[PATCH RFC 0/2] dm-zoned: add cache device

[Hannes Reinecke <hare@suse.de>]

Hi Damien,

as my original plan to upgrade bcache to work for SMR devices
turned out to be more complex than anticipated I went for the
simpler approach and added a 'cache' device for dm-zoned.
It is using a normal device (eg '/dev/pmem0' :-), split it
into zones of the same size of the original SMR device, and
makes those 'virtual' zones avialable to dm-zoned in a similar
manner than the existing 'random write' zoned.

The implementation is still a bit rough (one would need to add
metadata to the cache device, too), but so far it seems to work
quite well; still running after copying 300GB of data back and forth.

As usual, comments and reviews are welcome.

Hannes Reinecke (2):
  dm-zoned: cache device for zones
  dm-zoned: add 'status' and 'message' callbacks

 drivers/md/dm-zoned-metadata.c | 189 +++++++++++++++++++++++++++++----
 drivers/md/dm-zoned-reclaim.c  |  76 ++++++++++---
 drivers/md/dm-zoned-target.c   | 159 ++++++++++++++++++++++++---
 drivers/md/dm-zoned.h          |  34 +++++-
 4 files changed, 407 insertions(+), 51 deletions(-)

-- 
2.25.0