btrfs: stop accessing ->free_space_root directly

We're going to have multiple free space roots in the future, so adjust
all the users of the free space root to use a helper to access the root.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/ctree.h

@@ -631,7 +631,7 @@ struct btrfs_fs_info {
 	struct btrfs_root *_csum_root;
 	struct btrfs_root *quota_root;
 	struct btrfs_root *uuid_root;
-	struct btrfs_root *free_space_root;
+	struct btrfs_root *_free_space_root;
 	struct btrfs_root *data_reloc_root;
 
 	/* the log root tree is a directory of all the other log roots */

fs/btrfs/disk-io.c

@@ -1571,8 +1571,8 @@ static struct btrfs_root *btrfs_get_global_root(struct btrfs_fs_info *fs_info,
 		return btrfs_grab_root(fs_info->uuid_root) ?
 			fs_info->uuid_root : ERR_PTR(-ENOENT);
 	if (objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
-		return btrfs_grab_root(fs_info->free_space_root) ?
-			fs_info->free_space_root : ERR_PTR(-ENOENT);
+		return btrfs_grab_root(fs_info->_free_space_root) ?
+			fs_info->_free_space_root : ERR_PTR(-ENOENT);
 	return NULL;
 }
 
@@ -1637,7 +1637,7 @@ void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
 	btrfs_put_root(fs_info->_csum_root);
 	btrfs_put_root(fs_info->quota_root);
 	btrfs_put_root(fs_info->uuid_root);
-	btrfs_put_root(fs_info->free_space_root);
+	btrfs_put_root(fs_info->_free_space_root);
 	btrfs_put_root(fs_info->fs_root);
 	btrfs_put_root(fs_info->data_reloc_root);
 	btrfs_check_leaked_roots(fs_info);
@@ -2176,7 +2176,7 @@ static void free_root_pointers(struct btrfs_fs_info *info, bool free_chunk_root)
 	free_root_extent_buffers(info->data_reloc_root);
 	if (free_chunk_root)
 		free_root_extent_buffers(info->chunk_root);
-	free_root_extent_buffers(info->free_space_root);
+	free_root_extent_buffers(info->_free_space_root);
 }
 
 void btrfs_put_root(struct btrfs_root *root)
@@ -2542,7 +2542,7 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
 			}
 		}  else {
 			set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
-			fs_info->free_space_root = root;
+			fs_info->_free_space_root = root;
 		}
 	}
 

fs/btrfs/free-space-tree.c

@@ -16,6 +16,12 @@ static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
 					struct btrfs_block_group *block_group,
 					struct btrfs_path *path);
 
+static struct btrfs_root *btrfs_free_space_root(
+				struct btrfs_block_group *block_group)
+{
+	return block_group->fs_info->_free_space_root;
+}
+
 void set_free_space_tree_thresholds(struct btrfs_block_group *cache)
 {
 	u32 bitmap_range;
@@ -51,7 +57,7 @@ static int add_new_free_space_info(struct btrfs_trans_handle *trans,
 				   struct btrfs_block_group *block_group,
 				   struct btrfs_path *path)
 {
-	struct btrfs_root *root = trans->fs_info->free_space_root;
+	struct btrfs_root *root = btrfs_free_space_root(block_group);
 	struct btrfs_free_space_info *info;
 	struct btrfs_key key;
 	struct extent_buffer *leaf;
@@ -85,7 +91,7 @@ struct btrfs_free_space_info *search_free_space_info(
 		struct btrfs_path *path, int cow)
 {
 	struct btrfs_fs_info *fs_info = block_group->fs_info;
-	struct btrfs_root *root = fs_info->free_space_root;
+	struct btrfs_root *root = btrfs_free_space_root(block_group);
 	struct btrfs_key key;
 	int ret;
 
