[PATCH v7 0/6] nvme-fc: FPIN link integrity handling
Bryan Gurney
bgurney at redhat.com
Tue Jun 24 13:20:14 PDT 2025
FPIN LI (link integrity) messages are received when the attached
fabric detects hardware errors. In response to these messages I/O
should be directed away from the affected ports, and only used
if the 'optimized' paths are unavailable.
Upon port reset the paths should be put back in service as the
affected hardware might have been replaced.
This patch adds a new controller flag 'NVME_CTRL_MARGINAL'
which will be checked during multipath path selection, causing the
path to be skipped when checking for 'optimized' paths. If no
optimized paths are available the 'marginal' paths are considered
for path selection alongside the 'non-optimized' paths.
It also introduces a new nvme-fc callback 'nvme_fc_fpin_rcv()' to
evaluate the FPIN LI TLV payload and set the 'marginal' state on
all affected rports.
The testing for this patch set was performed by Bryan Gurney, using the
process outlined by John Meneghini's presentation at LSFMM 2024, where
the fibre channel switch sends an FPIN notification on a specific switch
port, and the following is checked on the initiator:
1. The controllers corresponding to the paths on the port that has
received the notification are showing a set NVME_CTRL_MARGINAL flag.
\
+- nvme4 fc traddr=c,host_traddr=e live optimized
+- nvme5 fc traddr=8,host_traddr=e live non-optimized
+- nvme8 fc traddr=e,host_traddr=f marginal optimized
+- nvme9 fc traddr=a,host_traddr=f marginal non-optimized
2. The I/O statistics of the test namespace show no I/O activity on the
controllers with NVME_CTRL_MARGINAL set.
Device tps MB_read/s MB_wrtn/s MB_dscd/s
nvme4c4n1 0.00 0.00 0.00 0.00
nvme4c5n1 25001.00 0.00 97.66 0.00
nvme4c9n1 25000.00 0.00 97.66 0.00
nvme4n1 50011.00 0.00 195.36 0.00
Device tps MB_read/s MB_wrtn/s MB_dscd/s
nvme4c4n1 0.00 0.00 0.00 0.00
nvme4c5n1 48360.00 0.00 188.91 0.00
nvme4c9n1 1642.00 0.00 6.41 0.00
nvme4n1 49981.00 0.00 195.24 0.00
Device tps MB_read/s MB_wrtn/s MB_dscd/s
nvme4c4n1 0.00 0.00 0.00 0.00
nvme4c5n1 50001.00 0.00 195.32 0.00
nvme4c9n1 0.00 0.00 0.00 0.00
nvme4n1 50016.00 0.00 195.38 0.00
Link: https://people.redhat.com/jmeneghi/LSFMM_2024/LSFMM_2024_NVMe_Cancel_and_FPIN.pdf
More rigorous testing was also performed to ensure proper path migration
on each of the eight different FPIN link integrity events, particularly
during a scenario where there are only non-optimized paths available, in
a state where all paths are marginal. On a configuration with a
round-robin iopolicy, when all paths on the host show as marginal, I/O
continues on the optimized path that was most recently non-marginal.
>From this point, of both of the optimized paths are down, I/O properly
continues on the remaining paths.
Changes to the original submission:
- Changed flag name to 'marginal'
- Do not block marginal path; influence path selection instead
to de-prioritize marginal paths
Changes to v2:
- Split off driver-specific modifications
- Introduce 'union fc_tlv_desc' to avoid casts
Changes to v3:
- Include reviews from Justin Tee
- Split marginal path handling patch
Changes to v4:
- Change 'u8' to '__u8' on fc_tlv_desc to fix a failure to build
- Print 'marginal' instead of 'live' in the state of controllers
when they are marginal
Changes to v5:
- Minor spelling corrections to patch descriptions
Changes to v6:
- No code changes; added note about additional testing
Hannes Reinecke (5):
fc_els: use 'union fc_tlv_desc'
nvme-fc: marginal path handling
nvme-fc: nvme_fc_fpin_rcv() callback
lpfc: enable FPIN notification for NVMe
qla2xxx: enable FPIN notification for NVMe
Bryan Gurney (1):
nvme: sysfs: emit the marginal path state in show_state()
drivers/nvme/host/core.c | 1 +
drivers/nvme/host/fc.c | 99 +++++++++++++++++++
drivers/nvme/host/multipath.c | 17 ++--
drivers/nvme/host/nvme.h | 6 ++
drivers/nvme/host/sysfs.c | 4 +-
drivers/scsi/lpfc/lpfc_els.c | 84 ++++++++--------
drivers/scsi/qla2xxx/qla_isr.c | 3 +
drivers/scsi/scsi_transport_fc.c | 27 +++--
include/linux/nvme-fc-driver.h | 3 +
include/uapi/scsi/fc/fc_els.h | 165 +++++++++++++++++--------------
10 files changed, 269 insertions(+), 140 deletions(-)
--
2.49.0
More information about the Linux-nvme
mailing list