[Drbd-dev] [PATCH] Proposed fix to 8.0.x to ALWAYS scheduleafterstate processing

[Graham, Simon]

> >
> > We have found one issue with this patch -- we are now seeing
> occasional
> > messages:
> >
> > BUG! md_sync_timer expired! Worker calls drbd_md_sync()
> 
> the "BUG!" already got remove out of that message, it is no bug,
> but only some sloppy timing of certain things on our part.
> 
> > I _think_ this is because the meta data can be marked dirty in the
> after
> > state change processing and we now have some situations where this
> > happens after the code runs that writes the meta data -- I'm not
sure
> > how terrible it is, but I think we should move the code that marks
> the
> > meta data dirty into _drbd_set_state() so it happens inline -- I
> don't
> > see any reason why it has to be done in the worker thread... what do
> you
> > think?
> 
> my design proposal was to set the meta-data dirty flag _implicitly_,
> once something is changed that should be recorded on disk.  this
> "dirtying" would also schedule the timer to alert us of code pathes
> that
> take too long to actually get these changes on disk.  unfortunately we
> never got around to implementing the "implicit" part of it.
> 
> yes, this "dirtying" should happen as early as possible.
> 

I made the proposed change and also fixed one other small bugette in my
original patch that caused a device that went to the PausedSync state
initially to actually go ahead and sync anyway! Attached is the final
patch for the proposed changes to ALWAYS schedule after state change
processing.

Simon
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