btrfs-progs: mkfs: Move the tree root creation to own function

make_btrfs is too long to understand, make creatation of root tree
in a function.

Some of the tree roots are now created in a loop, where the code is just
copypasted. We now make use of the reference_root_table to translate
block index to root objectid.

Signed-off-by: Gu Jinxiang <gujx@cn.fujitsu.com>
[ updated changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/mkfs/common.c b/mkfs/common.c
index 7d482c2..c9ce10d 100644 (file)
--- a/mkfs/common.c
+++ b/mkfs/common.c
@@ -34,6 +34,67 @@ static u64 reference_root_table[] = {
        [6] =   BTRFS_CSUM_TREE_OBJECTID,
 };
 
+static int btrfs_create_tree_root(int fd, struct btrfs_mkfs_config *cfg,
+                       struct extent_buffer *buf)
+{
+       struct btrfs_root_item root_item;
+       struct btrfs_inode_item *inode_item;
+       struct btrfs_disk_key disk_key;
+       u32 nritems = 0;
+       u32 itemoff;
+       int ret = 0;
+       int blk;
+
+       memset(buf->data + sizeof(struct btrfs_header), 0,
+               cfg->nodesize - sizeof(struct btrfs_header));
+       memset(&root_item, 0, sizeof(root_item));
+       memset(&disk_key, 0, sizeof(disk_key));
+
+       /* create the items for the root tree */
+       inode_item = &root_item.inode;
+       btrfs_set_stack_inode_generation(inode_item, 1);
+       btrfs_set_stack_inode_size(inode_item, 3);
+       btrfs_set_stack_inode_nlink(inode_item, 1);
+       btrfs_set_stack_inode_nbytes(inode_item, cfg->nodesize);
+       btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
+       btrfs_set_root_refs(&root_item, 1);
+       btrfs_set_root_used(&root_item, cfg->nodesize);
+       btrfs_set_root_generation(&root_item, 1);
+
+       btrfs_set_disk_key_type(&disk_key, BTRFS_ROOT_ITEM_KEY);
+       btrfs_set_disk_key_offset(&disk_key, 0);
+       itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize) - sizeof(root_item);
+
+       for (blk = 0; blk < MKFS_BLOCK_COUNT; blk++) {
+               if (blk == MKFS_SUPER_BLOCK || blk == MKFS_ROOT_TREE
+                   || blk == MKFS_CHUNK_TREE)
+                       continue;
+
+               btrfs_set_root_bytenr(&root_item, cfg->blocks[blk]);
+               btrfs_set_disk_key_objectid(&disk_key,
+                       reference_root_table[blk]);
+               btrfs_set_item_key(buf, &disk_key, nritems);
+               btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
+               btrfs_set_item_size(buf, btrfs_item_nr(nritems),
+                               sizeof(root_item));
+               write_extent_buffer(buf, &root_item,
+                       btrfs_item_ptr_offset(buf, nritems),
+                       sizeof(root_item));
+               nritems++;
+               itemoff -= sizeof(root_item);
+       }
+
+       /* generate checksum */
+       csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
+
+       /* write back root tree */
+       ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[MKFS_ROOT_TREE]);
+       if (ret != cfg->nodesize)
+               return (ret < 0 ? -errno : -EIO);
+
+       return ret;
+}
+
 /*
  * @fs_uuid - if NULL, generates a UUID, returns back the new filesystem UUID
  *
@@ -44,10 +105,8 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
 {
        struct btrfs_super_block super;
        struct extent_buffer *buf;
-       struct btrfs_root_item root_item;
        struct btrfs_disk_key disk_key;
        struct btrfs_extent_item *extent_item;
-       struct btrfs_inode_item *inode_item;
        struct btrfs_chunk *chunk;
        struct btrfs_dev_item *dev_item;
        struct btrfs_dev_extent *dev_extent;
@@ -133,77 +192,9 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
                            btrfs_header_chunk_tree_uuid(buf),
                            BTRFS_UUID_SIZE);
 
