108,6 +5108,7 @@ static ssize_t rbd_remove(struct bus_typ struct list_head *tmp; int dev_id; unsigned long ul; + bool already = false; int ret; ret = strict_strtoul(buf, 10, &ul); @@ -5135,11 +5136,12 @@ static ssize_t rbd_remove(struct bus_typ 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);
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