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  /dev/.mdadm/map(changable at compile time).
  46  * We read from the first one that exists and write to the first
  47  * one that we can.
  48  */
  49 #include        "mdadm.h"
  50 #include        <sys/file.h>
  51 #include        <ctype.h>
  52
  53 #define MAP_READ 0
  54 #define MAP_NEW 1
  55 #define MAP_LOCK 2
  56 #define MAP_DIRNAME 3
  57 #define mapnames(dir, base) { \
  58                         dir "/" base,                           \
  59                         dir "/" base ".new",                    \
  60                         dir "/" base ".lock",                   \
  61                         dir }
  62
  63 #define MAP_DIRS 2
  64 char *mapname[MAP_DIRS][4] = {
  65         mapnames("/var/run/mdadm", "map"),
  66         mapnames(MAP_DIR, MAP_FILE),
  67 };
  68
  69 int mapmode[3] = { O_RDONLY, O_RDWR|O_CREAT, O_RDWR|O_CREAT|O_TRUNC };
  70 char *mapsmode[3] = { "r", "w", "w"};
  71
  72 FILE *open_map(int modenum, int *choice)
  73 {
  74         int i;
  75
  76         for (i = 0 ; i <= MAP_DIRS ; i++) {
  77                 int fd;
  78                 if ((mapmode[modenum] & O_CREAT))
  79                         /* Attempt to create directory, don't worry about
  80                          * failure.
  81                          */
  82                         (void)mkdir(mapname[i][MAP_DIRNAME], 0755);
  83                 fd = open(mapname[i][modenum], mapmode[modenum], 0600);
  84                 if (fd >= 0) {
  85                         *choice = i;
  86                         return fdopen(fd, mapsmode[modenum]);
  87                 }
  88         }
  89         return NULL;
  90 }
  91
  92 int map_write(struct map_ent *mel)
  93 {
  94         FILE *f;
  95         int err;
  96         int which;
  97
  98         f = open_map(MAP_NEW, &which);
  99
 100         if (!f)
 101                 return 0;
 102         for (; mel; mel = mel->next) {
 103                 if (mel->bad)
 104                         continue;
 105                 if (mel->devnum < 0)
 106                         fprintf(f, "mdp%d ", -1-mel->devnum);
 107                 else
 108                         fprintf(f, "md%d ", mel->devnum);
 109                 fprintf(f, "%s ", mel->metadata);
 110                 fprintf(f, "%08x:%08x:%08x:%08x ", mel->uuid[0],
 111                         mel->uuid[1], mel->uuid[2], mel->uuid[3]);
 112                 fprintf(f, "%s\n", mel->path?:"");
 113         }
 114         fflush(f);
 115         err = ferror(f);
 116         fclose(f);
 117         if (err) {
 118                 unlink(mapname[which][1]);
 119                 return 0;
 120         }
 121         return rename(mapname[which][1],
 122                       mapname[which][0]) == 0;
 123 }
 124
 125
 126 static FILE *lf = NULL;
 127 static int lwhich = 0;
 128 int map_lock(struct map_ent **melp)
 129 {
 130         while (lf == NULL) {
 131                 struct stat buf;
 132                 lf = open_map(MAP_LOCK, &lwhich);
 133                 if (lf == NULL)
 134                         return -1;
 135                 if (flock(fileno(lf), LOCK_EX) != 0) {
 136                         fclose(lf);
 137                         lf = NULL;
 138                         return -1;
 139                 }
 140                 if (fstat(fileno(lf), &buf) != 0 ||
 141                     buf.st_nlink == 0) {
 142                         /* The owner of the lock unlinked it,
 143                          * so we have a lock on a stale file,
 144                          * try again
 145                          */
 146                         fclose(lf);
 147                         lf = NULL;
 148                 }
 149         }
 150         if (*melp)
 151                 map_free(*melp);
 152         map_read(melp);
 153         return 0;
 154 }
 155
 156 void map_unlock(struct map_ent **melp)
 157 {
 158         if (lf) {
 159                 /* must unlink before closing the file,
 160                  * as only the owner of the lock may
 161                  * unlink the file
 162                  */
 163                 unlink(mapname[lwhich][2]);
 164                 fclose(lf);
 165         }
 166         lf = NULL;
 167 }
 168
 169 void map_add(struct map_ent **melp,
 170             int devnum, char *metadata, int uuid[4], char *path)
 171 {
 172         struct map_ent *me = malloc(sizeof(*me));
 173
