[CIFS] Fix setting time before epoch (negative time values)

xfstest generic/258 sets the time on a file to a negative value
(before 1970) which fails since do_div can not handle negative
numbers.  In addition 'normal' division of 64 bit values does
not build on 32 bit arch so have to workaround this by special
casing negative values in cifs_NTtimeToUnix

Samba server also has a bug with this (see samba bugzilla 7771)
but it works to Windows server.

Signed-off-by: Steve French <smfrench@gmail.com>
[SMB3] Fix oops when creating symlinks on smb3

We were not checking for symlink support properly for SMB2/SMB3
mounts so could oops when mounted with mfsymlinks when try
to create symlink when mfsymlinks on smb2/smb3 mounts

Signed-off-by: Steve French <smfrench@gmail.com>
Cc: <stable@vger.kernel.org> # 3.14+
CC: Sachin Prabhu <sprabhu@redhat.com>
Revert "cifs: No need to send SIGKILL to demux_thread during umount"

This reverts commit 52a36244443eabb594bdb63622ff2dd7a083f0e2.

Causes rmmod to fail for at least 7 seconds after unmount which
makes automated testing a little harder when reloading cifs.ko
between test runs.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
CC: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: Steve French <smfrench@gmail.com>
cifs: remove dead code

cifs provides two dummy functions 'sess_auth_lanman' and
'sess_auth_kerberos' for the case in which the respective
features are not defined. However, the caller is also under
an #ifdef, so we just get warnings about unused code:

fs/cifs/sess.c:1109:1: warning: 'sess_auth_kerberos' defined but not used [-Wunused-function]
 sess_auth_kerberos(struct sess_data *sess_data)

Removing the dead functions gets rid of the warnings without
any downsides that I can see.

(Yalin Wang reported the identical problem and fix so added him)

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Yalin Wang <yalin.wang@sonymobile.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Update version number displayed by modinfo for cifs.ko

Update cifs.ko version to 2.05

Signed-off-by: Steve French <smfrench@gmail.com>w
Fix mfsymlinks file size check

If the mfsymlinks file size has changed (e.g. the file no longer
represents an emulated symlink) we were not returning an error properly.

Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Merge branch 'for-linus' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs/smb3 fixes from Steve French:
 "Fixes for problems found during testing and debugging at the SMB3
  storage test event (plugfest) this week"

* 'for-linus' of git://git.samba.org/sfrench/cifs-2.6:
  Fix mfsymlinks file size check
  Update version number displayed by modinfo for cifs.ko
  cifs: remove dead code
  Revert "cifs: No need to send SIGKILL to demux_thread during umount"
  [SMB3] Fix oops when creating symlinks on smb3
  [CIFS] Fix setting time before epoch (negative time values)