From patchwork Wed Aug 12 08:55:11 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 506433 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 860F81401DE; Wed, 12 Aug 2015 18:58:23 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1ZPRrX-0003wf-Qq; Wed, 12 Aug 2015 08:58:19 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1ZPRqQ-00039P-RC for kernel-team@lists.ubuntu.com; Wed, 12 Aug 2015 08:57:10 +0000 Received: from av-217-129-142-138.netvisao.pt ([217.129.142.138] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1ZPRqQ-0004bE-AD; Wed, 12 Aug 2015 08:57:10 +0000 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.16.y-ckt 009/118] ext4: replace open coded nofail allocation in ext4_free_blocks() Date: Wed, 12 Aug 2015 09:55:11 +0100 Message-Id: <1439369820-27005-10-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1439369820-27005-1-git-send-email-luis.henriques@canonical.com> References: <1439369820-27005-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Cc: Michal Hocko , Theodore Ts'o X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.16.7-ckt16 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Michal Hocko commit 7444a072c387a93ebee7066e8aee776954ab0e41 upstream. ext4_free_blocks is looping around the allocation request and mimics __GFP_NOFAIL behavior without any allocation fallback strategy. Let's remove the open coded loop and replace it with __GFP_NOFAIL. Without the flag the allocator has no way to find out never-fail requirement and cannot help in any way. Signed-off-by: Michal Hocko Signed-off-by: Theodore Ts'o Signed-off-by: Luis Henriques --- fs/ext4/mballoc.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index c3e7418a6811..47f7af78675a 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4810,18 +4810,12 @@ do_more: /* * blocks being freed are metadata. these blocks shouldn't * be used until this transaction is committed + * + * We use __GFP_NOFAIL because ext4_free_blocks() is not allowed + * to fail. */ - retry: - new_entry = kmem_cache_alloc(ext4_free_data_cachep, GFP_NOFS); - if (!new_entry) { - /* - * We use a retry loop because - * ext4_free_blocks() is not allowed to fail. - */ - cond_resched(); - congestion_wait(BLK_RW_ASYNC, HZ/50); - goto retry; - } + new_entry = kmem_cache_alloc(ext4_free_data_cachep, + GFP_NOFS|__GFP_NOFAIL); new_entry->efd_start_cluster = bit; new_entry->efd_group = block_group; new_entry->efd_count = count_clusters;