dlm: fixes for nodir mode

The "nodir" mode (statically assign master nodes instead
of using the resource directory) has always been highly
experimental, and never seriously used.  This commit
fixes a number of problems, making nodir much more usable.

- Major change to recovery: recover all locks and restart
  all in-progress operations after recovery.  In some
  cases it's not possible to know which in-progess locks
  to recover, so recover all.  (Most require recovery
  in nodir mode anyway since rehashing changes most
  master nodes.)

- Change the way nodir mode is enabled, from a command
  line mount arg passed through gfs2, into a sysfs
  file managed by dlm_controld, consistent with the
  other config settings.

- Allow recovering MSTCPY locks on an rsb that has not
  yet been turned into a master copy.

- Ignore RCOM_LOCK and RCOM_LOCK_REPLY recovery messages
  from a previous, aborted recovery cycle.  Base this
  on the local recovery status not being in the state
  where any nodes should be sending LOCK messages for the
  current recovery cycle.

- Hold rsb lock around dlm_purge_mstcpy_locks() because it
  may run concurrently with dlm_recover_master_copy().

- Maintain highbast on process-copy lkb's (in addition to
  the master as is usual), because the lkb can switch
  back and forth between being a master and being a
  process copy as the master node changes in recovery.

- When recovering MSTCPY locks, flag rsb's that have
  non-empty convert or waiting queues for granting
  at the end of recovery.  (Rename flag from LOCKS_PURGED
  to RECOVER_GRANT and similar for the recovery function,
  because it's not only resources with purged locks
  that need grant a grant attempt.)

- Replace a couple of unnecessary assertion panics with
  error messages.

Signed-off-by: David Teigland <teigland@redhat.com>

9 files changed, 303 insertions, 162 deletions

diff --git a/fs/dlm/ast.c b/fs/dlm/ast.c
index 90e5997262ea..63dc19c54d5a 100644
--- a/fs/dlm/ast.c
+++ b/fs/dlm/ast.c
@@ -310,6 +310,7 @@ void dlm_callback_resume(struct dlm_ls *ls)
 	}
 	mutex_unlock(&ls->ls_cb_mutex);
 
-	log_debug(ls, "dlm_callback_resume %d", count);
+	if (count)
+		log_debug(ls, "dlm_callback_resume %d", count);
 }
 
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index 0e74832c021b..bc342f7ac3af 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -271,6 +271,8 @@ struct dlm_lkb {
 	ktime_t			lkb_last_cast_time;	/* for debugging */
 	ktime_t			lkb_last_bast_time;	/* for debugging */
 
+	uint64_t		lkb_recover_seq; /* from ls_recover_seq */
+
 	char			*lkb_lvbptr;
 	struct dlm_lksb		*lkb_lksb;      /* caller's status block */
 	void			(*lkb_astfn) (void *astparam);
@@ -325,7 +327,7 @@ enum rsb_flags {
 	RSB_NEW_MASTER,
 	RSB_NEW_MASTER2,
 	RSB_RECOVER_CONVERT,
-	RSB_LOCKS_PURGED,
+	RSB_RECOVER_GRANT,
 };
 
 static inline void rsb_set_flag(struct dlm_rsb *r, enum rsb_flags flag)
@@ -571,6 +573,7 @@ struct dlm_ls {
 	struct mutex		ls_requestqueue_mutex;
 	struct dlm_rcom		*ls_recover_buf;
 	int			ls_recover_nodeid; /* for debugging */
+	unsigned int		ls_recover_locks_in; /* for log info */
 	uint64_t		ls_rcom_seq;
 	spinlock_t		ls_rcom_spin;
 	struct list_head	ls_recover_list;
@@ -597,6 +600,7 @@ struct dlm_ls {
 #define LSFL_UEVENT_WAIT	5
 #define LSFL_TIMEWARN		6
 #define LSFL_CB_DELAY		7
+#define LSFL_NODIR		8
 
 /* much of this is just saving user space pointers associated with the
    lock that we pass back to the user lib with an ast */
@@ -644,7 +648,7 @@ static inline int dlm_recovery_stopped(struct dlm_ls *ls)
 
 static inline int dlm_no_directory(struct dlm_ls *ls)
 {
-	return (ls->ls_exflags & DLM_LSFL_NODIR) ? 1 : 0;
+	return test_bit(LSFL_NODIR, &ls->ls_flags);
 }
 
 int dlm_netlink_init(void);
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index f3ba70301a45..bdafb65a5234 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -161,10 +161,11 @@ static const int __quecvt_compat_matrix[8][8] = {
 void dlm_print_lkb(struct dlm_lkb *lkb)
 {
 	printk(KERN_ERR "lkb: nodeid %d id %x remid %x exflags %x flags %x "
-	       "sts %d rq %d gr %d wait_type %d wait_nodeid %d\n",
+	       "sts %d rq %d gr %d wait_type %d wait_nodeid %d seq %llu\n",
 	       lkb->lkb_nodeid, lkb->lkb_id, lkb->lkb_remid, lkb->lkb_exflags,
 	       lkb->lkb_flags, lkb->lkb_status, lkb->lkb_rqmode,
-	       lkb->lkb_grmode, lkb->lkb_wait_type, lkb->lkb_wait_nodeid);
+	       lkb->lkb_grmode, lkb->lkb_wait_type, lkb->lkb_wait_nodeid,
+	       (unsigned long long)lkb->lkb_recover_seq);
 }
 
 static void dlm_print_rsb(struct dlm_rsb *r)
@@ -251,8 +252,6 @@ static inline int is_process_copy(struct dlm_lkb *lkb)
 
 static inline int is_master_copy(struct dlm_lkb *lkb)
 {
-	if (lkb->lkb_flags & DLM_IFL_MSTCPY)
-		DLM_ASSERT(lkb->lkb_nodeid, dlm_print_lkb(lkb););
 	return (lkb->lkb_flags & DLM_IFL_MSTCPY) ? 1 : 0;
 }
 
