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_add(struct map_ent **melp,
 163             int devnum, char *metadata, int uuid[4], char *path)
 164 {
 165         struct map_ent *me = malloc(sizeof(*me));
 166
 167         me->devnum = devnum;
 168         strcpy(me->metadata, metadata);
 169         memcpy(me->uuid, uuid, 16);
 170         me->path = path ? strdup(path) : NULL;
 171         me->next = *melp;
 172         me->bad = 0;
 173         *melp = me;
 174 }
 175
 176 void map_read(struct map_ent **melp)
 177 {
 178         FILE *f;
 179         char buf[8192];
 180         char path[200];
 181         int devnum, uuid[4];
 182         char metadata[30];
 183         char nam[4];
 184
 185         *melp = NULL;
 186
 187         f = open_map(MAP_READ);
 188         if (!f) {
 189                 RebuildMap();
 190                 f = open_map(MAP_READ);
 191         }
 192         if (!f)
 193                 return;
 194
 195         while (fgets(buf, sizeof(buf), f)) {
 196                 path[0] = 0;
 197                 if (sscanf(buf, " %3[mdp]%d %s %x:%x:%x:%x %200s",
 198                            nam, &devnum, metadata, uuid, uuid+1,
 199                            uuid+2, uuid+3, path) >= 7) {
 200                         if (strncmp(nam, "md", 2) != 0)
 201                                 continue;
 202                         if (nam[2] == 'p')
 203                                 devnum = -1 - devnum;
 204                         map_add(melp, devnum, metadata, uuid, path);
 205                 }
 206         }
 207         fclose(f);
 208 }
 209
 210 void map_free(struct map_ent *map)
 211 {
 212         while (map) {
 213                 struct map_ent *mp = map;
 214                 map = mp->next;
 215                 free(mp->path);
 216                 free(mp);
 217         }
 218 }
 219
 220 int map_update(struct map_ent **mpp, int devnum, char *metadata,
 221                int *uuid, char *path)
 222 {
 223         struct map_ent *map, *mp;
 224         int rv;
 225
 226         if (mpp && *mpp)
 227                 map = *mpp;
 228         else
 229                 map_read(&map);
 230
 231         for (mp = map ; mp ; mp=mp->next)
 232                 if (mp->devnum == devnum) {
 233                         strcpy(mp->metadata, metadata);
 234                         memcpy(mp->uuid, uuid, 16);
 235                         free(mp->path);
 236                         mp->path = path ? strdup(path) : NULL;
 237                         break;
 238                 }
 239         if (!mp)
 240                 map_add(&map, devnum, 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, int devnum)
 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 (mp->devnum == devnum) {
 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, int devnum)
 266 {
 267         if (devnum == NoMdDev)
 268                 return;
 269
 270         map_delete(mapp, devnum);
 271         map_write(*mapp);
 272         map_free(*mapp);
 273 }
 274
 275 struct map_ent *map_by_uuid(struct map_ent **map, int uuid[4])
 276 {
 277         struct map_ent *mp;
 278         if (!*map)
 279                 map_read(map);
 280
 281         for (mp = *map ; mp ; mp = mp->next) {
 282                 if (memcmp(uuid, mp->uuid, 16) != 0)
 283                         continue;
 284                 if (!mddev_busy(mp->devnum)) {
 285                         mp->bad = 1;
 286                         continue;
 287                 }
 288                 return mp;
 289         }
 290         return NULL;
 291 }
 292
 293 struct map_ent *map_by_devnum(struct map_ent **map, int devnum)
 294 {
 295         struct map_ent *mp;
 296         if (!*map)
 297                 map_read(map);
 298
 299         for (mp = *map ; mp ; mp = mp->next) {
 300                 if (mp->devnum != devnum)
 301                         continue;
 302                 if (!mddev_busy(mp->devnum)) {
 303                         mp->bad = 1;
 304                         continue;
 305                 }
 306                 return mp;
 307         }
 308         return NULL;
 309 }
 310
 311 struct map_ent *map_by_name(struct map_ent **map, char *name)
 312 {
 313         struct map_ent *mp;
 314         if (!*map)
 315                 map_read(map);
 316
 317         for (mp = *map ; mp ; mp = mp->next) {
 318                 if (!mp->path)
 319                         continue;
 320                 if (strncmp(mp->path, "/dev/md/", 8) != 0)
 321                         continue;
 322                 if (strcmp(mp->path+8, name) != 0)
 323                         continue;
 324                 if (!mddev_busy(mp->devnum)) {
 325                         mp->bad = 1;
 326                         continue;
 327                 }
 328                 return mp;
 329         }
 330         return NULL;
 331 }
 332
 333 /* sets the proper subarray and container_dev according to the metadata
 334  * version super_by_fd does this automatically, this routine is meant as
 335  * a supplement for guess_super()
 336  */
 337 static char *get_member_info(struct mdstat_ent *ent)
 338 {
 339
 340         if (ent->metadata_version == NULL ||
 341             strncmp(ent->metadata_version, "external:", 9) != 0)
 342                 return NULL;
 343
 344         if (is_subarray(&ent->metadata_version[9])) {
 345                 char *subarray;
 346
 347                 subarray = strrchr(ent->metadata_version, '/');
 348                 return subarray + 1;
 349         }
 350         return NULL;
 351 }
 352
 353 void RebuildMap(void)
 354 {
 355         struct mdstat_ent *mdstat = mdstat_read(0, 0);
 356         struct mdstat_ent *md;
 357         struct map_ent *map = NULL;
 358         int mdp = get_mdp_major();
 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 (gethostname(sys_hostname, sizeof(sys_hostname)) == 0) {
 365                         sys_hostname[sizeof(sys_hostname)-1] = 0;
 366                         homehost = sys_hostname;
 367                 }
 368         }
 369
 370         for (md = mdstat ; md ; md = md->next) {
 371                 struct mdinfo *sra = sysfs_read(-1, md->devnum, GET_DEVS);
 372                 struct mdinfo *sd;
 373
 374                 if (!sra)
 375                         continue;
 376
 377                 for (sd = sra->devs ; sd ; sd = sd->next) {
