1 files changed, 819 insertions, 203 deletions

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index bdafb65a523..d9ee1b96549 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -90,6 +90,7 @@ static void __receive_convert_reply(struct dlm_rsb *r, struct dlm_lkb *lkb,
 static int receive_extralen(struct dlm_message *ms);
 static void do_purge(struct dlm_ls *ls, int nodeid, int pid);
 static void del_timeout(struct dlm_lkb *lkb);
+static void toss_rsb(struct kref *kref);
 
 /*
  * Lock compatibilty matrix - thanks Steve
@@ -170,9 +171,11 @@ void dlm_print_lkb(struct dlm_lkb *lkb)
 
 static void dlm_print_rsb(struct dlm_rsb *r)
 {
-	printk(KERN_ERR "rsb: nodeid %d flags %lx first %x rlc %d name %s\n",
-	       r->res_nodeid, r->res_flags, r->res_first_lkid,
-	       r->res_recover_locks_count, r->res_name);
+	printk(KERN_ERR "rsb: nodeid %d master %d dir %d flags %lx first %x "
+	       "rlc %d name %s\n",
+	       r->res_nodeid, r->res_master_nodeid, r->res_dir_nodeid,
+	       r->res_flags, r->res_first_lkid, r->res_recover_locks_count,
+	       r->res_name);
 }
 
 void dlm_dump_rsb(struct dlm_rsb *r)
@@ -327,6 +330,37 @@ static void queue_bast(struct dlm_rsb *r, struct dlm_lkb *lkb, int rqmode)
  * Basic operations on rsb's and lkb's
  */
 
+/* This is only called to add a reference when the code already holds
+   a valid reference to the rsb, so there's no need for locking. */
+
+static inline void hold_rsb(struct dlm_rsb *r)
+{
+	kref_get(&r->res_ref);
+}
+
+void dlm_hold_rsb(struct dlm_rsb *r)
+{
+	hold_rsb(r);
+}
+
+/* When all references to the rsb are gone it's transferred to
+   the tossed list for later disposal. */
+
+static void put_rsb(struct dlm_rsb *r)
+{
+	struct dlm_ls *ls = r->res_ls;
+	uint32_t bucket = r->res_bucket;
+
+	spin_lock(&ls->ls_rsbtbl[bucket].lock);
+	kref_put(&r->res_ref, toss_rsb);
+	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
+}
+
+void dlm_put_rsb(struct dlm_rsb *r)
+{
+	put_rsb(r);
+}
+
 static int pre_rsb_struct(struct dlm_ls *ls)
 {
 	struct dlm_rsb *r1, *r2;
@@ -411,11 +445,10 @@ static int rsb_cmp(struct dlm_rsb *r, const char *name, int nlen)
 }
 
 int dlm_search_rsb_tree(struct rb_root *tree, char *name, int len,
-			unsigned int flags, struct dlm_rsb **r_ret)
+			struct dlm_rsb **r_ret)
 {
 	struct rb_node *node = tree->rb_node;
 	struct dlm_rsb *r;
-	int error = 0;
 	int rc;
 
 	while (node) {
@@ -432,10 +465,8 @@ int dlm_search_rsb_tree(struct rb_root *tree, char *name, int len,
 	return -EBADR;
 
  found:
-	if (r->res_nodeid && (flags & R_MASTER))
-		error = -ENOTBLK;
 	*r_ret = r;
-	return error;
+	return 0;
 }
 
 static int rsb_insert(struct dlm_rsb *rsb, struct rb_root *tree)
@@ -467,124 +498,587 @@ static int rsb_insert(struct dlm_rsb *rsb, struct rb_root *tree)
 	return 0;
 }
 
-static int _search_rsb(struct dlm_ls *ls, char *name, int len, int b,
-		       unsigned int flags, struct dlm_rsb **r_ret)
+/*
+ * Find rsb in rsbtbl and potentially create/add one
+ *
+ * Delaying the release of rsb's has a similar benefit to applications keeping
+ * NL locks on an rsb, but without the guarantee that the cached master value
+ * will still be valid when the rsb is reused.  Apps aren't always smart enough
+ * to keep NL locks on an rsb that they may lock again shortly; this can lead
+ * to excessive master lookups and removals if we don't delay the release.
+ *
+ * Searching for an rsb means looking through both the normal list and toss
+ * list.  When found on the toss list the rsb is moved to the normal list with
+ * ref count of 1; when found on normal list the ref count is incremented.
+ *
+ * rsb's on the keep list are being used locally and refcounted.
+ * rsb's on the toss list are not being used locally, and are not refcounted.
+ *
+ * The toss list rsb's were either
+ * - previously used locally but not any more (were on keep list, then
+ *   moved to toss list when last refcount dropped)
+ * - created and put on toss list as a directory record for a lookup
+ *   (we are the dir node for the res, but are not using the res right now,
+ *   but some other node is)
+ *
+ * The purpose of find_rsb() is to return a refcounted rsb for local use.
+ * So, if the given rsb is on the toss list, it is moved to the keep list
+ * before being returned.
+ *
+ * toss_rsb() happens when all local usage of the rsb is done, i.e. no
+ * more refcounts exist, so the rsb is moved from the keep list to the
+ * toss list.
+ *
+ * rsb's on both keep and toss lists are used for doing a name to master
+ * lookups.  rsb's that are in use locally (and being refcounted) are on
+ * the keep list, rsb's that are not in use locally (not refcounted) and
+ * only exist for name/master lookups are on the toss list.
+ *
+ * rsb's on the toss list who's dir_nodeid is not local can have stale
+ * name/master mappings.  So, remote requests on such rsb's can potentially
+ * return with an error, which means the mapping is stale and needs to
+ * be updated with a new lookup.  (The idea behind MASTER UNCERTAIN and
+ * first_lkid is to keep only a single outstanding request on an rsb
+ * while that rsb has a potentially stale master.)
+ */
+
+static int find_rsb_dir(struct dlm_ls *ls, char *name, int len,
+			uint32_t hash, uint32_t b,
+			int dir_nodeid, int from_nodeid,
+			unsigned int flags, struct dlm_rsb **r_ret)
 {
-	struct dlm_rsb *r;
+	struct dlm_rsb *r = NULL;
+	int our_nodeid = dlm_our_nodeid();
+	int from_local = 0;
+	int from_other = 0;
+	int from_dir = 0;
+	int create = 0;
 	int error;
 
