1 files changed, 515 insertions, 389 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 42491d728e99..e5b2533b691a 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -254,18 +254,13 @@ int btrfs_copy_root(struct btrfs_trans_handle *trans,
  * empty_size -- a hint that you plan on doing more cow.  This is the size in
  * bytes the allocator should try to find free next to the block it returns.
  * This is just a hint and may be ignored by the allocator.
- *
- * prealloc_dest -- if you have already reserved a destination for the cow,
- * this uses that block instead of allocating a new one.
- * btrfs_alloc_reserved_extent is used to finish the allocation.
  */
 static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 			     struct btrfs_root *root,
 			     struct extent_buffer *buf,
 			     struct extent_buffer *parent, int parent_slot,
 			     struct extent_buffer **cow_ret,
-			     u64 search_start, u64 empty_size,
-			     u64 prealloc_dest)
+			     u64 search_start, u64 empty_size)
 {
 	u64 parent_start;
 	struct extent_buffer *cow;
@@ -277,7 +272,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 	if (*cow_ret == buf)
 		unlock_orig = 1;
 
-	WARN_ON(!btrfs_tree_locked(buf));
+	btrfs_assert_tree_locked(buf);
 
 	if (parent)
 		parent_start = parent->start;
@@ -291,26 +286,10 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 	level = btrfs_header_level(buf);
 	nritems = btrfs_header_nritems(buf);
 
-	if (prealloc_dest) {
-		struct btrfs_key ins;
-
-		ins.objectid = prealloc_dest;
-		ins.offset = buf->len;
-		ins.type = BTRFS_EXTENT_ITEM_KEY;
-
-		ret = btrfs_alloc_reserved_extent(trans, root, parent_start,
-						  root->root_key.objectid,
-						  trans->transid, level, &ins);
-		BUG_ON(ret);
-		cow = btrfs_init_new_buffer(trans, root, prealloc_dest,
-					    buf->len, level);
-	} else {
-		cow = btrfs_alloc_free_block(trans, root, buf->len,
-					     parent_start,
-					     root->root_key.objectid,
-					     trans->transid, level,
-					     search_start, empty_size);
-	}
+	cow = btrfs_alloc_free_block(trans, root, buf->len,
+				     parent_start, root->root_key.objectid,
+				     trans->transid, level,
+				     search_start, empty_size);
 	if (IS_ERR(cow))
 		return PTR_ERR(cow);
 
@@ -413,7 +392,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
 		    struct btrfs_root *root, struct extent_buffer *buf,
 		    struct extent_buffer *parent, int parent_slot,
-		    struct extent_buffer **cow_ret, u64 prealloc_dest)
+		    struct extent_buffer **cow_ret)
 {
 	u64 search_start;
 	int ret;
@@ -436,7 +415,6 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
 	    btrfs_header_owner(buf) == root->root_key.objectid &&
 	    !btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
 		*cow_ret = buf;
-		WARN_ON(prealloc_dest);
 		return 0;
 	}
 
@@ -447,8 +425,7 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans,
 	btrfs_set_lock_blocking(buf);
 
 	ret = __btrfs_cow_block(trans, root, buf, parent,
-				 parent_slot, cow_ret, search_start, 0,
-				 prealloc_dest);
+				 parent_slot, cow_ret, search_start, 0);
 	return ret;
 }
 
@@ -617,7 +594,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 		err = __btrfs_cow_block(trans, root, cur, parent, i,
 					&cur, search_start,
 					min(16 * blocksize,
-					    (end_slot - i) * blocksize), 0);
+					    (end_slot - i) * blocksize));
 		if (err) {
 			btrfs_tree_unlock(cur);
 			free_extent_buffer(cur);
@@ -937,7 +914,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 		BUG_ON(!child);
 		btrfs_tree_lock(child);
 		btrfs_set_lock_blocking(child);
-		ret = btrfs_cow_block(trans, root, child, mid, 0, &child, 0);
+		ret = btrfs_cow_block(trans, root, child, mid, 0, &child);
 		BUG_ON(ret);
 
 		spin_lock(&root->node_lock);
@@ -945,6 +922,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 		spin_unlock(&root->node_lock);
 
 		ret = btrfs_update_extent_ref(trans, root, child->start,
+					      child->len,
 					      mid->start, child->start,
 					      root->root_key.objectid,
 					      trans->transid, level - 1);
@@ -971,6 +949,10 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 	    BTRFS_NODEPTRS_PER_BLOCK(root) / 4)
 		return 0;
 
+	if (trans->transaction->delayed_refs.flushing &&
+	    btrfs_header_nritems(mid) > 2)
+		return 0;
+
 	if (btrfs_header_nritems(mid) < 2)
 		err_on_enospc = 1;
 
@@ -979,7 +961,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 		btrfs_tree_lock(left);
 		btrfs_set_lock_blocking(left);
 		wret = btrfs_cow_block(trans, root, left,
-				       parent, pslot - 1, &left, 0);
+				       parent, pslot - 1, &left);
 		if (wret) {
 			ret = wret;
 			goto enospc;
@@ -990,7 +972,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 		btrfs_tree_lock(right);
 		btrfs_set_lock_blocking(right);
 		wret = btrfs_cow_block(trans, root, right,
-				       parent, pslot + 1, &right, 0);
+				       parent, pslot + 1, &right);
 		if (wret) {
 			ret = wret;
 			goto enospc;
@@ -1171,7 +1153,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
 			wret = 1;
 		} else {
 			ret = btrfs_cow_block(trans, root, left, parent,
-					      pslot - 1, &left, 0);
+					      pslot - 1, &left);
 			if (ret)
 				wret = 1;
 			else {
@@ -1222,7 +1204,7 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
 		} else {
 			ret = btrfs_cow_block(trans, root, right,
 					      parent, pslot + 1,
-					      &right, 0);
+					      &right);
 			if (ret)
 				wret = 1;
 			else {
@@ -1262,9 +1244,9 @@ static noinline int push_nodes_for_insert(struct btrfs_trans_handle *trans,
  * readahead one full node of leaves, finding things that are close
  * to the block in 'slot', and triggering ra on them.
  */
-static noinline void reada_for_search(struct btrfs_root *root,
-				      struct btrfs_path *path,
-				      int level, int slot, u64 objectid)
+static void reada_for_search(struct btrfs_root *root,
+			     struct btrfs_path *path,
+			     int level, int slot, u64 objectid)
 {
 	struct extent_buffer *node;
 	struct btrfs_disk_key disk_key;
@@ -1465,6 +1447,117 @@ noinline void btrfs_unlock_up_safe(struct btrfs_path *path, int level)
 }
 
