text: /* -*- mode: c; c-basic-offset: 8; -*-
   * vim: noexpandtab sw=8 ts=8 sts=0:
   *
   * dlmlock.c
   *
   * underlying calls for lock creation
   *
   * 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/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"
  
  #include "dlmconvert.h"
  
  #define MLOG_MASK_PREFIX ML_DLM
  #include "cluster/masklog.h"
  
  static struct kmem_cache *dlm_lock_cache;
  
  static DEFINE_SPINLOCK(dlm_cookie_lock);
  static u64 dlm_next_cookie = 1;
  
  static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
  					       struct dlm_lock_resource *res,
  					       struct dlm_lock *lock, int flags);
  static void dlm_init_lock(struct dlm_lock *newlock, int type,
  			  u8 node, u64 cookie);
  static void dlm_lock_release(struct kref *kref);
  static void dlm_lock_detach_lockres(struct dlm_lock *lock);
  
  int dlm_init_lock_cache(void)
  {
  	dlm_lock_cache = kmem_cache_create("o2dlm_lock",
  					   sizeof(struct dlm_lock),
  					   0, SLAB_HWCACHE_ALIGN, NULL);
  	if (dlm_lock_cache == NULL)
  		return -ENOMEM;
  	return 0;
  }
  
  void dlm_destroy_lock_cache(void)
  {
  	if (dlm_lock_cache)
  		kmem_cache_destroy(dlm_lock_cache);
  }
  
  /* Tell us whether we can grant a new lock request.
   * locking:
   *   caller needs:  res->spinlock
   *   taken:         none
   *   held on exit:  none
   * returns: 1 if the lock can be granted, 0 otherwise.
   */
  static int dlm_can_grant_new_lock(struct dlm_lock_resource *res,
  				  struct dlm_lock *lock)
  {
  	struct dlm_lock *tmplock;
  
  	list_for_each_entry(tmplock, &res->granted, list) {
  		if (!dlm_lock_compatible(tmplock->ml.type, lock->ml.type))
  			return 0;
  	}
  
  	list_for_each_entry(tmplock, &res->converting, list) {
  		if (!dlm_lock_compatible(tmplock->ml.type, lock->ml.type))
  			return 0;
  		if (!dlm_lock_compatible(tmplock->ml.convert_type,
  					 lock->ml.type))
  			return 0;
  	}
  
  	return 1;
  }
  
  /* performs lock creation at the lockres master site
   * locking:
   *   caller needs:  none
   *   taken:         takes and drops res->spinlock
   *   held on exit:  none
   * returns: DLM_NORMAL, DLM_NOTQUEUED
   */
  static enum dlm_status dlmlock_master(struct dlm_ctxt *dlm,
  				      struct dlm_lock_resource *res,
  				      struct dlm_lock *lock, int flags)
  {
  	int call_ast = 0, kick_thread = 0;
  	enum dlm_status status = DLM_NORMAL;
  
  	mlog(0, "type=%d\n", lock->ml.type);
  
  	spin_lock(&res->spinlock);
  	/* if called from dlm_create_lock_handler, need to
  	 * ensure it will not sleep in dlm_wait_on_lockres */
  	status = __dlm_lockres_state_to_status(res);
  	if (status != DLM_NORMAL &&
  	    lock->ml.node != dlm->node_num) {
  		/* erf.  state changed after lock was dropped. */
  		spin_unlock(&res->spinlock);
  		dlm_error(status);
  		return status;
  	}
  	__dlm_wait_on_lockres(res);
  	__dlm_lockres_reserve_ast(res);
  
  	if (dlm_can_grant_new_lock(res, lock)) {
  		mlog(0, "I can grant this lock right away\n");
  		/* got it right away */
  		lock->lksb->status = DLM_NORMAL;
  		status = DLM_NORMAL;
  		dlm_lock_get(lock);
  		list_add_tail(&lock->list, &res->granted);
  
