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 is /run/mdadm/map.  Distros and users
  42  * which have not switched to /run yet can choose a different location
  43  * at compile time via MAP_DIR and MAP_FILE.
  44  */
  45 #include        "mdadm.h"
  46 #include        "xmalloc.h"
  47
  48 #include        <sys/file.h>
  49 #include        <ctype.h>
  50
  51 #define MAP_READ 0
  52 #define MAP_NEW 1
  53 #define MAP_LOCK 2
  54 #define MAP_DIRNAME 3
  55
  56 char *mapname[4] = {
  57         MAP_DIR "/" MAP_FILE,
  58         MAP_DIR "/" MAP_FILE ".new",
  59         MAP_DIR "/" MAP_FILE ".lock",
  60         MAP_DIR
  61 };
  62
  63 int mapmode[3] = { O_RDONLY, O_RDWR|O_CREAT, O_RDWR|O_CREAT|O_TRUNC };
  64 char *mapsmode[3] = { "r", "w", "w"};
  65
  66 FILE *open_map(int modenum)
  67 {
  68         int fd;
  69         if ((mapmode[modenum] & O_CREAT))
  70                 /* Attempt to create directory, don't worry about
  71                  * failure.
  72                  */
  73                 (void)mkdir(mapname[MAP_DIRNAME], 0755);
  74         fd = open(mapname[modenum], mapmode[modenum], 0600);
  75         if (fd >= 0)
  76                 return fdopen(fd, mapsmode[modenum]);
  77         return NULL;
  78 }
  79
  80 int map_write(struct map_ent *mel)
  81 {
  82         FILE *f;
  83         int err;
  84
  85         f = open_map(MAP_NEW);
  86
  87         if (!f)
  88                 return 0;
  89         for (; mel; mel = mel->next) {
  90                 if (mel->bad)
  91                         continue;
  92                 fprintf(f, "%s ", mel->devnm);
  93                 fprintf(f, "%s ", mel->metadata);
  94                 fprintf(f, "%08x:%08x:%08x:%08x ", mel->uuid[0],
  95                         mel->uuid[1], mel->uuid[2], mel->uuid[3]);
  96                 fprintf(f, "%s\n", mel->path?:"");
  97         }
  98         fflush(f);
  99         err = ferror(f);
 100         fclose(f);
 101         if (err) {
 102                 unlink(mapname[1]);
 103                 return 0;
 104         }
 105         return rename(mapname[1],
 106                       mapname[0]) == 0;
 107 }
 108
 109 static FILE *lf = NULL;
 110 int map_lock(struct map_ent **melp)
 111 {
 112         while (lf == NULL) {
 113                 struct stat buf;
 114                 lf = open_map(MAP_LOCK);
 115                 if (lf == NULL)
 116                         return -1;
 117                 if (flock(fileno(lf), LOCK_EX) != 0) {
 118                         fclose(lf);
 119                         lf = NULL;
 120                         return -1;
 121                 }
 122                 if (fstat(fileno(lf), &buf) != 0 ||
 123                     buf.st_nlink == 0) {
 124                         /* The owner of the lock unlinked it,
 125                          * so we have a lock on a stale file,
 126                          * try again
 127                          */
 128                         fclose(lf);
 129                         lf = NULL;
 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                 /* must unlink before closing the file,
 142                  * as only the owner of the lock may
 143                  * unlink the file
 144                  */
 145                 unlink(mapname[2]);
 146                 fclose(lf);
 147         }
 148         if (*melp)
 149                 map_free(*melp);
 150         lf = NULL;
 151 }
 152
 153 void map_fork(void)
 154 {
 155         /* We are forking, so must close the lock file.
 156          * Don't risk flushing anything though.