 /*
+ * helper function for btrfs_search_slot.  The goal is to find a block
+ * in cache without setting the path to blocking.  If we find the block
+ * we return zero and the path is unchanged.
+ *
+ * If we can't find the block, we set the path blocking and do some
+ * reada.  -EAGAIN is returned and the search must be repeated.
+ */
+static int
+read_block_for_search(struct btrfs_trans_handle *trans,
+		       struct btrfs_root *root, struct btrfs_path *p,
+		       struct extent_buffer **eb_ret, int level, int slot,
+		       struct btrfs_key *key)
+{
+	u64 blocknr;
+	u64 gen;
+	u32 blocksize;
+	struct extent_buffer *b = *eb_ret;
+	struct extent_buffer *tmp;
+
+	blocknr = btrfs_node_blockptr(b, slot);
+	gen = btrfs_node_ptr_generation(b, slot);
+	blocksize = btrfs_level_size(root, level - 1);
+
+	tmp = btrfs_find_tree_block(root, blocknr, blocksize);
+	if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
+		*eb_ret = tmp;
+		return 0;
+	}
+
+	/*
+	 * reduce lock contention at high levels
+	 * of the btree by dropping locks before
+	 * we read.
+	 */
+	btrfs_release_path(NULL, p);
+	if (tmp)
+		free_extent_buffer(tmp);
+	if (p->reada)
+		reada_for_search(root, p, level, slot, key->objectid);
+
+	tmp = read_tree_block(root, blocknr, blocksize, gen);
+	if (tmp)
+		free_extent_buffer(tmp);
+	return -EAGAIN;
+}
+
+/*
+ * helper function for btrfs_search_slot.  This does all of the checks
+ * for node-level blocks and does any balancing required based on
+ * the ins_len.
+ *
+ * If no extra work was required, zero is returned.  If we had to
+ * drop the path, -EAGAIN is returned and btrfs_search_slot must
+ * start over
+ */
+static int
+setup_nodes_for_search(struct btrfs_trans_handle *trans,
+		       struct btrfs_root *root, struct btrfs_path *p,
+		       struct extent_buffer *b, int level, int ins_len)
+{
+	int ret;
+	if ((p->search_for_split || ins_len > 0) && btrfs_header_nritems(b) >=
+	    BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
+		int sret;
+
+		sret = reada_for_balance(root, p, level);
+		if (sret)
+			goto again;
+
+		btrfs_set_path_blocking(p);
+		sret = split_node(trans, root, p, level);
+		btrfs_clear_path_blocking(p, NULL);
+
+		BUG_ON(sret > 0);
+		if (sret) {
+			ret = sret;
+			goto done;
+		}
+		b = p->nodes[level];
+	} else if (ins_len < 0 && btrfs_header_nritems(b) <
+		   BTRFS_NODEPTRS_PER_BLOCK(root) / 4) {
+		int sret;
+
+		sret = reada_for_balance(root, p, level);
+		if (sret)
+			goto again;
+
+		btrfs_set_path_blocking(p);
+		sret = balance_level(trans, root, p, level);
+		btrfs_clear_path_blocking(p, NULL);
+
+		if (sret) {
+			ret = sret;
+			goto done;
+		}
+		b = p->nodes[level];
+		if (!b) {
+			btrfs_release_path(NULL, p);
+			goto again;
+		}
+		BUG_ON(btrfs_header_nritems(b) == 1);
+	}
+	return 0;
+
+again:
+	ret = -EAGAIN;
+done:
+	return ret;
+}
+
+/*
  * look for key in the tree.  path is filled in with nodes along the way
  * if key is found, we return zero and you can find the item in the leaf
  * level of the path (level 0)
@@ -1482,17 +1575,11 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
 		      ins_len, int cow)
 {
 	struct extent_buffer *b;
-	struct extent_buffer *tmp;
 	int slot;
 	int ret;
 	int level;
-	int should_reada = p->reada;
 	int lowest_unlock = 1;
-	int blocksize;
 	u8 lowest_level = 0;
-	u64 blocknr;
-	u64 gen;
-	struct btrfs_key prealloc_block;
 
 	lowest_level = p->lowest_level;
 	WARN_ON(lowest_level && ins_len > 0);
@@ -1501,8 +1588,6 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
 	if (ins_len < 0)
 		lowest_unlock = 2;
 
-	prealloc_block.objectid = 0;
-
 again:
 	if (p->skip_locking)
 		b = btrfs_root_node(root);
@@ -1523,50 +1608,21 @@ again:
 		if (cow) {
 			int wret;
 
