On Wed, 21 Jan 2015 19:16:04 +0100 "Michael Kerrisk (man-pages)" <mtk.manpages@xxxxxxxxx> wrote: > Hi Jeff, > > On 21 January 2015 at 18:47, Jeff Layton <jlayton@xxxxxxxxxxxxxxx> wrote: > > On Wed, 21 Jan 2015 18:44:41 +0100 > > "Michael Kerrisk (man-pages)" <mtk.manpages@xxxxxxxxx> wrote: > > > >> Hi Jeff, > >> > >> I was recently checking some details of the man page for OFD locks, > >> and realized that one paragraph is somewhat misleading: > >> > >> Open file description locks always conflict with traditional > >> record locks, even when they are acquired by the same process on > >> the same file descriptor. > >> > >> This doesn't capture the full story, as far as I can tell. In > >> particular if we have two processes that take locks on the same region > >> of a file as follows: > >> > >> F_OFD_SETLK F_RDLCK > >> and > >> F_SETLK F_RDLCK > >> > >> then those pair of locks are compatible. I assume that's expected > >> behavior, right? I've drafted the patch below for the man page. Seem > >> okay? > >> > >> Cheers, > >> > >> Michael > >> > >> diff --git a/man2/fcntl.2 b/man2/fcntl.2 > >> index 59f22ce..03c2ae8 100644 > >> --- a/man2/fcntl.2 > >> +++ b/man2/fcntl.2 > >> @@ -495,7 +495,10 @@ and are only automatically released on the last close > >> of the open file description, > >> instead of being released on any close of the file. > >> .PP > >> -Open file description locks always conflict with traditional record locks, > >> +Conflicting lock combinations > >> +(i.e., a read lock and a write lock or two write locks) > >> +where one lock is an open file description lock and the other > >> +is a traditional record lock conflict > >> even when they are acquired by the same process on the same file descriptor. > >> > >> Open file description locks placed via the same open file description > >> > >> > > > > Yes, that is expected behavior and your patch looks good to me. > > > > Acked-by: Jeff Layton <jlayton@xxxxxxxxxxxxxxx> > > Thanks for the fast response!! It's a shame not to see you around the > mailing lists no more (at least not the ones I frequent). > > Best regards, > > Michael > No problem. I'm still around, but have been working on some other things (not so closely tied to userland interfaces). :) -- Jeff Layton <jlayton@xxxxxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
