On Wed, Jun 08, 2016 at 07:30:55AM +0300, Konstantin Belousov wrote: > On Tue, Jun 07, 2016 at 11:19:19PM +0200, Jilles Tjoelker wrote: > > In this case it is clear which sleep(9) calls should be affected so it > > may be better to avoid more hidden state. > In this case yes, but apparently some out-of-tree users exist. And, > the marking of the single sx_sleep() call depends on knowing our > implementation. I remember that as the arguments to change from PBDRY to > the current state setter, in NFS it is not too hard to try to enumerate > interruptible sleeps. > > > > > I also wonder whether we may be overengineering things here. Perhaps > > the advlock sleep can simply turn off TDF_SBDRY. > Well, this was the very first patch suggested. I would be fine with that, > but again, out-of-tree code seems to be not quite fine with that local > solution.
In our particular case, we could possibly use a similar approach. In general, it seems incorrect to clear TDF_SBDRY if the thread calling sx_sleep() has any locks held. It is easy to verify that all callers of lf_advlock() are safe in this respect, but this kind of auditing is generally hard. In fact, I believe the sx_sleep that led to the problem described in D2612 is the same as the one in my case. That is, the sleeping thread may or may not hold a vnode lock depending on context. _______________________________________________ email@example.com mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"