[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>

fs/dlm/recoverd.c

@@ -0,0 +1,285 @@
+/******************************************************************************
+*******************************************************************************
+**
+**  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 "dlm_internal.h"
+#include "lockspace.h"
+#include "member.h"
+#include "dir.h"
+#include "ast.h"
+#include "recover.h"
+#include "lowcomms.h"
+#include "lock.h"
+#include "requestqueue.h"
+#include "recoverd.h"
+
+
+/* If the start for which we're re-enabling locking (seq) has been superseded
+   by a newer stop (ls_recover_seq), we need to leave locking disabled. */
+
+static int enable_locking(struct dlm_ls *ls, uint64_t seq)
+{
+	int error = -EINTR;
+
+	spin_lock(&ls->ls_recover_lock);
+	if (ls->ls_recover_seq == seq) {
+		set_bit(LSFL_RUNNING, &ls->ls_flags);
+		up_write(&ls->ls_in_recovery);
+		error = 0;
+	}
+	spin_unlock(&ls->ls_recover_lock);
+	return error;
+}
+
+static int ls_recover(struct dlm_ls *ls, struct dlm_recover *rv)
+{
+	unsigned long start;
+	int error, neg = 0;
+
+	log_debug(ls, "recover %"PRIx64"", rv->seq);
+
+	down(&ls->ls_recoverd_active);
+
+	/*
+	 * Suspending and resuming dlm_astd ensures that no lkb's from this ls
+	 * will be processed by dlm_astd during recovery.
+	 */
+
+	dlm_astd_suspend();
+	dlm_astd_resume();
+
+	/*
+	 * This list of root rsb's will be the basis of most of the recovery
+	 * routines.
+	 */
+
+	dlm_create_root_list(ls);
+
+	/*
+	 * Free all the tossed rsb's so we don't have to recover them.
+	 */
+
+	dlm_clear_toss_list(ls);
+
+	/*
+	 * Add or remove nodes from the lockspace's ls_nodes list.
+	 * Also waits for all nodes to complete dlm_recover_members.
+	 */
+
+	error = dlm_recover_members(ls, rv, &neg);
+	if (error) {
+		log_error(ls, "recover_members failed %d", error);
+		goto fail;
+	}
+	start = jiffies;
+
+	/*
+	 * Rebuild our own share of the directory by collecting from all other
+	 * nodes their master rsb names that hash to us.
+	 */
+
+	error = dlm_recover_directory(ls);
+	if (error) {
+		log_error(ls, "recover_directory failed %d", error);
+		goto fail;
+	}
+
+	/*
+	 * Purge directory-related requests that are saved in requestqueue.
+	 * All dir requests from before recovery are invalid now due to the dir
+	 * rebuild and will be resent by the requesting nodes.
+	 */
+
+	dlm_purge_requestqueue(ls);
+
+	/*
+	 * Wait for all nodes to complete directory rebuild.
+	 */
+
+	error = dlm_recover_directory_wait(ls);
+	if (error) {
+		log_error(ls, "recover_directory_wait failed %d", error);
+		goto fail;
+	}
+
+	/*
+	 * We may have outstanding operations that are waiting for a reply from
+	 * a failed node.  Mark these to be resent after recovery.  Unlock and
+	 * cancel ops can just be completed.
+	 */
+
+	dlm_recover_waiters_pre(ls);
+
+	error = dlm_recovery_stopped(ls);
+	if (error)
+		goto fail;
+
+	if (neg || dlm_no_directory(ls)) {
+		/*
+		 * Clear lkb's for departed nodes.
+		 */
+
+		dlm_purge_locks(ls);
+
+		/*
+		 * Get new master nodeid's for rsb's that were mastered on
+		 * departed nodes.
+		 */
+
+		error = dlm_recover_masters(ls);
+		if (error) {
+			log_error(ls, "recover_masters failed %d", error);
+			goto fail;
+		}
+
+		/*
+		 * Send our locks on remastered rsb's to the new masters.