 378                         char namebuf[100];
 379                         char dn[30];
 380                         int dfd;
 381                         int ok;
 382                         struct supertype *st;
 383                         char *subarray;
 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                         info = st->ss->container_content(st, subarray);
 402
 403                         if (md->devnum >= 0)
 404                                 path = map_dev(MD_MAJOR, md->devnum, 0);
 405                         else
 406                                 path = map_dev(mdp, (-1-md->devnum)<< 6, 0);
 407                         if (path == NULL ||
 408                             strncmp(path, "/dev/md/", 8) != 0) {
 409                                 /* We would really like a name that provides
 410                                  * an MD_DEVNAME for udev.
 411                                  * The name needs to be unique both in /dev/md/
 412                                  * and in this mapfile.
 413                                  * It needs to match watch -I or -As would come
 414                                  * up with.
 415                                  * That means:
 416                                  *   Check if array is in mdadm.conf
 417                                  *        - if so use that.
 418                                  *   determine trustworthy from homehost etc
 419                                  *   find a unique name based on metadata name.
 420                                  *
 421                                  */
 422                                 struct mddev_ident *match = conf_match(info, st);
 423                                 struct stat stb;
 424                                 if (match && match->devname && match->devname[0] == '/') {
 425                                         path = match->devname;
 426                                         if (path[0] != '/') {
 427                                                 strcpy(namebuf, "/dev/md/");
 428                                                 strcat(namebuf, path);
 429                                                 path = namebuf;
 430                                         }
 431                                 } else {
 432                                         int unum = 0;
 433                                         char *sep = "_";
 434                                         const char *name;
 435                                         int conflict = 1;
 436                                         if ((homehost == NULL ||
 437                                              st->ss->match_home(st, homehost) != 1) &&
 438                                             st->ss->match_home(st, "any") != 1 &&
 439                                             (require_homehost
 440                                              || ! conf_name_is_free(info->name)))
 441                                                 /* require a numeric suffix */
 442                                                 unum = 0;
 443                                         else
 444                                                 /* allow name to be used as-is if no conflict */
 445                                                 unum = -1;
 446                                         name = info->name;
 447                                         if (!*name) {
 448                                                 name = st->ss->name;
 449                                                 if (!isdigit(name[strlen(name)-1]) &&
 450                                                     unum == -1) {
 451                                                         unum = 0;
 452                                                         sep = "";
 453                                                 }
 454                                         }
 455                                         if (strchr(name, ':'))
 456                                                 /* probably a uniquifying
 457                                                  * hostname prefix.  Allow
 458                                                  * without a suffix
 459                                                  */
 460                                                 unum = -1;
 461
 462                                         while (conflict) {
 463                                                 if (unum >= 0)
 464                                                         sprintf(namebuf, "/dev/md/%s%s%d",
 465                                                                 name, sep, unum);
 466                                                 else
 467                                                         sprintf(namebuf, "/dev/md/%s",
 468                                                                 name);
 469                                                 unum++;
 470                                                 if (lstat(namebuf, &stb) != 0 &&
 471                                                     (map == NULL ||
 472                                                      !map_by_name(&map, namebuf+8)))
 473                                                         conflict = 0;
 474                                         }
 475                                         path = namebuf;
 476                                 }
 477                         }
 478                         map_add(&map, md->devnum,
 479                                 info->text_version,
 480                                 info->uuid, path);
 481                         st->ss->free_super(st);
 482                         free(info);
 483                         break;
 484                 }
 485                 sysfs_free(sra);
 486         }
 487         /* Only trigger a change if we wrote a new map file */
 488         if (map_write(map))
 489                 for (md = mdstat ; md ; md = md->next) {
 490                         struct mdinfo *sra = sysfs_read(-1, md->devnum,
 491                                                         GET_VERSION);
 492                         if (sra)
 493                                 sysfs_uevent(sra, "change");
 494                         sysfs_free(sra);
 495                 }
 496         map_free(map);
 497         free_mdstat(mdstat);
 498 }