 157          */
 158         if (lf) {
 159                 close(fileno(lf));
 160                 fclose(lf);
 161                 lf = NULL;
 162         }
 163 }
 164
 165 void map_add(struct map_ent **melp,
 166              char * devnm, char *metadata, int uuid[4], char *path)
 167 {
 168         struct map_ent *me = xmalloc(sizeof(*me));
 169
 170         snprintf(me->devnm, sizeof(me->devnm), "%s", devnm);
 171         snprintf(me->metadata, sizeof(me->metadata), "%s", metadata);
 172         memcpy(me->uuid, uuid, 16);
 173         me->path = path ? xstrdup(path) : NULL;
 174         me->next = *melp;
 175         me->bad = 0;
 176         *melp = me;
 177 }
 178
 179 void map_read(struct map_ent **melp)
 180 {
 181         FILE *f;
 182         char buf[8192];
 183         char path[201];
 184         int uuid[4];
 185         char devnm[32];
 186         char metadata[30];
 187
 188         *melp = NULL;
 189
 190         f = open_map(MAP_READ);
 191         if (!f) {
 192                 RebuildMap();
 193                 f = open_map(MAP_READ);
 194         }
 195         if (!f)
 196                 return;
 197
 198         while (fgets(buf, sizeof(buf), f)) {
 199                 path[0] = 0;
 200                 if (sscanf(buf, " %s %s %x:%x:%x:%x %200s",
 201                            devnm, metadata, uuid, uuid+1,
 202                            uuid+2, uuid+3, path) >= 7) {
 203                         map_add(melp, devnm, metadata, uuid, path);
 204                 }
 205         }
 206         fclose(f);
 207 }
 208
 209 void map_free(struct map_ent *map)
 210 {
 211         while (map) {
 212                 struct map_ent *mp = map;
 213                 map = mp->next;
 214                 free(mp->path);
 215                 free(mp);
 216         }
 217 }
 218
 219 int map_update(struct map_ent **mpp, char *devnm, char *metadata,
 220                int uuid[4], char *path)
 221 {
 222         struct map_ent *map, *mp;
 223         int rv;
 224
 225         if (mpp && *mpp)
 226                 map = *mpp;
 227         else
 228                 map_read(&map);
 229
 230         for (mp = map ; mp ; mp=mp->next)
 231                 if (strcmp(mp->devnm, devnm) == 0) {
 232                         snprintf(mp->metadata, sizeof(mp->metadata), "%s", metadata);
 233                         memcpy(mp->uuid, uuid, 16);
 234                         free(mp->path);
 235                         mp->path = path ? xstrdup(path) : NULL;
 236                         mp->bad = 0;
 237                         break;
 238                 }
 239         if (!mp)
 240                 map_add(&map, devnm, metadata, uuid, path);
 241         if (mpp)
 242                 *mpp = NULL;
 243         rv = map_write(map);
 244         map_free(map);
 245         return rv;
 246 }
 247
 248 void map_delete(struct map_ent **mapp, char *devnm)
 249 {
 250         struct map_ent *mp;
 251
 252         if (*mapp == NULL)
 253                 map_read(mapp);
 254
 255         for (mp = *mapp; mp; mp = *mapp) {
 256                 if (strcmp(mp->devnm, devnm) == 0) {
 257                         *mapp = mp->next;
 258                         free(mp->path);
 259                         free(mp);
 260                 } else
 261                         mapp = & mp->next;
 262         }
 263 }
 264
 265 void map_remove(struct map_ent **mapp, char *devnm)
 266 {
 267         if (devnm[0] == 0)
 268                 return;
 269
 270         map_delete(mapp, devnm);
 271         map_write(*mapp);
 272         map_free(*mapp);
 273         *mapp = NULL;
 274 }
 275
 276 struct map_ent *map_by_uuid(struct map_ent **map, int uuid[4])
 277 {
 278         struct map_ent *mp;
 279         if (!*map)
 280                 map_read(map);
 281
 282         for (mp = *map ; mp ; mp = mp->next) {
 283                 if (memcmp(uuid, mp->uuid, 16) != 0)
 284                         continue;
 285                 if (!mddev_busy(mp->devnm)) {
 286                         mp->bad = 1;
 287                         continue;
 288                 }
 289                 return mp;
 290         }
 291         return NULL;
 292 }
 293
 294 struct map_ent *map_by_devnm(struct map_ent **map, char *devnm)
 295 {
 296         struct map_ent *mp;
 297
 298         if (!devnm)
 299                 return NULL;
 300
 301         if (!*map)
 302                 map_read(map);
 303
 304         for (mp = *map ; mp ; mp = mp->next) {
 305                 if (strcmp(mp->devnm, devnm) != 0)
 306                         continue;
 307                 if (!mddev_busy(mp->devnm)) {
 308                         mp->bad = 1;
 309                         continue;
 310                 }
 311                 return mp;
 312         }
 313         return NULL;
 314 }
 315
 316 struct map_ent *map_by_name(struct map_ent **map, char *name)
 317 {
 318         struct map_ent *mp;
 319         if (!*map)
 320                 map_read(map);
 321
 322         for (mp = *map ; mp ; mp = mp->next) {
 323                 if (!mp->path)
 324                         continue;
 325                 if (strncmp(mp->path, DEV_MD_DIR, DEV_MD_DIR_LEN) != 0)
 326                         continue;
 327                 if (strcmp(mp->path + DEV_MD_DIR_LEN, name) != 0)
 328                         continue;
 329                 if (!mddev_busy(mp->devnm)) {
 330                         mp->bad = 1;
 331                         continue;
 332                 }
 333                 return mp;
 334         }
 335         return NULL;
 336 }
 337
 338 /* sets the proper subarray and container_dev according to the metadata
 339  * version super_by_fd does this automatically, this routine is meant as
 340  * a supplement for guess_super()
 341  */
 342 static char *get_member_info(struct mdstat_ent *ent)
 343 {
 344         char *subarray;
 345
 346         if (!is_mdstat_ent_subarray(ent))
 347                 return NULL;
 348
 349         subarray = strrchr(ent->metadata_version, '/');
 350
 351         return subarray + 1;
 352 }
 353
 354 void RebuildMap(void)
 355 {
 356         struct mdstat_ent *mdstat = mdstat_read(0, 0);
 357         struct mdstat_ent *md;
 358         struct map_ent *map = NULL;
 359         int require_homehost;
 360         char sys_hostname[256];
 361         char *homehost = conf_get_homehost(&require_homehost);
 362
 363         if (homehost == NULL || strcmp(homehost, "<system>")==0) {
 364                 if (s_gethostname(sys_hostname, sizeof(sys_hostname)) == 0) {
 365                         homehost = sys_hostname;
 366                 }
 367         }
 368
 369         for (md = mdstat ; md ; md = md->next) {
 370                 struct mdinfo *sra = sysfs_read(-1, md->devnm, GET_DEVS);
 371                 struct mdinfo *sd;
 372
 373                 if (!sra)
 374                         continue;
