mapfile.c

   1 /*
   2  * mapfile - keep track of uuid <-> array mapping. Part of:
   3  * mdadm - manage Linux "md" devices aka RAID arrays.
   4  *
   5  * Copyright (C) 2006-2010 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 /* The mapfile 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 best place for the mapfile wold be /var/run/mdadm/map.  However
  42  * it is needed during initramfs early-boot, and /var/run doesn't exist there
  43  * and certainly doesn't persist through to normal boot.
  44  * So we store it in /dev/.mdadm/map but allow this to be changed at
  45  * compile time. via MAP_DIR and MAP_FILE
  46  *
  47  */
  48 #include        "mdadm.h"
  49 #include        <sys/file.h>
  50 #include        <ctype.h>
  51
  52 #ifndef MAP_DIR
  53 #define MAP_DIR "/dev/.mdadm"
  54 #define MAP_FILE "map"
  55 #endif
  56
  57 #define MAP_READ 0
  58 #define MAP_NEW 1
  59 #define MAP_LOCK 2
  60 #define MAP_DIRNAME 3
  61 #define mapnames(dir, base) { \
  62
  63 char *mapname[4] = {
  64         MAP_DIR "/" MAP_FILE,
  65         MAP_DIR "/" MAP_FILE ".new",
  66         MAP_DIR "/" MAP_FILE ".lock",
  67         MAP_DIR
  68 };
  69
  70 int mapmode[3] = { O_RDONLY, O_RDWR|O_CREAT, O_RDWR|O_CREAT|O_TRUNC };
  71 char *mapsmode[3] = { "r", "w", "w"};
  72
  73 FILE *open_map(int modenum)
  74 {
  75         int fd;
  76         if ((mapmode[modenum] & O_CREAT))
  77                 /* Attempt to create directory, don't worry about
  78                  * failure.
  79                  */
  80                 (void)mkdir(mapname[MAP_DIRNAME], 0755);
  81         fd = open(mapname[modenum], mapmode[modenum], 0600);
  82         if (fd >= 0)
  83                 return fdopen(fd, mapsmode[modenum]);
  84         return NULL;
  85 }
  86
  87 int map_write(struct map_ent *mel)
  88 {
  89         FILE *f;
  90         int err;
  91
  92         f = open_map(MAP_NEW);
  93
  94         if (!f)
  95                 return 0;
  96         for (; mel; mel = mel->next) {
  97                 if (mel->bad)
  98                         continue;
  99                 if (mel->devnum < 0)
 100                         fprintf(f, "mdp%d ", -1-mel->devnum);
 101                 else
 102                         fprintf(f, "md%d ", mel->devnum);
 103                 fprintf(f, "%s ", mel->metadata);
 104                 fprintf(f, "%08x:%08x:%08x:%08x ", mel->uuid[0],
 105                         mel->uuid[1], mel->uuid[2], mel->uuid[3]);
 106                 fprintf(f, "%s\n", mel->path?:"");
 107         }
 108         fflush(f);
 109         err = ferror(f);
 110         fclose(f);
 111         if (err) {
 112                 unlink(mapname[1]);
 113                 return 0;
 114         }
 115         return rename(mapname[1],
 116                       mapname[0]) == 0;
 117 }
 118
 119
 120 static FILE *lf = NULL;
 121 int map_lock(struct map_ent **melp)
 122 {
 123         while (lf == NULL) {
 124                 struct stat buf;
 125                 lf = open_map(MAP_LOCK);
 126                 if (lf == NULL)
 127                         return -1;
 128                 if (flock(fileno(lf), LOCK_EX) != 0) {
 129                         fclose(lf);
 130                         lf = NULL;
 131                         return -1;
 132                 }
 133                 if (fstat(fileno(lf), &buf) != 0 ||
 134                     buf.st_nlink == 0) {
 135                         /* The owner of the lock unlinked it,
 136                          * so we have a lock on a stale file,
 137                          * try again
 138                          */
 139                         fclose(lf);
 140                         lf = NULL;
 141                 }
 142         }
 143         if (*melp)
 144                 map_free(*melp);
 145         map_read(melp);
 146         return 0;
 147 }
 148
 149 void map_unlock(struct map_ent **melp)
 150 {
 151         if (lf) {
 152                 /* must unlink before closing the file,
 153                  * as only the owner of the lock may
 154                  * unlink the file
 155                  */
 156                 unlink(mapname[2]);
 157                 fclose(lf);
 158         }
 159         lf = NULL;
 160 }
 161
 162 void map_fork(void)
 163 {
 164         /* We are forking, so must close the lock file.
