[GFS2] The lock modules for GFS2

This patch contains the pluggable locking modules
for GFS2.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/gfs2/locking/dlm/Makefile

+obj-$(CONFIG_GFS2_FS) += lock_dlm.o
+lock_dlm-y := lock.o main.o mount.o sysfs.o thread.o
+

fs/gfs2/locking/dlm/main.c

+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 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 v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include <linux/init.h>
+
+#include "lock_dlm.h"
+
+extern int gdlm_drop_count;
+extern int gdlm_drop_period;
+
+extern struct lm_lockops gdlm_ops;
+
+int __init init_lock_dlm(void)
+{
+	int error;
+
+	error = lm_register_proto(&gdlm_ops);
+	if (error) {
+		printk("lock_dlm:  can't register protocol: %d\n", error);
+		return error;
+	}
+
+	error = gdlm_sysfs_init();
+	if (error) {
+		lm_unregister_proto(&gdlm_ops);
+		return error;
+	}
+
+	gdlm_drop_count = GDLM_DROP_COUNT;
+	gdlm_drop_period = GDLM_DROP_PERIOD;
+
+	printk("Lock_DLM (built %s %s) installed\n", __DATE__, __TIME__);
+	return 0;
+}
+
+void __exit exit_lock_dlm(void)
+{
+	lm_unregister_proto(&gdlm_ops);
+	gdlm_sysfs_exit();
+}
+
+module_init(init_lock_dlm);
+module_exit(exit_lock_dlm);
+
+MODULE_DESCRIPTION("GFS DLM Locking Module");
+MODULE_AUTHOR("Red Hat, Inc.");
+MODULE_LICENSE("GPL");
+

