From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759667AbbJIATk (ORCPT ); Thu, 8 Oct 2015 20:19:40 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35208 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757260AbbJIAR3 (ORCPT ); Thu, 8 Oct 2015 20:17:29 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Theodore Ts'o" , "Bartosz Kwitniewski" , "Jan Kara" Date: Fri, 09 Oct 2015 01:12:27 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 003/107] jbd2: protect all log tail updates with j_checkpoint_mutex In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.247 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.72-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit a78bb11d7acd525623c6a0c2ff4e213d527573fa upstream. There are some log tail updates that are not protected by j_checkpoint_mutex. Some of these are harmless because they happen during startup or shutdown but updates in jbd2_journal_commit_transaction() and jbd2_journal_flush() can really race with other log tail updates (e.g. someone doing jbd2_journal_flush() with someone running jbd2_cleanup_journal_tail()). So protect all log tail updates with j_checkpoint_mutex. Signed-off-by: Jan Kara Signed-off-by: "Theodore Ts'o" [bwh: Backported to 3.2: - Adjust context - Add unlock on the error path in jbd2_journal_flush()] Signed-off-by: Ben Hutchings Cc: Bartosz Kwitniewski --- fs/jbd2/commit.c | 2 ++ fs/jbd2/journal.c | 19 ++++++++++++++++--- 2 files changed, 18 insertions(+), 3 deletions(-) --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c @@ -340,6 +340,7 @@ void jbd2_journal_commit_transaction(jou /* Do we need to erase the effects of a prior jbd2_journal_flush? */ if (journal->j_flags & JBD2_FLUSHED) { jbd_debug(3, "super block updated\n"); + mutex_lock(&journal->j_checkpoint_mutex); /* * We hold j_checkpoint_mutex so tail cannot change under us. * We don't need any special data guarantees for writing sb @@ -350,6 +351,7 @@ void jbd2_journal_commit_transaction(jou journal->j_tail_sequence, journal->j_tail, WRITE_SYNC); + mutex_unlock(&journal->j_checkpoint_mutex); } else { jbd_debug(3, "superblock not updated\n"); } --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -1242,6 +1242,8 @@ static int journal_reset(journal_t *jour journal->j_errno); journal->j_flags |= JBD2_FLUSHED; } else { + /* Lock here to make assertions happy... */ + mutex_lock(&journal->j_checkpoint_mutex); /* * Update log tail information. We use WRITE_FUA since new * transaction will start reusing journal space and so we @@ -1252,6 +1254,7 @@ static int journal_reset(journal_t *jour journal->j_tail_sequence, journal->j_tail, WRITE_FUA); + mutex_unlock(&journal->j_checkpoint_mutex); } return jbd2_journal_start_thread(journal); } @@ -1314,6 +1317,7 @@ int jbd2_journal_update_sb_log_tail(jour journal_superblock_t *sb = journal->j_superblock; int ret; + BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex)); jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n", tail_block, tail_tid); @@ -1344,6 +1348,7 @@ static void jbd2_mark_journal_empty(jour { journal_superblock_t *sb = journal->j_superblock; + BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex)); read_lock(&journal->j_state_lock); jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n", journal->j_tail_sequence); @@ -1577,9 +1582,11 @@ int jbd2_journal_destroy(journal_t *jour spin_unlock(&journal->j_list_lock); if (journal->j_sb_buffer) { - if (!is_journal_aborted(journal)) + if (!is_journal_aborted(journal)) { + mutex_lock(&journal->j_checkpoint_mutex); jbd2_mark_journal_empty(journal); - else + mutex_unlock(&journal->j_checkpoint_mutex); + } else err = -EIO; brelse(journal->j_sb_buffer); } @@ -1828,10 +1835,13 @@ int jbd2_journal_flush(journal_t *journa if (is_journal_aborted(journal)) return -EIO; + mutex_lock(&journal->j_checkpoint_mutex); if (!err) { err = jbd2_cleanup_journal_tail(journal); - if (err < 0) + if (err < 0) { + mutex_unlock(&journal->j_checkpoint_mutex); goto out; + } err = 0; } @@ -1841,6 +1851,7 @@ int jbd2_journal_flush(journal_t *journa * commits of data to the journal will restore the current * s_start value. */ jbd2_mark_journal_empty(journal); + mutex_unlock(&journal->j_checkpoint_mutex); write_lock(&journal->j_state_lock); J_ASSERT(!journal->j_running_transaction); J_ASSERT(!journal->j_committing_transaction); @@ -1882,8 +1893,12 @@ int jbd2_journal_wipe(journal_t *journal write ? "Clearing" : "Ignoring"); err = jbd2_journal_skip_recovery(journal); - if (write) + if (write) { + /* Lock to make assertions happy... */ + mutex_lock(&journal->j_checkpoint_mutex); jbd2_mark_journal_empty(journal); + mutex_unlock(&journal->j_checkpoint_mutex); + } no_recovery: return err;