btrfs: call functions that overwrite their root parameter with fs_info

There are 11 functions that accept a root parameter and immediately
overwrite it.  We can pass those an fs_info pointer instead.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 811662c..92c2aea 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2937,7 +2937,7 @@ int open_ctree(struct super_block *sb,
 	read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
 	   btrfs_header_chunk_tree_uuid(chunk_root->node), BTRFS_UUID_SIZE);
 
-	ret = btrfs_read_chunk_tree(chunk_root);
+	ret = btrfs_read_chunk_tree(fs_info);
 	if (ret) {
 		btrfs_err(fs_info, "failed to read chunk tree: %d", ret);
 		goto fail_tree_roots;
@@ -3038,7 +3038,7 @@ int open_ctree(struct super_block *sb,
 		goto fail_sysfs;
 	}
 
-	ret = btrfs_read_block_groups(fs_info->extent_root);
+	ret = btrfs_read_block_groups(fs_info);
 	if (ret) {
 		btrfs_err(fs_info, "failed to read block groups: %d", ret);
 		goto fail_sysfs;