@@ -1519,13 +1518,13 @@ static void _grant_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
 	}
 
 	lkb->lkb_rqmode = DLM_LOCK_IV;
+	lkb->lkb_highbast = 0;
 }
 
 static void grant_lock(struct dlm_rsb *r, struct dlm_lkb *lkb)
 {
 	set_lvb_lock(r, lkb);
 	_grant_lock(r, lkb);
-	lkb->lkb_highbast = 0;
 }
 
 static void grant_lock_pc(struct dlm_rsb *r, struct dlm_lkb *lkb,
@@ -1887,7 +1886,8 @@ static int can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now,
 /* Returns the highest requested mode of all blocked conversions; sets
    cw if there's a blocked conversion to DLM_LOCK_CW. */
 
-static int grant_pending_convert(struct dlm_rsb *r, int high, int *cw)
+static int grant_pending_convert(struct dlm_rsb *r, int high, int *cw,
+				 unsigned int *count)
 {
 	struct dlm_lkb *lkb, *s;
 	int hi, demoted, quit, grant_restart, demote_restart;
@@ -1906,6 +1906,8 @@ static int grant_pending_convert(struct dlm_rsb *r, int high, int *cw)
 		if (can_be_granted(r, lkb, 0, &deadlk)) {
 			grant_lock_pending(r, lkb);
 			grant_restart = 1;
+			if (count)
+				(*count)++;
 			continue;
 		}
 
@@ -1939,14 +1941,17 @@ static int grant_pending_convert(struct dlm_rsb *r, int high, int *cw)
 	return max_t(int, high, hi);
 }
 
-static int grant_pending_wait(struct dlm_rsb *r, int high, int *cw)
+static int grant_pending_wait(struct dlm_rsb *r, int high, int *cw,
+			      unsigned int *count)
 {
 	struct dlm_lkb *lkb, *s;
 
 	list_for_each_entry_safe(lkb, s, &r->res_waitqueue, lkb_statequeue) {
-		if (can_be_granted(r, lkb, 0, NULL))
+		if (can_be_granted(r, lkb, 0, NULL)) {
 			grant_lock_pending(r, lkb);
-                else {
+			if (count)
+				(*count)++;
+		} else {
 			high = max_t(int, lkb->lkb_rqmode, high);
 			if (lkb->lkb_rqmode == DLM_LOCK_CW)
 				*cw = 1;
@@ -1975,16 +1980,20 @@ static int lock_requires_bast(struct dlm_lkb *gr, int high, int cw)
 	return 0;
 }
 
-static void grant_pending_locks(struct dlm_rsb *r)
+static void grant_pending_locks(struct dlm_rsb *r, unsigned int *count)
 {
 	struct dlm_lkb *lkb, *s;
 	int high = DLM_LOCK_IV;
 	int cw = 0;
 
-	DLM_ASSERT(is_master(r), dlm_dump_rsb(r););
+	if (!is_master(r)) {
+		log_print("grant_pending_locks r nodeid %d", r->res_nodeid);
+		dlm_dump_rsb(r);
+		return;
+	}
 
-	high = grant_pending_convert(r, high, &cw);
-	high = grant_pending_wait(r, high, &cw);
+	high = grant_pending_convert(r, high, &cw, count);
+	high = grant_pending_wait(r, high, &cw, count);
 
 	if (high == DLM_LOCK_IV)
 		return;
@@ -2520,7 +2529,7 @@ static int do_convert(struct dlm_rsb *r, struct dlm_lkb *lkb)
 	   before we try again to grant this one. */
 
 	if (is_demoted(lkb)) {
-		grant_pending_convert(r, DLM_LOCK_IV, NULL);
+		grant_pending_convert(r, DLM_LOCK_IV, NULL, NULL);
 		if (_can_be_granted(r, lkb, 1)) {
 			grant_lock(r, lkb);
 			queue_cast(r, lkb, 0);
@@ -2548,7 +2557,7 @@ static void do_convert_effects(struct dlm_rsb *r, struct dlm_lkb *lkb,
 {
 	switch (error) {
 	case 0:
-		grant_pending_locks(r);
+		grant_pending_locks(r, NULL);
 		/* grant_pending_locks also sends basts */
 		break;
 	case -EAGAIN:
@@ -2571,7 +2580,7 @@ static int do_unlock(struct dlm_rsb *r, struct dlm_lkb *lkb)
 static void do_unlock_effects(struct dlm_rsb *r, struct dlm_lkb *lkb,
 			      int error)
 {
-	grant_pending_locks(r);
+	grant_pending_locks(r, NULL);
 }
 
 /* returns: 0 did nothing, -DLM_ECANCEL canceled lock */
@@ -2592,7 +2601,7 @@ static void do_cancel_effects(struct dlm_rsb *r, struct dlm_lkb *lkb,
 			      int error)
 {
 	if (error)
-		grant_pending_locks(r);
+		grant_pending_locks(r, NULL);
 }
 
