1 files changed, 100 insertions, 41 deletions

diff --git a/drivers/md/bcache/journal.c b/drivers/md/bcache/journal.c
index 12dae9348147..be2a2a201603 100644
--- a/drivers/md/bcache/journal.c
+++ b/drivers/md/bcache/journal.c
@@ -100,6 +100,20 @@ reread:		left = ca->sb.bucket_size - offset;
 
 			blocks = set_blocks(j, block_bytes(ca->set));
 
+			/*
+			 * Nodes in 'list' are in linear increasing order of
+			 * i->j.seq, the node on head has the smallest (oldest)
+			 * journal seq, the node on tail has the biggest
+			 * (latest) journal seq.
+			 */
+
+			/*
+			 * Check from the oldest jset for last_seq. If
+			 * i->j.seq < j->last_seq, it means the oldest jset
+			 * in list is expired and useless, remove it from
+			 * this list. Otherwise, j is a condidate jset for
+			 * further following checks.
+			 */
 			while (!list_empty(list)) {
 				i = list_first_entry(list,
 					struct journal_replay, list);
@@ -109,13 +123,22 @@ reread:		left = ca->sb.bucket_size - offset;
 				kfree(i);
 			}
 
+			/* iterate list in reverse order (from latest jset) */
 			list_for_each_entry_reverse(i, list, list) {
 				if (j->seq == i->j.seq)
 					goto next_set;
 
+				/*
+				 * if j->seq is less than any i->j.last_seq
+				 * in list, j is an expired and useless jset.
+				 */
 				if (j->seq < i->j.last_seq)
 					goto next_set;
 
+				/*
+				 * 'where' points to first jset in list which
+				 * is elder then j.
+				 */
 				if (j->seq > i->j.seq) {
 					where = &i->list;
 					goto add;
@@ -129,10 +152,12 @@ add:
 			if (!i)
 				return -ENOMEM;
 			memcpy(&i->j, j, bytes);
+			/* Add to the location after 'where' points to */
 			list_add(&i->list, where);
 			ret = 1;
 
-			ja->seq[bucket_index] = j->seq;
+			if (j->seq > ja->seq[bucket_index])
+				ja->seq[bucket_index] = j->seq;
 next_set:
 			offset	+= blocks * ca->sb.block_size;
 			len	-= blocks * ca->sb.block_size;
@@ -268,7 +293,7 @@ bsearch:
 					    struct journal_replay,
 					    list)->j.seq;
 
-	return ret;
+	return 0;
 #undef read_bucket
 }
 
@@ -391,60 +416,90 @@ err:
 }
 
 /* Journalling */
-#define journal_max_cmp(l, r) \
-	(fifo_idx(&c->journal.pin, btree_current_write(l)->journal) < \
-	 fifo_idx(&(c)->journal.pin, btree_current_write(r)->journal))
-#define journal_min_cmp(l, r) \
-	(fifo_idx(&c->journal.pin, btree_current_write(l)->journal) > \
-	 fifo_idx(&(c)->journal.pin, btree_current_write(r)->journal))
 
 static void btree_flush_write(struct cache_set *c)
 {
-	/*
-	 * Try to find the btree node with that references the oldest journal
-	 * entry, best is our current candidate and is locked if non NULL:
-	 */
-	struct btree *b;
-	int i;
+	struct btree *b, *t, *btree_nodes[BTREE_FLUSH_NR];
+	unsigned int i, n;
+
+	if (c->journal.btree_flushing)
+		return;
+
+	spin_lock(&c->journal.flush_write_lock);
+	if (c->journal.btree_flushing) {
+		spin_unlock(&c->journal.flush_write_lock);
+		return;
+	}
+	c->journal.btree_flushing = true;
+	spin_unlock(&c->journal.flush_write_lock);
 
 	atomic_long_inc(&c->flush_write);
+	memset(btree_nodes, 0, sizeof(btree_nodes));
+	n = 0;
 
-retry:
-	spin_lock(&c->journal.lock);
-	if (heap_empty(&c->flush_btree)) {
-		for_each_cached_btree(b, c, i)
-			if (btree_current_write(b)->journal) {
-				if (!heap_full(&c->flush_btree))
-					heap_add(&c->flush_btree, b,
-						 journal_max_cmp);
-				else if (journal_max_cmp(b,
-					 heap_peek(&c->flush_btree))) {
-					c->flush_btree.data[0] = b;
-					heap_sift(&c->flush_btree, 0,
-						  journal_max_cmp);
-				}
-			}
+	mutex_lock(&c->bucket_lock);
+	list_for_each_entry_safe_reverse(b, t, &c->btree_cache, list) {
+		if (btree_node_journal_flush(b))
+			pr_err("BUG: flush_write bit should not be set here!");
+
+		mutex_lock(&b->write_lock);
 