-			/* is a cow on this block not required */
+			/*
+			 * if we don't really need to cow this block
+			 * then we don't want to set the path blocking,
+			 * so we test it here
+			 */
 			if (btrfs_header_generation(b) == trans->transid &&
 			    btrfs_header_owner(b) == root->root_key.objectid &&
 			    !btrfs_header_flag(b, BTRFS_HEADER_FLAG_WRITTEN)) {
 				goto cow_done;
 			}
-
-			/* ok, we have to cow, is our old prealloc the right
-			 * size?
-			 */
-			if (prealloc_block.objectid &&
-			    prealloc_block.offset != b->len) {
-				btrfs_release_path(root, p);
-				btrfs_free_reserved_extent(root,
-					   prealloc_block.objectid,
-					   prealloc_block.offset);
-				prealloc_block.objectid = 0;
-				goto again;
-			}
-
-			/*
-			 * for higher level blocks, try not to allocate blocks
-			 * with the block and the parent locks held.
-			 */
-			if (level > 0 && !prealloc_block.objectid) {
-				u32 size = b->len;
-				u64 hint = b->start;
-
-				btrfs_release_path(root, p);
-				ret = btrfs_reserve_extent(trans, root,
-							   size, size, 0,
-							   hint, (u64)-1,
-							   &prealloc_block, 0);
-				BUG_ON(ret);
-				goto again;
-			}
-
 			btrfs_set_path_blocking(p);
 
 			wret = btrfs_cow_block(trans, root, b,
 					       p->nodes[level + 1],
-					       p->slots[level + 1],
-					       &b, prealloc_block.objectid);
-			prealloc_block.objectid = 0;
+					       p->slots[level + 1], &b);
 			if (wret) {
 				free_extent_buffer(b);
 				ret = wret;
@@ -1611,51 +1667,15 @@ cow_done:
 			if (ret && slot > 0)
 				slot -= 1;
 			p->slots[level] = slot;
-			if ((p->search_for_split || ins_len > 0) &&
-			    btrfs_header_nritems(b) >=
-			    BTRFS_NODEPTRS_PER_BLOCK(root) - 3) {
-				int sret;
-
-				sret = reada_for_balance(root, p, level);
-				if (sret)
-					goto again;
-
-				btrfs_set_path_blocking(p);
-				sret = split_node(trans, root, p, level);
-				btrfs_clear_path_blocking(p, NULL);
-
-				BUG_ON(sret > 0);
-				if (sret) {
-					ret = sret;
-					goto done;
-				}
-				b = p->nodes[level];
-				slot = p->slots[level];
-			} else if (ins_len < 0 &&
-				   btrfs_header_nritems(b) <
-				   BTRFS_NODEPTRS_PER_BLOCK(root) / 4) {
-				int sret;
-
-				sret = reada_for_balance(root, p, level);
-				if (sret)
-					goto again;
-
-				btrfs_set_path_blocking(p);
-				sret = balance_level(trans, root, p, level);
-				btrfs_clear_path_blocking(p, NULL);
+			ret = setup_nodes_for_search(trans, root, p, b, level,
+						     ins_len);
+			if (ret == -EAGAIN)
+				goto again;
+			else if (ret)
+				goto done;
+			b = p->nodes[level];
+			slot = p->slots[level];
 
-				if (sret) {
-					ret = sret;
-					goto done;
-				}
-				b = p->nodes[level];
-				if (!b) {
-					btrfs_release_path(NULL, p);
-					goto again;
-				}
-				slot = p->slots[level];
-				BUG_ON(btrfs_header_nritems(b) == 1);
-			}
 			unlock_up(p, level, lowest_unlock);
 
 			/* this is only true while dropping a snapshot */
@@ -1664,44 +1684,11 @@ cow_done:
 				goto done;
 			}
 
-			blocknr = btrfs_node_blockptr(b, slot);
-			gen = btrfs_node_ptr_generation(b, slot);
-			blocksize = btrfs_level_size(root, level - 1);
+			ret = read_block_for_search(trans, root, p,
+						    &b, level, slot, key);
+			if (ret == -EAGAIN)
+				goto again;
 
-			tmp = btrfs_find_tree_block(root, blocknr, blocksize);
-			if (tmp && btrfs_buffer_uptodate(tmp, gen)) {
-				b = tmp;
-			} else {
-				/*
-				 * reduce lock contention at high levels
-				 * of the btree by dropping locks before
-				 * we read.
-				 */
-				if (level > 0) {
-					btrfs_release_path(NULL, p);
-					if (tmp)
-						free_extent_buffer(tmp);
-					if (should_reada)
-						reada_for_search(root, p,
-								 level, slot,
-								 key->objectid);
-
-					tmp = read_tree_block(root, blocknr,
-							 blocksize, gen);
-					if (tmp)
-						free_extent_buffer(tmp);
-					goto again;
-				} else {
-					btrfs_set_path_blocking(p);
-					if (tmp)
-						free_extent_buffer(tmp);
-					if (should_reada)
-						reada_for_search(root, p,
-								 level, slot,
-								 key->objectid);
-					b = read_node_slot(root, b, slot);
-				}
-			}
 			if (!p->skip_locking) {
 				int lret;
 
@@ -1742,12 +1729,8 @@ done:
 	 * we don't really know what they plan on doing with the path
 	 * from here on, so for now just mark it as blocking
 	 */
-	btrfs_set_path_blocking(p);
-	if (prealloc_block.objectid) {
-		btrfs_free_reserved_extent(root,
-			   prealloc_block.objectid,
-			   prealloc_block.offset);
-	}
+	if (!p->leave_spinning)
+		btrfs_set_path_blocking(p);
 	return ret;
 }
 
