Many Block Changes En Route To Linux 4.10

Jens Axboe has been quick to submit the block changes for the Linux 4.10 kernel and there is a wide range of improvements.

Among the highlights for the block code in Linux 4.10 include:

- Better support for O_DIRECT on block devices as well as improved support for polling with O_DIRECT via a new hybrid mode that pairs polling with an initial sleep. The long-standing O_DIRECT flag aims to minimize cache effects of I/O to/from a particular file by copying directly to the device.

- Completion tracking is done in a more scalable manner.

- Support for automatic throttling of writeback queues on the block side.

- Support for zoned block devices in the block code and SCSI ZBC (Zoned Block Commands) support. This is part of the work on Shingled Magnetic Recording (SMR).

- The NBD code now has multi-connection support for allowing user-space to provide multiple connections to a single NBD (Network Block Device) device, which paired with block-mq, can lead to much better performance.

- The block layer NVMe code has support for the WRITE_ZEROES command to set a range of blocks to zero.

- LightNVM updates. LightNVM as a refresher is the project around open-channel solid state drive support for allowing the host to manage data placement, garbage collection, and other functionality normally done by the SSD firmware.

- Various other code improvements and fixes.

More details on the block core feature changes for Linux 4.10 via this kernel mailing list message.