Merge tag 'docs-5.7' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "This has been a busy cycle for documentation work.

  Highlights include:

   - Lots of RST conversion work by Mauro, Daniel ALmeida, and others.
     Maybe someday we'll get to the end of this stuff...maybe...

   - Some organizational work to bring some order to the core-api
     manual.

   - Various new docs and additions to the existing documentation.

   - Typo fixes, warning fixes, ..."

* tag 'docs-5.7' of git://git.lwn.net/linux: (123 commits)
  Documentation: x86: exception-tables: document CONFIG_BUILDTIME_TABLE_SORT
  MAINTAINERS: adjust to filesystem doc ReST conversion
  docs: deprecated.rst: Add BUG()-family
  doc: zh_CN: add translation for virtiofs
  doc: zh_CN: index files in filesystems subdirectory
  docs: locking: Drop :c:func: throughout
  docs: locking: Add 'need' to hardirq section
  docs: conf.py: avoid thousands of duplicate label warning on Sphinx
  docs: prevent warnings due to autosectionlabel
  docs: fix reference to core-api/namespaces.rst
  docs: fix pointers to io-mapping.rst and io_ordering.rst files
  Documentation: Better document the softlockup_panic sysctl
  docs: hw-vuln: tsx_async_abort.rst: get rid of an unused ref
  docs: perf: imx-ddr.rst: get rid of a warning
  docs: filesystems: fuse.rst: supress a Sphinx warning
  docs: translations: it: avoid duplicate refs at programming-language.rst
  docs: driver.rst: supress two ReSt warnings
  docs: trace: events.rst: convert some new stuff to ReST format
  Documentation: Add io_ordering.rst to driver-api manual
  Documentation: Add io-mapping.rst to driver-api manual
  ...