@@ -1768,7 +1751,7 @@ int btrfs_merge_path(struct btrfs_trans_handle *trans,
 	int ret;
 
 	eb = btrfs_lock_root_node(root);
-	ret = btrfs_cow_block(trans, root, eb, NULL, 0, &eb, 0);
+	ret = btrfs_cow_block(trans, root, eb, NULL, 0, &eb);
 	BUG_ON(ret);
 
 	btrfs_set_lock_blocking(eb);
@@ -1826,7 +1809,7 @@ int btrfs_merge_path(struct btrfs_trans_handle *trans,
 			}
 
 			ret = btrfs_cow_block(trans, root, eb, parent, slot,
-					      &eb, 0);
+					      &eb);
 			BUG_ON(ret);
 
 			if (root->root_key.objectid ==
@@ -2139,7 +2122,7 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans,
 	spin_unlock(&root->node_lock);
 
 	ret = btrfs_update_extent_ref(trans, root, lower->start,
-				      lower->start, c->start,
+				      lower->len, lower->start, c->start,
 				      root->root_key.objectid,
 				      trans->transid, level - 1);
 	BUG_ON(ret);
@@ -2174,8 +2157,7 @@ static int insert_ptr(struct btrfs_trans_handle *trans, struct btrfs_root
 	BUG_ON(!path->nodes[level]);
 	lower = path->nodes[level];
 	nritems = btrfs_header_nritems(lower);
-	if (slot > nritems)
-		BUG();
+	BUG_ON(slot > nritems);
 	if (nritems == BTRFS_NODEPTRS_PER_BLOCK(root))
 		BUG();
 	if (slot != nritems) {
@@ -2221,7 +2203,7 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
 		ret = insert_new_root(trans, root, path, level + 1);
 		if (ret)
 			return ret;
-	} else {
+	} else if (!trans->transaction->delayed_refs.flushing) {
 		ret = push_nodes_for_insert(trans, root, path, level);
 		c = path->nodes[level];
 		if (!ret && btrfs_header_nritems(c) <
@@ -2329,66 +2311,27 @@ noinline int btrfs_leaf_free_space(struct btrfs_root *root,
 	return ret;
 }
 
-/*
- * push some data in the path leaf to the right, trying to free up at
- * least data_size bytes.  returns zero if the push worked, nonzero otherwise
- *
- * returns 1 if the push failed because the other node didn't have enough
- * room, 0 if everything worked out and < 0 if there were major errors.
- */
-static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
-			   *root, struct btrfs_path *path, int data_size,
-			   int empty)
+static noinline int __push_leaf_right(struct btrfs_trans_handle *trans,
+				      struct btrfs_root *root,
+				      struct btrfs_path *path,
+				      int data_size, int empty,
+				      struct extent_buffer *right,
+				      int free_space, u32 left_nritems)
 {
 	struct extent_buffer *left = path->nodes[0];
-	struct extent_buffer *right;
-	struct extent_buffer *upper;
+	struct extent_buffer *upper = path->nodes[1];
 	struct btrfs_disk_key disk_key;
 	int slot;
 	u32 i;
-	int free_space;
 	int push_space = 0;
 	int push_items = 0;
 	struct btrfs_item *item;
-	u32 left_nritems;
 	u32 nr;
 	u32 right_nritems;
 	u32 data_end;
 	u32 this_item_size;
 	int ret;
 
-	slot = path->slots[1];
-	if (!path->nodes[1])
-		return 1;
-
-	upper = path->nodes[1];
-	if (slot >= btrfs_header_nritems(upper) - 1)
-		return 1;
-
-	WARN_ON(!btrfs_tree_locked(path->nodes[1]));
-
-	right = read_node_slot(root, upper, slot + 1);
-	btrfs_tree_lock(right);
-	btrfs_set_lock_blocking(right);
-
-	free_space = btrfs_leaf_free_space(root, right);
-	if (free_space < data_size)
-		goto out_unlock;
-
-	/* cow and double check */
-	ret = btrfs_cow_block(trans, root, right, upper,
-			      slot + 1, &right, 0);
-	if (ret)
-		goto out_unlock;
-
-	free_space = btrfs_leaf_free_space(root, right);
-	if (free_space < data_size)
-		goto out_unlock;
-
-	left_nritems = btrfs_header_nritems(left);
-	if (left_nritems == 0)
-		goto out_unlock;
-
 	if (empty)
 		nr = 0;
 	else
@@ -2397,6 +2340,7 @@ static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
 	if (path->slots[0] >= left_nritems)
 		push_space += data_size;
 
+	slot = path->slots[1];
 	i = left_nritems - 1;
 	while (i >= nr) {
 		item = btrfs_item_nr(left, i);
@@ -2528,24 +2472,82 @@ out_unlock:
 }
 
