X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=fs%2Fdlm%2Flock.c;h=b56950758188d4b72f4ed2e193047ab1aded8c8b;hb=95b5fa1a3c0e034dc47186e033cf4a4f7fe46214;hp=d9ee1b96549ab8dcab03773b2bd7884353b51823;hpb=c04fecb4d9f7753e0cbff7edd03ec68f8721cdce;p=firefly-linux-kernel-4.4.55.git

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index d9ee1b96549a..b56950758188 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -1624,65 +1624,170 @@ static int remove_from_waiters_ms(struct dlm_lkb *lkb, struct dlm_message *ms)
 	return error;
 }
 
-/* FIXME: make this more efficient */
+/* If there's an rsb for the same resource being removed, ensure
+   that the remove message is sent before the new lookup message.
+   It should be rare to need a delay here, but if not, then it may
+   be worthwhile to add a proper wait mechanism rather than a delay. */
 
-static int shrink_bucket(struct dlm_ls *ls, int b)
+static void wait_pending_remove(struct dlm_rsb *r)
 {
-	struct rb_node *n;
+	struct dlm_ls *ls = r->res_ls;
+ restart:
+	spin_lock(&ls->ls_remove_spin);
+	if (ls->ls_remove_len &&
+	    !rsb_cmp(r, ls->ls_remove_name, ls->ls_remove_len)) {
+		log_debug(ls, "delay lookup for remove dir %d %s",
+		  	  r->res_dir_nodeid, r->res_name);
+		spin_unlock(&ls->ls_remove_spin);
+		msleep(1);
+		goto restart;
+	}
+	spin_unlock(&ls->ls_remove_spin);
+}
+
+/*
+ * ls_remove_spin protects ls_remove_name and ls_remove_len which are
+ * read by other threads in wait_pending_remove.  ls_remove_names
+ * and ls_remove_lens are only used by the scan thread, so they do
+ * not need protection.
+ */
+
+static void shrink_bucket(struct dlm_ls *ls, int b)
+{
+	struct rb_node *n, *next;
 	struct dlm_rsb *r;
+	char *name;
 	int our_nodeid = dlm_our_nodeid();
-	int count = 0, found;
+	int remote_count = 0;
+	int i, len, rv;
 
-	for (;;) {
-		found = 0;
-		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);
+	memset(&ls->ls_remove_lens, 0, sizeof(int) * DLM_REMOVE_NAMES_MAX);
 
-			/* 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. */
+	spin_lock(&ls->ls_rsbtbl[b].lock);
+	for (n = rb_first(&ls->ls_rsbtbl[b].toss); n; n = next) {
+		next = rb_next(n);
+		r = rb_entry(n, struct dlm_rsb, res_hashnode);
 
-			if (!dlm_no_directory(ls) && !is_master(r) &&
-			    (dlm_dir_nodeid(r) == our_nodeid)) {
-				continue;
-			}
+		/* 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 (!time_after_eq(jiffies, r->res_toss_time +
-					   dlm_config.ci_toss_secs * HZ))
-				continue;
-			found = 1;
-			break;
+		if (!dlm_no_directory(ls) &&
+		    (r->res_master_nodeid != our_nodeid) &&
+		    (dlm_dir_nodeid(r) == our_nodeid)) {
+			continue;
 		}
 
-		if (!found) {
-			spin_unlock(&ls->ls_rsbtbl[b].lock);
-			break;
+		if (!time_after_eq(jiffies, r->res_toss_time +
+				   dlm_config.ci_toss_secs * HZ)) {
+			continue;
 		}
 
-		if (kref_put(&r->res_ref, kill_rsb)) {
-			rb_erase(&r->res_hashnode, &ls->ls_rsbtbl[b].toss);
-			spin_unlock(&ls->ls_rsbtbl[b].lock);
+		if (!dlm_no_directory(ls) &&
+		    (r->res_master_nodeid == our_nodeid) &&
+		    (dlm_dir_nodeid(r) != our_nodeid)) {
 
 			/* 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);
-			}
+			ls->ls_remove_lens[remote_count] = r->res_length;
+			memcpy(ls->ls_remove_names[remote_count], r->res_name,
+			       DLM_RESNAME_MAXLEN);
+			remote_count++;
 
