On Tue, Jun 08, 2010 at 06:47:18PM +1000, Dave Chinner wrote: > On Tue, Jun 08, 2010 at 09:15:35AM +0200, Christof Schmitt wrote: > > > But my original changes were along the lines of what Jan mentioned > > > earlier (hooking into page_mkwrite and waiting for writeback. I could > > > have sworn that I only did it for ext[23] and that XFS waited out of the > > > box but git proves me wrong). Anyway, I'll try to get some benchmarking > > > happening later this week. > > > > Is there a patch with this change available somewhere? It might be > > useful to patch a kernel with this XFS change for reliable DIF/DIX > > testing. > > Adding a wait_on_page_writeback() call to page_mkwrite() won't help > by itself - you need to unmap the pages after transitioning them > from dirty to writeback but before the hardware starts processing > the IO if you want to lock out mmap writes this way.... Actually as Jan pointed out, clear_page_dirty_for_io already does this. So it seems pretty doable. get_user_pages remains a problem (which I believe NFS just ignores) but it could be avoided by just disallowing it. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