 /*
+ * push some data in the path leaf to the right, trying to free up at
+ * least data_size bytes.  returns zero if the push worked, nonzero otherwise
+ *
+ * returns 1 if the push failed because the other node didn't have enough
+ * room, 0 if everything worked out and < 0 if there were major errors.
+ */
+static int push_leaf_right(struct btrfs_trans_handle *trans, struct btrfs_root
+			   *root, struct btrfs_path *path, int data_size,
+			   int empty)
+{
+	struct extent_buffer *left = path->nodes[0];
+	struct extent_buffer *right;
+	struct extent_buffer *upper;
+	int slot;
+	int free_space;
+	u32 left_nritems;
+	int ret;
+
+	if (!path->nodes[1])
+		return 1;
+
+	slot = path->slots[1];
+	upper = path->nodes[1];
+	if (slot >= btrfs_header_nritems(upper) - 1)
+		return 1;
+
+	btrfs_assert_tree_locked(path->nodes[1]);
+
+	right = read_node_slot(root, upper, slot + 1);
+	btrfs_tree_lock(right);
+	btrfs_set_lock_blocking(right);
+
+	free_space = btrfs_leaf_free_space(root, right);
+	if (free_space < data_size)
+		goto out_unlock;
+
+	/* cow and double check */
+	ret = btrfs_cow_block(trans, root, right, upper,
+			      slot + 1, &right);
+	if (ret)
+		goto out_unlock;
+
+	free_space = btrfs_leaf_free_space(root, right);
+	if (free_space < data_size)
+		goto out_unlock;
+
+	left_nritems = btrfs_header_nritems(left);
+	if (left_nritems == 0)
+		goto out_unlock;
+
+	return __push_leaf_right(trans, root, path, data_size, empty,
+				right, free_space, left_nritems);
+out_unlock:
+	btrfs_tree_unlock(right);
+	free_extent_buffer(right);
+	return 1;
+}
+
+/*
  * push some data in the path leaf to the left, trying to free up at
  * least data_size bytes.  returns zero if the push worked, nonzero otherwise
  */
-static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
-			  *root, struct btrfs_path *path, int data_size,
-			  int empty)
+static noinline int __push_leaf_left(struct btrfs_trans_handle *trans,
+				     struct btrfs_root *root,
+				     struct btrfs_path *path, int data_size,
+				     int empty, struct extent_buffer *left,
+				     int free_space, int right_nritems)
 {
 	struct btrfs_disk_key disk_key;
 	struct extent_buffer *right = path->nodes[0];
-	struct extent_buffer *left;
 	int slot;
 	int i;
-	int free_space;
 	int push_space = 0;
 	int push_items = 0;
 	struct btrfs_item *item;
 	u32 old_left_nritems;
-	u32 right_nritems;
 	u32 nr;
 	int ret = 0;
 	int wret;
@@ -2553,41 +2555,6 @@ static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
 	u32 old_left_item_size;
 
 	slot = path->slots[1];
-	if (slot == 0)
-		return 1;
-	if (!path->nodes[1])
-		return 1;
-
-	right_nritems = btrfs_header_nritems(right);
-	if (right_nritems == 0)
-		return 1;
-
-	WARN_ON(!btrfs_tree_locked(path->nodes[1]));
-
-	left = read_node_slot(root, path->nodes[1], slot - 1);
-	btrfs_tree_lock(left);
-	btrfs_set_lock_blocking(left);
-
-	free_space = btrfs_leaf_free_space(root, left);
-	if (free_space < data_size) {
-		ret = 1;
-		goto out;
-	}
-
-	/* cow and double check */
-	ret = btrfs_cow_block(trans, root, left,
-			      path->nodes[1], slot - 1, &left, 0);
-	if (ret) {
-		/* we hit -ENOSPC, but it isn't fatal here */
-		ret = 1;
-		goto out;
-	}
-
-	free_space = btrfs_leaf_free_space(root, left);
-	if (free_space < data_size) {
-		ret = 1;
-		goto out;
-	}
 
 	if (empty)
 		nr = right_nritems;
@@ -2755,6 +2722,154 @@ out:
 }
 
 /*
+ * push some data in the path leaf to the left, trying to free up at
+ * least data_size bytes.  returns zero if the push worked, nonzero otherwise
+ */
+static int push_leaf_left(struct btrfs_trans_handle *trans, struct btrfs_root
+			  *root, struct btrfs_path *path, int data_size,
+			  int empty)
+{
+	struct extent_buffer *right = path->nodes[0];
+	struct extent_buffer *left;
+	int slot;
+	int free_space;
+	u32 right_nritems;
+	int ret = 0;
+
+	slot = path->slots[1];
+	if (slot == 0)
+		return 1;
+	if (!path->nodes[1])
+		return 1;
+
+	right_nritems = btrfs_header_nritems(right);
+	if (right_nritems == 0)
+		return 1;
+
+	btrfs_assert_tree_locked(path->nodes[1]);
+
+	left = read_node_slot(root, path->nodes[1], slot - 1);
+	btrfs_tree_lock(left);
+	btrfs_set_lock_blocking(left);
+
+	free_space = btrfs_leaf_free_space(root, left);
+	if (free_space < data_size) {
+		ret = 1;
+		goto out;
+	}
+
+	/* cow and double check */
+	ret = btrfs_cow_block(trans, root, left,
+			      path->nodes[1], slot - 1, &left);
+	if (ret) {
+		/* we hit -ENOSPC, but it isn't fatal here */
+		ret = 1;
+		goto out;
+	}
+
+	free_space = btrfs_leaf_free_space(root, left);
+	if (free_space < data_size) {
+		ret = 1;
+		goto out;
+	}
+
+	return __push_leaf_left(trans, root, path, data_size,
+			       empty, left, free_space, right_nritems);
+out:
+	btrfs_tree_unlock(left);
+	free_extent_buffer(left);
+	return ret;
+}
+
+/*
+ * split the path's leaf in two, making sure there is at least data_size
+ * available for the resulting leaf level of the path.
+ *
+ * returns 0 if all went well and < 0 on failure.
+ */
+static noinline int copy_for_split(struct btrfs_trans_handle *trans,
+			       struct btrfs_root *root,
+			       struct btrfs_path *path,
+			       struct extent_buffer *l,
+			       struct extent_buffer *right,
+			       int slot, int mid, int nritems)
+{
+	int data_copy_size;
+	int rt_data_off;
+	int i;
+	int ret = 0;
+	int wret;
+	struct btrfs_disk_key disk_key;
+
+	nritems = nritems - mid;
+	btrfs_set_header_nritems(right, nritems);
+	data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
+
+	copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
+			   btrfs_item_nr_offset(mid),
+			   nritems * sizeof(struct btrfs_item));
+
+	copy_extent_buffer(right, l,
+		     btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
+		     data_copy_size, btrfs_leaf_data(l) +
+		     leaf_data_end(root, l), data_copy_size);
+
+	rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
+		      btrfs_item_end_nr(l, mid);
+
+	for (i = 0; i < nritems; i++) {
+		struct btrfs_item *item = btrfs_item_nr(right, i);
+		u32 ioff;
+
+		if (!right->map_token) {
+			map_extent_buffer(right, (unsigned long)item,
+					sizeof(struct btrfs_item),
+					&right->map_token, &right->kaddr,
+					&right->map_start, &right->map_len,
+					KM_USER1);
+		}
+
+		ioff = btrfs_item_offset(right, item);
+		btrfs_set_item_offset(right, item, ioff + rt_data_off);
+	}
+
+	if (right->map_token) {
+		unmap_extent_buffer(right, right->map_token, KM_USER1);
+		right->map_token = NULL;
+	}
+
+	btrfs_set_header_nritems(l, mid);
+	ret = 0;
+	btrfs_item_key(right, &disk_key, 0);
+	wret = insert_ptr(trans, root, path, &disk_key, right->start,
+			  path->slots[1] + 1, 1);
+	if (wret)
+		ret = wret;
+
+	btrfs_mark_buffer_dirty(right);
+	btrfs_mark_buffer_dirty(l);
+	BUG_ON(path->slots[0] != slot);
+
+	ret = btrfs_update_ref(trans, root, l, right, 0, nritems);
+	BUG_ON(ret);
+
+	if (mid <= slot) {
+		btrfs_tree_unlock(path->nodes[0]);
+		free_extent_buffer(path->nodes[0]);
+		path->nodes[0] = right;
+		path->slots[0] -= mid;
+		path->slots[1] += 1;
+	} else {
+		btrfs_tree_unlock(right);
+		free_extent_buffer(right);
+	}
+
+	BUG_ON(path->slots[0] < 0);
+
+	return ret;
+}
+
+/*
  * split the path's leaf in two, making sure there is at least data_size
  * available for the resulting leaf level of the path.
  *
@@ -2771,17 +2886,14 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
 	int mid;
 	int slot;
 	struct extent_buffer *right;
-	int data_copy_size;
-	int rt_data_off;
-	int i;
 	int ret = 0;
 	int wret;
 	int double_split;
 	int num_doubles = 0;
-	struct btrfs_disk_key disk_key;
 
