Re: dirty balancing deadlock

[Miklos Szeredi <miklos@szeredi.hu>]

> > > In general, writepage is supposed to do work without blocking on
> > > expensive locks that will get pdflush and dirty reclaim stuck in this
> > > fashion.  You'll probably have to take the same approach reiserfs does
> > > in data=journal mode, which is leaving the page dirty if fuse_get_req_wp
> > > is going to block without making progress.
> > 
> > Pdflush, and dirty reclaim set wbc->nonblocking to true.
> > balance_dirty_pages and fsync don't.  The problem here is that
> > Andrew's patch is wrong to let balance_dirty_pages() try to write back
> > pages from a different queue.
> 
> async or sync, writepage is supposed to either make progress or bail.
> loopback aside, if the fuse call is blocking long term, you're going to
> run into problems.

Hmm, like what?

Thanks,
Miklos