update mkfs.btrfs for the new space balancing code

The new space balancing code needs a subvol to store the
temporary inode for data extent relocation.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/mkfs.c b/mkfs.c
index 6a100640..3c09c3a9 100644
--- a/mkfs.c
+++ b/mkfs.c
@@ -232,6 +232,32 @@ static int create_raid_groups(struct btrfs_trans_handle *trans,
 	return 0;
 }
 
+static int create_data_reloc_tree(struct btrfs_trans_handle *trans,
+				  struct btrfs_root *root)
+{
+	struct btrfs_key location;
+	struct btrfs_root_item root_item;
+	struct extent_buffer *tmp;
+	u64 objectid = BTRFS_DATA_RELOC_TREE_OBJECTID;
+	int ret;
+
+	ret = btrfs_copy_root(trans, root, root->node, &tmp, objectid);
+	BUG_ON(ret);
+
+	memcpy(&root_item, &root->root_item, sizeof(root_item));
+	btrfs_set_root_bytenr(&root_item, tmp->start);
+	btrfs_set_root_level(&root_item, btrfs_header_level(tmp));
+	free_extent_buffer(tmp);
+
+	location.objectid = objectid;
+	location.type = BTRFS_ROOT_ITEM_KEY;
+	location.offset = trans->transid;
+	ret = btrfs_insert_root(trans, root->fs_info->tree_root,
+				&location, &root_item);
+	BUG_ON(ret);
+	return 0;
+}
+
 static void print_usage(void)
 {
 	fprintf(stderr, "usage: mkfs.btrfs [options] dev [ dev ... ]\n");
@@ -459,6 +485,9 @@ raid_groups:
 				 metadata_profile);
 	BUG_ON(ret);
 
+	ret = create_data_reloc_tree(trans, root);
+	BUG_ON(ret);
+
 	printf("fs created label %s on %s\n\tnodesize %u leafsize %u "
 	    "sectorsize %u size %s\n",
 	    label, first_file, nodesize, leafsize, sectorsize,