| From 6f2e9f0e7d795214b9cf5a47724a273b705fd113 Mon Sep 17 00:00:00 2001 |
| From: Tao Ma <boyu.mt@taobao.com> |
| Date: Mon, 28 May 2012 18:20:59 -0400 |
| Subject: ext4: protect group inode free counting with group lock |
| |
| From: Tao Ma <boyu.mt@taobao.com> |
| |
| commit 6f2e9f0e7d795214b9cf5a47724a273b705fd113 upstream. |
| |
| 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. |
| |
| Signed-off-by: Tao Ma <boyu.mt@taobao.com> |
| Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> |
| Signed-off-by: Benjamin LaHaise <bcrl@kvack.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| |
| --- |
| fs/ext4/ialloc.c | 4 +++- |
| 1 file changed, 3 insertions(+), 1 deletion(-) |
| |
| --- a/fs/ext4/ialloc.c |
| +++ b/fs/ext4/ialloc.c |
| @@ -778,6 +778,8 @@ 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)) { |
| @@ -790,8 +792,8 @@ got: |
| } |
| 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(group_desc_bh, "call ext4_handle_dirty_metadata"); |
| err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh); |