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Re: [dm-devel] [PATCH] [RFC] [PATCH] Add alias_prefix to get multipath names based on storage type



I'd rather have others give their feeling on the usefullness of this feature. My own opinion is that user_friendly_names are for people who don't care about naming, alias for those who care. This per-hardware prefix would fill a quite narrow gap in-between ... But some may have more enthusiast feeling, which will matter.

At least it doesn't change the current behaviour by default.

Best regards,
cvaroqui

----- Message d'origine -----
> Any comments??
>
> Malahal Naineni [malahal us ibm com] wrote:
> > The current multipath tools use "mpath" prefix for all LUNs when
> > user_friendly_names is set. It would be nice if the names are generated
> > based on the storage subsystem. For example, all EMC LUNs would be
> > named emc_a, emc_b, elm_c etc., and all IBM's SVC LUNs would be named
> > svc_a, svc_b, svc_c. This patch attempts to do that using only
> > multipath.conf. Patches can be added to the internal hardware table,
> > if needed.
> >
> > Signed-off-by: Malahal Naineni (malahal us ibm com)
> >
> > diff -r 49b7dc2c9d46 -r b4d519b4bbc6 libmultipath/alias.c
> > --- a/libmultipath/alias.c    Tue Jun 15 17:23:49 2010 -0700
> > +++ b/libmultipath/alias.c    Tue Jun 22 19:25:24 2010 -0700
> > @@ -180,34 +180,35 @@ fail:
> > }
> >
> > static int
> > -format_devname(char *name, int id, int len)
> > +format_devname(char *name, int id, int len, char *prefix)
> > {
> >     int pos;
> > +    int prefix_len = strlen(prefix);
> >
> >     memset(name,0, len);
> > -    strcpy(name,"mpath");
> > -    for (pos = len - 1; pos >= 5; pos--) {
> > +    strcpy(name, prefix);
> > +    for (pos = len - 1; pos >= prefix_len; pos--) {
> >         name[pos] = 'a' + id % 26;
> >         if (id < 26)
> >             break;
> >         id /= 26;
> >         id--;
> >     }
> > -    memmove(name + 5, name + pos, len - pos);
> > -    name[5 + len - pos] = '\0';
> > -    return (5 + len - pos);
> > +    memmove(name + prefix_len, name + pos, len - pos);
> > +    name[prefix_len + len - pos] = '\0';
> > +    return (prefix_len + len - pos);
> > }
> >
> > static int
> > -scan_devname(char *alias)
> > +scan_devname(char *alias, char *prefix)
> > {
> >     char *c;
> >     int i, n = 0;
> >
> > -    if (strncmp(alias, "mpath", 5))
> > +    if (!prefix || strncmp(alias, prefix, strlen(prefix)))
> >         return -1;
> >
> > -    c = alias + 5;
> > +    c = alias + strlen(prefix);
> >     while (*c != '\0' && *c != ' ' && *c != '\t') {
> >         i = *c - 'a';
> >         n = ( n * 26 ) + i;
> > @@ -221,7 +222,7 @@ scan_devname(char *alias)
> > }
> >
> > static int
> > -lookup_binding(FILE *f, char *map_wwid, char **map_alias)
> > +lookup_binding(FILE *f, char *map_wwid, char **map_alias, char
> > *prefix) {
> >     char buf[LINE_MAX];
> >     unsigned int line_nr = 0;
> > @@ -240,7 +241,7 @@ lookup_binding(FILE *f, char *map_wwid,
> >         alias = strtok(buf, " \t");
> >         if (!alias) /* blank line */
> >             continue;
> > -        curr_id = scan_devname(alias);
> > +        curr_id = scan_devname(alias, prefix);
> >         if (curr_id >= id)
> >             id = curr_id + 1;
> >         wwid = strtok(NULL, "");
> > @@ -284,7 +285,7 @@ rlookup_binding(FILE *f, char **map_wwid
> >         alias = strtok(buf, " \t");
> >         if (!alias) /* blank line */
> >             continue;
> > -        curr_id = scan_devname(alias);
