[PATCH 0/3] implement zone-aware probing/wiping for zoned btrfs

[Naohiro Aota <naohiro.aota@wdc.com>]

This series implements probing and wiping of the superblock of zoned btrfs.

Zoned btrfs is merged with this series:
https://lore.kernel.org/linux-btrfs/20210222160049.GR1993@twin.jikos.cz/T/

And, superblock locations are finalized with this patch:
https://lore.kernel.org/linux-btrfs/BL0PR04MB651442E6ACBF48342BD00FEBE7719@BL0PR04MB6514.namprd04.prod.outlook.com/T/

A zoned block device consists of a number of zones. Zones are either
conventional and accepting random writes or sequential and requiring that
writes be issued in LBA order from each zone write pointer position.

Superblock (and its copies) is the only data structure in btrfs with a
fixed location on a device. Since we cannot overwrite in a sequential write
required zone, we cannot place superblock in the zone.

Thus, zoned btrfs use superblock log writing to update superblock on
sequential write required zones. It uses two zones as a circular buffer to
write updated superblocks. Once the first zone is filled up, start writing
into the second buffer. When both zones are filled up and before start
writing to the first zone again, it reset the first zone.

This series first implements zone based detection of the magic location.
Then, it adds magics for zoned btrfs and implements a probing function to
detect the latest superblock. Finally, this series also implements
zone-aware wiping by zone resetting.


Naohiro Aota (3):
  blkid: implement zone-aware probing
  blkid: add magic and probing for zoned btrfs
  blkid: support zone reset for wipefs

 configure.ac                     |   1 +
 libblkid/src/blkidP.h            |   5 +
 libblkid/src/probe.c             |  91 ++++++++++++++--
 libblkid/src/superblocks/btrfs.c | 178 ++++++++++++++++++++++++++++++-
 4 files changed, 266 insertions(+), 9 deletions(-)

-- 
2.31.1