On Tue, Jan 21, 2025 at 01:07:38PM +0100, Miklos Szeredi wrote: > On Sun, 19 Jan 2025 at 06:40, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > > Miklos, could you recall what was the original intent of that? > > Do we want to keep that logics there, or should it just turn into > > "map -ENOPENSTALE to -ESTALE?? > > I think the intent was to prevent a full LOOKUP_REVAL if this happened > on the first try in do_filp_open(). I still think that makes sense, > but needs a comment since it's not obvious. For that to have happened we need the following sequence: * we started in RCU mode * we'd run into something that needs fallback to non-RCU (e.g. open() callback itself) * we had successfully switched to non-lazy mode - grabbed references, etc. * we got to call of open() callback and that returned us -EOPENSTALE. What's the point of re-walking the same trajectory in dcache again and why would it yield something different this time around? IDGI. We *can't* get to open callback without having already dealt with leaving RCU mode - any chance of having walked into the wrong place due to lack of locking has already been excluded when we'd successfully left RCU mode; otherwise we would've gotten to that check with error already equal to -ECHILD. What sequence of events do you have in mind?