> > +        curr_id = scan_devname(alias, NULL); /* TBD: Why this call? */
> >         if (curr_id >= id)
> >             id = curr_id + 1;
> >         wwid = strtok(NULL, " \t");
> > @@ -309,7 +310,7 @@ rlookup_binding(FILE *f, char **map_wwid
> > }
> >
> > static char *
> > -allocate_binding(int fd, char *wwid, int id)
> > +allocate_binding(int fd, char *wwid, int id, char *prefix)
> > {
> >     char buf[LINE_MAX];
> >     off_t offset;
> > @@ -321,7 +322,7 @@ allocate_binding(int fd, char *wwid, int
> >         return NULL;
> >     }
> >
> > -    i = format_devname(buf, id, LINE_MAX);
> > +    i = format_devname(buf, id, LINE_MAX, prefix);
> >     c = buf + i;
> >     snprintf(c,LINE_MAX - i, " %s\n", wwid);
> >     buf[LINE_MAX - 1] = '\0';
> > @@ -352,7 +353,7 @@ allocate_binding(int fd, char *wwid, int
> > }
> >
> > char *
> > -get_user_friendly_alias(char *wwid, char *file)
> > +get_user_friendly_alias(char *wwid, char *file, char *prefix)
> > {
> >     char *alias;
> >     int fd, scan_fd, id;
> > @@ -385,7 +386,7 @@ get_user_friendly_alias(char *wwid, char
> >         return NULL;
> >     }
> >
> > -    id = lookup_binding(f, wwid, &alias);
> > +    id = lookup_binding(f, wwid, &alias, prefix);
> >     if (id < 0) {
> >         fclose(f);
> >         close(scan_fd);
> > @@ -394,7 +395,7 @@ get_user_friendly_alias(char *wwid, char
> >     }
> >
> >     if (!alias && can_write)
> > -        alias = allocate_binding(fd, wwid, id);
> > +        alias = allocate_binding(fd, wwid, id, prefix);
> >
> >     fclose(f);
> >     close(scan_fd);
> > diff -r 49b7dc2c9d46 -r b4d519b4bbc6 libmultipath/alias.h
> > --- a/libmultipath/alias.h    Tue Jun 15 17:23:49 2010 -0700
> > +++ b/libmultipath/alias.h    Tue Jun 22 19:25:24 2010 -0700
> > @@ -8,5 +8,5 @@
> > "# alias wwid\n" \
> > "#\n"
> >
> > -char *get_user_friendly_alias(char *wwid, char *file);
> > +char *get_user_friendly_alias(char *wwid, char *file, char *prefix);
> > char *get_user_friendly_wwid(char *alias, char *file);
> > diff -r 49b7dc2c9d46 -r b4d519b4bbc6 libmultipath/config.c
> > --- a/libmultipath/config.c    Tue Jun 15 17:23:49 2010 -0700
> > +++ b/libmultipath/config.c    Tue Jun 22 19:25:24 2010 -0700
> > @@ -158,6 +158,9 @@ free_hwe (struct hwentry * hwe)
> >     if (hwe->prio_args)
> >         FREE(hwe->prio_args);
> >
> > +    if (hwe->alias_prefix)
> > +        FREE(hwe->alias_prefix);
> > +
> >     if (hwe->bl_product)
> >         FREE(hwe->bl_product);
> >
> > @@ -282,6 +285,7 @@ merge_hwe (struct hwentry * hwe1, struct
> >     merge_str(checker_name);
> >     merge_str(prio_name);
> >     merge_str(prio_args);
> > +    merge_str(alias_prefix);
> >     merge_str(bl_product);
> >     merge_num(pgpolicy);
> >     merge_num(pgfailback);
> > @@ -333,6 +337,9 @@ store_hwe (vector hwtable, struct hwentr
> >     if (dhwe->prio_args && !(hwe->prio_args =
> > set_param_str(dhwe->prio_args)))        goto out;
> >
> > +    if (dhwe->alias_prefix && !(hwe->alias_prefix =
> > set_param_str(dhwe->alias_prefix))) +        goto out;
> > +
> >     hwe->pgpolicy = dhwe->pgpolicy;
> >     hwe->pgfailback = dhwe->pgfailback;
> >     hwe->rr_weight = dhwe->rr_weight;
> > @@ -409,6 +416,9 @@ free_config (struct config * conf)
> >     if (conf->prio_name)
> >         FREE(conf->prio_name);
> >
> > +    if (conf->alias_prefix)
> > +        FREE(conf->alias_prefix);
> > +
> >     if (conf->prio_args)
> >         FREE(conf->prio_args);
> >
> > diff -r 49b7dc2c9d46 -r b4d519b4bbc6 libmultipath/config.h