-	error = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].keep, name, len, flags, &r);
-	if (!error) {
-		kref_get(&r->res_ref);
-		goto out;
+	if (flags & R_RECEIVE_REQUEST) {
+		if (from_nodeid == dir_nodeid)
+			from_dir = 1;
+		else
+			from_other = 1;
+	} else if (flags & R_REQUEST) {
+		from_local = 1;
+	}
+
+	/*
+	 * flags & R_RECEIVE_RECOVER is from dlm_recover_master_copy, so
+	 * from_nodeid has sent us a lock in dlm_recover_locks, believing
+	 * we're the new master.  Our local recovery may not have set
+	 * res_master_nodeid to our_nodeid yet, so allow either.  Don't
+	 * create the rsb; dlm_recover_process_copy() will handle EBADR
+	 * by resending.
+	 *
+	 * If someone sends us a request, we are the dir node, and we do
+	 * not find the rsb anywhere, then recreate it.  This happens if
+	 * someone sends us a request after we have removed/freed an rsb
+	 * from our toss list.  (They sent a request instead of lookup
+	 * because they are using an rsb from their toss list.)
+	 */
+
+	if (from_local || from_dir ||
+	    (from_other && (dir_nodeid == our_nodeid))) {
+		create = 1;
 	}
-	if (error == -ENOTBLK)
-		goto out;
 
-	error = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].toss, name, len, flags, &r);
+ retry:
+	if (create) {
+		error = pre_rsb_struct(ls);
+		if (error < 0)
+			goto out;
+	}
+
+	spin_lock(&ls->ls_rsbtbl[b].lock);
+
+	error = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].keep, name, len, &r);
 	if (error)
-		goto out;
+		goto do_toss;
+	
+	/*
+	 * rsb is active, so we can't check master_nodeid without lock_rsb.
+	 */
 
-	rb_erase(&r->res_hashnode, &ls->ls_rsbtbl[b].toss);
-	error = rsb_insert(r, &ls->ls_rsbtbl[b].keep);
+	kref_get(&r->res_ref);
+	error = 0;
+	goto out_unlock;
+
+
+ do_toss:
+	error = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].toss, name, len, &r);
 	if (error)
-		return error;
+		goto do_new;
 
-	if (dlm_no_directory(ls))
-		goto out;
+	/*
+	 * rsb found inactive (master_nodeid may be out of date unless
+	 * we are the dir_nodeid or were the master)  No other thread
+	 * is using this rsb because it's on the toss list, so we can
+	 * look at or update res_master_nodeid without lock_rsb.
+	 */
 
-	if (r->res_nodeid == -1) {
+	if ((r->res_master_nodeid != our_nodeid) && from_other) {
+		/* our rsb was not master, and another node (not the dir node)
+		   has sent us a request */
+		log_debug(ls, "find_rsb toss from_other %d master %d dir %d %s",
+			  from_nodeid, r->res_master_nodeid, dir_nodeid,
+			  r->res_name);
+		error = -ENOTBLK;
+		goto out_unlock;
+	}
+
+	if ((r->res_master_nodeid != our_nodeid) && from_dir) {
+		/* don't think this should ever happen */
+		log_error(ls, "find_rsb toss from_dir %d master %d",
+			  from_nodeid, r->res_master_nodeid);
+		dlm_print_rsb(r);
+		/* fix it and go on */
+		r->res_master_nodeid = our_nodeid;
+		r->res_nodeid = 0;
 		rsb_clear_flag(r, RSB_MASTER_UNCERTAIN);
 		r->res_first_lkid = 0;
-	} else if (r->res_nodeid > 0) {
+	}
+
+	if (from_local && (r->res_master_nodeid != our_nodeid)) {
+		/* Because we have held no locks on this rsb,
+		   res_master_nodeid could have become stale. */
 		rsb_set_flag(r, RSB_MASTER_UNCERTAIN);
 		r->res_first_lkid = 0;
+	}
+
+	rb_erase(&r->res_hashnode, &ls->ls_rsbtbl[b].toss);
+	error = rsb_insert(r, &ls->ls_rsbtbl[b].keep);
+	goto out_unlock;
+
+
+ do_new:
+	/*
+	 * rsb not found
+	 */
+
+	if (error == -EBADR && !create)
+		goto out_unlock;
+
+	error = get_rsb_struct(ls, name, len, &r);
+	if (error == -EAGAIN) {
+		spin_unlock(&ls->ls_rsbtbl[b].lock);
+		goto retry;
+	}
+	if (error)
+		goto out_unlock;
+
+	r->res_hash = hash;
+	r->res_bucket = b;
+	r->res_dir_nodeid = dir_nodeid;
+	kref_init(&r->res_ref);
+
+	if (from_dir) {
+		/* want to see how often this happens */
+		log_debug(ls, "find_rsb new from_dir %d recreate %s",
+			  from_nodeid, r->res_name);
+		r->res_master_nodeid = our_nodeid;
+		r->res_nodeid = 0;
+		goto out_add;
+	}
+
+	if (from_other && (dir_nodeid != our_nodeid)) {
+		/* should never happen */
+		log_error(ls, "find_rsb new from_other %d dir %d our %d %s",
+			  from_nodeid, dir_nodeid, our_nodeid, r->res_name);
+		dlm_free_rsb(r);
+		error = -ENOTBLK;
+		goto out_unlock;
+	}
+
+	if (from_other) {
+		log_debug(ls, "find_rsb new from_other %d dir %d %s",
+			  from_nodeid, dir_nodeid, r->res_name);
+	}
+
+	if (dir_nodeid == our_nodeid) {
+		/* When we are the dir nodeid, we can set the master
+		   node immediately */
+		r->res_master_nodeid = our_nodeid;
+		r->res_nodeid = 0;
 	} else {
-		DLM_ASSERT(r->res_nodeid == 0, dlm_print_rsb(r););
-		DLM_ASSERT(!rsb_flag(r, RSB_MASTER_UNCERTAIN),);
+		/* set_master will send_lookup to dir_nodeid */
+		r->res_master_nodeid = 0;
+		r->res_nodeid = -1;
 	}
+
+ out_add:
+	error = rsb_insert(r, &ls->ls_rsbtbl[b].keep);
+ out_unlock:
+	spin_unlock(&ls->ls_rsbtbl[b].lock);
  out:
 	*r_ret = r;
 	return error;
 }
 
