On 10/18/2016 12:40 AM, Damien Le Moal wrote:
This series introduces support for zoned block devices. It integrates earlier submissions by Hannes Reinecke and Shaun Tancheff. Compared to the previous series version, the code was significantly simplified by limiting support to zoned devices satisfying the following conditions: 1) All zones of the device are the same size, with the exception of an eventual last smaller runt zone. 2) For host-managed disks, reads must be unrestricted (read commands do not fail due to zone or write pointer alignement constraints). Zoned disks that do not satisfy these 2 conditions are ignored. These 2 conditions allowed dropping the zone information cache implemented in the previous version. This simplifies the code and also reduces the memory consumption at run time. Support for zoned devices now only require one bit per zone (less than 8KB in total). This bit field is used to write-lock zones and prevent the concurrent execution of multiple write commands in the same zone. This avoids write ordering problems at dispatch time, for both the simple queue and scsi-mq settings. The new operations introduced to suport zone manipulation was reduced to only the two main ZBC/ZAC defined commands: REPORT ZONES (REQ_OP_ZONE_REPORT) and RESET WRITE POINTER (REQ_OP_ZONE_RESET). This brings the total number of operations defined to 8, which fits in the 3 bits (REQ_OP_BITS) reserved for operation code in bio->bi_opf and req->cmd_flags. Most of the ZBC specific code is kept out of sd.c and implemented in the new file sd_zbc.c. Similarly, at the block layer, most of the zoned block device code is implemented in the new blk-zoned.c. For host-managed zoned block devices, the sequential write constraint of write pointer zones is exposed to the user. Users of the disk (applications, file systems or device mappers) must sequentially write to zones. This means that for raw block device accesses from applications, buffered writes are unreliable and direct I/Os must be used (or buffered writes with O_SYNC). Access to zone manipulation operations is also provided to applications through a set of new ioctls. This allows applications operating on raw block devices (e.g. mkfs.xxx) to discover a device zone layout and manipulate zone state.
This is starting to look mergeable to me. Any objections in getting this applied for 4.10? Looks like 6/7 should go through the SCSI tree, but I can queue up the rest. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