 174         me->devnum = devnum;
 175         strcpy(me->metadata, metadata);
 176         memcpy(me->uuid, uuid, 16);
 177         me->path = path ? strdup(path) : NULL;
 178         me->next = *melp;
 179         me->bad = 0;
 180         *melp = me;
 181 }
 182
 183 void map_read(struct map_ent **melp)
 184 {
 185         FILE *f;
 186         char buf[8192];
 187         char path[200];
 188         int devnum, uuid[4];
 189         char metadata[30];
 190         char nam[4];
 191         int which;
 192
 193         *melp = NULL;
 194
 195         f = open_map(MAP_READ, &which);
 196         if (!f) {
 197                 RebuildMap();
 198                 f = open_map(MAP_READ, &which);
 199         }
 200         if (!f)
 201                 return;
 202
 203         while (fgets(buf, sizeof(buf), f)) {
 204                 path[0] = 0;
 205                 if (sscanf(buf, " %3[mdp]%d %s %x:%x:%x:%x %200s",
 206                            nam, &devnum, metadata, uuid, uuid+1,
 207                            uuid+2, uuid+3, path) >= 7) {
 208                         if (strncmp(nam, "md", 2) != 0)
 209                                 continue;
 210                         if (nam[2] == 'p')
 211                                 devnum = -1 - devnum;
 212                         map_add(melp, devnum, metadata, uuid, path);
 213                 }
 214         }
 215         fclose(f);
 216 }
 217
 218 void map_free(struct map_ent *map)
 219 {
 220         while (map) {
 221                 struct map_ent *mp = map;
 222                 map = mp->next;
 223                 free(mp->path);
 224                 free(mp);
 225         }
 226 }
 227
 228 int map_update(struct map_ent **mpp, int devnum, char *metadata,
 229                int *uuid, char *path)
 230 {
 231         struct map_ent *map, *mp;
 232         int rv;
 233
 234         if (mpp && *mpp)
 235                 map = *mpp;
 236         else
 237                 map_read(&map);
 238
 239         for (mp = map ; mp ; mp=mp->next)
 240                 if (mp->devnum == devnum) {
 241                         strcpy(mp->metadata, metadata);
 242                         memcpy(mp->uuid, uuid, 16);
 243                         free(mp->path);
 244                         mp->path = path ? strdup(path) : NULL;
 245                         break;
 246                 }
 247         if (!mp)
 248                 map_add(&map, devnum, metadata, uuid, path);
 249         if (mpp)
 250                 *mpp = NULL;
 251         rv = map_write(map);
 252         map_free(map);
 253         return rv;
 254 }
 255
 256 void map_delete(struct map_ent **mapp, int devnum)
 257 {
 258         struct map_ent *mp;
 259
 260         if (*mapp == NULL)
 261                 map_read(mapp);
 262
 263         for (mp = *mapp; mp; mp = *mapp) {
 264                 if (mp->devnum == devnum) {
 265                         *mapp = mp->next;
 266                         free(mp->path);
 267                         free(mp);
 268                 } else
 269                         mapp = & mp->next;
 270         }
 271 }
 272
 273 void map_remove(struct map_ent **mapp, int devnum)
 274 {
 275         if (devnum == NoMdDev)
 276                 return;
 277
 278         map_delete(mapp, devnum);
 279         map_write(*mapp);
 280         map_free(*mapp);
 281 }
 282
 283 struct map_ent *map_by_uuid(struct map_ent **map, int uuid[4])
 284 {
 285         struct map_ent *mp;
 286         if (!*map)
 287                 map_read(map);
 288
 289         for (mp = *map ; mp ; mp = mp->next) {
 290                 if (memcmp(uuid, mp->uuid, 16) != 0)
 291                         continue;
 292                 if (!mddev_busy(mp->devnum)) {
 293                         mp->bad = 1;
 294                         continue;
 295                 }
 296                 return mp;
 297         }
 298         return NULL;
 299 }
 300
 301 struct map_ent *map_by_devnum(struct map_ent **map, int devnum)
 302 {
 303         struct map_ent *mp;
 304         if (!*map)
 305                 map_read(map);
 306
 307         for (mp = *map ; mp ; mp = mp->next) {
 308                 if (mp->devnum != devnum)
 309                         continue;
 310                 if (!mddev_busy(mp->devnum)) {
 311                         mp->bad = 1;
 312                         continue;
 313                 }
 314                 return mp;
 315         }
 316         return NULL;
 317 }
 318
