On Mon, Jan 07, 2019 at 01:41:47PM +0800, Qu Wenruo wrote:
> +static int insert_dirty_root(struct btrfs_trans_handle *trans,
> + struct reloc_control *rc,
> + struct btrfs_root *root)
> +{
> + struct rb_node **p = &rc->dirty_roots.rb_node;
> + struct rb_node *parent = NULL;
> + struct dirty_source_root *entry;
> + struct btrfs_root *reloc_root = root->reloc_root;
> + struct btrfs_root_item *reloc_root_item;
> + u64 root_objectid = root->root_key.objectid;
> +
> + /* @root must be a file tree root*/
> + ASSERT(root_objectid != BTRFS_TREE_RELOC_OBJECTID);
> + ASSERT(reloc_root);
> +
> + reloc_root_item = &reloc_root->root_item;
> + memset(&reloc_root_item->drop_progress, 0,
> + sizeof(reloc_root_item->drop_progress));
> + reloc_root_item->drop_level = 0;
> + btrfs_set_root_refs(reloc_root_item, 0);
> + btrfs_update_reloc_root(trans, root);
> +
> + /* We're at relocation route, not writeback route, GFP_KERNEL is OK */
> + entry = kmalloc(sizeof(*entry), GFP_KERNEL);
The open transaction also mandates GFP_NOFS, so that's another thing
to the locks and writeback constraints.
> + if (!entry)
> + return -ENOMEM;
> + btrfs_grab_fs_root(root);
> + entry->root = root;
> + while (*p) {
> + struct dirty_source_root *cur_entry;
> +
> + parent = *p;
> + cur_entry = rb_entry(parent, struct dirty_source_root, node);
> +
> + if (root_objectid < cur_entry->root->root_key.objectid)
> + p = &(*p)->rb_left;
> + else if (root_objectid > cur_entry->root->root_key.objectid)
> + p = &(*p)->rb_right;
Please stick to the coding style, { } around single statement if/else in
case they're chained and there's one multi statement block.
> + else {
> + /* This root is already dirtied */
> + btrfs_put_fs_root(root);
> + kfree(entry);
> + return 0;
> + }
> + }
> + rb_link_node(&entry->node, parent, p);
> + rb_insert_color(&entry->node, &rc->dirty_roots);
> + return 0;
> +}
