From patchwork Thu Jul 31 23:10:32 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Filipe Manana X-Patchwork-Id: 4659311 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id F15A09F2B8 for ; Thu, 31 Jul 2014 22:11:02 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C22922015E for ; Thu, 31 Jul 2014 22:11:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8E2282011E for ; Thu, 31 Jul 2014 22:11:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750914AbaGaWK5 (ORCPT ); Thu, 31 Jul 2014 18:10:57 -0400 Received: from victor.provo.novell.com ([137.65.250.26]:44002 "EHLO victor.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750789AbaGaWK4 (ORCPT ); Thu, 31 Jul 2014 18:10:56 -0400 Received: from debian-vm3.lan (prv-ext-foundry1int.gns.novell.com [137.65.251.240]) by victor.provo.novell.com with ESMTP (NOT encrypted); Thu, 31 Jul 2014 16:10:50 -0600 From: Filipe Manana To: linux-btrfs@vger.kernel.org Cc: Filipe Manana Subject: [PATCH] Btrfs: ensure tmpfile inode is always persisted with link count of 0 Date: Fri, 1 Aug 2014 00:10:32 +0100 Message-Id: <1406848232-16269-1-git-send-email-fdmanana@suse.com> X-Mailer: git-send-email 1.9.1 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Spam-Status: No, score=-7.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If we open a file with O_TMPFILE, don't do any further operation on it (so that the inode item isn't updated) and then force a transaction commit, we get a persisted inode item with a link count of 1, and not 0 as it should be. Steps to reproduce it (requires a modern xfs_io with -T support): $ mkfs.btrfs -f /dev/sdd $ mount -o /dev/sdd /mnt $ xfs_io -T /mnt & $ sync Then btrfs-debug-tree shows the inode item with a link count of 1: $ btrfs-debug-tree /dev/sdd (...) fs tree key (FS_TREE ROOT_ITEM 0) leaf 29556736 items 4 free space 15851 generation 6 owner 5 fs uuid f164d01b-1b92-481d-a4e4-435fb0f843d0 chunk uuid 0e3d0e56-bcca-4a1c-aa5f-cec2c6f4f7a6 item 0 key (256 INODE_ITEM 0) itemoff 16123 itemsize 160 inode generation 3 transid 6 size 0 block group 0 mode 40755 links 1 item 1 key (256 INODE_REF 256) itemoff 16111 itemsize 12 inode ref index 0 namelen 2 name: .. item 2 key (257 INODE_ITEM 0) itemoff 15951 itemsize 160 inode generation 6 transid 6 size 0 block group 0 mode 100600 links 1 item 3 key (ORPHAN ORPHAN_ITEM 257) itemoff 15951 itemsize 0 orphan item checksum tree key (CSUM_TREE ROOT_ITEM 0) (...) Signed-off-by: Filipe Manana --- fs/btrfs/inode.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 4f35c6c..8ad3ea9 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -5688,6 +5688,13 @@ static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans, } /* + * O_TMPFILE, set link count to 0, so that after this point, + * we fill in an inode item with the correct link count. + */ + if (!name) + set_nlink(inode, 0); + + /* * we have to initialize this early, so we can reclaim the inode * number if we fail afterwards in this function. */ @@ -9133,6 +9140,14 @@ static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) if (ret) goto out; + /* + * We set number of links to 0 in btrfs_new_inode(), and here we set + * it to 1 because d_tmpfile() will issue a warning if the count is 0, + * through: + * + * d_tmpfile() -> inode_dec_link_count() -> drop_nlink() + */ + set_nlink(inode, 1); d_tmpfile(dentry, inode); mark_inode_dirty(inode);