mapfile.c

   1 /*
   2  * mapfile - manage /var/run/mdadm.map. Part of:
   3  * mdadm - manage Linux "md" devices aka RAID arrays.
   4  *
   5  * Copyright (C) 2006-2009 Neil Brown <neilb@suse.de>
   6  *
   7  *
   8  *    This program is free software; you can redistribute it and/or modify
   9  *    it under the terms of the GNU General Public License as published by
  10  *    the Free Software Foundation; either version 2 of the License, or
  11  *    (at your option) any later version.
  12  *
  13  *    This program is distributed in the hope that it will be useful,
  14  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *    GNU General Public License for more details.
  17  *
  18  *    You should have received a copy of the GNU General Public License
  19  *    along with this program; if not, write to the Free Software
  20  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  *
  22  *    Author: Neil Brown
  23  *    Email: <neilb@suse.de>
  24  *    Paper: Neil Brown
  25  *           Novell Inc
  26  *           GPO Box Q1283
  27  *           QVB Post Office, NSW 1230
  28  *           Australia
  29  */
  30
  31 /* /var/run/mdadm.map is used to track arrays being created in --incremental
  32  * mode.  It particularly allows lookup from UUID to array device, but
  33  * also allows the array device name to be easily found.
  34  *
  35  * The map file is line based with space separated fields.  The fields are:
  36  *  Device id  -  mdX or mdpX  where X is a number.
  37  *  metadata   -  0.90 1.0 1.1 1.2 ddf ...
  38  *  UUID       -  uuid of the array
  39  *  path       -  path where device created: /dev/md/home
  40  *
  41  * The preferred location for the map file is /var/run/mdadm.map.
  42  * However /var/run may not exist or be writable in early boot.  And if
  43  * no-one has created /var/run/mdadm, we still want to survive.
  44  * So possible locations are:
  45  *   /var/run/mdadm/map  /var/run/mdadm.map  /lib/initrw/madam/map
  46  * The last can easily be change at compile to e.g. somewhere in /dev.
  47  * We read from the first one that exists and write to the first
  48  * one that we can.
  49  */
  50 #include        "mdadm.h"
  51 #include        <sys/file.h>
  52 #include        <ctype.h>
  53
  54 #define mapnames(base) { base, base ".new", base ".lock"}
  55 char *mapname[2][3] = {
  56         mapnames(MAP_DIR "/" MAP_FILE),
  57         mapnames("/var/run/mdadm.map")
  58 };
  59 char *mapdir[2] = { MAP_DIR, NULL };
  60
  61 int mapmode[3] = { O_RDONLY, O_RDWR|O_CREAT, O_RDWR|O_CREAT|O_TRUNC };
  62 char *mapsmode[3] = { "r", "w", "w"};
  63
  64 FILE *open_map(int modenum, int *choice)
  65 {
  66         int i;
  67
  68         for (i = 0 ; i < 2 ; i++) {
  69                 int fd;
  70                 if ((mapmode[modenum] & O_CREAT) && mapdir[i])
  71                         /* Attempt to create directory, don't worry about
  72                          * failure.
