These two pull requests aren't particularly exciting for Linux 3.14, the multi-queue block layer that was merged into the Linux 3.13 kernel. The Linux kernel's multi-queue block layer allows balancing I/O workload across multiple CPU cores and supports multiple hardware queues, among other features. This can lead to disk performance improvements for multi-queue systems but we didn't notice any on Linux 3.13 besides greater responsiveness. With Linux 3.14 the multi-queue block layer changes are just fixes and clean-ups.
The core block IO changes can be found by this pull request.
Within the block IO driver pull request there isn't anything too exciting but BCache has been updated, the HDD/SSD caching mechanism that was integrated into the Linux 3.10 kernel. BCache has shown promise and now with Linux 3.14 it's been further refined. There's also various fixes and small changes in this driver pull request for Linux 3.14.
While these weren't the most exciting pull requests, read about the other exciting Linux 3.14 changes. Also worth noting is that Jens Axboe is one of the latest high-profile kernel developers joining Facebook.