policy: support devices with multiple paths.

As new releases of Linux some time change the name of
a path, some distros keep "legacy" names as well.  This
is useful, but confuses mdadm which assumes each device has
precisely one path.

So change this assumption:  allow a disk to have several
paths, and allow any to match when looking for a policy
which matches a disk.

Reported-and-tested-by: Mariusz Tkaczyk <mariusz.tkaczyk@intel.com>
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>

diff --git a/Incremental.c b/Incremental.c
index a4ff7d4bd22d5d8e039bdbe8987406badd60733c..d4d3c353560d8fb4946c8fad1b0840a0de82e0dd 100644 (file)
--- a/Incremental.c
+++ b/Incremental.c
@@ -1080,6 +1080,7 @@ static int partition_try_spare(char *devname, int *dfdp, struct dev_policy *pol,
                struct supertype *st2 = NULL;
                char *devname = NULL;
                unsigned long long devsectors;
+               char *pathlist[2];
 
                if (de->d_ino == 0 || de->d_name[0] == '.' ||
                    (de->d_type != DT_LNK && de->d_type != DT_UNKNOWN))
@@ -1094,7 +1095,9 @@ static int partition_try_spare(char *devname, int *dfdp, struct dev_policy *pol,
                        /* This is a partition - skip it */
                        goto next;
 
-               pol2 = path_policy(de->d_name, type_disk);
+               pathlist[0] = de->d_name;
+               pathlist[1] = NULL;
+               pol2 = path_policy(pathlist, type_disk);
 
                domain_merge(&domlist, pol2, st ? st->ss->name : NULL);
                if (domain_test(domlist, pol, st ? st->ss->name : NULL) != 1)

diff --git a/mdadm.h b/mdadm.h
index 387e681aa4edb1fe2ea90c0c7fb15865aee66b64..705bd9b53b3ae28e9cd403640a81e4705d4d467e 100644 (file)
--- a/mdadm.h
+++ b/mdadm.h
@@ -1247,7 +1247,7 @@ extern void policyline(char *line, char *type);
 extern void policy_add(char *type, ...);
 extern void policy_free(void);
 
-extern struct dev_policy *path_policy(char *path, char *type);
+extern struct dev_policy *path_policy(char **paths, char *type);
 extern struct dev_policy *disk_policy(struct mdinfo *disk);
 extern struct dev_policy *devid_policy(int devid);
 extern void dev_policy_free(struct dev_policy *p);

diff --git a/policy.c b/policy.c
index 258f39317951cece91d44997269dc9b045be087e..fa67d5594c043ccd1fb20ade770d297a8f33dcda 100644 (file)
--- a/policy.c
+++ b/policy.c
@@ -189,15 +189,17 @@ struct dev_policy *pol_find(struct dev_policy *pol, char *name)
        return pol;
 }
 
-static char *disk_path(struct mdinfo *disk)
+static char **disk_paths(struct mdinfo *disk)
 {
        struct stat stb;
        int prefix_len;
        DIR *by_path;
        char symlink[PATH_MAX] = "/dev/disk/by-path/";
-       char nm[PATH_MAX];
+       char **paths;
+       int cnt = 0;
        struct dirent *ent;
-       int rv;
+
+       paths = xmalloc(sizeof(*paths) * (cnt+1));
 
        by_path = opendir(symlink);
        if (by_path) {
@@ -214,22 +216,13 @@ static char *disk_path(struct mdinfo *disk)
                                continue;
                        if (stb.st_rdev != makedev(disk->disk.major, disk->disk.minor))
                                continue;
-                       closedir(by_path);
-                       return xstrdup(ent->d_name);
+                       paths[cnt++] = xstrdup(ent->d_name);
+                       paths = xrealloc(paths, sizeof(*paths) * (cnt+1));
                }
                closedir(by_path);
        }
-       /* A NULL path isn't really acceptable - use the devname.. */
-       sprintf(symlink, "/sys/dev/block/%d:%d", disk->disk.major, disk->disk.minor);
-       rv = readlink(symlink, nm, sizeof(nm)-1);
-       if (rv > 0) {
-               char *dname;
-               nm[rv] = 0;
-               dname = strrchr(nm, '/');
-               if (dname)
-                       return xstrdup(dname + 1);
-       }
-       return xstrdup("unknown");
+       paths[cnt] = NULL;
+       return paths;
 }
 
 char type_part[] = "part";
@@ -246,18 +239,53 @@ static char *disk_type(struct mdinfo *disk)
                return type_disk;
 }
 
-static int pol_match(struct rule *rule, char *path, char *type)
+static int path_has_part(char *path, char **part)
+{
+       /* check if path ends with "-partNN" and
+        * if it does, place a pointer to "-pathNN"
+        * in 'part'.
+        */
+       int l;
+       if (!path)
+               return 0;
+       l = strlen(path);
+       while (l > 1 && isdigit(path[l-1]))
+               l--;
+       if (l < 5 || strncmp(path+l-5, "-part", 5) != 0)
+               return 0;
+       *part = path+l-5;
+       return 1;
+}
+
+static int pol_match(struct rule *rule, char **paths, char *type, char **part)
 {
-       /* check if this rule matches on path and type */
+       /* Check if this rule matches on any path and type.
+        * If 'part' is not NULL, then 'path' must end in -partN, which
+        * we ignore for matching, and return in *part on success.
+        */
        int pathok = 0; /* 0 == no path, 1 == match, -1 == no match yet */
        int typeok = 0;
 