  		/* for the recovery lock, we can't allow the ast
  		 * to be queued since the dlmthread is already
  		 * frozen.  but the recovery lock is always locked
  		 * with LKM_NOQUEUE so we do not need the ast in
  		 * this special case */
  		if (!dlm_is_recovery_lock(res->lockname.name,
  					  res->lockname.len)) {
  			kick_thread = 1;
  			call_ast = 1;
  		} else {
  			mlog(0, "%s: returning DLM_NORMAL to "
  			     "node %u for reco lock\n", dlm->name,
  			     lock->ml.node);
  		}
  	} else {
  		/* for NOQUEUE request, unless we get the
  		 * lock right away, return DLM_NOTQUEUED */
  		if (flags & LKM_NOQUEUE) {
  			status = DLM_NOTQUEUED;
  			if (dlm_is_recovery_lock(res->lockname.name,
  						 res->lockname.len)) {
  				mlog(0, "%s: returning NOTQUEUED to "
  				     "node %u for reco lock\n", dlm->name,
  				     lock->ml.node);
  			}
  		} else {
  			status = DLM_NORMAL;
  			dlm_lock_get(lock);
  			list_add_tail(&lock->list, &res->blocked);
  			kick_thread = 1;
  		}
  	}
  
  	spin_unlock(&res->spinlock);
  	wake_up(&res->wq);
  
  	/* either queue the ast or release it */
  	if (call_ast)
  		dlm_queue_ast(dlm, lock);
  	else
  		dlm_lockres_release_ast(dlm, res);
  
  	dlm_lockres_calc_usage(dlm, res);
  	if (kick_thread)
  		dlm_kick_thread(dlm, res);
  
  	return status;
  }
  
  void dlm_revert_pending_lock(struct dlm_lock_resource *res,
  			     struct dlm_lock *lock)
  {
  	/* remove from local queue if it failed */
  	list_del_init(&lock->list);
  	lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
  }
  
  
  /*
   * locking:
   *   caller needs:  none
   *   taken:         takes and drops res->spinlock
   *   held on exit:  none
   * returns: DLM_DENIED, DLM_RECOVERING, or net status
   */
  static enum dlm_status dlmlock_remote(struct dlm_ctxt *dlm,
  				      struct dlm_lock_resource *res,
  				      struct dlm_lock *lock, int flags)
  {
  	enum dlm_status status = DLM_DENIED;
  	int lockres_changed = 1;
  
  	mlog(0, "type=%d, lockres %.*s, flags = 0x%x\n",
  	     lock->ml.type, res->lockname.len,
  	     res->lockname.name, flags);
  
  	/*
  	 * Wait if resource is getting recovered, remastered, etc.
  	 * If the resource was remastered and new owner is self, then exit.
  	 */
  	spin_lock(&res->spinlock);
  	__dlm_wait_on_lockres(res);
  	if (res->owner == dlm->node_num) {
  		spin_unlock(&res->spinlock);
  		return DLM_RECOVERING;
  	}
  	res->state |= DLM_LOCK_RES_IN_PROGRESS;
  
  	/* add lock to local (secondary) queue */
  	dlm_lock_get(lock);
  	list_add_tail(&lock->list, &res->blocked);
  	lock->lock_pending = 1;
  	spin_unlock(&res->spinlock);
  
  	/* spec seems to say that you will get DLM_NORMAL when the lock
  	 * has been queued, meaning we need to wait for a reply here. */
  	status = dlm_send_remote_lock_request(dlm, res, lock, flags);
  
  	spin_lock(&res->spinlock);
  	res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
  	lock->lock_pending = 0;
  	if (status != DLM_NORMAL) {
  		if (status == DLM_RECOVERING &&
  		    dlm_is_recovery_lock(res->lockname.name,
  					 res->lockname.len)) {
  			/* recovery lock was mastered by dead node.
  			 * we need to have calc_usage shoot down this
  			 * lockres and completely remaster it. */
  			mlog(0, "%s: recovery lock was owned by "
  			     "dead node %u, remaster it now.\n",
  			     dlm->name, res->owner);
  		} else if (status != DLM_NOTQUEUED) {
  			/*
  			 * DO NOT call calc_usage, as this would unhash
  			 * the remote lockres before we ever get to use
  			 * it.  treat as if we never made any change to
  			 * the lockres.
  			 */
  			lockres_changed = 0;
  			dlm_error(status);
  		}
  		dlm_revert_pending_lock(res, lock);
  		dlm_lock_put(lock);
  	} else if (dlm_is_recovery_lock(res->lockname.name,
  					res->lockname.len)) {
  		/* special case for the $RECOVERY lock.
  		 * there will never be an AST delivered to put
  		 * this lock on the proper secondary queue
  		 * (granted), so do it manually. */
  		mlog(0, "%s: $RECOVERY lock for this node (%u) is "
  		     "mastered by %u; got lock, manually granting (no ast)\n",
  		     dlm->name, dlm->node_num, res->owner);
  		list_move_tail(&lock->list, &res->granted);
  	}
  	spin_unlock(&res->spinlock);
  