-		for (i = c->flush_btree.used / 2 - 1; i >= 0; --i)
-			heap_sift(&c->flush_btree, i, journal_min_cmp);
+		if (!btree_node_dirty(b)) {
+			mutex_unlock(&b->write_lock);
+			continue;
+		}
+
+		if (!btree_current_write(b)->journal) {
+			mutex_unlock(&b->write_lock);
+			continue;
+		}
+
+		set_btree_node_journal_flush(b);
+
+		mutex_unlock(&b->write_lock);
+
+		btree_nodes[n++] = b;
+		if (n == BTREE_FLUSH_NR)
+			break;
 	}
+	mutex_unlock(&c->bucket_lock);
 
-	b = NULL;
-	heap_pop(&c->flush_btree, b, journal_min_cmp);
-	spin_unlock(&c->journal.lock);
+	for (i = 0; i < n; i++) {
+		b = btree_nodes[i];
+		if (!b) {
+			pr_err("BUG: btree_nodes[%d] is NULL", i);
+			continue;
+		}
+
+		/* safe to check without holding b->write_lock */
+		if (!btree_node_journal_flush(b)) {
+			pr_err("BUG: bnode %p: journal_flush bit cleaned", b);
+			continue;
+		}
 
-	if (b) {
 		mutex_lock(&b->write_lock);
 		if (!btree_current_write(b)->journal) {
+			clear_bit(BTREE_NODE_journal_flush, &b->flags);
+			mutex_unlock(&b->write_lock);
+			pr_debug("bnode %p: written by others", b);
+			continue;
+		}
+
+		if (!btree_node_dirty(b)) {
+			clear_bit(BTREE_NODE_journal_flush, &b->flags);
 			mutex_unlock(&b->write_lock);
-			/* We raced */
-			atomic_long_inc(&c->retry_flush_write);
-			goto retry;
+			pr_debug("bnode %p: dirty bit cleaned by others", b);
+			continue;
 		}
 
 		__bch_btree_node_write(b, NULL);
+		clear_bit(BTREE_NODE_journal_flush, &b->flags);
 		mutex_unlock(&b->write_lock);
 	}
+
+	spin_lock(&c->journal.flush_write_lock);
+	c->journal.btree_flushing = false;
+	spin_unlock(&c->journal.flush_write_lock);
 }
 
 #define last_seq(j)	((j)->seq - fifo_used(&(j)->pin) + 1)
@@ -559,6 +614,7 @@ static void journal_reclaim(struct cache_set *c)
 		k->ptr[n++] = MAKE_PTR(0,
 				  bucket_to_sector(c, ca->sb.d[ja->cur_idx]),
 				  ca->sb.nr_this_dev);
+		atomic_long_inc(&c->reclaimed_journal_buckets);
 	}
 
 	if (n) {
@@ -811,6 +867,10 @@ atomic_t *bch_journal(struct cache_set *c,
 	struct journal_write *w;
 	atomic_t *ret;
 
+	/* No journaling if CACHE_SET_IO_DISABLE set already */
+	if (unlikely(test_bit(CACHE_SET_IO_DISABLE, &c->flags)))
+		return NULL;
+
 	if (!CACHE_SYNC(&c->sb))
 		return NULL;
 
@@ -855,7 +915,6 @@ void bch_journal_free(struct cache_set *c)
 	free_pages((unsigned long) c->journal.w[1].data, JSET_BITS);
 	free_pages((unsigned long) c->journal.w[0].data, JSET_BITS);
 	free_fifo(&c->journal.pin);
-	free_heap(&c->flush_btree);
 }
 
 int bch_journal_alloc(struct cache_set *c)
@@ -863,6 +922,7 @@ int bch_journal_alloc(struct cache_set *c)
 	struct journal *j = &c->journal;
 
 	spin_lock_init(&j->lock);
+	spin_lock_init(&j->flush_write_lock);
 	INIT_DELAYED_WORK(&j->work, journal_write_work);
 
 	c->journal_delay_ms = 100;
@@ -870,8 +930,7 @@ int bch_journal_alloc(struct cache_set *c)
 	j->w[0].c = c;
 	j->w[1].c = c;
 
-	if (!(init_heap(&c->flush_btree, 128, GFP_KERNEL)) ||
-	    !(init_fifo(&j->pin, JOURNAL_PIN, GFP_KERNEL)) ||
+	if (!(init_fifo(&j->pin, JOURNAL_PIN, GFP_KERNEL)) ||
 	    !(j->w[0].data = (void *) __get_free_pages(GFP_KERNEL, JSET_BITS)) ||
 	    !(j->w[1].data = (void *) __get_free_pages(GFP_KERNEL, JSET_BITS)))
 		return -ENOMEM;