contrib/lvm2/dist/lib/label/label.c

   1 /*      $NetBSD: label.c,v 1.1.1.2 2009/12/02 00:26:32 haad Exp $       */
   2
   3 /*
   4  * Copyright (C) 2002-2004 Sistina Software, Inc. All rights reserved.
   5  * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
   6  *
   7  * This file is part of LVM2.
   8  *
   9  * This copyrighted material is made available to anyone wishing to use,
  10  * modify, copy, or redistribute it subject to the terms and conditions
  11  * of the GNU Lesser General Public License v.2.1.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public License
  14  * along with this program; if not, write to the Free Software Foundation,
  15  * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  16  */
  17
  18 #include "lib.h"
  19 #include "label.h"
  20 #include "crc.h"
  21 #include "xlate.h"
  22 #include "lvmcache.h"
  23 #include "metadata.h"
  24
  25 #include <sys/stat.h>
  26 #include <fcntl.h>
  27 #include <unistd.h>
  28
  29 /* FIXME Allow for larger labels?  Restricted to single sector currently */
  30
  31 /*
  32  * Internal labeller struct.
  33  */
  34 struct labeller_i {
  35         struct dm_list list;
  36
  37         struct labeller *l;
  38         char name[0];
  39 };
  40
  41 static struct dm_list _labellers;
  42
  43 static struct labeller_i *_alloc_li(const char *name, struct labeller *l)
  44 {
  45         struct labeller_i *li;
  46         size_t len;
  47
  48         len = sizeof(*li) + strlen(name) + 1;
  49
  50         if (!(li = dm_malloc(len))) {
  51                 log_error("Couldn't allocate memory for labeller list object.");
  52                 return NULL;
  53         }
  54
  55         li->l = l;
  56         strcpy(li->name, name);
  57
  58         return li;
  59 }
  60
  61 static void _free_li(struct labeller_i *li)
  62 {
  63         dm_free(li);
  64 }
  65
  66 int label_init(void)
  67 {
  68         dm_list_init(&_labellers);
  69         return 1;
  70 }
  71
  72 void label_exit(void)
  73 {
  74         struct dm_list *c, *n;
  75         struct labeller_i *li;
  76
  77         for (c = _labellers.n; c && c != &_labellers; c = n) {
  78                 n = c->n;
  79                 li = dm_list_item(c, struct labeller_i);
  80                 li->l->ops->destroy(li->l);
  81                 _free_li(li);
  82         }
  83
  84         dm_list_init(&_labellers);
  85 }
  86
  87 int label_register_handler(const char *name, struct labeller *handler)
  88 {
  89         struct labeller_i *li;
  90
  91         if (!(li = _alloc_li(name, handler)))
  92                 return_0;
  93
  94         dm_list_add(&_labellers, &li->list);
  95         return 1;
  96 }
  97
  98 struct labeller *label_get_handler(const char *name)
  99 {
 100         struct labeller_i *li;
 101
 102         dm_list_iterate_items(li, &_labellers)
 103                 if (!strcmp(li->name, name))
 104                         return li->l;
 105
 106         return NULL;
 107 }
 108
 109 static struct labeller *_find_labeller(struct device *dev, char *buf,
 110                                        uint64_t *label_sector,
 111                                        uint64_t scan_sector)
 112 {
 113         struct labeller_i *li;
 114         struct labeller *r = NULL;
 115         struct label_header *lh;
 116         struct lvmcache_info *info;
 117         uint64_t sector;
 118         int found = 0;
 119         char readbuf[LABEL_SCAN_SIZE] __attribute((aligned(8)));
 120
 121         if (!dev_read(dev, scan_sector << SECTOR_SHIFT,
 122                       LABEL_SCAN_SIZE, readbuf)) {
 123                 log_debug("%s: Failed to read label area", dev_name(dev));
 124                 goto out;
 125         }
 126
 127         /* Scan a few sectors for a valid label */
 128         for (sector = 0; sector < LABEL_SCAN_SECTORS;
 129              sector += LABEL_SIZE >> SECTOR_SHIFT) {
 130                 lh = (struct label_header *) (readbuf +
 131                                               (sector << SECTOR_SHIFT));
 132
 133                 if (!strncmp((char *)lh->id, LABEL_ID, sizeof(lh->id))) {
 134                         if (found) {
 135                                 log_error("Ignoring additional label on %s at "
 136                                           "sector %" PRIu64, dev_name(dev),
 137                                           sector + scan_sector);
 138                         }
 139                         if (xlate64(lh->sector_xl) != sector + scan_sector) {
 140                                 log_info("%s: Label for sector %" PRIu64
 141                                          " found at sector %" PRIu64
 142                                          " - ignoring", dev_name(dev),
 143                                          (uint64_t)xlate64(lh->sector_xl),
 144                                          sector + scan_sector);
 145                                 continue;
 146                         }
 147                         if (calc_crc(INITIAL_CRC, &lh->offset_xl, LABEL_SIZE -
 148                                      ((uintptr_t) &lh->offset_xl - (uintptr_t) lh)) !=
 149                             xlate32(lh->crc_xl)) {
 150                                 log_info("Label checksum incorrect on %s - "
 151                                          "ignoring", dev_name(dev));
 152                                 continue;
 153                         }
 154                         if (found)
 155                                 continue;
 156                 }
 157
 158                 dm_list_iterate_items(li, &_labellers) {
 159                         if (li->l->ops->can_handle(li->l, (char *) lh,
 160                                                    sector + scan_sector)) {
 161                                 log_very_verbose("%s: %s label detected",
 162                                                  dev_name(dev), li->name);
 163                                 if (found) {
 164                                         log_error("Ignoring additional label "
 165                                                   "on %s at sector %" PRIu64,
 166                                                   dev_name(dev),
 167                                                   sector + scan_sector);
 168                                         continue;
 169                                 }
 170                                 r = li->l;
 171                                 memcpy(buf, lh, LABEL_SIZE);
 172                                 if (label_sector)
 173                                         *label_sector = sector + scan_sector;
 174                                 found = 1;
 175                                 break;
 176                         }
 177                 }
 178         }
 179
 180       out:
 181         if (!found) {
 182                 if ((info = info_from_pvid(dev->pvid, 0)))
 183                         lvmcache_update_vgname_and_id(info, info->fmt->orphan_vg_name,
 184                                                       info->fmt->orphan_vg_name,
 185                                                       0, NULL);
 186                 log_very_verbose("%s: No label detected", dev_name(dev));
 187         }
 188
 189         return r;
 190 }
 191
 192 /* FIXME Also wipe associated metadata area headers? */
 193 int label_remove(struct device *dev)
 194 {
 195         char buf[LABEL_SIZE] __attribute((aligned(8)));
 196         char readbuf[LABEL_SCAN_SIZE] __attribute((aligned(8)));
 197         int r = 1;
 198         uint64_t sector;
 199         int wipe;
 200         struct labeller_i *li;
 201         struct label_header *lh;
 202
 203         memset(buf, 0, LABEL_SIZE);
 204
 205         log_very_verbose("Scanning for labels to wipe from %s", dev_name(dev));
 206
 207         if (!dev_open(dev))
 208                 return_0;
 209
 210         /*
 211          * We flush the device just in case someone is stupid
 212          * enough to be trying to import an open pv into lvm.
 213          */
 214         dev_flush(dev);
 215
 216         if (!dev_read(dev, UINT64_C(0), LABEL_SCAN_SIZE, readbuf)) {
 217                 log_debug("%s: Failed to read label area", dev_name(dev));
 218                 goto out;
 219         }
 220
 221         /* Scan first few sectors for anything looking like a label */
 222         for (sector = 0; sector < LABEL_SCAN_SECTORS;
 223              sector += LABEL_SIZE >> SECTOR_SHIFT) {
 224                 lh = (struct label_header *) (readbuf +
 225                                               (sector << SECTOR_SHIFT));
 226
 227                 wipe = 0;
 228
 229                 if (!strncmp((char *)lh->id, LABEL_ID, sizeof(lh->id))) {
 230                         if (xlate64(lh->sector_xl) == sector)
 231                                 wipe = 1;
 232                 } else {
 233                         dm_list_iterate_items(li, &_labellers) {
 234                                 if (li->l->ops->can_handle(li->l, (char *) lh,
 235                                                            sector)) {
 236                                         wipe = 1;
 237                                         break;
 238                                 }
 239                         }
 240                 }
 241
 242                 if (wipe) {
 243                         log_info("%s: Wiping label at sector %" PRIu64,
 244                                  dev_name(dev), sector);
 245                         if (!dev_write(dev, sector << SECTOR_SHIFT, LABEL_SIZE,
 246                                        buf)) {
 247                                 log_error("Failed to remove label from %s at "
 248                                           "sector %" PRIu64, dev_name(dev),
 249                                           sector);
 250                                 r = 0;
