> > > This allows the direct I/O path to do I/O and raise & lower page->_refcount > > > while we're executing a truncate/hole punch. This leads to us trying to free > > > a page with an elevated refcount. > > I don't see how this is possible in XFS - maybe I'm missing > something, but "direct IO submission during truncate" is not > something that should ever be happening in XFS, DAX or not. The pages involved in a direct I/O are not that of the file that the direct I/O read/write syscalls are called on, but those of the memory regions the direct I/O read/write syscalls operate on. Those pages could be file backed and undergo a truncate at the same time.
