[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>
This commit is contained in:
David Teigland
committed by
Steven Whitehouse
Steven Whitehouse
parent
e473142070
commit
e7fd41792f
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/******************************************************************************
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*******************************************************************************
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**
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** Copyright (C) 2005 Red Hat, Inc. All rights reserved.
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**
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** This copyrighted material is made available to anyone wishing to use,
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** modify, copy, or redistribute it subject to the terms and conditions
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** of the GNU General Public License v.2.
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**
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*******************************************************************************
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******************************************************************************/
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#include "dlm_internal.h"
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#include "lockspace.h"
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#include "member.h"
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#include "recoverd.h"
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#include "recover.h"
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#include "lowcomms.h"
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#include "rcom.h"
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#include "config.h"
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/*
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* Following called by dlm_recoverd thread
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*/
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static void add_ordered_member(struct dlm_ls *ls, struct dlm_member *new)
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{
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struct dlm_member *memb = NULL;
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struct list_head *tmp;
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struct list_head *newlist = &new->list;
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struct list_head *head = &ls->ls_nodes;
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list_for_each(tmp, head) {
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memb = list_entry(tmp, struct dlm_member, list);
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if (new->nodeid < memb->nodeid)
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break;
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}
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if (!memb)
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list_add_tail(newlist, head);
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else {
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/* FIXME: can use list macro here */
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newlist->prev = tmp->prev;
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newlist->next = tmp;
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tmp->prev->next = newlist;
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tmp->prev = newlist;
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}
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}
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static int dlm_add_member(struct dlm_ls *ls, int nodeid)
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{
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struct dlm_member *memb;
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int w;
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memb = kmalloc(sizeof(struct dlm_member), GFP_KERNEL);
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if (!memb)
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return -ENOMEM;
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w = dlm_node_weight(ls->ls_name, nodeid);
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if (w < 0)
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return w;
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memb->nodeid = nodeid;
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memb->weight = w;
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add_ordered_member(ls, memb);
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ls->ls_num_nodes++;
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return 0;
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}
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static void dlm_remove_member(struct dlm_ls *ls, struct dlm_member *memb)
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{
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list_move(&memb->list, &ls->ls_nodes_gone);
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ls->ls_num_nodes--;
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}
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static int dlm_is_member(struct dlm_ls *ls, int nodeid)
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{
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struct dlm_member *memb;
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list_for_each_entry(memb, &ls->ls_nodes, list) {
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if (memb->nodeid == nodeid)
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return TRUE;
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}
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return FALSE;
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}
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int dlm_is_removed(struct dlm_ls *ls, int nodeid)
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{
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struct dlm_member *memb;
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list_for_each_entry(memb, &ls->ls_nodes_gone, list) {
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if (memb->nodeid == nodeid)
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return TRUE;
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}
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return FALSE;
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}
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static void clear_memb_list(struct list_head *head)
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{
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struct dlm_member *memb;
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while (!list_empty(head)) {
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memb = list_entry(head->next, struct dlm_member, list);
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list_del(&memb->list);
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kfree(memb);
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}
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}
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void dlm_clear_members(struct dlm_ls *ls)
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{
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clear_memb_list(&ls->ls_nodes);
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ls->ls_num_nodes = 0;
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}
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void dlm_clear_members_gone(struct dlm_ls *ls)
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{
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clear_memb_list(&ls->ls_nodes_gone);
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}
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static void make_member_array(struct dlm_ls *ls)
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{
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struct dlm_member *memb;
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int i, w, x = 0, total = 0, all_zero = 0, *array;
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kfree(ls->ls_node_array);
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ls->ls_node_array = NULL;
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list_for_each_entry(memb, &ls->ls_nodes, list) {
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if (memb->weight)
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total += memb->weight;
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}
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/* all nodes revert to weight of 1 if all have weight 0 */
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if (!total) {
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total = ls->ls_num_nodes;
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all_zero = 1;
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}
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ls->ls_total_weight = total;
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array = kmalloc(sizeof(int) * total, GFP_KERNEL);
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if (!array)
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return;
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list_for_each_entry(memb, &ls->ls_nodes, list) {
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if (!all_zero && !memb->weight)
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continue;
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if (all_zero)
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w = 1;
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else
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w = memb->weight;
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DLM_ASSERT(x < total, printk("total %d x %d\n", total, x););
