fs: provide locked helper variant of close_fd_get_file()

mainline inclusion
from mainline-v5.12-rc1
commit 53dec2ea
category: bugfix
bugzilla: 188963, https://gitee.com/src-openeuler/kernel/issues/I7GUAN


CVE: NA

--------------------------------

Assumes current->files->file_lock is already held on invocation. Helps
the caller check the file before removing the fd, if it needs to.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

Conflicts:
	fs/file.c
	fs/internal.h

Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yang Erkun <yangerkun@huawei.com>
Reviewed-by: Wang Weiyang <wangweiyang2@huawei.com>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>