From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755111AbcAXWDB (ORCPT ); Sun, 24 Jan 2016 17:03:01 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:60460 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753423AbcAXWBu (ORCPT ); Sun, 24 Jan 2016 17:01:50 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Jan Kara , "Theodore Ts'o" , Luis Henriques Subject: [PATCH 3.16.y-ckt 008/128] jbd2: Fix unreclaimed pages after truncate in data=journal mode Date: Sun, 24 Jan 2016 21:59:23 +0000 Message-Id: <1453672883-2708-9-git-send-email-luis.henriques@canonical.com> In-Reply-To: <1453672883-2708-1-git-send-email-luis.henriques@canonical.com> References: <1453672883-2708-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.7-ckt23 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ 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: Luis Henriques --- fs/jbd2/transaction.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index 99ebbd72a064..77303ba0c270 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -2064,6 +2064,7 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh, if (!buffer_dirty(bh)) { /* bdflush has written it. We can drop it now */ + __jbd2_journal_remove_checkpoint(jh); goto zap_buffer; } @@ -2093,6 +2094,7 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh, /* The orphan record's transaction has * committed. We can cleanse this buffer */ clear_buffer_jbddirty(bh); + __jbd2_journal_remove_checkpoint(jh); goto zap_buffer; } }