  	if (lockres_changed)
  		dlm_lockres_calc_usage(dlm, res);
  
  	wake_up(&res->wq);
  	return status;
  }
  
  
  /* for remote lock creation.
   * locking:
   *   caller needs:  none, but need res->state & DLM_LOCK_RES_IN_PROGRESS
   *   taken:         none
   *   held on exit:  none
   * returns: DLM_NOLOCKMGR, or net status
   */
  static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
  					       struct dlm_lock_resource *res,
  					       struct dlm_lock *lock, int flags)
  {
  	struct dlm_create_lock create;
  	int tmpret, status = 0;
  	enum dlm_status ret;
  
  	memset(&create, 0, sizeof(create));
  	create.node_idx = dlm->node_num;
  	create.requested_type = lock->ml.type;
  	create.cookie = lock->ml.cookie;
  	create.namelen = res->lockname.len;
  	create.flags = cpu_to_be32(flags);
  	memcpy(create.name, res->lockname.name, create.namelen);
  
  	tmpret = o2net_send_message(DLM_CREATE_LOCK_MSG, dlm->key, &create,
  				    sizeof(create), res->owner, &status);
  	if (tmpret >= 0) {
  		ret = status;
  		if (ret == DLM_REJECTED) {
  			mlog(ML_ERROR, "%s: res %.*s, Stale lockres no longer "
  			     "owned by node %u. That node is coming back up "
  			     "currently.\n", dlm->name, create.namelen,
  			     create.name, res->owner);
  			dlm_print_one_lock_resource(res);
  			BUG();
  		}
  	} else {
  		mlog(ML_ERROR, "%s: res %.*s, Error %d send CREATE LOCK to "
  		     "node %u\n", dlm->name, create.namelen, create.name,
  		     tmpret, res->owner);
  		if (dlm_is_host_down(tmpret))
  			ret = DLM_RECOVERING;
  		else
  			ret = dlm_err_to_dlm_status(tmpret);
  	}
  
  	return ret;
  }
  
  void dlm_lock_get(struct dlm_lock *lock)
  {
  	kref_get(&lock->lock_refs);
  }
  
  void dlm_lock_put(struct dlm_lock *lock)
  {
  	kref_put(&lock->lock_refs, dlm_lock_release);
  }
  
  static void dlm_lock_release(struct kref *kref)
  {
  	struct dlm_lock *lock;
  
  	lock = container_of(kref, struct dlm_lock, lock_refs);
  
  	BUG_ON(!list_empty(&lock->list));
  	BUG_ON(!list_empty(&lock->ast_list));
  	BUG_ON(!list_empty(&lock->bast_list));
  	BUG_ON(lock->ast_pending);
  	BUG_ON(lock->bast_pending);
  
  	dlm_lock_detach_lockres(lock);
  
  	if (lock->lksb_kernel_allocated) {
  		mlog(0, "freeing kernel-allocated lksb\n");
  		kfree(lock->lksb);
  	}
  	kmem_cache_free(dlm_lock_cache, lock);
  }
  
  /* associate a lock with it's lockres, getting a ref on the lockres */
  void dlm_lock_attach_lockres(struct dlm_lock *lock,
  			     struct dlm_lock_resource *res)
  {
  	dlm_lockres_get(res);
  	lock->lockres = res;
  }
  
