Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw

* git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw:
  [GFS2] Fix GFS2's use of do_div() in its quota calculations
  [GFS2] Remove unused declaration
  [GFS2] Remove support for unused and pointless flag
  [GFS2] Replace rgrp "recent list" with mru list
  [GFS2] Allow local DF locks when holding a cached EX glock
  [GFS2] Fix delayed demote race
  [GFS2] don't call permission()
  [GFS2] Fix module building
  [GFS2] Glock documentation
  [GFS2] Remove all_list from lock_dlm
  [GFS2] Remove obsolete conversion deadlock avoidance code
  [GFS2] Remove remote lock dropping code
  [GFS2] kernel panic mounting volume
  [GFS2] Revise readpage locking
  [GFS2] Fix ordering of args for list_add
  [GFS2] trivial sparse lock annotations
  [GFS2] No lock_nolock
  [GFS2] Fix ordering bug in lock_dlm
  [GFS2] Clean up the glock core

Documentation/filesystems/gfs2-glocks.txt

@@ -0,0 +1,114 @@
+                   Glock internal locking rules
+                  ------------------------------
+
+This documents the basic principles of the glock state machine
+internals. Each glock (struct gfs2_glock in fs/gfs2/incore.h)
+has two main (internal) locks:
+
+ 1. A spinlock (gl_spin) which protects the internal state such
+    as gl_state, gl_target and the list of holders (gl_holders)
+ 2. A non-blocking bit lock, GLF_LOCK, which is used to prevent other
+    threads from making calls to the DLM, etc. at the same time. If a
+    thread takes this lock, it must then call run_queue (usually via the
+    workqueue) when it releases it in order to ensure any pending tasks
+    are completed.
+
+The gl_holders list contains all the queued lock requests (not
+just the holders) associated with the glock. If there are any
+held locks, then they will be contiguous entries at the head
+of the list. Locks are granted in strictly the order that they
+are queued, except for those marked LM_FLAG_PRIORITY which are
+used only during recovery, and even then only for journal locks.
+
+There are three lock states that users of the glock layer can request,
+namely shared (SH), deferred (DF) and exclusive (EX). Those translate
+to the following DLM lock modes:
+
+Glock mode    | DLM lock mode
+------------------------------
+    UN        |    IV/NL  Unlocked (no DLM lock associated with glock) or NL
+    SH        |    PR     (Protected read)
+    DF        |    CW     (Concurrent write)
+    EX        |    EX     (Exclusive)
+
+Thus DF is basically a shared mode which is incompatible with the "normal"
+shared lock mode, SH. In GFS2 the DF mode is used exclusively for direct I/O
+operations. The glocks are basically a lock plus some routines which deal
+with cache management. The following rules apply for the cache:
+
+Glock mode   |  Cache data | Cache Metadata | Dirty Data | Dirty Metadata
+--------------------------------------------------------------------------
+    UN       |     No      |       No       |     No     |      No
+    SH       |     Yes     |       Yes      |     No     |      No
+    DF       |     No      |       Yes      |     No     |      No
+    EX       |     Yes     |       Yes      |     Yes    |      Yes
+
+These rules are implemented using the various glock operations which
+are defined for each type of glock. Not all types of glocks use
+all the modes. Only inode glocks use the DF mode for example.
+
+Table of glock operations and per type constants:
+
+Field            | Purpose
+----------------------------------------------------------------------------
+go_xmote_th      | Called before remote state change (e.g. to sync dirty data)
+go_xmote_bh      | Called after remote state change (e.g. to refill cache)
+go_inval         | Called if remote state change requires invalidating the cache
+go_demote_ok     | Returns boolean value of whether its ok to demote a glock
+                 | (e.g. checks timeout, and that there is no cached data)
+go_lock          | Called for the first local holder of a lock
+go_unlock        | Called on the final local unlock of a lock
+go_dump          | Called to print content of object for debugfs file, or on
+                 | error to dump glock to the log.
+go_type;         | The type of the glock, LM_TYPE_.....
+go_min_hold_time | The minimum hold time
+
+The minimum hold time for each lock is the time after a remote lock
+grant for which we ignore remote demote requests. This is in order to
+prevent a situation where locks are being bounced around the cluster
+from node to node with none of the nodes making any progress. This
+tends to show up most with shared mmaped files which are being written
+to by multiple nodes. By delaying the demotion in response to a
+remote callback, that gives the userspace program time to make
+some progress before the pages are unmapped.
+
+There is a plan to try and remove the go_lock and go_unlock callbacks
+if possible, in order to try and speed up the fast path though the locking.
+Also, eventually we hope to make the glock "EX" mode locally shared
+such that any local locking will be done with the i_mutex as required
+rather than via the glock.
+
+Locking rules for glock operations:
+
+Operation     |  GLF_LOCK bit lock held |  gl_spin spinlock held
+-----------------------------------------------------------------
+go_xmote_th   |       Yes               |       No
+go_xmote_bh   |       Yes               |       No
+go_inval      |       Yes               |       No
+go_demote_ok  |       Sometimes         |       Yes
+go_lock       |       Yes               |       No
+go_unlock     |       Yes               |       No
+go_dump       |       Sometimes         |       Yes
+
+N.B. Operations must not drop either the bit lock or the spinlock
+if its held on entry. go_dump and do_demote_ok must never block.
+Note that go_dump will only be called if the glock's state
+indicates that it is caching uptodate data.
+
+Glock locking order within GFS2:
+
+ 1. i_mutex (if required)
+ 2. Rename glock (for rename only)
+ 3. Inode glock(s)
+    (Parents before children, inodes at "same level" with same parent in
+     lock number order)
+ 4. Rgrp glock(s) (for (de)allocation operations)
+ 5. Transaction glock (via gfs2_trans_begin) for non-read operations
+ 6. Page lock  (always last, very important!)
+
+There are two glocks per inode. One deals with access to the inode
+itself (locking order as above), and the other, known as the iopen
+glock is used in conjunction with the i_nlink field in the inode to
+determine the lifetime of the inode in question. Locking of inodes
+is on a per-inode basis. Locking of rgrps is on a per rgrp basis.
+

