Messages in this thread | | | Date | Tue, 24 Jan 2012 07:53:09 -0800 | From | Tejun Heo <> | Subject | Re: [PATCH 14/16] blkcg: don't allow or retain configuration of missing devices |
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On Tue, Jan 24, 2012 at 10:42:24AM -0500, Vivek Goyal wrote: > On Mon, Jan 23, 2012 at 03:09:51PM -0800, Tejun Heo wrote: > > + disk = get_gendisk(dev, &part); > > + > > + if ((!disk || part) && temp) { > > + ret = -ENODEV; > > + goto out; > > + } > > + > > + rcu_read_lock(); > > + > > + if (disk && !part) { > > + spin_lock_irq(disk->queue->queue_lock); > > + blkg = blkg_lookup_create(blkcg, disk->queue, plid); > > + spin_unlock_irq(disk->queue->queue_lock); > > If queue is in bypass mode, is group creation and linking allowed when > somebody is trying to set per device rules. (/me is thinking if there are > any potential races between elevator switch and rule setting in cgroup).
Yeap, there is. Nice catch. blkg_lookup_create() should be testing blk_queue_bypass() instead of blk_queue_dead() and parse_and_set should probably retry after a bit. Will update.
Thanks.
-- tejun
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