Re: [patch] vmfixes-2.4.0-test9-B2 - fixing deadlocks

Alexander Viro
2000-09-25T16:06:41Z

On Mon, 25 Sep 2000, Ingo Molnar wrote:

>
> On Mon, 25 Sep 2000, Stephen C. Tweedie wrote:
>
> > Sorry, but in this case you have got a lot more variables than you
> > seem to think. The obvious lock is the ext2 superblock lock, but
> > there are side cases with quota and O_SYNC which are much less
> > commonly triggered. That's not even starting to consider the other
> > dozens of filesystems in the kernel which have to be audited if we
> > change the locking requirements for GFP calls.
>
> i'd suggest to simply BUG() in schedule() if the superblock lock is held
> not directly by lock_super. Holding the superblock lock is IMO quite rude
> anyway (for performance and latency) - is there any place where we hold it
> for a long time and it's unavoidable?

Ingo, schedule() has no bloody business _knowing_ about superblock locks
in the first place. Yes, ext2 should not bother taking it at all. For
completely unrelated reasons.