This series of patch tries to implement the get_dfs_refer operation for smb2. In smb2+, DFS resolving is now done through an FSCTL. The relevant Microsoft specifications for this are: MS-SMB2: 3.2.4.20 Application Requests an IO Control Code Operation MS-SMB2: 3.2.4.20.3 Application Requests DFS Referral Information MS-SMB2: 3.2.5.14 Receiving an SMB2 IOCTL Response MS-SMB2: 3.2.5.14.4 Handling a DFS Referral Information Response MS-DFSC: 2.2 Message Syntax (but really the whole document is useful) I've managed to make it work while keeping the same prototype for the operation but I believe it should be changed to be more correct and closer to the rest of the smb2 code. I've sucessfuly tested this against a Windows Server 2016 DFS setup. There are some things that I'm not sure how to do properly: * find the right tcon from the session object * find the IPC tcon from the share tcon I suspect these can be solved by changing the operation prototype so it provides the right objects (tcon, cifs_sb, ...). There are some things I've worked around: * SMB2_ioctl() explicitely checks for DFS requests and uses the IPC tid * since the tcon in build_path_from_dentry() does *not* have the IN_DFS_SHARE flag (I don't know why that is, because it is set in smbv1) I've added a new version of the function that uses an boolean argument to control whether or not to prefix the tree name. this version is only called once in the smb-generic code that deals with DFS. You will find more information in the commit messages. Any help solving these issues is welcome. Aurelien Aptel (6): fs/cifs: add smb2 fsctl payloads for DFS resolving fs/cifs: implement get_dfs_refer for smb2 fs/cifs: always use ipc for DFS resolving ioctls fs/cifs: add build_path_from_dentry_optional_prefix() fs/cifs: always use tree name prefix for DFS resolving fs/cifs: enable get_dfs_refer operation for smb2+ fs/cifs/cifs_dfs_ref.c | 2 +- fs/cifs/cifsproto.h | 1 + fs/cifs/dir.c | 12 ++- fs/cifs/smb2ops.c | 210 +++++++++++++++++++++++++++++++++++++++++++++++++ fs/cifs/smb2pdu.c | 4 + fs/cifs/smb2pdu.h | 15 ++++ 6 files changed, 241 insertions(+), 3 deletions(-) -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
