[PATCH 0/9] nvmet: add genblk ZBD backend

[Damien Le Moal]

On 2020/11/30 12:29, Chaitanya Kulkarni wrote:
> NVMeOF Host is capable of handling the NVMe Protocol based Zoned Block
> Devices (ZBD) in the ZNS mode with the passthru backend. There is no
> support for a generic block device backend to handle the ZBD devices
> which are not NVMe devices.
> 
> This adds support to export the ZBD drives (which are not NVMe drives)
> to host from the target with NVMeOF using the host side ZNS interface.
> 
> The patch series is generated in bottom-top manner where, it first adds
> prep patch and ZNS command-specific handlers on the top of genblk and 
> updates the data structures, then one by one it wires up the admin cmds
> in the order host calls them in namespace initializing sequence. Once
> everything is ready, it wires-up the I/O command handlers. See below for 
> patch-series overview.
> 
> I've tested the ZoneFS testcases with the null_blk memory backed NVMeOF
> namespace with nvme-loop transport. The same testcases are passing on the
> NVMeOF zbd-ns and are passing for null_blk without NVMeOF .
> 
> Regards,
> Chaitanya
> 
> Changes from V1:-
> 
> 1. Remove the nvmet-$(CONFIG_BLK_DEV_ZONED) += zns.o.
> 2. Mark helpers inline.
> 3. Fix typos in the comments and update the comments.
> 4. Get rid of the curly brackets.
> 5. Don't allow drives with last smaller zones.
> 6. Calculate the zasl as a function of max_zone_append_sectors,
>    bio_max_pages so we don't have to split the bio.
> 7. Add global subsys->zasl and update the zasl when new namespace
>    is enabled.
> 8. Rmove the loop in the nvmet_bdev_execute_zone_mgmt_recv() and
>    move functionality in to the report zone callback.
> 9. Add goto for default case in nvmet_bdev_execute_zone_mgmt_send().
> 10, Allocate the zones buffer with zones size instead of bdev nr_zones.
> 
> Chaitanya Kulkarni (9):
>   block: export __bio_iov_append_get_pages()
> 	Prep patch needed for implementing Zone Append.
>   nvmet: add ZNS support for bdev-ns
> 	Core Command handlers and various helpers for ZBD backend which
> 	 will be called by target-core/target-admin etc.
>   nvmet: trim down id-desclist to use req->ns
> 	Cleanup needed to avoid the code repetation for passing extra
> 	function parameters for ZBD backend handlers.
>   nvmet: add NVME_CSI_ZNS in ns-desc for zbdev
> 	Allows host to identify zoned namesapce.
>   nvmet: add cns-cs-ctrl in id-ctrl for ZNS bdev
> 	Allows host to identify controller with the ZBD-ZNS.
>   nvmet: add cns-cs-ns in id-ctrl for ZNS bdev
> 	Allows host to identify namespace with the ZBD-ZNS.
>   nvmet: add zns cmd effects to support zbdev
> 	Allows host to support the ZNS commands when zoned-blkdev is
> 	 selected.
>   nvmet: add zns bdev config support
> 	Allows user to override any target namespace attributes for
> 	 ZBD.
>   nvmet: add ZNS based I/O cmds handlers
> 	Handlers for Zone-Mgmt-Send/Zone-Mgmt-Recv/Zone-Append.
> 
>  block/bio.c                       |   3 +-
>  drivers/nvme/target/Makefile      |   2 +-
>  drivers/nvme/target/admin-cmd.c   |  38 ++-
>  drivers/nvme/target/io-cmd-bdev.c |  12 +
>  drivers/nvme/target/io-cmd-file.c |   2 +-
>  drivers/nvme/target/nvmet.h       |  19 ++
>  drivers/nvme/target/zns.c         | 463 ++++++++++++++++++++++++++++++
>  include/linux/bio.h               |   1 +
>  8 files changed, 524 insertions(+), 16 deletions(-)
>  create mode 100644 drivers/nvme/target/zns.c
> 

I had a few questions about the failed zonefs tests that you reported in the
cover letter of V1. Did you run the tests again with V2 ? Do you still see the
errors or not ?


-- 
Damien Le Moal
Western Digital Research