-			dlm_free_rsb(r);
-			count++;
-		} else {
-			spin_unlock(&ls->ls_rsbtbl[b].lock);
+			if (remote_count >= DLM_REMOVE_NAMES_MAX)
+				break;
+			continue;
+		}
+
+		if (!kref_put(&r->res_ref, kill_rsb)) {
 			log_error(ls, "tossed rsb in use %s", r->res_name);
+			continue;
 		}
+
+		rb_erase(&r->res_hashnode, &ls->ls_rsbtbl[b].toss);
+		dlm_free_rsb(r);
 	}
+	spin_unlock(&ls->ls_rsbtbl[b].lock);
+
+	/*
+	 * While searching for rsb's to free, we found some that require
+	 * remote removal.  We leave them in place and find them again here
+	 * so there is a very small gap between removing them from the toss
+	 * list and sending the removal.  Keeping this gap small is
+	 * important to keep us (the master node) from being out of sync
+	 * with the remote dir node for very long.
+	 *
+	 * From the time the rsb is removed from toss until just after
+	 * send_remove, the rsb name is saved in ls_remove_name.  A new
+	 * lookup checks this to ensure that a new lookup message for the
+	 * same resource name is not sent just before the remove message.
+	 */
+
+	for (i = 0; i < remote_count; i++) {
+		name = ls->ls_remove_names[i];
+		len = ls->ls_remove_lens[i];
+
+		spin_lock(&ls->ls_rsbtbl[b].lock);
+		rv = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].toss, name, len, &r);
+		if (rv) {
+			spin_unlock(&ls->ls_rsbtbl[b].lock);
+			log_debug(ls, "remove_name not toss %s", name);
+			continue;
+		}
 
-	return count;
+		if (r->res_master_nodeid != our_nodeid) {
+			spin_unlock(&ls->ls_rsbtbl[b].lock);
+			log_debug(ls, "remove_name master %d dir %d our %d %s",
+				  r->res_master_nodeid, r->res_dir_nodeid,
+				  our_nodeid, name);
+			continue;
+		}
+
+		if (r->res_dir_nodeid == our_nodeid) {
+			/* should never happen */
+			spin_unlock(&ls->ls_rsbtbl[b].lock);
+			log_error(ls, "remove_name dir %d master %d our %d %s",
+				  r->res_dir_nodeid, r->res_master_nodeid,
+				  our_nodeid, name);
+			continue;
+		}
+
+		if (!time_after_eq(jiffies, r->res_toss_time +
+				   dlm_config.ci_toss_secs * HZ)) {
+			spin_unlock(&ls->ls_rsbtbl[b].lock);
+			log_debug(ls, "remove_name toss_time %lu now %lu %s",
+				  r->res_toss_time, jiffies, name);
+			continue;
+		}
+
+		if (!kref_put(&r->res_ref, kill_rsb)) {
+			spin_unlock(&ls->ls_rsbtbl[b].lock);
+			log_error(ls, "remove_name in use %s", name);
+			continue;
+		}
+
+		rb_erase(&r->res_hashnode, &ls->ls_rsbtbl[b].toss);
+
+		/* block lookup of same name until we've sent remove */
+		spin_lock(&ls->ls_remove_spin);
+		ls->ls_remove_len = len;
+		memcpy(ls->ls_remove_name, name, DLM_RESNAME_MAXLEN);
+		spin_unlock(&ls->ls_remove_spin);
+		spin_unlock(&ls->ls_rsbtbl[b].lock);
+
+		send_remove(r);
+
+		/* allow lookup of name again */
+		spin_lock(&ls->ls_remove_spin);
+		ls->ls_remove_len = 0;
+		memset(ls->ls_remove_name, 0, DLM_RESNAME_MAXLEN);
+		spin_unlock(&ls->ls_remove_spin);
+
+		dlm_free_rsb(r);
+	}
 }
 
 void dlm_scan_rsbs(struct dlm_ls *ls)
@@ -2174,10 +2279,14 @@ static int conversion_deadlock_detect(struct dlm_rsb *r, struct dlm_lkb *lkb2)
  * immediate request, it is 0 if called later, after the lock has been
  * queued.
  *
+ * recover is 1 if dlm_recover_grant() is trying to grant conversions
+ * after recovery.
+ *
  * References are from chapter 6 of "VAXcluster Principles" by Roy Davis
  */
 
-static int _can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now)
+static int _can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now,
+			   int recover)
 {
 	int8_t conv = (lkb->lkb_grmode != DLM_LOCK_IV);
 
@@ -2209,7 +2318,7 @@ static int _can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now)
 	 */
 
 	if (queue_conflict(&r->res_grantqueue, lkb))
-		goto out;
+		return 0;
 
