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 #define MAP_READ 0
  50 #define MAP_NEW 1
  51 #define MAP_LOCK 2
  52 #define MAP_DIRNAME 3
  53
  54 char *mapname[4] = {
  55         MAP_DIR "/" MAP_FILE,
  56         MAP_DIR "/" MAP_FILE ".new",
  57         MAP_DIR "/" MAP_FILE ".lock",
  58         MAP_DIR
  59 };
  60
  61 int mapmode[3] = { O_RDONLY, O_RDWR|O_CREAT, O_RDWR|O_CREAT|O_TRUNC };
  62 char *mapsmode[3] = { "r", "w", "w"};
  63
  64 FILE *open_map(int modenum)
  65 {
  66         int fd;
  67         if ((mapmode[modenum] & O_CREAT))
  68                 /* Attempt to create directory, don't worry about
  69                  * failure.
  70                  */
  71                 (void)mkdir(mapname[MAP_DIRNAME], 0755);
  72         fd = open(mapname[modenum], mapmode[modenum], 0600);
  73         if (fd >= 0)
  74                 return fdopen(fd, mapsmode[modenum]);
  75         return NULL;
  76 }
  77
  78 int map_write(struct map_ent *mel)
  79 {
  80         FILE *f;
  81         int err;
  82
  83         f = open_map(MAP_NEW);
  84
  85         if (!f)
  86                 return 0;
  87         for (; mel; mel = mel->next) {
  88                 if (mel->bad)
  89                         continue;
  90                 fprintf(f, "%s ", mel->devnm);
  91                 fprintf(f, "%s ", mel->metadata);
  92                 fprintf(f, "%08x:%08x:%08x:%08x ", mel->uuid[0],
  93                         mel->uuid[1], mel->uuid[2], mel->uuid[3]);
  94                 fprintf(f, "%s\n", mel->path?:"");
  95         }
  96         fflush(f);
  97         err = ferror(f);
  98         fclose(f);
  99         if (err) {
 100                 unlink(mapname[1]);
 101                 return 0;
 102         }
 103         return rename(mapname[1],
 104                       mapname[0]) == 0;
 105 }
 106
 107 static FILE *lf = NULL;
 108 int map_lock(struct map_ent **melp)
 109 {
 110         while (lf == NULL) {
 111                 struct stat buf;
 112                 lf = open_map(MAP_LOCK);
 113                 if (lf == NULL)
 114                         return -1;
 115                 if (flock(fileno(lf), LOCK_EX) != 0) {
 116                         fclose(lf);
 117                         lf = NULL;
 118                         return -1;
 119                 }
 120                 if (fstat(fileno(lf), &buf) != 0 ||
 121                     buf.st_nlink == 0) {
 122                         /* The owner of the lock unlinked it,
 123                          * so we have a lock on a stale file,
 124                          * try again
 125                          */
 126                         fclose(lf);
 127                         lf = NULL;
 128                 }
 129         }
 130         if (*melp)
 131                 map_free(*melp);
 132         map_read(melp);
 133         return 0;
 134 }
 135
 136 void map_unlock(struct map_ent **melp)
 137 {
 138         if (lf) {
 139                 /* must unlink before closing the file,
 140                  * as only the owner of the lock may
 141                  * unlink the file
 142                  */
 143                 unlink(mapname[2]);
 144                 fclose(lf);
 145         }
 146         lf = NULL;
 147 }
 148
 149 void map_fork(void)
 150 {
 151         /* We are forking, so must close the lock file.
 152          * Don't risk flushing anything though.
