Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756121AbZJ0CVV (ORCPT ); Mon, 26 Oct 2009 22:21:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753085AbZJ0CVV (ORCPT ); Mon, 26 Oct 2009 22:21:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:27525 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752454AbZJ0CVT (ORCPT ); Mon, 26 Oct 2009 22:21:19 -0400 Date: Mon, 26 Oct 2009 22:21:01 -0400 From: Valerie Aurora To: David Woodhouse Cc: Jan Blunck , Alexander Viro , Christoph Hellwig , Andy Whitcroft , Scott James Remnant , Sandu Popa Marius , Jan Rekorajski , "J. R. Okajima" , Arnd Bergmann , Vladimir Dronnikov , Felix Fietkau , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org Subject: Re: [PATCH 16/41] whiteout: jffs2 whiteout support Message-ID: <20091027022101.GB14574@shell> References: <1256152779-10054-9-git-send-email-vaurora@redhat.com> <1256152779-10054-10-git-send-email-vaurora@redhat.com> <1256152779-10054-11-git-send-email-vaurora@redhat.com> <1256152779-10054-12-git-send-email-vaurora@redhat.com> <1256152779-10054-13-git-send-email-vaurora@redhat.com> <1256152779-10054-14-git-send-email-vaurora@redhat.com> <1256152779-10054-15-git-send-email-vaurora@redhat.com> <1256152779-10054-16-git-send-email-vaurora@redhat.com> <1256152779-10054-17-git-send-email-vaurora@redhat.com> <1256165449.22999.19.camel@macbook.infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1256165449.22999.19.camel@macbook.infradead.org> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4362 Lines: 103 On Thu, Oct 22, 2009 at 07:50:49AM +0900, David Woodhouse wrote: > On Wed, 2009-10-21 at 12:19 -0700, Valerie Aurora wrote: > > From: Felix Fietkau > > > > Add support for whiteout dentries to jffs2. > > As discussed, there are a few places where JFFS2 will assume that a > dirent with fd->ino == 0 is a deletion dirent -- a kind of whiteout of > its own, used internally because it's a log-structured file system and > it needs to mark previously existing dirents as having been unlinked. > > You're breaking that assumption. So, for example, your whiteouts are > going to get lost when the eraseblock containing them is garbage > collected -- because they'll be treated like deletion dirents, which > only need to remain on the medium for as long as the _real_ dirents > which they exist to kill. > > This completely untested patch addresses some of it. I think you are right. Thanks! I will add JFFS2 to my test suite before the next release. Right now I am testing mostly on UML, which doesn't support the RAM-based MTD emulator as far I can tell. > The other thing to verify is the three places in dir.c which check > whether whiteout/rmdir/rename should return -ENOTEMPTY. Those all do so > by checking whether the directory in question has any dirents with > fd->ino != 0 -- i.e. does it contain any _real_ dirents, or only the > deletion markers for dead stuff. > > So that will now be _allowing_ you to remove a directory which contains > whiteouts, since you haven't changed the test. Is that intentional? It > seems sane at first glance. Yes, you should be able to remove a directory which contains only union mount-level whiteouts. -VAL > diff --git a/fs/jffs2/build.c b/fs/jffs2/build.c > index c5e1450..4dc883f 100644 > --- a/fs/jffs2/build.c > +++ b/fs/jffs2/build.c > @@ -217,8 +217,9 @@ static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *c, > ic->scan_dents = fd->next; > > if (!fd->ino) { > - /* It's a deletion dirent. Ignore it */ > - dbg_fsbuild("child \"%s\" is a deletion dirent, skipping...\n", fd->name); > + dbg_fsbuild("child \"%s\" is a %s, skipping...\n", > + fd->name, > + (fd->type == DT_WHT)?"whiteout":"deletion dirent"); > jffs2_free_full_dirent(fd); > continue; > } > diff --git a/fs/jffs2/gc.c b/fs/jffs2/gc.c > index 090c556..7f5afbb 100644 > --- a/fs/jffs2/gc.c > +++ b/fs/jffs2/gc.c > @@ -516,7 +516,7 @@ static int jffs2_garbage_collect_live(struct jffs2_sb_info *c, struct jffs2_era > break; > } > > - if (fd && fd->ino) { > + if (fd && (fd->ino || fd->type == DT_WHT)) { > ret = jffs2_garbage_collect_dirent(c, jeb, f, fd); > } else if (fd) { > ret = jffs2_garbage_collect_deletion_dirent(c, jeb, f, fd); > @@ -895,7 +895,7 @@ static int jffs2_garbage_collect_deletion_dirent(struct jffs2_sb_info *c, struct > continue; > > /* If the name length doesn't match, or it's another deletion dirent, skip */ > - if (rd->nsize != name_len || !je32_to_cpu(rd->ino)) > + if (rd->nsize != name_len || (!je32_to_cpu(rd->ino) && rd->type != DT_WHT)) > continue; > > /* OK, check the actual name now */ > diff --git a/fs/jffs2/write.c b/fs/jffs2/write.c > index ca29440..bcd4b86 100644 > --- a/fs/jffs2/write.c > +++ b/fs/jffs2/write.c > @@ -629,8 +629,9 @@ int jffs2_do_unlink(struct jffs2_sb_info *c, struct jffs2_inode_info *dir_f, > printk(KERN_WARNING "Deleting inode #%u with active dentry \"%s\"->ino #%u\n", > dead_f->inocache->ino, fd->name, fd->ino); > } else { > - D1(printk(KERN_DEBUG "Removing deletion dirent for \"%s\" from dir ino #%u\n", > - fd->name, dead_f->inocache->ino)); > + D1(printk(KERN_DEBUG "Removing %s for \"%s\" from dir ino #%u\n", > + (fd->type == DT_WHT)?"whiteout":"deletion dirent", > + fd->name, dead_f->inocache->ino)); > } > if (fd->raw) > jffs2_mark_node_obsolete(c, fd->raw); > > > -- > David Woodhouse Open Source Technology Centre > David.Woodhouse@intel.com Intel Corporation > -- 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/