1 files changed, 133 insertions, 92 deletions

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index beb3255..be90596 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -117,7 +117,7 @@
 ({									\
 	int _r, l = (b)->level - 1;					\
 	bool _w = l <= (op)->lock;					\
-	struct btree *_child = bch_btree_node_get((b)->c, key, l, _w);	\
+	struct btree *_child = bch_btree_node_get((b)->c, op, key, l, _w);\
 	if (!IS_ERR(_child)) {						\
 		_child->parent = (b);					\
 		_r = bch_btree_ ## fn(_child, op, ##__VA_ARGS__);	\
@@ -146,17 +146,12 @@
 			_r = bch_btree_ ## fn(_b, op, ##__VA_ARGS__);	\
 		}							\
 		rw_unlock(_w, _b);					\
+		bch_cannibalize_unlock(c);				\
 		if (_r == -EINTR)					\
 			schedule();					\
-		bch_cannibalize_unlock(c);				\
-		if (_r == -ENOSPC) {					\
-			wait_event((c)->try_wait,			\
-				   !(c)->try_harder);			\
-			_r = -EINTR;					\
-		}							\
 	} while (_r == -EINTR);						\
 									\
-	finish_wait(&(c)->bucket_wait, &(op)->wait);			\
+	finish_wait(&(c)->btree_cache_wait, &(op)->wait);		\
 	_r;								\
 })
 
@@ -563,7 +558,7 @@ static void bch_btree_leaf_dirty(struct btree *b, atomic_t *journal_ref)
 #define mca_reserve(c)	(((c->root && c->root->level)		\
 			  ? c->root->level : 1) * 8 + 16)
 #define mca_can_free(c)						\
-	max_t(int, 0, c->bucket_cache_used - mca_reserve(c))
+	max_t(int, 0, c->btree_cache_used - mca_reserve(c))
 
 static void mca_data_free(struct btree *b)
 {
@@ -571,7 +566,7 @@ static void mca_data_free(struct btree *b)
 
 	bch_btree_keys_free(&b->keys);
 
-	b->c->bucket_cache_used--;
+	b->c->btree_cache_used--;
 	list_move(&b->list, &b->c->btree_cache_freed);
 }
 
@@ -596,7 +591,7 @@ static void mca_data_alloc(struct btree *b, struct bkey *k, gfp_t gfp)
 					ilog2(b->c->btree_pages),
 					btree_order(k)),
 				  gfp)) {
-		b->c->bucket_cache_used++;
+		b->c->btree_cache_used++;
 		list_move(&b->list, &b->c->btree_cache);
 	} else {
 		list_move(&b->list, &b->c->btree_cache_freed);
@@ -675,7 +670,7 @@ static unsigned long bch_mca_scan(struct shrinker *shrink,
 	if (c->shrinker_disabled)
 		return SHRINK_STOP;
 
-	if (c->try_harder)
+	if (c->btree_cache_alloc_lock)
 		return SHRINK_STOP;
 
 	/* Return -1 if we can't do anything right now */
@@ -707,7 +702,7 @@ static unsigned long bch_mca_scan(struct shrinker *shrink,
 		}
 	}
 
-	for (i = 0; (nr--) && i < c->bucket_cache_used; i++) {
+	for (i = 0; (nr--) && i < c->btree_cache_used; i++) {
 		if (list_empty(&c->btree_cache))
 			goto out;
 
@@ -736,7 +731,7 @@ static unsigned long bch_mca_count(struct shrinker *shrink,
 	if (c->shrinker_disabled)
 		return 0;
 
-	if (c->try_harder)
+	if (c->btree_cache_alloc_lock)
 		return 0;
 
 	return mca_can_free(c) * c->btree_pages;
@@ -840,17 +835,30 @@ out:
 	return b;
 }
 
-static struct btree *mca_cannibalize(struct cache_set *c, struct bkey *k)
+static int mca_cannibalize_lock(struct cache_set *c, struct btree_op *op)
+{
+	struct task_struct *old;
+
+	old = cmpxchg(&c->btree_cache_alloc_lock, NULL, current);
+	if (old && old != current) {
+		if (op)
+			prepare_to_wait(&c->btree_cache_wait, &op->wait,
+					TASK_UNINTERRUPTIBLE);
+		return -EINTR;
+	}
+
+	return 0;
+}
+
+static struct btree *mca_cannibalize(struct cache_set *c, struct btree_op *op,
+				     struct bkey *k)
 {
 	struct btree *b;
 
 	trace_bcache_btree_cache_cannibalize(c);
 