fs/gfs2/locking/dlm/mount.c

+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 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 v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "lock_dlm.h"
+
+int gdlm_drop_count;
+int gdlm_drop_period;
+struct lm_lockops gdlm_ops;
+
+
+static struct gdlm_ls *init_gdlm(lm_callback_t cb, lm_fsdata_t *fsdata,
+				 int flags, char *table_name)
+{
+	struct gdlm_ls *ls;
+	char buf[256], *p;
+
+	ls = kmalloc(sizeof(struct gdlm_ls), GFP_KERNEL);
+	if (!ls)
+		return NULL;
+
+	memset(ls, 0, sizeof(struct gdlm_ls));
+
+	ls->drop_locks_count = gdlm_drop_count;
+	ls->drop_locks_period = gdlm_drop_period;
+
+	ls->fscb = cb;
+	ls->fsdata = fsdata;
+	ls->fsflags = flags;
+
+	spin_lock_init(&ls->async_lock);
+
+	INIT_LIST_HEAD(&ls->complete);
+	INIT_LIST_HEAD(&ls->blocking);
+	INIT_LIST_HEAD(&ls->delayed);
+	INIT_LIST_HEAD(&ls->submit);
+	INIT_LIST_HEAD(&ls->all_locks);
+
+	init_waitqueue_head(&ls->thread_wait);
+	init_waitqueue_head(&ls->wait_control);
+	ls->thread1 = NULL;
+	ls->thread2 = NULL;
+	ls->drop_time = jiffies;
+	ls->jid = -1;
+
+	strncpy(buf, table_name, 256);
+	buf[255] = '\0';
+
+	p = strstr(buf, ":");
+	if (!p) {
+		printk("lock_dlm: invalid table_name \"%s\"\n", table_name);
+		kfree(ls);
+		return NULL;
+	}
+	*p = '\0';
+	p++;
+
+	strncpy(ls->clustername, buf, 128);
+	strncpy(ls->fsname, p, 128);
+
+	return ls;
+}
+
+static int gdlm_mount(char *table_name, char *host_data,
+			lm_callback_t cb, lm_fsdata_t *fsdata,
+			unsigned int min_lvb_size, int flags,
+			struct lm_lockstruct *lockstruct)
+{
+	struct gdlm_ls *ls;
+	int error = -ENOMEM;
+
+	if (min_lvb_size > GDLM_LVB_SIZE)
+		goto out;
+
+	ls = init_gdlm(cb, fsdata, flags, table_name);
+	if (!ls)
+		goto out;
+
+	error = gdlm_init_threads(ls);
+	if (error)
+		goto out_free;
+
+	error = dlm_new_lockspace(ls->fsname, strlen(ls->fsname),
+				  &ls->dlm_lockspace, 0, GDLM_LVB_SIZE);
+	if (error) {
+		printk("lock_dlm: dlm_new_lockspace error %d\n", error);
+		goto out_thread;
+	}
+
+	error = gdlm_kobject_setup(ls);
+	if (error)
+		goto out_dlm;
+	kobject_uevent(&ls->kobj, KOBJ_MOUNT, NULL);
+
+	/* Now we depend on userspace to notice the new mount,
+	   join the appropriate group, and do a write to our sysfs
+	   "mounted" or "terminate" file.  Before the start, userspace
+	   must set "jid" and "first". */
+
+	error = wait_event_interruptible(ls->wait_control,
+			test_bit(DFL_JOIN_DONE, &ls->flags));
+	if (error)
+		goto out_sysfs;
+
+	if (test_bit(DFL_TERMINATE, &ls->flags)) {
+		error = -ERESTARTSYS;
+		goto out_sysfs;
+	}
+
+	lockstruct->ls_jid = ls->jid;
+	lockstruct->ls_first = ls->first;
+	lockstruct->ls_lockspace = ls;
+	lockstruct->ls_ops = &gdlm_ops;
+	lockstruct->ls_flags = 0;
+	lockstruct->ls_lvb_size = GDLM_LVB_SIZE;
+	return 0;
+
+ out_sysfs:
+	gdlm_kobject_release(ls);
+ out_dlm:
+	dlm_release_lockspace(ls->dlm_lockspace, 2);
+ out_thread:
+	gdlm_release_threads(ls);
+ out_free:
+	kfree(ls);
+ out:
+	return error;
+}
+
+static void gdlm_unmount(lm_lockspace_t *lockspace)
+{
+	struct gdlm_ls *ls = (struct gdlm_ls *) lockspace;
+	int rv;
+
+	log_debug("unmount flags %lx", ls->flags);
+
+	if (test_bit(DFL_WITHDRAW, &ls->flags)) {
+		gdlm_kobject_release(ls);
+		goto out;
+	}
+
+	kobject_uevent(&ls->kobj, KOBJ_UMOUNT, NULL);
+
+	wait_event_interruptible(ls->wait_control,
+				 test_bit(DFL_LEAVE_DONE, &ls->flags));
+
+	gdlm_kobject_release(ls);
+	dlm_release_lockspace(ls->dlm_lockspace, 2);
+	gdlm_release_threads(ls);
+	rv = gdlm_release_all_locks(ls);
+	if (rv)
+		log_all("lm_dlm_unmount: %d stray locks freed", rv);
+ out:
+	kfree(ls);
+}
+
+static void gdlm_recovery_done(lm_lockspace_t *lockspace, unsigned int jid,
+                               unsigned int message)
+{
+	struct gdlm_ls *ls = (struct gdlm_ls *) lockspace;
+	ls->recover_done = jid;
+	kobject_uevent(&ls->kobj, KOBJ_CHANGE, NULL);
+}
+
+static void gdlm_others_may_mount(lm_lockspace_t *lockspace)
+{
+	struct gdlm_ls *ls = (struct gdlm_ls *) lockspace;
+	ls->first_done = 1;
+	kobject_uevent(&ls->kobj, KOBJ_CHANGE, NULL);
+}
+
+static void gdlm_withdraw(lm_lockspace_t *lockspace)
+{
+	struct gdlm_ls *ls = (struct gdlm_ls *) lockspace;
+
+	/* userspace suspends locking on all other members */
+
+	kobject_uevent(&ls->kobj, KOBJ_OFFLINE, NULL);
+
+	wait_event_interruptible(ls->wait_control,
+				 test_bit(DFL_WITHDRAW, &ls->flags));
+
+	dlm_release_lockspace(ls->dlm_lockspace, 2);
+	gdlm_release_threads(ls);
+	gdlm_release_all_locks(ls);
+
+	kobject_uevent(&ls->kobj, KOBJ_UMOUNT, NULL);
+
+	/* userspace leaves the mount group, we don't need to wait for
+	   that to complete */
+}
+
+int gdlm_plock_get(lm_lockspace_t *lockspace, struct lm_lockname *name,
+		   struct file *file, struct file_lock *fl)
+{
+	return -ENOSYS;
+}
+
+int gdlm_punlock(lm_lockspace_t *lockspace, struct lm_lockname *name,
+		   struct file *file, struct file_lock *fl)
+{
+	return -ENOSYS;
+}
+
+int gdlm_plock(lm_lockspace_t *lockspace, struct lm_lockname *name,
+	       struct file *file, int cmd, struct file_lock *fl)
+{
+	return -ENOSYS;
+}
+
+struct lm_lockops gdlm_ops = {
+	lm_proto_name:"lock_dlm",
+	lm_mount:gdlm_mount,
+	lm_others_may_mount:gdlm_others_may_mount,
+	lm_unmount:gdlm_unmount,
+	lm_withdraw:gdlm_withdraw,
+	lm_get_lock:gdlm_get_lock,
+	lm_put_lock:gdlm_put_lock,
+	lm_lock:gdlm_lock,
+	lm_unlock:gdlm_unlock,
+	lm_plock:gdlm_plock,
+	lm_punlock:gdlm_punlock,
+	lm_plock_get:gdlm_plock_get,
+	lm_cancel:gdlm_cancel,
+	lm_hold_lvb:gdlm_hold_lvb,
+	lm_unhold_lvb:gdlm_unhold_lvb,
+	lm_sync_lvb:gdlm_sync_lvb,
+	lm_recovery_done:gdlm_recovery_done,
+	lm_owner:THIS_MODULE,
+};
+