 /*
@@ -3452,8 +3461,9 @@ static int receive_convert(struct dlm_ls *ls, struct dlm_message *ms)
 		goto fail;
 
 	if (lkb->lkb_remid != ms->m_lkid) {
-		log_error(ls, "receive_convert %x remid %x remote %d %x",
-			  lkb->lkb_id, lkb->lkb_remid,
+		log_error(ls, "receive_convert %x remid %x recover_seq %llu "
+			  "remote %d %x", lkb->lkb_id, lkb->lkb_remid,
+			  (unsigned long long)lkb->lkb_recover_seq,
 			  ms->m_header.h_nodeid, ms->m_lkid);
 		error = -ENOENT;
 		goto fail;
@@ -3631,6 +3641,7 @@ static int receive_bast(struct dlm_ls *ls, struct dlm_message *ms)
 		goto out;
 
 	queue_bast(r, lkb, ms->m_bastmode);
+	lkb->lkb_highbast = ms->m_bastmode;
  out:
 	unlock_rsb(r);
 	put_rsb(r);
@@ -3710,8 +3721,13 @@ static int receive_request_reply(struct dlm_ls *ls, struct dlm_message *ms)
 
 	mstype = lkb->lkb_wait_type;
 	error = remove_from_waiters(lkb, DLM_MSG_REQUEST_REPLY);
-	if (error)
+	if (error) {
+		log_error(ls, "receive_request_reply %x remote %d %x result %d",
+			  lkb->lkb_id, ms->m_header.h_nodeid, ms->m_lkid,
+			  ms->m_result);
+		dlm_dump_rsb(r);
 		goto out;
+	}
 
 	/* Optimization: the dir node was also the master, so it took our
 	   lookup as a request and sent request reply instead of lookup reply */
@@ -4122,21 +4138,28 @@ static void _receive_message(struct dlm_ls *ls, struct dlm_message *ms,
 	 * happen in normal usage for the async messages and cancel, so
 	 * only use log_debug for them.
 	 *
-	 * Other errors are expected and normal.
+	 * Some errors are expected and normal.
 	 */
 
 	if (error == -ENOENT && noent) {
-		log_debug(ls, "receive %d no %x remote %d %x seq %u",
+		log_debug(ls, "receive %d no %x remote %d %x saved_seq %u",
 			  ms->m_type, ms->m_remid, ms->m_header.h_nodeid,
 			  ms->m_lkid, saved_seq);
 	} else if (error == -ENOENT) {
-		log_error(ls, "receive %d no %x remote %d %x seq %u",
+		log_error(ls, "receive %d no %x remote %d %x saved_seq %u",
 			  ms->m_type, ms->m_remid, ms->m_header.h_nodeid,
 			  ms->m_lkid, saved_seq);
 
 		if (ms->m_type == DLM_MSG_CONVERT)
 			dlm_dump_rsb_hash(ls, ms->m_hash);
 	}
+
+	if (error == -EINVAL) {
+		log_error(ls, "receive %d inval from %d lkid %x remid %x "
+			  "saved_seq %u",
+			  ms->m_type, ms->m_header.h_nodeid,
+			  ms->m_lkid, ms->m_remid, saved_seq);
+	}
 }
 
 /* If the lockspace is in recovery mode (locking stopped), then normal
@@ -4200,9 +4223,11 @@ void dlm_receive_buffer(union dlm_packet *p, int nodeid)
 
 	ls = dlm_find_lockspace_global(hd->h_lockspace);
 	if (!ls) {
-		if (dlm_config.ci_log_debug)
-			log_print("invalid lockspace %x from %d cmd %d type %d",
-				  hd->h_lockspace, nodeid, hd->h_cmd, type);
+		if (dlm_config.ci_log_debug) {
+			printk_ratelimited(KERN_DEBUG "dlm: invalid lockspace "
+				"%u from %d cmd %d type %d\n",
+				hd->h_lockspace, nodeid, hd->h_cmd, type);
+		}
 
 		if (hd->h_cmd == DLM_RCOM && type == DLM_RCOM_STATUS)
 			dlm_send_ls_not_ready(nodeid, &p->rcom);
@@ -4253,16 +4278,10 @@ static void recover_convert_waiter(struct dlm_ls *ls, struct dlm_lkb *lkb,
 static int waiter_needs_recovery(struct dlm_ls *ls, struct dlm_lkb *lkb,
 				 int dir_nodeid)
 {
-	if (dlm_is_removed(ls, lkb->lkb_wait_nodeid))
-		return 1;
-
-	if (!dlm_no_directory(ls))
-		return 0;
-
-	if (dir_nodeid == dlm_our_nodeid())
+	if (dlm_no_directory(ls))
 		return 1;
 
-	if (dir_nodeid != lkb->lkb_wait_nodeid)
+	if (dlm_is_removed(ls, lkb->lkb_wait_nodeid))
 		return 1;
 
 	return 0;
@@ -4519,112 +4538,177 @@ int dlm_recover_waiters_post(struct dlm_ls *ls)
 	return error;
 }
 
-static void purge_queue(struct dlm_rsb *r, struct list_head *queue,
-			int (*test)(struct dlm_ls *ls, struct dlm_lkb *lkb))
+static void purge_mstcpy_list(struct dlm_ls *ls, struct dlm_rsb *r,
+			      struct list_head *list)
 {
-	struct dlm_ls *ls = r->res_ls;
 	struct dlm_lkb *lkb, *safe;
 
-	list_for_each_entry_safe(lkb, safe, queue, lkb_statequeue) {
-		if (test(ls, lkb)) {
-			rsb_set_flag(r, RSB_LOCKS_PURGED);
-			del_lkb(r, lkb);
-			/* this put should free the lkb */
-			if (!dlm_put_lkb(lkb))
-				log_error(ls, "purged lkb not released");
-		}
+	list_for_each_entry_safe(lkb, safe, list, lkb_statequeue) {
+		if (!is_master_copy(lkb))
+			continue;
+
+		/* don't purge lkbs we've added in recover_master_copy for
+		   the current recovery seq */
+
+		if (lkb->lkb_recover_seq == ls->ls_recover_seq)
+			continue;
+
+		del_lkb(r, lkb);
+
+		/* this put should free the lkb */
+		if (!dlm_put_lkb(lkb))
+			log_error(ls, "purged mstcpy lkb not released");
 	}
 }
 
