dlmunlock.c

linux2.6.16版本

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * dlmunlock.c
 *
 * underlying calls for unlocking locks
 *
 * Copyright (C) 2004 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 *
 */


#include <linux/module.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/utsname.h>
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/random.h>
#include <linux/blkdev.h>
#include <linux/socket.h>
#include <linux/inet.h>
#include <linux/spinlock.h>
#include <linux/delay.h>

#include "cluster/heartbeat.h"
#include "cluster/nodemanager.h"
#include "cluster/tcp.h"

#include "dlmapi.h"
#include "dlmcommon.h"

#define MLOG_MASK_PREFIX ML_DLM
#include "cluster/masklog.h"

#define DLM_UNLOCK_FREE_LOCK           0x00000001
#define DLM_UNLOCK_CALL_AST            0x00000002
#define DLM_UNLOCK_REMOVE_LOCK         0x00000004
#define DLM_UNLOCK_REGRANT_LOCK        0x00000008
#define DLM_UNLOCK_CLEAR_CONVERT_TYPE  0x00000010


static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
					      struct dlm_lock_resource *res,
					      struct dlm_lock *lock,
					      struct dlm_lockstatus *lksb,
					      int *actions);
static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
					      struct dlm_lock_resource *res,
					      struct dlm_lock *lock,
					      struct dlm_lockstatus *lksb,
					      int *actions);

static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
						 struct dlm_lock_resource *res,
						 struct dlm_lock *lock,
						 struct dlm_lockstatus *lksb,
						 int flags,
						 u8 owner);


/*
 * according to the spec:
 * http://opendlm.sourceforge.net/cvsmirror/opendlm/docs/dlmbook_final.pdf
 *
 *  flags & LKM_CANCEL != 0: must be converting or blocked
 *  flags & LKM_CANCEL == 0: must be granted
 *
 * So to unlock a converting lock, you must first cancel the
 * convert (passing LKM_CANCEL in flags), then call the unlock
 * again (with no LKM_CANCEL in flags).
 */


/*
 * locking:
 *   caller needs:  none
 *   taken:         res->spinlock and lock->spinlock taken and dropped
 *   held on exit:  none
 * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
 * all callers should have taken an extra ref on lock coming in
 */
static enum dlm_status dlmunlock_common(struct dlm_ctxt *dlm,
					struct dlm_lock_resource *res,
					struct dlm_lock *lock,
					struct dlm_lockstatus *lksb,
					int flags, int *call_ast,
					int master_node)
{
	enum dlm_status status;
	int actions = 0;
	int in_use;
        u8 owner;

	mlog(0, "master_node = %d, valblk = %d\n", master_node,
	     flags & LKM_VALBLK);

	if (master_node)
		BUG_ON(res->owner != dlm->node_num);
	else
		BUG_ON(res->owner == dlm->node_num);

	spin_lock(&dlm->spinlock);
	/* We want to be sure that we're not freeing a lock
	 * that still has AST's pending... */
	in_use = !list_empty(&lock->ast_list);
	spin_unlock(&dlm->spinlock);
	if (in_use) {
	       mlog(ML_ERROR, "lockres %.*s: Someone is calling dlmunlock "
		    "while waiting for an ast!", res->lockname.len,
		    res->lockname.name);
		return DLM_BADPARAM;
	}

	spin_lock(&res->spinlock);
	if (res->state & DLM_LOCK_RES_IN_PROGRESS) {
		if (master_node) {
			mlog(ML_ERROR, "lockres in progress!\n");
			spin_unlock(&res->spinlock);
			return DLM_FORWARD;
		}
		/* ok for this to sleep if not in a network handler */
		__dlm_wait_on_lockres(res);
		res->state |= DLM_LOCK_RES_IN_PROGRESS;
	}
	spin_lock(&lock->spinlock);

	if (res->state & DLM_LOCK_RES_RECOVERING) {
		status = DLM_RECOVERING;
		goto leave;
	}


	/* see above for what the spec says about
	 * LKM_CANCEL and the lock queue state */
	if (flags & LKM_CANCEL)
		status = dlm_get_cancel_actions(dlm, res, lock, lksb, &actions);
	else
		status = dlm_get_unlock_actions(dlm, res, lock, lksb, &actions);

	if (status != DLM_NORMAL)
		goto leave;

	/* By now this has been masked out of cancel requests. */
	if (flags & LKM_VALBLK) {
		/* make the final update to the lvb */
		if (master_node)
			memcpy(res->lvb, lksb->lvb, DLM_LVB_LEN);
		else
			flags |= LKM_PUT_LVB; /* let the send function
					       * handle it. */
	}