@@ -188,7 +194,7 @@ int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
 				  struct btrfs_path *path)
 {
 	struct btrfs_fs_info *fs_info = trans->fs_info;
-	struct btrfs_root *root = fs_info->free_space_root;
+	struct btrfs_root *root = btrfs_free_space_root(block_group);
 	struct btrfs_free_space_info *info;
 	struct btrfs_key key, found_key;
 	struct extent_buffer *leaf;
@@ -326,7 +332,7 @@ int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
 				  struct btrfs_path *path)
 {
 	struct btrfs_fs_info *fs_info = trans->fs_info;
-	struct btrfs_root *root = fs_info->free_space_root;
+	struct btrfs_root *root = btrfs_free_space_root(block_group);
 	struct btrfs_free_space_info *info;
 	struct btrfs_key key, found_key;
 	struct extent_buffer *leaf;
@@ -586,7 +592,7 @@ static int modify_free_space_bitmap(struct btrfs_trans_handle *trans,
 				    struct btrfs_path *path,
 				    u64 start, u64 size, int remove)
 {
-	struct btrfs_root *root = block_group->fs_info->free_space_root;
+	struct btrfs_root *root = btrfs_free_space_root(block_group);
 	struct btrfs_key key;
 	u64 end = start + size;
 	u64 cur_start, cur_size;
@@ -699,7 +705,7 @@ static int remove_free_space_extent(struct btrfs_trans_handle *trans,
 				    struct btrfs_path *path,
 				    u64 start, u64 size)
 {
-	struct btrfs_root *root = trans->fs_info->free_space_root;
+	struct btrfs_root *root = btrfs_free_space_root(block_group);
 	struct btrfs_key key;
 	u64 found_start, found_end;
 	u64 end = start + size;
@@ -851,7 +857,7 @@ static int add_free_space_extent(struct btrfs_trans_handle *trans,
 				 struct btrfs_path *path,
 				 u64 start, u64 size)
 {
-	struct btrfs_root *root = trans->fs_info->free_space_root;
+	struct btrfs_root *root = btrfs_free_space_root(block_group);
 	struct btrfs_key key, new_key;
 	u64 found_start, found_end;
 	u64 end = start + size;
@@ -1158,7 +1164,7 @@ int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info)
 		ret = PTR_ERR(free_space_root);
 		goto abort;
 	}
-	fs_info->free_space_root = free_space_root;
+	fs_info->_free_space_root = free_space_root;
 
 	node = rb_first(&fs_info->block_group_cache_tree);
 	while (node) {
@@ -1233,7 +1239,7 @@ int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info)
 {
 	struct btrfs_trans_handle *trans;
 	struct btrfs_root *tree_root = fs_info->tree_root;
-	struct btrfs_root *free_space_root = fs_info->free_space_root;
+	struct btrfs_root *free_space_root = fs_info->_free_space_root;
 	int ret;
 
 	trans = btrfs_start_transaction(tree_root, 0);
@@ -1242,7 +1248,7 @@ int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info)
 
 	btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE);
 	btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
-	fs_info->free_space_root = NULL;
+	fs_info->_free_space_root = NULL;
 
 	ret = clear_free_space_tree(trans, free_space_root);
 	if (ret)
@@ -1320,7 +1326,7 @@ int add_block_group_free_space(struct btrfs_trans_handle *trans,
 int remove_block_group_free_space(struct btrfs_trans_handle *trans,
 				  struct btrfs_block_group *block_group)
 {
-	struct btrfs_root *root = trans->fs_info->free_space_root;
+	struct btrfs_root *root = btrfs_free_space_root(block_group);
 	struct btrfs_path *path;
 	struct btrfs_key key, found_key;
 	struct extent_buffer *leaf;
@@ -1411,7 +1417,7 @@ static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl,
 
 	block_group = caching_ctl->block_group;
 	fs_info = block_group->fs_info;
-	root = fs_info->free_space_root;
+	root = btrfs_free_space_root(block_group);
 
 	end = block_group->start + block_group->length;
 
@@ -1489,7 +1495,7 @@ static int load_free_space_extents(struct btrfs_caching_control *caching_ctl,
 
 	block_group = caching_ctl->block_group;
 	fs_info = block_group->fs_info;
-	root = fs_info->free_space_root;
+	root = btrfs_free_space_root(block_group);
 
 	end = block_group->start + block_group->length;
 

fs/btrfs/tests/free-space-tree-tests.c

@@ -446,7 +446,7 @@ static int run_test(test_func_t test_func, int bitmaps, u32 sectorsize,
 
 	btrfs_set_super_compat_ro_flags(root->fs_info->super_copy,
 					BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE);
-	root->fs_info->free_space_root = root;
+	root->fs_info->_free_space_root = root;
 	root->fs_info->tree_root = root;
 
 	root->node = alloc_test_extent_buffer(root->fs_info, nodesize);