Hello Lijie,

On Thu, 2018-11-08 at 14:09 +0800, lijie wrote:
> 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.

Thank you for the patch. It looks quite good to me. I've tested it with
a Linux target and found no problems so far.

I have a few questions and comments inline below.

I suggest you also have a look at detect_prio(); it seems to make sense
to use the ana prioritizer for NVMe paths automatically if ANA is
supported (with your patch, "detect_prio no" and "prio ana" have to be
configured explicitly). But that can be done in a later patch.

Martin

> ---
>  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 aa587cc..599d1d8 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 ab7bc07..15afaba 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 0000000..c5aaa5f
> --- /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.ch...@huawei.com>
> + *            Li Jie <liji...@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,
> +};
> +
> +static const char * anas_string[] = {
> +     [NVME_ANA_OPTIMIZED]                    = "ANA Optimized
> State",
> +     [NVME_ANA_NONOPTIMIZED]                 = "ANA Non-Optimized
> State",
> +     [NVME_ANA_INACCESSIBLE]                 = "ANA Inaccessible
> State",
> +     [NVME_ANA_PERSISTENT_LOSS]              = "ANA Persistent
> Loss State",
> +     [NVME_ANA_CHANGE]                       = "ANA Change state",
> +     [NVME_ANA_RESERVED]                     = "Invalid namespace
> group state!",
> +};
> +
> +static const char *aas_print_string(int rc)
> +{
> +     rc &= 0xff;
> +
> +     switch(rc) {
> +     case NVME_ANA_OPTIMIZED:
> +     case NVME_ANA_NONOPTIMIZED:
> +     case NVME_ANA_INACCESSIBLE:
> +     case NVME_ANA_PERSISTENT_LOSS:
> +     case NVME_ANA_CHANGE:
> +             return anas_string[rc];
> +     default:
> +             return anas_string[NVME_ANA_RESERVED];
> +     }
> +
> +     return anas_string[NVME_ANA_RESERVED];
> +}

nit: the last statement is superfluous.

> +
> +static int nvme_get_nsid(int fd, unsigned *nsid)
> +{
> +     static struct stat nvme_stat;
> +     int err = fstat(fd, &nvme_stat);
> +     if (err < 0)
> +             return 1;
> +
> +     if (!S_ISBLK(nvme_stat.st_mode)) {
> +             condlog(0, "Error: requesting namespace-id from non-
> block device\n");
> +             return 1;
> +     }
> +
> +     *nsid = ioctl(fd, NVME_IOCTL_ID);
> +     return 0;
> +}
> +
> +static int nvme_submit_admin_passthru(int fd, struct
> nvme_passthru_cmd *cmd)
> +{
> +     return ioctl(fd, NVME_IOCTL_ADMIN_CMD, cmd);
> +}
> +
> +int nvme_get_log13(int fd, __u32 nsid, __u8 log_id, __u8 lsp, __u64
> lpo,
> +                 __u16 lsi, bool rae, __u32 data_len, void *data)

lpo and lsi are 0 in all callers.  Likewise, rae is always true. You
might consider simplifying your code by omitting these paramters.

I can see that you did it this way because you have copied the code
from nvme-cli/nvme-ioctl.c, which is fine. In this case, however, we
may want to copy the entire file, in order to be able to track more
easily if our code is up-to-date. I wish something like libnvmecli
existed.

> +{
> +     struct nvme_admin_cmd cmd = {
> +             .opcode         = nvme_admin_get_log_page,
> +             .nsid           = nsid,
> +             .addr           = (__u64)(uintptr_t) data,
> +             .data_len       = data_len,
> +     };
> +     __u32 numd = (data_len >> 2) - 1;
> +     __u16 numdu = numd >> 16, numdl = numd & 0xffff;
> +
> +     cmd.cdw10 = log_id | (numdl << 16) | (rae ? 1 << 15 : 0);
> +     if (lsp)log143
> +             cmd.cdw10 |= lsp << 8;
> +
> +     cmd.cdw11 = numdu | (lsi << 16);
> +     cmd.cdw12 = lpo;
> +     cmd.cdw13 = (lpo >> 32);
> +
> +     return nvme_submit_admin_passthru(fd, &cmd);
> +
> +}
> +
> +int nvme_identify13(int fd, __u32 nsid, __u32 cdw10, __u32 cdw11,
> void *data)
> +{
> +     struct nvme_admin_cmd cmd = {
> +             .opcode         = nvme_admin_identify,
> +             .nsid           = nsid,
> +             .addr           = (__u64)(uintptr_t) data,
> +             .data_len       = NVME_IDENTIFY_DATA_SIZE,
> +             .cdw10          = cdw10,
> +             .cdw11          = cdw11,

Along similar lines as above, this could be simplified, as cdw11 is
never used.

> +     };
> +
> +     return nvme_submit_admin_passthru(fd, &cmd);
> +}
> +
> +int nvme_identify(int fd, __u32 nsid, __u32 cdw10, void *data)
> +{
> +     return nvme_identify13(fd, nsid, cdw10, 0, data);
> +}
> +
> +int nvme_identify_ctrl(int fd, void *data)
> +{
> +     return nvme_identify(fd, 0, NVME_ID_CNS_CTRL, data);
> +}
> +
> +int nvme_identify_ns(int fd, __u32 nsid, void *data)
> +{
> +     return nvme_identify(fd, nsid, NVME_ID_CNS_NS, data);
> +}
> +
> +int nvme_ana_log(int fd, void *ana_log, size_t ana_log_len, int rgo)
> +{
> +     __u64 lpo = 0;
> +
> +     return nvme_get_log13(fd, NVME_NSID_ALL, NVME_LOG_ANA, rgo,
> lpo, 0,
> +                     true, ana_log_len, ana_log);
> +}
> +
> +static int get_ana_state(__u32 nsid, __u32 anagrpid, void *ana_log)
> +{
> +     int     rc = ANA_PRIO_GETANAS_FAILED;
> +     void *base = ana_log;
> +     struct nvme_ana_rsp_hdr *hdr = base;
> +     struct nvme_ana_group_desc *ana_desc;
> +     int offset = sizeof(struct nvme_ana_rsp_hdr);
> +     __u32 nr_nsids;
> +     size_t nsid_buf_size;
> +     int i, j;
> +
> +     for (i = 0; i < le16_to_cpu(hdr->ngrps); i++) {
> +             ana_desc = base + offset;
> +             nr_nsids = le32_to_cpu(ana_desc->nnsids);
> +             nsid_buf_size = nr_nsids * sizeof(__le32);
> +
> +             offset += sizeof(*ana_desc);
> +
> +             for (j = 0; j < nr_nsids; j++) {
> +                     if (nsid == le32_to_cpu(ana_desc->nsids[j]))
> +                             return ana_desc->state;
> +             }
> +
> +             if (anagrpid != 0 && anagrpid == le32_to_cpu(ana_desc-
> >grpid))
> +                     rc = ana_desc->state;


Shouldn't you check this condition before iterating over the nsids?
And if the anagrpid matches, shouldn't you return the state
immediately?

Some comments would be helpful in order to understand this logic.

> +
> +             offset += nsid_buf_size;
> +     }
> +
> +     return rc;
> +}
> +
> +int get_ana_info(struct path * pp, unsigned int timeout)

This should be a static function.

> +{
> +     int     rc;
> +     __u32 nsid;
> +     struct nvme_id_ctrl ctrl;
> +     struct nvme_id_ns ns;
> +     void *ana_log;
> +     size_t ana_log_len;
> +
> +     rc = nvme_identify_ctrl(pp->fd, &ctrl);
> +     if (rc)
> +             return ANA_PRIO_GETCTRL_FAILED;
> +
> +     if(!(ctrl.cmic & (1 << 3)))
> +             return ANA_PRIO_NOT_SUPPORTED;
> +
> +     rc = nvme_get_nsid(pp->fd, &nsid);
> +     if (rc)
> +             return ANA_PRIO_GETNSID_FAILED;
> +
> +     rc = nvme_identify_ns(pp->fd, nsid, &ns);
> +     if (rc)
> +             return ANA_PRIO_GETNS_FAILED;
> +
> +     ana_log_len = sizeof(struct nvme_ana_rsp_hdr) +
> +             le32_to_cpu(ctrl.nanagrpid) * sizeof(struct
> nvme_ana_group_desc);
> +     if (!(ctrl.anacap & (1 << 6)))
> +             ana_log_len += le32_to_cpu(ctrl.mnan) * sizeof(__le32);

I'd like to see a sanity check for ana_log_len here.

> +
> +     ana_log = malloc(ana_log_len);
> +     if (!ana_log)
> +             return ANA_PRIO_NO_MEMORY;
> +
> +     rc = nvme_ana_log(pp->fd, ana_log, ana_log_len,
> +             (ctrl.anacap & (1 << 6)) ? NVME_ANA_LOG_RGO : 0);
> +     if (rc) {
> +             free(ana_log);
> +             return ANA_PRIO_GETANALOG_FAILED;
> +     }

Please use a "goto error;" like construct here.

> +
> +     rc = get_ana_state(nsid, le32_to_cpu(ns.anagrpid), ana_log);
> +     if (rc < 0){
> +             free(ana_log);
> +             return ANA_PRIO_GETANAS_FAILED;
> +     }
> +
> +     free(ana_log);
> +     condlog(3, "%s: ana state = %02x [%s]", pp->dev, rc,
> aas_print_string(rc));

Please put an "error:" label here and free ana_log there.

> +
> +     return rc;
> +}
> +
> +int getprio(struct path * pp, char * args, unsigned int timeout)
> +{
> +     int rc;
> +
> +     if (pp->fd < 0)
> +             return ANA_PRIO_NO_INFORMATION;
> +
> +     rc = get_ana_info(pp, timeout);
> +     if (rc >= 0) {
> +             rc &= 0x0f;
> +             switch(rc) {
> +             case NVME_ANA_OPTIMIZED:
> +                     rc = ANA_PRIO_OPTIMIZED;
> +                     break;
> +             case NVME_ANA_NONOPTIMIZED:
> +                     rc = ANA_PRIO_NONOPTIMIZED;
> +                     break;
> +             case NVME_ANA_INACCESSIBLE:
> +                     rc = ANA_PRIO_INACCESSIBLE;
> +                     break;
> +             case NVME_ANA_PERSISTENT_LOSS:
> +                     rc = ANA_PRIO_PERSISTENT_LOSS;
> +                     break;
> +             case NVME_ANA_CHANGE:
> +                     rc = ANA_PRIO_CHANGE;
> +                     break;
> +             default:
> +                     rc = ANA_PRIO_RESERVED;
> +             }
> +     } else {
> +             switch(rc) {
> +             case ANA_PRIO_GETCTRL_FAILED:
> +                     condlog(0, "%s: couldn't get ctrl info", pp-
> >dev);
> +                     break;
> +             case ANA_PRIO_NOT_SUPPORTED:
> +                     condlog(0, "%s: ana not supported", pp->dev);
> +                     break;
> +             case ANA_PRIO_GETANAS_FAILED:
> +                     condlog(0, "%s: couldn't get ana state", pp-
> >dev);
> +                     break;
> +             case ANA_PRIO_GETANALOG_FAILED:
> +                     condlog(0, "%s: couldn't get ana log", pp-
> >dev);
> +                     break;
> +             case ANA_PRIO_GETNS_FAILED:
> +                     condlog(0, "%s: couldn't get namespace", pp-
> >dev);
> +                     break;
> +             case ANA_PRIO_GETNSID_FAILED:
> +                     condlog(0, "%s: couldn't get namespace id", pp-
> >dev);
> +                     break;
> +             case ANA_PRIO_NO_MEMORY:
> +                     condlog(0, "%s: couldn't alloc memory", pp-
> >dev);
> +                     break;
> +             }
> +     }
> +     return rc;
> +}
> +
> diff --git a/libmultipath/prioritizers/ana.h
> b/libmultipath/prioritizers/ana.h
> new file mode 100644
> index 0000000..92cfa9e
> --- /dev/null
> +++ b/libmultipath/prioritizers/ana.h
> @@ -0,0 +1,221 @@
> +#ifndef _ANA_H
> +#define _ANA_H
> +
> +#include <linux/types.h>
> +
> +#define NVME_NSID_ALL                        0xffffffff
> +#define NVME_IDENTIFY_DATA_SIZE      4096
> +
> +#define NVME_LOG_ANA                 0x0c
> +
> +/* Admin commands */
> +enum nvme_admin_opcode {
> +     nvme_admin_get_log_page         = 0x02,
> +     nvme_admin_identify             = 0x06,
> +};
> +
> +enum {
> +     NVME_ID_CNS_NS                  = 0x00,
> +     NVME_ID_CNS_CTRL                = 0x01,
> +};
> +
> +/* nvme ioctl start */
> +struct nvme_passthru_cmd {
> +     __u8    opcode;
> +     __u8    flags;
> +     __u16   rsvd1;
> +     __u32   nsid;
> +     __u32   cdw2;
> +     __u32   cdw3;
> +     __u64   metadata;
> +     __u64   addr;
> +     __u32   metadata_len;
> +     __u32   data_len;
> +     __u32   cdw10;
> +     __u32   cdw11;
> +     __u32   cdw12;
> +     __u32   cdw13;
> +     __u32   cdw14;
> +     __u32   cdw15;
> +     __u32   timeout_ms;
> +     __u32   result;
> +};
> +
> +#define nvme_admin_cmd nvme_passthru_cmd
> +
> +#define NVME_IOCTL_ID                _IO('N', 0x40)
> +#define NVME_IOCTL_ADMIN_CMD _IOWR('N', 0x41, struct nvme_admin_cmd)
> +/* nvme ioctl end */

Please #include <linux/nvme_ioctl.h> rather than copying its contents
here.

> +
> +/* nvme id ctrl start */
> +struct nvme_id_power_state {
> +     __le16                  max_power;      /* centiwatts */
> +     __u8                    rsvd2;
> +     __u8                    flags;
> +     __le32                  entry_lat;      /* microseconds */
> +     __le32                  exit_lat;       /* microseconds */
> +     __u8                    read_tput;
> +     __u8                    read_lat;
> +     __u8                    write_tput;
> +     __u8                    write_lat;
> +     __le16                  idle_power;
> +     __u8                    idle_scale;
> +     __u8                    rsvd19;
> +     __le16                  active_power;
> +     __u8                    active_work_scale;
> +     __u8                    rsvd23[9];
> +};
> +
> +struct nvme_id_ctrl {
> +     __le16                  vid;
> +     __le16                  ssvid;
> +     char                    sn[20];
> +     char                    mn[40];
> +     char                    fr[8];
> +     __u8                    rab;
> +     __u8                    ieee[3];
> +     __u8                    cmic;
> +     __u8                    mdts;
> +     __le16                  cntlid;
> +     __le32                  ver;
> +     __le32                  rtd3r;
> +     __le32                  rtd3e;
> +     __le32                  oaes;
> +     __le32                  ctratt;
> +     __u8                    rsvd100[156];
> +     __le16                  oacs;
> +     __u8                    acl;
> +     __u8                    aerl;
> +     __u8                    frmw;
> +     __u8                    lpa;
> +     __u8                    elpe;
> +     __u8                    npss;
> +     __u8                    avscc;
> +     __u8                    apsta;
> +     __le16                  wctemp;
> +     __le16                  cctemp;
> +     __le16                  mtfa;
> +     __le32                  hmpre;
> +     __le32                  hmmin;
> +     __u8                    tnvmcap[16];
> +     __u8                    unvmcap[16];
> +     __le32                  rpmbs;
> +     __le16                  edstt;
> +     __u8                    dsto;
> +     __u8                    fwug;
> +     __le16                  kas;
> +     __le16                  hctma;
> +     __le16                  mntmt;
> +     __le16                  mxtmt;
> +     __le32                  sanicap;
> +     __le32                  hmminds;
> +     __le16                  hmmaxd;
> +     __u8                    rsvd338[4];
> +     __u8                    anatt;
> +     __u8                    anacap;
> +     __le32                  anagrpmax;
> +     __le32                  nanagrpid;
> +     __u8                    rsvd352[160];
> +     __u8                    sqes;
> +     __u8                    cqes;
> +     __le16                  maxcmd;
> +     __le32                  nn;
> +     __le16                  oncs;
> +     __le16                  fuses;
> +     __u8                    fna;
> +     __u8                    vwc;
> +     __le16                  awun;
> +     __le16                  awupf;
> +     __u8                    nvscc;
> +     __u8                    nwpc;
> +     __le16                  acwu;
> +     __u8                    rsvd534[2];
> +     __le32                  sgls;
> +     __le32                  mnan;
> +     __u8                    rsvd544[224];
> +     char                    subnqn[256];
> +     __u8                    rsvd1024[768];
> +     __le32                  ioccsz;