+/* During recovery, other nodes can send us new MSTCPY locks (from
+   dlm_recover_locks) before we've made ourself master (in
+   dlm_recover_masters). */
+
+static int find_rsb_nodir(struct dlm_ls *ls, char *name, int len,
+			  uint32_t hash, uint32_t b,
+			  int dir_nodeid, int from_nodeid,
+			  unsigned int flags, struct dlm_rsb **r_ret)
+{
+	struct dlm_rsb *r = NULL;
+	int our_nodeid = dlm_our_nodeid();
+	int recover = (flags & R_RECEIVE_RECOVER);
+	int error;
+
+ retry:
+	error = pre_rsb_struct(ls);
+	if (error < 0)
+		goto out;
+
+	spin_lock(&ls->ls_rsbtbl[b].lock);
+
+	error = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].keep, name, len, &r);
+	if (error)
+		goto do_toss;
+
+	/*
+	 * rsb is active, so we can't check master_nodeid without lock_rsb.
+	 */
+
+	kref_get(&r->res_ref);
+	goto out_unlock;
+
+
+ do_toss:
+	error = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].toss, name, len, &r);
+	if (error)
+		goto do_new;
+
+	/*
+	 * rsb found inactive. No other thread is using this rsb because
+	 * it's on the toss list, so we can look at or update
+	 * res_master_nodeid without lock_rsb.
+	 */
+
+	if (!recover && (r->res_master_nodeid != our_nodeid) && from_nodeid) {
+		/* our rsb is not master, and another node has sent us a
+		   request; this should never happen */
+		log_error(ls, "find_rsb toss from_nodeid %d master %d dir %d",
+			  from_nodeid, r->res_master_nodeid, dir_nodeid);
+		dlm_print_rsb(r);
+		error = -ENOTBLK;
+		goto out_unlock;
+	}
+
+	if (!recover && (r->res_master_nodeid != our_nodeid) &&
+	    (dir_nodeid == our_nodeid)) {
+		/* our rsb is not master, and we are dir; may as well fix it;
+		   this should never happen */
+		log_error(ls, "find_rsb toss our %d master %d dir %d",
+			  our_nodeid, r->res_master_nodeid, dir_nodeid);
+		dlm_print_rsb(r);
+		r->res_master_nodeid = our_nodeid;
+		r->res_nodeid = 0;
+	}
+
+	rb_erase(&r->res_hashnode, &ls->ls_rsbtbl[b].toss);
+	error = rsb_insert(r, &ls->ls_rsbtbl[b].keep);
+	goto out_unlock;
+
+
+ do_new:
+	/*
+	 * rsb not found
+	 */
+
+	error = get_rsb_struct(ls, name, len, &r);
+	if (error == -EAGAIN) {
+		spin_unlock(&ls->ls_rsbtbl[b].lock);
+		goto retry;
+	}
+	if (error)
+		goto out_unlock;
+
+	r->res_hash = hash;
+	r->res_bucket = b;
+	r->res_dir_nodeid = dir_nodeid;
+	r->res_master_nodeid = dir_nodeid;
+	r->res_nodeid = (dir_nodeid == our_nodeid) ? 0 : dir_nodeid;
+	kref_init(&r->res_ref);
+
+	error = rsb_insert(r, &ls->ls_rsbtbl[b].keep);
+ out_unlock:
+	spin_unlock(&ls->ls_rsbtbl[b].lock);
+ out:
+	*r_ret = r;
+	return error;
+}
+
+static int find_rsb(struct dlm_ls *ls, char *name, int len, int from_nodeid,
+		    unsigned int flags, struct dlm_rsb **r_ret)
+{
+	uint32_t hash, b;
+	int dir_nodeid;
+
+	if (len > DLM_RESNAME_MAXLEN)
+		return -EINVAL;
+
+	hash = jhash(name, len, 0);
+	b = hash & (ls->ls_rsbtbl_size - 1);
+
+	dir_nodeid = dlm_hash2nodeid(ls, hash);
+
+	if (dlm_no_directory(ls))
+		return find_rsb_nodir(ls, name, len, hash, b, dir_nodeid,
+				      from_nodeid, flags, r_ret);
+	else
+		return find_rsb_dir(ls, name, len, hash, b, dir_nodeid,
+				      from_nodeid, flags, r_ret);
+}
+
+/* we have received a request and found that res_master_nodeid != our_nodeid,
+   so we need to return an error or make ourself the master */
+
+static int validate_master_nodeid(struct dlm_ls *ls, struct dlm_rsb *r,
+				  int from_nodeid)
+{
+	if (dlm_no_directory(ls)) {
+		log_error(ls, "find_rsb keep from_nodeid %d master %d dir %d",
+			  from_nodeid, r->res_master_nodeid,
+			  r->res_dir_nodeid);
+		dlm_print_rsb(r);
+		return -ENOTBLK;
+	}
+
+	if (from_nodeid != r->res_dir_nodeid) {
+		/* our rsb is not master, and another node (not the dir node)
+	   	   has sent us a request.  this is much more common when our
+	   	   master_nodeid is zero, so limit debug to non-zero.  */
+
+		if (r->res_master_nodeid) {
+			log_debug(ls, "validate master from_other %d master %d "
+				  "dir %d first %x %s", from_nodeid,
+				  r->res_master_nodeid, r->res_dir_nodeid,
+				  r->res_first_lkid, r->res_name);
+		}
+		return -ENOTBLK;
+	} else {
+		/* our rsb is not master, but the dir nodeid has sent us a
+	   	   request; this could happen with master 0 / res_nodeid -1 */
+
+		if (r->res_master_nodeid) {
+			log_error(ls, "validate master from_dir %d master %d "
+				  "first %x %s",
+				  from_nodeid, r->res_master_nodeid,
+				  r->res_first_lkid, r->res_name);
+		}
+
+		r->res_master_nodeid = dlm_our_nodeid();
+		r->res_nodeid = 0;
+		return 0;
+	}
+}
+
 /*
- * Find rsb in rsbtbl and potentially create/add one
+ * We're the dir node for this res and another node wants to know the
+ * master nodeid.  During normal operation (non recovery) this is only
+ * called from receive_lookup(); master lookups when the local node is
+ * the dir node are done by find_rsb().
  *
- * Delaying the release of rsb's has a similar benefit to applications keeping
- * NL locks on an rsb, but without the guarantee that the cached master value
- * will still be valid when the rsb is reused.  Apps aren't always smart enough
- * to keep NL locks on an rsb that they may lock again shortly; this can lead
- * to excessive master lookups and removals if we don't delay the release.
+ * normal operation, we are the dir node for a resource
+ * . _request_lock
+ * . set_master
+ * . send_lookup
+ * . receive_lookup
+ * . dlm_master_lookup flags 0
  *
- * Searching for an rsb means looking through both the normal list and toss
- * list.  When found on the toss list the rsb is moved to the normal list with
- * ref count of 1; when found on normal list the ref count is incremented.
+ * recover directory, we are rebuilding dir for all resources
+ * . dlm_recover_directory
+ * . dlm_rcom_names
+ *   remote node sends back the rsb names it is master of and we are dir of
+ * . dlm_master_lookup RECOVER_DIR (fix_master 0, from_master 1)
+ *   we either create new rsb setting remote node as master, or find existing
+ *   rsb and set master to be the remote node.
+ *
+ * recover masters, we are finding the new master for resources
+ * . dlm_recover_masters
+ * . recover_master
+ * . dlm_send_rcom_lookup
+ * . receive_rcom_lookup
+ * . dlm_master_lookup RECOVER_MASTER (fix_master 1, from_master 0)
  */
 
