nvmet: add ZBD over ZNS backend support

NVMe TP 4053 – Zoned Namespaces (ZNS) allows host software to
communicate with a non-volatile memory subsystem using zones for NVMe
protocol-based controllers. NVMeOF already support the ZNS NVMe
Protocol compliant devices on the target in the passthru mode. There
are generic zoned block devices like  Shingled Magnetic Recording (SMR)
HDDs that are not based on the NVMe protocol.

This patch adds ZNS backend support for non-ZNS zoned block devices as
NVMeOF targets.

This support includes implementing the new command set NVME_CSI_ZNS,
adding different command handlers for ZNS command set such as NVMe
Identify Controller, NVMe Identify Namespace, NVMe Zone Append,
NVMe Zone Management Send and NVMe Zone Management Receive.

With the new command set identifier, we also update the target command
effects logs to reflect the ZNS compliant commands.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 17 insertions, 9 deletions

diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c
index 019cc994efcd..0fc2781ab970 100644
--- a/drivers/nvme/target/io-cmd-bdev.c
+++ b/drivers/nvme/target/io-cmd-bdev.c
@@ -47,6 +47,14 @@ void nvmet_bdev_set_limits(struct block_device *bdev, struct nvme_id_ns *id)
 	id->nows = to0based(ql->io_opt / ql->logical_block_size);
 }
 
+void nvmet_bdev_ns_disable(struct nvmet_ns *ns)
+{
+	if (ns->bdev) {
+		blkdev_put(ns->bdev, FMODE_WRITE | FMODE_READ);
+		ns->bdev = NULL;
+	}
+}
+
 static void nvmet_bdev_ns_enable_integrity(struct nvmet_ns *ns)
 {
 	struct blk_integrity *bi = bdev_get_integrity(ns->bdev);
@@ -86,15 +94,15 @@ int nvmet_bdev_ns_enable(struct nvmet_ns *ns)
 	if (IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY_T10))
 		nvmet_bdev_ns_enable_integrity(ns);
 
-	return 0;
-}
-
-void nvmet_bdev_ns_disable(struct nvmet_ns *ns)
-{
-	if (ns->bdev) {
-		blkdev_put(ns->bdev, FMODE_WRITE | FMODE_READ);
-		ns->bdev = NULL;
+	if (bdev_is_zoned(ns->bdev)) {
+		if (!nvmet_bdev_zns_enable(ns)) {
+			nvmet_bdev_ns_disable(ns);
+			return -EINVAL;
+		}
+		ns->csi = NVME_CSI_ZNS;
 	}
+
+	return 0;
 }
 
 void nvmet_bdev_ns_revalidate(struct nvmet_ns *ns)
@@ -102,7 +110,7 @@ void nvmet_bdev_ns_revalidate(struct nvmet_ns *ns)
 	ns->size = i_size_read(ns->bdev->bd_inode);
 }
 
-static u16 blk_to_nvme_status(struct nvmet_req *req, blk_status_t blk_sts)
+u16 blk_to_nvme_status(struct nvmet_req *req, blk_status_t blk_sts)
 {
 	u16 status = NVME_SC_SUCCESS;