mapfile.c

   1 /*
   2  * mapfile - manage /var/run/mdadm.map. Part of:
   3  * mdadm - manage Linux "md" devices aka RAID arrays.
   4  *
   5  * Copyright (C) 2006-2009 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 /* /var/run/mdadm.map 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 preferred location for the map file is /var/run/mdadm.map.
  42  * However /var/run may not exist or be writable in early boot.  And if
  43  * no-one has created /var/run/mdadm, we still want to survive.
  44  * So possible locations are:
  45  *   /var/run/mdadm/map  /var/run/mdadm.map  /lib/initrw/madam/map
  46  * The last can easily be change at compile to e.g. somewhere in /dev.
  47  * We read from the first one that exists and write to the first
  48  * one that we can.
  49  */
  50 #include        "mdadm.h"
  51 #include        <sys/file.h>
  52 #include        <ctype.h>
  53
  54 #define mapnames(base) { base, base ".new", base ".lock"}
  55 char *mapname[3][3] = {
  56         mapnames(VAR_RUN "/map"),
  57         mapnames("/var/run/mdadm.map"),
  58         mapnames(ALT_RUN "/" ALT_MAPFILE)
  59 };
  60 char *mapdir[3] = { VAR_RUN, NULL, ALT_RUN };
  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, int *choice)
  66 {
  67         int i;
  68
  69         for (i = 0 ; i < 3 ; i++) {
  70                 int fd;
  71                 if ((mapmode[modenum] & O_CREAT) &&
  72                     mapdir[modenum])
  73                         /* Attempt to create directory, don't worry about
  74                          * failure.
  75                          */
  76                         mkdir(mapdir[modenum], 0755);
  77                 fd = open(mapname[i][modenum], mapmode[modenum], 0600);
  78                 if (fd >= 0) {
  79                         *choice = i;
  80                         return fdopen(fd, mapsmode[modenum]);
  81                 }
  82         }
  83         return NULL;
  84 }
  85
  86 int map_write(struct map_ent *mel)
  87 {
  88         FILE *f;
  89         int err;
  90         int which;
  91
  92         f = open_map(1, &which);
  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[which][1]);
 113                 return 0;
 114         }
 115         return rename(mapname[which][1],
 116                       mapname[which][0]) == 0;
 117 }
 118
 119
 120 static FILE *lf = NULL;
 121 static int lwhich = 0;
 122 int map_lock(struct map_ent **melp)
 123 {
 124         if (lf == NULL) {
 125                 lf = open_map(2, &lwhich);
 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         }
 134         if (*melp)
 135                 map_free(*melp);
 136         map_read(melp);
 137         return 0;
 138 }
 139
 140 void map_unlock(struct map_ent **melp)
 141 {
 142         if (lf) {
 143                 flock(fileno(lf), LOCK_UN);
 144                 fclose(lf);
 145         }
 146         unlink(mapname[lwhich][2]);
 147         lf = NULL;
 148 }
 149
 150 void map_add(struct map_ent **melp,
 151             int devnum, char *metadata, int uuid[4], char *path)
 152 {
 153         struct map_ent *me = malloc(sizeof(*me));
 154
 155         me->devnum = devnum;
 156         strcpy(me->metadata, metadata);
 157         memcpy(me->uuid, uuid, 16);
 158         me->path = path ? strdup(path) : NULL;
 159         me->next = *melp;
 160         me->bad = 0;
 161         *melp = me;
 162 }
 163
 164 void map_read(struct map_ent **melp)
 165 {
 166         FILE *f;
 167         char buf[8192];
 168         char path[200];
 169         int devnum, uuid[4];
 170         char metadata[30];
 171         char nam[4];
 172         int which;
 173
 174         *melp = NULL;
 175
 176         f = open_map(0, &which);
 177         if (!f) {
 178                 RebuildMap();
 179                 f = open_map(0, &which);
 180         }
 181         if (!f)
 182                 return;
 183
 184         while (fgets(buf, sizeof(buf), f)) {
 185                 path[0] = 0;
 186                 if (sscanf(buf, " %3[mdp]%d %s %x:%x:%x:%x %200s",
 187                            nam, &devnum, metadata, uuid, uuid+1,
 188                            uuid+2, uuid+3, path) >= 7) {
 189                         if (strncmp(nam, "md", 2) != 0)
 190                                 continue;
 191                         if (nam[2] == 'p')
 192                                 devnum = -1 - devnum;
 193                         map_add(melp, devnum, metadata, uuid, path);
 194                 }
 195         }
 196         fclose(f);
 197 }
 198
 199 void map_free(struct map_ent *map)
 200 {
 201         while (map) {
 202                 struct map_ent *mp = map;
 203                 map = mp->next;
 204                 free(mp->path);
 205                 free(mp);
 206         }
 207 }
 208
 209 int map_update(struct map_ent **mpp, int devnum, char *metadata,
 210                int *uuid, char *path)
 211 {
 212         struct map_ent *map, *mp;
 213         int rv;
 214
 215         if (mpp && *mpp)
 216                 map = *mpp;
 217         else
 218                 map_read(&map);
 219
 220         for (mp = map ; mp ; mp=mp->next)
 221                 if (mp->devnum == devnum) {
 222                         strcpy(mp->metadata, metadata);
 223                         memcpy(mp->uuid, uuid, 16);
 224                         free(mp->path);
 225                         mp->path = path ? strdup(path) : NULL;
 226                         break;
 227                 }
 228         if (!mp)
 229                 map_add(&map, devnum, metadata, uuid, path);
 230         if (mpp)
 231                 *mpp = NULL;
 232         rv = map_write(map);
 233         map_free(map);
 234         return rv;
 235 }
 236