 	/* first try to make some room by pushing left and right */
-	if (data_size && ins_key->type != BTRFS_DIR_ITEM_KEY) {
+	if (data_size && ins_key->type != BTRFS_DIR_ITEM_KEY &&
+	    !trans->transaction->delayed_refs.flushing) {
 		wret = push_leaf_right(trans, root, path, data_size, 0);
 		if (wret < 0)
 			return wret;
@@ -2830,11 +2942,14 @@ again:
 	write_extent_buffer(right, root->fs_info->chunk_tree_uuid,
 			    (unsigned long)btrfs_header_chunk_tree_uuid(right),
 			    BTRFS_UUID_SIZE);
+
 	if (mid <= slot) {
 		if (nritems == 1 ||
 		    leaf_space_used(l, mid, nritems - mid) + data_size >
 			BTRFS_LEAF_DATA_SIZE(root)) {
 			if (slot >= nritems) {
+				struct btrfs_disk_key disk_key;
+
 				btrfs_cpu_key_to_disk(&disk_key, ins_key);
 				btrfs_set_header_nritems(right, 0);
 				wret = insert_ptr(trans, root, path,
@@ -2862,6 +2977,8 @@ again:
 		if (leaf_space_used(l, 0, mid) + data_size >
 			BTRFS_LEAF_DATA_SIZE(root)) {
 			if (!extend && data_size && slot == 0) {
+				struct btrfs_disk_key disk_key;
+
 				btrfs_cpu_key_to_disk(&disk_key, ins_key);
 				btrfs_set_header_nritems(right, 0);
 				wret = insert_ptr(trans, root, path,
@@ -2894,76 +3011,16 @@ again:
 			}
 		}
 	}
-	nritems = nritems - mid;
-	btrfs_set_header_nritems(right, nritems);
-	data_copy_size = btrfs_item_end_nr(l, mid) - leaf_data_end(root, l);
-
-	copy_extent_buffer(right, l, btrfs_item_nr_offset(0),
-			   btrfs_item_nr_offset(mid),
-			   nritems * sizeof(struct btrfs_item));
-
-	copy_extent_buffer(right, l,
-		     btrfs_leaf_data(right) + BTRFS_LEAF_DATA_SIZE(root) -
-		     data_copy_size, btrfs_leaf_data(l) +
-		     leaf_data_end(root, l), data_copy_size);
-
-	rt_data_off = BTRFS_LEAF_DATA_SIZE(root) -
-		      btrfs_item_end_nr(l, mid);
-
-	for (i = 0; i < nritems; i++) {
-		struct btrfs_item *item = btrfs_item_nr(right, i);
-		u32 ioff;
-
-		if (!right->map_token) {
-			map_extent_buffer(right, (unsigned long)item,
-					sizeof(struct btrfs_item),
-					&right->map_token, &right->kaddr,
-					&right->map_start, &right->map_len,
-					KM_USER1);
-		}
-
-		ioff = btrfs_item_offset(right, item);
-		btrfs_set_item_offset(right, item, ioff + rt_data_off);
-	}
-
-	if (right->map_token) {
-		unmap_extent_buffer(right, right->map_token, KM_USER1);
-		right->map_token = NULL;
-	}
 
-	btrfs_set_header_nritems(l, mid);
-	ret = 0;
-	btrfs_item_key(right, &disk_key, 0);
-	wret = insert_ptr(trans, root, path, &disk_key, right->start,
-			  path->slots[1] + 1, 1);
-	if (wret)
-		ret = wret;
-
-	btrfs_mark_buffer_dirty(right);
-	btrfs_mark_buffer_dirty(l);
-	BUG_ON(path->slots[0] != slot);
-
-	ret = btrfs_update_ref(trans, root, l, right, 0, nritems);
+	ret = copy_for_split(trans, root, path, l, right, slot, mid, nritems);
 	BUG_ON(ret);
 