 153          */
 154         if (lf) {
 155                 close(fileno(lf));
 156                 fclose(lf);
 157                 lf = NULL;
 158         }
 159 }
 160
 161 void map_add(struct map_ent **melp,
 162              char * devnm, char *metadata, int uuid[4], char *path)
 163 {
 164         struct map_ent *me = xmalloc(sizeof(*me));
 165
 166         strcpy(me->devnm, devnm);
 167         strcpy(me->metadata, metadata);
 168         memcpy(me->uuid, uuid, 16);
 169         me->path = path ? xstrdup(path) : NULL;
 170         me->next = *melp;
 171         me->bad = 0;
 172         *melp = me;
 173 }
 174
 175 void map_read(struct map_ent **melp)
 176 {
 177         FILE *f;
 178         char buf[8192];
 179         char path[201];
 180         int uuid[4];
 181         char devnm[32];
 182         char metadata[30];
 183
 184         *melp = NULL;
 185
 186         f = open_map(MAP_READ);
 187         if (!f) {
 188                 RebuildMap();
 189                 f = open_map(MAP_READ);
 190         }
 191         if (!f)
 192                 return;
 193
 194         while (fgets(buf, sizeof(buf), f)) {
 195                 path[0] = 0;
 196                 if (sscanf(buf, " %s %s %x:%x:%x:%x %200s",
 197                            devnm, metadata, uuid, uuid+1,
 198                            uuid+2, uuid+3, path) >= 7) {
 199                         map_add(melp, devnm, metadata, uuid, path);
 200                 }
 201         }
 202         fclose(f);
 203 }
 204
 205 void map_free(struct map_ent *map)
 206 {
 207         while (map) {
 208                 struct map_ent *mp = map;
 209                 map = mp->next;
 210                 free(mp->path);
 211                 free(mp);
 212         }
 213 }
 214
 215 int map_update(struct map_ent **mpp, char *devnm, char *metadata,
 216                int *uuid, char *path)
 217 {
 218         struct map_ent *map, *mp;
 219         int rv;
 220
 221         if (mpp && *mpp)
 222                 map = *mpp;
 223         else
 224                 map_read(&map);
 225
 226         for (mp = map ; mp ; mp=mp->next)
 227                 if (strcmp(mp->devnm, devnm) == 0) {
 228                         strcpy(mp->metadata, metadata);
 229                         memcpy(mp->uuid, uuid, 16);
 230                         free(mp->path);
 231                         mp->path = path ? xstrdup(path) : NULL;
 232                         mp->bad = 0;
 233                         break;
 234                 }
 235         if (!mp)
 236                 map_add(&map, devnm, metadata, uuid, path);
 237         if (mpp)
 238                 *mpp = NULL;
 239         rv = map_write(map);
 240         map_free(map);
 241         return rv;
 242 }
 243
 244 void map_delete(struct map_ent **mapp, char *devnm)
 245 {
 246         struct map_ent *mp;
 247
 248         if (*mapp == NULL)
 249                 map_read(mapp);
 250
 251         for (mp = *mapp; mp; mp = *mapp) {
 252                 if (strcmp(mp->devnm, devnm) == 0) {
 253                         *mapp = mp->next;
 254                         free(mp->path);
 255                         free(mp);
 256                 } else
 257                         mapp = & mp->next;
 258         }
 259 }
 260
 261 void map_remove(struct map_ent **mapp, char *devnm)
 262 {
 263         if (devnm[0] == 0)
 264                 return;
 265
 266         map_delete(mapp, devnm);
 267         map_write(*mapp);
 268         map_free(*mapp);
 269 }
 270
 271 struct map_ent *map_by_uuid(struct map_ent **map, int uuid[4])
 272 {
 273         struct map_ent *mp;
 274         if (!*map)
 275                 map_read(map);
 276
 277         for (mp = *map ; mp ; mp = mp->next) {
 278                 if (memcmp(uuid, mp->uuid, 16) != 0)
 279                         continue;
 280                 if (!mddev_busy(mp->devnm)) {
 281                         mp->bad = 1;
 282                         continue;
 283                 }
 284                 return mp;
 285         }
 286         return NULL;
 287 }
 288
 289 struct map_ent *map_by_devnm(struct map_ent **map, char *devnm)
 290 {
 291         struct map_ent *mp;
 292         if (!*map)
 293                 map_read(map);
 294
 295         for (mp = *map ; mp ; mp = mp->next) {
 296                 if (strcmp(mp->devnm, devnm) != 0)
 297                         continue;
 298                 if (!mddev_busy(mp->devnm)) {
 299                         mp->bad = 1;