-static int find_rsb(struct dlm_ls *ls, char *name, int namelen,
-		    unsigned int flags, struct dlm_rsb **r_ret)
+int dlm_master_lookup(struct dlm_ls *ls, int from_nodeid, char *name, int len,
+		      unsigned int flags, int *r_nodeid, int *result)
 {
 	struct dlm_rsb *r = NULL;
-	uint32_t hash, bucket;
-	int error;
+	uint32_t hash, b;
+	int from_master = (flags & DLM_LU_RECOVER_DIR);
+	int fix_master = (flags & DLM_LU_RECOVER_MASTER);
+	int our_nodeid = dlm_our_nodeid();
+	int dir_nodeid, error, toss_list = 0;
 
-	if (namelen > DLM_RESNAME_MAXLEN) {
-		error = -EINVAL;
-		goto out;
+	if (len > DLM_RESNAME_MAXLEN)
+		return -EINVAL;
+
+	if (from_nodeid == our_nodeid) {
+		log_error(ls, "dlm_master_lookup from our_nodeid %d flags %x",
+			  our_nodeid, flags);
+		return -EINVAL;
 	}
 
-	if (dlm_no_directory(ls))
-		flags |= R_CREATE;
+	hash = jhash(name, len, 0);
+	b = hash & (ls->ls_rsbtbl_size - 1);
 