 251                         }
 252                 }
 253         }
 254
 255       out:
 256         if (!dev_close(dev))
 257                 stack;
 258
 259         return r;
 260 }
 261
 262 int label_read(struct device *dev, struct label **result,
 263                 uint64_t scan_sector)
 264 {
 265         char buf[LABEL_SIZE] __attribute((aligned(8)));
 266         struct labeller *l;
 267         uint64_t sector;
 268         struct lvmcache_info *info;
 269         int r = 0;
 270
 271         if ((info = info_from_pvid(dev->pvid, 1))) {
 272                 log_debug("Using cached label for %s", dev_name(dev));
 273                 *result = info->label;
 274                 return 1;
 275         }
 276
 277         if (!dev_open(dev)) {
 278                 stack;
 279
 280                 if ((info = info_from_pvid(dev->pvid, 0)))
 281                         lvmcache_update_vgname_and_id(info, info->fmt->orphan_vg_name,
 282                                                       info->fmt->orphan_vg_name,
 283                                                       0, NULL);
 284
 285                 return r;
 286         }
 287
 288         if (!(l = _find_labeller(dev, buf, &sector, scan_sector)))
 289                 goto out;
 290
 291         if ((r = (l->ops->read)(l, dev, buf, result)) && result && *result)
 292                 (*result)->sector = sector;
 293
 294       out:
 295         if (!dev_close(dev))
 296                 stack;
 297
 298         return r;
 299 }
 300
 301 /* Caller may need to use label_get_handler to create label struct! */
 302 int label_write(struct device *dev, struct label *label)
 303 {
 304         char buf[LABEL_SIZE] __attribute((aligned(8)));
 305         struct label_header *lh = (struct label_header *) buf;
 306         int r = 1;
 307
 308         if (!label->labeller->ops->write) {
 309                 log_error("Label handler does not support label writes");
 310                 return 0;
 311         }
 312
 313         if ((LABEL_SIZE + (label->sector << SECTOR_SHIFT)) > LABEL_SCAN_SIZE) {
 314                 log_error("Label sector %" PRIu64 " beyond range (%ld)",
 315                           label->sector, LABEL_SCAN_SECTORS);
 316                 return 0;
 317         }
 318
 319         memset(buf, 0, LABEL_SIZE);
 320
 321         strncpy((char *)lh->id, LABEL_ID, sizeof(lh->id));
 322         lh->sector_xl = xlate64(label->sector);
 323         lh->offset_xl = xlate32(sizeof(*lh));
 324
 325         if (!(label->labeller->ops->write)(label, buf))
 326                 return_0;
 327
 328         lh->crc_xl = xlate32(calc_crc(INITIAL_CRC, &lh->offset_xl, LABEL_SIZE -
 329                                       ((uintptr_t) &lh->offset_xl - (uintptr_t) lh)));
 330
 331         if (!dev_open(dev))
 332                 return_0;
 333
 334         log_info("%s: Writing label to sector %" PRIu64 " with stored offset %"
 335                  PRIu32 ".", dev_name(dev), label->sector,
 336                  xlate32(lh->offset_xl));
 337         if (!dev_write(dev, label->sector << SECTOR_SHIFT, LABEL_SIZE, buf)) {
 338                 log_debug("Failed to write label to %s", dev_name(dev));
 339                 r = 0;
 340         }
 341
 342         if (!dev_close(dev))
 343                 stack;
 344
 345         return r;
 346 }
 347
 348 /* Unused */
 349 int label_verify(struct device *dev)
 350 {
 351         struct labeller *l;
 352         char buf[LABEL_SIZE] __attribute((aligned(8)));
 353         uint64_t sector;
 354         struct lvmcache_info *info;
 355         int r = 0;
 356
 357         if (!dev_open(dev)) {
 358                 if ((info = info_from_pvid(dev->pvid, 0)))
 359                         lvmcache_update_vgname_and_id(info, info->fmt->orphan_vg_name,
 360                                                       info->fmt->orphan_vg_name,
 361                                                       0, NULL);
 362
 363                 return_0;
 364         }
 365
 366         if (!(l = _find_labeller(dev, buf, &sector, UINT64_C(0))))
 367                 goto out;
 368
 369         r = l->ops->verify ? l->ops->verify(l, buf, sector) : 1;
 370
 371       out:
 372         if (!dev_close(dev))
 373                 stack;
 374
 375         return r;
 376 }
 377
 378 void label_destroy(struct label *label)
 379 {
 380         label->labeller->ops->destroy_label(label->labeller, label);
 381         dm_free(label);
 382 }
 383
 384 struct label *label_create(struct labeller *labeller)
 385 {
 386         struct label *label;
 387
 388         if (!(label = dm_malloc(sizeof(*label)))) {
 389                 log_error("label allocaction failed");
 390                 return NULL;
 391         }
 392         memset(label, 0, sizeof(*label));
 393
 394         label->labeller = labeller;
 395
 396         labeller->ops->initialise_label(labeller, label);
 397
 398         return label;
 399 }