From: Tao Ma Subject: [PATCH V2] ext4: Protect group inode free counting with group lock. Date: Thu, 17 May 2012 15:35:39 +0800 Message-ID: <1337240139-5005-1-git-send-email-tm@tao.ma> Cc: Theodore Ts'o To: linux-ext4@vger.kernel.org Return-path: Received: from oproxy6-pub.bluehost.com ([67.222.54.6]:36024 "HELO oproxy6-pub.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1761292Ab2EQHfu (ORCPT ); Thu, 17 May 2012 03:35:50 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: From: Tao Ma Now when we set the group inode free count, we don't have a proper group lock so that multiple threads may decrease the inode free count at the same time. And e2fsck will complain something like: Free inodes count wrong for group #1 (1, counted=0). Fix? no Free inodes count wrong for group #2 (3, counted=0). Fix? no Directories count wrong for group #2 (780, counted=779). Fix? no Free inodes count wrong for group #3 (2272, counted=2273). Fix? no So this patch try to protect it with the ext4_lock_group. btw, it is found by xfstests test case 269 and the volume is mkfsed with the parameter "-O ^resize_inode,^uninit_bg,extent,meta_bg,flex_bg,ext_attr" and I have run it 100 times and the error in e2fsck doesn't show up again. Cc: Theodore Ts'o Signed-off-by: Tao Ma --- fs/ext4/ialloc.c | 8 +++++--- 1 files changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 409c2ee..ca533d7 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -772,7 +772,10 @@ got: ext4_itable_unused_set(sb, gdp, (EXT4_INODES_PER_GROUP(sb) - ino)); up_read(&grp->alloc_sem); + } else { + ext4_lock_group(sb, group); } + ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1); if (S_ISDIR(mode)) { ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1); @@ -782,10 +785,9 @@ got: atomic_inc(&sbi->s_flex_groups[f].used_dirs); } } - if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) { + if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp); - ext4_unlock_group(sb, group); - } + ext4_unlock_group(sb, group); BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata"); err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh); -- 1.7.1