-static int purge_dead_test(struct dlm_ls *ls, struct dlm_lkb *lkb)
+void dlm_purge_mstcpy_locks(struct dlm_rsb *r)
 {
-	return (is_master_copy(lkb) && dlm_is_removed(ls, lkb->lkb_nodeid));
-}
+	struct dlm_ls *ls = r->res_ls;
 
-static int purge_mstcpy_test(struct dlm_ls *ls, struct dlm_lkb *lkb)
-{
-	return is_master_copy(lkb);
+	purge_mstcpy_list(ls, r, &r->res_grantqueue);
+	purge_mstcpy_list(ls, r, &r->res_convertqueue);
+	purge_mstcpy_list(ls, r, &r->res_waitqueue);
 }
 
-static void purge_dead_locks(struct dlm_rsb *r)
+static void purge_dead_list(struct dlm_ls *ls, struct dlm_rsb *r,
+			    struct list_head *list,
+			    int nodeid_gone, unsigned int *count)
 {
-	purge_queue(r, &r->res_grantqueue, &purge_dead_test);
-	purge_queue(r, &r->res_convertqueue, &purge_dead_test);
-	purge_queue(r, &r->res_waitqueue, &purge_dead_test);
-}
+	struct dlm_lkb *lkb, *safe;
 
-void dlm_purge_mstcpy_locks(struct dlm_rsb *r)
-{
-	purge_queue(r, &r->res_grantqueue, &purge_mstcpy_test);
-	purge_queue(r, &r->res_convertqueue, &purge_mstcpy_test);
-	purge_queue(r, &r->res_waitqueue, &purge_mstcpy_test);
+	list_for_each_entry_safe(lkb, safe, list, lkb_statequeue) {
+		if (!is_master_copy(lkb))
+			continue;
+
+		if ((lkb->lkb_nodeid == nodeid_gone) ||
+		    dlm_is_removed(ls, lkb->lkb_nodeid)) {
+
+			del_lkb(r, lkb);
+
+			/* this put should free the lkb */
+			if (!dlm_put_lkb(lkb))
+				log_error(ls, "purged dead lkb not released");
+
+			rsb_set_flag(r, RSB_RECOVER_GRANT);
+
+			(*count)++;
+		}
+	}
 }
 
 /* Get rid of locks held by nodes that are gone. */
 
-int dlm_purge_locks(struct dlm_ls *ls)
+void dlm_recover_purge(struct dlm_ls *ls)
 {
 	struct dlm_rsb *r;
+	struct dlm_member *memb;
+	int nodes_count = 0;
+	int nodeid_gone = 0;
+	unsigned int lkb_count = 0;
+
+	/* cache one removed nodeid to optimize the common
+	   case of a single node removed */
+
+	list_for_each_entry(memb, &ls->ls_nodes_gone, list) {
+		nodes_count++;
+		nodeid_gone = memb->nodeid;
+	}
 
-	log_debug(ls, "dlm_purge_locks");
+	if (!nodes_count)
+		return;
 
 	down_write(&ls->ls_root_sem);
 	list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
 		hold_rsb(r);
 		lock_rsb(r);
-		if (is_master(r))
-			purge_dead_locks(r);
+		if (is_master(r)) {
+			purge_dead_list(ls, r, &r->res_grantqueue,
+					nodeid_gone, &lkb_count);
+			purge_dead_list(ls, r, &r->res_convertqueue,
+					nodeid_gone, &lkb_count);
+			purge_dead_list(ls, r, &r->res_waitqueue,
+					nodeid_gone, &lkb_count);
+		}
 		unlock_rsb(r);
 		unhold_rsb(r);
-
-		schedule();
+		cond_resched();
 	}
 	up_write(&ls->ls_root_sem);
 
-	return 0;
+	if (lkb_count)
+		log_debug(ls, "dlm_recover_purge %u locks for %u nodes",
+			  lkb_count, nodes_count);
 }
 
-static struct dlm_rsb *find_purged_rsb(struct dlm_ls *ls, int bucket)
+static struct dlm_rsb *find_grant_rsb(struct dlm_ls *ls, int bucket)
 {
 	struct rb_node *n;
-	struct dlm_rsb *r, *r_ret = NULL;
+	struct dlm_rsb *r;
 
 	spin_lock(&ls->ls_rsbtbl[bucket].lock);
 	for (n = rb_first(&ls->ls_rsbtbl[bucket].keep); n; n = rb_next(n)) {
 		r = rb_entry(n, struct dlm_rsb, res_hashnode);
-		if (!rsb_flag(r, RSB_LOCKS_PURGED))
+
+		if (!rsb_flag(r, RSB_RECOVER_GRANT))
+			continue;
+		rsb_clear_flag(r, RSB_RECOVER_GRANT);
+		if (!is_master(r))
 			continue;
 		hold_rsb(r);
-		rsb_clear_flag(r, RSB_LOCKS_PURGED);
-		r_ret = r;
-		break;
+		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
+		return r;
 	}
 	spin_unlock(&ls->ls_rsbtbl[bucket].lock);
-	return r_ret;
+	return NULL;
 }
 
