cachefiles: cancel all requests for the object that is being dropped

Because after an object is dropped, requests for that object are useless,
cancel them to avoid causing other problems.

This prepares for the later addition of cancel_work_sync(). After the
reopen requests is generated, cancel it to avoid cancel_work_sync()
blocking by waiting for daemon to complete the reopen requests.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Link: https://lore.kernel.org/r/20240628062930.2467993-7-libaokun@huaweicloud.com


Acked-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>