release/src-rt-6.x.4708/linux/linux-2.6.36/fs/partitions/check.c

   1 /*
   2  *  fs/partitions/check.c
   3  *
   4  *  Code extracted from drivers/block/genhd.c
   5  *  Copyright (C) 1991-1998  Linus Torvalds
   6  *  Re-organised Feb 1998 Russell King
   7  *
   8  *  We now have independent partition support from the
   9  *  block drivers, which allows all the partition code to
  10  *  be grouped in one location, and it to be mostly self
  11  *  contained.
  12  *
  13  *  Added needed MAJORS for new pairs, {hdi,hdj}, {hdk,hdl}
  14  */
  15
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/fs.h>
  19 #include <linux/slab.h>
  20 #include <linux/kmod.h>
  21 #include <linux/ctype.h>
  22 #include <linux/genhd.h>
  23 #include <linux/blktrace_api.h>
  24
  25 #include "check.h"
  26
  27 #include "acorn.h"
  28 #include "amiga.h"
  29 #include "atari.h"
  30 #include "ldm.h"
  31 #include "mac.h"
  32 #include "msdos.h"
  33 #include "osf.h"
  34 #include "sgi.h"
  35 #include "sun.h"
  36 #include "ibm.h"
  37 #include "ultrix.h"
  38 #include "efi.h"
  39 #include "karma.h"
  40 #include "sysv68.h"
  41
  42 #ifdef CONFIG_BLK_DEV_MD
  43 extern void md_autodetect_dev(dev_t dev);
  44 #endif
  45
  46 int warn_no_part = 1; /*This is ugly: should make genhd removable media aware*/
  47
  48 static int (*check_part[])(struct parsed_partitions *) = {
  49         /*
  50          * Probe partition formats with tables at disk address 0
  51          * that also have an ADFS boot block at 0xdc0.
  52          */
  53 #ifdef CONFIG_ACORN_PARTITION_ICS
  54         adfspart_check_ICS,
  55 #endif
  56 #ifdef CONFIG_ACORN_PARTITION_POWERTEC
  57         adfspart_check_POWERTEC,
  58 #endif
  59 #ifdef CONFIG_ACORN_PARTITION_EESOX
  60         adfspart_check_EESOX,
  61 #endif
  62
  63         /*
  64          * Now move on to formats that only have partition info at
  65          * disk address 0xdc0.  Since these may also have stale
  66          * PC/BIOS partition tables, they need to come before
  67          * the msdos entry.
  68          */
  69 #ifdef CONFIG_ACORN_PARTITION_CUMANA
  70         adfspart_check_CUMANA,
  71 #endif
  72 #ifdef CONFIG_ACORN_PARTITION_ADFS
  73         adfspart_check_ADFS,
  74 #endif
  75
  76 #ifdef CONFIG_EFI_PARTITION
  77         efi_partition,          /* this must come before msdos */
  78 #endif
  79 #ifdef CONFIG_SGI_PARTITION
  80         sgi_partition,
  81 #endif
  82 #ifdef CONFIG_LDM_PARTITION
  83         ldm_partition,          /* this must come before msdos */
  84 #endif
  85 #ifdef CONFIG_MSDOS_PARTITION
  86         msdos_partition,
  87 #endif
  88 #ifdef CONFIG_OSF_PARTITION
  89         osf_partition,
  90 #endif
  91 #ifdef CONFIG_SUN_PARTITION
  92         sun_partition,
  93 #endif
  94 #ifdef CONFIG_AMIGA_PARTITION
  95         amiga_partition,
  96 #endif
  97 #ifdef CONFIG_ATARI_PARTITION
  98         atari_partition,
  99 #endif
 100 #ifdef CONFIG_MAC_PARTITION
 101         mac_partition,
 102 #endif
 103 #ifdef CONFIG_ULTRIX_PARTITION
 104         ultrix_partition,
 105 #endif
 106 #ifdef CONFIG_IBM_PARTITION
 107         ibm_partition,
 108 #endif
 109 #ifdef CONFIG_KARMA_PARTITION
 110         karma_partition,
 111 #endif
 112 #ifdef CONFIG_SYSV68_PARTITION
 113         sysv68_partition,
 114 #endif
 115         NULL
 116 };
 117
 118 /*
 119  * disk_name() is used by partition check code and the genhd driver.
 120  * It formats the devicename of the indicated disk into
 121  * the supplied buffer (of size at least 32), and returns
 122  * a pointer to that same buffer (for convenience).
