[$] Inline encryption for filesystems

The encryption of data at rest is increasingly mandatory in a wide range ofsettings from mobile devices to data centers. Linux has supportedencryption at both the filesystem and block-storage layers for some time,but that support comes with a cost: either the CPU must encrypt and decrypt vastamounts of data moving to and from persistent storage or it mustorchestrate offloading that work to a separate device. It wasthus only a matter of time before ways were found to offload that overhead to thestorage hardware itself. Satya Tangirala's inlineencryption patch set is intended to enable the kernel to take advantageof this hardware in a general manner.