-	hash = jhash(name, namelen, 0);
-	bucket = hash & (ls->ls_rsbtbl_size - 1);
+	dir_nodeid = dlm_hash2nodeid(ls, hash);
+	if (dir_nodeid != our_nodeid) {
+		log_error(ls, "dlm_master_lookup from %d dir %d our %d h %x %d",
+			  from_nodeid, dir_nodeid, our_nodeid, hash,
+			  ls->ls_num_nodes);
+		*r_nodeid = -1;
+		return -EINVAL;
+	}
 
  retry:
-	if (flags & R_CREATE) {
-		error = pre_rsb_struct(ls);
-		if (error < 0)
-			goto out;
+	error = pre_rsb_struct(ls);
+	if (error < 0)
+		return error;
+
+	spin_lock(&ls->ls_rsbtbl[b].lock);
+	error = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].keep, name, len, &r);
+	if (!error) {
+		/* because the rsb is active, we need to lock_rsb before
+		   checking/changing re_master_nodeid */
+
+		hold_rsb(r);
+		spin_unlock(&ls->ls_rsbtbl[b].lock);
+		lock_rsb(r);
+		goto found;
 	}
 
-	spin_lock(&ls->ls_rsbtbl[bucket].lock);
+	error = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].toss, name, len, &r);
+	if (error)
+		goto not_found;
 
-	error = _search_rsb(ls, name, namelen, bucket, flags, &r);
-	if (!error)
-		goto out_unlock;
+	/* because the rsb is inactive (on toss list), it's not refcounted
+	   and lock_rsb is not used, but is protected by the rsbtbl lock */
 
-	if (error == -EBADR && !(flags & R_CREATE))
-		goto out_unlock;
+	toss_list = 1;
+ found:
+	if (r->res_dir_nodeid != our_nodeid) {
+		/* should not happen, but may as well fix it and carry on */
+		log_error(ls, "dlm_master_lookup res_dir %d our %d %s",
+			  r->res_dir_nodeid, our_nodeid, r->res_name);
+		r->res_dir_nodeid = our_nodeid;
+	}
+
+	if (fix_master && dlm_is_removed(ls, r->res_master_nodeid)) {
+		/* Recovery uses this function to set a new master when
+		   the previous master failed.  Setting NEW_MASTER will
+		   force dlm_recover_masters to call recover_master on this
+		   rsb even though the res_nodeid is no longer removed. */
+
+		r->res_master_nodeid = from_nodeid;
+		r->res_nodeid = from_nodeid;
+		rsb_set_flag(r, RSB_NEW_MASTER);
+
+		if (toss_list) {
+			/* I don't think we should ever find it on toss list. */
+			log_error(ls, "dlm_master_lookup fix_master on toss");
+			dlm_dump_rsb(r);
+		}
+	}
 
-	/* the rsb was found but wasn't a master copy */
-	if (error == -ENOTBLK)
-		goto out_unlock;
+	if (from_master && (r->res_master_nodeid != from_nodeid)) {
+		/* this will happen if from_nodeid became master during
+		   a previous recovery cycle, and we aborted the previous
+		   cycle before recovering this master value */
 
-	error = get_rsb_struct(ls, name, namelen, &r);
+		log_limit(ls, "dlm_master_lookup from_master %d "
+			  "master_nodeid %d res_nodeid %d first %x %s",
+			  from_nodeid, r->res_master_nodeid, r->res_nodeid,
+			  r->res_first_lkid, r->res_name);
+
+		if (r->res_master_nodeid == our_nodeid) {
+			log_error(ls, "from_master %d our_master", from_nodeid);
+			dlm_dump_rsb(r);
+			dlm_send_rcom_lookup_dump(r, from_nodeid);
+			goto out_found;
+		}
+
+		r->res_master_nodeid = from_nodeid;
+		r->res_nodeid = from_nodeid;
+		rsb_set_flag(r, RSB_NEW_MASTER);
+	}
+
+	if (!r->res_master_nodeid) {
+		/* this will happen if recovery happens while we're looking
+		   up the master for this rsb */
+
+		log_debug(ls, "dlm_master_lookup master 0 to %d first %x %s",
+			  from_nodeid, r->res_first_lkid, r->res_name);
+		r->res_master_nodeid = from_nodeid;
+		r->res_nodeid = from_nodeid;
+	}
+
+	if (!from_master && !fix_master &&
+	    (r->res_master_nodeid == from_nodeid)) {
+		/* this can happen when the master sends remove, the dir node
+		   finds the rsb on the keep list and ignores the remove,
+		   and the former master sends a lookup */
+
+		log_limit(ls, "dlm_master_lookup from master %d flags %x "
+			  "first %x %s", from_nodeid, flags,
+			  r->res_first_lkid, r->res_name);
+	}
+
+ out_found:
+	*r_nodeid = r->res_master_nodeid;
+	if (result)
+		*result = DLM_LU_MATCH;
+
+	if (toss_list) {
+		r->res_toss_time = jiffies;
+		/* the rsb was inactive (on toss list) */
+		spin_unlock(&ls->ls_rsbtbl[b].lock);
+	} else {
+		/* the rsb was active */
+		unlock_rsb(r);
+		put_rsb(r);
+	}
+	return 0;
+
+ not_found:
+	error = get_rsb_struct(ls, name, len, &r);
 	if (error == -EAGAIN) {
-		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
+		spin_unlock(&ls->ls_rsbtbl[b].lock);
 		goto retry;
 	}
 	if (error)
 		goto out_unlock;
 
 	r->res_hash = hash;
-	r->res_bucket = bucket;
-	r->res_nodeid = -1;
+	r->res_bucket = b;
+	r->res_dir_nodeid = our_nodeid;
+	r->res_master_nodeid = from_nodeid;
+	r->res_nodeid = from_nodeid;
 	kref_init(&r->res_ref);
+	r->res_toss_time = jiffies;
 