 123  */
 124
 125 char *disk_name(struct gendisk *hd, int partno, char *buf)
 126 {
 127         if (!partno)
 128                 snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
 129         else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
 130                 snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
 131         else
 132                 snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
 133
 134         return buf;
 135 }
 136
 137 const char *bdevname(struct block_device *bdev, char *buf)
 138 {
 139         return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
 140 }
 141
 142 EXPORT_SYMBOL(bdevname);
 143
 144 /*
 145  * There's very little reason to use this, you should really
 146  * have a struct block_device just about everywhere and use
 147  * bdevname() instead.
 148  */
 149 const char *__bdevname(dev_t dev, char *buffer)
 150 {
 151         scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
 152                                 MAJOR(dev), MINOR(dev));
 153         return buffer;
 154 }
 155
 156 EXPORT_SYMBOL(__bdevname);
 157
 158 static struct parsed_partitions *
 159 check_partition(struct gendisk *hd, struct block_device *bdev)
 160 {
 161         struct parsed_partitions *state;
 162         int i, res, err;
 163
 164         state = kzalloc(sizeof(struct parsed_partitions), GFP_KERNEL);
 165         if (!state)
 166                 return NULL;
 167         state->pp_buf = (char *)__get_free_page(GFP_KERNEL);
 168         if (!state->pp_buf) {
 169                 kfree(state);
 170                 return NULL;
 171         }
 172         state->pp_buf[0] = '\0';
 173
 174         state->bdev = bdev;
 175         disk_name(hd, 0, state->name);
 176         snprintf(state->pp_buf, PAGE_SIZE, " %s:", state->name);
 177         if (isdigit(state->name[strlen(state->name)-1]))
 178                 sprintf(state->name, "p");
 179
 180         state->limit = disk_max_parts(hd);
 181         i = res = err = 0;
 182         while (!res && check_part[i]) {
 183                 memset(&state->parts, 0, sizeof(state->parts));
 184                 res = check_part[i++](state);
 185                 if (res < 0) {
 186                         /* We have hit an I/O error which we don't report now.
 187                         * But record it, and let the others do their job.
 188                         */
 189                         err = res;
 190                         res = 0;
 191                 }
 192
 193         }
 194         if (res > 0) {
 195                 printk(KERN_INFO "%s", state->pp_buf);
 196
 197                 free_page((unsigned long)state->pp_buf);
 198                 return state;
 199         }
 200         if (state->access_beyond_eod)
 201                 err = -ENOSPC;
 202         if (err)
 203         /* The partition is unrecognized. So report I/O errors if there were any */
 204                 res = err;
 205         if (!res)
 206                 strlcat(state->pp_buf, " unknown partition table\n", PAGE_SIZE);
 207         else if (warn_no_part)
 208                 strlcat(state->pp_buf, " unable to read partition table\n", PAGE_SIZE);
 209
 210         printk(KERN_INFO "%s", state->pp_buf);
 211
 212         free_page((unsigned long)state->pp_buf);
 213         kfree(state);
 214         return ERR_PTR(res);
 215 }
 216
 217 static ssize_t part_partition_show(struct device *dev,
 218                                    struct device_attribute *attr, char *buf)
 219 {
 220         struct hd_struct *p = dev_to_part(dev);
 221
 222         return sprintf(buf, "%d\n", p->partno);
 223 }
 224
 225 static ssize_t part_start_show(struct device *dev,
 226                                struct device_attribute *attr, char *buf)
 227 {
 228         struct hd_struct *p = dev_to_part(dev);
 229
 230         return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
 231 }
 232
 233 ssize_t part_size_show(struct device *dev,
 234                        struct device_attribute *attr, char *buf)
 235 {
 236         struct hd_struct *p = dev_to_part(dev);
 237         return sprintf(buf, "%llu\n",(unsigned long long)p->nr_sects);
 238 }
 239
 240 ssize_t part_alignment_offset_show(struct device *dev,
 241                                    struct device_attribute *attr, char *buf)
 242 {
 243         struct hd_struct *p = dev_to_part(dev);
 244         return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
 245 }
 246
 247 ssize_t part_discard_alignment_show(struct device *dev,
 248                                    struct device_attribute *attr, char *buf)