-void dlm_grant_after_purge(struct dlm_ls *ls)
+/*
+ * Attempt to grant locks on resources that we are the master of.
+ * Locks may have become grantable during recovery because locks
+ * from departed nodes have been purged (or not rebuilt), allowing
+ * previously blocked locks to now be granted.  The subset of rsb's
+ * we are interested in are those with lkb's on either the convert or
+ * waiting queues.
+ *
+ * Simplest would be to go through each master rsb and check for non-empty
+ * convert or waiting queues, and attempt to grant on those rsbs.
+ * Checking the queues requires lock_rsb, though, for which we'd need
+ * to release the rsbtbl lock.  This would make iterating through all
+ * rsb's very inefficient.  So, we rely on earlier recovery routines
+ * to set RECOVER_GRANT on any rsb's that we should attempt to grant
+ * locks for.
+ */
+
+void dlm_recover_grant(struct dlm_ls *ls)
 {
 	struct dlm_rsb *r;
 	int bucket = 0;
+	unsigned int count = 0;
+	unsigned int rsb_count = 0;
+	unsigned int lkb_count = 0;
 
 	while (1) {
-		r = find_purged_rsb(ls, bucket);
+		r = find_grant_rsb(ls, bucket);
 		if (!r) {
 			if (bucket == ls->ls_rsbtbl_size - 1)
 				break;
 			bucket++;
 			continue;
 		}
+		rsb_count++;
+		count = 0;
 		lock_rsb(r);
-		if (is_master(r)) {
-			grant_pending_locks(r);
-			confirm_master(r, 0);
-		}
+		grant_pending_locks(r, &count);
+		lkb_count += count;
+		confirm_master(r, 0);
 		unlock_rsb(r);
 		put_rsb(r);
-		schedule();
+		cond_resched();
 	}
+
+	if (lkb_count)
+		log_debug(ls, "dlm_recover_grant %u locks on %u resources",
+			  lkb_count, rsb_count);
 }
 
 static struct dlm_lkb *search_remid_list(struct list_head *head, int nodeid,
@@ -4723,11 +4807,26 @@ int dlm_recover_master_copy(struct dlm_ls *ls, struct dlm_rcom *rc)
 
 	remid = le32_to_cpu(rl->rl_lkid);
 
-	error = find_rsb(ls, rl->rl_name, le16_to_cpu(rl->rl_namelen),
-			 R_MASTER, &r);
+	/* In general we expect the rsb returned to be R_MASTER, but we don't
+	   have to require it.  Recovery of masters on one node can overlap
+	   recovery of locks on another node, so one node can send us MSTCPY
+	   locks before we've made ourselves master of this rsb.  We can still
+	   add new MSTCPY locks that we receive here without any harm; when
+	   we make ourselves master, dlm_recover_masters() won't touch the
+	   MSTCPY locks we've received early. */
+
+	error = find_rsb(ls, rl->rl_name, le16_to_cpu(rl->rl_namelen), 0, &r);
 	if (error)
 		goto out;
 
+	if (dlm_no_directory(ls) && (dlm_dir_nodeid(r) != dlm_our_nodeid())) {
+		log_error(ls, "dlm_recover_master_copy remote %d %x not dir",
+			  rc->rc_header.h_nodeid, remid);
+		error = -EBADR;
+		put_rsb(r);
+		goto out;
+	}
+
 	lock_rsb(r);
 
 	lkb = search_remid(r, rc->rc_header.h_nodeid, remid);
@@ -4749,12 +4848,18 @@ int dlm_recover_master_copy(struct dlm_ls *ls, struct dlm_rcom *rc)
 	attach_lkb(r, lkb);
 	add_lkb(r, lkb, rl->rl_status);
 	error = 0;
+	ls->ls_recover_locks_in++;
+
+	if (!list_empty(&r->res_waitqueue) || !list_empty(&r->res_convertqueue))
+		rsb_set_flag(r, RSB_RECOVER_GRANT);
 
  out_remid:
 	/* this is the new value returned to the lock holder for
 	   saving in its process-copy lkb */
 	rl->rl_remid = cpu_to_le32(lkb->lkb_id);
 
+	lkb->lkb_recover_seq = ls->ls_recover_seq;
+
  out_unlock:
 	unlock_rsb(r);
 	put_rsb(r);
@@ -4786,17 +4891,20 @@ int dlm_recover_process_copy(struct dlm_ls *ls, struct dlm_rcom *rc)
 		return error;
 	}
 
+	r = lkb->lkb_resource;
+	hold_rsb(r);
+	lock_rsb(r);
+
 	if (!is_process_copy(lkb)) {
 		log_error(ls, "dlm_recover_process_copy bad %x remote %d %x %d",
 			  lkid, rc->rc_header.h_nodeid, remid, result);
-		dlm_print_lkb(lkb);
+		dlm_dump_rsb(r);
+		unlock_rsb(r);
+		put_rsb(r);
+		dlm_put_lkb(lkb);
 		return -EINVAL;
 	}
 
-	r = lkb->lkb_resource;
-	hold_rsb(r);
-	lock_rsb(r);
-
 	switch (result) {
 	case -EBADR:
 		/* There's a chance the new master received our lock before
diff --git a/fs/dlm/lock.h b/fs/dlm/lock.h
index 56e2bc646565..c8b226c62807 100644
--- a/fs/dlm/lock.h
+++ b/fs/dlm/lock.h
@@ -32,9 +32,9 @@ void dlm_adjust_timeouts(struct dlm_ls *ls);
 int dlm_search_rsb_tree(struct rb_root *tree, char *name, int len,
 			unsigned int flags, struct dlm_rsb **r_ret);
 