-	if (!c->try_harder) {
-		c->try_harder = current;
-		c->try_harder_start = local_clock();
-	} else if (c->try_harder != current)
-		return ERR_PTR(-ENOSPC);
+	if (mca_cannibalize_lock(c, op))
+		return ERR_PTR(-EINTR);
 
 	list_for_each_entry_reverse(b, &c->btree_cache, list)
 		if (!mca_reap(b, btree_order(k), false))
@@ -860,6 +868,7 @@ static struct btree *mca_cannibalize(struct cache_set *c, struct bkey *k)
 		if (!mca_reap(b, btree_order(k), true))
 			return b;
 
+	WARN(1, "btree cache cannibalize failed\n");
 	return ERR_PTR(-ENOMEM);
 }
 
@@ -871,14 +880,14 @@ static struct btree *mca_cannibalize(struct cache_set *c, struct bkey *k)
  */
 static void bch_cannibalize_unlock(struct cache_set *c)
 {
-	if (c->try_harder == current) {
-		bch_time_stats_update(&c->try_harder_time, c->try_harder_start);
-		c->try_harder = NULL;
-		wake_up(&c->try_wait);
+	if (c->btree_cache_alloc_lock == current) {
+		c->btree_cache_alloc_lock = NULL;
+		wake_up(&c->btree_cache_wait);
 	}
 }
 
-static struct btree *mca_alloc(struct cache_set *c, struct bkey *k, int level)
+static struct btree *mca_alloc(struct cache_set *c, struct btree_op *op,
+			       struct bkey *k, int level)
 {
 	struct btree *b;
 
@@ -941,7 +950,7 @@ err:
 	if (b)
 		rw_unlock(true, b);
 
-	b = mca_cannibalize(c, k);
+	b = mca_cannibalize(c, op, k);
 	if (!IS_ERR(b))
 		goto out;
 
@@ -957,8 +966,8 @@ err:
  * The btree node will have either a read or a write lock held, depending on
  * level and op->lock.
  */
-struct btree *bch_btree_node_get(struct cache_set *c, struct bkey *k,
-				 int level, bool write)
+struct btree *bch_btree_node_get(struct cache_set *c, struct btree_op *op,
+				 struct bkey *k, int level, bool write)
 {
 	int i = 0;
 	struct btree *b;
@@ -972,7 +981,7 @@ retry:
 			return ERR_PTR(-EAGAIN);
 
 		mutex_lock(&c->bucket_lock);
-		b = mca_alloc(c, k, level);
+		b = mca_alloc(c, op, k, level);
 		mutex_unlock(&c->bucket_lock);
 
 		if (!b)
@@ -1018,7 +1027,7 @@ static void btree_node_prefetch(struct cache_set *c, struct bkey *k, int level)
 	struct btree *b;
 
 	mutex_lock(&c->bucket_lock);
-	b = mca_alloc(c, k, level);
+	b = mca_alloc(c, NULL, k, level);
 	mutex_unlock(&c->bucket_lock);
 
 	if (!IS_ERR_OR_NULL(b)) {
@@ -1051,20 +1060,21 @@ static void btree_node_free(struct btree *b)
 	mutex_unlock(&b->c->bucket_lock);
 }
 
-struct btree *bch_btree_node_alloc(struct cache_set *c, int level, bool wait)
+struct btree *bch_btree_node_alloc(struct cache_set *c, struct btree_op *op,
+				   int level)
 {
 	BKEY_PADDED(key) k;
 	struct btree *b = ERR_PTR(-EAGAIN);
 
 	mutex_lock(&c->bucket_lock);
 retry:
-	if (__bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, wait))
+	if (__bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, 1, op != NULL))
 		goto err;
 
 	bkey_put(c, &k.key);
 	SET_KEY_SIZE(&k.key, c->btree_pages * PAGE_SECTORS);
 