-	/* With no directory, the master can be set immediately */
-	if (dlm_no_directory(ls)) {
-		int nodeid = dlm_dir_nodeid(r);
-		if (nodeid == dlm_our_nodeid())
-			nodeid = 0;
-		r->res_nodeid = nodeid;
+	error = rsb_insert(r, &ls->ls_rsbtbl[b].toss);
+	if (error) {
+		/* should never happen */
+		dlm_free_rsb(r);
+		spin_unlock(&ls->ls_rsbtbl[b].lock);
+		goto retry;
 	}
-	error = rsb_insert(r, &ls->ls_rsbtbl[bucket].keep);
+
+	if (result)
+		*result = DLM_LU_ADD;
+	*r_nodeid = from_nodeid;
+	error = 0;
  out_unlock:
-	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
- out:
-	*r_ret = r;
+	spin_unlock(&ls->ls_rsbtbl[b].lock);
 	return error;
 }
 
@@ -605,17 +1099,27 @@ static void dlm_dump_rsb_hash(struct dlm_ls *ls, uint32_t hash)
 	}
 }
 
-/* This is only called to add a reference when the code already holds
-   a valid reference to the rsb, so there's no need for locking. */
-
-static inline void hold_rsb(struct dlm_rsb *r)
+void dlm_dump_rsb_name(struct dlm_ls *ls, char *name, int len)
 {
-	kref_get(&r->res_ref);
-}
+	struct dlm_rsb *r = NULL;
+	uint32_t hash, b;
+	int error;
 
-void dlm_hold_rsb(struct dlm_rsb *r)
-{
-	hold_rsb(r);
+	hash = jhash(name, len, 0);
+	b = hash & (ls->ls_rsbtbl_size - 1);
+
+	spin_lock(&ls->ls_rsbtbl[b].lock);
+	error = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].keep, name, len, &r);
+	if (!error)
+		goto out_dump;
+
+	error = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].toss, name, len, &r);
+	if (error)
+		goto out;
+ out_dump:
+	dlm_dump_rsb(r);
+ out:
+	spin_unlock(&ls->ls_rsbtbl[b].lock);
 }
 
 static void toss_rsb(struct kref *kref)
@@ -634,24 +1138,6 @@ static void toss_rsb(struct kref *kref)
 	}
 }
 
-/* When all references to the rsb are gone it's transferred to
-   the tossed list for later disposal. */
-
-static void put_rsb(struct dlm_rsb *r)
-{
-	struct dlm_ls *ls = r->res_ls;
-	uint32_t bucket = r->res_bucket;
-
-	spin_lock(&ls->ls_rsbtbl[bucket].lock);
-	kref_put(&r->res_ref, toss_rsb);
-	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
-}
-
-void dlm_put_rsb(struct dlm_rsb *r)
-{
-	put_rsb(r);
-}
-
 /* See comment for unhold_lkb */
 
 static void unhold_rsb(struct dlm_rsb *r)
@@ -1138,27 +1624,13 @@ static int remove_from_waiters_ms(struct dlm_lkb *lkb, struct dlm_message *ms)
 	return error;
 }
 
-static void dir_remove(struct dlm_rsb *r)
-{
-	int to_nodeid;
-
-	if (dlm_no_directory(r->res_ls))
-		return;
-
-	to_nodeid = dlm_dir_nodeid(r);
-	if (to_nodeid != dlm_our_nodeid())
-		send_remove(r);
-	else
-		dlm_dir_remove_entry(r->res_ls, to_nodeid,
-				     r->res_name, r->res_length);
-}
-
 /* FIXME: make this more efficient */
 
 static int shrink_bucket(struct dlm_ls *ls, int b)
 {
 	struct rb_node *n;
 	struct dlm_rsb *r;
+	int our_nodeid = dlm_our_nodeid();
 	int count = 0, found;
 
 	for (;;) {
@@ -1166,6 +1638,17 @@ static int shrink_bucket(struct dlm_ls *ls, int b)
 		spin_lock(&ls->ls_rsbtbl[b].lock);
 		for (n = rb_first(&ls->ls_rsbtbl[b].toss); n; n = rb_next(n)) {
 			r = rb_entry(n, struct dlm_rsb, res_hashnode);
+
+			/* If we're the directory record for this rsb, and
+			   we're not the master of it, then we need to wait
+			   for the master node to send us a dir remove for
+			   before removing the dir record. */
+
+			if (!dlm_no_directory(ls) && !is_master(r) &&
+			    (dlm_dir_nodeid(r) == our_nodeid)) {
+				continue;
+			}
+
 			if (!time_after_eq(jiffies, r->res_toss_time +
 					   dlm_config.ci_toss_secs * HZ))
 				continue;
@@ -1182,8 +1665,15 @@ static int shrink_bucket(struct dlm_ls *ls, int b)
 			rb_erase(&r->res_hashnode, &ls->ls_rsbtbl[b].toss);
 			spin_unlock(&ls->ls_rsbtbl[b].lock);
 
