On Tue 05-01-21 10:48:48, Shijie Luo wrote: > Hi! > > On 2021/1/5 0:04, Jan Kara wrote: > > > Consuming the reference here because we won't "set frozen = > > > SB_FREEZE_COMPLETE" in thaw_super_locked() now. > > > > > > If don't do that, we never have a chance to consume it, thaw_super_locked() > > > will directly return "-EINVAL". But I do > > > > > > agree that it's not a good idea to return 0. How about returning "-EINVAL or > > > -ENOTSUPP" ? > > > > > > And, If we keep "frozen = SB_FREEZE_COMPLETE" in freeze_super() here, it > > > will cause another problem, thaw_super_locked() > > > > > > will always release rwsems in my logic, but freeze_super() won't acquire the > > > rwsems when filesystem is read-only. > > I was thinking about this for a while. I think the best solution would be > > to track whether the fs was read only (and thus frozen without locking > > percpu semaphores) at the time of freezing. I'm attaching that patch. Does > > it fix your problem? > > > > Honza > > I tested your patch, and it can indeed fix this deadlock problem. Thanks for testing! I've sent the patch to Al for inclusion. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