  73                          */
  74                         mkdir(mapdir[i], 0755);
  75                 fd = open(mapname[i][modenum], mapmode[modenum], 0600);
  76                 if (fd >= 0) {
  77                         *choice = i;
  78                         return fdopen(fd, mapsmode[modenum]);
  79                 }
  80         }
  81         return NULL;
  82 }
  83
  84 int map_write(struct map_ent *mel)
  85 {
  86         FILE *f;
  87         int err;
  88         int which;
  89
  90         f = open_map(1, &which);
  91
  92         if (!f)
  93                 return 0;
  94         for (; mel; mel = mel->next) {
  95                 if (mel->bad)
  96                         continue;
  97                 if (mel->devnum < 0)
  98                         fprintf(f, "mdp%d ", -1-mel->devnum);
  99                 else
 100                         fprintf(f, "md%d ", mel->devnum);
 101                 fprintf(f, "%s ", mel->metadata);
 102                 fprintf(f, "%08x:%08x:%08x:%08x ", mel->uuid[0],
 103                         mel->uuid[1], mel->uuid[2], mel->uuid[3]);
 104                 fprintf(f, "%s\n", mel->path?:"");
 105         }
 106         fflush(f);
 107         err = ferror(f);
 108         fclose(f);
 109         if (err) {
 110                 unlink(mapname[which][1]);
 111                 return 0;
 112         }
 113         return rename(mapname[which][1],
 114                       mapname[which][0]) == 0;
 115 }
 116
 117
 118 static FILE *lf = NULL;
 119 static int lwhich = 0;
 120 int map_lock(struct map_ent **melp)
 121 {
 122         if (lf == NULL) {
 123                 lf = open_map(2, &lwhich);
 124                 if (lf == NULL)
 125                         return -1;
 126                 if (flock(fileno(lf), LOCK_EX) != 0) {
 127                         fclose(lf);
 128                         lf = NULL;
 129                         return -1;
 130                 }
 131         }
 132         if (*melp)
 133                 map_free(*melp);
 134         map_read(melp);
 135         return 0;
 136 }
 137
 138 void map_unlock(struct map_ent **melp)
 139 {
 140         if (lf) {
 141                 flock(fileno(lf), LOCK_UN);
 142                 fclose(lf);
 143         }
 144         unlink(mapname[lwhich][2]);
 145         lf = NULL;
 146 }
 147
 148 void map_add(struct map_ent **melp,
 149             int devnum, char *metadata, int uuid[4], char *path)
 150 {
 151         struct map_ent *me = malloc(sizeof(*me));
 152
 153         me->devnum = devnum;
 154         strcpy(me->metadata, metadata);
 155         memcpy(me->uuid, uuid, 16);
 156         me->path = path ? strdup(path) : NULL;
 157         me->next = *melp;
 158         me->bad = 0;
 159         *melp = me;
 160 }
 161
 162 void map_read(struct map_ent **melp)
 163 {
 164         FILE *f;
 165         char buf[8192];
 166         char path[200];
 167         int devnum, uuid[4];
 168         char metadata[30];
 169         char nam[4];
 170         int which;
 171
 172         *melp = NULL;
 173
 174         f = open_map(0, &which);
 175         if (!f) {
 176                 RebuildMap();
 177                 f = open_map(0, &which);
 178         }
 179         if (!f)
 180                 return;
 181
 182         while (fgets(buf, sizeof(buf), f)) {
 183                 path[0] = 0;
 184                 if (sscanf(buf, " %3[mdp]%d %s %x:%x:%x:%x %200s",
 185                            nam, &devnum, metadata, uuid, uuid+1,
 186                            uuid+2, uuid+3, path) >= 7) {
 187                         if (strncmp(nam, "md", 2) != 0)
 188                                 continue;
 189                         if (nam[2] == 'p')
 190                                 devnum = -1 - devnum;
 191                         map_add(melp, devnum, metadata, uuid, path);
 192                 }
 193         }
 194         fclose(f);
 195 }
 196
 197 void map_free(struct map_ent *map)
 198 {
 199         while (map) {
 200                 struct map_ent *mp = map;
 201                 map = mp->next;
 202                 free(mp->path);
 203                 free(mp);
 204         }
 205 }
 206
 207 int map_update(struct map_ent **mpp, int devnum, char *metadata,
 208                int *uuid, char *path)
 209 {
 210         struct map_ent *map, *mp;
 211         int rv;
 212
 213         if (mpp && *mpp)
 214                 map = *mpp;
 215         else
 216                 map_read(&map);
 217
 218         for (mp = map ; mp ; mp=mp->next)
 219                 if (mp->devnum == devnum) {
 220                         strcpy(mp->metadata, metadata);
 221                         memcpy(mp->uuid, uuid, 16);
 222                         free(mp->path);
 223                         mp->path = path ? strdup(path) : NULL;
 224                         break;
 225                 }
 226         if (!mp)
 227                 map_add(&map, devnum, metadata, uuid, path);
 228         if (mpp)
 229                 *mpp = NULL;
 230         rv = map_write(map);
 231         map_free(map);
 232         return rv;
 233 }
 234
 235 void map_delete(struct map_ent **mapp, int devnum)
 236 {
 237         struct map_ent *mp;
 238
 239         if (*mapp == NULL)
 240                 map_read(mapp);
 241
 242         for (mp = *mapp; mp; mp = *mapp) {
 243                 if (mp->devnum == devnum) {
 244                         *mapp = mp->next;
 245                         free(mp->path);
 246                         free(mp);
 247                 } else
 248                         mapp = & mp->next;
 249         }
 250 }
 251
 252 void map_remove(struct map_ent **mapp, int devnum)
 253 {
 254         if (devnum == NoMdDev)