-			if (is_master(r))
-				dir_remove(r);
+			/* We're the master of this rsb but we're not
+			   the directory record, so we need to tell the
+			   dir node to remove the dir record. */
+
+			if (!dlm_no_directory(ls) && is_master(r) &&
+			    (dlm_dir_nodeid(r) != our_nodeid)) {
+				send_remove(r);
+			}
+
 			dlm_free_rsb(r);
 			count++;
 		} else {
@@ -2078,8 +2568,7 @@ static void send_blocking_asts_all(struct dlm_rsb *r, struct dlm_lkb *lkb)
 
 static int set_master(struct dlm_rsb *r, struct dlm_lkb *lkb)
 {
-	struct dlm_ls *ls = r->res_ls;
-	int i, error, dir_nodeid, ret_nodeid, our_nodeid = dlm_our_nodeid();
+	int our_nodeid = dlm_our_nodeid();
 
 	if (rsb_flag(r, RSB_MASTER_UNCERTAIN)) {
 		rsb_clear_flag(r, RSB_MASTER_UNCERTAIN);
@@ -2093,53 +2582,35 @@ static int set_master(struct dlm_rsb *r, struct dlm_lkb *lkb)
 		return 1;
 	}
 
-	if (r->res_nodeid == 0) {
+	if (r->res_master_nodeid == our_nodeid) {
 		lkb->lkb_nodeid = 0;
 		return 0;
 	}
 
-	if (r->res_nodeid > 0) {
-		lkb->lkb_nodeid = r->res_nodeid;
+	if (r->res_master_nodeid) {
+		lkb->lkb_nodeid = r->res_master_nodeid;
 		return 0;
 	}
 
-	DLM_ASSERT(r->res_nodeid == -1, dlm_dump_rsb(r););
-
-	dir_nodeid = dlm_dir_nodeid(r);
-
-	if (dir_nodeid != our_nodeid) {
-		r->res_first_lkid = lkb->lkb_id;
-		send_lookup(r, lkb);
-		return 1;
-	}
-
-	for (i = 0; i < 2; i++) {
-		/* It's possible for dlm_scand to remove an old rsb for
-		   this same resource from the toss list, us to create
-		   a new one, look up the master locally, and find it
-		   already exists just before dlm_scand does the
-		   dir_remove() on the previous rsb. */
-
-		error = dlm_dir_lookup(ls, our_nodeid, r->res_name,
-				       r->res_length, &ret_nodeid);
-		if (!error)
-			break;
-		log_debug(ls, "dir_lookup error %d %s", error, r->res_name);
-		schedule();
-	}
-	if (error && error != -EEXIST)
-		return error;
-
-	if (ret_nodeid == our_nodeid) {
-		r->res_first_lkid = 0;
+	if (dlm_dir_nodeid(r) == our_nodeid) {
+		/* This is a somewhat unusual case; find_rsb will usually
+		   have set res_master_nodeid when dir nodeid is local, but
+		   there are cases where we become the dir node after we've
+		   past find_rsb and go through _request_lock again.
+		   confirm_master() or process_lookup_list() needs to be
+		   called after this. */
+		log_debug(r->res_ls, "set_master %x self master %d dir %d %s",
+			  lkb->lkb_id, r->res_master_nodeid, r->res_dir_nodeid,
+			  r->res_name);
+		r->res_master_nodeid = our_nodeid;
 		r->res_nodeid = 0;
 		lkb->lkb_nodeid = 0;
-	} else {
-		r->res_first_lkid = lkb->lkb_id;
-		r->res_nodeid = ret_nodeid;
-		lkb->lkb_nodeid = ret_nodeid;
+		return 0;
 	}
-	return 0;
+
+	r->res_first_lkid = lkb->lkb_id;
+	send_lookup(r, lkb);
+	return 1;
 }
 
 static void process_lookup_list(struct dlm_rsb *r)
@@ -2584,7 +3055,7 @@ static void do_unlock_effects(struct dlm_rsb *r, struct dlm_lkb *lkb,
 }
 
 /* returns: 0 did nothing, -DLM_ECANCEL canceled lock */
- 
+
 static int do_cancel(struct dlm_rsb *r, struct dlm_lkb *lkb)
 {
 	int error;
@@ -2708,11 +3179,11 @@ static int request_lock(struct dlm_ls *ls, struct dlm_lkb *lkb, char *name,
 
 	error = validate_lock_args(ls, lkb, args);
 	if (error)
-		goto out;
+		return error;
 
-	error = find_rsb(ls, name, len, R_CREATE, &r);
+	error = find_rsb(ls, name, len, 0, R_REQUEST, &r);
 	if (error)
-		goto out;
+		return error;
 
 	lock_rsb(r);
 
@@ -2723,8 +3194,6 @@ static int request_lock(struct dlm_ls *ls, struct dlm_lkb *lkb, char *name,
 
 	unlock_rsb(r);
 	put_rsb(r);
-
- out:
 	return error;
 }
 
@@ -3406,8 +3875,11 @@ static int receive_request(struct dlm_ls *ls, struct dlm_message *ms)
 {
 	struct dlm_lkb *lkb;
 	struct dlm_rsb *r;
+	int from_nodeid;
 	int error, namelen;
 
+	from_nodeid = ms->m_header.h_nodeid;
+
 	error = create_lkb(ls, &lkb);
 	if (error)
 		goto fail;
@@ -3420,9 +3892,16 @@ static int receive_request(struct dlm_ls *ls, struct dlm_message *ms)
 		goto fail;
 	}
 
