The fast-growing cloud computing market puts tremendous provisioning pressure on cloud service providers. Instead of keeping investing in costly cloud infrastructures, trading resources among different cloud service providers is another cost-effective way to expand the capacity. The key is to design an effective market-based mechanism to facilitate resource trading and motivate high-quality service provisioning. This paper proposes a distributed Feedback-based Combinatorial Multi-unit Double Auction mechanism backed by blockchain to establish a cloud resource market that not only produces high social welfare but also motivates participants to provide high-quality service. We first design an improved greedy allocation mechanism with a novel sorting method to achieve high social welfare. Then we propose a feedback-based second-price pricing mechanism to limit strategic manipulation. Finally, we design a feedback system combined with the auction mechanism to motivate high-quality service provisioning. All these mechanisms are implemented in the form of smart contracts on a consortium blockchain which guarantees the effectiveness of the feedback system and eliminates the dependence on a central auctioneer. Theoretical analysis demonstrates that the proposed auction mechanism maintains budget balance, individual rationality, truthfulness on the buyer side and computational efficiency. In comparison with other popular mechanisms, extensive experiments are conducted to demonstrate higher efficiency of the allocation mechanism, good limitation on strategic manipulation of the pricing mechanism and effectiveness of the feedback system.