 300                         continue;
 301                 }
 302                 return mp;
 303         }
 304         return NULL;
 305 }
 306
 307 struct map_ent *map_by_name(struct map_ent **map, char *name)
 308 {
 309         struct map_ent *mp;
 310         if (!*map)
 311                 map_read(map);
 312
 313         for (mp = *map ; mp ; mp = mp->next) {
 314                 if (!mp->path)
 315                         continue;
 316                 if (strncmp(mp->path, "/dev/md/", 8) != 0)
 317                         continue;
 318                 if (strcmp(mp->path+8, name) != 0)
 319                         continue;
 320                 if (!mddev_busy(mp->devnm)) {
 321                         mp->bad = 1;
 322                         continue;
 323                 }
 324                 return mp;
 325         }
 326         return NULL;
 327 }
 328
 329 /* sets the proper subarray and container_dev according to the metadata
 330  * version super_by_fd does this automatically, this routine is meant as
 331  * a supplement for guess_super()
 332  */
 333 static char *get_member_info(struct mdstat_ent *ent)
 334 {
 335
 336         if (ent->metadata_version == NULL ||
 337             strncmp(ent->metadata_version, "external:", 9) != 0)
 338                 return NULL;
 339
 340         if (is_subarray(&ent->metadata_version[9])) {
 341                 char *subarray;
 342
 343                 subarray = strrchr(ent->metadata_version, '/');
 344                 return subarray + 1;
 345         }
 346         return NULL;
 347 }
 348
 349 void RebuildMap(void)
 350 {
 351         struct mdstat_ent *mdstat = mdstat_read(0, 0);
 352         struct mdstat_ent *md;
 353         struct map_ent *map = NULL;
 354         int require_homehost;
 355         char sys_hostname[256];
 356         char *homehost = conf_get_homehost(&require_homehost);
 357
 358         if (homehost == NULL || strcmp(homehost, "<system>")==0) {
 359                 if (gethostname(sys_hostname, sizeof(sys_hostname)) == 0) {
 360                         sys_hostname[sizeof(sys_hostname)-1] = 0;
 361                         homehost = sys_hostname;
 362                 }
 363         }
 364
 365         for (md = mdstat ; md ; md = md->next) {
 366                 struct mdinfo *sra = sysfs_read(-1, md->devnm, GET_DEVS);
 367                 struct mdinfo *sd;
 368
 369                 if (!sra)
 370                         continue;
 371
 372                 for (sd = sra->devs ; sd ; sd = sd->next) {
 373                         char namebuf[100];
 374                         char dn[30];
 375                         int dfd;
 376                         int ok;
 377                         dev_t devid;
 378                         struct supertype *st;
 379                         char *subarray = NULL;
 380                         char *path;
 381                         struct mdinfo *info;
 382
 383                         sprintf(dn, "%d:%d", sd->disk.major, sd->disk.minor);
 384                         dfd = dev_open(dn, O_RDONLY);
 385                         if (dfd < 0)
 386                                 continue;
 387                         st = guess_super(dfd);
 388                         if ( st == NULL)
 389                                 ok = -1;
 390                         else {
 391                                 subarray = get_member_info(md);
 392                                 ok = st->ss->load_super(st, dfd, NULL);
 393                         }
 394                         close(dfd);
 395                         if (ok != 0)
 396                                 continue;
 397                         if (subarray)
 398                                 info = st->ss->container_content(st, subarray);
 399                         else {
 400                                 info = xmalloc(sizeof(*info));
 401                                 st->ss->getinfo_super(st, info, NULL);
 402                         }
 403                         if (!info)
 404                                 continue;
 405
 406                         devid = devnm2devid(md->devnm);
 407                         path = map_dev(major(devid), minor(devid), 0);
 408                         if (path == NULL ||
 409                             strncmp(path, "/dev/md/", 8) != 0) {
 410                                 /* We would really like a name that provides
 411                                  * an MD_DEVNAME for udev.
