Run below script as root, dquot_add_space will return -EDQUOT since
__dquot_transfer call dquot_add_space with flags=0, and dquot_add_space
think it's a preallocation. Fix it by set flags as DQUOT_SPACE_WARN.
Fixes: 7b9ca4c61bc2 ("quota: Reduce contention on dq_data_lock") Signed-off-by: yangerkun <yangerkun@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz>