[dm-devel] [PATCH 14/19] multipath-tools: add ANA support for NVMe device

[Hannes Reinecke]

On 12/19/18 12:19 AM, Martin Wilck wrote:
> From: lijie <lijie34 at huawei.com>
> 
> Add support for Asynchronous Namespace Access as specified in NVMe 1.3
> TP 4004. The states are updated through reading the ANA log page.
> 
> By default, the native nvme multipath takes over the nvme device.
> We can pass a false to the parameter 'multipath' of the nvme-core.ko
> module,when we want to use multipath-tools.
> 
> Signed-off-by: Martin Wilck <mwilck at suse.com>
> ---
>   libmultipath/prio.h                |   1 +
>   libmultipath/prioritizers/Makefile |   1 +
>   libmultipath/prioritizers/ana.c    | 292 +++++++++++++++++++++++++++++
>   libmultipath/prioritizers/ana.h    | 221 ++++++++++++++++++++++
>   multipath/multipath.conf.5         |   8 +
>   5 files changed, 523 insertions(+)
>   create mode 100644 libmultipath/prioritizers/ana.c
>   create mode 100644 libmultipath/prioritizers/ana.h
> 
> diff --git a/libmultipath/prio.h b/libmultipath/prio.h
> index aa587ccd..599d1d88 100644
> --- a/libmultipath/prio.h
> +++ b/libmultipath/prio.h
> @@ -30,6 +30,7 @@ struct path;
>   #define PRIO_WEIGHTED_PATH	"weightedpath"
>   #define PRIO_SYSFS		"sysfs"
>   #define PRIO_PATH_LATENCY	"path_latency"
> +#define PRIO_ANA		"ana"
>   
>   /*
>    * Value used to mark the fact prio was not defined
> diff --git a/libmultipath/prioritizers/Makefile b/libmultipath/prioritizers/Makefile
> index ab7bc075..15afaba3 100644
> --- a/libmultipath/prioritizers/Makefile
> +++ b/libmultipath/prioritizers/Makefile
> @@ -19,6 +19,7 @@ LIBS = \
>   	libpriordac.so \
>   	libprioweightedpath.so \
>   	libpriopath_latency.so \
> +	libprioana.so \
>   	libpriosysfs.so
>   
>   all: $(LIBS)
> diff --git a/libmultipath/prioritizers/ana.c b/libmultipath/prioritizers/ana.c
> new file mode 100644
> index 00000000..c5aaa5fb
> --- /dev/null
> +++ b/libmultipath/prioritizers/ana.c
> @@ -0,0 +1,292 @@
> +/*
> + * (C) Copyright HUAWEI Technology Corp. 2017   All Rights Reserved.
> + *
> + * ana.c
> + * Version 1.00
> + *
> + * Tool to make use of a NVMe-feature called  Asymmetric Namespace Access.
> + * It determines the ANA state of a device and prints a priority value to stdout.
> + *
> + * Author(s): Cheng Jike <chengjike.cheng at huawei.com>
> + *            Li Jie <lijie34 at huawei.com>
> + *
> + * This file is released under the GPL version 2, or any later version.
> + */
> +#include <stdio.h>
> +#include <sys/ioctl.h>
> +#include <sys/stat.h>
> +#include <sys/types.h>
> +#include <stdbool.h>
> +
> +#include "debug.h"
> +#include "prio.h"
> +#include "structs.h"
> +#include "ana.h"
> +
> +enum {
> +	ANA_PRIO_OPTIMIZED		= 50,
> +	ANA_PRIO_NONOPTIMIZED		= 10,
> +	ANA_PRIO_INACCESSIBLE		= 5,
> +	ANA_PRIO_PERSISTENT_LOSS	= 1,
> +	ANA_PRIO_CHANGE			= 0,
> +	ANA_PRIO_RESERVED		= 0,
> +	ANA_PRIO_GETCTRL_FAILED		= -1,
> +	ANA_PRIO_NOT_SUPPORTED		= -2,
> +	ANA_PRIO_GETANAS_FAILED		= -3,
> +	ANA_PRIO_GETANALOG_FAILED	= -4,
> +	ANA_PRIO_GETNSID_FAILED		= -5,
> +	ANA_PRIO_GETNS_FAILED		= -6,
> +	ANA_PRIO_NO_MEMORY		= -7,
> +	ANA_PRIO_NO_INFORMATION		= -8,
> +};

Please model the priorities according to the ALUA handler; ANA state 
'persistent loss' maps onto ALUA 'unavailable' (and hence should have a 
priority of '0'), and ANA state 'inaccessible' is roughly similar to 
ALUA 'standby', hence should have a priority of '1'.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		   Teamlead Storage & Networking
hare at suse.de			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)