fs/gfs2/locking/dlm/sysfs.c

+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) 2005 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 v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include <linux/ctype.h>
+#include <linux/stat.h>
+
+#include "lock_dlm.h"
+
+static ssize_t gdlm_block_show(struct gdlm_ls *ls, char *buf)
+{
+	ssize_t ret;
+	int val = 0;
+
+	if (test_bit(DFL_BLOCK_LOCKS, &ls->flags))
+		val = 1;
+	ret = sprintf(buf, "%d\n", val);
+	return ret;
+}
+
+static ssize_t gdlm_block_store(struct gdlm_ls *ls, const char *buf, size_t len)
+{
+	ssize_t ret = len;
+	int val;
+
+	val = simple_strtol(buf, NULL, 0);
+
+	if (val == 1)
+		set_bit(DFL_BLOCK_LOCKS, &ls->flags);
+	else if (val == 0) {
+		clear_bit(DFL_BLOCK_LOCKS, &ls->flags);
+		gdlm_submit_delayed(ls);
+	} else
+		ret = -EINVAL;
+	return ret;
+}
+
+static ssize_t gdlm_mounted_show(struct gdlm_ls *ls, char *buf)
+{
+	ssize_t ret;
+	int val = -2;
+
+	if (test_bit(DFL_TERMINATE, &ls->flags))
+		val = -1;
+	else if (test_bit(DFL_LEAVE_DONE, &ls->flags))
+		val = 0;
+	else if (test_bit(DFL_JOIN_DONE, &ls->flags))
+		val = 1;
+	ret = sprintf(buf, "%d\n", val);
+	return ret;
+}
+
+static ssize_t gdlm_mounted_store(struct gdlm_ls *ls, const char *buf, size_t len)
+{
+	ssize_t ret = len;
+	int val;
+
+	val = simple_strtol(buf, NULL, 0);
+
+	if (val == 1)
+		set_bit(DFL_JOIN_DONE, &ls->flags);
+	else if (val == 0)
+		set_bit(DFL_LEAVE_DONE, &ls->flags);
+	else if (val == -1) {
+		set_bit(DFL_TERMINATE, &ls->flags);
+		set_bit(DFL_JOIN_DONE, &ls->flags);
+		set_bit(DFL_LEAVE_DONE, &ls->flags);
+	} else
+		ret = -EINVAL;
+	wake_up(&ls->wait_control);
+	return ret;
+}
+
+static ssize_t gdlm_withdraw_show(struct gdlm_ls *ls, char *buf)
+{
+	ssize_t ret;
+	int val = 0;
+
+	if (test_bit(DFL_WITHDRAW, &ls->flags))
+		val = 1;
+	ret = sprintf(buf, "%d\n", val);
+	return ret;
+}
+
+static ssize_t gdlm_withdraw_store(struct gdlm_ls *ls, const char *buf, size_t len)
+{
+	ssize_t ret = len;
+	int val;
+
+	val = simple_strtol(buf, NULL, 0);
+
+	if (val == 1)
+		set_bit(DFL_WITHDRAW, &ls->flags);
+	else
+		ret = -EINVAL;
+	wake_up(&ls->wait_control);
+	return ret;
+}
+
+static ssize_t gdlm_jid_show(struct gdlm_ls *ls, char *buf)
+{
+	return sprintf(buf, "%u\n", ls->jid);
+}
+
+static ssize_t gdlm_jid_store(struct gdlm_ls *ls, const char *buf, size_t len)
+{
+	ls->jid = simple_strtol(buf, NULL, 0);
+	return len;
+}
+
+static ssize_t gdlm_first_show(struct gdlm_ls *ls, char *buf)
+{
+	return sprintf(buf, "%u\n", ls->first);
+}
+
+static ssize_t gdlm_first_store(struct gdlm_ls *ls, const char *buf, size_t len)
+{
+	ls->first = simple_strtol(buf, NULL, 0);
+	return len;
+}
+
+static ssize_t gdlm_first_done_show(struct gdlm_ls *ls, char *buf)
+{
+	return sprintf(buf, "%d\n", ls->first_done);
+}
+
+static ssize_t gdlm_recover_show(struct gdlm_ls *ls, char *buf)
+{
+	return sprintf(buf, "%u\n", ls->recover_jid);
+}
+
+static ssize_t gdlm_recover_store(struct gdlm_ls *ls, const char *buf, size_t len)
+{
+	ls->recover_jid = simple_strtol(buf, NULL, 0);
+	ls->fscb(ls->fsdata, LM_CB_NEED_RECOVERY, &ls->recover_jid);
+	return len;
+}
+
+static ssize_t gdlm_recover_done_show(struct gdlm_ls *ls, char *buf)
+{
+	ssize_t ret;
+	ret = sprintf(buf, "%d\n", ls->recover_done);
+	return ret;
+}
+
+static ssize_t gdlm_cluster_show(struct gdlm_ls *ls, char *buf)
+{
+	ssize_t ret;
+	ret = sprintf(buf, "%s\n", ls->clustername);
+	return ret;
+}
+
+static ssize_t gdlm_options_show(struct gdlm_ls *ls, char *buf)
+{
+	ssize_t ret = 0;
+
+	if (ls->fsflags & LM_MFLAG_SPECTATOR)
+		ret += sprintf(buf, "spectator ");
+
+	return ret;