 165          * Don't risk flushing anything though.
 166          */
 167         if (lf) {
 168                 close(fileno(lf));
 169                 fclose(lf);
 170                 lf = NULL;
 171         }
 172 }
 173
 174 void map_add(struct map_ent **melp,
 175             int devnum, char *metadata, int uuid[4], char *path)
 176 {
 177         struct map_ent *me = malloc(sizeof(*me));
 178
 179         me->devnum = devnum;
 180         strcpy(me->metadata, metadata);
 181         memcpy(me->uuid, uuid, 16);
 182         me->path = path ? strdup(path) : NULL;
 183         me->next = *melp;
 184         me->bad = 0;
 185         *melp = me;
 186 }
 187
 188 void map_read(struct map_ent **melp)
 189 {
 190         FILE *f;
 191         char buf[8192];
 192         char path[200];
 193         int devnum, uuid[4];
 194         char metadata[30];
 195         char nam[4];
 196
 197         *melp = NULL;
 198
 199         f = open_map(MAP_READ);
 200         if (!f) {
 201                 RebuildMap();
 202                 f = open_map(MAP_READ);
 203         }
 204         if (!f)
 205                 return;
 206
 207         while (fgets(buf, sizeof(buf), f)) {
 208                 path[0] = 0;
 209                 if (sscanf(buf, " %3[mdp]%d %s %x:%x:%x:%x %200s",
 210                            nam, &devnum, metadata, uuid, uuid+1,
 211                            uuid+2, uuid+3, path) >= 7) {
 212                         if (strncmp(nam, "md", 2) != 0)
 213                                 continue;
 214                         if (nam[2] == 'p')
 215                                 devnum = -1 - devnum;
 216                         map_add(melp, devnum, metadata, uuid, path);
 217                 }
 218         }
 219         fclose(f);
 220 }
 221
 222 void map_free(struct map_ent *map)
 223 {
 224         while (map) {
 225                 struct map_ent *mp = map;
 226                 map = mp->next;
 227                 free(mp->path);
 228                 free(mp);
 229         }
 230 }
 231
 232 int map_update(struct map_ent **mpp, int devnum, char *metadata,
 233                int *uuid, char *path)
 234 {
 235         struct map_ent *map, *mp;
 236         int rv;
 237
 238         if (mpp && *mpp)
 239                 map = *mpp;
 240         else
 241                 map_read(&map);
 242
 243         for (mp = map ; mp ; mp=mp->next)
 244                 if (mp->devnum == devnum) {
 245                         strcpy(mp->metadata, metadata);
 246                         memcpy(mp->uuid, uuid, 16);
 247                         free(mp->path);
 248                         mp->path = path ? strdup(path) : NULL;
 249                         break;
 250                 }
 251         if (!mp)
 252                 map_add(&map, devnum, metadata, uuid, path);
 253         if (mpp)
 254                 *mpp = NULL;
 255         rv = map_write(map);
 256         map_free(map);
 257         return rv;
 258 }
 259
 260 void map_delete(struct map_ent **mapp, int devnum)
 261 {
 262         struct map_ent *mp;
 263
 264         if (*mapp == NULL)
 265                 map_read(mapp);
 266
 267         for (mp = *mapp; mp; mp = *mapp) {
 268                 if (mp->devnum == devnum) {
 269                         *mapp = mp->next;
 270                         free(mp->path);
 271                         free(mp);
 272                 } else
 273                         mapp = & mp->next;
 274         }
 275 }
 276
 277 void map_remove(struct map_ent **mapp, int devnum)
 278 {
 279         if (devnum == NoMdDev)
 280                 return;
 281
 282         map_delete(mapp, devnum);
 283         map_write(*mapp);
 284         map_free(*mapp);
 285 }
 286
 287 struct map_ent *map_by_uuid(struct map_ent **map, int uuid[4])
 288 {
 289         struct map_ent *mp;
 290         if (!*map)
 291                 map_read(map);
 292
 293         for (mp = *map ; mp ; mp = mp->next) {
 294                 if (memcmp(uuid, mp->uuid, 16) != 0)
 295                         continue;
 296                 if (!mddev_busy(mp->devnum)) {
 297                         mp->bad = 1;
 298                         continue;
 299                 }
 300                 return mp;
 301         }
 302         return NULL;
 303 }
 304
 305 struct map_ent *map_by_devnum(struct map_ent **map, int devnum)
 306 {
 307         struct map_ent *mp;
 308         if (!*map)
 309                 map_read(map);
 310
