Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.4 06/24] ext4: protect group inode free counting with group lock | Date | Tue, 18 Feb 2014 14:46:53 -0800 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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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);
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