+}
+
+struct gdlm_attr {
+	struct attribute attr;
+	ssize_t (*show)(struct gdlm_ls *, char *);
+	ssize_t (*store)(struct gdlm_ls *, const char *, size_t);
+};
+
+static struct gdlm_attr gdlm_attr_block = {
+	.attr  = {.name = "block", .mode = S_IRUGO | S_IWUSR},
+	.show  = gdlm_block_show,
+	.store = gdlm_block_store
+};
+
+static struct gdlm_attr gdlm_attr_mounted = {
+	.attr  = {.name = "mounted", .mode = S_IRUGO | S_IWUSR},
+	.show  = gdlm_mounted_show,
+	.store = gdlm_mounted_store
+};
+
+static struct gdlm_attr gdlm_attr_withdraw = {
+	.attr  = {.name = "withdraw", .mode = S_IRUGO | S_IWUSR},
+	.show  = gdlm_withdraw_show,
+	.store = gdlm_withdraw_store
+};
+
+static struct gdlm_attr gdlm_attr_jid = {
+	.attr  = {.name = "jid", .mode = S_IRUGO | S_IWUSR},
+	.show  = gdlm_jid_show,
+	.store = gdlm_jid_store
+};
+
+static struct gdlm_attr gdlm_attr_first = {
+	.attr  = {.name = "first", .mode = S_IRUGO | S_IWUSR},
+	.show  = gdlm_first_show,
+	.store = gdlm_first_store
+};
+
+static struct gdlm_attr gdlm_attr_first_done = {
+	.attr  = {.name = "first_done", .mode = S_IRUGO},
+	.show  = gdlm_first_done_show,
+};
+
+static struct gdlm_attr gdlm_attr_recover = {
+	.attr  = {.name = "recover", .mode = S_IRUGO | S_IWUSR},
+	.show  = gdlm_recover_show,
+	.store = gdlm_recover_store
+};
+
+static struct gdlm_attr gdlm_attr_recover_done = {
+	.attr  = {.name = "recover_done", .mode = S_IRUGO | S_IWUSR},
+	.show  = gdlm_recover_done_show,
+};
+
+static struct gdlm_attr gdlm_attr_cluster = {
+	.attr  = {.name = "cluster", .mode = S_IRUGO | S_IWUSR},
+	.show  = gdlm_cluster_show,
+};
+
+static struct gdlm_attr gdlm_attr_options = {
+	.attr  = {.name = "options", .mode = S_IRUGO | S_IWUSR},
+	.show  = gdlm_options_show,
+};
+
+static struct attribute *gdlm_attrs[] = {
+	&gdlm_attr_block.attr,
+	&gdlm_attr_mounted.attr,
+	&gdlm_attr_withdraw.attr,
+	&gdlm_attr_jid.attr,
+	&gdlm_attr_first.attr,
+	&gdlm_attr_first_done.attr,
+	&gdlm_attr_recover.attr,
+	&gdlm_attr_recover_done.attr,
+	&gdlm_attr_cluster.attr,
+	&gdlm_attr_options.attr,
+	NULL,
+};
+
+static ssize_t gdlm_attr_show(struct kobject *kobj, struct attribute *attr,
+			      char *buf)
+{
+	struct gdlm_ls *ls = container_of(kobj, struct gdlm_ls, kobj);
+	struct gdlm_attr *a = container_of(attr, struct gdlm_attr, attr);
+	return a->show ? a->show(ls, buf) : 0;
+}
+
+static ssize_t gdlm_attr_store(struct kobject *kobj, struct attribute *attr,
+			       const char *buf, size_t len)
+{
+	struct gdlm_ls *ls = container_of(kobj, struct gdlm_ls, kobj);
+	struct gdlm_attr *a = container_of(attr, struct gdlm_attr, attr);
+	return a->store ? a->store(ls, buf, len) : len;
+}
+
+static struct sysfs_ops gdlm_attr_ops = {
+	.show  = gdlm_attr_show,
+	.store = gdlm_attr_store,
+};
+
+static struct kobj_type gdlm_ktype = {
+	.default_attrs = gdlm_attrs,
+	.sysfs_ops     = &gdlm_attr_ops,
+};
+
+static struct kset gdlm_kset = {
+	.subsys = &kernel_subsys,
+	.kobj   = {.name = "lock_dlm",},
+	.ktype  = &gdlm_ktype,
+};
+
+int gdlm_kobject_setup(struct gdlm_ls *ls)
+{
+	int error;
+
+	error = kobject_set_name(&ls->kobj, "%s", ls->fsname);
+	if (error)
+		return error;
+
+	ls->kobj.kset = &gdlm_kset;
+	ls->kobj.ktype = &gdlm_ktype;
+
+	error = kobject_register(&ls->kobj);
+
+	return 0;
+}
+
+void gdlm_kobject_release(struct gdlm_ls *ls)
+{
+	kobject_unregister(&ls->kobj);
+}
+
+int gdlm_sysfs_init(void)
+{
+	int error;
+
+	error = kset_register(&gdlm_kset);
+	if (error)
+		printk("lock_dlm: cannot register kset %d\n", error);
+
+	return error;
+}
+
+void gdlm_sysfs_exit(void)
+{
+	kset_unregister(&gdlm_kset);
+}
+

