From: akpm@linux-foundation.org Subject: [patch 195/268] ext3: fix deadlock in ext3_remount() and orphan list handling Date: Sun, 15 Jul 2007 23:41:08 -0700 Message-ID: <200707160641.l6G6f8aT014974@imap1.linux-foundation.org> Cc: akpm@linux-foundation.org, jack@suse.cz, linux-ext4@vger.kernel.org, sandeen@sandeen.net To: torvalds@linux-foundation.org Return-path: Received: from smtp2.linux-foundation.org ([207.189.120.14]:46447 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753366AbXGPGss (ORCPT ); Mon, 16 Jul 2007 02:48:48 -0400 Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org From: Jan Kara ext3_orphan_add() and ext3_orphan_del() functions lock sb->s_lock with a transaction started with ext3_mark_recovery_complete() waits for a transaction holding sb->s_lock, thus leading to a possible deadlock. At the moment we call ext3_mark_recovery_complete() from ext3_remount() we have done all the work needed for remounting and thus we are safe to drop sb->s_lock before we wait for transactions to commit. Note that at this moment we are still guarded by s_umount lock against other remounts/umounts. Signed-off-by: Jan Kara Cc: Eric Sandeen Cc: Signed-off-by: Andrew Morton --- fs/ext3/super.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff -puN fs/ext3/super.c~ext3-fix-deadlock-in-ext3_remount-and-orphan-list-handling fs/ext3/super.c --- a/fs/ext3/super.c~ext3-fix-deadlock-in-ext3_remount-and-orphan-list-handling +++ a/fs/ext3/super.c @@ -2147,12 +2147,14 @@ static void ext3_mark_recovery_complete( journal_lock_updates(journal); journal_flush(journal); + lock_super(sb); if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER) && sb->s_flags & MS_RDONLY) { EXT3_CLEAR_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER); sb->s_dirt = 0; ext3_commit_super(sb, es, 1); } + unlock_super(sb); journal_unlock_updates(journal); } @@ -2341,7 +2343,13 @@ static int ext3_remount (struct super_bl (sbi->s_mount_state & EXT3_VALID_FS)) es->s_state = cpu_to_le16(sbi->s_mount_state); + /* + * We have to unlock super so that we can wait for + * transactions. + */ + unlock_super(sb); ext3_mark_recovery_complete(sb, es); + lock_super(sb); } else { __le32 ret; if ((ret = EXT3_HAS_RO_COMPAT_FEATURE(sb, _