-	if (mid <= slot) {
-		btrfs_tree_unlock(path->nodes[0]);
-		free_extent_buffer(path->nodes[0]);
-		path->nodes[0] = right;
-		path->slots[0] -= mid;
-		path->slots[1] += 1;
-	} else {
-		btrfs_tree_unlock(right);
-		free_extent_buffer(right);
-	}
-
-	BUG_ON(path->slots[0] < 0);
-
 	if (double_split) {
 		BUG_ON(num_doubles != 0);
 		num_doubles++;
 		goto again;
 	}
+
 	return ret;
 }
 
@@ -3021,26 +3078,27 @@ int btrfs_split_item(struct btrfs_trans_handle *trans,
 		return -EAGAIN;
 	}
 
+	btrfs_set_path_blocking(path);
 	ret = split_leaf(trans, root, &orig_key, path,
 			 sizeof(struct btrfs_item), 1);
 	path->keep_locks = 0;
 	BUG_ON(ret);
 
+	btrfs_unlock_up_safe(path, 1);
+	leaf = path->nodes[0];
+	BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item));
+
+split:
 	/*
 	 * make sure any changes to the path from split_leaf leave it
 	 * in a blocking state
 	 */
 	btrfs_set_path_blocking(path);
 
-	leaf = path->nodes[0];
-	BUG_ON(btrfs_leaf_free_space(root, leaf) < sizeof(struct btrfs_item));
-
-split:
 	item = btrfs_item_nr(leaf, path->slots[0]);
 	orig_offset = btrfs_item_offset(leaf, item);
 	item_size = btrfs_item_size(leaf, item);
 
-
 	buf = kmalloc(item_size, GFP_NOFS);
 	read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf,
 			    path->slots[0]), item_size);
@@ -3445,39 +3503,27 @@ out:
 }
 
 /*
- * Given a key and some data, insert items into the tree.
- * This does all the path init required, making room in the tree if needed.
+ * this is a helper for btrfs_insert_empty_items, the main goal here is
+ * to save stack depth by doing the bulk of the work in a function
+ * that doesn't call btrfs_search_slot
  */
-int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
-			    struct btrfs_root *root,
-			    struct btrfs_path *path,
-			    struct btrfs_key *cpu_key, u32 *data_size,
-			    int nr)
+static noinline_for_stack int
+setup_items_for_insert(struct btrfs_trans_handle *trans,
+		      struct btrfs_root *root, struct btrfs_path *path,
+		      struct btrfs_key *cpu_key, u32 *data_size,
+		      u32 total_data, u32 total_size, int nr)
 {
-	struct extent_buffer *leaf;
 	struct btrfs_item *item;
-	int ret = 0;
-	int slot;
-	int slot_orig;
 	int i;
 	u32 nritems;
-	u32 total_size = 0;
-	u32 total_data = 0;
 	unsigned int data_end;
 	struct btrfs_disk_key disk_key;
+	int ret;
+	struct extent_buffer *leaf;
+	int slot;
 
-	for (i = 0; i < nr; i++)
-		total_data += data_size[i];
-
-	total_size = total_data + (nr * sizeof(struct btrfs_item));
-	ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
-	if (ret == 0)
-		return -EEXIST;
-	if (ret < 0)
-		goto out;
-
-	slot_orig = path->slots[0];
 	leaf = path->nodes[0];
+	slot = path->slots[0];
 
 	nritems = btrfs_header_nritems(leaf);
 	data_end = leaf_data_end(root, leaf);
@@ -3489,9 +3535,6 @@ int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
 		BUG();
 	}
 
-	slot = path->slots[0];
-	BUG_ON(slot < 0);
-
 	if (slot != nritems) {
 		unsigned int old_data = btrfs_item_end_nr(leaf, slot);
 
@@ -3547,21 +3590,60 @@ int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
 		data_end -= data_size[i];
 		btrfs_set_item_size(leaf, item, data_size[i]);
 	}
+
 	btrfs_set_header_nritems(leaf, nritems + nr);
-	btrfs_mark_buffer_dirty(leaf);
 
 	ret = 0;
 	if (slot == 0) {
+		struct btrfs_disk_key disk_key;
 		btrfs_cpu_key_to_disk(&disk_key, cpu_key);
 		ret = fixup_low_keys(trans, root, path, &disk_key, 1);
 	}
+	btrfs_unlock_up_safe(path, 1);
+	btrfs_mark_buffer_dirty(leaf);
 
 	if (btrfs_leaf_free_space(root, leaf) < 0) {
 		btrfs_print_leaf(root, leaf);
 		BUG();
 	}
+	return ret;
+}
+
+/*
+ * Given a key and some data, insert items into the tree.
+ * This does all the path init required, making room in the tree if needed.
+ */
+int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
+			    struct btrfs_root *root,
+			    struct btrfs_path *path,
+			    struct btrfs_key *cpu_key, u32 *data_size,
+			    int nr)
+{
+	struct extent_buffer *leaf;
+	int ret = 0;
+	int slot;
+	int i;
+	u32 total_size = 0;
+	u32 total_data = 0;
+
+	for (i = 0; i < nr; i++)
+		total_data += data_size[i];
+
+	total_size = total_data + (nr * sizeof(struct btrfs_item));
+	ret = btrfs_search_slot(trans, root, cpu_key, path, total_size, 1);
+	if (ret == 0)
+		return -EEXIST;
+	if (ret < 0)
+		goto out;
+
+	leaf = path->nodes[0];
+	slot = path->slots[0];
+	BUG_ON(slot < 0);
+
+	ret = setup_items_for_insert(trans, root, path, cpu_key, data_size,
+			       total_data, total_size, nr);
+
 out:
-	btrfs_unlock_up_safe(path, 1);
 	return ret;
 }
 
