!10137 NFSD: Fix ia_size underflow

Merge Pull Request from: @ci-robot 
 
PR sync from: Xia Fukun <xiafukun@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/K3JCNKZ36TCVG2OUNLANYOPYIWSGG2EH/ 
 
https://gitee.com/src-openeuler/kernel/issues/IADGCI 
 
Link:https://gitee.com/openeuler/kernel/pulls/10137

 

Reviewed-by: Liu YongQiang <liuyongqiang13@huawei.com>
Reviewed-by: Zucheng Zheng <zhengzucheng@huawei.com>
Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>