 237 void map_delete(struct map_ent **mapp, int devnum)
 238 {
 239         struct map_ent *mp;
 240
 241         if (*mapp == NULL)
 242                 map_read(mapp);
 243
 244         for (mp = *mapp; mp; mp = *mapp) {
 245                 if (mp->devnum == devnum) {
 246                         *mapp = mp->next;
 247                         free(mp->path);
 248                         free(mp);
 249                 } else
 250                         mapp = & mp->next;
 251         }
 252 }
 253
 254 struct map_ent *map_by_uuid(struct map_ent **map, int uuid[4])
 255 {
 256         struct map_ent *mp;
 257         if (!*map)
 258                 map_read(map);
 259
 260         for (mp = *map ; mp ; mp = mp->next) {
 261                 if (memcmp(uuid, mp->uuid, 16) != 0)
 262                         continue;
 263                 if (!mddev_busy(mp->devnum)) {
 264                         mp->bad = 1;
 265                         continue;
 266                 }
 267                 return mp;
 268         }
 269         return NULL;
 270 }
 271
 272 struct map_ent *map_by_devnum(struct map_ent **map, int devnum)
 273 {
 274         struct map_ent *mp;
 275         if (!*map)
 276                 map_read(map);
 277
 278         for (mp = *map ; mp ; mp = mp->next) {
 279                 if (mp->devnum != devnum)
 280                         continue;
 281                 if (!mddev_busy(mp->devnum)) {
 282                         mp->bad = 1;
 283                         continue;
 284                 }
 285                 return mp;
 286         }
 287         return NULL;
 288 }
 289
 290 struct map_ent *map_by_name(struct map_ent **map, char *name)
 291 {
 292         struct map_ent *mp;
 293         if (!*map)
 294                 map_read(map);
 295
 296         for (mp = *map ; mp ; mp = mp->next) {
 297                 if (!mp->path)
 298                         continue;
 299                 if (strncmp(mp->path, "/dev/md/", 8) != 0)
 300                         continue;
 301                 if (strcmp(mp->path+8, name) != 0)
 302                         continue;
 303                 if (!mddev_busy(mp->devnum)) {
 304                         mp->bad = 1;
 305                         continue;
 306                 }
 307                 return mp;
 308         }
 309         return NULL;
 310 }
 311
 312 /* sets the proper subarray and container_dev according to the metadata
 313  * version super_by_fd does this automatically, this routine is meant as
 314  * a supplement for guess_super()
 315  */
 316 static void set_member_info(struct supertype *st, struct mdstat_ent *ent)
 317 {
 318
 319         st->subarray[0] = '\0';
 320
 321         if (ent->metadata_version == NULL ||
 322             strncmp(ent->metadata_version, "external:", 9) != 0)
 323                 return;
 324
 325         if (is_subarray(&ent->metadata_version[9])) {
 326                 char version[strlen(ent->metadata_version)+1];
 327                 char *subarray;
 328                 char *name = &version[10];
 329
 330                 strcpy(version, ent->metadata_version);
 331                 subarray = strrchr(version, '/');
 332                 name = &version[10];
 333
 334                 if (!subarray)
 335                         return;
 336                 *subarray++ = '\0';
 337
 338                 st->container_dev = devname2devnum(name);
 339                 strncpy(st->subarray, subarray, sizeof(st->subarray));
 340         }
 341 }
 342
 343 void RebuildMap(void)
 344 {
 345         struct mdstat_ent *mdstat = mdstat_read(0, 0);
 346         struct mdstat_ent *md;
 347         struct map_ent *map = NULL;
 348         int mdp = get_mdp_major();
 349         int require_homehost;
 350         char sys_hostname[256];
 351         char *homehost = conf_get_homehost(&require_homehost);
 352
 353         if (homehost == NULL || strcmp(homehost, "<system>")==0) {
 354                 if (gethostname(sys_hostname, sizeof(sys_hostname)) == 0) {
 355                         sys_hostname[sizeof(sys_hostname)-1] = 0;
 356                         homehost = sys_hostname;
 357                 }
 358         }
 359
 360         for (md = mdstat ; md ; md = md->next) {
 361                 struct mdinfo *sra = sysfs_read(-1, md->devnum, GET_DEVS|SKIP_GONE_DEVS);
 362                 struct mdinfo *sd;
 363
 364                 if (!sra)
 365                         continue;
 366
 367                 for (sd = sra->devs ; sd ; sd = sd->next) {
 368                         char namebuf[100];
 369                         char dn[30];
 370                         int dfd;
 371                         int ok;
 372                         struct supertype *st;
 373                         char *path;
 374                         struct mdinfo info;
 375
 376                         sprintf(dn, "%d:%d", sd->disk.major, sd->disk.minor);
 377                         dfd = dev_open(dn, O_RDONLY);
 378                         if (dfd < 0)
 379                                 continue;
 380                         st = guess_super(dfd);
 381                         if ( st == NULL)
 382                                 ok = -1;
 383                         else {
 384                                 set_member_info(st, md);
 385                                 ok = st->ss->load_super(st, dfd, NULL);
 386                         }
 387                         close(dfd);
 388                         if (ok != 0)
 389                                 continue;
 390                         st->ss->getinfo_super(st, &info);
 391                         if (md->devnum >= 0)
 392                                 path = map_dev(MD_MAJOR, md->devnum, 0);
 393                         else