 319 struct map_ent *map_by_name(struct map_ent **map, char *name)
 320 {
 321         struct map_ent *mp;
 322         if (!*map)
 323                 map_read(map);
 324
 325         for (mp = *map ; mp ; mp = mp->next) {
 326                 if (!mp->path)
 327                         continue;
 328                 if (strncmp(mp->path, "/dev/md/", 8) != 0)
 329                         continue;
 330                 if (strcmp(mp->path+8, name) != 0)
 331                         continue;
 332                 if (!mddev_busy(mp->devnum)) {
 333                         mp->bad = 1;
 334                         continue;
 335                 }
 336                 return mp;
 337         }
 338         return NULL;
 339 }
 340
 341 /* sets the proper subarray and container_dev according to the metadata
 342  * version super_by_fd does this automatically, this routine is meant as
 343  * a supplement for guess_super()
 344  */
 345 static void set_member_info(struct supertype *st, struct mdstat_ent *ent)
 346 {
 347
 348         st->subarray[0] = '\0';
 349
 350         if (ent->metadata_version == NULL ||
 351             strncmp(ent->metadata_version, "external:", 9) != 0)
 352                 return;
 353
 354         if (is_subarray(&ent->metadata_version[9])) {
 355                 char version[strlen(ent->metadata_version)+1];
 356                 char *subarray;
 357                 char *name = &version[10];
 358
 359                 strcpy(version, ent->metadata_version);
 360                 subarray = strrchr(version, '/');
 361                 name = &version[10];
 362
 363                 if (!subarray)
 364                         return;
 365                 *subarray++ = '\0';
 366
 367                 st->container_dev = devname2devnum(name);
 368                 strncpy(st->subarray, subarray, sizeof(st->subarray));
 369         }
 370 }
 371
 372 void RebuildMap(void)
 373 {
 374         struct mdstat_ent *mdstat = mdstat_read(0, 0);
 375         struct mdstat_ent *md;
 376         struct map_ent *map = NULL;
 377         int mdp = get_mdp_major();
 378         int require_homehost;
 379         char sys_hostname[256];
 380         char *homehost = conf_get_homehost(&require_homehost);
 381
 382         if (homehost == NULL || strcmp(homehost, "<system>")==0) {
 383                 if (gethostname(sys_hostname, sizeof(sys_hostname)) == 0) {
 384                         sys_hostname[sizeof(sys_hostname)-1] = 0;
 385                         homehost = sys_hostname;
 386                 }
 387         }
 388
 389         for (md = mdstat ; md ; md = md->next) {
 390                 struct mdinfo *sra = sysfs_read(-1, md->devnum, GET_DEVS);
 391                 struct mdinfo *sd;
 392
 393                 if (!sra)
 394                         continue;
 395
 396                 for (sd = sra->devs ; sd ; sd = sd->next) {
 397                         char namebuf[100];
 398                         char dn[30];
 399                         int dfd;
 400                         int ok;
 401                         struct supertype *st;
 402                         char *path;
 403                         struct mdinfo info;
 404
 405                         sprintf(dn, "%d:%d", sd->disk.major, sd->disk.minor);
 406                         dfd = dev_open(dn, O_RDONLY);
 407                         if (dfd < 0)
 408                                 continue;
 409                         st = guess_super(dfd);
 410                         if ( st == NULL)
 411                                 ok = -1;
 412                         else {
 413                                 set_member_info(st, md);
 414                                 ok = st->ss->load_super(st, dfd, NULL);
 415                         }
 416                         close(dfd);
 417                         if (ok != 0)
 418                                 continue;
 419                         st->ss->getinfo_super(st, &info);
 420                         if (md->devnum >= 0)
 421                                 path = map_dev(MD_MAJOR, md->devnum, 0);
 422                         else
 423                                 path = map_dev(mdp, (-1-md->devnum)<< 6, 0);
 424                         if (path == NULL ||
 425                             strncmp(path, "/dev/md/", 8) != 0) {
 426                                 /* We would really like a name that provides
 427                                  * an MD_DEVNAME for udev.
