Version 2 of the patch. Thanks to Dan Carpenter and the smatch
tool for finding a problem in the first version of this patch.

CC: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NPavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: NSteve French <steve.french@primarydata.com>

Signed-off-by: NSteve French <steve.french@primarydata.com>

 Getting fantastic copy performance with cp --reflink over SMB3.11
 using the new FSCTL_DUPLICATE_EXTENTS.

 This FSCTL was added in the SMB3.11 dialect (testing was
 against REFS file system) so have put it as a 3.11 protocol
 specific operation ("vers=3.1.1" on the mount).  Tested at
 the SMB3 plugfest in Redmond.

 It depends on the new FS Attribute (BLOCK_REFCOUNTING) which
 is used to advertise support for the ability to do this ioctl
 (if you can support multiple files pointing to the same block
 than this refcounting ability or equivalent is needed to
 support the new reflink-like duplicate extent SMB3 ioctl.
Signed-off-by: NSteve French <steve.french@primarydata.com>

Implement FALLOC_FL_PUNCH_HOLE (which does not change the file size
fortunately so this matches the behavior of the equivalent SMB3
fsctl call) for SMB3 mounts.  This allows "fallocate -p" to work.
It requires that the server support setting files as sparse
(which Windows allows).
Signed-off-by: NSteve French <smfrench@gmail.com>

When we are running SMB3 or SMB3.02 connections which are signed
we need to validate the protocol negotiation information,
to ensure that the negotiate protocol response was not tampered with.

Add the missing FSCTL which is sent at mount time (immediately after
the SMB3 Tree Connect) to validate that the capabilities match
what we think the server sent.

"Secure dialect negotiation is introduced in SMB3 to protect against
man-in-the-middle attempt to downgrade dialect negotiation.
The idea is to prevent an eavesdropper from downgrading the initially
negotiated dialect and capabilities between the client and the server."

For more explanation see 2.2.31.4 of MS-SMB2 or
http://blogs.msdn.com/b/openspecification/archive/2012/06/28/smb3-secure-dialect-negotiation.aspxReviewed-by: NPavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: NSteve French <smfrench@gmail.com>

Windows 8 and later can create NFS symlinks (within reparse points)
which we were assuming were normal NTFS symlinks and thus reporting
corrupt paths for.  Add check for reparse points to make sure that
they really are normal symlinks before we try to parse the pathname.

We also should not be parsing other types of reparse points (DFS
junctions etc) as if they were a  symlink so return EOPNOTSUPP
on those.  Also fix endian errors (we were not parsing symlink
lengths as little endian).

This fixes commit d244bf2d
which implemented follow link for non-Unix CIFS mounts

CC: Stable <stable@kernel.org>
Reviewed-by: NAndrew Bartlett <abartlet@samba.org>
Signed-off-by: NSteve French <smfrench@gmail.com>

MS-SMB2 Section 2.2.31 lists fsctls.  Update our list of valid
cifs/smb2/smb3 fsctls and some related structs
based on more recent version of docs.  Additional detail on
less common ones can be found in MS-FSCC section 2.3.

CopyChunk (server side copy, ie refcopy) will depend on a few
of these
Signed-off-by: NSteve French <smfrench@gmail.com>

There are about 60 fsctl calls which Windows claims would be able
to be sent remotely and handled by the server. This adds the #defines
for them.  A few of them look immediately useful, but need to also
add the structure definitions for them so they can be sent as SMBs.
Signed-off-by: NSteve French <sfrench@us.ibm.com>