Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759415AbXERLEV (ORCPT ); Fri, 18 May 2007 07:04:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755146AbXERLEM (ORCPT ); Fri, 18 May 2007 07:04:12 -0400 Received: from e4.ny.us.ibm.com ([32.97.182.144]:54282 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755060AbXERLEK (ORCPT ); Fri, 18 May 2007 07:04:10 -0400 Date: Fri, 18 May 2007 16:40:42 +0530 From: Bharata B Rao To: Jan Engelhardt Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jan Blunck Subject: Re: [RFC][PATCH 10/14] In-kernel file copy between union mounted filesystems Message-ID: <20070518111042.GC4869@in.ibm.com> Reply-To: bharata@linux.vnet.ibm.com References: <20070514093722.GB4139@in.ibm.com> <20070514094329.GL4139@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1702 Lines: 51 On Wed, May 16, 2007 at 09:57:28AM +0200, Jan Engelhardt wrote: > > On May 14 2007 15:13, Bharata B Rao wrote: > >+ > >+ if (flag & 0x2) { > >+ error = union_copyup(nd, flag); > >+ if (error) > >+ goto exit; > >+ } > > What I dislike (and that also goes for fs/namei.c and such) that they use > numeral constants, i.e. 0x2. That seems error-prone. Could this (and > the in-kernel users of 0x1/0x2/0x4) be turned into some constant? > > >+ if (IS_DEADDIR(parent->d_inode)) > >+ goto error; > >+ err = -EACCES; /* shouldn't it be ENOSYS? */ > > I do not think so. ENOSYS means Syscall not implemented. But it is > implemented. If ->i_op is not there does not imply ENOSYS. > > Though, now that I grep through fs/*, I see that namei.c also > has that comment "shouldn't it be ENOSYS", so it's all at odds. > > >+ if (!parent->d_inode->i_op || !parent->d_inode->i_op->create) > >+ goto error; > > >+struct dentry * union_create_topmost(struct nameidata *nd, struct dentry *old) > >+{ > >+ struct dentry *dentry; > >+ struct dentry *parent = nd->dentry; > >+ > >+ UM_DEBUG_UID("dentry=%s\n", old->d_name.name); > >+ > >+ BUG_ON(parent->d_sb == old->d_sb); > >+ if (!S_ISREG(old->d_inode->i_mode)) { > >+ UM_DEBUG("This filetype isn't supported!\n"); > > Does that mean I cannot create block devices, etc.? > Not really. This is called during copyup of a file residing in a lower layer. And that is done only for regular files. Regards, Bharata. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/