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1Version 2.11 September 13, 2017
2
3A Partial List of Missing Features
4==================================
5
6Contributions are welcome. There are plenty of opportunities
7for visible, important contributions to this module. Here
8is a partial list of the known problems and missing features:
9
10a) SMB3 (and SMB3.02) missing optional features:
11 - multichannel (started), integration with RDMA
12 - directory leases (improved metadata caching)
13 - T10 copy offload (copy chunk, and "Duplicate Extents" ioctl
14 currently the only two server side copy mechanisms supported)
15
16b) improved sparse file support
17
18c) Directory entry caching relies on a 1 second timer, rather than
19using Directory Leases
20
21d) quota support (needs minor kernel change since quota calls
22to make it to network filesystems or deviceless filesystems)
23
24e) Compounding (in progress) to reduce number of roundtrips, and also
25better optimize open to reduce redundant opens (using reference counts more).
26
27f) Finish inotify support so kde and gnome file list windows
28will autorefresh (partially complete by Asser). Needs minor kernel
29vfs change to support removing D_NOTIFY on a file.
30
31g) Add GUI tool to configure /proc/fs/cifs settings and for display of
32the CIFS statistics (started)
33
34h) implement support for security and trusted categories of xattrs
35(requires minor protocol extension) to enable better support for SELINUX
36
37i) Add support for tree connect contexts (see MS-SMB2) a new SMB3.1.1 protocol
38 feature (may be especially useful for virtualization).
39
40j) Create UID mapping facility so server UIDs can be mapped on a per
41mount or a per server basis to client UIDs or nobody if no mapping
42exists. Also better integration with winbind for resolving SID owners
43
44k) Add tools to take advantage of more smb3 specific ioctls and features
45
46l) encrypted file support
47
48m) improved stats gathering, tools (perhaps integration with nfsometer?)
49
50n) allow setting more NTFS/SMB3 file attributes remotely (currently limited to compressed
51file attribute via chflags) and improve user space tools for managing and
52viewing them.
53
54o) mount helper GUI (to simplify the various configuration options on mount)
55
56p) Add support for witness protocol (perhaps ioctl to cifs.ko from user space
57 tool listening on witness protocol RPC) to allow for notification of share
58 move, server failover, and server adapter changes. And also improve other
59 failover scenarios, e.g. when client knows multiple DFS entries point to
60 different servers, and the server we are connected to has gone down.
61
62q) Allow mount.cifs to be more verbose in reporting errors with dialect
63or unsupported feature errors.
64
65r) updating cifs documentation, and user guide.
66
67s) Addressing bugs found by running a broader set of xfstests in standard
68file system xfstest suite.
69
70t) split cifs and smb3 support into separate modules so legacy (and less
71secure) CIFS dialect can be disabled in environments that don't need it
72and simplify the code.
73
74u) Finish up SMB3.1.1 dialect support
75
76v) POSIX Extensions for SMB3.1.1
77
78KNOWN BUGS
79====================================
80See http://bugzilla.samba.org - search on product "CifsVFS" for
81current bug list. Also check http://bugzilla.kernel.org (Product = File System, Component = CIFS)
82
831) existing symbolic links (Windows reparse points) are recognized but
84can not be created remotely. They are implemented for Samba and those that
85support the CIFS Unix extensions, although earlier versions of Samba
86overly restrict the pathnames.
872) follow_link and readdir code does not follow dfs junctions
88but recognizes them
89
90Misc testing to do
91==================
921) check out max path names and max path name components against various server
93types. Try nested symlinks (8 deep). Return max path name in stat -f information
94
952) Improve xfstest's cifs enablement and adapt xfstests where needed to test
96cifs better
97
983) Additional performance testing and optimization using iozone and similar -
99there are some easy changes that can be done to parallelize sequential writes,
100and when signing is disabled to request larger read sizes (larger than
101negotiated size) and send larger write sizes to modern servers.
102
1034) More exhaustively test against less common servers