5 Version 2.14 December 21, 2018
7 A Partial List of Missing Features
8 ==================================
10 Contributions are welcome. There are plenty of opportunities
11 for visible, important contributions to this module. Here
12 is a partial list of the known problems and missing features:
14 a) SMB3 (and SMB3.1.1) missing optional features:
16 - multichannel (partially integrated), integration of multichannel with RDMA
17 - directory leases (improved metadata caching). Currently only implemented for root dir
18 - T10 copy offload ie "ODX" (copy chunk, and "Duplicate Extents" ioctl
19 currently the only two server side copy mechanisms supported)
21 b) improved sparse file support (fiemap and SEEK_HOLE are implemented
22 but additional features would be supportable by the protocol such
23 as FALLOC_FL_COLLAPSE_RANGE and FALLOC_FL_INSERT_RANGE)
25 c) Directory entry caching relies on a 1 second timer, rather than
26 using Directory Leases, currently only the root file handle is cached longer
27 by leveraging Directory Leases
29 d) quota support (needs minor kernel change since quota calls otherwise
30 won't make it to network filesystems or deviceless filesystems).
32 e) Additional use cases can be optimized to use "compounding" (e.g.
33 open/query/close and open/setinfo/close) to reduce the number of
34 roundtrips to the server and improve performance. Various cases
35 (stat, statfs, create, unlink, mkdir, xattrs) already have been improved by
36 using compounding but more can be done. In addition we could
37 significantly reduce redundant opens by using deferred close (with
38 handle caching leases) and better using reference counters on file
41 f) Finish inotify support so kde and gnome file list windows
42 will autorefresh (partially complete by Asser). Needs minor kernel
43 vfs change to support removing D_NOTIFY on a file.
45 g) Add GUI tool to configure /proc/fs/cifs settings and for display of
46 the CIFS statistics (started)
48 h) implement support for security and trusted categories of xattrs
49 (requires minor protocol extension) to enable better support for SELINUX
51 i) Add support for tree connect contexts (see MS-SMB2) a new SMB3.1.1 protocol
52 feature (may be especially useful for virtualization).
54 j) Create UID mapping facility so server UIDs can be mapped on a per
55 mount or a per server basis to client UIDs or nobody if no mapping
56 exists. Also better integration with winbind for resolving SID owners
58 k) Add tools to take advantage of more smb3 specific ioctls and features
59 (passthrough ioctl/fsctl is now implemented in cifs.ko to allow
60 sending various SMB3 fsctls and query info and set info calls
61 directly from user space) Add tools to make setting various non-POSIX
62 metadata attributes easier from tools (e.g. extending what was done
65 l) encrypted file support (currently the attribute showing the file is
66 encrypted on the server is reported, but changing the attribute is not
69 m) improved stats gathering tools (perhaps integration with nfsometer?)
70 to extend and make easier to use what is currently in /proc/fs/cifs/Stats
72 n) Add support for claims based ACLs ("DAC")
74 o) mount helper GUI (to simplify the various configuration options on mount)
76 p) Expand support for witness protocol to allow for notification of share
77 move, and server network adapter changes. Currently only notifications by
78 the witness protocol for server move is supported by the Linux client.
80 q) Allow mount.cifs to be more verbose in reporting errors with dialect
81 or unsupported feature errors. This would now be easier due to the
82 implementation of the new mount API.
84 r) updating cifs documentation, and user guide.
86 s) Addressing bugs found by running a broader set of xfstests in standard
87 file system xfstest suite.
89 t) split cifs and smb3 support into separate modules so legacy (and less
90 secure) CIFS dialect can be disabled in environments that don't need it
91 and simplify the code.
93 v) Additional testing of POSIX Extensions for SMB3.1.1
95 w) Add support for additional strong encryption types, and additional spnego
96 authentication mechanisms (see MS-SMB2). GCM-256 is now partially implemented.
98 x) Finish support for SMB3.1.1 compression
103 See https://bugzilla.samba.org - search on product "CifsVFS" for
104 current bug list. Also check http://bugzilla.kernel.org (Product = File System, Component = CIFS)
106 1) existing symbolic links (Windows reparse points) are recognized but
107 can not be created remotely. They are implemented for Samba and those that
108 support the CIFS Unix extensions, although earlier versions of Samba
109 overly restrict the pathnames.
110 2) follow_link and readdir code does not follow dfs junctions
115 1) check out max path names and max path name components against various server
116 types. Try nested symlinks (8 deep). Return max path name in stat -f information
118 2) Improve xfstest's cifs/smb3 enablement and adapt xfstests where needed to test
121 3) Additional performance testing and optimization using iozone and similar -
122 there are some easy changes that can be done to parallelize sequential writes,
123 and when signing is disabled to request larger read sizes (larger than
124 negotiated size) and send larger write sizes to modern servers.
126 4) More exhaustively test against less common servers
128 5) Continue to extend the smb3 "buildbot" which does automated xfstesting
129 against Windows, Samba and Azure currently - to add additional tests and
130 to allow the buildbot to execute the tests faster. The URL for the
131 buildbot is: http://smb3-test-rhel-75.southcentralus.cloudapp.azure.com
133 6) Address various coverity warnings (most are not bugs per-se, but
134 the more warnings are addressed, the easier it is to spot real
135 problems that static analyzers will point out in the future).