  /* drop ref on lockres, if there is still one associated with lock */
  static void dlm_lock_detach_lockres(struct dlm_lock *lock)
  {
  	struct dlm_lock_resource *res;
  
  	res = lock->lockres;
  	if (res) {
  		lock->lockres = NULL;
  		mlog(0, "removing lock's lockres reference\n");
  		dlm_lockres_put(res);
  	}
  }
  
  static void dlm_init_lock(struct dlm_lock *newlock, int type,
  			  u8 node, u64 cookie)
  {
  	INIT_LIST_HEAD(&newlock->list);
  	INIT_LIST_HEAD(&newlock->ast_list);
  	INIT_LIST_HEAD(&newlock->bast_list);
  	spin_lock_init(&newlock->spinlock);
  	newlock->ml.type = type;
  	newlock->ml.convert_type = LKM_IVMODE;
  	newlock->ml.highest_blocked = LKM_IVMODE;
  	newlock->ml.node = node;
  	newlock->ml.pad1 = 0;
  	newlock->ml.list = 0;
  	newlock->ml.flags = 0;
  	newlock->ast = NULL;
  	newlock->bast = NULL;
  	newlock->astdata = NULL;
  	newlock->ml.cookie = cpu_to_be64(cookie);
  	newlock->ast_pending = 0;
  	newlock->bast_pending = 0;
  	newlock->convert_pending = 0;
  	newlock->lock_pending = 0;
  	newlock->unlock_pending = 0;
  	newlock->cancel_pending = 0;
  	newlock->lksb_kernel_allocated = 0;
  
  	kref_init(&newlock->lock_refs);
  }
  
  struct dlm_lock * dlm_new_lock(int type, u8 node, u64 cookie,
  			       struct dlm_lockstatus *lksb)
  {
  	struct dlm_lock *lock;
  	int kernel_allocated = 0;
  
  	lock = kmem_cache_zalloc(dlm_lock_cache, GFP_NOFS);
  	if (!lock)
  		return NULL;
  
  	if (!lksb) {
  		/* zero memory only if kernel-allocated */
  		lksb = kzalloc(sizeof(*lksb), GFP_NOFS);
  		if (!lksb) {
  			kmem_cache_free(dlm_lock_cache, lock);
  			return NULL;
  		}
  		kernel_allocated = 1;
  	}
  
  	dlm_init_lock(lock, type, node, cookie);
  	if (kernel_allocated)
  		lock->lksb_kernel_allocated = 1;
  	lock->lksb = lksb;
  	lksb->lockid = lock;
  	return lock;
  }
  
  /* handler for lock creation net message
   * locking:
   *   caller needs:  none
   *   taken:         takes and drops res->spinlock
   *   held on exit:  none
   * returns: DLM_NORMAL, DLM_SYSERR, DLM_IVLOCKID, DLM_NOTQUEUED
   */
  int dlm_create_lock_handler(struct o2net_msg *msg, u32 len, void *data,
  			    void **ret_data)
  {
  	struct dlm_ctxt *dlm = data;
  	struct dlm_create_lock *create = (struct dlm_create_lock *)msg->buf;
  	struct dlm_lock_resource *res = NULL;
  	struct dlm_lock *newlock = NULL;
  	struct dlm_lockstatus *lksb = NULL;
  	enum dlm_status status = DLM_NORMAL;
  	char *name;
  	unsigned int namelen;
  
  	BUG_ON(!dlm);
  
  	if (!dlm_grab(dlm))
  		return DLM_REJECTED;
  
  	name = create->name;
  	namelen = create->namelen;
  	status = DLM_REJECTED;
  	if (!dlm_domain_fully_joined(dlm)) {
  		mlog(ML_ERROR, "Domain %s not fully joined, but node %u is "
  		     "sending a create_lock message for lock %.*s!\n",
  		     dlm->name, create->node_idx, namelen, name);
  		dlm_error(status);
  		goto leave;
  	}
  
  	status = DLM_IVBUFLEN;
  	if (namelen > DLM_LOCKID_NAME_MAX) {
  		dlm_error(status);
  		goto leave;
  	}
  
  	status = DLM_SYSERR;
  	newlock = dlm_new_lock(create->requested_type,
  			       create->node_idx,
  			       be64_to_cpu(create->cookie), NULL);
  	if (!newlock) {
  		dlm_error(status);
  		goto leave;
  	}
  
  	lksb = newlock->lksb;
  
  	if (be32_to_cpu(create->flags) & LKM_GET_LVB) {
  		lksb->flags |= DLM_LKSB_GET_LVB;
  		mlog(0, "set DLM_LKSB_GET_LVB flag\n");
  	}
  