-       /* create the items for the root tree */
-       memset(&root_item, 0, sizeof(root_item));
-       inode_item = &root_item.inode;
-       btrfs_set_stack_inode_generation(inode_item, 1);
-       btrfs_set_stack_inode_size(inode_item, 3);
-       btrfs_set_stack_inode_nlink(inode_item, 1);
-       btrfs_set_stack_inode_nbytes(inode_item, cfg->nodesize);
-       btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
-       btrfs_set_root_refs(&root_item, 1);
-       btrfs_set_root_used(&root_item, cfg->nodesize);
-       btrfs_set_root_generation(&root_item, 1);
-
-       memset(&disk_key, 0, sizeof(disk_key));
-       btrfs_set_disk_key_type(&disk_key, BTRFS_ROOT_ITEM_KEY);
-       btrfs_set_disk_key_offset(&disk_key, 0);
-       nritems = 0;
-
-       itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize) - sizeof(root_item);
-       btrfs_set_root_bytenr(&root_item, cfg->blocks[MKFS_EXTENT_TREE]);
-       btrfs_set_disk_key_objectid(&disk_key, BTRFS_EXTENT_TREE_OBJECTID);
-       btrfs_set_item_key(buf, &disk_key, nritems);
-       btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
-       btrfs_set_item_size(buf, btrfs_item_nr(nritems),
-                           sizeof(root_item));
-       write_extent_buffer(buf, &root_item, btrfs_item_ptr_offset(buf,
-                           nritems), sizeof(root_item));
-       nritems++;
-
-       itemoff = itemoff - sizeof(root_item);
-       btrfs_set_root_bytenr(&root_item, cfg->blocks[MKFS_DEV_TREE]);
-       btrfs_set_disk_key_objectid(&disk_key, BTRFS_DEV_TREE_OBJECTID);
-       btrfs_set_item_key(buf, &disk_key, nritems);
-       btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
-       btrfs_set_item_size(buf, btrfs_item_nr(nritems),
-                           sizeof(root_item));
-       write_extent_buffer(buf, &root_item,
-                           btrfs_item_ptr_offset(buf, nritems),
-                           sizeof(root_item));
-       nritems++;
-
-       itemoff = itemoff - sizeof(root_item);
-       btrfs_set_root_bytenr(&root_item, cfg->blocks[MKFS_FS_TREE]);
-       btrfs_set_disk_key_objectid(&disk_key, BTRFS_FS_TREE_OBJECTID);
-       btrfs_set_item_key(buf, &disk_key, nritems);
-       btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
-       btrfs_set_item_size(buf, btrfs_item_nr(nritems),
-                           sizeof(root_item));
-       write_extent_buffer(buf, &root_item,
-                           btrfs_item_ptr_offset(buf, nritems),
-                           sizeof(root_item));
-       nritems++;
-
-       itemoff = itemoff - sizeof(root_item);
-       btrfs_set_root_bytenr(&root_item, cfg->blocks[MKFS_CSUM_TREE]);
-       btrfs_set_disk_key_objectid(&disk_key, BTRFS_CSUM_TREE_OBJECTID);
-       btrfs_set_item_key(buf, &disk_key, nritems);
-       btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
-       btrfs_set_item_size(buf, btrfs_item_nr(nritems),
-                           sizeof(root_item));
-       write_extent_buffer(buf, &root_item,
-                           btrfs_item_ptr_offset(buf, nritems),
-                           sizeof(root_item));
-       nritems++;
-
-
-       csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
-       ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[MKFS_ROOT_TREE]);
-       if (ret != cfg->nodesize) {
-               ret = (ret < 0 ? -errno : -EIO);
+       ret = btrfs_create_tree_root(fd, cfg, buf);
+       if (ret < 0)
                goto out;
-       }
 
        /* create the items for the extent tree */
        memset(buf->data + sizeof(struct btrfs_header), 0,