[DLM] The core of the DLM for GFS2/CLVM

This is the core of the distributed lock manager which is required
to use GFS2 as a cluster filesystem. It is also used by CLVM and
can be used as a standalone lock manager independantly of either
of these two projects.

It implements VAX-style locking modes.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steve Whitehouse <swhiteho@redhat.com>

1 files changed, 314 insertions, 0 deletions

diff --git a/fs/dlm/member.c b/fs/dlm/member.c
new file mode 100644
index 00000000000..439249b62a5
--- /dev/null
+++ b/fs/dlm/member.c
@@ -0,0 +1,314 @@
+/******************************************************************************
+*******************************************************************************
+**
+**  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 "dlm_internal.h"
+#include "lockspace.h"
+#include "member.h"
+#include "recoverd.h"
+#include "recover.h"
+#include "lowcomms.h"
+#include "rcom.h"
+#include "config.h"
+
+/*
+ * Following called by dlm_recoverd thread
+ */
+
+static void add_ordered_member(struct dlm_ls *ls, struct dlm_member *new)
+{
+	struct dlm_member *memb = NULL;
+	struct list_head *tmp;
+	struct list_head *newlist = &new->list;
+	struct list_head *head = &ls->ls_nodes;
+
+	list_for_each(tmp, head) {
+		memb = list_entry(tmp, struct dlm_member, list);
+		if (new->nodeid < memb->nodeid)
+			break;
+	}
+
+	if (!memb)
+		list_add_tail(newlist, head);
+	else {
+		/* FIXME: can use list macro here */
+		newlist->prev = tmp->prev;
+		newlist->next = tmp;
+		tmp->prev->next = newlist;
+		tmp->prev = newlist;
+	}
+}
+
+static int dlm_add_member(struct dlm_ls *ls, int nodeid)
+{
+	struct dlm_member *memb;
+	int w;
+
+	memb = kmalloc(sizeof(struct dlm_member), GFP_KERNEL);
+	if (!memb)
+		return -ENOMEM;
+
+	w = dlm_node_weight(ls->ls_name, nodeid);
+	if (w < 0)
+		return w;
+
+	memb->nodeid = nodeid;
+	memb->weight = w;
+	add_ordered_member(ls, memb);
+	ls->ls_num_nodes++;
+	return 0;
+}
+
+static void dlm_remove_member(struct dlm_ls *ls, struct dlm_member *memb)
+{
+	list_move(&memb->list, &ls->ls_nodes_gone);
+	ls->ls_num_nodes--;
+}
+
+static int dlm_is_member(struct dlm_ls *ls, int nodeid)
+{
+	struct dlm_member *memb;
+
+	list_for_each_entry(memb, &ls->ls_nodes, list) {
+		if (memb->nodeid == nodeid)
+			return TRUE;
+	}
+	return FALSE;
+}
+
+int dlm_is_removed(struct dlm_ls *ls, int nodeid)
+{
+	struct dlm_member *memb;
+
+	list_for_each_entry(memb, &ls->ls_nodes_gone, list) {
+		if (memb->nodeid == nodeid)
+			return TRUE;
+	}
+	return FALSE;
+}
+
+static void clear_memb_list(struct list_head *head)
+{
+	struct dlm_member *memb;
+
+	while (!list_empty(head)) {
+		memb = list_entry(head->next, struct dlm_member, list);
+		list_del(&memb->list);
+		kfree(memb);
+	}
+}
+
+void dlm_clear_members(struct dlm_ls *ls)
+{
+	clear_memb_list(&ls->ls_nodes);
+	ls->ls_num_nodes = 0;
+}
+
+void dlm_clear_members_gone(struct dlm_ls *ls)
+{
+	clear_memb_list(&ls->ls_nodes_gone);
+}
+
+static void make_member_array(struct dlm_ls *ls)
+{
+	struct dlm_member *memb;
+	int i, w, x = 0, total = 0, all_zero = 0, *array;
+
+	kfree(ls->ls_node_array);
+	ls->ls_node_array = NULL;
+
+	list_for_each_entry(memb, &ls->ls_nodes, list) {
+		if (memb->weight)
+			total += memb->weight;
+	}
+
+	/* all nodes revert to weight of 1 if all have weight 0 */
+
+	if (!total) {
+		total = ls->ls_num_nodes;
+		all_zero = 1;
+	}
+
+	ls->ls_total_weight = total;
+
+	array = kmalloc(sizeof(int) * total, GFP_KERNEL);
+	if (!array)
+		return;
+
+	list_for_each_entry(memb, &ls->ls_nodes, list) {
+		if (!all_zero && !memb->weight)
+			continue;
+
+		if (all_zero)
+			w = 1;
+		else
+			w = memb->weight;
+
+		DLM_ASSERT(x < total, printk("total %d x %d\n", total, x););
