From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965238AbbLXPph (ORCPT ); Thu, 24 Dec 2015 10:45:37 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51584 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754545AbbLXPme (ORCPT ); Thu, 24 Dec 2015 10:42:34 -0500 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, "Jan Kara" , "Theodore Ts'o" Date: Thu, 24 Dec 2015 15:37:42 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 34/77] jbd2: Fix unreclaimed pages after truncate in data=journal mode 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 3.2.75-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara commit bc23f0c8d7ccd8d924c4e70ce311288cb3e61ea8 upstream. Ted and Namjae have reported that truncated pages don't get timely reclaimed after being truncated in data=journal mode. The following test triggers the issue easily: for (i = 0; i < 1000; i++) { pwrite(fd, buf, 1024*1024, 0); fsync(fd); fsync(fd); ftruncate(fd, 0); } The reason is that journal_unmap_buffer() finds that truncated buffers are not journalled (jh->b_transaction == NULL), they are part of checkpoint list of a transaction (jh->b_cp_transaction != NULL) and have been already written out (!buffer_dirty(bh)). We clean such buffers but we leave them in the checkpoint list. Since checkpoint transaction holds a reference to the journal head, these buffers cannot be released until the checkpoint transaction is cleaned up. And at that point we don't call release_buffer_page() anymore so pages detached from mapping are lingering in the system waiting for reclaim to find them and free them. Fix the problem by removing buffers from transaction checkpoint lists when journal_unmap_buffer() finds out they don't have to be there anymore. Reported-and-tested-by: Namjae Jeon Fixes: de1b794130b130e77ffa975bb58cb843744f9ae5 Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o Signed-off-by: Ben Hutchings --- fs/jbd2/transaction.c | 2 ++ 1 file changed, 2 insertions(+) --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -1876,6 +1876,7 @@ static int journal_unmap_buffer(journal_ if (!buffer_dirty(bh)) { /* bdflush has written it. We can drop it now */ + __jbd2_journal_remove_checkpoint(jh); goto zap_buffer; } @@ -1913,6 +1914,7 @@ static int journal_unmap_buffer(journal_ /* The orphan record's transaction has * committed. We can cleanse this buffer */ clear_buffer_jbddirty(bh); + __jbd2_journal_remove_checkpoint(jh); goto zap_buffer; } }