> > --- a/libmultipath/config.h    Tue Jun 15 17:23:49 2010 -0700
> > +++ b/libmultipath/config.h    Tue Jun 22 19:25:24 2010 -0700
> > @@ -25,6 +25,7 @@ struct hwentry {
> >     char * checker_name;
> >     char * prio_name;
> >     char * prio_args;
> > +    char * alias_prefix;
> >
> >     int pgpolicy;
> >     int pgfailback;
> > @@ -99,6 +100,7 @@ struct config {
> >     char * prio_name;
> >     char * prio_args;
> >     char * checker_name;
> > +    char * alias_prefix;
> >
> >     vector keywords;
> >     vector mptable;
> > diff -r 49b7dc2c9d46 -r b4d519b4bbc6 libmultipath/defaults.h
> > --- a/libmultipath/defaults.h    Tue Jun 15 17:23:49 2010 -0700
> > +++ b/libmultipath/defaults.h    Tue Jun 22 19:25:24 2010 -0700
> > @@ -2,6 +2,7 @@
> > #define DEFAULT_UDEVDIR        "/dev"
> > #define DEFAULT_MULTIPATHDIR    "/" LIB_STRING "/multipath"
> > #define DEFAULT_SELECTOR    "round-robin 0"
> > +#define DEFAULT_ALIAS_PREFIX    "mpath"
> > #define DEFAULT_FEATURES    "0"
> > #define DEFAULT_HWHANDLER    "0"
> > #define DEFAULT_MINIO        1000
> > diff -r 49b7dc2c9d46 -r b4d519b4bbc6 libmultipath/dict.c
> > --- a/libmultipath/dict.c    Tue Jun 15 17:23:49 2010 -0700
> > +++ b/libmultipath/dict.c    Tue Jun 22 19:25:24 2010 -0700
> > @@ -148,6 +148,17 @@ def_prio_handler(vector strvec)
> > }
> >
> > static int
> > +def_alias_prefix_handler(vector strvec)
> > +{
> > +    conf->alias_prefix = set_value(strvec);
> > +
> > +    if (!conf->alias_prefix)
> > +        return 1;
> > +
> > +    return 0;
> > +}
> > +
> > +static int
> > def_prio_args_handler(vector strvec)
> > {
> >     conf->prio_args = set_value(strvec);
> > @@ -831,6 +842,22 @@ hw_prio_handler(vector strvec)
> > }
> >
> > static int
> > +hw_alias_prefix_handler(vector strvec)
> > +{
> > +    struct hwentry * hwe = VECTOR_LAST_SLOT(conf->hwtable);
> > +
> > +    if (!hwe)
> > +        return 1;
> > +
> > +    hwe->alias_prefix = set_value(strvec);
> > +
> > +    if (!hwe->alias_prefix)
> > +        return 1;
> > +
> > +    return 0;
> > +}
> > +
> > +static int
> > hw_prio_args_handler(vector strvec)
> > {
> >     struct hwentry * hwe = VECTOR_LAST_SLOT(conf->hwtable);
> > @@ -1580,6 +1607,19 @@ snprint_hw_prio (char * buff, int len, v
> > }
> >
> > static int
> > +snprint_hw_alias_prefix (char * buff, int len, void * data)
> > +{
> > +    struct hwentry * hwe = (struct hwentry *)data;
> > +
> > +    if (!hwe->alias_prefix || (strlen(hwe->alias_prefix) == 0))
> > +        return 0;
> > +    if (conf->alias_prefix && !strcmp(hwe->alias_prefix,
> > conf->alias_prefix)) +        return 0;
> > +
> > +    return snprintf(buff, len, "%s", hwe->alias_prefix);
> > +}
> > +
> > +static int
> > snprint_hw_prio_args (char * buff, int len, void * data)
> > {
> >     struct hwentry * hwe = (struct hwentry *)data;
> > @@ -2076,6 +2116,16 @@ snprint_def_user_friendly_names (char *
> > }
> >
> > static int
> > +snprint_def_alias_prefix (char * buff, int len, void * data)
> > +{
> > +    if (!conf->alias_prefix)
> > +        return 0;
> > +    if (!strcmp(conf->alias_prefix, DEFAULT_ALIAS_PREFIX))
> > +        return 0;
> > +    return snprintf(buff, len, conf->alias_prefix);
> > +}
> > +
> > +static int
> > snprint_ble_simple (char * buff, int len, void * data)
> > {
> >     struct blentry * ble = (struct blentry *)data;
> > @@ -2117,6 +2167,7 @@ init_keywords(void)
> >     install_keyword("features", &def_features_handler,
> > &snprint_def_features);    install_keyword("path_checker",