-int dlm_purge_locks(struct dlm_ls *ls);
+void dlm_recover_purge(struct dlm_ls *ls);
 void dlm_purge_mstcpy_locks(struct dlm_rsb *r);
-void dlm_grant_after_purge(struct dlm_ls *ls);
+void dlm_recover_grant(struct dlm_ls *ls);
 int dlm_recover_waiters_post(struct dlm_ls *ls);
 void dlm_recover_waiters_pre(struct dlm_ls *ls);
 int dlm_recover_master_copy(struct dlm_ls *ls, struct dlm_rcom *rc);
diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
index a1ea25face82..ca506abbdd3b 100644
--- a/fs/dlm/lockspace.c
+++ b/fs/dlm/lockspace.c
@@ -74,6 +74,19 @@ static ssize_t dlm_id_store(struct dlm_ls *ls, const char *buf, size_t len)
 	return len;
 }
 
+static ssize_t dlm_nodir_show(struct dlm_ls *ls, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%u\n", dlm_no_directory(ls));
+}
+
+static ssize_t dlm_nodir_store(struct dlm_ls *ls, const char *buf, size_t len)
+{
+	int val = simple_strtoul(buf, NULL, 0);
+	if (val == 1)
+		set_bit(LSFL_NODIR, &ls->ls_flags);
+	return len;
+}
+
 static ssize_t dlm_recover_status_show(struct dlm_ls *ls, char *buf)
 {
 	uint32_t status = dlm_recover_status(ls);
@@ -107,6 +120,12 @@ static struct dlm_attr dlm_attr_id = {
 	.store = dlm_id_store
 };
 
+static struct dlm_attr dlm_attr_nodir = {
+	.attr  = {.name = "nodir", .mode = S_IRUGO | S_IWUSR},
+	.show  = dlm_nodir_show,
+	.store = dlm_nodir_store
+};
+
 static struct dlm_attr dlm_attr_recover_status = {
 	.attr  = {.name = "recover_status", .mode = S_IRUGO},
 	.show  = dlm_recover_status_show
@@ -121,6 +140,7 @@ static struct attribute *dlm_attrs[] = {
 	&dlm_attr_control.attr,
 	&dlm_attr_event.attr,
 	&dlm_attr_id.attr,
+	&dlm_attr_nodir.attr,
 	&dlm_attr_recover_status.attr,
 	&dlm_attr_recover_nodeid.attr,
 	NULL,
diff --git a/fs/dlm/rcom.c b/fs/dlm/rcom.c
index 6565fd5e28ef..64d3e2b958c7 100644
--- a/fs/dlm/rcom.c
+++ b/fs/dlm/rcom.c
@@ -492,30 +492,41 @@ int dlm_send_ls_not_ready(int nodeid, struct dlm_rcom *rc_in)
 void dlm_receive_rcom(struct dlm_ls *ls, struct dlm_rcom *rc, int nodeid)
 {
 	int lock_size = sizeof(struct dlm_rcom) + sizeof(struct rcom_lock);
-	int stop, reply = 0;
+	int stop, reply = 0, lock = 0;
+	uint32_t status;
 	uint64_t seq;
 
 	switch (rc->rc_type) {
+	case DLM_RCOM_LOCK:
+		lock = 1;
+		break;
+	case DLM_RCOM_LOCK_REPLY:
+		lock = 1;
+		reply = 1;
+		break;
 	case DLM_RCOM_STATUS_REPLY:
 	case DLM_RCOM_NAMES_REPLY:
 	case DLM_RCOM_LOOKUP_REPLY:
-	case DLM_RCOM_LOCK_REPLY:
 		reply = 1;
 	};
 
 	spin_lock(&ls->ls_recover_lock);
+	status = ls->ls_recover_status;
 	stop = test_bit(LSFL_RECOVERY_STOP, &ls->ls_flags);
 	seq = ls->ls_recover_seq;
 	spin_unlock(&ls->ls_recover_lock);
 
 	if ((stop && (rc->rc_type != DLM_RCOM_STATUS)) ||
-	    (reply && (rc->rc_seq_reply != seq))) {
+	    (reply && (rc->rc_seq_reply != seq)) ||
+	    (lock && !(status & DLM_RS_DIR))) {
 		log_limit(ls, "dlm_receive_rcom ignore msg %d "
-			  "from %d %llu %llu seq %llu",
-			   rc->rc_type, nodeid,
+			  "from %d %llu %llu recover seq %llu sts %x gen %u",
+			   rc->rc_type,
+			   nodeid,
 			   (unsigned long long)rc->rc_seq,
 			   (unsigned long long)rc->rc_seq_reply,
-			   (unsigned long long)seq);
+			   (unsigned long long)seq,
+			   status, ls->ls_generation);
 		goto out;
 	}
 
diff --git a/fs/dlm/recover.c b/fs/dlm/recover.c
index 34d5adf1fce7..7554e4dac6bb 100644
--- a/fs/dlm/recover.c
+++ b/fs/dlm/recover.c
@@ -339,9 +339,12 @@ static void set_lock_master(struct list_head *queue, int nodeid)
 {
 	struct dlm_lkb *lkb;
 
