ksmbd: preserve open change time across rename

ksmbd: preserve open change time across rename

inode ctime is updated when a file is renamed. ksmbd returned that
ctime directly as SMB2 ChangeTime for handle-based query information.
This makes ChangeTime change after a rename through an already-open
handle, while Windows keeps the handle's ChangeTime stable for this
case.

Store the SMB ChangeTime in struct ksmbd_file when the handle is opened
and use that value for create, close, and handle-based query information
responses.  If a client explicitly sets FILE_BASIC_INFORMATION
ChangeTime, update the stored value as well.

This fixes smbtorture smb2.rename.simple_modtime, which expects
ChangeTime and LastWriteTime to remain unchanged after renaming an
already-open file.

Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>