[PATCH v4 07/15] nvme: Introduce FENCING and FENCED controller states

Mohamed Khalfella posted 15 patches 5 days, 13 hours ago
[PATCH v4 07/15] nvme: Introduce FENCING and FENCED controller states
Posted by Mohamed Khalfella 5 days, 13 hours ago
FENCING is a new controller state that a LIVE controller enters when an
error is encountered. While in FENCING state, inflight IOs that timeout
are not canceled because they should be held until either CCR succeeds
or time-based recovery completes. While the queues remain alive, requests
are not allowed to be sent in this state, and the controller cannot be
reset or deleted. This is intentional because resetting or deleting the
controller results in canceling inflight IOs.

FENCED is a short-term state the controller enters before it is reset.
It exists only to prevent manual resets from happening while controller
is in FENCING state.

Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com>
---
 drivers/nvme/host/core.c  | 27 +++++++++++++++++++++++++--
 drivers/nvme/host/nvme.h  |  4 ++++
 drivers/nvme/host/sysfs.c |  2 ++
 3 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 7a07c23aefdb..824a1193bec8 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -574,10 +574,29 @@ bool nvme_change_ctrl_state(struct nvme_ctrl *ctrl,
 			break;
 		}
 		break;
+	case NVME_CTRL_FENCING:
+		switch (old_state) {
+		case NVME_CTRL_LIVE:
+			changed = true;
+			fallthrough;
+		default:
+			break;
+		}
+		break;
+	case NVME_CTRL_FENCED:
+		switch (old_state) {
+		case NVME_CTRL_FENCING:
+			changed = true;
+			fallthrough;
+		default:
+			break;
+		}
+		break;
 	case NVME_CTRL_RESETTING:
 		switch (old_state) {
 		case NVME_CTRL_NEW:
 		case NVME_CTRL_LIVE:
+		case NVME_CTRL_FENCED:
 			changed = true;
 			fallthrough;
 		default:
@@ -760,6 +779,8 @@ blk_status_t nvme_fail_nonready_command(struct nvme_ctrl *ctrl,
 
 	if (state != NVME_CTRL_DELETING_NOIO &&
 	    state != NVME_CTRL_DELETING &&
+	    state != NVME_CTRL_FENCING &&
+	    state != NVME_CTRL_FENCED &&
 	    state != NVME_CTRL_DEAD &&
 	    !test_bit(NVME_CTRL_FAILFAST_EXPIRED, &ctrl->flags) &&
 	    !blk_noretry_request(rq) && !(rq->cmd_flags & REQ_NVME_MPATH))
@@ -802,10 +823,12 @@ bool __nvme_check_ready(struct nvme_ctrl *ctrl, struct request *rq,
 			     req->cmd->fabrics.fctype == nvme_fabrics_type_auth_receive))
 				return true;
 			break;
-		default:
-			break;
+		case NVME_CTRL_FENCING:
+		case NVME_CTRL_FENCED:
 		case NVME_CTRL_DEAD:
 			return false;
+		default:
+			break;
 		}
 	}
 
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 234f3872a212..45e58434cf30 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -305,6 +305,8 @@ static inline u16 nvme_req_qid(struct request *req)
 enum nvme_ctrl_state {
 	NVME_CTRL_NEW,
 	NVME_CTRL_LIVE,
+	NVME_CTRL_FENCING,
+	NVME_CTRL_FENCED,
 	NVME_CTRL_RESETTING,
 	NVME_CTRL_CONNECTING,
 	NVME_CTRL_DELETING,
@@ -831,6 +833,8 @@ static inline bool nvme_state_terminal(struct nvme_ctrl *ctrl)
 	switch (nvme_ctrl_state(ctrl)) {
 	case NVME_CTRL_NEW:
 	case NVME_CTRL_LIVE:
+	case NVME_CTRL_FENCING:
+	case NVME_CTRL_FENCED:
 	case NVME_CTRL_RESETTING:
 	case NVME_CTRL_CONNECTING:
 		return false;
diff --git a/drivers/nvme/host/sysfs.c b/drivers/nvme/host/sysfs.c
index f182a26b38b0..6ae29fe431dc 100644
--- a/drivers/nvme/host/sysfs.c
+++ b/drivers/nvme/host/sysfs.c
@@ -443,6 +443,8 @@ static ssize_t nvme_sysfs_show_state(struct device *dev,
 	static const char *const state_name[] = {
 		[NVME_CTRL_NEW]		= "new",
 		[NVME_CTRL_LIVE]	= "live",
+		[NVME_CTRL_FENCING]	= "fencing",
+		[NVME_CTRL_FENCED]	= "fenced",
 		[NVME_CTRL_RESETTING]	= "resetting",
 		[NVME_CTRL_CONNECTING]	= "connecting",
 		[NVME_CTRL_DELETING]	= "deleting",
-- 
2.52.0
Re: [PATCH v4 07/15] nvme: Introduce FENCING and FENCED controller states
Posted by Hannes Reinecke 3 days, 3 hours ago
On 3/28/26 01:43, Mohamed Khalfella wrote:
> FENCING is a new controller state that a LIVE controller enters when an
> error is encountered. While in FENCING state, inflight IOs that timeout
> are not canceled because they should be held until either CCR succeeds
> or time-based recovery completes. While the queues remain alive, requests
> are not allowed to be sent in this state, and the controller cannot be
> reset or deleted. This is intentional because resetting or deleting the
> controller results in canceling inflight IOs.
> 
> FENCED is a short-term state the controller enters before it is reset.
> It exists only to prevent manual resets from happening while controller
> is in FENCING state.
> 
> Signed-off-by: Mohamed Khalfella <mkhalfella@purestorage.com>
> ---
>   drivers/nvme/host/core.c  | 27 +++++++++++++++++++++++++--
>   drivers/nvme/host/nvme.h  |  4 ++++
>   drivers/nvme/host/sysfs.c |  2 ++
>   3 files changed, 31 insertions(+), 2 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
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