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>

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);
 }
 

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);

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);

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,

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;
 	}
 

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 */

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,

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)

fs/gfs2/incore.h

@@ -556,7 +556,6 @@ struct gfs2_sb_host {
 struct lm_lockstruct {
 	int ls_jid;
 	unsigned int ls_first;
-	unsigned int ls_nodir;
 	const struct lm_lockops *ls_ops;
 	dlm_lockspace_t *ls_dlm;
 

fs/gfs2/lock_dlm.c

@@ -1209,8 +1209,6 @@ static int gdlm_mount(struct gfs2_sbd *sdp, const char *table)
 	fsname++;
 
 	flags = DLM_LSFL_FS | DLM_LSFL_NEWEXCL;
-	if (ls->ls_nodir)
-		flags |= DLM_LSFL_NODIR;
 
 	/*
 	 * create/join lockspace

fs/gfs2/ops_fstype.c

@@ -994,6 +994,7 @@ static int gfs2_lm_mount(struct gfs2_sbd *sdp, int silent)
 				ls->ls_jid = option;
 			break;
 		case Opt_id:
+		case Opt_nodir:
 			/* Obsolete, but left for backward compat purposes */
 			break;
 		case Opt_first:
@@ -1002,12 +1003,6 @@ static int gfs2_lm_mount(struct gfs2_sbd *sdp, int silent)
 				goto hostdata_error;
 			ls->ls_first = option;
 			break;
-		case Opt_nodir:
-			ret = match_int(&tmp[0], &option);
-			if (ret || (option != 0 && option != 1))
-				goto hostdata_error;
-			ls->ls_nodir = option;
-			break;
 		case Opt_err:
 		default:
 hostdata_error:

include/linux/dlm.h

@@ -67,7 +67,6 @@ struct dlm_lksb {
 
 /* dlm_new_lockspace() flags */
 
-#define DLM_LSFL_NODIR		0x00000001
 #define DLM_LSFL_TIMEWARN	0x00000002
 #define DLM_LSFL_FS     	0x00000004
 #define DLM_LSFL_NEWEXCL     	0x00000008