From e69b8d414f948c242ad9f3eb2b7e24fba783dbbd Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Mon, 19 Jan 2015 12:06:14 +0300 Subject: rbd: drop parent_ref in rbd_dev_unprobe() unconditionally This effectively reverts the last hunk of 392a9dad7e77 ("rbd: detect when clone image is flattened"). The problem with parent_overlap != 0 condition is that it's possible and completely valid to have an image with parent_overlap == 0 whose parent state needs to be cleaned up on unmap. The next commit, which drops the "clone image now standalone" logic, opens up another window of opportunity to hit this, but even without it # cat parent-ref.sh #!/bin/bash rbd create --image-format 2 --size 1 foo rbd snap create foo@snap rbd snap protect foo@snap rbd clone foo@snap bar rbd resize --allow-shrink --size 0 bar rbd resize --size 1 bar DEV=$(rbd map bar) rbd unmap $DEV leaves rbd_device/rbd_spec/etc and rbd_client along with ceph_client hanging around. My thinking behind calling rbd_dev_parent_put() unconditionally is that there shouldn't be any requests in flight at that point in time as we are deep into unmap sequence. Hence, even if rbd_dev_unparent() caused by flatten is delayed by in-flight requests, it will have finished by the time we reach rbd_dev_unprobe() caused by unmap, thus turning unconditional rbd_dev_parent_put() into a no-op. Fixes: http://tracker.ceph.com/issues/10352 Cc: stable@vger.kernel.org # 3.11+ Signed-off-by: Ilya Dryomov Reviewed-by: Josh Durgin Reviewed-by: Alex Elder --- drivers/block/rbd.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index d511ecb35144..8a86b62466f7 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -5106,10 +5106,7 @@ static void rbd_dev_unprobe(struct rbd_device *rbd_dev) { struct rbd_image_header *header; - /* Drop parent reference unless it's already been done (or none) */ - - if (rbd_dev->parent_overlap) - rbd_dev_parent_put(rbd_dev); + rbd_dev_parent_put(rbd_dev); /* Free dynamic fields from the header, then zero it out */ -- cgit v1.2.3