fs/gfs2/Kconfig

@@ -14,23 +14,11 @@ config GFS2_FS
 	  GFS is perfect consistency -- changes made to the filesystem on one
 	  machine show up immediately on all other machines in the cluster.
 
-	  To use the GFS2 filesystem, you will need to enable one or more of
-	  the below locking modules. Documentation and utilities for GFS2 can
+	  To use the GFS2 filesystem in a cluster, you will need to enable
+	  the locking module below. Documentation and utilities for GFS2 can
 	  be found here: http://sources.redhat.com/cluster
 
-config GFS2_FS_LOCKING_NOLOCK
-	tristate "GFS2 \"nolock\" locking module"
-	depends on GFS2_FS
-	help
-	  Single node locking module for GFS2.
-
-	  Use this module if you want to use GFS2 on a single node without
-	  its clustering features. You can still take advantage of the
-	  large file support, and upgrade to running a full cluster later on
-	  if required.
-
-	  If you will only be using GFS2 in cluster mode, you do not need this
-	  module.
+	  The "nolock" lock module is now built in to GFS2 by default.
 
 config GFS2_FS_LOCKING_DLM
 	tristate "GFS2 DLM locking module"

fs/gfs2/Makefile

@@ -5,6 +5,5 @@ gfs2-y := acl.o bmap.o daemon.o dir.o eaops.o eattr.o glock.o \
 	ops_fstype.o ops_inode.o ops_super.o quota.o \
 	recovery.o rgrp.o super.o sys.o trans.o util.o
 
-obj-$(CONFIG_GFS2_FS_LOCKING_NOLOCK) += locking/nolock/
 obj-$(CONFIG_GFS2_FS_LOCKING_DLM) += locking/dlm/
 

fs/gfs2/gfs2.h

@@ -15,11 +15,6 @@ enum {
 	CREATE = 1,
 };
 
-enum {
-	NO_WAIT = 0,
-	WAIT = 1,
-};
-
 enum {
 	NO_FORCE = 0,
 	FORCE = 1,