 412                                  * The name needs to be unique both in /dev/md/
 413                                  * and in this mapfile.
 414                                  * It needs to match what -I or -As would come
 415                                  * up with.
 416                                  * That means:
 417                                  *   Check if array is in mdadm.conf
 418                                  *        - if so use that.
 419                                  *   determine trustworthy from homehost etc
 420                                  *   find a unique name based on metadata name.
 421                                  *
 422                                  */
 423                                 struct mddev_ident *match = conf_match(st, info,
 424                                                                        NULL, 0,
 425                                                                        NULL);
 426                                 struct stat stb;
 427                                 if (match && match->devname && match->devname[0] == '/') {
 428                                         path = match->devname;
 429                                         if (path[0] != '/') {
 430                                                 strcpy(namebuf, "/dev/md/");
 431                                                 strcat(namebuf, path);
 432                                                 path = namebuf;
 433                                         }
 434                                 } else {
 435                                         int unum = 0;
 436                                         char *sep = "_";
 437                                         const char *name;
 438                                         int conflict = 1;
 439                                         if ((homehost == NULL ||
 440                                              st->ss->match_home(st, homehost) != 1) &&
 441                                             st->ss->match_home(st, "any") != 1 &&
 442                                             (require_homehost
 443                                              || ! conf_name_is_free(info->name)))
 444                                                 /* require a numeric suffix */
 445                                                 unum = 0;
 446                                         else
 447                                                 /* allow name to be used as-is if no conflict */
 448                                                 unum = -1;
 449                                         name = info->name;
 450                                         if (!*name) {
 451                                                 name = st->ss->name;
 452                                                 if (!isdigit(name[strlen(name)-1]) &&
 453                                                     unum == -1) {
 454                                                         unum = 0;
 455                                                         sep = "";
 456                                                 }
 457                                         }
 458                                         if (strchr(name, ':')) {
 459                                                 /* Probably a uniquifying
 460                                                  * hostname prefix.  Allow
 461                                                  * without a suffix, and strip
 462                                                  * hostname if it is us.
 463                                                  */
 464                                                 if (homehost && unum == -1 &&
 465                                                     strncmp(name, homehost,
 466                                                             strlen(homehost)) == 0 &&
 467                                                     name[strlen(homehost)] == ':')
 468                                                         name += strlen(homehost)+1;
 469                                                 unum = -1;
 470                                         }
 471
 472                                         while (conflict) {
 473                                                 if (unum >= 0)
 474                                                         sprintf(namebuf, "/dev/md/%s%s%d",
 475                                                                 name, sep, unum);
 476                                                 else
 477                                                         sprintf(namebuf, "/dev/md/%s",
 478                                                                 name);
 479                                                 unum++;
 480                                                 if (lstat(namebuf, &stb) != 0 &&
 481                                                     (map == NULL ||
 482                                                      !map_by_name(&map, namebuf+8)))
 483                                                         conflict = 0;
 484                                         }
 485                                         path = namebuf;
 486                                 }
 487                         }
 488                         map_add(&map, md->devnm,
 489                                 info->text_version,
 490                                 info->uuid, path);
 491                         st->ss->free_super(st);
 492                         free(info);
 493                         break;
 494                 }
 495                 sysfs_free(sra);
 496         }
 497         /* Only trigger a change if we wrote a new map file */
 498         if (map_write(map))
 499                 for (md = mdstat ; md ; md = md->next) {
 500                         struct mdinfo *sra = sysfs_read(-1, md->devnm,
 501                                                         GET_VERSION);
 502                         if (sra)
 503                                 sysfs_uevent(sra, "change");
 504                         sysfs_free(sra);
 505                 }
 506         map_free(map);
 507         free_mdstat(mdstat);
 508 }