!3090 fs/dcache.c: avoid softlock since too many negative dentry

Merge Pull Request from: @ci-robot 
 
PR sync from: Zizhi Wo <wozizhi@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/Y4EU2BFJBBC44JXYWWTNTEFY2LJAQLVI/ 
 
https://gitee.com/openeuler/kernel/issues/I8JH5M?from=project-issue 
 
Link:https://gitee.com/openeuler/kernel/pulls/3090

 

Reviewed-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>