On Mon, Aug 11, 2014 at 10:51:47AM +0200, Jan Kara wrote: > So I'm afraid we'll have to find some other way to synchronize > page faults and truncate / punch hole in DAX. What if we don't? If we hit the race (which is vanishingly unlikely with real applications), the consequence is simply that after a truncate, a file may be left with one or two blocks allocated somewhere after i_size. As I understand it, that's not a real problem; they're temporarily unavailable for allocation but will be freed on file removal or the next truncation of that file. I'm also still considering the possibility of having truncate-down block until all mmaps that extend after the new i_size have been removed ... -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>