 394                                 path = map_dev(mdp, (-1-md->devnum)<< 6, 0);
 395                         if (path == NULL ||
 396                             strncmp(path, "/dev/md/", 8) != 0) {
 397                                 /* We would really like a name that provides
 398                                  * an MD_DEVNAME for udev.
 399                                  * The name needs to be unique both in /dev/md/
 400                                  * and in this mapfile.
 401                                  * It needs to match watch -I or -As would come
 402                                  * up with.
 403                                  * That means:
 404                                  *   Check if array is in mdadm.conf
 405                                  *        - if so use that.
 406                                  *   determine trustworthy from homehost etc
 407                                  *   find a unique name based on metadata name.
 408                                  *
 409                                  */
 410                                 struct mddev_ident_s *match = conf_match(&info, st);
 411                                 struct stat stb;
 412                                 if (match && match->devname && match->devname[0] == '/') {
 413                                         path = match->devname;
 414                                         if (path[0] != '/') {
 415                                                 strcpy(namebuf, "/dev/md/");
 416                                                 strcat(namebuf, path);
 417                                                 path = namebuf;
 418                                         }
 419                                 } else {
 420                                         int unum = 0;
 421                                         char *sep = "_";
 422                                         const char *name;
 423                                         int conflict = 1;
 424                                         if ((homehost == NULL ||
 425                                              st->ss->match_home(st, homehost) != 1) &&
 426                                             st->ss->match_home(st, "any") != 1 &&
 427                                             (require_homehost
 428                                              || ! conf_name_is_free(info.name)))
 429                                                 /* require a numeric suffix */
 430                                                 unum = 0;
 431                                         else
 432                                                 /* allow name to be used as-is if no conflict */
 433                                                 unum = -1;
 434                                         name = info.name;
 435                                         if (!*name) {
 436                                                 name = st->ss->name;
 437                                                 if (!isdigit(name[strlen(name)-1]) &&
 438                                                     unum == -1) {
 439                                                         unum = 0;
 440                                                         sep = "";
 441                                                 }
 442                                         }
 443                                         if (strchr(name, ':'))
 444                                                 /* probably a uniquifying
 445                                                  * hostname prefix.  Allow
 446                                                  * without a suffix
 447                                                  */
 448                                                 unum = -1;
 449
 450                                         while (conflict) {
 451                                                 if (unum >= 0)
 452                                                         sprintf(namebuf, "/dev/md/%s%s%d",
 453                                                                 name, sep, unum);
 454                                                 else
 455                                                         sprintf(namebuf, "/dev/md/%s",
 456                                                                 name);
 457                                                 unum++;
 458                                                 if (lstat(namebuf, &stb) != 0 &&
 459                                                     (map == NULL ||
 460                                                      !map_by_name(&map, namebuf+8)))
 461                                                         conflict = 0;
 462                                         }
 463                                         path = namebuf;
 464                                 }
 465                         }
 466                         map_add(&map, md->devnum,
 467                                 info.text_version,
 468                                 info.uuid, path);
 469                         st->ss->free_super(st);
 470                         break;
 471                 }
 472                 sysfs_free(sra);
 473         }
 474         /* Only trigger a change if we wrote a new map file */
 475         if (map_write(map))
 476                 for (md = mdstat ; md ; md = md->next) {
 477                         struct mdinfo *sra = sysfs_read(-1, md->devnum,
 478                                                         GET_VERSION);
 479                         sysfs_uevent(sra, "change");
 480                         sysfs_free(sra);
 481                 }
 482         map_free(map);
 483         free_mdstat(mdstat);
 484 }