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Commit c46556c6 authored by J. Bruce Fields's avatar J. Bruce Fields
Browse files

nfsd4: update nfsv4.1 implementation notes 



Update documentation to reflect recent progress.

Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent 1091006c

Documentation/filesystems/nfs/nfs41-server.txt

+10 −23
Original line number Diff line number Diff line
@@ -39,27 +39,17 @@ interoperability problems with future clients. Known issues: 
	  from a linux client are possible, but we aren't really

	  conformant with the spec (for example, we don't use kerberos

	  on the backchannel correctly).

	- no trunking support: no clients currently take advantage of

	  trunking, but this is a mandatory feature, and its use is

	  recommended to clients in a number of places.  (E.g. to ensure

	  timely renewal in case an existing connection's retry timeouts

	  have gotten too long; see section 8.3 of the RFC.)

	  Therefore, lack of this feature may cause future clients to

	  fail.

	- Incomplete backchannel support: incomplete backchannel gss

	  support and no support for BACKCHANNEL_CTL mean that

	  callbacks (hence delegations and layouts) may not be

	  available and clients confused by the incomplete

	  implementation may fail.

	- Server reboot recovery is unsupported; if the server reboots,

	  clients may fail.

	- We do not support SSV, which provides security for shared

	  client-server state (thus preventing unauthorized tampering

	  with locks and opens, for example).  It is mandatory for

	  servers to support this, though no clients use it yet.

	- Mandatory operations which we do not support, such as

	  DESTROY_CLIENTID, FREE_STATEID, SECINFO_NO_NAME, and

	  TEST_STATEID, are not currently used by clients, but will be

	  DESTROY_CLIENTID, are not currently used by clients, but will be

	  (and the spec recommends their uses in common cases), and

	  clients should not be expected to know how to recover from the

	  case where they are not supported.  This will eventually cause
@@ -69,8 +59,9 @@ In addition, some limitations are inherited from the current NFSv4 
implementation:



	- Incomplete delegation enforcement: if a file is renamed or

	  unlinked, a client holding a delegation may continue to

	  indefinitely allow opens of the file under the old name.

	  unlinked by a local process, a client holding a delegation may

	  continue to indefinitely allow opens of the file under the old

	  name.



The table below, taken from the NFSv4.1 document, lists

the operations that are mandatory to implement (REQ), optional
@@ -99,7 +90,7 @@ Operations 
   +----------------------+------------+--------------+----------------+

   | ACCESS               | REQ        |              | Section 18.1   |

NS | BACKCHANNEL_CTL      | REQ        |              | Section 18.33  |

NS | BIND_CONN_TO_SESSION | REQ        |              | Section 18.34  |

I  | BIND_CONN_TO_SESSION | REQ        |              | Section 18.34  |

   | CLOSE                | REQ        |              | Section 18.2   |

   | COMMIT               | REQ        |              | Section 18.3   |

   | CREATE               | REQ        |              | Section 18.4   |
@@ -111,7 +102,7 @@ NS*| DELEGPURGE | OPT | FDELG (REQ) | Section 18.5 | 
NS | DESTROY_CLIENTID     | REQ        |              | Section 18.50  |

I  | DESTROY_SESSION      | REQ        |              | Section 18.37  |

I  | EXCHANGE_ID          | REQ        |              | Section 18.35  |

NS | FREE_STATEID         | REQ        |              | Section 18.38  |

I  | FREE_STATEID         | REQ        |              | Section 18.38  |

   | GETATTR              | REQ        |              | Section 18.7   |

P  | GETDEVICEINFO        | OPT        | pNFS (REQ)   | Section 18.40  |

P  | GETDEVICELIST        | OPT        | pNFS (OPT)   | Section 18.41  |
@@ -145,14 +136,14 @@ NS*| OPENATTR | OPT | | Section 18.17 | 
   | RESTOREFH            | REQ        |              | Section 18.27  |

   | SAVEFH               | REQ        |              | Section 18.28  |

   | SECINFO              | REQ        |              | Section 18.29  |

NS | SECINFO_NO_NAME      | REC        | pNFS files   | Section 18.45, |

I  | SECINFO_NO_NAME      | REC        | pNFS files   | Section 18.45, |

   |                      |            | layout (REQ) | Section 13.12  |

I  | SEQUENCE             | REQ        |              | Section 18.46  |

   | SETATTR              | REQ        |              | Section 18.30  |

   | SETCLIENTID          | MNI        |              | N/A            |

   | SETCLIENTID_CONFIRM  | MNI        |              | N/A            |

NS | SET_SSV              | REQ        |              | Section 18.47  |

NS | TEST_STATEID         | REQ        |              | Section 18.48  |

I  | TEST_STATEID         | REQ        |              | Section 18.48  |

   | VERIFY               | REQ        |              | Section 18.31  |

NS*| WANT_DELEGATION      | OPT        | FDELG (OPT)  | Section 18.49  |

   | WRITE                | REQ        |              | Section 18.32  |
@@ -206,12 +197,6 @@ CREATE_SESSION: 
SEQUENCE:

* no support for dynamic slot table renegotiation (optional)



nfsv4.1 COMPOUND rules:

The following cases aren't supported yet:

* Enforcing of NFS4ERR_NOT_ONLY_OP for: BIND_CONN_TO_SESSION, CREATE_SESSION,

  DESTROY_CLIENTID, DESTROY_SESSION, EXCHANGE_ID.

* DESTROY_SESSION MUST be the final operation in the COMPOUND request.



Nonstandard compound limitations:

* No support for a sessions fore channel RPC compound that requires both a

  ca_maxrequestsize request and a ca_maxresponsesize reply, so we may
@@ -219,3 +204,5 @@ Nonstandard compound limitations: 
  negotiation.

* No more than one IO operation (read, write, readdir) allowed per

  compound.



See also http://wiki.linux-nfs.org/wiki/index.php/Server_4.0_and_4.1_issues.