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for (i = 0; i < w; i++)
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array[x++] = memb->nodeid;
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}
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ls->ls_node_array = array;
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}
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/* send a status request to all members just to establish comms connections */
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static void ping_members(struct dlm_ls *ls)
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{
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struct dlm_member *memb;
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list_for_each_entry(memb, &ls->ls_nodes, list)
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dlm_rcom_status(ls, memb->nodeid);
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}
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int dlm_recover_members(struct dlm_ls *ls, struct dlm_recover *rv, int *neg_out)
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{
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struct dlm_member *memb, *safe;
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int i, error, found, pos = 0, neg = 0, low = -1;
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/* move departed members from ls_nodes to ls_nodes_gone */
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list_for_each_entry_safe(memb, safe, &ls->ls_nodes, list) {
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found = FALSE;
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for (i = 0; i < rv->node_count; i++) {
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if (memb->nodeid == rv->nodeids[i]) {
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found = TRUE;
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break;
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}
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}
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if (!found) {
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neg++;
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dlm_remove_member(ls, memb);
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log_debug(ls, "remove member %d", memb->nodeid);
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}
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}
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/* add new members to ls_nodes */
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for (i = 0; i < rv->node_count; i++) {
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if (dlm_is_member(ls, rv->nodeids[i]))
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continue;
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dlm_add_member(ls, rv->nodeids[i]);
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pos++;
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log_debug(ls, "add member %d", rv->nodeids[i]);
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}
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list_for_each_entry(memb, &ls->ls_nodes, list) {
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if (low == -1 || memb->nodeid < low)
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low = memb->nodeid;
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}
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ls->ls_low_nodeid = low;
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make_member_array(ls);
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dlm_set_recover_status(ls, DLM_RS_NODES);
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*neg_out = neg;
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ping_members(ls);
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error = dlm_recover_members_wait(ls);
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log_debug(ls, "total members %d", ls->ls_num_nodes);
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return error;
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}
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/*
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* Following called from lockspace.c
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*/
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int dlm_ls_stop(struct dlm_ls *ls)
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{
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int new;
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/*
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* A stop cancels any recovery that's in progress (see RECOVERY_STOP,
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* dlm_recovery_stopped()) and prevents any new locks from being
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* processed (see RUNNING, dlm_locking_stopped()).
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*/
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spin_lock(&ls->ls_recover_lock);
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set_bit(LSFL_RECOVERY_STOP, &ls->ls_flags);
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new = test_and_clear_bit(LSFL_RUNNING, &ls->ls_flags);
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ls->ls_recover_seq++;
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spin_unlock(&ls->ls_recover_lock);
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/*
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* This in_recovery lock does two things:
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*
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* 1) Keeps this function from returning until all threads are out
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* of locking routines and locking is truely stopped.
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* 2) Keeps any new requests from being processed until it's unlocked
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* when recovery is complete.
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*/
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if (new)
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down_write(&ls->ls_in_recovery);
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/*
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* The recoverd suspend/resume makes sure that dlm_recoverd (if
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* running) has noticed the clearing of RUNNING above and quit
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* processing the previous recovery. This will be true for all nodes
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* before any nodes start the new recovery.
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*/
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dlm_recoverd_suspend(ls);
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ls->ls_recover_status = 0;
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dlm_recoverd_resume(ls);
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return 0;
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}
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int dlm_ls_start(struct dlm_ls *ls)
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{
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struct dlm_recover *rv = NULL, *rv_old;
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int *ids = NULL;
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int error, count;
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rv = kmalloc(sizeof(struct dlm_recover), GFP_KERNEL);
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if (!rv)
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return -ENOMEM;
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memset(rv, 0, sizeof(struct dlm_recover));
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error = count = dlm_nodeid_list(ls->ls_name, &ids);
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if (error <= 0)
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goto fail;
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spin_lock(&ls->ls_recover_lock);
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/* the lockspace needs to be stopped before it can be started */
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if (!dlm_locking_stopped(ls)) {
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spin_unlock(&ls->ls_recover_lock);
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log_error(ls, "start ignored: lockspace running");
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error = -EINVAL;
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goto fail;
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}
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rv->nodeids = ids;
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rv->node_count = count;
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rv->seq = ++ls->ls_recover_seq;
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rv_old = ls->ls_recover_args;
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ls->ls_recover_args = rv;
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spin_unlock(&ls->ls_recover_lock);
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if (rv_old) {
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kfree(rv_old->nodeids);
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kfree(rv_old);
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}
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dlm_recoverd_kick(ls);
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return 0;
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fail:
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kfree(rv);
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kfree(ids);
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return error;
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}
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