From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754138AbdHEAC1 (ORCPT ); Fri, 4 Aug 2017 20:02:27 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:48146 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753390AbdHDX0Z (ORCPT ); Fri, 4 Aug 2017 19:26:25 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Filipe Manana , Liu Bo , David Sterba , Sasha Levin Subject: [PATCH 4.9 080/105] Btrfs: fix lockdep warning about log_mutex Date: Fri, 4 Aug 2017 16:15:48 -0700 Message-Id: <20170804231556.580874911@linuxfoundation.org> X-Mailer: git-send-email 2.13.4 In-Reply-To: <20170804231551.544678194@linuxfoundation.org> References: <20170804231551.544678194@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Liu Bo [ Upstream commit 781feef7e6befafd4d9787d1f7ada1f9ccd504e4 ] While checking INODE_REF/INODE_EXTREF for a corner case, we may acquire a different inode's log_mutex with holding the current inode's log_mutex, and lockdep has complained this with a possilble deadlock warning. Fix this by using mutex_lock_nested() when processing the other inode's log_mutex. Reviewed-by: Filipe Manana Signed-off-by: Liu Bo Signed-off-by: David Sterba Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/tree-log.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -37,6 +37,7 @@ */ #define LOG_INODE_ALL 0 #define LOG_INODE_EXISTS 1 +#define LOG_OTHER_INODE 2 /* * directory trouble cases @@ -4623,7 +4624,7 @@ static int btrfs_log_inode(struct btrfs_ if (S_ISDIR(inode->i_mode) || (!test_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags) && - inode_only == LOG_INODE_EXISTS)) + inode_only >= LOG_INODE_EXISTS)) max_key.type = BTRFS_XATTR_ITEM_KEY; else max_key.type = (u8)-1; @@ -4647,7 +4648,13 @@ static int btrfs_log_inode(struct btrfs_ return ret; } - mutex_lock(&BTRFS_I(inode)->log_mutex); + if (inode_only == LOG_OTHER_INODE) { + inode_only = LOG_INODE_EXISTS; + mutex_lock_nested(&BTRFS_I(inode)->log_mutex, + SINGLE_DEPTH_NESTING); + } else { + mutex_lock(&BTRFS_I(inode)->log_mutex); + } /* * a brute force approach to making sure we get the most uptodate @@ -4799,7 +4806,7 @@ again: * unpin it. */ err = btrfs_log_inode(trans, root, other_inode, - LOG_INODE_EXISTS, + LOG_OTHER_INODE, 0, LLONG_MAX, ctx); iput(other_inode); if (err)