-       while (rule) {
+       for (; rule; rule = rule->next) {
                if (rule->name == rule_path) {
+                       char *p;
+                       int i;
                        if (pathok == 0)
                                pathok = -1;
-                       if (path && fnmatch(rule->value, path, 0) == 0)
-                               pathok = 1;
+                       if (!paths)
+                               continue;
+                       for (i = 0; paths[i]; i++) {
+                               if (part) {
+                                       if (!path_has_part(paths[i], &p))
+                                               continue;
+                                       *p = '\0';
+                                       *part = p+1;
+                               }
+                               if (fnmatch(rule->value, paths[i], 0) == 0)
+                                       pathok = 1;
+                               if (part)
+                                       *p = '-';
+                       }
                }
                if (rule->name == rule_type) {
                        if (typeok == 0)
@@ -265,7 +293,6 @@ static int pol_match(struct rule *rule, char *path, char *type)
                        if (type && strcmp(rule->value, type) == 0)
                                typeok = 1;
                }
-               rule = rule->next;
        }
        return pathok >= 0 && typeok >= 0;
 }
@@ -286,24 +313,6 @@ static void pol_merge(struct dev_policy **pol, struct rule *rule)
                        pol_new(pol, r->name, r->value, metadata);
 }
 
-static int path_has_part(char *path, char **part)
-{
-       /* check if path ends with "-partNN" and
-        * if it does, place a pointer to "-pathNN"
-        * in 'part'.
-        */
-       int l;
-       if (!path)
-               return 0;
-       l = strlen(path);
-       while (l > 1 && isdigit(path[l-1]))
-               l--;
-       if (l < 5 || strncmp(path+l-5, "-part", 5) != 0)
-               return 0;
-       *part = path+l-5;
-       return 1;
-}
-
 static void pol_merge_part(struct dev_policy **pol, struct rule *rule, char *part)
 {
        /* copy any name assignments from rule into pol, appending
@@ -352,7 +361,7 @@ static int config_rules_has_path = 0;
  * path_policy() gathers policy information for the
  * disk described in the given a 'path' and a 'type'.
  */
-struct dev_policy *path_policy(char *path, char *type)
+struct dev_policy *path_policy(char **paths, char *type)
 {
        struct pol_rule *rules;
        struct dev_policy *pol = NULL;
@@ -361,27 +370,24 @@ struct dev_policy *path_policy(char *path, char *type)
        rules = config_rules;
 
        while (rules) {
-               char *part;
+               char *part = NULL;
                if (rules->type == rule_policy)
-                       if (pol_match(rules->rule, path, type))
+                       if (pol_match(rules->rule, paths, type, NULL))
                                pol_merge(&pol, rules->rule);
                if (rules->type == rule_part && strcmp(type, type_part) == 0)
-                       if (path_has_part(path, &part)) {
-                               *part = 0;
-                               if (pol_match(rules->rule, path, type_disk))
-                                       pol_merge_part(&pol, rules->rule, part+1);
-                               *part = '-';
-                       }
+                       if (pol_match(rules->rule, paths, type_disk, &part))
+                                       pol_merge_part(&pol, rules->rule, part);
                rules = rules->next;
        }
 
        /* Now add any metadata-specific internal knowledge
         * about this path
         */
-       for (i=0; path && superlist[i]; i++)
+       for (i=0; paths[0] && superlist[i]; i++)
                if (superlist[i]->get_disk_controller_domain) {
                        const char *d =
-                               superlist[i]->get_disk_controller_domain(path);
+                               superlist[i]->get_disk_controller_domain(
+                                       paths[0]);
                        if (d)
                                pol_new(&pol, pol_domain, d, superlist[i]->name);
                }
@@ -400,22 +406,34 @@ void pol_add(struct dev_policy **pol,
        pol_dedup(*pol);
 }
 
+static void free_paths(char **paths)
+{
+       int i;
+
+       if (!paths)
+               return;
+
+       for (i = 0; paths[i]; i++)
+               free(paths[i]);
+       free(paths);
+}
+
 /*
  * disk_policy() gathers policy information for the
  * disk described in the given mdinfo (disk.{major,minor}).
  */
 struct dev_policy *disk_policy(struct mdinfo *disk)
 {
-       char *path = NULL;
+       char **paths = NULL;
        char *type = disk_type(disk);
        struct dev_policy *pol = NULL;
 
        if (config_rules_has_path)
-               path = disk_path(disk);
+               paths = disk_paths(disk);
 
-       pol = path_policy(path, type);
+       pol = path_policy(paths, type);
 
-       free(path);
+       free_paths(paths);
        return pol;
 }
 
@@ -756,27 +774,26 @@ int policy_check_path(struct mdinfo *disk, struct map_ent *array)
 {
        char path[PATH_MAX];
        FILE *f = NULL;
-       char *id_path = disk_path(disk);
-       int rv;
+       char **id_paths = disk_paths(disk);
+       int i;
+       int rv = 0;
 
-       if (!id_path)
-               return 0;
+       for (i = 0; id_paths[i]; i++) {
+               snprintf(path, PATH_MAX, FAILED_SLOTS_DIR "/%s", id_paths[i]);
+               f = fopen(path, "r");
+               if (!f)
+                       continue;
 
-       snprintf(path, PATH_MAX, FAILED_SLOTS_DIR "/%s", id_path);
-       f = fopen(path, "r");
-       if (!f) {
-               free(id_path);
-               return 0;
+               rv = fscanf(f, " %s %x:%x:%x:%x\n",
+                           array->metadata,
+                           array->uuid,
+                           array->uuid+1,
+                           array->uuid+2,
+                           array->uuid+3);
+               fclose(f);
+               break;
        }
-
-       rv = fscanf(f, " %s %x:%x:%x:%x\n",
-                   array->metadata,
-                   array->uuid,
-                   array->uuid+1,
-                   array->uuid+2,
-                   array->uuid+3);
-       fclose(f);
-       free(id_path);
+       free_paths(id_paths);
        return rv == 5;
 }