---

yaml
---
r: 374867
b: refs/heads/master
c: 90f8d62
h: refs/heads/master
i:
  374865: 5fcd4b6
  374863: 664ad5e
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ceda08642459e31673d24d7968d864390d2ce5fa
+refs/heads/master: 90f8d62ebb55e2188c1618b650378f9857f9e9a4

trunk/fs/btrfs/ctree.c

@@ -643,15 +643,17 @@ __tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, struct extent_buffer *eb)
 static noinline int
 tree_mod_log_insert_root(struct btrfs_fs_info *fs_info,
 			 struct extent_buffer *old_root,
-			 struct extent_buffer *new_root, gfp_t flags)
+			 struct extent_buffer *new_root, gfp_t flags,
+			 int log_removal)
 {
 	struct tree_mod_elem *tm;
 	int ret;
 
 	if (tree_mod_dont_log(fs_info, NULL))
 		return 0;
 
-	__tree_mod_log_free_eb(fs_info, old_root);
+	if (log_removal)
+		__tree_mod_log_free_eb(fs_info, old_root);
 
 	ret = tree_mod_alloc(fs_info, flags, &tm);
 	if (ret < 0)
@@ -738,7 +740,7 @@ tree_mod_log_search(struct btrfs_fs_info *fs_info, u64 start, u64 min_seq)
 static noinline void
 tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
 		     struct extent_buffer *src, unsigned long dst_offset,
-		     unsigned long src_offset, int nr_items, int log_removal)
+		     unsigned long src_offset, int nr_items)
 {
 	int ret;
 	int i;
@@ -752,12 +754,10 @@ tree_mod_log_eb_copy(struct btrfs_fs_info *fs_info, struct extent_buffer *dst,
 	}
 
 	for (i = 0; i < nr_items; i++) {
-		if (log_removal) {
-			ret = tree_mod_log_insert_key_locked(fs_info, src,
-							i + src_offset,
-							MOD_LOG_KEY_REMOVE);
-			BUG_ON(ret < 0);
-		}
+		ret = tree_mod_log_insert_key_locked(fs_info, src,
+						i + src_offset,
+						MOD_LOG_KEY_REMOVE);
+		BUG_ON(ret < 0);
 		ret = tree_mod_log_insert_key_locked(fs_info, dst,
 						     i + dst_offset,
 						     MOD_LOG_KEY_ADD);
@@ -802,11 +802,12 @@ tree_mod_log_free_eb(struct btrfs_fs_info *fs_info, struct extent_buffer *eb)
 
 static noinline void
 tree_mod_log_set_root_pointer(struct btrfs_root *root,
-			      struct extent_buffer *new_root_node)
+			      struct extent_buffer *new_root_node,
+			      int log_removal)
 {
 	int ret;
 	ret = tree_mod_log_insert_root(root->fs_info, root->node,
-				       new_root_node, GFP_NOFS);
+				       new_root_node, GFP_NOFS, log_removal);
 	BUG_ON(ret < 0);
 }
 
@@ -1029,7 +1030,7 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
 			parent_start = 0;
 
 		extent_buffer_get(cow);
-		tree_mod_log_set_root_pointer(root, cow);
+		tree_mod_log_set_root_pointer(root, cow, 1);
 		rcu_assign_pointer(root->node, cow);
 
 		btrfs_free_tree_block(trans, root, buf, parent_start,
@@ -1755,7 +1756,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 			goto enospc;
 		}
 
-		tree_mod_log_set_root_pointer(root, child);
+		tree_mod_log_set_root_pointer(root, child, 1);
 		rcu_assign_pointer(root->node, child);
 
 		add_root_to_dirty_list(root);
@@ -2996,7 +2997,7 @@ static int push_node_left(struct btrfs_trans_handle *trans,
 		push_items = min(src_nritems - 8, push_items);
 
 	tree_mod_log_eb_copy(root->fs_info, dst, src, dst_nritems, 0,
-			     push_items, 1);
+			     push_items);
 	copy_extent_buffer(dst, src,
 			   btrfs_node_key_ptr_offset(dst_nritems),
 			   btrfs_node_key_ptr_offset(0),
@@ -3067,7 +3068,7 @@ static int balance_node_right(struct btrfs_trans_handle *trans,
 				      sizeof(struct btrfs_key_ptr));
 
 	tree_mod_log_eb_copy(root->fs_info, dst, src, 0,
-			     src_nritems - push_items, push_items, 1);
+			     src_nritems - push_items, push_items);
 	copy_extent_buffer(dst, src,
 			   btrfs_node_key_ptr_offset(0),
 			   btrfs_node_key_ptr_offset(src_nritems - push_items),
@@ -3091,7 +3092,7 @@ static int balance_node_right(struct btrfs_trans_handle *trans,
  */
 static noinline int insert_new_root(struct btrfs_trans_handle *trans,
 			   struct btrfs_root *root,
-			   struct btrfs_path *path, int level)
+			   struct btrfs_path *path, int level, int log_removal)
 {
 	u64 lower_gen;
 	struct extent_buffer *lower;
@@ -3142,7 +3143,7 @@ static noinline int insert_new_root(struct btrfs_trans_handle *trans,
 	btrfs_mark_buffer_dirty(c);
 
 	old = root->node;
-	tree_mod_log_set_root_pointer(root, c);
+	tree_mod_log_set_root_pointer(root, c, log_removal);
 	rcu_assign_pointer(root->node, c);
 
 	/* the super has an extra ref to root->node */
@@ -3219,18 +3220,21 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
 	int mid;
 	int ret;
 	u32 c_nritems;
-	int tree_mod_log_removal = 1;
 
 	c = path->nodes[level];
 	WARN_ON(btrfs_header_generation(c) != trans->transid);
 	if (c == root->node) {
-		/* trying to split the root, lets make a new one */
-		ret = insert_new_root(trans, root, path, level + 1);
 		/*
-		 * removal of root nodes has been logged by
-		 * tree_mod_log_set_root_pointer due to locking
+		 * trying to split the root, lets make a new one
+		 *
+		 * tree mod log: We pass 0 as log_removal parameter to
+		 * insert_new_root, because that root buffer will be kept as a
+		 * normal node. We are going to log removal of half of the
+		 * elements below with tree_mod_log_eb_copy. We're holding a
+		 * tree lock on the buffer, which is why we cannot race with
+		 * other tree_mod_log users.
 		 */
-		tree_mod_log_removal = 0;
+		ret = insert_new_root(trans, root, path, level + 1, 0);
 		if (ret)
 			return ret;
 	} else {
@@ -3268,8 +3272,7 @@ static noinline int split_node(struct btrfs_trans_handle *trans,
 			    (unsigned long)btrfs_header_chunk_tree_uuid(split),
 			    BTRFS_UUID_SIZE);
 
-	tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid,
-			     tree_mod_log_removal);
+	tree_mod_log_eb_copy(root->fs_info, split, c, 0, mid, c_nritems - mid);
 	copy_extent_buffer(split, c,
 			   btrfs_node_key_ptr_offset(0),
 			   btrfs_node_key_ptr_offset(mid),
@@ -3951,7 +3954,7 @@ static noinline int split_leaf(struct btrfs_trans_handle *trans,
 	}
 
 	if (!path->nodes[1]) {
-		ret = insert_new_root(trans, root, path, 1);
+		ret = insert_new_root(trans, root, path, 1, 1);
 		if (ret)
 			return ret;
 	}