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        <sys/file.h>
  47 #include        <ctype.h>
  48
  49
  50 #define MAP_READ 0
  51 #define MAP_NEW 1
  52 #define MAP_LOCK 2
  53 #define MAP_DIRNAME 3
  54
  55 char *mapname[4] = {
  56         MAP_DIR "/" MAP_FILE,
  57         MAP_DIR "/" MAP_FILE ".new",
  58         MAP_DIR "/" MAP_FILE ".lock",
  59         MAP_DIR
  60 };
  61
  62 int mapmode[3] = { O_RDONLY, O_RDWR|O_CREAT, O_RDWR|O_CREAT|O_TRUNC };
  63 char *mapsmode[3] = { "r", "w", "w"};
  64
  65 FILE *open_map(int modenum)
  66 {
  67         int fd;
  68         if ((mapmode[modenum] & O_CREAT))
  69                 /* Attempt to create directory, don't worry about
  70                  * failure.
  71                  */
  72                 (void)mkdir(mapname[MAP_DIRNAME], 0755);
  73         fd = open(mapname[modenum], mapmode[modenum], 0600);
  74         if (fd >= 0)
  75                 return fdopen(fd, mapsmode[modenum]);
  76         return NULL;
  77 }
  78
  79 int map_write(struct map_ent *mel)
  80 {
  81         FILE *f;
  82         int err;
  83
  84         f = open_map(MAP_NEW);
  85
  86         if (!f)
  87                 return 0;
  88         for (; mel; mel = mel->next) {
  89                 if (mel->bad)
  90                         continue;
  91                 if (mel->devnum < 0)
  92                         fprintf(f, "mdp%d ", -1-mel->devnum);
  93                 else
  94                         fprintf(f, "md%d ", mel->devnum);
  95                 fprintf(f, "%s ", mel->metadata);
  96                 fprintf(f, "%08x:%08x:%08x:%08x ", mel->uuid[0],
  97                         mel->uuid[1], mel->uuid[2], mel->uuid[3]);
  98                 fprintf(f, "%s\n", mel->path?:"");
  99         }
 100         fflush(f);
 101         err = ferror(f);
 102         fclose(f);
 103         if (err) {
 104                 unlink(mapname[1]);
 105                 return 0;
 106         }
 107         return rename(mapname[1],
 108                       mapname[0]) == 0;
 109 }
 110
 111
 112 static FILE *lf = NULL;
 113 int map_lock(struct map_ent **melp)
 114 {
 115         while (lf == NULL) {
 116                 struct stat buf;
 117                 lf = open_map(MAP_LOCK);
 118                 if (lf == NULL)
 119                         return -1;
 120                 if (flock(fileno(lf), LOCK_EX) != 0) {
 121                         fclose(lf);
 122                         lf = NULL;
 123                         return -1;
 124                 }
 125                 if (fstat(fileno(lf), &buf) != 0 ||
 126                     buf.st_nlink == 0) {
 127                         /* The owner of the lock unlinked it,
 128                          * so we have a lock on a stale file,
 129                          * try again
 130                          */
 131                         fclose(lf);
 132                         lf = NULL;
 133                 }
 134         }
 135         if (*melp)
 136                 map_free(*melp);
 137         map_read(melp);
 138         return 0;
 139 }
 140
 141 void map_unlock(struct map_ent **melp)
 142 {
 143         if (lf) {
 144                 /* must unlink before closing the file,
 145                  * as only the owner of the lock may
 146                  * unlink the file
 147                  */
 148                 unlink(mapname[2]);
 149                 fclose(lf);
 150         }
 151         lf = NULL;
 152 }
 153
 154 void map_fork(void)
 155 {
 156         /* We are forking, so must close the lock file.
 157          * Don't risk flushing anything though.
 158          */
 159         if (lf) {
 160                 close(fileno(lf));
 161                 fclose(lf);
 162                 lf = NULL;
 163         }
 164 }
 165
 166 void map_add(struct map_ent **melp,
 167             int devnum, char *metadata, int uuid[4], char *path)
 168 {
 169         struct map_ent *me = malloc(sizeof(*me));
 170
 171         me->devnum = devnum;
 172         strcpy(me->metadata, metadata);
 173         memcpy(me->uuid, uuid, 16);
 174         me->path = path ? strdup(path) : NULL;
 175         me->next = *melp;
 176         me->bad = 0;
 177         *melp = me;
 178 }
 179
 180 void map_read(struct map_ent **melp)
 181 {
 182         FILE *f;
 183         char buf[8192];
 184         char path[200];
 185         int devnum, uuid[4];
 186         char metadata[30];
 187         char nam[4];
 188
 189         *melp = NULL;
 190
 191         f = open_map(MAP_READ);
 192         if (!f) {
 193                 RebuildMap();
 194                 f = open_map(MAP_READ);
 195         }
 196         if (!f)
 197                 return;
 198
 199         while (fgets(buf, sizeof(buf), f)) {
 200                 path[0] = 0;
 201                 if (sscanf(buf, " %3[mdp]%d %s %x:%x:%x:%x %200s",
 202                            nam, &devnum, metadata, uuid, uuid+1,
 203                            uuid+2, uuid+3, path) >= 7) {
 204                         if (strncmp(nam, "md", 2) != 0)
 205                                 continue;
 206                         if (nam[2] == 'p')
 207                                 devnum = -1 - devnum;
 208                         map_add(melp, devnum, metadata, uuid, path);
 209                 }
 210         }
 211         fclose(f);
 212 }
 213
 214 void map_free(struct map_ent *map)
 215 {
 216         while (map) {
 217                 struct map_ent *mp = map;
 218                 map = mp->next;
 219                 free(mp->path);
 220                 free(mp);
 221         }
 222 }
 223
