From: Eric Sandeen Subject: [PATCH] ext4: fix freespace accounting with mballoc on 32bit machines Date: Thu, 25 Oct 2007 15:08:06 -0500 Message-ID: <4720F7A6.9060905@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Alex Tomas , Mingming Cao , Andrew Morton To: ext4 development Return-path: Received: from mx1.redhat.com ([66.187.233.31]:34079 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752563AbXJYUKw (ORCPT ); Thu, 25 Oct 2007 16:10:52 -0400 Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On a 32bit machine, passing the negative unsigned long fe_len into percpu_counter_add (which expects s64) messes up the counters: [root@bear-05 linux-2.6.23-rc7]# df -h Filesystem Size Used Avail Use% Mounted on /dev/sdb7 97G -149P 149P - /mnt/test Patch below fixes this. Signed-off-by: Eric Sandeen --- linux.orig/fs/ext4/mballoc.c 2007-10-25 14:47:25.048435451 -0500 +++ linux/fs/ext4/mballoc.c 2007-10-25 14:47:35.815160682 -0500 @@ -3005,7 +3005,7 @@ - ac->ac_b_ex.fe_len); gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp); spin_unlock(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group)); - percpu_counter_add(&sbi->s_freeblocks_counter, - ac->ac_b_ex.fe_len); + percpu_counter_sub(&sbi->s_freeblocks_counter, ac->ac_b_ex.fe_len); err = ext4_journal_dirty_metadata(handle, bitmap_bh); if (err)