 311         for (mp = *map ; mp ; mp = mp->next) {
 312                 if (mp->devnum != devnum)
 313                         continue;
 314                 if (!mddev_busy(mp->devnum)) {
 315                         mp->bad = 1;
 316                         continue;
 317                 }
 318                 return mp;
 319         }
 320         return NULL;
 321 }
 322
 323 struct map_ent *map_by_name(struct map_ent **map, char *name)
 324 {
 325         struct map_ent *mp;
 326         if (!*map)
 327                 map_read(map);
 328
 329         for (mp = *map ; mp ; mp = mp->next) {
 330                 if (!mp->path)
 331                         continue;
 332                 if (strncmp(mp->path, "/dev/md/", 8) != 0)
 333                         continue;
 334                 if (strcmp(mp->path+8, name) != 0)
 335                         continue;
 336                 if (!mddev_busy(mp->devnum)) {
 337                         mp->bad = 1;
 338                         continue;
 339                 }
 340                 return mp;
 341         }
 342         return NULL;
 343 }
 344
 345 /* sets the proper subarray and container_dev according to the metadata
 346  * version super_by_fd does this automatically, this routine is meant as
 347  * a supplement for guess_super()
 348  */
 349 static char *get_member_info(struct mdstat_ent *ent)
 350 {
 351
 352         if (ent->metadata_version == NULL ||
 353             strncmp(ent->metadata_version, "external:", 9) != 0)
 354                 return NULL;
 355
 356         if (is_subarray(&ent->metadata_version[9])) {
 357                 char *subarray;
 358
 359                 subarray = strrchr(ent->metadata_version, '/');
 360                 return subarray + 1;
 361         }
 362         return NULL;
 363 }
 364
 365 void RebuildMap(void)
 366 {
 367         struct mdstat_ent *mdstat = mdstat_read(0, 0);
 368         struct mdstat_ent *md;
 369         struct map_ent *map = NULL;
 370         int mdp = get_mdp_major();
 371         int require_homehost;
 372         char sys_hostname[256];
 373         char *homehost = conf_get_homehost(&require_homehost);
 374
 375         if (homehost == NULL || strcmp(homehost, "<system>")==0) {
 376                 if (gethostname(sys_hostname, sizeof(sys_hostname)) == 0) {
 377                         sys_hostname[sizeof(sys_hostname)-1] = 0;
 378                         homehost = sys_hostname;
 379                 }
 380         }
 381
 382         for (md = mdstat ; md ; md = md->next) {
 383                 struct mdinfo *sra = sysfs_read(-1, md->devnum, GET_DEVS);
 384                 struct mdinfo *sd;
 385
 386                 if (!sra)
 387                         continue;
 388
 389                 for (sd = sra->devs ; sd ; sd = sd->next) {
 390                         char namebuf[100];
 391                         char dn[30];
 392                         int dfd;
 393                         int ok;
 394                         struct supertype *st;
 395                         char *subarray = NULL;
 396                         char *path;
 397                         struct mdinfo *info;
 398
 399                         sprintf(dn, "%d:%d", sd->disk.major, sd->disk.minor);
 400                         dfd = dev_open(dn, O_RDONLY);
 401                         if (dfd < 0)
 402                                 continue;
 403                         st = guess_super(dfd);
 404                         if ( st == NULL)
 405                                 ok = -1;
 406                         else {
 407                                 subarray = get_member_info(md);
 408                                 ok = st->ss->load_super(st, dfd, NULL);
 409                         }
 410                         close(dfd);
 411                         if (ok != 0)
 412                                 continue;
 413                         info = st->ss->container_content(st, subarray);
 414
 415                         if (md->devnum >= 0)
 416                                 path = map_dev(MD_MAJOR, md->devnum, 0);
 417                         else
 418                                 path = map_dev(mdp, (-1-md->devnum)<< 6, 0);
 419                         if (path == NULL ||
 420                             strncmp(path, "/dev/md/", 8) != 0) {
 421                                 /* We would really like a name that provides
 422                                  * an MD_DEVNAME for udev.