-	b = mca_alloc(c, &k.key, level);
+	b = mca_alloc(c, op, &k.key, level);
 	if (IS_ERR(b))
 		goto err_free;
 
@@ -1090,9 +1100,10 @@ err:
 	return b;
 }
 
-static struct btree *btree_node_alloc_replacement(struct btree *b, bool wait)
+static struct btree *btree_node_alloc_replacement(struct btree *b,
+						  struct btree_op *op)
 {
-	struct btree *n = bch_btree_node_alloc(b->c, b->level, wait);
+	struct btree *n = bch_btree_node_alloc(b->c, op, b->level);
 	if (!IS_ERR_OR_NULL(n)) {
 		mutex_lock(&n->write_lock);
 		bch_btree_sort_into(&b->keys, &n->keys, &b->c->sort);
@@ -1126,22 +1137,22 @@ static int btree_check_reserve(struct btree *b, struct btree_op *op)
 {
 	struct cache_set *c = b->c;
 	struct cache *ca;
-	unsigned i, reserve = c->root->level * 2 + 1;
-	int ret = 0;
+	unsigned i, reserve = (c->root->level - b->level) * 2 + 1;
 
 	mutex_lock(&c->bucket_lock);
 
 	for_each_cache(ca, c, i)
 		if (fifo_used(&ca->free[RESERVE_BTREE]) < reserve) {
 			if (op)
-				prepare_to_wait(&c->bucket_wait, &op->wait,
+				prepare_to_wait(&c->btree_cache_wait, &op->wait,
 						TASK_UNINTERRUPTIBLE);
-			ret = -EINTR;
-			break;
+			mutex_unlock(&c->bucket_lock);
+			return -EINTR;
 		}
 
 	mutex_unlock(&c->bucket_lock);
-	return ret;
+
+	return mca_cannibalize_lock(b->c, op);
 }
 
 /* Garbage collection */
@@ -1273,14 +1284,19 @@ static int bch_btree_insert_node(struct btree *, struct btree_op *,
 				 struct keylist *, atomic_t *, struct bkey *);
 
 static int btree_gc_coalesce(struct btree *b, struct btree_op *op,
-			     struct keylist *keylist, struct gc_stat *gc,
-			     struct gc_merge_info *r)
+			     struct gc_stat *gc, struct gc_merge_info *r)
 {
 	unsigned i, nodes = 0, keys = 0, blocks;
 	struct btree *new_nodes[GC_MERGE_NODES];
+	struct keylist keylist;
 	struct closure cl;
 	struct bkey *k;
 
+	bch_keylist_init(&keylist);
+
+	if (btree_check_reserve(b, NULL))
+		return 0;
+
 	memset(new_nodes, 0, sizeof(new_nodes));
 	closure_init_stack(&cl);
 
@@ -1295,11 +1311,20 @@ static int btree_gc_coalesce(struct btree *b, struct btree_op *op,
 		return 0;
 
 	for (i = 0; i < nodes; i++) {
-		new_nodes[i] = btree_node_alloc_replacement(r[i].b, false);
+		new_nodes[i] = btree_node_alloc_replacement(r[i].b, NULL);
 		if (IS_ERR_OR_NULL(new_nodes[i]))
 			goto out_nocoalesce;
 	}
 
+	/*
+	 * We have to check the reserve here, after we've allocated our new
+	 * nodes, to make sure the insert below will succeed - we also check
+	 * before as an optimization to potentially avoid a bunch of expensive
+	 * allocs/sorts
+	 */
+	if (btree_check_reserve(b, NULL))
+		goto out_nocoalesce;
+
 	for (i = 0; i < nodes; i++)
 		mutex_lock(&new_nodes[i]->write_lock);
 
@@ -1361,12 +1386,12 @@ static int btree_gc_coalesce(struct btree *b, struct btree_op *op,
 
 		n2->keys -= keys;
 
