smb: client: set correct d_type for reparse DFS/DFSR and mount point

Set correct dirent->d_type for IO_REPARSE_TAG_DFS{,R} and
IO_REPARSE_TAG_MOUNT_POINT reparse points.

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: parse uid, gid, mode and dev from WSL reparse points

Parse the extended attributes from WSL reparse points to correctly
report uid, gid mode and dev from ther instantiated inodes.

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: introduce SMB2_OP_QUERY_WSL_EA

Add a new command to smb2_compound_op() for querying WSL extended
attributes from reparse points.

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: Fix a NULL vs IS_ERR() check in wsl_set_xattrs()

This was intended to be an IS_ERR() check. The ea_create_context()
function doesn't return NULL.

Fixes: 1eab17fe485c ("smb: client: add support for WSL reparse points")
Reviewed-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: add support for WSL reparse points

Add support for creating special files via WSL reparse points when
using 'reparse=wsl' mount option. They're faster than NFS reparse
points because they don't require extra roundtrips to figure out what
->d_type a specific dirent is as such information is already stored in
query dir responses and then making getdents() calls faster.

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: move most of reparse point handling code to common file

In preparation to add support for creating special files also via WSL
reparse points in next commits.

Signed-off-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>