fs/gfs2/locking/dlm/thread.c

+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 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 v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include "lock_dlm.h"
+
+/* A lock placed on this queue is re-submitted to DLM as soon as the lock_dlm
+   thread gets to it. */
+
+static void queue_submit(struct gdlm_lock *lp)
+{
+	struct gdlm_ls *ls = lp->ls;
+
+	spin_lock(&ls->async_lock);
+	list_add_tail(&lp->delay_list, &ls->submit);
+	spin_unlock(&ls->async_lock);
+	wake_up(&ls->thread_wait);
+}
+
+static void process_submit(struct gdlm_lock *lp)
+{
+	gdlm_do_lock(lp, NULL);
+}
+
+static void process_blocking(struct gdlm_lock *lp, int bast_mode)
+{
+	struct gdlm_ls *ls = lp->ls;
+	unsigned int cb;
+
+	switch (gdlm_make_lmstate(bast_mode)) {
+	case LM_ST_EXCLUSIVE:
+		cb = LM_CB_NEED_E;
+		break;
+	case LM_ST_DEFERRED:
+		cb = LM_CB_NEED_D;
+		break;
+	case LM_ST_SHARED:
+		cb = LM_CB_NEED_S;
+		break;
+	default:
+		GDLM_ASSERT(0, printk("unknown bast mode %u\n",lp->bast_mode););
+	}
+
+	ls->fscb(ls->fsdata, cb, &lp->lockname);
+}
+
+static void process_complete(struct gdlm_lock *lp)
+{
+	struct gdlm_ls *ls = lp->ls;
+	struct lm_async_cb acb;
+	int16_t prev_mode = lp->cur;
+
+	memset(&acb, 0, sizeof(acb));
+
+	if (lp->lksb.sb_status == -DLM_ECANCEL) {
+		log_all("complete dlm cancel %x,%"PRIx64" flags %lx",
+			lp->lockname.ln_type, lp->lockname.ln_number,
+			lp->flags);
+
+		lp->req = lp->cur;
+		acb.lc_ret |= LM_OUT_CANCELED;
+		if (lp->cur == DLM_LOCK_IV)
+			lp->lksb.sb_lkid = 0;
+		goto out;
+	}
+
+	if (test_and_clear_bit(LFL_DLM_UNLOCK, &lp->flags)) {
+		if (lp->lksb.sb_status != -DLM_EUNLOCK) {
+			log_all("unlock sb_status %d %x,%"PRIx64" flags %lx",
+				lp->lksb.sb_status, lp->lockname.ln_type,
+				lp->lockname.ln_number, lp->flags);
+			return;
+		}
+
+		lp->cur = DLM_LOCK_IV;
+		lp->req = DLM_LOCK_IV;
+		lp->lksb.sb_lkid = 0;
+
+		if (test_and_clear_bit(LFL_UNLOCK_DELETE, &lp->flags)) {
+			gdlm_delete_lp(lp);
+			return;
+		}
+		goto out;
+	}
+
+	if (lp->lksb.sb_flags & DLM_SBF_VALNOTVALID)
+		memset(lp->lksb.sb_lvbptr, 0, GDLM_LVB_SIZE);
+
+	if (lp->lksb.sb_flags & DLM_SBF_ALTMODE) {
+		if (lp->req == DLM_LOCK_PR)
+			lp->req = DLM_LOCK_CW;
+		else if (lp->req == DLM_LOCK_CW)
+			lp->req = DLM_LOCK_PR;
+	}
+
+	/*
+	 * A canceled lock request.  The lock was just taken off the delayed
+	 * list and was never even submitted to dlm.
+	 */
+
+	if (test_and_clear_bit(LFL_CANCEL, &lp->flags)) {
+		log_all("complete internal cancel %x,%"PRIx64"",
+			lp->lockname.ln_type, lp->lockname.ln_number);
+		lp->req = lp->cur;
+		acb.lc_ret |= LM_OUT_CANCELED;
+		goto out;
+	}
+
+	/*
+	 * An error occured.
+	 */
+
+	if (lp->lksb.sb_status) {
+		/* a "normal" error */
+		if ((lp->lksb.sb_status == -EAGAIN) &&
+		    (lp->lkf & DLM_LKF_NOQUEUE)) {
+			lp->req = lp->cur;
+			if (lp->cur == DLM_LOCK_IV)
+				lp->lksb.sb_lkid = 0;
+			goto out;
+		}
+
+		/* this could only happen with cancels I think */
+		log_all("ast sb_status %d %x,%"PRIx64" flags %lx",
+			lp->lksb.sb_status, lp->lockname.ln_type,
+			lp->lockname.ln_number, lp->flags);
+		return;
+	}
+
+	/*
+	 * This is an AST for an EX->EX conversion for sync_lvb from GFS.
+	 */
+
+	if (test_and_clear_bit(LFL_SYNC_LVB, &lp->flags)) {
+		complete(&lp->ast_wait);
+		return;
+	}
+
+	/*
+	 * A lock has been demoted to NL because it initially completed during
+	 * BLOCK_LOCKS.  Now it must be requested in the originally requested
+	 * mode.
+	 */
+
+	if (test_and_clear_bit(LFL_REREQUEST, &lp->flags)) {
+		GDLM_ASSERT(lp->req == DLM_LOCK_NL,);
+		GDLM_ASSERT(lp->prev_req > DLM_LOCK_NL,);
+
+		lp->cur = DLM_LOCK_NL;
+		lp->req = lp->prev_req;
+		lp->prev_req = DLM_LOCK_IV;
+		lp->lkf &= ~DLM_LKF_CONVDEADLK;
+
+		set_bit(LFL_NOCACHE, &lp->flags);
+
+		if (test_bit(DFL_BLOCK_LOCKS, &ls->flags) &&
+		    !test_bit(LFL_NOBLOCK, &lp->flags))
+			gdlm_queue_delayed(lp);
+		else
+			queue_submit(lp);
+		return;
+	}
+
+	/*
+	 * A request is granted during dlm recovery.  It may be granted
+	 * because the locks of a failed node were cleared.  In that case,
+	 * there may be inconsistent data beneath this lock and we must wait
+	 * for recovery to complete to use it.  When gfs recovery is done this
