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rbd: move rbd_unregister_watch() call into rbd_dev_image_release() 

rbd_dev->disk tear down vs rbd_watch_cb() race shouldn't be a problem
anymore thanks to EXISTS and REMOVING checks in rbd_dev_update_size().
A similar race could occur on "rbd map", see commit 811c668877
("rbd: fix rbd map vs notify races").

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>
This commit is contained in:
Ilya Dryomov 2017-04-13 12:17:37 +02:00
parent 8b679ec525
commit fd22aef8b4
1 changed files with 3 additions and 15 deletions
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18
drivers/block/rbd.c
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@ -5964,6 +5964,8 @@ static int rbd_dev_header_name(struct rbd_device *rbd_dev)
static void rbd_dev_image_release(struct rbd_device *rbd_dev)
{
rbd_dev_unprobe(rbd_dev);
if (rbd_dev->opts)
rbd_unregister_watch(rbd_dev);
rbd_dev->image_format = 0;
kfree(rbd_dev->spec->image_id);
rbd_dev->spec->image_id = NULL;
@ -6126,15 +6128,8 @@ static ssize_t do_rbd_add(struct bus_type *bus,
rbd_dev->mapping.read_only = read_only;
rc = rbd_dev_device_setup(rbd_dev);
if (rc) {
/*
* rbd_unregister_watch() can't be moved into
* rbd_dev_image_release() without refactoring, see
* commit 1f3ef78861ac.
*/
rbd_unregister_watch(rbd_dev);
if (rc)
goto err_out_image_probe;
}
rc = count;
out:
@ -6275,14 +6270,7 @@ static ssize_t do_rbd_remove(struct bus_type *bus,
if (__rbd_is_lock_owner(rbd_dev))
rbd_unlock(rbd_dev);
up_write(&rbd_dev->lock_rwsem);
rbd_unregister_watch(rbd_dev);
/*
* Don't free anything from rbd_dev->disk until after all
* notifies are completely processed. Otherwise
* rbd_bus_del_dev() will race with rbd_watch_cb(), resulting
* in a potential use after free of rbd_dev->disk or rbd_dev.
*/
rbd_dev_device_release(rbd_dev);
rbd_dev_image_release(rbd_dev);
rbd_dev_destroy(rbd_dev);