This patchset adds support for TP8028 Rapid Path Failure Recovery for
both nvme target and initiator. Rapid Path Failure Recovery brings
Cross-Controller Reset (CCR) functionality to nvme. This allows nvme
host to send an nvme command to a source nvme controller to reset
the impacted nvme controller, provided that both source and impacted
controllers are in the same nvme subsystem.
The main use of CCR is when one path to the nvme subsystem fails.
Inflight IOs on impacted nvme controller need to be terminated first
before they can be retried on another path. Otherwise data corruption
may happen. CCR provides a quick way to terminate these IOs on the
unreachable nvme controller allowing recovery to move quickly avoiding
unnecessary delays. In case of CCR is not possible, inflight requests
are held for duration defined by TP4129 KATO Corrections and
Clarifications before they are allowed to be retried.
On the target side:
* New struct members have been added to support CCR. struct nvme_id_ctrl
has been updated with CIU (Controller Instance Uniquifier), CIRN
(Controller Instance Random Number), and CQT (Command Quiesce Time).
The combination of CIU, CNTLID, and CIRN is used to identify impacted
controller in CCR command.
* CCR nvme command implemented on the target causes impacted controller
to fail and drop connections to host.
* CCR logpage contains the status of pending CCR requests. An entry is
added to the logpage after CCR request is validated. Completed CCR
requests are removed from the logpage when controller becomes ready or
when requested in get logpage command.
* An AEN is sent when CCR completes to let the host know that it is safe
to retry inflight requests.
On the host side:
* CIU, CIRN, and CQT have been added to struct nvme_ctrl. CIU and CIRN
have been added to sysfs to make the values visible to the user.
CIU and CIRN can be used to construct and manually send admin-passthru
CCR commands.
* New controller states FENCING and FENCED have been added to make sure
that inflight request do not get canceled if they timeout during
fencing process. FENCED exists so that controller state machine does
not have a transition from FENCING to RESETTING. Instead FENCING ->
FENCED -> RESETTING. This prevents a controller being fenced from
getting reset. Only after fencing finishes the impacted controller is
reset.
* Controller recovery in nvme_fence_ctrl() is invoked when LIVE
controller hits an error or when a request times out. CCR is attempted
first to reset impacted controller. If it fails then inflight requests
are held until it is safe to retry them.
* Updated nvme fabric transports nvme-tcp, nvme-rdma, and nvme-fc to
use CCR recovery.
Ideally all inflight requests should be held during controller recovery
and only retried after recovery is done. However, there are known
situations where that is not the case in this implementation. These gaps
will be addressed in future patches:
* Manual controller reset from sysfs will result in controller going to
RESETTING state and all inflight requests to be canceled immediately
and may be retried on another path.
* Manual controller delete from sysfs will also result in all inflight
requests to be canceled immediately and may be retried on another path.
* In nvme-fc, nvme controller will be deleted if remote port disappears
with no timeout specified. This results in immediate cancellation of
requests that may be retried on another path.
* In nvme-rdma if HCA is removed all nvme controllers will be deleted.
This results in canceling inflight IOs and may be they will be retried
on another path.
Changes from v3:
- nvmet: Implement CCR nvme command
- Fixed a bug in the order of members of struct nvme_cross_ctrl_reset_cmd
- Use kmalloc_obj() instead of kmalloc()
- nvme: Implement cross-controller reset recovery
- Now CQT has been removed updated nvme_fence_ctrl() to return
success or failure instead of remaining time.
- Updated nvme_issue_wait_ccr() to respect deadline set in
nvme_fence_ctrl().
- nvme-tcp: Use CCR to recover controller that hits an error
- nvme-rdma: Use CCR to recover controller that hits an error
- Updated log nvme_fence_ctrl() return value
- nvme-fc: Refactor IO error recovery
- Updated the commit message
- Updated nvme_fc_start_ioerr_recovery() to handle
CONNECTING case first.
- nvme-fc: Use CCR to recover controller that hits an error
- Updated log nvme_fence_ctrl() return value
- nvmet: Add support for CQT to nvme target
- nvme: Add support for CQT to nvme host
- nvme: Update CCR completion wait timeout to consider CQT
- nvme-tcp: Extend FENCING state per TP4129 on CCR failure
- nvme-rdma: Extend FENCING state per TP4129 on CCR failure
- nvme-fc: Extend FENCING state per TP4129 on CCR failure
- Dropped CQT patches
v3: https://lore.kernel.org/all/20260214042753.4073668-1-mkhalfella@purestorage.com/
*** BLURB HERE ***
Mohamed Khalfella (15):
nvmet: Rapid Path Failure Recovery set controller identify fields
nvmet/debugfs: Export controller CIU and CIRN via debugfs
nvmet: Implement CCR nvme command
nvmet: Implement CCR logpage
nvmet: Send an AEN on CCR completion
nvme: Rapid Path Failure Recovery read controller identify fields
nvme: Introduce FENCING and FENCED controller states
nvme: Implement cross-controller reset recovery
nvme: Implement cross-controller reset completion
nvme-tcp: Use CCR to recover controller that hits an error
nvme-rdma: Use CCR to recover controller that hits an error
nvme-fc: Refactor IO error recovery
nvme-fc: Use CCR to recover controller that hits an error
nvme-fc: Hold inflight requests while in FENCING state
nvme-fc: Do not cancel requests in io taget before it is initialized
drivers/nvme/host/constants.c | 1 +
drivers/nvme/host/core.c | 225 +++++++++++++++++++++++++++++++-
drivers/nvme/host/fc.c | 215 +++++++++++++++++++++---------
drivers/nvme/host/nvme.h | 24 ++++
drivers/nvme/host/rdma.c | 30 ++++-
drivers/nvme/host/sysfs.c | 25 ++++
drivers/nvme/host/tcp.c | 30 ++++-
drivers/nvme/target/admin-cmd.c | 123 +++++++++++++++++
drivers/nvme/target/core.c | 110 +++++++++++++++-
drivers/nvme/target/debugfs.c | 21 +++
drivers/nvme/target/nvmet.h | 18 ++-
include/linux/nvme.h | 65 ++++++++-
12 files changed, 812 insertions(+), 75 deletions(-)
base-commit: dd09eb443372f9390d36051d86ebe06e9919aeec
--
2.52.0