GFS2: Merge lock_dlm module into GFS2

This is the big patch that I've been working on for some time
now. There are many reasons for wanting to make this change
such as:
 o Reducing overhead by eliminating duplicated fields between structures
 o Simplifcation of the code (reduces the code size by a fair bit)
 o The locking interface is now the DLM interface itself as proposed
   some time ago.
 o Fewer lookups of glocks when processing replies from the DLM
 o Fewer memory allocations/deallocations for each glock
 o Scope to do further optimisations in the future (but this patch is
   more than big enough for now!)

Please note that (a) this patch relates to the lock_dlm module and
not the DLM itself, that is still a separate module; and (b) that
we retain the ability to build GFS2 as a standalone single node
filesystem with out requiring the DLM.

This patch needs a lot of testing, hence my keeping it I restarted
my -git tree after the last merge window. That way, this has the maximum
exposure before its merged. This is (modulo a few minor bug fixes) the
same patch that I've been posting on and off the the last three months
and its passed a number of different tests so far.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 0 insertions, 314 deletions

diff --git a/fs/gfs2/locking.c b/fs/gfs2/locking.c
deleted file mode 100644
index d3657bc7938ae..0000000000000
--- a/fs/gfs2/locking.c
+++ /dev/null
@@ -1,314 +0,0 @@
-/*
- * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
- * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
- *
- * This copyrighted material is made available to anyone wishing to use,
- * modify, copy, or redistribute it subject to the terms and conditions
- * of the GNU General Public License version 2.
- */
-
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/string.h>
-#include <linux/slab.h>
-#include <linux/wait.h>
-#include <linux/sched.h>
-#include <linux/kmod.h>
-#include <linux/fs.h>
-#include <linux/delay.h>
-#include <linux/lm_interface.h>
-
-struct lmh_wrapper {
-	struct list_head lw_list;
-	const struct lm_lockops *lw_ops;
-};
-
-struct nolock_lockspace {
-	unsigned int nl_lvb_size;
-};
-
-/**
- * nolock_get_lock - get a lm_lock_t given a descripton of the lock
- * @lockspace: the lockspace the lock lives in
- * @name: the name of the lock
- * @lockp: return the lm_lock_t here
- *
- * Returns: 0 on success, -EXXX on failure
- */
-
-static int nolock_get_lock(void *lockspace, struct lm_lockname *name,
-                           void **lockp)
-{
-        *lockp = lockspace;
-        return 0;
-}
-
-/**
- * nolock_put_lock - get rid of a lock structure
- * @lock: the lock to throw away
- *
- */
-
-static void nolock_put_lock(void *lock)
-{
-}
-
-/**
- * nolock_hold_lvb - hold on to a lock value block
- * @lock: the lock the LVB is associated with
- * @lvbp: return the lm_lvb_t here
- *
- * Returns: 0 on success, -EXXX on failure
- */
-
-static int nolock_hold_lvb(void *lock, char **lvbp)
-{
-	struct nolock_lockspace *nl = lock;
-	int error = 0;
-
-	*lvbp = kzalloc(nl->nl_lvb_size, GFP_KERNEL);
-	if (!*lvbp)
-		error = -ENOMEM;
-
-	return error;
-}
-
-/**
- * nolock_unhold_lvb - release a LVB
- * @lock: the lock the LVB is associated with
- * @lvb: the lock value block
- *
- */
-
-static void nolock_unhold_lvb(void *lock, char *lvb)
-{
-	kfree(lvb);
-}
-
-static int nolock_mount(char *table_name, char *host_data,
-			lm_callback_t cb, void *cb_data,
-			unsigned int min_lvb_size, int flags,
-			struct lm_lockstruct *lockstruct,
-			struct kobject *fskobj);
-static void nolock_unmount(void *lockspace);
-
-/* List of registered low-level locking protocols.  A file system selects one
-   of them by name at mount time, e.g. lock_nolock, lock_dlm. */
-
-static const struct lm_lockops nolock_ops = {
-	.lm_proto_name = "lock_nolock",
-	.lm_mount = nolock_mount,
-	.lm_unmount = nolock_unmount,
-	.lm_get_lock = nolock_get_lock,
-	.lm_put_lock = nolock_put_lock,
-	.lm_hold_lvb = nolock_hold_lvb,
-	.lm_unhold_lvb = nolock_unhold_lvb,
-};
-
-static struct lmh_wrapper nolock_proto  = {
-	.lw_list = LIST_HEAD_INIT(nolock_proto.lw_list),
-	.lw_ops = &nolock_ops,
-};
-
-static LIST_HEAD(lmh_list);
-static DEFINE_MUTEX(lmh_lock);
-
-static int nolock_mount(char *table_name, char *host_data,
-			lm_callback_t cb, void *cb_data,
-			unsigned int min_lvb_size, int flags,
-			struct lm_lockstruct *lockstruct,
-			struct kobject *fskobj)
-{
-	char *c;
-	unsigned int jid;
