bcache: Fix another bug recovering from unclean shutdown

The on disk bucket gens are allowed to be out of date, when we reuse buckets
that didn't have any live data in them. To deal with this, the initial gc has to
update the bucket gen when we find a pointer gen newer than the bucket's gen.

Unfortunately we weren't doing this for pointers in the journal that we're about
to replay.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

drivers/md/bcache/btree.c

@@ -1126,7 +1126,8 @@ static int btree_check_reserve(struct btree *b, struct btree_op *op)
 
 /* Garbage collection */
 
-uint8_t __bch_btree_mark_key(struct cache_set *c, int level, struct bkey *k)
+static uint8_t __bch_btree_mark_key(struct cache_set *c, int level,
+				    struct bkey *k)
 {
 	uint8_t stale = 0;
 	unsigned i;
@@ -1177,6 +1178,26 @@ uint8_t __bch_btree_mark_key(struct cache_set *c, int level, struct bkey *k)
 
 #define btree_mark_key(b, k)	__bch_btree_mark_key(b->c, b->level, k)
 
+void bch_initial_mark_key(struct cache_set *c, int level, struct bkey *k)
+{
+	unsigned i;
+
+	for (i = 0; i < KEY_PTRS(k); i++)
+		if (ptr_available(c, k, i) &&
+		    !ptr_stale(c, k, i)) {
+			struct bucket *b = PTR_BUCKET(c, k, i);
+
+			b->gen = PTR_GEN(k, i);
+
+			if (level && bkey_cmp(k, &ZERO_KEY))
+				b->prio = BTREE_PRIO;
+			else if (!level && b->prio == BTREE_PRIO)
+				b->prio = INITIAL_PRIO;
+		}
+
+	__bch_btree_mark_key(c, level, k);
+}
+
 static bool btree_gc_mark_node(struct btree *b, struct gc_stat *gc)
 {
 	uint8_t stale = 0;
@@ -1511,6 +1532,8 @@ static int bch_btree_gc_root(struct btree *b, struct btree_op *op,
 		}
 	}
 
+	__bch_btree_mark_key(b->c, b->level + 1, &b->key);
+
 	if (b->level) {
 		ret = btree_gc_recurse(b, op, writes, gc);
 		if (ret)
@@ -1561,11 +1584,6 @@ size_t bch_btree_gc_finish(struct cache_set *c)
 	c->gc_mark_valid = 1;
 	c->need_gc	= 0;
 
-	if (c->root)
-		for (i = 0; i < KEY_PTRS(&c->root->key); i++)
-			SET_GC_MARK(PTR_BUCKET(c, &c->root->key, i),
-				    GC_MARK_METADATA);
-
 	for (i = 0; i < KEY_PTRS(&c->uuid_bucket); i++)
 		SET_GC_MARK(PTR_BUCKET(c, &c->uuid_bucket, i),
 			    GC_MARK_METADATA);
@@ -1705,36 +1723,16 @@ int bch_gc_thread_start(struct cache_set *c)
 
 /* Initial partial gc */
 
-static int bch_btree_check_recurse(struct btree *b, struct btree_op *op,
-				   unsigned long **seen)
+static int bch_btree_check_recurse(struct btree *b, struct btree_op *op)
 {
 	int ret = 0;
-	unsigned i;
 	struct bkey *k, *p = NULL;
-	struct bucket *g;
 	struct btree_iter iter;
 
-	for_each_key_filter(&b->keys, k, &iter, bch_ptr_invalid) {
-		for (i = 0; i < KEY_PTRS(k); i++) {
-			if (!ptr_available(b->c, k, i))
-				continue;
+	for_each_key_filter(&b->keys, k, &iter, bch_ptr_invalid)
+		bch_initial_mark_key(b->c, b->level, k);
 
-			g = PTR_BUCKET(b->c, k, i);
-
-			if (!__test_and_set_bit(PTR_BUCKET_NR(b->c, k, i),
-						seen[PTR_DEV(k, i)]) ||
-			    !ptr_stale(b->c, k, i)) {
-				g->gen = PTR_GEN(k, i);
-
-				if (b->level && bkey_cmp(k, &ZERO_KEY))
-					g->prio = BTREE_PRIO;
-				else if (!b->level && g->prio == BTREE_PRIO)
-					g->prio = INITIAL_PRIO;
-			}
-		}
-
-		btree_mark_key(b, k);
-	}
+	bch_initial_mark_key(b->c, b->level + 1, &b->key);
 
 	if (b->level) {
 		bch_btree_iter_init(&b->keys, &iter, NULL);
@@ -1746,40 +1744,22 @@ static int bch_btree_check_recurse(struct btree *b, struct btree_op *op,
 				btree_node_prefetch(b->c, k, b->level - 1);
 
 			if (p)
-				ret = btree(check_recurse, p, b, op, seen);
+				ret = btree(check_recurse, p, b, op);
 
 			p = k;
 		} while (p && !ret);
 	}
 
-	return 0;
+	return ret;
 }
 
 int bch_btree_check(struct cache_set *c)
 {
-	int ret = -ENOMEM;
-	unsigned i;
-	unsigned long *seen[MAX_CACHES_PER_SET];
 	struct btree_op op;
 
-	memset(seen, 0, sizeof(seen));
 	bch_btree_op_init(&op, SHRT_MAX);
 
-	for (i = 0; c->cache[i]; i++) {
-		size_t n = DIV_ROUND_UP(c->cache[i]->sb.nbuckets, 8);
-		seen[i] = kmalloc(n, GFP_KERNEL);
-		if (!seen[i])
-			goto err;
-
-		/* Disables the seen array until prio_read() uses it too */
-		memset(seen[i], 0xFF, n);
-	}
-
-	ret = btree_root(check_recurse, c, &op, seen);
-err:
-	for (i = 0; i < MAX_CACHES_PER_SET; i++)
-		kfree(seen[i]);
-	return ret;
+	return btree_root(check_recurse, c, &op);
 }
 
 /* Btree insertion */

drivers/md/bcache/btree.h

@@ -251,7 +251,7 @@ int bch_gc_thread_start(struct cache_set *);
 size_t bch_btree_gc_finish(struct cache_set *);
 void bch_moving_gc(struct cache_set *);
 int bch_btree_check(struct cache_set *);
-uint8_t __bch_btree_mark_key(struct cache_set *, int, struct bkey *);
+void bch_initial_mark_key(struct cache_set *, int, struct bkey *);
 
 static inline void wake_up_gc(struct cache_set *c)
 {

drivers/md/bcache/journal.c

@@ -293,21 +293,12 @@ void bch_journal_mark(struct cache_set *c, struct list_head *list)
 		     k < bset_bkey_last(&i->j);
 		     k = bkey_next(k)) {
 			unsigned j;
-			struct bucket *g;
 
-			for (j = 0; j < KEY_PTRS(k); j++) {
-				if (!ptr_available(c, k, j))
-					continue;
+			for (j = 0; j < KEY_PTRS(k); j++)
+				if (ptr_available(c, k, j))
+					atomic_inc(&PTR_BUCKET(c, k, j)->pin);
 
-				g = PTR_BUCKET(c, k, j);
-				atomic_inc(&g->pin);
-
-				if (g->prio == BTREE_PRIO &&
-				    !ptr_stale(c, k, j))
-					g->prio = INITIAL_PRIO;
-			}
-
-			__bch_btree_mark_key(c, 0, k);
+			bch_initial_mark_key(c, 0, k);
 		}
 	}
 }