	if (!master_node) {
		owner = res->owner;
		/* drop locks and send message */
		if (flags & LKM_CANCEL)
			lock->cancel_pending = 1;
		else
			lock->unlock_pending = 1;
		spin_unlock(&lock->spinlock);
		spin_unlock(&res->spinlock);
		status = dlm_send_remote_unlock_request(dlm, res, lock, lksb,
							flags, owner);
		spin_lock(&res->spinlock);
		spin_lock(&lock->spinlock);
		/* if the master told us the lock was already granted,
		 * let the ast handle all of these actions */
		if (status == DLM_NORMAL &&
		    lksb->status == DLM_CANCELGRANT) {
			actions &= ~(DLM_UNLOCK_REMOVE_LOCK|
				     DLM_UNLOCK_REGRANT_LOCK|
				     DLM_UNLOCK_CLEAR_CONVERT_TYPE);
		} else if (status == DLM_RECOVERING || 
			   status == DLM_MIGRATING || 
			   status == DLM_FORWARD) {
			/* must clear the actions because this unlock
			 * is about to be retried.  cannot free or do
			 * any list manipulation. */
			mlog(0, "%s:%.*s: clearing actions, %s\n",
			     dlm->name, res->lockname.len,
			     res->lockname.name,
			     status==DLM_RECOVERING?"recovering":
			     (status==DLM_MIGRATING?"migrating":
			      "forward"));
			actions = 0;
		}
		if (flags & LKM_CANCEL)
			lock->cancel_pending = 0;
		else
			lock->unlock_pending = 0;

	}

	/* get an extra ref on lock.  if we are just switching
	 * lists here, we dont want the lock to go away. */
	dlm_lock_get(lock);

	if (actions & DLM_UNLOCK_REMOVE_LOCK) {
		list_del_init(&lock->list);
		dlm_lock_put(lock);
	}
	if (actions & DLM_UNLOCK_REGRANT_LOCK) {
		dlm_lock_get(lock);
		list_add_tail(&lock->list, &res->granted);
	}
	if (actions & DLM_UNLOCK_CLEAR_CONVERT_TYPE) {
		mlog(0, "clearing convert_type at %smaster node\n",
		     master_node ? "" : "non-");
		lock->ml.convert_type = LKM_IVMODE;
	}

	/* remove the extra ref on lock */
	dlm_lock_put(lock);

leave:
	res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
	if (!dlm_lock_on_list(&res->converting, lock))
		BUG_ON(lock->ml.convert_type != LKM_IVMODE);
	else
		BUG_ON(lock->ml.convert_type == LKM_IVMODE);
	spin_unlock(&lock->spinlock);
	spin_unlock(&res->spinlock);
	wake_up(&res->wq);

	/* let the caller's final dlm_lock_put handle the actual kfree */
	if (actions & DLM_UNLOCK_FREE_LOCK) {
		/* this should always be coupled with list removal */
		BUG_ON(!(actions & DLM_UNLOCK_REMOVE_LOCK));
		mlog(0, "lock %"MLFu64" should be gone now! refs=%d\n",
		     lock->ml.cookie, atomic_read(&lock->lock_refs.refcount)-1);
		dlm_lock_put(lock);
	}
	if (actions & DLM_UNLOCK_CALL_AST)
		*call_ast = 1;

	/* if cancel or unlock succeeded, lvb work is done */
	if (status == DLM_NORMAL)
		lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);

	return status;
}

void dlm_commit_pending_unlock(struct dlm_lock_resource *res,
			       struct dlm_lock *lock)
{
	/* leave DLM_LKSB_PUT_LVB on the lksb so any final
	 * update of the lvb will be sent to the new master */
	list_del_init(&lock->list);
}

void dlm_commit_pending_cancel(struct dlm_lock_resource *res,
			       struct dlm_lock *lock)
{
	list_del_init(&lock->list);
	list_add_tail(&lock->list, &res->granted);
	lock->ml.convert_type = LKM_IVMODE;
}


static inline enum dlm_status dlmunlock_master(struct dlm_ctxt *dlm,
					  struct dlm_lock_resource *res,
					  struct dlm_lock *lock,
					  struct dlm_lockstatus *lksb,
					  int flags,
					  int *call_ast)
{
	return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 1);
}

static inline enum dlm_status dlmunlock_remote(struct dlm_ctxt *dlm,
					  struct dlm_lock_resource *res,
					  struct dlm_lock *lock,
					  struct dlm_lockstatus *lksb,
					  int flags, int *call_ast)
{
	return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 0);
}

/*
 * locking:
 *   caller needs:  none
 *   taken:         none
 *   held on exit:  none
 * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
 */
static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
						 struct dlm_lock_resource *res,
						 struct dlm_lock *lock,
						 struct dlm_lockstatus *lksb,
						 int flags,
						 u8 owner)
{
	struct dlm_unlock_lock unlock;
	int tmpret;
	enum dlm_status ret;
	int status = 0;
	struct kvec vec[2];
	size_t veclen = 1;

	mlog_entry("%.*s\n", res->lockname.len, res->lockname.name);

	memset(&unlock, 0, sizeof(unlock));
	unlock.node_idx = dlm->node_num;
	unlock.flags = cpu_to_be32(flags);
	unlock.cookie = lock->ml.cookie;
	unlock.namelen = res->lockname.len;
	memcpy(unlock.name, res->lockname.name, unlock.namelen);

	vec[0].iov_len = sizeof(struct dlm_unlock_lock);
	vec[0].iov_base = &unlock;

	if (flags & LKM_PUT_LVB) {
		/* extra data to send if we are updating lvb */
		vec[1].iov_len = DLM_LVB_LEN;
		vec[1].iov_base = lock->lksb->lvb;
		veclen++;
	}

	tmpret = o2net_send_message_vec(DLM_UNLOCK_LOCK_MSG, dlm->key,
					vec, veclen, owner, &status);
	if (tmpret >= 0) {
		// successfully sent and received
		if (status == DLM_CANCELGRANT)
			ret = DLM_NORMAL;
		else if (status == DLM_FORWARD) {