+	 * granted lock will be converted to NL and then reacquired in this
+	 * granted state.
+	 */
+
+	if (test_bit(DFL_BLOCK_LOCKS, &ls->flags) &&
+	    !test_bit(LFL_NOBLOCK, &lp->flags) &&
+	    lp->req != DLM_LOCK_NL) {
+
+		lp->cur = lp->req;
+		lp->prev_req = lp->req;
+		lp->req = DLM_LOCK_NL;
+		lp->lkf |= DLM_LKF_CONVERT;
+		lp->lkf &= ~DLM_LKF_CONVDEADLK;
+
+		log_debug("rereq %x,%"PRIx64" id %x %d,%d",
+			  lp->lockname.ln_type, lp->lockname.ln_number,
+			  lp->lksb.sb_lkid, lp->cur, lp->req);
+
+		set_bit(LFL_REREQUEST, &lp->flags);
+		queue_submit(lp);
+		return;
+	}
+
+	/*
+	 * DLM demoted the lock to NL before it was granted so GFS must be
+	 * told it cannot cache data for this lock.
+	 */
+
+	if (lp->lksb.sb_flags & DLM_SBF_DEMOTED)
+		set_bit(LFL_NOCACHE, &lp->flags);
+
+ out:
+	/*
+	 * This is an internal lock_dlm lock
+	 */
+
+	if (test_bit(LFL_INLOCK, &lp->flags)) {
+		clear_bit(LFL_NOBLOCK, &lp->flags);
+		lp->cur = lp->req;
+		complete(&lp->ast_wait);
+		return;
+	}
+
+	/*
+	 * Normal completion of a lock request.  Tell GFS it now has the lock.
+	 */
+
+	clear_bit(LFL_NOBLOCK, &lp->flags);
+	lp->cur = lp->req;
+
+	acb.lc_name = lp->lockname;
+	acb.lc_ret |= gdlm_make_lmstate(lp->cur);
+
+	if (!test_and_clear_bit(LFL_NOCACHE, &lp->flags) &&
+	    (lp->cur > DLM_LOCK_NL) && (prev_mode > DLM_LOCK_NL))
+		acb.lc_ret |= LM_OUT_CACHEABLE;
+
+	ls->fscb(ls->fsdata, LM_CB_ASYNC, &acb);
+}
+
+static inline int no_work(struct gdlm_ls *ls, int blocking)
+{
+	int ret;
+
+	spin_lock(&ls->async_lock);
+	ret = list_empty(&ls->complete) && list_empty(&ls->submit);
+	if (ret && blocking)
+		ret = list_empty(&ls->blocking);
+	spin_unlock(&ls->async_lock);
+
+	return ret;
+}
+
+static inline int check_drop(struct gdlm_ls *ls)
+{
+	if (!ls->drop_locks_count)
+		return 0;
+
+	if (time_after(jiffies, ls->drop_time + ls->drop_locks_period * HZ)) {
+		ls->drop_time = jiffies;
+		if (ls->all_locks_count >= ls->drop_locks_count)
+			return 1;
+	}
+	return 0;
+}
+
+static int gdlm_thread(void *data)
+{
+	struct gdlm_ls *ls = (struct gdlm_ls *) data;
+	struct gdlm_lock *lp = NULL;
+	int blist = 0;
+	uint8_t complete, blocking, submit, drop;
+	DECLARE_WAITQUEUE(wait, current);
+
+	/* Only thread1 is allowed to do blocking callbacks since gfs
+	   may wait for a completion callback within a blocking cb. */
+
+	if (current == ls->thread1)
+		blist = 1;
+
+	while (!kthread_should_stop()) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		add_wait_queue(&ls->thread_wait, &wait);
+		if (no_work(ls, blist))
+			schedule();
+		remove_wait_queue(&ls->thread_wait, &wait);
+		set_current_state(TASK_RUNNING);
+
+		complete = blocking = submit = drop = 0;
+
+		spin_lock(&ls->async_lock);
+
+		if (blist && !list_empty(&ls->blocking)) {
+			lp = list_entry(ls->blocking.next, struct gdlm_lock,
+					blist);
+			list_del_init(&lp->blist);
+			blocking = lp->bast_mode;
+			lp->bast_mode = 0;
+		} else if (!list_empty(&ls->complete)) {
+			lp = list_entry(ls->complete.next, struct gdlm_lock,
+					clist);
+			list_del_init(&lp->clist);
+			complete = 1;
+		} else if (!list_empty(&ls->submit)) {
+			lp = list_entry(ls->submit.next, struct gdlm_lock,
+					delay_list);
+			list_del_init(&lp->delay_list);
+			submit = 1;
+		}
+
+		drop = check_drop(ls);
+		spin_unlock(&ls->async_lock);
+
+		if (complete)
+			process_complete(lp);
+
+		else if (blocking)
+			process_blocking(lp, blocking);
+
+		else if (submit)
+			process_submit(lp);
+
+		if (drop)
+			ls->fscb(ls->fsdata, LM_CB_DROPLOCKS, NULL);
+
+		schedule();
+	}
+
+	return 0;
+}
+
+int gdlm_init_threads(struct gdlm_ls *ls)
+{
+	struct task_struct *p;
+	int error;
+
+	p = kthread_run(gdlm_thread, ls, "lock_dlm1");
+	error = IS_ERR(p);
+	if (error) {
+		log_all("can't start lock_dlm1 thread %d", error);
+		return error;
+	}
+	ls->thread1 = p;
+
+	p = kthread_run(gdlm_thread, ls, "lock_dlm2");
+	error = IS_ERR(p);
+	if (error) {
+		log_all("can't start lock_dlm2 thread %d", error);
+		kthread_stop(ls->thread1);
+		return error;
+	}
+	ls->thread2 = p;
+
+	return 0;
+}
+
+void gdlm_release_threads(struct gdlm_ls *ls)
+{
+	kthread_stop(ls->thread1);
+	kthread_stop(ls->thread2);
+}
+