 	/*
 	 * 6-3: By default, a conversion request is immediately granted if the
@@ -2218,7 +2327,24 @@ static int _can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now)
 	 */
 
 	if (queue_conflict(&r->res_convertqueue, lkb))
-		goto out;
+		return 0;
+
+	/*
+	 * The RECOVER_GRANT flag means dlm_recover_grant() is granting
+	 * locks for a recovered rsb, on which lkb's have been rebuilt.
+	 * The lkb's may have been rebuilt on the queues in a different
+	 * order than they were in on the previous master.  So, granting
+	 * queued conversions in order after recovery doesn't make sense
+	 * since the order hasn't been preserved anyway.  The new order
+	 * could also have created a new "in place" conversion deadlock.
+	 * (e.g. old, failed master held granted EX, with PR->EX, NL->EX.
+	 * After recovery, there would be no granted locks, and possibly
+	 * NL->EX, PR->EX, an in-place conversion deadlock.)  So, after
+	 * recovery, grant conversions without considering order.
+	 */
+
+	if (conv && recover)
+		return 1;
 
 	/*
 	 * 6-5: But the default algorithm for deciding whether to grant or
@@ -2255,7 +2381,7 @@ static int _can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now)
 		if (list_empty(&r->res_convertqueue))
 			return 1;
 		else
-			goto out;
+			return 0;
 	}
 
 	/*
@@ -2301,12 +2427,12 @@ static int _can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now)
 	if (!now && !conv && list_empty(&r->res_convertqueue) &&
 	    first_in_list(lkb, &r->res_waitqueue))
 		return 1;
- out:
+
 	return 0;
 }
 
 static int can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now,
-			  int *err)
+			  int recover, int *err)
 {
 	int rv;
 	int8_t alt = 0, rqmode = lkb->lkb_rqmode;
@@ -2315,7 +2441,7 @@ static int can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now,
 	if (err)
 		*err = 0;
 
-	rv = _can_be_granted(r, lkb, now);
+	rv = _can_be_granted(r, lkb, now, recover);
 	if (rv)
 		goto out;
 
@@ -2356,7 +2482,7 @@ static int can_be_granted(struct dlm_rsb *r, struct dlm_lkb *lkb, int now,
 
 	if (alt) {
 		lkb->lkb_rqmode = alt;
-		rv = _can_be_granted(r, lkb, now);
+		rv = _can_be_granted(r, lkb, now, 0);
 		if (rv)
 			lkb->lkb_sbflags |= DLM_SBF_ALTMODE;
 		else
@@ -2380,6 +2506,7 @@ static int grant_pending_convert(struct dlm_rsb *r, int high, int *cw,
 				 unsigned int *count)
 {
 	struct dlm_lkb *lkb, *s;
+	int recover = rsb_flag(r, RSB_RECOVER_GRANT);
 	int hi, demoted, quit, grant_restart, demote_restart;
 	int deadlk;
 
@@ -2393,7 +2520,7 @@ static int grant_pending_convert(struct dlm_rsb *r, int high, int *cw,
 		demoted = is_demoted(lkb);
 		deadlk = 0;
 
-		if (can_be_granted(r, lkb, 0, &deadlk)) {
+		if (can_be_granted(r, lkb, 0, recover, &deadlk)) {
 			grant_lock_pending(r, lkb);
 			grant_restart = 1;
 			if (count)
@@ -2437,7 +2564,7 @@ static int grant_pending_wait(struct dlm_rsb *r, int high, int *cw,
 	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, 0, NULL)) {
 			grant_lock_pending(r, lkb);
 			if (count)
 				(*count)++;
@@ -2608,6 +2735,8 @@ static int set_master(struct dlm_rsb *r, struct dlm_lkb *lkb)
 		return 0;
 	}
 
+	wait_pending_remove(r);
+
 	r->res_first_lkid = lkb->lkb_id;
 	send_lookup(r, lkb);
 	return 1;
@@ -2935,7 +3064,7 @@ static int do_request(struct dlm_rsb *r, struct dlm_lkb *lkb)
 {
 	int error = 0;
 
-	if (can_be_granted(r, lkb, 1, NULL)) {
+	if (can_be_granted(r, lkb, 1, 0, NULL)) {
 		grant_lock(r, lkb);
 		queue_cast(r, lkb, 0);
 		goto out;
@@ -2975,7 +3104,7 @@ static int do_convert(struct dlm_rsb *r, struct dlm_lkb *lkb)
 
 	/* changing an existing lock may allow others to be granted */
 
-	if (can_be_granted(r, lkb, 1, &deadlk)) {
+	if (can_be_granted(r, lkb, 1, 0, &deadlk)) {
 		grant_lock(r, lkb);
 		queue_cast(r, lkb, 0);
 		goto out;
@@ -3001,7 +3130,7 @@ static int do_convert(struct dlm_rsb *r, struct dlm_lkb *lkb)
 
 	if (is_demoted(lkb)) {
 		grant_pending_convert(r, DLM_LOCK_IV, NULL, NULL);
-		if (_can_be_granted(r, lkb, 1)) {
+		if (_can_be_granted(r, lkb, 1, 0)) {
 			grant_lock(r, lkb);
 			queue_cast(r, lkb, 0);
 			goto out;
@@ -3871,12 +4000,70 @@ static int validate_message(struct dlm_lkb *lkb, struct dlm_message *ms)
 	return error;
 }
 