  	status = DLM_IVLOCKID;
  	res = dlm_lookup_lockres(dlm, name, namelen);
  	if (!res) {
  		dlm_error(status);
  		goto leave;
  	}
  
  	spin_lock(&res->spinlock);
  	status = __dlm_lockres_state_to_status(res);
  	spin_unlock(&res->spinlock);
  
  	if (status != DLM_NORMAL) {
  		mlog(0, "lockres recovering/migrating/in-progress\n");
  		goto leave;
  	}
  
  	dlm_lock_attach_lockres(newlock, res);
  
  	status = dlmlock_master(dlm, res, newlock, be32_to_cpu(create->flags));
  leave:
  	if (status != DLM_NORMAL)
  		if (newlock)
  			dlm_lock_put(newlock);
  
  	if (res)
  		dlm_lockres_put(res);
  
  	dlm_put(dlm);
  
  	return status;
  }
  
  
  /* fetch next node-local (u8 nodenum + u56 cookie) into u64 */
  static inline void dlm_get_next_cookie(u8 node_num, u64 *cookie)
  {
  	u64 tmpnode = node_num;
  
  	/* shift single byte of node num into top 8 bits */
  	tmpnode <<= 56;
  
  	spin_lock(&dlm_cookie_lock);
  	*cookie = (dlm_next_cookie | tmpnode);
  	if (++dlm_next_cookie & 0xff00000000000000ull) {
  		mlog(0, "This node's cookie will now wrap!\n");
  		dlm_next_cookie = 1;
  	}
  	spin_unlock(&dlm_cookie_lock);
  }
  
  enum dlm_status dlmlock(struct dlm_ctxt *dlm, int mode,
  			struct dlm_lockstatus *lksb, int flags,
  			const char *name, int namelen, dlm_astlockfunc_t *ast,
  			void *data, dlm_bastlockfunc_t *bast)
  {
  	enum dlm_status status;
  	struct dlm_lock_resource *res = NULL;
  	struct dlm_lock *lock = NULL;
  	int convert = 0, recovery = 0;
  
  	/* yes this function is a mess.
  	 * TODO: clean this up.  lots of common code in the
  	 *       lock and convert paths, especially in the retry blocks */
  	if (!lksb) {
  		dlm_error(DLM_BADARGS);
  		return DLM_BADARGS;
  	}
  
  	status = DLM_BADPARAM;
  	if (mode != LKM_EXMODE && mode != LKM_PRMODE && mode != LKM_NLMODE) {
  		dlm_error(status);
  		goto error;
  	}
  
  	if (flags & ~LKM_VALID_FLAGS) {
  		dlm_error(status);
  		goto error;
  	}
  
  	convert = (flags & LKM_CONVERT);
  	recovery = (flags & LKM_RECOVERY);
  
  	if (recovery &&
  	    (!dlm_is_recovery_lock(name, namelen) || convert) ) {
  		dlm_error(status);
  		goto error;
  	}
  	if (convert && (flags & LKM_LOCAL)) {
  		mlog(ML_ERROR, "strange LOCAL convert request!\n");
  		goto error;
  	}
  
  	if (convert) {
  		/* CONVERT request */
  
  		/* if converting, must pass in a valid dlm_lock */
  		lock = lksb->lockid;
  		if (!lock) {
  			mlog(ML_ERROR, "NULL lock pointer in convert "
  			     "request\n");
  			goto error;
  		}
  
  		res = lock->lockres;
  		if (!res) {
  			mlog(ML_ERROR, "NULL lockres pointer in convert "
  			     "request\n");
  			goto error;
  		}
  		dlm_lockres_get(res);
  
  		/* XXX: for ocfs2 purposes, the ast/bast/astdata/lksb are
  	 	 * static after the original lock call.  convert requests will
  		 * ensure that everything is the same, or return DLM_BADARGS.
  	 	 * this means that DLM_DENIED_NOASTS will never be returned.
  	 	 */
  		if (lock->lksb != lksb || lock->ast != ast ||
  		    lock->bast != bast || lock->astdata != data) {
  			status = DLM_BADARGS;
  			mlog(ML_ERROR, "new args:  lksb=%p, ast=%p, bast=%p, "
  			     "astdata=%p\n", lksb, ast, bast, data);
  			mlog(ML_ERROR, "orig args: lksb=%p, ast=%p, bast=%p, "
  			     "astdata=%p\n", lock->lksb, lock->ast,
  			     lock->bast, lock->astdata);
  			goto error;
  		}
  retry_convert:
  		dlm_wait_for_recovery(dlm);
  