> +     __le32                  iorcsz;
> +     __le16                  icdoff;
> +     __u8                    ctrattr;
> +     __u8                    msdbd;
> +     __u8                    rsvd1804[244];
> +     struct nvme_id_power_state      psd[32];
> +     __u8                    vs[1024];
> +};
> +/* nvme id ctrl end */
> +
> +/* nvme id ns start */
> +struct nvme_lbaf {
> +     __le16                  ms;
> +     __u8                    ds;
> +     __u8                    rp;
> +};
> +
> +struct nvme_id_ns {
> +     __le64                  nsze;
> +     __le64                  ncap;
> +     __le64                  nuse;
> +     __u8                    nsfeat;
> +     __u8                    nlbaf;
> +     __u8                    flbas;
> +     __u8                    mc;
> +     __u8                    dpc;
> +     __u8                    dps;
> +     __u8                    nmic;
> +     __u8                    rescap;
> +     __u8                    fpi;
> +     __u8                    rsvd33;
> +     __le16                  nawun;
> +     __le16                  nawupf;
> +     __le16                  nacwu;
> +     __le16                  nabsn;
> +     __le16                  nabo;
> +     __le16                  nabspf;
> +     __le16                  noiob;
> +     __u8                    nvmcap[16];
> +     __u8                    rsvd64[28];
> +     __le32                  anagrpid;
> +     __u8                    rsvd96[3];
> +     __u8                    nsattr;
> +     __u8                    rsvd100[4];
> +     __u8                    nguid[16];
> +     __u8                    eui64[8];
> +     struct nvme_lbaf        lbaf[16];
> +     __u8                    rsvd192[192];
> +     __u8                    vs[3712];
> +};
> +/* nvme id ns end */
> +
> +/* nvme ana start */
> +enum nvme_ana_state {
> +     NVME_ANA_OPTIMIZED              = 0x01,
> +     NVME_ANA_NONOPTIMIZED           = 0x02,
> +     NVME_ANA_INACCESSIBLE           = 0x03,
> +     NVME_ANA_PERSISTENT_LOSS        = 0x04,
> +     NVME_ANA_CHANGE                 = 0x0f,
> +     NVME_ANA_RESERVED               = 0x05,
> +};
> +
> +struct nvme_ana_rsp_hdr {
> +     __le64  chgcnt;
> +     __le16  ngrps;
> +     __le16  rsvd10[3];
> +};
> +
> +struct nvme_ana_group_desc {
> +     __le32  grpid;
> +     __le32  nnsids;
> +     __le64  chgcnt;
> +     __u8    state;
> +     __u8    rsvd17[15];
> +     __le32  nsids[];
> +};
> +
> +/* flag for the log specific field of the ANA log */
> +#define NVME_ANA_LOG_RGO     (1 << 0)
> +
> +/* nvme ana end */
> +
> +#endif
> diff --git a/multipath/multipath.conf.5 b/multipath/multipath.conf.5
> index 6333366..c5b2fb6 100644
> --- a/multipath/multipath.conf.5
> +++ b/multipath/multipath.conf.5
> @@ -334,6 +334,10 @@ priority provided as argument. Requires
> prio_args keyword.
>  Generate the path priority based on a latency algorithm.
>  Requires prio_args keyword.
>  .TP
> +.I ana
> +(Hardware-dependent)
> +Generate the path priority based on the NVMe ANA settings.
> +.TP
>  .I datacore
>  (Hardware-dependent)
>  Generate the path priority for some DataCore storage arrays.
> Requires prio_args
> @@ -1391,6 +1395,10 @@ Active/Standby mode exclusively.
>  .I 1 alua
>  (Hardware-dependent)
>  Hardware handler for SCSI-3 ALUA compatible arrays.
> +.TP
> +.I 1 ana
> +(Hardware-dependent)
> +Hardware handler for NVMe ANA compatible arrays.

No. hardware handlers are for SCSI only.

Regards,
Martin

-- 
Dr. Martin Wilck <mwi...@suse.com>, Tel. +49 (0)911 74053 2107
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)


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