1====
2TODO
3====
4
5Version 2.14 December 21, 2018
6
7A Partial List of Missing Features
8==================================
9
10Contributions are welcome.  There are plenty of opportunities
11for visible, important contributions to this module.  Here
12is a partial list of the known problems and missing features:
13
14a) SMB3 (and SMB3.1.1) missing optional features:
15
16   - multichannel (started), integration with RDMA
17   - directory leases (improved metadata caching), started (root dir only)
18   - T10 copy offload ie "ODX" (copy chunk, and "Duplicate Extents" ioctl
19     currently the only two server side copy mechanisms supported)
20
21b) improved sparse file support (fiemap and SEEK_HOLE are implemented
22   but additional features would be supportable by the protocol).
23
24c) Directory entry caching relies on a 1 second timer, rather than
25   using Directory Leases, currently only the root file handle is cached longer
26
27d) quota support (needs minor kernel change since quota calls
28   to make it to network filesystems or deviceless filesystems)
29
30e) Additional use cases can be optimized to use "compounding" (e.g.
31   open/query/close and open/setinfo/close) to reduce the number of
32   roundtrips to the server and improve performance. Various cases
33   (stat, statfs, create, unlink, mkdir) already have been improved by
34   using compounding but more can be done. In addition we could
35   significantly reduce redundant opens by using deferred close (with
36   handle caching leases) and better using reference counters on file
37   handles.
38
39f) Finish inotify support so kde and gnome file list windows
40   will autorefresh (partially complete by Asser). Needs minor kernel
41   vfs change to support removing D_NOTIFY on a file.
42
43g) Add GUI tool to configure /proc/fs/cifs settings and for display of
44   the CIFS statistics (started)
45
46h) implement support for security and trusted categories of xattrs
47   (requires minor protocol extension) to enable better support for SELINUX
48
49i) Add support for tree connect contexts (see MS-SMB2) a new SMB3.1.1 protocol
50   feature (may be especially useful for virtualization).
51
52j) Create UID mapping facility so server UIDs can be mapped on a per
53   mount or a per server basis to client UIDs or nobody if no mapping
54   exists. Also better integration with winbind for resolving SID owners
55
56k) Add tools to take advantage of more smb3 specific ioctls and features
57   (passthrough ioctl/fsctl is now implemented in cifs.ko to allow
58   sending various SMB3 fsctls and query info and set info calls
59   directly from user space) Add tools to make setting various non-POSIX
60   metadata attributes easier from tools (e.g. extending what was done
61   in smb-info tool).
62
63l) encrypted file support
64
65m) improved stats gathering tools (perhaps integration with nfsometer?)
66   to extend and make easier to use what is currently in /proc/fs/cifs/Stats
67
68n) Add support for claims based ACLs ("DAC")
69
70o) mount helper GUI (to simplify the various configuration options on mount)
71
72p) Add support for witness protocol (perhaps ioctl to cifs.ko from user space
73   tool listening on witness protocol RPC) to allow for notification of share
74   move, server failover, and server adapter changes.  And also improve other
75   failover scenarios, e.g. when client knows multiple DFS entries point to
76   different servers, and the server we are connected to has gone down.
77
78q) Allow mount.cifs to be more verbose in reporting errors with dialect
79   or unsupported feature errors.
80
81r) updating cifs documentation, and user guide.
82
83s) Addressing bugs found by running a broader set of xfstests in standard
84   file system xfstest suite.
85
86t) split cifs and smb3 support into separate modules so legacy (and less
87   secure) CIFS dialect can be disabled in environments that don't need it
88   and simplify the code.
89
90v) POSIX Extensions for SMB3.1.1 (started, create and mkdir support added
91   so far).
92
93w) Add support for additional strong encryption types, and additional spnego
94   authentication mechanisms (see MS-SMB2)
95
96x) Finish support for SMB3.1.1 compression
97
98Known Bugs
99==========
100
101See https://bugzilla.samba.org - search on product "CifsVFS" for
102current bug list.  Also check http://bugzilla.kernel.org (Product = File System, Component = CIFS)
103
1041) existing symbolic links (Windows reparse points) are recognized but
105   can not be created remotely. They are implemented for Samba and those that
106   support the CIFS Unix extensions, although earlier versions of Samba
107   overly restrict the pathnames.
1082) follow_link and readdir code does not follow dfs junctions
109   but recognizes them
110
111Misc testing to do
112==================
1131) check out max path names and max path name components against various server
114   types. Try nested symlinks (8 deep). Return max path name in stat -f information
115
1162) Improve xfstest's cifs/smb3 enablement and adapt xfstests where needed to test
117   cifs/smb3 better
118
1193) Additional performance testing and optimization using iozone and similar -
120   there are some easy changes that can be done to parallelize sequential writes,
121   and when signing is disabled to request larger read sizes (larger than
122   negotiated size) and send larger write sizes to modern servers.
123
1244) More exhaustively test against less common servers
125
1265) Continue to extend the smb3 "buildbot" which does automated xfstesting
127   against Windows, Samba and Azure currently - to add additional tests and
128   to allow the buildbot to execute the tests faster. The URL for the
129   buildbot is: http://smb3-test-rhel-75.southcentralus.cloudapp.azure.com
130
1316) Address various coverity warnings (most are not bugs per-se, but
132   the more warnings are addressed, the easier it is to spot real
133   problems that static analyzers will point out in the future).
134