[PATCH] ext4: remove abnormal set for I_DATA_SEM subclass

[Junil Lee]

The -EBUSY return value of dquot_enable() function means that just
want to update flags. If some users make a duplicate request to update
flags, lockdep could catch the false positive casued by needing to
allocate a quota block from inside ext4_map_blocks(), while holding
i_data_sem for a data inode. This results in this comlaint:

       CPU0                    CPU1
       ----                    ----
  lock(&s->s_dquot.dqio_mutex);
                               lock(&ei->i_data_sem);
                               lock(&s->s_dquot.dqio_mutex);
  lock(&ei->i_data_sem);

Signed-off-by: Junil Lee <junil0814....@lge.com>
---
 fs/ext4/super.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 13d2706..f16c92d 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5637,7 +5637,7 @@ static int ext4_quota_enable(struct super_block *sb, int 
type, int format_id,
        lockdep_set_quota_inode(qf_inode, I_DATA_SEM_QUOTA);
        err = dquot_enable(qf_inode, type, format_id, flags);
        iput(qf_inode);
-       if (err)
+       if (err != -EBUSY)
                lockdep_set_quota_inode(qf_inode, I_DATA_SEM_NORMAL);
 
        return err;
-- 
2.6.2