-	list_for_each_entry(lkb, queue, lkb_statequeue)
-		if (!(lkb->lkb_flags & DLM_IFL_MSTCPY))
+	list_for_each_entry(lkb, queue, lkb_statequeue) {
+		if (!(lkb->lkb_flags & DLM_IFL_MSTCPY)) {
 			lkb->lkb_nodeid = nodeid;
+			lkb->lkb_remid = 0;
+		}
+	}
 }
 
 static void set_master_lkbs(struct dlm_rsb *r)
@@ -354,18 +357,16 @@ static void set_master_lkbs(struct dlm_rsb *r)
 /*
  * Propagate the new master nodeid to locks
  * The NEW_MASTER flag tells dlm_recover_locks() which rsb's to consider.
- * The NEW_MASTER2 flag tells recover_lvb() and set_locks_purged() which
+ * The NEW_MASTER2 flag tells recover_lvb() and recover_grant() which
  * rsb's to consider.
  */
 
 static void set_new_master(struct dlm_rsb *r, int nodeid)
 {
-	lock_rsb(r);
 	r->res_nodeid = nodeid;
 	set_master_lkbs(r);
 	rsb_set_flag(r, RSB_NEW_MASTER);
 	rsb_set_flag(r, RSB_NEW_MASTER2);
-	unlock_rsb(r);
 }
 
 /*
@@ -376,9 +377,9 @@ static void set_new_master(struct dlm_rsb *r, int nodeid)
 static int recover_master(struct dlm_rsb *r)
 {
 	struct dlm_ls *ls = r->res_ls;
-	int error, dir_nodeid, ret_nodeid, our_nodeid = dlm_our_nodeid();
-
-	dir_nodeid = dlm_dir_nodeid(r);
+	int error, ret_nodeid;
+	int our_nodeid = dlm_our_nodeid();
+	int dir_nodeid = dlm_dir_nodeid(r);
 
 	if (dir_nodeid == our_nodeid) {
 		error = dlm_dir_lookup(ls, our_nodeid, r->res_name,
@@ -388,7 +389,9 @@ static int recover_master(struct dlm_rsb *r)
 
 		if (ret_nodeid == our_nodeid)
 			ret_nodeid = 0;
+		lock_rsb(r);
 		set_new_master(r, ret_nodeid);
+		unlock_rsb(r);
 	} else {
 		recover_list_add(r);
 		error = dlm_send_rcom_lookup(r, dir_nodeid);
@@ -398,24 +401,33 @@ static int recover_master(struct dlm_rsb *r)
 }
 
 /*
- * When not using a directory, most resource names will hash to a new static
- * master nodeid and the resource will need to be remastered.
+ * All MSTCPY locks are purged and rebuilt, even if the master stayed the same.
+ * This is necessary because recovery can be started, aborted and restarted,
+ * causing the master nodeid to briefly change during the aborted recovery, and
+ * change back to the original value in the second recovery.  The MSTCPY locks
+ * may or may not have been purged during the aborted recovery.  Another node
+ * with an outstanding request in waiters list and a request reply saved in the
+ * requestqueue, cannot know whether it should ignore the reply and resend the
+ * request, or accept the reply and complete the request.  It must do the
+ * former if the remote node purged MSTCPY locks, and it must do the later if
+ * the remote node did not.  This is solved by always purging MSTCPY locks, in
+ * which case, the request reply would always be ignored and the request
+ * resent.
  */
 
 static int recover_master_static(struct dlm_rsb *r)
 {
-	int master = dlm_dir_nodeid(r);
+	int dir_nodeid = dlm_dir_nodeid(r);
+	int new_master = dir_nodeid;
 
-	if (master == dlm_our_nodeid())
-		master = 0;
+	if (dir_nodeid == dlm_our_nodeid())
+		new_master = 0;
 
-	if (r->res_nodeid != master) {
-		if (is_master(r))
-			dlm_purge_mstcpy_locks(r);
-		set_new_master(r, master);
-		return 1;
-	}
-	return 0;
+	lock_rsb(r);
+	dlm_purge_mstcpy_locks(r);
+	set_new_master(r, new_master);
+	unlock_rsb(r);
+	return 1;
 }
 
 /*
@@ -481,7 +493,9 @@ int dlm_recover_master_reply(struct dlm_ls *ls, struct dlm_rcom *rc)
 	if (nodeid == dlm_our_nodeid())
 		nodeid = 0;
 
+	lock_rsb(r);
 	set_new_master(r, nodeid);
+	unlock_rsb(r);
 	recover_list_del(r);
 
 	if (recover_list_empty(ls))
@@ -556,8 +570,6 @@ int dlm_recover_locks(struct dlm_ls *ls)
 	struct dlm_rsb *r;
 	int error, count = 0;
 
-	log_debug(ls, "dlm_recover_locks");
-
 	down_read(&ls->ls_root_sem);
 	list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
 		if (is_master(r)) {
@@ -584,7 +596,7 @@ int dlm_recover_locks(struct dlm_ls *ls)
 	}
 	up_read(&ls->ls_root_sem);
 
-	log_debug(ls, "dlm_recover_locks %d locks", count);
+	log_debug(ls, "dlm_recover_locks %d out", count);
 
 	error = dlm_wait_function(ls, &recover_list_empty);
  out:
@@ -721,21 +733,19 @@ static void recover_conversion(struct dlm_rsb *r)
 }
 
 /* We've become the new master for this rsb and waiting/converting locks may
-   need to be granted in dlm_grant_after_purge() due to locks that may have
+   need to be granted in dlm_recover_grant() due to locks that may have
    existed from a removed node. */
 