+static void send_repeat_remove(struct dlm_ls *ls, char *ms_name, int len)
+{
+	char name[DLM_RESNAME_MAXLEN + 1];
+	struct dlm_message *ms;
+	struct dlm_mhandle *mh;
+	struct dlm_rsb *r;
+	uint32_t hash, b;
+	int rv, dir_nodeid;
+
+	memset(name, 0, sizeof(name));
+	memcpy(name, ms_name, len);
+
+	hash = jhash(name, len, 0);
+	b = hash & (ls->ls_rsbtbl_size - 1);
+
+	dir_nodeid = dlm_hash2nodeid(ls, hash);
+
+	log_error(ls, "send_repeat_remove dir %d %s", dir_nodeid, name);
+
+	spin_lock(&ls->ls_rsbtbl[b].lock);
+	rv = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].keep, name, len, &r);
+	if (!rv) {
+		spin_unlock(&ls->ls_rsbtbl[b].lock);
+		log_error(ls, "repeat_remove on keep %s", name);
+		return;
+	}
+
+	rv = dlm_search_rsb_tree(&ls->ls_rsbtbl[b].toss, name, len, &r);
+	if (!rv) {
+		spin_unlock(&ls->ls_rsbtbl[b].lock);
+		log_error(ls, "repeat_remove on toss %s", name);
+		return;
+	}
+
+	/* use ls->remove_name2 to avoid conflict with shrink? */
+
+	spin_lock(&ls->ls_remove_spin);
+	ls->ls_remove_len = len;
+	memcpy(ls->ls_remove_name, name, DLM_RESNAME_MAXLEN);
+	spin_unlock(&ls->ls_remove_spin);
+	spin_unlock(&ls->ls_rsbtbl[b].lock);
+
+	rv = _create_message(ls, sizeof(struct dlm_message) + len,
+			     dir_nodeid, DLM_MSG_REMOVE, &ms, &mh);
+	if (rv)
+		return;
+
+	memcpy(ms->m_extra, name, len);
+	ms->m_hash = hash;
+
+	send_message(mh, ms);
+
+	spin_lock(&ls->ls_remove_spin);
+	ls->ls_remove_len = 0;
+	memset(ls->ls_remove_name, 0, DLM_RESNAME_MAXLEN);
+	spin_unlock(&ls->ls_remove_spin);
+}
+
 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;
+	int error, namelen = 0;
 
 	from_nodeid = ms->m_header.h_nodeid;
 
@@ -3944,13 +4131,21 @@ static int receive_request(struct dlm_ls *ls, struct dlm_message *ms)
 	   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. */
+	   took effect.
+
+	   We send another remove message in case our previous send_remove
+	   was lost/ignored/missed somehow. */
 
 	if (error != -ENOTBLK) {
 		log_limit(ls, "receive_request %x from %d %d",
 			  ms->m_lkid, from_nodeid, error);
 	}
 
+	if (namelen && error == -EBADR) {
+		send_repeat_remove(ls, ms->m_extra, namelen);
+		msleep(1000);
+	}
+
 	setup_stub_lkb(ls, ms);
 	send_request_reply(&ls->ls_stub_rsb, &ls->ls_stub_lkb, error);
 	return error;
@@ -5266,9 +5461,10 @@ static struct dlm_rsb *find_grant_rsb(struct dlm_ls *ls, int bucket)
 
 		if (!rsb_flag(r, RSB_RECOVER_GRANT))
 			continue;
-		rsb_clear_flag(r, RSB_RECOVER_GRANT);
-		if (!is_master(r))
+		if (!is_master(r)) {
+			rsb_clear_flag(r, RSB_RECOVER_GRANT);
 			continue;
+		}
 		hold_rsb(r);
 		spin_unlock(&ls->ls_rsbtbl[bucket].lock);
 		return r;
@@ -5313,7 +5509,9 @@ void dlm_recover_grant(struct dlm_ls *ls)
 		rsb_count++;
 		count = 0;
 		lock_rsb(r);
+		/* the RECOVER_GRANT flag is checked in the grant path */
 		grant_pending_locks(r, &count);
+		rsb_clear_flag(r, RSB_RECOVER_GRANT);
 		lkb_count += count;
 		confirm_master(r, 0);
 		unlock_rsb(r);