On Fri, Oct 20, 2017 at 10:27:22AM -0700, Dan Williams wrote: > I'll take a look at hooking this up through a page-idle callback. Can > I get some breadcrumbs to grep for from XFS folks on how to set/clear > the busy state of extents?
As Brian pointed out it's the xfs_extent_busy.c file (and I pointed out the same in a reply to the previous series). Be careful because you'll need a refcount or flags now that there are different busy reasons. I still think we'd be better off just blocking on an elevated page count directly in truncate as that will avoid all the busy list manipulations.