1 files changed, 256 insertions, 0 deletions

diff --git a/Documentation/filesystems/nfs/nfs41-server.rst b/Documentation/filesystems/nfs/nfs41-server.rst
new file mode 100644
index 000000000000..16b5f02f81c3
--- /dev/null
+++ b/Documentation/filesystems/nfs/nfs41-server.rst
@@ -0,0 +1,256 @@
+=============================
+NFSv4.1 Server Implementation
+=============================
+
+Server support for minorversion 1 can be controlled using the
+/proc/fs/nfsd/versions control file.  The string output returned
+by reading this file will contain either "+4.1" or "-4.1"
+correspondingly.
+
+Currently, server support for minorversion 1 is enabled by default.
+It can be disabled at run time by writing the string "-4.1" to
+the /proc/fs/nfsd/versions control file.  Note that to write this
+control file, the nfsd service must be taken down.  You can use rpc.nfsd
+for this; see rpc.nfsd(8).
+
+(Warning: older servers will interpret "+4.1" and "-4.1" as "+4" and
+"-4", respectively.  Therefore, code meant to work on both new and old
+kernels must turn 4.1 on or off *before* turning support for version 4
+on or off; rpc.nfsd does this correctly.)
+
+The NFSv4 minorversion 1 (NFSv4.1) implementation in nfsd is based
+on RFC 5661.
+
+From the many new features in NFSv4.1 the current implementation
+focuses on the mandatory-to-implement NFSv4.1 Sessions, providing
+"exactly once" semantics and better control and throttling of the
+resources allocated for each client.
+
+The table below, taken from the NFSv4.1 document, lists
+the operations that are mandatory to implement (REQ), optional
+(OPT), and NFSv4.0 operations that are required not to implement (MNI)
+in minor version 1.  The first column indicates the operations that
+are not supported yet by the linux server implementation.
+
+The OPTIONAL features identified and their abbreviations are as follows:
+
+- **pNFS**	Parallel NFS
+- **FDELG**	File Delegations
+- **DDELG**	Directory Delegations
+
+The following abbreviations indicate the linux server implementation status.
+
+- **I**	Implemented NFSv4.1 operations.
+- **NS**	Not Supported.
+- **NS\***	Unimplemented optional feature.
+
+Operations
+==========
+
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| Implementation status | Operation            | REQ,REC, OPT or NMI | Feature (REQ, REC or OPT) | Definition     |
++=======================+======================+=====================+===========================+================+
+|                       | ACCESS               | REQ                 |                           | Section 18.1   |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| I                     | BACKCHANNEL_CTL      | REQ                 |                           | Section 18.33  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| I                     | BIND_CONN_TO_SESSION | REQ                 |                           | Section 18.34  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | CLOSE                | REQ                 |                           | Section 18.2   |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | COMMIT               | REQ                 |                           | Section 18.3   |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | CREATE               | REQ                 |                           | Section 18.4   |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| I                     | CREATE_SESSION       | REQ                 |                           | Section 18.36  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| NS*                   | DELEGPURGE           | OPT                 | FDELG (REQ)               | Section 18.5   |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | DELEGRETURN          | OPT                 | FDELG,                    | Section 18.6   |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       |                      |                     | DDELG, pNFS               |                |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       |                      |                     | (REQ)                     |                |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| I                     | DESTROY_CLIENTID     | REQ                 |                           | Section 18.50  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| I                     | DESTROY_SESSION      | REQ                 |                           | Section 18.37  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| I                     | EXCHANGE_ID          | REQ                 |                           | Section 18.35  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| I                     | FREE_STATEID         | REQ                 |                           | Section 18.38  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | GETATTR              | REQ                 |                           | Section 18.7   |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| I                     | GETDEVICEINFO        | OPT                 | pNFS (REQ)                | Section 18.40  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| NS*                   | GETDEVICELIST        | OPT                 | pNFS (OPT)                | Section 18.41  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | GETFH                | REQ                 |                           | Section 18.8   |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| NS*                   | GET_DIR_DELEGATION   | OPT                 | DDELG (REQ)               | Section 18.39  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| I                     | LAYOUTCOMMIT         | OPT                 | pNFS (REQ)                | Section 18.42  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| I                     | LAYOUTGET            | OPT                 | pNFS (REQ)                | Section 18.43  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| I                     | LAYOUTRETURN         | OPT                 | pNFS (REQ)                | Section 18.44  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | LINK                 | OPT                 |                           | Section 18.9   |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | LOCK                 | REQ                 |                           | Section 18.10  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | LOCKT                | REQ                 |                           | Section 18.11  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | LOCKU                | REQ                 |                           | Section 18.12  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | LOOKUP               | REQ                 |                           | Section 18.13  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | LOOKUPP              | REQ                 |                           | Section 18.14  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | NVERIFY              | REQ                 |                           | Section 18.15  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | OPEN                 | REQ                 |                           | Section 18.16  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| NS*                   | OPENATTR             | OPT                 |                           | Section 18.17  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | OPEN_CONFIRM         | MNI                 |                           | N/A            |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | OPEN_DOWNGRADE       | REQ                 |                           | Section 18.18  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | PUTFH                | REQ                 |                           | Section 18.19  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | PUTPUBFH             | REQ                 |                           | Section 18.20  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | PUTROOTFH            | REQ                 |                           | Section 18.21  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | READ                 | REQ                 |                           | Section 18.22  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | READDIR              | REQ                 |                           | Section 18.23  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | READLINK             | OPT                 |                           | Section 18.24  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | RECLAIM_COMPLETE     | REQ                 |                           | Section 18.51  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | RELEASE_LOCKOWNER    | MNI                 |                           | N/A            |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | REMOVE               | REQ                 |                           | Section 18.25  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | RENAME               | REQ                 |                           | Section 18.26  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | RENEW                | MNI                 |                           | N/A            |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | RESTOREFH            | REQ                 |                           | Section 18.27  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | SAVEFH               | REQ                 |                           | Section 18.28  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+|                       | SECINFO              | REQ                 |                           | Section 18.29  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| 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  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+| 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  |
++-----------------------+----------------------+---------------------+---------------------------+----------------+
+
+
+Callback Operations
+===================
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+| Implementation status | Operation               | REQ,REC, OPT or NMI | Feature (REQ, REC or OPT) | Definition    |
++=======================+=========================+=====================+===========================+===============+
+|                       | CB_GETATTR              | OPT                 | FDELG (REQ)               | Section 20.1  |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+| I                     | CB_LAYOUTRECALL         | OPT                 | pNFS (REQ)                | Section 20.3  |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+| NS*                   | CB_NOTIFY               | OPT                 | DDELG (REQ)               | Section 20.4  |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+| NS*                   | CB_NOTIFY_DEVICEID      | OPT                 | pNFS (OPT)                | Section 20.12 |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+| NS*                   | CB_NOTIFY_LOCK          | OPT                 |                           | Section 20.11 |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+| NS*                   | CB_PUSH_DELEG           | OPT                 | FDELG (OPT)               | Section 20.5  |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+|                       | CB_RECALL               | OPT                 | FDELG,                    | Section 20.2  |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+|                       |                         |                     | DDELG, pNFS               |               |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+|                       |                         |                     | (REQ)                     |               |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+| NS*                   | CB_RECALL_ANY           | OPT                 | FDELG,                    | Section 20.6  |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+|                       |                         |                     | DDELG, pNFS               |               |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+|                       |                         |                     | (REQ)                     |               |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+| NS                    | CB_RECALL_SLOT          | REQ                 |                           | Section 20.8  |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+| NS*                   | CB_RECALLABLE_OBJ_AVAIL | OPT                 | DDELG, pNFS               | Section 20.7  |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+|                       |                         |                     | (REQ)                     |               |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+| I                     | CB_SEQUENCE             | OPT                 | FDELG,                    | Section 20.9  |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+|                       |                         |                     | DDELG, pNFS               |               |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+|                       |                         |                     | (REQ)                     |               |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+| NS*                   | CB_WANTS_CANCELLED      | OPT                 | FDELG,                    | Section 20.10 |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+|                       |                         |                     | DDELG, pNFS               |               |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+|                       |                         |                     | (REQ)                     |               |
++-----------------------+-------------------------+---------------------+---------------------------+---------------+
+
+
+Implementation notes:
+=====================
+
+SSV:
+  The spec claims this is mandatory, but we don't actually know of any
+  implementations, so we're ignoring it for now.  The server returns
+  NFS4ERR_ENCR_ALG_UNSUPP on EXCHANGE_ID, which should be future-proof.
+
+GSS on the backchannel:
+  Again, theoretically required but not widely implemented (in
+  particular, the current Linux client doesn't request it).  We return
+  NFS4ERR_ENCR_ALG_UNSUPP on CREATE_SESSION.
+
+DELEGPURGE:
+  mandatory only for servers that support CLAIM_DELEGATE_PREV and/or
+  CLAIM_DELEG_PREV_FH (which allows clients to keep delegations that
+  persist across client reboots).  Thus we need not implement this for
+  now.
+
+EXCHANGE_ID:
+  implementation ids are ignored
+
+CREATE_SESSION:
+  backchannel attributes are ignored
+
+SEQUENCE:
+  no support for dynamic slot table renegotiation (optional)
+
+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
+  fail to live up to the promise we made in CREATE_SESSION fore channel
+  negotiation.
+
+See also http://wiki.linux-nfs.org/wiki/index.php/Server_4.0_and_4.1_issues.