From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760109Ab3GaNil (ORCPT ); Wed, 31 Jul 2013 09:38:41 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:47052 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759811Ab3GaNZ5 (ORCPT ); Wed, 31 Jul 2013 09:25:57 -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, "Nagachandra P" , "Theodore Ts'o" Date: Wed, 31 Jul 2013 15:23:09 +0200 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [37/84] ext4: don't allow ext4_free_blocks() to fail due to ENOMEM In-Reply-To: X-SA-Exim-Connect-IP: 151.216.67.181 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 3.2.50-rc1 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" [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- fs/ext4/mballoc.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4696,11 +4696,16 @@ 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_ext_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->start_cluster = bit; new_entry->group = block_group;