Re: [PATCH 2/2] multipathd: set rport port_state to marginal for NVMe devices

[Benjamin Marzinski <bmarzins@redhat.com>]

On Fri, Dec 20, 2024 at 04:25:22PM +0530, Muneendra Kumar M wrote:
> Hi Benjamin,
> Thanks for the changes.
> But below is the reason why we didn't add support to set the rport
> port_state to marginal for NVMe devices
> 
> In the case of SCSI  once rport-state is set to Marginal ,
> If any pending I/O's on the marginal path hit's the scsi-timeout (after
> abort success) the scsi-layer checks the rport-state  and If the
> rport-state is set to Marginal it will not do any retries on the Marginal
> path instead the I/O
> Will be retried on the other Active paths.
> 
> 
> This particular functionality(checking the rport-state and acting
> accordingly) we didn't add( as far I know) in the case of NVME and we need
> to check how we can handle this in the case of NVME .
> That's the reason we didn't set the port state to Marginal in the case of
> NVMe.
> 
> 
> In a brief SCSI layer handles the case when the rport-state is set to
> Marginal whereas in NVMe it doesn't(AFIK).
> 
> Atleast with the below changes we make sure that once we get the FPIN-LI
> notification we will set the affected path , as well as the rport-state to
> Marginal irrespective of SCSI and NVMe.
> 
> I am just thinking that until we have some changes in the NVME driver to
> handle (the rport-state to marginal) this changes doesn't show any impact
> in the case of NVMe
>  other then keeping it  on par with SCSI implementation.
> 
> Please let me know your opinion on the same.

The request to do this came because the user wanted to see which target
ports were effected, but when they looked, none of them we in the
Marginal state. So there is some value in this for users, even if the
systems behavior doesn't change because of it.