-static void set_locks_purged(struct dlm_rsb *r)
+static void recover_grant(struct dlm_rsb *r)
 {
 	if (!list_empty(&r->res_waitqueue) || !list_empty(&r->res_convertqueue))
-		rsb_set_flag(r, RSB_LOCKS_PURGED);
+		rsb_set_flag(r, RSB_RECOVER_GRANT);
 }
 
 void dlm_recover_rsbs(struct dlm_ls *ls)
 {
 	struct dlm_rsb *r;
-	int count = 0;
-
-	log_debug(ls, "dlm_recover_rsbs");
+	unsigned int count = 0;
 
 	down_read(&ls->ls_root_sem);
 	list_for_each_entry(r, &ls->ls_root_list, res_root_list) {
@@ -744,7 +754,7 @@ void dlm_recover_rsbs(struct dlm_ls *ls)
 			if (rsb_flag(r, RSB_RECOVER_CONVERT))
 				recover_conversion(r);
 			if (rsb_flag(r, RSB_NEW_MASTER2))
-				set_locks_purged(r);
+				recover_grant(r);
 			recover_lvb(r);
 			count++;
 		}
@@ -754,7 +764,8 @@ void dlm_recover_rsbs(struct dlm_ls *ls)
 	}
 	up_read(&ls->ls_root_sem);
 
-	log_debug(ls, "dlm_recover_rsbs %d rsbs", count);
+	if (count)
+		log_debug(ls, "dlm_recover_rsbs %d done", count);
 }
 
 /* Create a single list of all root rsb's to be used during recovery */
diff --git a/fs/dlm/recoverd.c b/fs/dlm/recoverd.c
index 11351b57c781..f1a9073c0835 100644
--- a/fs/dlm/recoverd.c
+++ b/fs/dlm/recoverd.c
@@ -84,6 +84,8 @@ static int ls_recover(struct dlm_ls *ls, struct dlm_recover *rv)
 		goto fail;
 	}
 
+	ls->ls_recover_locks_in = 0;
+
 	dlm_set_recover_status(ls, DLM_RS_NODES);
 
 	error = dlm_recover_members_wait(ls);
@@ -130,7 +132,7 @@ static int ls_recover(struct dlm_ls *ls, struct dlm_recover *rv)
 		 * Clear lkb's for departed nodes.
 		 */
 
-		dlm_purge_locks(ls);
+		dlm_recover_purge(ls);
 
 		/*
 		 * Get new master nodeid's for rsb's that were mastered on
@@ -161,6 +163,9 @@ static int ls_recover(struct dlm_ls *ls, struct dlm_recover *rv)
 			goto fail;
 		}
 
+		log_debug(ls, "dlm_recover_locks %u in",
+			  ls->ls_recover_locks_in);
+
 		/*
 		 * Finalize state in master rsb's now that all locks can be
 		 * checked.  This includes conversion resolution and lvb
@@ -225,7 +230,7 @@ static int ls_recover(struct dlm_ls *ls, struct dlm_recover *rv)
 		goto fail;
 	}
 
-	dlm_grant_after_purge(ls);
+	dlm_recover_grant(ls);
 
 	log_debug(ls, "dlm_recover %llu generation %u done: %u ms",
 		  (unsigned long long)rv->seq, ls->ls_generation,
diff --git a/fs/dlm/requestqueue.c b/fs/dlm/requestqueue.c
index d3191bf03a68..1695f1b0dd45 100644
--- a/fs/dlm/requestqueue.c
+++ b/fs/dlm/requestqueue.c
@@ -65,6 +65,7 @@ void dlm_add_requestqueue(struct dlm_ls *ls, int nodeid, struct dlm_message *ms)
 int dlm_process_requestqueue(struct dlm_ls *ls)
 {
 	struct rq_entry *e;
+	struct dlm_message *ms;
 	int error = 0;
 
 	mutex_lock(&ls->ls_requestqueue_mutex);
@@ -78,6 +79,14 @@ int dlm_process_requestqueue(struct dlm_ls *ls)
 		e = list_entry(ls->ls_requestqueue.next, struct rq_entry, list);
 		mutex_unlock(&ls->ls_requestqueue_mutex);
 
+		ms = &e->request;
+
+		log_limit(ls, "dlm_process_requestqueue msg %d from %d "
+			  "lkid %x remid %x result %d seq %u",
+			  ms->m_type, ms->m_header.h_nodeid,
+			  ms->m_lkid, ms->m_remid, ms->m_result,
+			  e->recover_seq);
+
 		dlm_receive_message_saved(ls, &e->request, e->recover_seq);
 
 		mutex_lock(&ls->ls_requestqueue_mutex);
@@ -140,35 +149,7 @@ static int purge_request(struct dlm_ls *ls, struct dlm_message *ms, int nodeid)
 	if (!dlm_no_directory(ls))
 		return 0;
 
-	/* with no directory, the master is likely to change as a part of
-	   recovery; requests to/from the defunct master need to be purged */
-
-	switch (type) {
-	case DLM_MSG_REQUEST:
-	case DLM_MSG_CONVERT:
-	case DLM_MSG_UNLOCK:
-	case DLM_MSG_CANCEL:
-		/* we're no longer the master of this resource, the sender
-		   will resend to the new master (see waiter_needs_recovery) */
-
-		if (dlm_hash2nodeid(ls, ms->m_hash) != dlm_our_nodeid())
-			return 1;
-		break;
-
-	case DLM_MSG_REQUEST_REPLY:
-	case DLM_MSG_CONVERT_REPLY:
-	case DLM_MSG_UNLOCK_REPLY:
-	case DLM_MSG_CANCEL_REPLY:
-	case DLM_MSG_GRANT:
-		/* this reply is from the former master of the resource,
-		   we'll resend to the new master if needed */
-
-		if (dlm_hash2nodeid(ls, ms->m_hash) != nodeid)
-			return 1;
-		break;
-	}
-
-	return 0;
+	return 1;
 }
 
 void dlm_purge_requestqueue(struct dlm_ls *ls)