 255                 return;
 256
 257         map_delete(mapp, devnum);
 258         map_write(*mapp);
 259         map_free(*mapp);
 260 }
 261
 262 struct map_ent *map_by_uuid(struct map_ent **map, int uuid[4])
 263 {
 264         struct map_ent *mp;
 265         if (!*map)
 266                 map_read(map);
 267
 268         for (mp = *map ; mp ; mp = mp->next) {
 269                 if (memcmp(uuid, mp->uuid, 16) != 0)
 270                         continue;
 271                 if (!mddev_busy(mp->devnum)) {
 272                         mp->bad = 1;
 273                         continue;
 274                 }
 275                 return mp;
 276         }
 277         return NULL;
 278 }
 279
 280 struct map_ent *map_by_devnum(struct map_ent **map, int devnum)
 281 {
 282         struct map_ent *mp;
 283         if (!*map)
 284                 map_read(map);
 285
 286         for (mp = *map ; mp ; mp = mp->next) {
 287                 if (mp->devnum != devnum)
 288                         continue;
 289                 if (!mddev_busy(mp->devnum)) {
 290                         mp->bad = 1;
 291                         continue;
 292                 }
 293                 return mp;
 294         }
 295         return NULL;
 296 }
 297
 298 struct map_ent *map_by_name(struct map_ent **map, char *name)
 299 {
 300         struct map_ent *mp;
 301         if (!*map)
 302                 map_read(map);
 303
 304         for (mp = *map ; mp ; mp = mp->next) {
 305                 if (!mp->path)
 306                         continue;
 307                 if (strncmp(mp->path, "/dev/md/", 8) != 0)
 308                         continue;
 309                 if (strcmp(mp->path+8, name) != 0)
 310                         continue;
 311                 if (!mddev_busy(mp->devnum)) {
 312                         mp->bad = 1;
 313                         continue;
 314                 }
 315                 return mp;
 316         }
 317         return NULL;
 318 }
 319
 320 /* sets the proper subarray and container_dev according to the metadata
 321  * version super_by_fd does this automatically, this routine is meant as
 322  * a supplement for guess_super()
 323  */
 324 static void set_member_info(struct supertype *st, struct mdstat_ent *ent)
 325 {
 326
 327         st->subarray[0] = '\0';
 328
 329         if (ent->metadata_version == NULL ||
 330             strncmp(ent->metadata_version, "external:", 9) != 0)
 331                 return;
 332
 333         if (is_subarray(&ent->metadata_version[9])) {
 334                 char version[strlen(ent->metadata_version)+1];
 335                 char *subarray;
 336                 char *name = &version[10];
 337
 338                 strcpy(version, ent->metadata_version);
 339                 subarray = strrchr(version, '/');
 340                 name = &version[10];
 341
 342                 if (!subarray)
 343                         return;
 344                 *subarray++ = '\0';
 345
 346                 st->container_dev = devname2devnum(name);
 347                 strncpy(st->subarray, subarray, sizeof(st->subarray));
 348         }
 349 }
 350
 351 void RebuildMap(void)
 352 {
 353         struct mdstat_ent *mdstat = mdstat_read(0, 0);
 354         struct mdstat_ent *md;
 355         struct map_ent *map = NULL;
 356         int mdp = get_mdp_major();
 357         int require_homehost;
 358         char sys_hostname[256];
 359         char *homehost = conf_get_homehost(&require_homehost);
 360
 361         if (homehost == NULL || strcmp(homehost, "<system>")==0) {
 362                 if (gethostname(sys_hostname, sizeof(sys_hostname)) == 0) {
 363                         sys_hostname[sizeof(sys_hostname)-1] = 0;
 364                         homehost = sys_hostname;
 365                 }
 366         }
 367
 368         for (md = mdstat ; md ; md = md->next) {
 369                 struct mdinfo *sra = sysfs_read(-1, md->devnum, GET_DEVS);
 370                 struct mdinfo *sd;
 371
 372                 if (!sra)
 373                         continue;
 374
 375                 for (sd = sra->devs ; sd ; sd = sd->next) {
 376                         char namebuf[100];
 377                         char dn[30];
 378                         int dfd;
 379                         int ok;
 380                         struct supertype *st;
 381                         char *path;
 382                         struct mdinfo info;
 383
 384                         sprintf(dn, "%d:%d", sd->disk.major, sd->disk.minor);
 385                         dfd = dev_open(dn, O_RDONLY);
 386                         if (dfd < 0)
 387                                 continue;
 388                         st = guess_super(dfd);
 389                         if ( st == NULL)
 390                                 ok = -1;
 391                         else {
 392                                 set_member_info(st, md);
 393                                 ok = st->ss->load_super(st, dfd, NULL);
 394                         }
 395                         close(dfd);
 396                         if (ok != 0)
 397                                 continue;
 398                         st->ss->getinfo_super(st, &info);
 399                         if (md->devnum >= 0)
 400                                 path = map_dev(MD_MAJOR, md->devnum, 0);
 401                         else
 402                                 path = map_dev(mdp, (-1-md->devnum)<< 6, 0);
 403                         if (path == NULL ||
 404                             strncmp(path, "/dev/md/", 8) != 0) {
 405                                 /* We would really like a name that provides
 406                                  * an MD_DEVNAME for udev.