+	/* The dir node is the authority on whether we are the master
+	   for this rsb or not, so if the master sends us a request, we should
+	   recreate the rsb if we've destroyed it.   This race happens when we
+	   send a remove message to the dir node at the same time that the dir
+	   node sends us a request for the rsb. */
+
 	namelen = receive_extralen(ms);
 
-	error = find_rsb(ls, ms->m_extra, namelen, R_MASTER, &r);
+	error = find_rsb(ls, ms->m_extra, namelen, from_nodeid,
+			 R_RECEIVE_REQUEST, &r);
 	if (error) {
 		__put_lkb(ls, lkb);
 		goto fail;
@@ -3430,6 +3909,16 @@ static int receive_request(struct dlm_ls *ls, struct dlm_message *ms)
 
 	lock_rsb(r);
 
+	if (r->res_master_nodeid != dlm_our_nodeid()) {
+		error = validate_master_nodeid(ls, r, from_nodeid);
+		if (error) {
+			unlock_rsb(r);
+			put_rsb(r);
+			__put_lkb(ls, lkb);
+			goto fail;
+		}
+	}
+
 	attach_lkb(r, lkb);
 	error = do_request(r, lkb);
 	send_request_reply(r, lkb, error);
@@ -3445,6 +3934,23 @@ static int receive_request(struct dlm_ls *ls, struct dlm_message *ms)
 	return 0;
 
  fail:
+	/* TODO: instead of returning ENOTBLK, add the lkb to res_lookup
+	   and do this receive_request again from process_lookup_list once
+	   we get the lookup reply.  This would avoid a many repeated
+	   ENOTBLK request failures when the lookup reply designating us
+	   as master is delayed. */
+
+	/* We could repeatedly return -EBADR here if our send_remove() is
+	   delayed in being sent/arriving/being processed on the dir node.
+	   Another node would repeatedly lookup up the master, and the dir
+	   node would continue returning our nodeid until our send_remove
+	   took effect. */
+
+	if (error != -ENOTBLK) {
+		log_limit(ls, "receive_request %x from %d %d",
+			  ms->m_lkid, from_nodeid, error);
+	}
+
 	setup_stub_lkb(ls, ms);
 	send_request_reply(&ls->ls_stub_rsb, &ls->ls_stub_lkb, error);
 	return error;
@@ -3651,49 +4157,110 @@ static int receive_bast(struct dlm_ls *ls, struct dlm_message *ms)
 
 static void receive_lookup(struct dlm_ls *ls, struct dlm_message *ms)
 {
-	int len, error, ret_nodeid, dir_nodeid, from_nodeid, our_nodeid;
+	int len, error, ret_nodeid, from_nodeid, our_nodeid;
 
 	from_nodeid = ms->m_header.h_nodeid;
 	our_nodeid = dlm_our_nodeid();
 
 	len = receive_extralen(ms);
 
-	dir_nodeid = dlm_hash2nodeid(ls, ms->m_hash);
-	if (dir_nodeid != our_nodeid) {
-		log_error(ls, "lookup dir_nodeid %d from %d",
-			  dir_nodeid, from_nodeid);
-		error = -EINVAL;
-		ret_nodeid = -1;
-		goto out;
-	}
-
-	error = dlm_dir_lookup(ls, from_nodeid, ms->m_extra, len, &ret_nodeid);
+	error = dlm_master_lookup(ls, from_nodeid, ms->m_extra, len, 0,
+				  &ret_nodeid, NULL);
 
 	/* Optimization: we're master so treat lookup as a request */
 	if (!error && ret_nodeid == our_nodeid) {
 		receive_request(ls, ms);
 		return;
 	}
- out:
 	send_lookup_reply(ls, ms, ret_nodeid, error);
 }
 
 static void receive_remove(struct dlm_ls *ls, struct dlm_message *ms)
 {
-	int len, dir_nodeid, from_nodeid;
+	char name[DLM_RESNAME_MAXLEN+1];
+	struct dlm_rsb *r;
+	uint32_t hash, b;
+	int rv, len, dir_nodeid, from_nodeid;
 
 	from_nodeid = ms->m_header.h_nodeid;
 
 	len = receive_extralen(ms);
 
+	if (len > DLM_RESNAME_MAXLEN) {
+		log_error(ls, "receive_remove from %d bad len %d",
+			  from_nodeid, len);
+		return;
+	}
+
 	dir_nodeid = dlm_hash2nodeid(ls, ms->m_hash);
 	if (dir_nodeid != dlm_our_nodeid()) {
-		log_error(ls, "remove dir entry dir_nodeid %d from %d",
-			  dir_nodeid, from_nodeid);
+		log_error(ls, "receive_remove from %d bad nodeid %d",
+			  from_nodeid, dir_nodeid);
 		return;
 	}
 
-	dlm_dir_remove_entry(ls, from_nodeid, ms->m_extra, len);
+	/* Look for name on rsbtbl.toss, if it's there, kill it.
+	   If it's on rsbtbl.keep, it's being used, and we should ignore this
+	   message.  This is an expected race between the dir node sending a
+	   request to the master node at the same time as the master node sends
+	   a remove to the dir node.  The resolution to that race is for the
+	   dir node to ignore the remove message, and the master node to
+	   recreate the master rsb when it gets a request from the dir node for
+	   an rsb it doesn't have. */
+
+	memset(name, 0, sizeof(name));
+	memcpy(name, ms->m_extra, len);
+
+	hash = jhash(name, len, 0);
+	b = hash & (ls->ls_rsbtbl_size - 1);
+
+	spin_lock(&ls->