 224 int map_update(struct map_ent **mpp, int devnum, char *metadata,
 225                int *uuid, char *path)
 226 {
 227         struct map_ent *map, *mp;
 228         int rv;
 229
 230         if (mpp && *mpp)
 231                 map = *mpp;
 232         else
 233                 map_read(&map);
 234
 235         for (mp = map ; mp ; mp=mp->next)
 236                 if (mp->devnum == devnum) {
 237                         strcpy(mp->metadata, metadata);
 238                         memcpy(mp->uuid, uuid, 16);
 239                         free(mp->path);
 240                         mp->path = path ? strdup(path) : NULL;
 241                         mp->bad = 0;
 242                         break;
 243                 }
 244         if (!mp)
 245                 map_add(&map, devnum, metadata, uuid, path);
 246         if (mpp)
 247                 *mpp = NULL;
 248         rv = map_write(map);
 249         map_free(map);
 250         return rv;
 251 }
 252
 253 void map_delete(struct map_ent **mapp, int devnum)
 254 {
 255         struct map_ent *mp;
 256
 257         if (*mapp == NULL)
 258                 map_read(mapp);
 259
 260         for (mp = *mapp; mp; mp = *mapp) {
 261                 if (mp->devnum == devnum) {
 262                         *mapp = mp->next;
 263                         free(mp->path);
 264                         free(mp);
 265                 } else
 266                         mapp = & mp->next;
 267         }
 268 }
 269
 270 void map_remove(struct map_ent **mapp, int devnum)
 271 {
 272         if (devnum == NoMdDev)
 273                 return;
 274
 275         map_delete(mapp, devnum);
 276         map_write(*mapp);
 277         map_free(*mapp);
 278 }
 279
 280 struct map_ent *map_by_uuid(struct map_ent **map, int uuid[4])
 281 {
 282         struct map_ent *mp;
 283         if (!*map)
 284                 map_read(map);
 285
 286         for (mp = *map ; mp ; mp = mp->next) {
 287                 if (memcmp(uuid, mp->uuid, 16) != 0)
 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_devnum(struct map_ent **map, int devnum)
 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->devnum != devnum)
 306                         continue;
 307                 if (!mddev_busy(mp->devnum)) {
 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/", 8) != 0)
 326                         continue;
 327                 if (strcmp(mp->path+8, name) != 0)
 328                         continue;
 329                 if (!mddev_busy(mp->devnum)) {
 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
 345         if (ent->metadata_version == NULL ||
 346             strncmp(ent->metadata_version, "external:", 9) != 0)
 347                 return NULL;
 348
 349         if (is_subarray(&ent->metadata_version[9])) {
 350                 char *subarray;
 351
 352                 subarray = strrchr(ent->metadata_version, '/');
 353                 return subarray + 1;
 354         }
 355         return NULL;
 356 }
 357
 358 void RebuildMap(void)
 359 {
 360         struct mdstat_ent *mdstat = mdstat_read(0, 0);
 361         struct mdstat_ent *md;
 362         struct map_ent *map = NULL;
 363         int mdp = get_mdp_major();
 364         int require_homehost;
 365         char sys_hostname[256];
 366         char *homehost = conf_get_homehost(&require_homehost);
 367
 368         if (homehost == NULL || strcmp(homehost, "<system>")==0) {
 369                 if (gethostname(sys_hostname, sizeof(sys_hostname)) == 0) {
 370                         sys_hostname[sizeof(sys_hostname)-1] = 0;
 371                         homehost = sys_hostname;
 372                 }
 373         }
 374
 375         for (md = mdstat ; md ; md = md->next) {
 376                 struct mdinfo *sra = sysfs_read(-1, md->devnum, GET_DEVS);
 377                 struct mdinfo *sd;
 378
 379                 if (!sra)
 380                         continue;
 381
 382                 for (sd = sra->devs ; sd ; sd = sd->next) {
 383                         char namebuf[100];
 384                         char dn[30];
 385                         int dfd;
 386                         int ok;
 387                         struct supertype *st;
 388                         char *subarray = NULL;
 389                         char *path;
 390                         struct mdinfo *info;
 391
 392                         sprintf(dn, "%d:%d", sd->disk.major, sd->disk.minor);
 393                         dfd = dev_open(dn, O_RDONLY);
 394                         if (dfd < 0)
 395                                 continue;
 396                         st = guess_super(dfd);
 397                         if ( st == NULL)
 398                                 ok = -1;
 399                         else {
 400                                 subarray = get_member_info(md);
 401                                 ok = st->ss->load_super(st, dfd, NULL);
 402                         }
 403                         close(dfd);
 404                         if (ok != 0)
 405                                 continue;
 406                         if (subarray)
 407                                 info = st->ss->container_content(st, subarray);
 408                         else {
 409                                 info = malloc(sizeof(*info));
 410                                 st->ss->getinfo_super(st, info, NULL);
 411                         }
 412                         if (!info)
 413                                 continue;
 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 what -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 }