-	struct nolock_lockspace *nl;
-
-	c = strstr(host_data, "jid=");
-	if (!c)
-		jid = 0;
-	else {
-		c += 4;
-		sscanf(c, "%u", &jid);
-	}
-
-	nl = kzalloc(sizeof(struct nolock_lockspace), GFP_KERNEL);
-	if (!nl)
-		return -ENOMEM;
-
-	nl->nl_lvb_size = min_lvb_size;
-
-	lockstruct->ls_jid = jid;
-	lockstruct->ls_first = 1;
-	lockstruct->ls_lvb_size = min_lvb_size;
-	lockstruct->ls_lockspace = nl;
-	lockstruct->ls_ops = &nolock_ops;
-	lockstruct->ls_flags = LM_LSFLAG_LOCAL;
-
-	return 0;
-}
-
-static void nolock_unmount(void *lockspace)
-{
-        struct nolock_lockspace *nl = lockspace;
-        kfree(nl);
-}
-
-/**
- * gfs2_register_lockproto - Register a low-level locking protocol
- * @proto: the protocol definition
- *
- * Returns: 0 on success, -EXXX on failure
- */
-
-int gfs2_register_lockproto(const struct lm_lockops *proto)
-{
-	struct lmh_wrapper *lw;
-
-	mutex_lock(&lmh_lock);
-
-	list_for_each_entry(lw, &lmh_list, lw_list) {
-		if (!strcmp(lw->lw_ops->lm_proto_name, proto->lm_proto_name)) {
-			mutex_unlock(&lmh_lock);
-			printk(KERN_INFO "GFS2: protocol %s already exists\n",
-			       proto->lm_proto_name);
-			return -EEXIST;
-		}
-	}
-
-	lw = kzalloc(sizeof(struct lmh_wrapper), GFP_KERNEL);
-	if (!lw) {
-		mutex_unlock(&lmh_lock);
-		return -ENOMEM;
-	}
-
-	lw->lw_ops = proto;
-	list_add(&lw->lw_list, &lmh_list);
-
-	mutex_unlock(&lmh_lock);
-
-	return 0;
-}
-
-/**
- * gfs2_unregister_lockproto - Unregister a low-level locking protocol
- * @proto: the protocol definition
- *
- */
-
-void gfs2_unregister_lockproto(const struct lm_lockops *proto)
-{
-	struct lmh_wrapper *lw;
-
-	mutex_lock(&lmh_lock);
-
-	list_for_each_entry(lw, &lmh_list, lw_list) {
-		if (!strcmp(lw->lw_ops->lm_proto_name, proto->lm_proto_name)) {
-			list_del(&lw->lw_list);
-			mutex_unlock(&lmh_lock);
-			kfree(lw);
-			return;
-		}
-	}
-
-	mutex_unlock(&lmh_lock);
-
-	printk(KERN_WARNING "GFS2: can't unregister lock protocol %s\n",
-	       proto->lm_proto_name);
-}
-
-/**
- * gfs2_mount_lockproto - Mount a lock protocol
- * @proto_name - the name of the protocol
- * @table_name - the name of the lock space
- * @host_data - data specific to this host
- * @cb - the callback to the code using the lock module
- * @sdp - The GFS2 superblock
- * @min_lvb_size - the mininum LVB size that the caller can deal with
- * @flags - LM_MFLAG_*
- * @lockstruct - a structure returned describing the mount
- *
- * Returns: 0 on success, -EXXX on failure
- */
-
-int gfs2_mount_lockproto(char *proto_name, char *table_name, char *host_data,
-			 lm_callback_t cb, void *cb_data,
-			 unsigned int min_lvb_size, int flags,
-			 struct lm_lockstruct *lockstruct,
-			 struct kobject *fskobj)
-{
-	struct lmh_wrapper *lw = NULL;
-	int try = 0;
-	int error, found;
-
-
-retry:
-	mutex_lock(&lmh_lock);
-
-	if (list_empty(&nolock_proto.lw_list))
-		list_add(&nolock_proto.lw_list, &lmh_list);
-
-	found = 0;
-	list_for_each_entry(lw, &lmh_list, lw_list) {
-		if (!strcmp(lw->lw_ops->lm_proto_name, proto_name)) {
-			found = 1;
-			break;
-		}
-	}
-
-	if (!found) {
-		if (!try && capable(CAP_SYS_MODULE)) {
-			try = 1;
-			mutex_unlock(&lmh_lock);
-			request_module(proto_name);
-			goto retry;
-		}
-		printk(KERN_INFO "GFS2: can't find protocol %s\n", proto_name);
-		error = -ENOENT;
-		goto out;
-	}
-
-	if (lw->lw_ops->lm_owner &&
-	    !try_module_get(lw->lw_ops->lm_owner)) {
-		try = 0;
-		mutex_unlock(&lmh_lock);
-		msleep(1000);
-		goto retry;
-	}
-
-	error = lw->lw_ops->lm_mount(table_name, host_data, cb, cb_data,
-				     min_lvb_size, flags, lockstruct, fskobj);
-	if (error)
-		module_put(lw->lw_ops->lm_owner);
-out:
-	mutex_unlock(&lmh_lock);
-	return error;
-}
-
-void gfs2_unmount_lockproto(struct lm_lockstruct *lockstruct)
-{
-	mutex_lock(&lmh_lock);
-	if (lockstruct->ls_ops->lm_unmount)
-		lockstruct->ls_ops->lm_unmount(lockstruct->ls_lockspace);
-	if (lockstruct->ls_ops->lm_owner)
-		module_put(lockstruct->ls_ops->lm_owner);
-	mutex_unlock(&lmh_lock);
-}
-
-/**
- * gfs2_withdraw_lockproto - abnormally unmount a lock module
- * @lockstruct: the lockstruct passed into mount
- *
- */
-
-void gfs2_withdraw_lockproto(struct lm_lockstruct *lockstruct)
-{
-	mutex_lock(&lmh_lock);
-	lockstruct->ls_ops->lm_withdraw(lockstruct->ls_lockspace);
-	if (lockstruct->ls_ops->lm_owner)
-		module_put(lockstruct->ls_ops->lm_owner);
-	mutex_unlock(&lmh_lock);
-}
-
-EXPORT_SYMBOL_GPL(gfs2_register_lockproto);
-EXPORT_SYMBOL_GPL(gfs2_unregister_lockproto);
-