 428                                  * The name needs to be unique both in /dev/md/
 429                                  * and in this mapfile.
 430                                  * It needs to match watch -I or -As would come
 431                                  * up with.
 432                                  * That means:
 433                                  *   Check if array is in mdadm.conf
 434                                  *        - if so use that.
 435                                  *   determine trustworthy from homehost etc
 436                                  *   find a unique name based on metadata name.
 437                                  *
 438                                  */
 439                                 struct mddev_ident_s *match = conf_match(&info, st);
 440                                 struct stat stb;
 441                                 if (match && match->devname && match->devname[0] == '/') {
 442                                         path = match->devname;
 443                                         if (path[0] != '/') {
 444                                                 strcpy(namebuf, "/dev/md/");
 445                                                 strcat(namebuf, path);
 446                                                 path = namebuf;
 447                                         }
 448                                 } else {
 449                                         int unum = 0;
 450                                         char *sep = "_";
 451                                         const char *name;
 452                                         int conflict = 1;
 453                                         if ((homehost == NULL ||
 454                                              st->ss->match_home(st, homehost) != 1) &&
 455                                             st->ss->match_home(st, "any") != 1 &&
 456                                             (require_homehost
 457                                              || ! conf_name_is_free(info.name)))
 458                                                 /* require a numeric suffix */
 459                                                 unum = 0;
 460                                         else
 461                                                 /* allow name to be used as-is if no conflict */
 462                                                 unum = -1;
 463                                         name = info.name;
 464                                         if (!*name) {
 465                                                 name = st->ss->name;
 466                                                 if (!isdigit(name[strlen(name)-1]) &&
 467                                                     unum == -1) {
 468                                                         unum = 0;
 469                                                         sep = "";
 470                                                 }
 471                                         }
 472                                         if (strchr(name, ':'))
 473                                                 /* probably a uniquifying
 474                                                  * hostname prefix.  Allow
 475                                                  * without a suffix
 476                                                  */
 477                                                 unum = -1;
 478
 479                                         while (conflict) {
 480                                                 if (unum >= 0)
 481                                                         sprintf(namebuf, "/dev/md/%s%s%d",
 482                                                                 name, sep, unum);
 483                                                 else
 484                                                         sprintf(namebuf, "/dev/md/%s",
 485                                                                 name);
 486                                                 unum++;
 487                                                 if (lstat(namebuf, &stb) != 0 &&
 488                                                     (map == NULL ||
 489                                                      !map_by_name(&map, namebuf+8)))
 490                                                         conflict = 0;
 491                                         }
 492                                         path = namebuf;
 493                                 }
 494                         }
 495                         map_add(&map, md->devnum,
 496                                 info.text_version,
 497                                 info.uuid, path);
 498                         st->ss->free_super(st);
 499                         break;
 500                 }
 501                 sysfs_free(sra);
 502         }
 503         /* Only trigger a change if we wrote a new map file */
 504         if (map_write(map))
 505                 for (md = mdstat ; md ; md = md->next) {
 506                         struct mdinfo *sra = sysfs_read(-1, md->devnum,
 507                                                         GET_VERSION);
 508                         if (sra)
 509                                 sysfs_uevent(sra, "change");
 510                         sysfs_free(sra);
 511                 }
 512         map_free(map);
 513         free_mdstat(mdstat);
 514 }