  		if (res->owner == dlm->node_num)
  			status = dlmconvert_master(dlm, res, lock, flags, mode);
  		else
  			status = dlmconvert_remote(dlm, res, lock, flags, mode);
  		if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
  		    status == DLM_FORWARD) {
  			/* for now, see how this works without sleeping
  			 * and just retry right away.  I suspect the reco
  			 * or migration will complete fast enough that
  			 * no waiting will be necessary */
  			mlog(0, "retrying convert with migration/recovery/"
  			     "in-progress\n");
  			msleep(100);
  			goto retry_convert;
  		}
  	} else {
  		u64 tmpcookie;
  
  		/* LOCK request */
  		status = DLM_BADARGS;
  		if (!name) {
  			dlm_error(status);
  			goto error;
  		}
  
  		status = DLM_IVBUFLEN;
  		if (namelen > DLM_LOCKID_NAME_MAX || namelen < 1) {
  			dlm_error(status);
  			goto error;
  		}
  
  		dlm_get_next_cookie(dlm->node_num, &tmpcookie);
  		lock = dlm_new_lock(mode, dlm->node_num, tmpcookie, lksb);
  		if (!lock) {
  			dlm_error(status);
  			goto error;
  		}
  
  		if (!recovery)
  			dlm_wait_for_recovery(dlm);
  
  		/* find or create the lock resource */
  		res = dlm_get_lock_resource(dlm, name, namelen, flags);
  		if (!res) {
  			status = DLM_IVLOCKID;
  			dlm_error(status);
  			goto error;
  		}
  
  		mlog(0, "type=%d, flags = 0x%x\n", mode, flags);
  		mlog(0, "creating lock: lock=%p res=%p\n", lock, res);
  
  		dlm_lock_attach_lockres(lock, res);
  		lock->ast = ast;
  		lock->bast = bast;
  		lock->astdata = data;
  
  retry_lock:
  		if (flags & LKM_VALBLK) {
  			mlog(0, "LKM_VALBLK passed by caller\n");
  
  			/* LVB requests for non PR, PW or EX locks are
  			 * ignored. */
  			if (mode < LKM_PRMODE)
  				flags &= ~LKM_VALBLK;
  			else {
  				flags |= LKM_GET_LVB;
  				lock->lksb->flags |= DLM_LKSB_GET_LVB;
  			}
  		}
  
  		if (res->owner == dlm->node_num)
  			status = dlmlock_master(dlm, res, lock, flags);
  		else
  			status = dlmlock_remote(dlm, res, lock, flags);
  
  		if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
  		    status == DLM_FORWARD) {
  			msleep(100);
  			if (recovery) {
  				if (status != DLM_RECOVERING)
  					goto retry_lock;
  				/* wait to see the node go down, then
  				 * drop down and allow the lockres to
  				 * get cleaned up.  need to remaster. */
  				dlm_wait_for_node_death(dlm, res->owner,
  						DLM_NODE_DEATH_WAIT_MAX);
  			} else {
  				dlm_wait_for_recovery(dlm);
  				goto retry_lock;
  			}
  		}
  
  		/* Inflight taken in dlm_get_lock_resource() is dropped here */
  		spin_lock(&res->spinlock);
  		dlm_lockres_drop_inflight_ref(dlm, res);
  		spin_unlock(&res->spinlock);
  
  		dlm_lockres_calc_usage(dlm, res);
  		dlm_kick_thread(dlm, res);
  
  		if (status != DLM_NORMAL) {
  			lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
  			if (status != DLM_NOTQUEUED)
  				dlm_error(status);
  			goto error;
  		}
  	}
  
  error:
  	if (status != DLM_NORMAL) {
  		if (lock && !convert)
  			dlm_lock_put(lock);
  		// this is kind of unnecessary
  		lksb->status = status;
  	}
  
  	/* put lockres ref from the convert path
  	 * or from dlm_get_lock_resource */
  	if (res)
  		dlm_lockres_put(res);
  
  	return status;
  }
  EXPORT_SYMBOL_GPL(dlmlock);
  