+		 */
+
+		error = dlm_recover_locks(ls);
+		if (error) {
+			log_error(ls, "recover_locks failed %d", error);
+			goto fail;
+		}
+
+		error = dlm_recover_locks_wait(ls);
+		if (error) {
+			log_error(ls, "recover_locks_wait failed %d", error);
+			goto fail;
+		}
+
+		/*
+		 * Finalize state in master rsb's now that all locks can be
+		 * checked.  This includes conversion resolution and lvb
+		 * settings.
+		 */
+
+		dlm_recover_rsbs(ls);
+	}
+
+	dlm_release_root_list(ls);
+
+	dlm_set_recover_status(ls, DLM_RS_DONE);
+	error = dlm_recover_done_wait(ls);
+	if (error) {
+		log_error(ls, "recover_done_wait failed %d", error);
+		goto fail;
+	}
+
+	dlm_clear_members_gone(ls);
+
+	error = enable_locking(ls, rv->seq);
+	if (error) {
+		log_error(ls, "enable_locking failed %d", error);
+		goto fail;
+	}
+
+	error = dlm_process_requestqueue(ls);
+	if (error) {
+		log_error(ls, "process_requestqueue failed %d", error);
+		goto fail;
+	}
+
+	error = dlm_recover_waiters_post(ls);
+	if (error) {
+		log_error(ls, "recover_waiters_post failed %d", error);
+		goto fail;
+	}
+
+	dlm_grant_after_purge(ls);
+
+	dlm_astd_wake();
+
+	log_debug(ls, "recover %"PRIx64" done: %u ms", rv->seq,
+		  jiffies_to_msecs(jiffies - start));
+	up(&ls->ls_recoverd_active);
+
+	return 0;
+
+ fail:
+	dlm_release_root_list(ls);
+	log_debug(ls, "recover %"PRIx64" error %d", rv->seq, error);
+	up(&ls->ls_recoverd_active);
+	return error;
+}
+
+static void do_ls_recovery(struct dlm_ls *ls)
+{
+	struct dlm_recover *rv = NULL;
+
+	spin_lock(&ls->ls_recover_lock);
+	rv = ls->ls_recover_args;
+	ls->ls_recover_args = NULL;
+	clear_bit(LSFL_RECOVERY_STOP, &ls->ls_flags);
+	spin_unlock(&ls->ls_recover_lock);
+
+	if (rv) {
+		ls_recover(ls, rv);
+		kfree(rv->nodeids);
+		kfree(rv);
+	}
+}
+
+static int dlm_recoverd(void *arg)
+{
+	struct dlm_ls *ls;
+
+	ls = dlm_find_lockspace_local(arg);
+
+	while (!kthread_should_stop()) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		if (!test_bit(LSFL_WORK, &ls->ls_flags))
+			schedule();
+		set_current_state(TASK_RUNNING);
+
+		if (test_and_clear_bit(LSFL_WORK, &ls->ls_flags))
+			do_ls_recovery(ls);
+	}
+
+	dlm_put_lockspace(ls);
+	return 0;
+}
+
+void dlm_recoverd_kick(struct dlm_ls *ls)
+{
+	set_bit(LSFL_WORK, &ls->ls_flags);
+	wake_up_process(ls->ls_recoverd_task);
+}
+
+int dlm_recoverd_start(struct dlm_ls *ls)
+{
+	struct task_struct *p;
+	int error = 0;
+
+	p = kthread_run(dlm_recoverd, ls, "dlm_recoverd");
+	if (IS_ERR(p))
+		error = PTR_ERR(p);
+	else
+                ls->ls_recoverd_task = p;
+	return error;
+}
+
+void dlm_recoverd_stop(struct dlm_ls *ls)
+{
+	kthread_stop(ls->ls_recoverd_task);
+}
+
+void dlm_recoverd_suspend(struct dlm_ls *ls)
+{
+	down(&ls->ls_recoverd_active);
+}
+
+void dlm_recoverd_resume(struct dlm_ls *ls)
+{
+	up(&ls->ls_recoverd_active);
+}
+