-Ben

> 
> 
> Regards,
> Muneendra.
> 
> 
> 
> -----Original Message-----
> From: Benjamin Marzinski <bmarzins@redhat.com>
> Sent: Friday, December 20, 2024 7:33 AM
> To: Christophe Varoqui <christophe.varoqui@opensvc.com>
> Cc: device-mapper development <dm-devel@lists.linux.dev>; Martin Wilck
> <Martin.Wilck@suse.com>; Muneendra Kumar <muneendra.kumar@broadcom.com>
> Subject: [PATCH 2/2] multipathd: set rport port_state to marginal for NVMe
> devices
> 
> When a scsi path device is set to marginal, it updates the rport state.
> Do this for NVMe devices as well.
> 
> Fixes: 1cada778 ("multipathd: Added support to handle FPIN-Li events for
> FC-NVMe")
> Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
> ---
>  multipathd/fpin_handlers.c | 74 ++++++++++++++++++++++++++++++++++----
>  1 file changed, 68 insertions(+), 6 deletions(-)
> 
> diff --git a/multipathd/fpin_handlers.c b/multipathd/fpin_handlers.c index
> 6b56f9b7..8b436067 100644
> --- a/multipathd/fpin_handlers.c
> +++ b/multipathd/fpin_handlers.c
> @@ -15,6 +15,7 @@
>  #include "debug.h"
>  #include "util.h"
>  #include "sysfs.h"
> +#include "discovery.h"
> 
>  #include "fpin.h"
>  #include "devmapper.h"
> @@ -253,7 +254,7 @@ static int  extract_nvme_addresses_chk_path_pwwn(const
> char *address,
>   * with the els wwpn ,attached_wwpn and sets the path state to
>   * Marginal
>   */
> -static void fpin_check_set_nvme_path_marginal(uint16_t host_num, struct
> path *pp,
> +static bool fpin_check_set_nvme_path_marginal(uint16_t host_num, struct
> +path *pp,
>  		uint64_t els_wwpn, uint64_t attached_wwpn)  {
>  	struct udev_device *ctl = NULL;
> @@ -263,21 +264,79 @@ static void
> fpin_check_set_nvme_path_marginal(uint16_t host_num, struct path *pp
>  	ctl = udev_device_get_parent_with_subsystem_devtype(pp->udev,
> "nvme", NULL);
>  	if (ctl == NULL) {
>  		condlog(2, "%s: No parent device for ", pp->dev);
> -		return;
> +		return false;
>  	}
>  	address = udev_device_get_sysattr_value(ctl, "address");
>  	if (!address) {
>  		condlog(2, "%s: unable to get the address ", pp->dev);
> -		return;
> +		return false;
>  	}
>  	condlog(4, "\n address %s: dev :%s\n", address, pp->dev);
>  	ret = extract_nvme_addresses_chk_path_pwwn(address, els_wwpn,
> attached_wwpn);
>  	if (ret <= 0)
> -		return;
> +		return false;
>  	ret = fpin_add_marginal_dev_info(host_num, pp->dev);
>  	if (ret < 0)
> -		return;
> +		return false;
>  	fpin_path_setmarginal(pp);
> +	return true;
> +}
> +
> +static void fpin_nvme_set_rport_marginal(uint16_t host_num, uint64_t
> +els_wwpn) {
> +	struct udev_enumerate *udev_enum = NULL;
> +	struct udev_list_entry *entry;
> +
> +	pthread_cleanup_push(cleanup_udev_enumerate_ptr, &udev_enum);
> +	udev_enum = udev_enumerate_new(udev);
> +	if (!udev_enum) {
> +		condlog(0, "fpin: rport udev_enumerate_new() failed: %m");
> +		goto out;
> +	}
> +	if (udev_enumerate_add_match_subsystem(udev_enum,
> "fc_remote_ports") < 0 ||
> +	    udev_enumerate_add_match_is_initialized(udev_enum) < 0 ||
> +	    udev_enumerate_scan_devices(udev_enum) < 0) {
> +		condlog(0, "fpin: error setting up rport enumeration:
> %m");
> +		goto out;
> +	}
> +	udev_list_entry_foreach(entry,
> +				udev_enumerate_get_list_entry(udev_enum))
> {
> +		const char *devpath;
> +		const char *rport_id, *value;
> +		struct udev_device *rport_dev = NULL;
> +		uint16_t rport_hostnum;
> +		uint64_t rport_wwpn;
> +		unsigned int unused;
> +
> +		pthread_cleanup_push(cleanup_udev_device_ptr, &rport_dev);
> +		devpath = udev_list_entry_get_name(entry);
> +		if (!devpath)
> +			goto next;
> +		rport_id = libmp_basename(devpath);
> +		if (sscanf(rport_id, "rport-%hu:%u-%u", &rport_hostnum,
> &unused,
> +			   &unused) != 3 || rport_hostnum != host_num)
> +			goto next;
> +
> +		rport_dev = udev_device_new_from_syspath(udev, devpath);
> +		if (!rport_dev) {
> +			condlog(0, "%s: error getting rport dev: %m",
> rport_id);
> +			goto next;
> +		}
> +		value = udev_device_get_sysattr_value(rport_dev,
> "port_name");
> +		if (!value) {
> +			condlog(0, "%s: error getting port_name: %m",
> rport_id);
> +			goto next;
> +		}
> +
> +		rport_wwpn = strtol(value, NULL, 16);
> +		/* If the rport wwpn matches, set the port state to
> marginal */
> +		if (rport_wwpn == els_wwpn)
> +			fpin_set_rport_marginal(rport_dev);
> +next:
> +		pthread_cleanup_pop(1);
> +	}
> +out:
> +	pthread_cleanup_pop(1);
>  }
> 
>  /*
> @@ -338,6 +397,7 @@ static int  fpin_chk_wwn_setpath_marginal(uint16_t
> host_num,  struct vectors *ve
>  	struct multipath *mpp;
>  	int i, k;
>  	int ret = 0;
> +	bool found_nvme = false;
> 
>  	pthread_cleanup_push(cleanup_lock, &vecs->lock);
>  	lock(&vecs->lock);
> @@ -348,7 +408,7 @@ static int  fpin_chk_wwn_setpath_marginal(uint16_t
> host_num,  struct vectors *ve
>  			continue;
>  		/*checks if the bus type is nvme  and the protocol is
> FC-NVMe*/
>  		if ((pp->bus == SYSFS_BUS_NVME) && (pp->sg_id.proto_id ==
> NVME_PROTOCOL_FC)) {
> -			fpin_check_set_nvme_path_marginal(host_num, pp,
> els_wwpn, attached_wwpn);
> +			found_nvme =
> fpin_check_set_nvme_path_marginal(host_num, pp,
> +els_wwpn, attached_wwpn) || found_nvme;
>  		} else if ((pp->bus == SYSFS_BUS_SCSI) &&
>  			(pp->sg_id.proto_id == SCSI_PROTOCOL_FCP) &&
>  			(host_num ==  pp->sg_id.host_no)) {
> @@ -356,6 +416,8 @@ static int  fpin_chk_wwn_setpath_marginal(uint16_t
> host_num,  struct vectors *ve
>  			fpin_check_set_scsi_path_marginal(host_num, pp,
> els_wwpn);
>  		}
>  	}
> +	if (found_nvme)
> +		fpin_nvme_set_rport_marginal(host_num, els_wwpn);
>  	/* walk backwards because reload_and_sync_map() can remove mpp */
>  	vector_foreach_slot_backwards(vecs->mpvec, mpp, i) {
>  		if (mpp->fpin_must_reload) {
> --
> 2.46.2
> 
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