multipath-tools

h1. Wiki

File source:libmultipath/print.c:

<pre><code class="c">

static int

snprint_hcil (char * buff, size_t len, struct path * pp)

{

        if (pp->sg_id.host_no < 0)

                return snprintf(buff, len, "#:#:#:#");

        return snprintf(buff, len, "%i:%i:%i:%i",

                        pp->sg_id.host_no,

                        pp->sg_id.channel,

                        pp->sg_id.scsi_id,

                        pp->sg_id.lun);

}

</code></pre>

hcil == host channel ID LUN

definiert inf @struct path pp@, siehe 

file source:libmultipath/structs.h:

<pre><code class="c">

struct sg_id {

        int host_no;

        int channel;

        int scsi_id;

        int lun;

        short h_cmd_per_lun;

        short d_queue_depth;

        int unused1;

        int unused2;

};

struct path {

        char dev[FILE_NAME_SIZE];

        char dev_t[BLK_DEV_SIZE];

        struct scsi_idlun scsi_id;

        struct sg_id sg_id;

        char wwid[WWID_SIZE];

        char vendor_id[SCSI_VENDOR_SIZE];

        char product_id[SCSI_PRODUCT_SIZE];

        char rev[SCSI_REV_SIZE];

        char serial[SERIAL_SIZE];

        char tgt_node_name[NODE_NAME_SIZE];

        unsigned long long size;

        unsigned int checkint;

        unsigned int tick;

        int bus;

        int state;

        int dmstate;

        int failcount;

        int priority;

        int pgindex;

        char * getuid;

        char * getprio;

        int getprio_selected;

        struct checker checker;

        struct multipath * mpp;

        int fd;

        /* configlet pointers */

        struct hwentry * hwe;

};

</code></pre>

Befuellt wird @sg_id@ in file source:libmultipath/discovery.c:

<pre><code class="c">

static int

scsi_sysfs_pathinfo (struct path * pp)

{

...

        /*

         * host / bus / target / lun

         */

        if(safe_sprintf(attr_path, "%s/block/%s/device",

                        sysfs_path, pp->dev)) {

                condlog(0, "attr_path too small");

                return 1;

        }

        if (0 > sysfs_get_link(attr_path, attr_buff, sizeof(attr_buff)))

                return 1;

        basename(attr_buff, attr_path);

        sscanf(attr_path, "%i:%i:%i:%i",

                        &pp->sg_id.host_no,

                        &pp->sg_id.channel,

                        &pp->sg_id.scsi_id,

                        &pp->sg_id.lun);

...

        /*

         * target node name

         */

        if(safe_sprintf(attr_path,

                        "%s/class/fc_transport/target%i:%i:%i/node_name",

                        sysfs_path,

                        pp->sg_id.host_no,

                        pp->sg_id.channel,

                        pp->sg_id.scsi_id)) { ... }

...

}

</code></pre>

basename() ist keine libc Funktion, sie ist in util.c definiert und kopiert string1 ab dem letzten Slash auf string2 um.

Interessant auch das File source:libmultipath/hwtable.c#L925:

<pre><code class="c">

        /*

         * NETAPP controller family

         *

         * Maintainer : Dave Wysochanski

         * Mail : davidw@netapp.com

         */

        {

                .vendor        = "NETAPP",

                .product       = "LUN.*",

                .getuid        = DEFAULT_GETUID,

                .getprio       = "/sbin/mpath_prio_netapp /dev/%n",

                .features      = "1 queue_if_no_path",

                .hwhandler     = DEFAULT_HWHANDLER,

                .selector      = DEFAULT_SELECTOR,

                .pgpolicy      = GROUP_BY_PRIO,

                .pgfailback    = -FAILBACK_IMMEDIATE,

                .rr_weight     = RR_WEIGHT_NONE,

                .no_path_retry = NO_PATH_RETRY_UNDEF,

                .minio         = 128,

                .checker_name  = READSECTOR0,

        },

</pre>