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  * more.  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  /dev/.mdadm.map
  46  * the last, because udev requires a writable /dev very early.
  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
  52 #define mapnames(base) { #base, #base ".new", #base ".lock"}
  53 char *mapname[3][3] = {
  54         mapnames(/var/run/mdadm/map),
  55         mapnames(/var/run/mdadm.map),
  56         mapnames(/dev/.mdadm.map)
  57 };
  58
  59 int mapmode[3] = { O_RDONLY, O_RDWR|O_CREAT, O_RDWR|O_CREAT | O_TRUNC };
  60 char *mapsmode[3] = { "r", "w", "w"};
  61
  62 FILE *open_map(int modenum, int *choice)
  63 {
  64         int i;
  65         for (i = 0 ; i < 3 ; i++) {
  66                 int fd = open(mapname[i][modenum], mapmode[modenum], 0600);
  67                 if (fd >= 0) {
  68                         *choice = i;
  69                         return fdopen(fd, mapsmode[modenum]);
  70                 }
  71         }
  72         return NULL;
  73 }
  74
  75 int map_write(struct map_ent *mel)
  76 {
  77         FILE *f;
  78         int err;
  79         int which;
  80
  81         f = open_map(1, &which);
  82
  83         if (!f)
  84                 return 0;
  85         for (; mel; mel = mel->next) {
  86                 if (mel->bad)
  87                         continue;
  88                 if (mel->devnum < 0)
  89                         fprintf(f, "mdp%d ", -1-mel->devnum);
  90                 else
  91                         fprintf(f, "md%d ", mel->devnum);
  92                 fprintf(f, "%s ", mel->metadata);
  93                 fprintf(f, "%08x:%08x:%08x:%08x ", mel->uuid[0],
  94                         mel->uuid[1], mel->uuid[2], mel->uuid[3]);
  95                 fprintf(f, "%s\n", mel->path?:"");
  96         }
  97         fflush(f);
  98         err = ferror(f);
  99         fclose(f);
 100         if (err) {
 101                 unlink(mapname[which][1]);
 102                 return 0;
 103         }
 104         return rename(mapname[which][1],
 105                       mapname[which][0]) == 0;
 106 }
 107
 108
 109 static FILE *lf = NULL;
 110 static int lwhich = 0;
 111 int map_lock(struct map_ent **melp)
 112 {
 113         if (lf == NULL) {
 114                 lf = open_map(2, &lwhich);
 115                 if (lf == NULL)
 116                         return -1;
 117                 if (lockf(fileno(lf), F_LOCK, 0) != 0) {
 118                         fclose(lf);
 119                         lf = NULL;
 120                         return -1;
 121                 }
 122         }
 123         if (*melp)
 124                 map_free(*melp);
 125         map_read(melp);
 126         return 0;
 127 }
 128
 129 void map_unlock(struct map_ent **melp)
 130 {
 131         if (lf)
 132                 fclose(lf);
 133         unlink(mapname[lwhich][2]);
 134         lf = NULL;
 135 }
 136
 137 void map_add(struct map_ent **melp,
 138             int devnum, char *metadata, int uuid[4], char *path)
 139 {
 140         struct map_ent *me = malloc(sizeof(*me));
 141
 142         me->devnum = devnum;
 143         strcpy(me->metadata, metadata);
 144         memcpy(me->uuid, uuid, 16);
 145         me->path = path ? strdup(path) : NULL;
 146         me->next = *melp;
 147         me->bad = 0;
 148         *melp = me;
 149 }
 150
 151 void map_read(struct map_ent **melp)
 152 {
 153         FILE *f;
 154         char buf[8192];
 155         char path[200];
 156         int devnum, uuid[4];
 157         char metadata[30];
 158         char nam[4];
 159         int which;
 160
 161         *melp = NULL;
 162
 163         f = open_map(0, &which);
 164         if (!f) {
 165                 RebuildMap();
 166                 f = open_map(0, &which);
 167         }
 168         if (!f)
 169                 return;
 170
 171         while (fgets(buf, sizeof(buf), f)) {
 172                 path[0] = 0;
 173                 if (sscanf(buf, " %3[mdp]%d %s %x:%x:%x:%x %200s",
 174                            nam, &devnum, metadata, uuid, uuid+1,
 175                            uuid+2, uuid+3, path) >= 7) {
 176                         if (strncmp(nam, "md", 2) != 0)
 177                                 continue;
 178                         if (nam[2] == 'p')
 179                                 devnum = -1 - devnum;
 180                         map_add(melp, devnum, metadata, uuid, path);
 181                 }
 182         }
 183         fclose(f);
 184 }
 185
 186 void map_free(struct map_ent *map)
 187 {
 188         while (map) {
 189                 struct map_ent *mp = map;
 190                 map = mp->next;
 191                 free(mp->path);
 192                 free(mp);
 193         }
 194 }
 195
 196 int map_update(struct map_ent **mpp, int devnum, char *metadata,
 197                int *uuid, char *path)
 198 {
 199         struct map_ent *map, *mp;
 200         int rv;
 201
 202         if (mpp && *mpp)
 203                 map = *mpp;
 204         else
 205                 map_read(&map);
 206
 207         for (mp = map ; mp ; mp=mp->next)
 208                 if (mp->devnum == devnum) {
 209                         strcpy(mp->metadata, metadata);
