diff options
Diffstat (limited to 'Documentation/ABI/testing/sysfs-block')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-block | 52 |
1 files changed, 44 insertions, 8 deletions
diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block index 71d184dbb70d..dea212db9df3 100644 --- a/Documentation/ABI/testing/sysfs-block +++ b/Documentation/ABI/testing/sysfs-block @@ -213,14 +213,8 @@ What: /sys/block/<disk>/queue/discard_zeroes_data Date: May 2011 Contact: Martin K. Petersen <martin.petersen@oracle.com> Description: - Devices that support discard functionality may return - stale or random data when a previously discarded block - is read back. This can cause problems if the filesystem - expects discarded blocks to be explicitly cleared. If a - device reports that it deterministically returns zeroes - when a discarded area is read the discard_zeroes_data - parameter will be set to one. Otherwise it will be 0 and - the result of reading a discarded area is undefined. + Will always return 0. Don't rely on any specific behavior + for discards, and don't read this file. What: /sys/block/<disk>/queue/write_same_max_bytes Date: January 2012 @@ -235,3 +229,45 @@ Description: write_same_max_bytes is 0, write same is not supported by the device. +What: /sys/block/<disk>/queue/write_zeroes_max_bytes +Date: November 2016 +Contact: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> +Description: + Devices that support write zeroes operation in which a + single request can be issued to zero out the range of + contiguous blocks on storage without having any payload + in the request. This can be used to optimize writing zeroes + to the devices. write_zeroes_max_bytes indicates how many + bytes can be written in a single write zeroes command. If + write_zeroes_max_bytes is 0, write zeroes is not supported + by the device. + +What: /sys/block/<disk>/queue/zoned +Date: September 2016 +Contact: Damien Le Moal <damien.lemoal@hgst.com> +Description: + zoned indicates if the device is a zoned block device + and the zone model of the device if it is indeed zoned. + The possible values indicated by zoned are "none" for + regular block devices and "host-aware" or "host-managed" + for zoned block devices. The characteristics of + host-aware and host-managed zoned block devices are + described in the ZBC (Zoned Block Commands) and ZAC + (Zoned Device ATA Command Set) standards. These standards + also define the "drive-managed" zone model. However, + since drive-managed zoned block devices do not support + zone commands, they will be treated as regular block + devices and zoned will report "none". + +What: /sys/block/<disk>/queue/chunk_sectors +Date: September 2016 +Contact: Hannes Reinecke <hare@suse.com> +Description: + chunk_sectors has different meaning depending on the type + of the disk. For a RAID device (dm-raid), chunk_sectors + indicates the size in 512B sectors of the RAID volume + stripe segment. For a zoned block device, either + host-aware or host-managed, chunk_sectors indicates the + size of 512B sectors of the zones of the device, with + the eventual exception of the last zone of the device + which may be smaller. |