On Tue, 8 Nov 2011, Noah Watkins wrote: > ----- Original Message ----- > > From: "Tommi Virtanen" <tommi.virtanen@xxxxxxxxxxxxx> > > > > The value in returning the number that *would have been written* is in > > that now the caller can reallocate a buffer of exactly the right size > > (barring races). Like snprintf() and friends. With just a generic > > -ENOBUFS/-EMSGSIZE/whatever you cram in there, the caller must do a > > series of increasing guesses. > > > > Thanks for the feedback. I ended up using -ERANGE, and allow naddr=0 for > querying the actual size. The only issue with this is that, in the event that you don't guess a sufficiently large array on the first call, you may need to call again, and in some cases that may mean multiple MDS requests. Normally that's not the case. And a smart caller should guess 4 and only pass 0 and then N if 4 failed. But a naive caller will always make two calls, first with 0 and then with N, and in some cases that's actually slower. Does it matter? sage -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