fs/gfs2/locking/nolock/Makefile

+obj-$(CONFIG_GFS2_FS) += lock_nolock.o
+lock_nolock-y := main.o
+

fs/gfs2/locking/nolock/lock_nolock.mod.c

+#include <linux/module.h>
+#include <linux/vermagic.h>
+#include <linux/compiler.h>
+
+MODULE_INFO(vermagic, VERMAGIC_STRING);
+
+#undef unix
+struct module __this_module
+__attribute__((section(".gnu.linkonce.this_module"))) = {
+ .name = __stringify(KBUILD_MODNAME),
+ .init = init_module,
+#ifdef CONFIG_MODULE_UNLOAD
+ .exit = cleanup_module,
+#endif
+};
+
+static const struct modversion_info ____versions[]
+__attribute_used__
+__attribute__((section("__versions"))) = {
+	{ 0x316962fc, "struct_module" },
+	{ 0x5a34a45c, "__kmalloc" },
+	{ 0x724beef2, "malloc_sizes" },
+	{ 0x3fa03a97, "memset" },
+	{ 0xc16fe12d, "__memcpy" },
+	{ 0xdd132261, "printk" },
+	{ 0x859204af, "sscanf" },
+	{ 0x3656bf5a, "lock_kernel" },
+	{ 0x1e6d26a8, "strstr" },
+	{ 0x41ede9df, "lm_register_proto" },
+	{ 0xb1f975aa, "unlock_kernel" },
+	{ 0x87b0b01f, "posix_lock_file_wait" },
+	{ 0x75f29cfd, "kmem_cache_alloc" },
+	{ 0x69384280, "lm_unregister_proto" },
+	{ 0x37a0cba, "kfree" },
+	{ 0x5d16bfe6, "posix_test_lock" },
+};
+
+static const char __module_depends[]
+__attribute_used__
+__attribute__((section(".modinfo"))) =
+"depends=gfs2";
+
+
+MODULE_INFO(srcversion, "123E446F965A386A0C017C4");