 407                                  * The name needs to be unique both in /dev/md/
 408                                  * and in this mapfile.
 409                                  * It needs to match watch -I or -As would come
 410                                  * up with.
 411                                  * That means:
 412                                  *   Check if array is in mdadm.conf
 413                                  *        - if so use that.
 414                                  *   determine trustworthy from homehost etc
 415                                  *   find a unique name based on metadata name.
 416                                  *
 417                                  */
 418                                 struct mddev_ident_s *match = conf_match(&info, st);
 419                                 struct stat stb;
 420                                 if (match && match->devname && match->devname[0] == '/') {
 421                                         path = match->devname;
 422                                         if (path[0] != '/') {
 423                                                 strcpy(namebuf, "/dev/md/");
 424                                                 strcat(namebuf, path);
 425                                                 path = namebuf;
 426                                         }
 427                                 } else {
 428                                         int unum = 0;
 429                                         char *sep = "_";
 430                                         const char *name;
 431                                         int conflict = 1;
 432                                         if ((homehost == NULL ||
 433                                              st->ss->match_home(st, homehost) != 1) &&
 434                                             st->ss->match_home(st, "any") != 1 &&
 435                                             (require_homehost
 436                                              || ! conf_name_is_free(info.name)))
 437                                                 /* require a numeric suffix */
 438                                                 unum = 0;
 439                                         else
 440                                                 /* allow name to be used as-is if no conflict */
 441                                                 unum = -1;
 442                                         name = info.name;
 443                                         if (!*name) {
 444                                                 name = st->ss->name;
 445                                                 if (!isdigit(name[strlen(name)-1]) &&
 446                                                     unum == -1) {
 447                                                         unum = 0;
 448                                                         sep = "";
 449                                                 }
 450                                         }
 451                                         if (strchr(name, ':'))
 452                                                 /* probably a uniquifying
 453                                                  * hostname prefix.  Allow
 454                                                  * without a suffix
 455                                                  */
 456                                                 unum = -1;
 457
 458                                         while (conflict) {
 459                                                 if (unum >= 0)
 460                                                         sprintf(namebuf, "/dev/md/%s%s%d",
 461                                                                 name, sep, unum);
 462                                                 else
 463                                                         sprintf(namebuf, "/dev/md/%s",
 464                                                                 name);
 465                                                 unum++;
 466                                                 if (lstat(namebuf, &stb) != 0 &&
 467                                                     (map == NULL ||
 468                                                      !map_by_name(&map, namebuf+8)))
 469                                                         conflict = 0;
 470                                         }
 471                                         path = namebuf;
 472                                 }
 473                         }
 474                         map_add(&map, md->devnum,
 475                                 info.text_version,
 476                                 info.uuid, path);
 477                         st->ss->free_super(st);
 478                         break;
 479                 }
 480                 sysfs_free(sra);
 481         }
 482         /* Only trigger a change if we wrote a new map file */
 483         if (map_write(map))
 484                 for (md = mdstat ; md ; md = md->next) {
 485                         struct mdinfo *sra = sysfs_read(-1, md->devnum,
 486                                                         GET_VERSION);
 487                         if (sra)
 488                                 sysfs_uevent(sra, "change");
 489                         sysfs_free(sra);
 490                 }
 491         map_free(map);
 492         free_mdstat(mdstat);
 493 }