About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Documentation / filesystems / nfs / nfs41-server.txt




Custom Search

Based on kernel version 4.1. Page generated on 2015-06-28 12:12 EST.

1	NFSv4.1 Server Implementation
2	
3	Server support for minorversion 1 can be controlled using the
4	/proc/fs/nfsd/versions control file.  The string output returned
5	by reading this file will contain either "+4.1" or "-4.1"
6	correspondingly.
7	
8	Currently, server support for minorversion 1 is enabled by default.
9	It can be disabled at run time by writing the string "-4.1" to
10	the /proc/fs/nfsd/versions control file.  Note that to write this
11	control file, the nfsd service must be taken down.  You can use rpc.nfsd
12	for this; see rpc.nfsd(8).
13	
14	(Warning: older servers will interpret "+4.1" and "-4.1" as "+4" and
15	"-4", respectively.  Therefore, code meant to work on both new and old
16	kernels must turn 4.1 on or off *before* turning support for version 4
17	on or off; rpc.nfsd does this correctly.)
18	
19	The NFSv4 minorversion 1 (NFSv4.1) implementation in nfsd is based
20	on RFC 5661.
21	
22	From the many new features in NFSv4.1 the current implementation
23	focuses on the mandatory-to-implement NFSv4.1 Sessions, providing
24	"exactly once" semantics and better control and throttling of the
25	resources allocated for each client.
26	
27	The table below, taken from the NFSv4.1 document, lists
28	the operations that are mandatory to implement (REQ), optional
29	(OPT), and NFSv4.0 operations that are required not to implement (MNI)
30	in minor version 1.  The first column indicates the operations that
31	are not supported yet by the linux server implementation.
32	
33	The OPTIONAL features identified and their abbreviations are as follows:
34		pNFS	Parallel NFS
35		FDELG	File Delegations
36		DDELG	Directory Delegations
37	
38	The following abbreviations indicate the linux server implementation status.
39		I	Implemented NFSv4.1 operations.
40		NS	Not Supported.
41		NS*	Unimplemented optional feature.
42	
43	Operations
44	
45	   +----------------------+------------+--------------+----------------+
46	   | Operation            | REQ, REC,  | Feature      | Definition     |
47	   |                      | OPT, or    | (REQ, REC,   |                |
48	   |                      | MNI        | or OPT)      |                |
49	   +----------------------+------------+--------------+----------------+
50	   | ACCESS               | REQ        |              | Section 18.1   |
51	I  | BACKCHANNEL_CTL      | REQ        |              | Section 18.33  |
52	I  | BIND_CONN_TO_SESSION | REQ        |              | Section 18.34  |
53	   | CLOSE                | REQ        |              | Section 18.2   |
54	   | COMMIT               | REQ        |              | Section 18.3   |
55	   | CREATE               | REQ        |              | Section 18.4   |
56	I  | CREATE_SESSION       | REQ        |              | Section 18.36  |
57	NS*| DELEGPURGE           | OPT        | FDELG (REQ)  | Section 18.5   |
58	   | DELEGRETURN          | OPT        | FDELG,       | Section 18.6   |
59	   |                      |            | DDELG, pNFS  |                |
60	   |                      |            | (REQ)        |                |
61	I  | DESTROY_CLIENTID     | REQ        |              | Section 18.50  |
62	I  | DESTROY_SESSION      | REQ        |              | Section 18.37  |
63	I  | EXCHANGE_ID          | REQ        |              | Section 18.35  |
64	I  | FREE_STATEID         | REQ        |              | Section 18.38  |
65	   | GETATTR              | REQ        |              | Section 18.7   |
66	I  | GETDEVICEINFO        | OPT        | pNFS (REQ)   | Section 18.40  |
67	NS*| GETDEVICELIST        | OPT        | pNFS (OPT)   | Section 18.41  |
68	   | GETFH                | REQ        |              | Section 18.8   |
69	NS*| GET_DIR_DELEGATION   | OPT        | DDELG (REQ)  | Section 18.39  |
70	I  | LAYOUTCOMMIT         | OPT        | pNFS (REQ)   | Section 18.42  |
71	I  | LAYOUTGET            | OPT        | pNFS (REQ)   | Section 18.43  |
72	I  | LAYOUTRETURN         | OPT        | pNFS (REQ)   | Section 18.44  |
73	   | LINK                 | OPT        |              | Section 18.9   |
74	   | LOCK                 | REQ        |              | Section 18.10  |
75	   | LOCKT                | REQ        |              | Section 18.11  |
76	   | LOCKU                | REQ        |              | Section 18.12  |
77	   | LOOKUP               | REQ        |              | Section 18.13  |
78	   | LOOKUPP              | REQ        |              | Section 18.14  |
79	   | NVERIFY              | REQ        |              | Section 18.15  |
80	   | OPEN                 | REQ        |              | Section 18.16  |
81	NS*| OPENATTR             | OPT        |              | Section 18.17  |
82	   | OPEN_CONFIRM         | MNI        |              | N/A            |
83	   | OPEN_DOWNGRADE       | REQ        |              | Section 18.18  |
84	   | PUTFH                | REQ        |              | Section 18.19  |
85	   | PUTPUBFH             | REQ        |              | Section 18.20  |
86	   | PUTROOTFH            | REQ        |              | Section 18.21  |
87	   | READ                 | REQ        |              | Section 18.22  |