-		if (__bch_keylist_realloc(keylist,
+		if (__bch_keylist_realloc(&keylist,
 					  bkey_u64s(&new_nodes[i]->key)))
 			goto out_nocoalesce;
 
 		bch_btree_node_write(new_nodes[i], &cl);
-		bch_keylist_add(keylist, &new_nodes[i]->key);
+		bch_keylist_add(&keylist, &new_nodes[i]->key);
 	}
 
 	for (i = 0; i < nodes; i++)
@@ -1380,15 +1405,15 @@ static int btree_gc_coalesce(struct btree *b, struct btree_op *op,
 	rw_unlock(true, new_nodes[0]);
 
 	for (i = 0; i < nodes; i++) {
-		if (__bch_keylist_realloc(keylist, bkey_u64s(&r[i].b->key)))
+		if (__bch_keylist_realloc(&keylist, bkey_u64s(&r[i].b->key)))
 			goto out_nocoalesce;
 
-		make_btree_freeing_key(r[i].b, keylist->top);
-		bch_keylist_push(keylist);
+		make_btree_freeing_key(r[i].b, keylist.top);
+		bch_keylist_push(&keylist);
 	}
 
-	bch_btree_insert_node(b, op, keylist, NULL, NULL);
-	BUG_ON(!bch_keylist_empty(keylist));
+	bch_btree_insert_node(b, op, &keylist, NULL, NULL);
+	BUG_ON(!bch_keylist_empty(&keylist));
 
 	for (i = 0; i < nodes; i++) {
 		btree_node_free(r[i].b);
@@ -1403,13 +1428,16 @@ static int btree_gc_coalesce(struct btree *b, struct btree_op *op,
 	trace_bcache_btree_gc_coalesce(nodes);
 	gc->nodes--;
 
+	bch_keylist_free(&keylist);
+
 	/* Invalidated our iterator */
 	return -EINTR;
 
 out_nocoalesce:
 	closure_sync(&cl);
+	bch_keylist_free(&keylist);
 
-	while ((k = bch_keylist_pop(keylist)))
+	while ((k = bch_keylist_pop(&keylist)))
 		if (!bkey_cmp(k, &ZERO_KEY))
 			atomic_dec(&b->c->prio_blocked);
 
@@ -1421,6 +1449,42 @@ out_nocoalesce:
 	return 0;
 }
 
+static int btree_gc_rewrite_node(struct btree *b, struct btree_op *op,
+				 struct btree *replace)
+{
+	struct keylist keys;
+	struct btree *n;
+
+	if (btree_check_reserve(b, NULL))
+		return 0;
+
+	n = btree_node_alloc_replacement(replace, NULL);
+
+	/* recheck reserve after allocating replacement node */
+	if (btree_check_reserve(b, NULL)) {
+		btree_node_free(n);
+		rw_unlock(true, n);
+		return 0;
+	}
+
+	bch_btree_node_write_sync(n);
+
+	bch_keylist_init(&keys);
+	bch_keylist_add(&keys, &n->key);
+
+	make_btree_freeing_key(replace, keys.top);
+	bch_keylist_push(&keys);
+
+	bch_btree_insert_node(b, op, &keys, NULL, NULL);
+	BUG_ON(!bch_keylist_empty(&keys));
+
+	btree_node_free(replace);
+	rw_unlock(true, n);
+
+	/* Invalidated our iterator */
+	return -EINTR;
+}
+
 static unsigned btree_gc_count_keys(struct btree *b)
 {
 	struct bkey *k;
@@ -1438,14 +1502,11 @@ static int btree_gc_recurse(struct btree *b, struct btree_op *op,
 {
 	int ret = 0;
 	bool should_rewrite;
-	struct btree *n;
 	struct bkey *k;
-	struct keylist keys;
 	struct btree_iter iter;
 	struct gc_merge_info r[GC_MERGE_NODES];
 	struct gc_merge_info *i, *last = r + ARRAY_SIZE(r) - 1;
 
-	bch_keylist_init(&keys);
 	bch_btree_iter_init(&b->keys, &iter, &b->c->gc_done);
 
 	for (i = r; i < r + ARRAY_SIZE(r); i++)
@@ -1454,7 +1515,8 @@ static int btree_gc_recurse(struct btree *b, struct btree_op *op,
 	while (1) {
 		k = bch_btree_iter_next_filter(&iter, &b->keys, bch_ptr_bad);
 		if (k) {
-			r->b = bch_btree_node_get(b->c, k, b->level - 1, true);
+			r->b = bch_btree_node_get(b->c, op, k, b->level - 1,
+						  true);
 			if (IS_ERR(r->b)) {
 				ret = PTR_ERR(r->b);
 				break;
@@ -1462,7 +1524,7 @@ static int btree_gc_recurse(struct btree *b, struct btree_op *op,
 
 			r->keys = btree_gc_count_keys(r->b);
 
