From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: [RFC] readdir mess Date: Tue, 12 Aug 2008 13:21:56 -0700 (PDT) Message-ID: References: <20080812062241.GQ28946@ZenIV.linux.org.uk> <87ej4u9nf5.fsf@devron.myhome.or.jp> <20080812181057.GR28946@ZenIV.linux.org.uk> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: OGAWA Hirofumi , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: Al Viro Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:42620 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750857AbYHLUWA (ORCPT ); Tue, 12 Aug 2008 16:22:00 -0400 In-Reply-To: <20080812181057.GR28946@ZenIV.linux.org.uk> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, 12 Aug 2008, Al Viro wrote: > > you've just lost e.g. -EIO for getdents(). And if you bail out on > non-zero return value from vfs_readdir(), you are back to -EINVAL > on full buffer. Btw, this whole sentence, and the one from your next email seems to really show a fundamental misunderstanding of the whole readdir() error handling: > PS: we might get away with both, if we used _positive_ values as well. > E.g. have getdents() filldir return 1 if we are out of buffer *and* > have ->previous != NULL (and -EINVAL if we are out of buffer on the > first call)... And have some other positive constant for "->readdir() > didn't feel like going all the way to the end of directory". We *must* handle partial returns by returning "success". And we do, except for our _confusion_ about ->readdir() returning error and that somehow "overriding" the fact that it already returned non-errors earlier through the callback. All your blathering about "positive values as well" seems to ttoally misunderstand how readdir() works. We absolutely do *not* need positive return values, because the fact is, the only positive return value we ever need is the "we already filled _earlier_ buffers". And that's the one that we already do. The fact is, NO ERROR VALUE CAN POSSIBLY MATTER if we already returned one or more entries to getdents/readdir(). We should return a success value. Linus