Re: [PATCH v3 00/10] dm: zoned block device support

[Mike Snitzer <snitzer@redhat.com>]

I see quite a few issues with this patchset (only gotten through patches
1 - 6).  I'll work through it in more detail and share my
feedback/revisions tomorrow.  Mostly just cleanups, renames, etc.  But
"the fun" is obviously once I get to the last patch.

Mike

On Mon, May 08 2017 at  7:40pm -0400,
Bart Van Assche <bart.vanassche@sandisk.com> wrote:

> From: Damien Le Moal <damien.lemoal@wdc.com>
> 
> [ Note: I'm resending this patch series on Damien's behalf because Damien's ]
> [ e-mails apparently do not reach the dm-devel mailing list - Bart.         ]
> 
> This series introduces zoned block device support to the device mapper
> infrastructure. Pathces are as follows:
> 
> - Patch 1: Add a new target type feature flag to indicate if a target type
>   supports host-managed zoned block devices. This prevents using these drives
>   with the current target types since none of them have the proper support
>   implemented and will not operate properly with these drives.
> - Patch 2: If a target device is a zoned block device, check that the range of
>   LBAs mapped is aligned to the device zone size and that the device start
>   offset also aligns to zone boundaries. This is necessary for zone reset and
>   zone report correct execution.
> - Patch 3: Check that the different target devices of a table have compatible
>   zone sizes and models. This is necessary for target types that expose a zone
>   model different from the underlying device.
> - Patch 4: Fix handling of REQ_OP_ZONE_RESET bios
> - Patch 5: Fix handling of REQ_OP_ZONE_REPORT bios
> - Patch 6: Introduce a new helper function to reverse map a device zone report
>   to the target LBA range
> - Patch 7: Add support for host-managed zoned block devices to dm-flakey. This
>   is necessary for testing file systems supporting natively these drives (e.g.
>   f2fs).
> - Patch 8: Add support for for zoned block devices to dm-linear. This can have
>   useful applications during development and testing (e.g. allow creating
>   smaller zoned devices with different combinations and positions of zones).
>   There are also interesting applications for production, for instance, the
>   ability to aggregate conventional zones of different drives to create a
>   regular disk.
> - Patch 9: Add sequential write enforcement to dm_kcopyd_copy so that
>   sequential zones of a host-managed zoned block device can be specified as
>   destinations.
> - Patch 10: New dm-zoned target type (this was already sent for review twice).
>   This resend adds modifications suggested by Hannes to implement reclaim
>   using dm-kcopyd. dm-zoned depends on patch 9.
> 
> As always, comments and reviews are welcome.
> 
> Changes from v2:
> - Rebased on 4.12-rc tree
> - Added Bart Reviewed-by tag
> 
> Changes from v1:
> - Use for-loop in patch 3 as suggested by Bart
> - Add memory shrinker to dm-zoned to shrink the metadata block cache under
>   memory pressure (suggested by Bart)
> - Added Hannes Reviewed-by tag
> 
> Damien Le Moal (10):
>   dm-table: Introduce DM_TARGET_ZONED_HM feature
>   dm-table: Check device area zone alignment
>   dm-table: Check block devices zone model compatibility
>   dm: Fix REQ_OP_ZONE_RESET bio handling
>   dm: Fix REQ_OP_ZONE_REPORT bio handling
>   dm: Introduce dm_remap_zone_report()
>   dm-flakey: Add support for zoned block devices
>   dm-linear: Add support for zoned block devices
>   dm-kcopyd: Add sequential write feature
>   dm-zoned: Drive-managed zoned block device target
> 
>  Documentation/device-mapper/dm-zoned.txt |  154 +++
>  drivers/md/Kconfig                       |   17 +
>  drivers/md/Makefile                      |    2 +
>  drivers/md/dm-flakey.c                   |   21 +-
>  drivers/md/dm-kcopyd.c                   |   68 +-
>  drivers/md/dm-linear.c                   |   15 +-
>  drivers/md/dm-table.c                    |  143 ++
>  drivers/md/dm-zoned-io.c                 |  999 ++++++++++++++
>  drivers/md/dm-zoned-metadata.c           | 2225 ++++++++++++++++++++++++++++++
>  drivers/md/dm-zoned-reclaim.c            |  535 +++++++
>  drivers/md/dm-zoned.h                    |  530 +++++++
>  drivers/md/dm.c                          |   93 +-
>  include/linux/device-mapper.h            |   16 +
>  include/linux/dm-kcopyd.h                |    1 +
>  14 files changed, 4812 insertions(+), 7 deletions(-)
>  create mode 100644 Documentation/device-mapper/dm-zoned.txt
>  create mode 100644 drivers/md/dm-zoned-io.c
>  create mode 100644 drivers/md/dm-zoned-metadata.c
>  create mode 100644 drivers/md/dm-zoned-reclaim.c
>  create mode 100644 drivers/md/dm-zoned.h
> 
> -- 
> 2.9.3
>