+
+		for (i = 0; i < w; i++)
+			array[x++] = memb->nodeid;
+	}
+
+	ls->ls_node_array = array;
+}
+
+/* send a status request to all members just to establish comms connections */
+
+static void ping_members(struct dlm_ls *ls)
+{
+	struct dlm_member *memb;
+	list_for_each_entry(memb, &ls->ls_nodes, list)
+		dlm_rcom_status(ls, memb->nodeid);
+}
+
+int dlm_recover_members(struct dlm_ls *ls, struct dlm_recover *rv, int *neg_out)
+{
+	struct dlm_member *memb, *safe;
+	int i, error, found, pos = 0, neg = 0, low = -1;
+
+	/* move departed members from ls_nodes to ls_nodes_gone */
+
+	list_for_each_entry_safe(memb, safe, &ls->ls_nodes, list) {
+		found = FALSE;
+		for (i = 0; i < rv->node_count; i++) {
+			if (memb->nodeid == rv->nodeids[i]) {
+				found = TRUE;
+				break;
+			}
+		}
+
+		if (!found) {
+			neg++;
+			dlm_remove_member(ls, memb);
+			log_debug(ls, "remove member %d", memb->nodeid);
+		}
+	}
+
+	/* add new members to ls_nodes */
+
+	for (i = 0; i < rv->node_count; i++) {
+		if (dlm_is_member(ls, rv->nodeids[i]))
+			continue;
+		dlm_add_member(ls, rv->nodeids[i]);
+		pos++;
+		log_debug(ls, "add member %d", rv->nodeids[i]);
+	}
+
+	list_for_each_entry(memb, &ls->ls_nodes, list) {
+		if (low == -1 || memb->nodeid < low)
+			low = memb->nodeid;
+	}
+	ls->ls_low_nodeid = low;
+
+	make_member_array(ls);
+	dlm_set_recover_status(ls, DLM_RS_NODES);
+	*neg_out = neg;
+
+	ping_members(ls);
+
+	error = dlm_recover_members_wait(ls);
+	log_debug(ls, "total members %d", ls->ls_num_nodes);
+	return error;
+}
+
+/*
+ * Following called from lockspace.c
+ */
+
+int dlm_ls_stop(struct dlm_ls *ls)
+{
+	int new;
+
+	/*
+	 * A stop cancels any recovery that's in progress (see RECOVERY_STOP,
+	 * dlm_recovery_stopped()) and prevents any new locks from being
+	 * processed (see RUNNING, dlm_locking_stopped()).
+	 */
+
+	spin_lock(&ls->ls_recover_lock);
+	set_bit(LSFL_RECOVERY_STOP, &ls->ls_flags);
+	new = test_and_clear_bit(LSFL_RUNNING, &ls->ls_flags);
+	ls->ls_recover_seq++;
+	spin_unlock(&ls->ls_recover_lock);
+
+	/*
+	 * This in_recovery lock does two things:
+	 *
+	 * 1) Keeps this function from returning until all threads are out
+	 *    of locking routines and locking is truely stopped.
+	 * 2) Keeps any new requests from being processed until it's unlocked
+	 *    when recovery is complete.
+	 */
+
+	if (new)
+		down_write(&ls->ls_in_recovery);
+
+	/*
+	 * The recoverd suspend/resume makes sure that dlm_recoverd (if
+	 * running) has noticed the clearing of RUNNING above and quit
+	 * processing the previous recovery.  This will be true for all nodes
+	 * before any nodes start the new recovery.
+	 */
+
+	dlm_recoverd_suspend(ls);
+	ls->ls_recover_status = 0;
+	dlm_recoverd_resume(ls);
+	return 0;
+}
+
+int dlm_ls_start(struct dlm_ls *ls)
+{
+	struct dlm_recover *rv = NULL, *rv_old;
+	int *ids = NULL;
+	int error, count;
+
+	rv = kmalloc(sizeof(struct dlm_recover), GFP_KERNEL);
+	if (!rv)
+		return -ENOMEM;
+	memset(rv, 0, sizeof(struct dlm_recover));
+
+	error = count = dlm_nodeid_list(ls->ls_name, &ids);
+	if (error <= 0)
+		goto fail;
+
+	spin_lock(&ls->ls_recover_lock);
+
+	/* the lockspace needs to be stopped before it can be started */
+
+	if (!dlm_locking_stopped(ls)) {
+		spin_unlock(&ls->ls_recover_lock);
+		log_error(ls, "start ignored: lockspace running");
+		error = -EINVAL;
+		goto fail;
+	}
+
+	rv->nodeids = ids;
+	rv->node_count = count;
+	rv->seq = ++ls->ls_recover_seq;
+	rv_old = ls->ls_recover_args;
+	ls->ls_recover_args = rv;
+	spin_unlock(&ls->ls_recover_lock);
+
+	if (rv_old) {
+		kfree(rv_old->nodeids);
+		kfree(rv_old);
+	}
+
+	dlm_recoverd_kick(ls);
+	return 0;
+
+ fail:
+	kfree(rv);
+	kfree(ids);
+	return error;
+}
+