> > &def_path_checker_handler, &snprint_def_path_checker);
> >     install_keyword("checker", &def_path_checker_handler,
> > &snprint_def_path_checker); +    install_keyword("alias_prefix",
> > &def_alias_prefix_handler, &snprint_def_alias_prefix);
> >     install_keyword("failback", &default_failback_handler,
> > &snprint_def_failback);    install_keyword("rr_min_io",
> > &def_minio_handler, &snprint_def_rr_min_io);
> >     install_keyword("max_fds", &max_fds_handler, &snprint_max_fds); @@
> > -2176,6 +2227,7 @@ init_keywords(void)
> >     install_keyword("path_selector", &hw_selector_handler,
> > &snprint_hw_selector);    install_keyword("path_checker",
> > &hw_path_checker_handler, &snprint_hw_path_checker);
> >     install_keyword("checker", &hw_path_checker_handler,
> > &snprint_hw_path_checker); +    install_keyword("alias_prefix",
> > &hw_alias_prefix_handler, &snprint_hw_alias_prefix);
> >     install_keyword("features", &hw_features_handler,
> > &snprint_hw_features);    install_keyword("hardware_handler",
> > &hw_handler_handler, &snprint_hw_hardware_handler);
> >     install_keyword("prio", &hw_prio_handler, &snprint_hw_prio); diff -r
> > 49b7dc2c9d46 -r b4d519b4bbc6 libmultipath/propsel.c ---
> > a/libmultipath/propsel.c    Tue Jun 15 17:23:49 2010 -0700 +++
> > b/libmultipath/propsel.c    Tue Jun 22 19:25:24 2010 -0700 @@ -215,6
> > +215,26 @@ select_selector (struct multipath * mp)    return 0; }
> >
> > +static void
> > +select_alias_prefix (struct multipath * mp)
> > +{
> > +    if (mp->hwe && mp->hwe->alias_prefix) {
> > +        mp->alias_prefix = mp->hwe->alias_prefix;
> > +        condlog(3, "%s: alias_prefix = %s (controller setting)",
> > +            mp->wwid, mp->alias_prefix);
> > +        return;
> > +    }
> > +    if (conf->alias_prefix) {
> > +        mp->alias_prefix = conf->alias_prefix;
> > +        condlog(3, "%s: alias_prefix = %s (config file default)",
> > +            mp->wwid, mp->alias_prefix);
> > +        return;
> > +    }
> > +    mp->alias_prefix = set_default(DEFAULT_ALIAS_PREFIX);
> > +    condlog(3, "%s: alias_prefix = %s (internal default)",
> > +        mp->wwid, mp->alias_prefix);
> > +}
> > +
> > extern int
> > select_alias (struct multipath * mp)
> > {
> > @@ -222,9 +242,11 @@ select_alias (struct multipath * mp)
> >         mp->alias = mp->mpe->alias;
> >     else {
> >         mp->alias = NULL;
> > -        if (conf->user_friendly_names)
> > +        if (conf->user_friendly_names) {
> > +            select_alias_prefix(mp);
> >             mp->alias = get_user_friendly_alias(mp->wwid,
> > -                    conf->bindings_file);
> > +                    conf->bindings_file, mp->alias_prefix);
> > +        }
> >         if (mp->alias == NULL){
> >             char *alias;
> >             if ((alias = MALLOC(WWID_SIZE)) != NULL){
> > diff -r 49b7dc2c9d46 -r b4d519b4bbc6 libmultipath/structs.h
> > --- a/libmultipath/structs.h    Tue Jun 15 17:23:49 2010 -0700
> > +++ b/libmultipath/structs.h    Tue Jun 22 19:25:24 2010 -0700
> > @@ -186,6 +186,7 @@ struct multipath {
> >
> >     /* configlet pointers */
> >     char * alias;
> > +    char * alias_prefix;
> >     char * selector;
> >     char * features;
> >     char * hwhandler;
> >
> > --
> > dm-devel mailing list
> > dm-devel redhat com
> > https://www.redhat.com/mailman/listinfo/dm-devel
>
> --
> dm-devel mailing list
> dm-devel redhat com
> https://www.redhat.com/mailman/listinfo/dm-devel


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