On Thu, Jan 27, 2022 at 01:38:58PM +1100, Daniel Black wrote: > > Sorry for the confusion. You've caught us mid-transition. Eventually, > > ->direct_IO will be deleted, but for now it signifies whether or not the > > filesystem supports O_DIRECT, even though it's not used (except in some > > scenarios you don't care about). > > being executed at the bottom of setfl which keeps the file descriptor > out of O_DIRECT mode when > the filesystem (like CIFS doesn't support it). In the original strace Apparently I wasn't clear ... CIFS absolutely does support O_DIRECT. It does not do it by calling ->direct_IO; instead it's handled in cifs_loose_read_iter().