 423                                  * The name needs to be unique both in /dev/md/
 424                                  * and in this mapfile.
 425                                  * It needs to match watch -I or -As would come
 426                                  * up with.
 427                                  * That means:
 428                                  *   Check if array is in mdadm.conf
 429                                  *        - if so use that.
 430                                  *   determine trustworthy from homehost etc
 431                                  *   find a unique name based on metadata name.
 432                                  *
 433                                  */
 434                                 struct mddev_ident *match = conf_match(st, info,
 435                                                                        NULL, 0,
 436                                                                        NULL);
 437                                 struct stat stb;
 438                                 if (match && match->devname && match->devname[0] == '/') {
 439                                         path = match->devname;
 440                                         if (path[0] != '/') {
 441                                                 strcpy(namebuf, "/dev/md/");
 442                                                 strcat(namebuf, path);
 443                                                 path = namebuf;
 444                                         }
 445                                 } else {
 446                                         int unum = 0;
 447                                         char *sep = "_";
 448                                         const char *name;
 449                                         int conflict = 1;
 450                                         if ((homehost == NULL ||
 451                                              st->ss->match_home(st, homehost) != 1) &&
 452                                             st->ss->match_home(st, "any") != 1 &&
 453                                             (require_homehost
 454                                              || ! conf_name_is_free(info->name)))
 455                                                 /* require a numeric suffix */
 456                                                 unum = 0;
 457                                         else
 458                                                 /* allow name to be used as-is if no conflict */
 459                                                 unum = -1;
 460                                         name = info->name;
 461                                         if (!*name) {
 462                                                 name = st->ss->name;
 463                                                 if (!isdigit(name[strlen(name)-1]) &&
 464                                                     unum == -1) {
 465                                                         unum = 0;
 466                                                         sep = "";
 467                                                 }
 468                                         }
 469                                         if (strchr(name, ':'))
 470                                                 /* probably a uniquifying
 471                                                  * hostname prefix.  Allow
 472                                                  * without a suffix
 473                                                  */
 474                                                 unum = -1;
 475
 476                                         while (conflict) {
 477                                                 if (unum >= 0)
 478                                                         sprintf(namebuf, "/dev/md/%s%s%d",
 479                                                                 name, sep, unum);
 480                                                 else
 481                                                         sprintf(namebuf, "/dev/md/%s",
 482                                                                 name);
 483                                                 unum++;
 484                                                 if (lstat(namebuf, &stb) != 0 &&
 485                                                     (map == NULL ||
 486                                                      !map_by_name(&map, namebuf+8)))
 487                                                         conflict = 0;
 488                                         }
 489                                         path = namebuf;
 490                                 }
 491                         }
 492                         map_add(&map, md->devnum,
 493                                 info->text_version,
 494                                 info->uuid, path);
 495                         st->ss->free_super(st);
 496                         free(info);
 497                         break;
 498                 }
 499                 sysfs_free(sra);
 500         }
 501         /* Only trigger a change if we wrote a new map file */
 502         if (map_write(map))
 503                 for (md = mdstat ; md ; md = md->next) {
 504                         struct mdinfo *sra = sysfs_read(-1, md->devnum,
 505                                                         GET_VERSION);
 506                         if (sra)
 507                                 sysfs_uevent(sra, "change");
 508                         sysfs_free(sra);
 509                 }
 510         map_free(map);
 511         free_mdstat(mdstat);
 512 }