 210                         memcpy(mp->uuid, uuid, 16);
 211                         free(mp->path);
 212                         mp->path = path ? strdup(path) : NULL;
 213                         break;
 214                 }
 215         if (!mp)
 216                 map_add(&map, devnum, metadata, uuid, path);
 217         if (mpp)
 218                 *mpp = NULL;
 219         rv = map_write(map);
 220         map_free(map);
 221         return rv;
 222 }
 223
 224 void map_delete(struct map_ent **mapp, int devnum)
 225 {
 226         struct map_ent *mp;
 227
 228         if (*mapp == NULL)
 229                 map_read(mapp);
 230
 231         for (mp = *mapp; mp; mp = *mapp) {
 232                 if (mp->devnum == devnum) {
 233                         *mapp = mp->next;
 234                         free(mp->path);
 235                         free(mp);
 236                 } else
 237                         mapp = & mp->next;
 238         }
 239 }
 240
 241 struct map_ent *map_by_uuid(struct map_ent **map, int uuid[4])
 242 {
 243         struct map_ent *mp;
 244         if (!*map)
 245                 map_read(map);
 246
 247         for (mp = *map ; mp ; mp = mp->next) {
 248                 if (memcmp(uuid, mp->uuid, 16) != 0)
 249                         continue;
 250                 if (!mddev_busy(mp->devnum)) {
 251                         mp->bad = 1;
 252                         continue;
 253                 }
 254                 return mp;
 255         }
 256         return NULL;
 257 }
 258
 259 struct map_ent *map_by_devnum(struct map_ent **map, int devnum)
 260 {
 261         struct map_ent *mp;
 262         if (!*map)
 263                 map_read(map);
 264
 265         for (mp = *map ; mp ; mp = mp->next) {
 266                 if (mp->devnum != devnum)
 267                         continue;
 268                 if (!mddev_busy(mp->devnum)) {
 269                         mp->bad = 1;
 270                         continue;
 271                 }
 272                 return mp;
 273         }
 274         return NULL;
 275 }
 276
 277 struct map_ent *map_by_name(struct map_ent **map, char *name)
 278 {
 279         struct map_ent *mp;
 280         if (!*map)
 281                 map_read(map);
 282
 283         for (mp = *map ; mp ; mp = mp->next) {
 284                 if (!mp->path)
 285                         continue;
 286                 if (strncmp(mp->path, "/dev/md/", 8) != 0)
 287                         continue;
 288                 if (strcmp(mp->path+8, name) != 0)
 289                         continue;
 290                 if (!mddev_busy(mp->devnum)) {
 291                         mp->bad = 1;
 292                         continue;
 293                 }
 294                 return mp;
 295         }
 296         return NULL;
 297 }
 298
 299 void RebuildMap(void)
 300 {
 301         struct mdstat_ent *mdstat = mdstat_read(0, 0);
 302         struct mdstat_ent *md;
 303         struct map_ent *map = NULL;
 304         int mdp = get_mdp_major();
 305
 306         for (md = mdstat ; md ; md = md->next) {
 307                 struct mdinfo *sra = sysfs_read(-1, md->devnum, GET_DEVS|SKIP_GONE_DEVS);
 308                 struct mdinfo *sd;
 309
 310                 if (!sra)
 311                         continue;
 312
 313                 for (sd = sra->devs ; sd ; sd = sd->next) {
 314                         char dn[30];
 315                         int dfd;
 316                         int ok;
 317                         struct supertype *st;
 318                         char *path;
 319                         struct mdinfo info;
 320
 321                         sprintf(dn, "%d:%d", sd->disk.major, sd->disk.minor);
 322                         dfd = dev_open(dn, O_RDONLY);
 323                         if (dfd < 0)
 324                                 continue;
 325                         st = guess_super(dfd);
 326                         if ( st == NULL)
 327                                 ok = -1;
 328                         else
 329                                 ok = st->ss->load_super(st, dfd, NULL);
 330                         close(dfd);
 331                         if (ok != 0)
 332                                 continue;
 333                         st->ss->getinfo_super(st, &info);
 334                         if (md->devnum >= 0)
 335                                 path = map_dev(MD_MAJOR, md->devnum, 0);
 336                         else
 337                                 path = map_dev(mdp, (-1-md->devnum)<< 6, 0);
 338                         map_add(&map, md->devnum,
 339                                 info.text_version,
 340                                 info.uuid, path);
 341                         st->ss->free_super(st);
 342                         break;
 343                 }
 344                 sysfs_free(sra);
 345         }
 346         map_write(map);
 347         map_free(map);
 348         for (md = mdstat ; md ; md = md->next) {
 349                 struct mdinfo *sra = sysfs_read(-1, md->devnum, GET_VERSION);
 350                 sysfs_uevent(sra, "change");
 351                 sysfs_free(sra);
 352         }
 353         free_mdstat(mdstat);
 354 }