On Mon, Mar 20, 2023 at 10:14:29AM -0700, Linus Torvalds wrote: > On Mon, Mar 20, 2023 at 4:52 AM Christian Brauner <brauner@xxxxxxxxxx> wrote: > > > > So before we continue down that road should we maybe treat this as a > > chance to fix the old bug? Because this behavior of returning -ENOTDIR > > has existed ever since v5.7 now. Since that time we had three LTS > > releases all returning ENOTDIR even if the file was created. > > Ack. > > I think considering that the return value has been broken for so long, > I think we can pretty much assume that there are no actual users of > it, and we might as well clean up the semantics properly. If there are no users of this and we can clean up the semantics, is there a strong reason *not* to make `O_DIRECTORY | O_CREATE` actually create a directory and atomically return a file descriptor for that directory? That seems like genuinely useful behavior that we don't currently have a syscall for. I didn't see any suggestion in the thread for reasons why we can't or shouldn't do that. Would that break some existing software? It doesn't *sound* like it would. As far as I can tell, that *also* wouldn't cause a problem with O_TMPFILE, because older kernels will still fail as desired, and we wouldn't change the behavior of O_TMPFILE on new kernels (it'd still create a temporary file, not a directory). - Josh Triplett