-			ret = btree_gc_coalesce(b, op, &keys, gc, r);
+			ret = btree_gc_coalesce(b, op, gc, r);
 			if (ret)
 				break;
 		}
@@ -1472,32 +1534,10 @@ static int btree_gc_recurse(struct btree *b, struct btree_op *op,
 
 		if (!IS_ERR(last->b)) {
 			should_rewrite = btree_gc_mark_node(last->b, gc);
-			if (should_rewrite &&
-			    !btree_check_reserve(b, NULL)) {
-				n = btree_node_alloc_replacement(last->b,
-								 false);
-
-				if (!IS_ERR_OR_NULL(n)) {
-					bch_btree_node_write_sync(n);
-
-					bch_keylist_add(&keys, &n->key);
-
-					make_btree_freeing_key(last->b,
-							       keys.top);
-					bch_keylist_push(&keys);
-
-					bch_btree_insert_node(b, op, &keys,
-							      NULL, NULL);
-					BUG_ON(!bch_keylist_empty(&keys));
-
-					btree_node_free(last->b);
-					rw_unlock(true, last->b);
-					last->b = n;
-
-					/* Invalidated our iterator */
-					ret = -EINTR;
+			if (should_rewrite) {
+				ret = btree_gc_rewrite_node(b, op, last->b);
+				if (ret)
 					break;
-				}
 			}
 
 			if (last->b->level) {
@@ -1537,8 +1577,6 @@ static int btree_gc_recurse(struct btree *b, struct btree_op *op,
 			rw_unlock(true, i->b);
 		}
 
-	bch_keylist_free(&keys);
-
 	return ret;
 }
 
@@ -1551,7 +1589,7 @@ static int bch_btree_gc_root(struct btree *b, struct btree_op *op,
 
 	should_rewrite = btree_gc_mark_node(b, gc);
 	if (should_rewrite) {
-		n = btree_node_alloc_replacement(b, false);
+		n = btree_node_alloc_replacement(b, NULL);
 
 		if (!IS_ERR_OR_NULL(n)) {
 			bch_btree_node_write_sync(n);
@@ -1887,11 +1925,14 @@ static int btree_split(struct btree *b, struct btree_op *op,
 	closure_init_stack(&cl);
 	bch_keylist_init(&parent_keys);
 
-	if (!b->level &&
-	    btree_check_reserve(b, op))
-		return -EINTR;
+	if (btree_check_reserve(b, op)) {
+		if (!b->level)
+			return -EINTR;
+		else
+			WARN(1, "insufficient reserve for split\n");
+	}
 
-	n1 = btree_node_alloc_replacement(b, true);
+	n1 = btree_node_alloc_replacement(b, op);
 	if (IS_ERR(n1))
 		goto err;
 
@@ -1903,12 +1944,12 @@ static int btree_split(struct btree *b, struct btree_op *op,
 
 		trace_bcache_btree_node_split(b, btree_bset_first(n1)->keys);
 
-		n2 = bch_btree_node_alloc(b->c, b->level, true);
+		n2 = bch_btree_node_alloc(b->c, op, b->level);
 		if (IS_ERR(n2))
 			goto err_free1;
 
 		if (!b->parent) {
-			n3 = bch_btree_node_alloc(b->c, b->level + 1, true);
+			n3 = bch_btree_node_alloc(b->c, op, b->level + 1);
 			if (IS_ERR(n3))
 				goto err_free2;
 		}
@@ -1995,7 +2036,7 @@ err_free1:
 	btree_node_free(n1);
 	rw_unlock(true, n1);
 err:
-	WARN(1, "bcache: btree split failed");
+	WARN(1, "bcache: btree split failed (level %u)", b->level);
 
 	if (n3 == ERR_PTR(-EAGAIN) ||
 	    n2 == ERR_PTR(-EAGAIN) ||