88	   | READDIR              | REQ        |              | Section 18.23  |
89	   | READLINK             | OPT        |              | Section 18.24  |
90	   | RECLAIM_COMPLETE     | REQ        |              | Section 18.51  |
91	   | RELEASE_LOCKOWNER    | MNI        |              | N/A            |
92	   | REMOVE               | REQ        |              | Section 18.25  |
93	   | RENAME               | REQ        |              | Section 18.26  |
94	   | RENEW                | MNI        |              | N/A            |
95	   | RESTOREFH            | REQ        |              | Section 18.27  |
96	   | SAVEFH               | REQ        |              | Section 18.28  |
97	   | SECINFO              | REQ        |              | Section 18.29  |
98	I  | SECINFO_NO_NAME      | REC        | pNFS files   | Section 18.45, |
99	   |                      |            | layout (REQ) | Section 13.12  |
100	I  | SEQUENCE             | REQ        |              | Section 18.46  |
101	   | SETATTR              | REQ        |              | Section 18.30  |
102	   | SETCLIENTID          | MNI        |              | N/A            |
103	   | SETCLIENTID_CONFIRM  | MNI        |              | N/A            |
104	NS | SET_SSV              | REQ        |              | Section 18.47  |
105	I  | TEST_STATEID         | REQ        |              | Section 18.48  |
106	   | VERIFY               | REQ        |              | Section 18.31  |
107	NS*| WANT_DELEGATION      | OPT        | FDELG (OPT)  | Section 18.49  |
108	   | WRITE                | REQ        |              | Section 18.32  |
109	
110	Callback Operations
111	
112	   +-------------------------+-----------+-------------+---------------+
113	   | Operation               | REQ, REC, | Feature     | Definition    |
114	   |                         | OPT, or   | (REQ, REC,  |               |
115	   |                         | MNI       | or OPT)     |               |
116	   +-------------------------+-----------+-------------+---------------+
117	   | CB_GETATTR              | OPT       | FDELG (REQ) | Section 20.1  |
118	I  | CB_LAYOUTRECALL         | OPT       | pNFS (REQ)  | Section 20.3  |
119	NS*| CB_NOTIFY               | OPT       | DDELG (REQ) | Section 20.4  |
120	NS*| CB_NOTIFY_DEVICEID      | OPT       | pNFS (OPT)  | Section 20.12 |
121	NS*| CB_NOTIFY_LOCK          | OPT       |             | Section 20.11 |
122	NS*| CB_PUSH_DELEG           | OPT       | FDELG (OPT) | Section 20.5  |
123	   | CB_RECALL               | OPT       | FDELG,      | Section 20.2  |
124	   |                         |           | DDELG, pNFS |               |
125	   |                         |           | (REQ)       |               |
126	NS*| CB_RECALL_ANY           | OPT       | FDELG,      | Section 20.6  |
127	   |                         |           | DDELG, pNFS |               |
128	   |                         |           | (REQ)       |               |
129	NS | CB_RECALL_SLOT          | REQ       |             | Section 20.8  |
130	NS*| CB_RECALLABLE_OBJ_AVAIL | OPT       | DDELG, pNFS | Section 20.7  |
131	   |                         |           | (REQ)       |               |
132	I  | CB_SEQUENCE             | OPT       | FDELG,      | Section 20.9  |
133	   |                         |           | DDELG, pNFS |               |
134	   |                         |           | (REQ)       |               |
135	NS*| CB_WANTS_CANCELLED      | OPT       | FDELG,      | Section 20.10 |
136	   |                         |           | DDELG, pNFS |               |
137	   |                         |           | (REQ)       |               |
138	   +-------------------------+-----------+-------------+---------------+
139	
140	Implementation notes:
141	
142	SSV:
143	* The spec claims this is mandatory, but we don't actually know of any
144	  implementations, so we're ignoring it for now.  The server returns
145	  NFS4ERR_ENCR_ALG_UNSUPP on EXCHANGE_ID, which should be future-proof.
146	
147	GSS on the backchannel:
148	* Again, theoretically required but not widely implemented (in
149	  particular, the current Linux client doesn't request it).  We return
150	  NFS4ERR_ENCR_ALG_UNSUPP on CREATE_SESSION.
151	
152	DELEGPURGE:
153	* mandatory only for servers that support CLAIM_DELEGATE_PREV and/or
154	  CLAIM_DELEG_PREV_FH (which allows clients to keep delegations that
155	  persist across client reboots).  Thus we need not implement this for
156	  now.
157	
158	EXCHANGE_ID:
159	* implementation ids are ignored
160	
161	CREATE_SESSION:
162	* backchannel attributes are ignored
163	
164	SEQUENCE:
165	* no support for dynamic slot table renegotiation (optional)
166	
167	Nonstandard compound limitations:
168	* No support for a sessions fore channel RPC compound that requires both a
169	  ca_maxrequestsize request and a ca_maxresponsesize reply, so we may
170	  fail to live up to the promise we made in CREATE_SESSION fore channel
171	  negotiation.
172	
173	See also http://wiki.linux-nfs.org/wiki/index.php/Server_4.0_and_4.1_issues.
Hide Line Numbers
About Kernel Documentation Linux Kernel Contact Linux Resources Linux Blog

Information is copyright its respective author. All material is available from the Linux Kernel Source distributed under a GPL License. This page is provided as a free service by mjmwired.net.