fs/gfs2/locking/nolock/main.c

+/******************************************************************************
+*******************************************************************************
+**
+**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
+**  Copyright (C) 2004-2005 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 v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/smp_lock.h>
+
+#include "../../lm_interface.h"
+
+struct nolock_lockspace {
+	unsigned int nl_lvb_size;
+};
+
+struct lm_lockops nolock_ops;
+
+/**
+ * nolock_mount - mount a nolock lockspace
+ * @table_name: the name of the space to mount
+ * @host_data: host specific data
+ * @cb: the callback
+ * @fsdata:
+ * @min_lvb_size:
+ * @flags:
+ * @lockstruct: the structure of crap to fill in
+ *
+ * Returns: 0 on success, -EXXX on failure
+ */
+
+static int nolock_mount(char *table_name, char *host_data,
+			lm_callback_t cb, lm_fsdata_t *fsdata,
+			unsigned int min_lvb_size, int flags,
+			struct lm_lockstruct *lockstruct)
+{
+	char *c;
+	unsigned int jid;
+	struct nolock_lockspace *nl;
+
+	/* If there is a "jid=" in the hostdata, return that jid.
+	   Otherwise, return zero. */
+
+	c = strstr(host_data, "jid=");
+	if (!c)
+		jid = 0;
+	else {
+		c += 4;
+		sscanf(c, "%u", &jid);
+	}
+
+	nl = kmalloc(sizeof(struct nolock_lockspace), GFP_KERNEL);
+	if (!nl)
+		return -ENOMEM;
+
+	memset(nl, 0, sizeof(struct nolock_lockspace));
+	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 = (lm_lockspace_t *)nl;
+	lockstruct->ls_ops = &nolock_ops;
+	lockstruct->ls_flags = LM_LSFLAG_LOCAL;
+
+	return 0;
+}
+
+/**
+ * nolock_others_may_mount - unmount a lock space
+ * @lockspace: the lockspace to unmount
+ *
+ */
+
+static void nolock_others_may_mount(lm_lockspace_t *lockspace)
+{
+}
+
+/**
+ * nolock_unmount - unmount a lock space
+ * @lockspace: the lockspace to unmount
+ *
+ */
+
+static void nolock_unmount(lm_lockspace_t *lockspace)
+{
+	struct nolock_lockspace *nl = (struct nolock_lockspace *)lockspace;
+	kfree(nl);
+}
+
+/**
+ * nolock_withdraw - withdraw from a lock space
+ * @lockspace: the lockspace
+ *
+ */
+
+static void nolock_withdraw(lm_lockspace_t *lockspace)
+{
+}
+
+/**
+ * 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(lm_lockspace_t *lockspace, struct lm_lockname *name,
+			   lm_lock_t **lockp)
+{
+	*lockp = (lm_lock_t *)lockspace;
+	return 0;
+}
+
+/**
+ * nolock_put_lock - get rid of a lock structure
+ * @lock: the lock to throw away
+ *
+ */
+
+static void nolock_put_lock(lm_lock_t *lock)
+{
+}
+
+/**
+ * nolock_lock - acquire a lock
+ * @lock: the lock to manipulate
+ * @cur_state: the current state
+ * @req_state: the requested state
+ * @flags: modifier flags
+ *
+ * Returns: A bitmap of LM_OUT_*
+ */
+
+static unsigned int nolock_lock(lm_lock_t *lock, unsigned int cur_state,
+				unsigned int req_state, unsigned int flags)
+{
+	return req_state | LM_OUT_CACHEABLE;
+}
+
+/**
+ * nolock_unlock - unlock a lock
+ * @lock: the lock to manipulate
+ * @cur_state: the current state
+ *
+ * Returns: 0
+ */
+
+static unsigned int nolock_unlock(lm_lock_t *lock, unsigned int cur_state)
+{
+	return 0;
+}
+
+/**
+ * nolock_cancel - cancel a request on a lock
+ * @lock: the lock to cancel request for
+ *
+ */
+
+static void nolock_cancel(lm_lock_t *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(lm_lock_t *lock, char **lvbp)
+{
+	struct nolock_lockspace *nl = (struct nolock_lockspace *)lock;
+	int error = 0;
+
+	*lvbp = kmalloc(nl->nl_lvb_size, GFP_KERNEL);
+	if (*lvbp)
+		memset(*lvbp, 0, nl->nl_lvb_size);
+	else
+		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(lm_lock_t *lock, char *lvb)
+{
+	kfree(lvb);
+}
+
+/**
+ * nolock_sync_lvb - sync out the value of a lvb
+ * @lock: the lock the LVB is associated with
+ * @lvb: the lock value block
+ *
+ */
+
+static void nolock_sync_lvb(lm_lock_t *lock, char *lvb)
+{
+}
+
+/**
+ * nolock_plock_get -
+ * @lockspace: the lockspace
+ * @name:
+ * @file:
+ * @fl:
+ *
+ * Returns: errno
+ */
+
+static int nolock_plock_get(lm_lockspace_t *lockspace, struct lm_lockname *name,
+			    struct file *file, struct file_lock *fl)
+{
+	struct file_lock *tmp;
+
+	lock_kernel();
+	tmp = posix_test_lock(file, fl);
+	fl->fl_type = F_UNLCK;
+	if (tmp)
+		memcpy(fl, tmp, sizeof(struct file_lock));
+	unlock_kernel();
+
+	return 0;
+}
+
+/**
+ * nolock_plock -
+ * @lockspace: the lockspace
+ * @name:
+ * @file:
+ * @cmd:
+ * @fl:
+ *
+ * Returns: errno
+ */
+
+static int nolock_plock(lm_lockspace_t *lockspace, struct lm_lockname *name,
+			struct file *file, int cmd, struct file_lock *fl)
+{
+	int error;
+	lock_kernel();
+	error = posix_lock_file_wait(file, fl);
+	unlock_kernel();
+	return error;
+}
+
+/**
+ * nolock_punlock -
+ * @lockspace: the lockspace
+ * @name:
+ * @file:
+ * @fl:
+ *
+ * Returns: errno
+ */
+
+static int nolock_punlock(lm_lockspace_t *lockspace, struct lm_lockname *name,
+			  struct file *file, struct file_lock *fl)
+{
+	int error;
+	lock_kernel();
+	error = posix_lock_file_wait(file, fl);
+	unlock_kernel();
+	return error;
+}
+
+/**
+ * nolock_recovery_done - reset the expired locks for a given jid
+ * @lockspace: the lockspace
+ * @jid: the jid
+ *
+ */
+
+static void nolock_recovery_done(lm_lockspace_t *lockspace, unsigned int jid,
+				 unsigned int message)
+{
+}
+
+struct lm_lockops nolock_ops = {
+	.lm_proto_name = "lock_nolock",
+	.lm_mount = nolock_mount,
+	.lm_others_may_mount = nolock_others_may_mount,
+	.lm_unmount = nolock_unmount,
+	.lm_withdraw = nolock_withdraw,
+	.lm_get_lock = nolock_get_lock,
+	.lm_put_lock = nolock_put_lock,
+	.lm_lock = nolock_lock,
+	.lm_unlock = nolock_unlock,
+	.lm_cancel = nolock_cancel,
+	.lm_hold_lvb = nolock_hold_lvb,
+	.lm_unhold_lvb = nolock_unhold_lvb,
+	.lm_sync_lvb = nolock_sync_lvb,
+	.lm_plock_get = nolock_plock_get,
+	.lm_plock = nolock_plock,
+	.lm_punlock = nolock_punlock,
+	.lm_recovery_done = nolock_recovery_done,
+	.lm_owner = THIS_MODULE,
+};
+
+/**
+ * init_nolock - Initialize the nolock module
+ *
+ * Returns: 0 on success, -EXXX on failure
+ */
+
+int __init init_nolock(void)
+{
+	int error;
+
+	error = lm_register_proto(&nolock_ops);
+	if (error) {
+		printk("lock_nolock: can't register protocol: %d\n", error);
+		return error;
+	}
+
+	printk("Lock_Nolock (built %s %s) installed\n", __DATE__, __TIME__);
+	return 0;
+}
+
+/**
+ * exit_nolock - cleanup the nolock module
+ *
+ */
+
+void __exit exit_nolock(void)
+{
+	lm_unregister_proto(&nolock_ops);
+}
+
+module_init(init_nolock);
+module_exit(exit_nolock);
+
+MODULE_DESCRIPTION("GFS Nolock Locking Module");
+MODULE_AUTHOR("Red Hat, Inc.");
+MODULE_LICENSE("GPL");
+