 375
 376                 for (sd = sra->devs ; sd ; sd = sd->next) {
 377                         char namebuf[100];
 378                         char dn[30];
 379                         int dfd;
 380                         int ok;
 381                         dev_t devid;
 382                         struct supertype *st;
 383                         char *subarray = NULL;
 384                         char *path;
 385                         struct mdinfo *info;
 386
 387                         sprintf(dn, "%d:%d", sd->disk.major, sd->disk.minor);
 388                         dfd = dev_open(dn, O_RDONLY);
 389                         if (dfd < 0)
 390                                 continue;
 391                         st = guess_super(dfd);
 392                         if ( st == NULL)
 393                                 ok = -1;
 394                         else {
 395                                 subarray = get_member_info(md);
 396                                 ok = st->ss->load_super(st, dfd, NULL);
 397                         }
 398                         close(dfd);
 399                         if (ok != 0)
 400                                 continue;
 401                         if (subarray)
 402                                 info = st->ss->container_content(st, subarray);
 403                         else {
 404                                 info = xmalloc(sizeof(*info));
 405                                 st->ss->getinfo_super(st, info, NULL);
 406                         }
 407                         if (!info)
 408                                 continue;
 409
 410                         devid = devnm2devid(md->devnm);
 411                         path = map_dev(major(devid), minor(devid), 0);
 412                         if (path == NULL ||
 413                             strncmp(path, DEV_MD_DIR, DEV_MD_DIR_LEN) != 0) {
 414                                 /* We would really like a name that provides
 415                                  * an MD_DEVNAME for udev.
 416                                  * The name needs to be unique both in /dev/md/
 417                                  * and in this mapfile.
 418                                  * It needs to match what -I or -As would come
 419                                  * up with.
 420                                  * That means:
 421                                  *   Check if array is in mdadm.conf
 422                                  *        - if so use that.
 423                                  *   determine trustworthy from homehost etc
 424                                  *   find a unique name based on metadata name.
 425                                  *
 426                                  */
 427                                 struct mddev_ident *match = conf_match(st, info,
 428                                                                        NULL, 0,
 429                                                                        NULL);
 430                                 struct stat stb;
 431                                 if (match && match->devname && match->devname[0] == '/') {
 432                                         path = match->devname;
 433                                         if (path[0] != '/') {
 434                                                 strcpy(namebuf, DEV_MD_DIR);
 435                                                 strcat(namebuf, path);
 436                                                 path = namebuf;
 437                                         }
 438                                 } else {
 439                                         int unum = 0;
 440                                         char *sep = "_";
 441                                         const char *name;
 442                                         int conflict = 1;
 443                                         if ((homehost == NULL ||
 444                                              st->ss->match_home(st, homehost) != 1) &&
 445                                             st->ss->match_home(st, "any") != 1 &&
 446                                             (require_homehost ||
 447                                              !conf_name_is_free(info->name)))
 448                                                 /* require a numeric suffix */
 449                                                 unum = 0;
 450                                         else
 451                                                 /* allow name to be used as-is if no conflict */
 452                                                 unum = -1;
 453                                         name = info->name;
 454                                         if (!*name) {
 455                                                 name = st->ss->name;
 456                                                 if (!isdigit(name[strlen(name)-1]) &&
 457                                                     unum == -1) {
 458                                                         unum = 0;
 459                                                         sep = "";
 460                                                 }
 461                                         }
 462                                         if (strchr(name, ':')) {
 463                                                 /* Probably a uniquifying
 464                                                  * hostname prefix.  Allow
 465                                                  * without a suffix, and strip
 466                                                  * hostname if it is us.
 467                                                  */
 468                                                 if (homehost && unum == -1 &&
 469                                                     strncmp(name, homehost,
 470                                                             strlen(homehost)) == 0 &&
 471                                                     name[strlen(homehost)] == ':')
 472                                                         name += strlen(homehost)+1;
 473                                                 unum = -1;
 474                                         }
 475
 476                                         while (conflict) {
 477                                                 if (unum >= 0)
 478                                                         sprintf(namebuf, DEV_MD_DIR "%s%s%d",
 479                                                                 name, sep, unum);
 480                                                 else
 481                                                         sprintf(namebuf, DEV_MD_DIR "%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->devnm,
 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->devnm,
 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 }