From: akpm@linux-foundation.org Subject: + ext4-fix-deadlock-in-ext4_remount-and-orphan-list-handling.patch added to -mm tree Date: Tue, 12 Jun 2007 14:03:29 -0700 Message-ID: <200706122103.l5CL3Tti021131@imap1.linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Cc: jack@suse.cz, linux-ext4@vger.kernel.org, sandeen@sandeen.net To: mm-commits@vger.kernel.org Return-path: Sender: mm-commits-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org The patch titled ext4: fix deadlock in ext4_remount() and orphan list handling has been added to the -mm tree. Its filename is ext4-fix-deadlock-in-ext4_remount-and-orphan-list-handling.patch *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this ------------------------------------------------------ Subject: ext4: fix deadlock in ext4_remount() and orphan list handling From: Jan Kara ext4_orphan_add() and ext4_orphan_del() functions lock sb->s_lock with a transaction started with ext4_mark_recovery_complete() waits for a transaction holding sb->s_lock, thus leading to a possible deadlock. At the moment we call ext4_mark_recovery_complete() from ext4_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/ext4/super.c | 8 ++++++++ 1 files changed, 8 insertions(+) diff -puN fs/ext4/super.c~ext4-fix-deadlock-in-ext4_remount-and-orphan-list-handling fs/ext4/super.c --- a/fs/ext4/super.c~ext4-fix-deadlock-in-ext4_remount-and-orphan-list-handling +++ a/fs/ext4/super.c @@ -2222,12 +2222,14 @@ static void ext4_mark_recovery_complete( jbd2_journal_lock_updates(journal); jbd2_journal_flush(journal); + lock_super(sb); if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER) && sb->s_flags & MS_RDONLY) { EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER); sb->s_dirt = 0; ext4_commit_super(sb, es, 1); } + unlock_super(sb); jbd2_journal_unlock_updates(journal); } @@ -2416,7 +2418,13 @@ static int ext4_remount (struct super_bl (sbi->s_mount_state & EXT4_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); ext4_mark_recovery_complete(sb, es); + lock_super(sb); } else { __le32 ret; if ((ret = EXT4_HAS_RO_COMPAT_FEATURE(sb, _ Patches currently in -mm which might be from jack@suse.cz are udf-fix-possible-leakage-of-blocks.patch udf-fix-possible-leakage-of-blocks-fix.patch ext2-fix-a-comment-when-ext2_release_file-is-called.patch ext3-fix-deadlock-in-ext3_remount-and-orphan-list-handling.patch ext4-fix-deadlock-in-ext4_remount-and-orphan-list-handling.patch