On Fri, Jun 3, 2016 at 8:49 PM, Maxim Patlasov <mpatlasov@xxxxxxxxxxxxx> wrote: > Hi Miklos, > > fuse_file_lock() since its inception in 2006 implements F_SETLK command like > this: > >> if (fc->no_lock) >> err = posix_lock_file(file, fl, NULL); >> else >> err = fuse_setlk(file, fl, 0); > > > where fc->no_lock is a per-mount-point tunable. It would be more natural to > posix-lock in both cases, like this: > >> err = posix_lock_file(file, fl, NULL); >> if (!err && !fc->no_lock) >> err = fuse_setlk(file, fl, 0); > > > Otherwise, by default, when fc->no_lock=0, posix_lock_file() is never > called, and from end-user perspective it is weird that the file was locked > successfully, but "fdinfo" does not show the lock. > > Do you think there were some reasons to implement it that way -- not calling > posix_lock_file unconditionally? Calling posix_lock_file() *before* we know the file can actually be locked may be setting us up for weird bugs. It could be called afterwards, when we already know the real locking operation succeeded. But we need to think very carefully about races between two locking operations, because locking state update is non-atomic after that change. So I think this possibly can be done, but needs some thought. Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
