From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965483Ab3GSFrE (ORCPT ); Fri, 19 Jul 2013 01:47:04 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:39412 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965422Ab3GSFWY (ORCPT ); Fri, 19 Jul 2013 01:22:24 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Nagachandra P , "Theodore Tso" Subject: [ 34/38] ext4: dont allow ext4_free_blocks() to fail due to ENOMEM Date: Thu, 18 Jul 2013 22:21:50 -0700 Message-Id: <20130719052050.209212357@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <20130719052047.858393825@linuxfoundation.org> References: <20130719052047.858393825@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit e7676a704ee0a1ef71a6b23760b5a8f6896cb1a1 upstream. The filesystem should not be marked inconsistent if ext4_free_blocks() is not able to allocate memory. Unfortunately some callers (most notably ext4_truncate) don't have a way to reflect an error back up to the VFS. And even if we did, most userspace applications won't deal with most system calls returning ENOMEM anyway. Reported-by: Nagachandra P Signed-off-by: "Theodore Ts'o" Signed-off-by: Greg Kroah-Hartman --- fs/ext4/mballoc.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4622,11 +4622,16 @@ do_more: * blocks being freed are metadata. these blocks shouldn't * be used until this transaction is committed */ + retry: new_entry = kmem_cache_alloc(ext4_free_data_cachep, GFP_NOFS); if (!new_entry) { - ext4_mb_unload_buddy(&e4b); - err = -ENOMEM; - goto error_return; + /* + * 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->efd_start_cluster = bit; new_entry->efd_group = block_group;