@@ -3749,7 +3831,8 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 		}
 
 		/* delete the leaf if it is mostly empty */
-		if (used < BTRFS_LEAF_DATA_SIZE(root) / 4) {
+		if (used < BTRFS_LEAF_DATA_SIZE(root) / 4 &&
+		    !trans->transaction->delayed_refs.flushing) {
 			/* push_leaf_left fixes the path.
 			 * make sure the path still points to our leaf
 			 * for possible call to del_ptr below
@@ -3757,6 +3840,7 @@ int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 			slot = path->slots[1];
 			extent_buffer_get(leaf);
 
+			btrfs_set_path_blocking(path);
 			wret = push_leaf_left(trans, root, path, 1, 1);
 			if (wret < 0 && wret != -ENOSPC)
 				ret = wret;
@@ -4042,28 +4126,44 @@ next:
 int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
 {
 	int slot;
-	int level = 1;
+	int level;
 	struct extent_buffer *c;
-	struct extent_buffer *next = NULL;
+	struct extent_buffer *next;
 	struct btrfs_key key;
 	u32 nritems;
 	int ret;
+	int old_spinning = path->leave_spinning;
+	int force_blocking = 0;
 
 	nritems = btrfs_header_nritems(path->nodes[0]);
 	if (nritems == 0)
 		return 1;
 
-	btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
+	/*
+	 * we take the blocks in an order that upsets lockdep.  Using
+	 * blocking mode is the only way around it.
+	 */
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	force_blocking = 1;
+#endif
 
+	btrfs_item_key_to_cpu(path->nodes[0], &key, nritems - 1);
+again:
+	level = 1;
+	next = NULL;
 	btrfs_release_path(root, path);
+
 	path->keep_locks = 1;
+
+	if (!force_blocking)
+		path->leave_spinning = 1;
+
 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 	path->keep_locks = 0;
 
 	if (ret < 0)
 		return ret;
 
-	btrfs_set_path_blocking(path);
 	nritems = btrfs_header_nritems(path->nodes[0]);
 	/*
 	 * by releasing the path above we dropped all our locks.  A balance
@@ -4073,19 +4173,24 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
 	 */
 	if (nritems > 0 && path->slots[0] < nritems - 1) {
 		path->slots[0]++;
+		ret = 0;
 		goto done;
 	}
 
 	while (level < BTRFS_MAX_LEVEL) {
-		if (!path->nodes[level])
-			return 1;
+		if (!path->nodes[level]) {
+			ret = 1;
+			goto done;
+		}
 
 		slot = path->slots[level] + 1;
 		c = path->nodes[level];
 		if (slot >= btrfs_header_nritems(c)) {
 			level++;
-			if (level == BTRFS_MAX_LEVEL)
-				return 1;
+			if (level == BTRFS_MAX_LEVEL) {
+				ret = 1;
+				goto done;
+			}
 			continue;
 		}
 
@@ -4094,16 +4199,22 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
 			free_extent_buffer(next);
 		}
 
-		/* the path was set to blocking above */
-		if (level == 1 && (path->locks[1] || path->skip_locking) &&
-		    path->reada)
-			reada_for_search(root, path, level, slot, 0);
+		next = c;
+		ret = read_block_for_search(NULL, root, path, &next, level,
+					    slot, &key);
+		if (ret == -EAGAIN)
+			goto again;
 
-		next = read_node_slot(root, c, slot);
 		if (!path->skip_locking) {
-			WARN_ON(!btrfs_tree_locked(c));
-			btrfs_tree_lock(next);
-			btrfs_set_lock_blocking(next);
+			ret = btrfs_try_spin_lock(next);
+			if (!ret) {
+				btrfs_set_path_blocking(path);
+				btrfs_tree_lock(next);
+				if (!force_blocking)
+					btrfs_clear_path_blocking(path, next);
+			}
+			if (force_blocking)
+				btrfs_set_lock_blocking(next);
 		}
 		break;
 	}
@@ -4113,27 +4224,42 @@ int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path)
 		c = path->nodes[level];
 		if (path->locks[level])
 			btrfs_tree_unlock(c);
+
 		free_extent_buffer(c);
 		path->nodes[level] = next;
 		path->slots[level] = 0;
 		if (!path->skip_locking)
 			path->locks[level] = 1;
+
 		if (!level)
 			break;
 
-		btrfs_set_path_blocking(path);
-		if (level == 1 && path->locks[1] && path->reada)
-			reada_for_search(root, path, level, slot, 0);
-		next = read_node_slot(root, next, 0);
+		ret = read_block_for_search(NULL, root, path, &next, level,
+					    0, &key);
+		if (ret == -EAGAIN)
+			goto again;
+
 		if (!path->skip_locking) {
-			WARN_ON(!btrfs_tree_locked(path->nodes[level]));
-			btrfs_tree_lock(next);
-			btrfs_set_lock_blocking(next);
+			btrfs_assert_tree_locked(path->nodes[level]);
+			ret = btrfs_try_spin_lock(next);
+			if (!ret) {
+				btrfs_set_path_blocking(path);
+				btrfs_tree_lock(next);
+				if (!force_blocking)
+					btrfs_clear_path_blocking(path, next);
+			}
+			if (force_blocking)
+				btrfs_set_lock_blocking(next);
 		}
 	}
+	ret = 0;
 done:
 	unlock_up(path, 0, 1);
-	return 0;
+	path->leave_spinning = old_spinning;
+	if (!old_spinning)
+		btrfs_set_path_blocking(path);
+
+	return ret;
 }
 
 /*