 249 {
 250         struct hd_struct *p = dev_to_part(dev);
 251         return sprintf(buf, "%u\n", p->discard_alignment);
 252 }
 253
 254 ssize_t part_stat_show(struct device *dev,
 255                        struct device_attribute *attr, char *buf)
 256 {
 257         struct hd_struct *p = dev_to_part(dev);
 258         int cpu;
 259
 260         cpu = part_stat_lock();
 261         part_round_stats(cpu, p);
 262         part_stat_unlock();
 263         return sprintf(buf,
 264                 "%8lu %8lu %8llu %8u "
 265                 "%8lu %8lu %8llu %8u "
 266                 "%8u %8u %8u"
 267                 "\n",
 268                 part_stat_read(p, ios[READ]),
 269                 part_stat_read(p, merges[READ]),
 270                 (unsigned long long)part_stat_read(p, sectors[READ]),
 271                 jiffies_to_msecs(part_stat_read(p, ticks[READ])),
 272                 part_stat_read(p, ios[WRITE]),
 273                 part_stat_read(p, merges[WRITE]),
 274                 (unsigned long long)part_stat_read(p, sectors[WRITE]),
 275                 jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
 276                 part_in_flight(p),
 277                 jiffies_to_msecs(part_stat_read(p, io_ticks)),
 278                 jiffies_to_msecs(part_stat_read(p, time_in_queue)));
 279 }
 280
 281 ssize_t part_inflight_show(struct device *dev,
 282                         struct device_attribute *attr, char *buf)
 283 {
 284         struct hd_struct *p = dev_to_part(dev);
 285
 286         return sprintf(buf, "%8u %8u\n", p->in_flight[0], p->in_flight[1]);
 287 }
 288
 289 #ifdef CONFIG_FAIL_MAKE_REQUEST
 290 ssize_t part_fail_show(struct device *dev,
 291                        struct device_attribute *attr, char *buf)
 292 {
 293         struct hd_struct *p = dev_to_part(dev);
 294
 295         return sprintf(buf, "%d\n", p->make_it_fail);
 296 }
 297
 298 ssize_t part_fail_store(struct device *dev,
 299                         struct device_attribute *attr,
 300                         const char *buf, size_t count)
 301 {
 302         struct hd_struct *p = dev_to_part(dev);
 303         int i;
 304
 305         if (count > 0 && sscanf(buf, "%d", &i) > 0)
 306                 p->make_it_fail = (i == 0) ? 0 : 1;
 307
 308         return count;
 309 }
 310 #endif
 311
 312 static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
 313 static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
 314 static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
 315 static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
 316 static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
 317                    NULL);
 318 static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
 319 static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
 320 #ifdef CONFIG_FAIL_MAKE_REQUEST
 321 static struct device_attribute dev_attr_fail =
 322         __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
 323 #endif
 324
 325 static struct attribute *part_attrs[] = {
 326         &dev_attr_partition.attr,
 327         &dev_attr_start.attr,
 328         &dev_attr_size.attr,
 329         &dev_attr_alignment_offset.attr,
 330         &dev_attr_discard_alignment.attr,
 331         &dev_attr_stat.attr,
 332         &dev_attr_inflight.attr,
 333 #ifdef CONFIG_FAIL_MAKE_REQUEST
 334         &dev_attr_fail.attr,
 335 #endif
 336         NULL
 337 };
 338
 339 static struct attribute_group part_attr_group = {
 340         .attrs = part_attrs,
 341 };
 342
 343 static const struct attribute_group *part_attr_groups[] = {
 344         &part_attr_group,
 345 #ifdef CONFIG_BLK_DEV_IO_TRACE
 346         &blk_trace_attr_group,
 347 #endif
 348         NULL
 349 };
 350
 351 static void part_release(struct device *dev)
 352 {
 353         struct hd_struct *p = dev_to_part(dev);
 354         free_part_stats(p);
 355         kfree(p);
 356 }
 357
 358 struct device_type part_type = {
 359         .name           = "partition",
 360         .groups         = part_attr_groups,
 361         .release        = part_release,
 362 };
 363
 364 static void delete_partition_rcu_cb(struct rcu_head *head)
 365 {
 366         struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
 367
 368         part->start_sect = 0;
 369         part->nr_sects = 0;
 370         part_stat_set_all(part, 0);
 371         put_device(part_to_dev(part));
 372 }
 373
 374 void delete_partition(struct gendisk *disk, int partno)
 375 {
 376         struct disk_part_tbl *ptbl = disk->part_tbl;
 377         struct hd_struct *part;
 378
 379         if (partno >= ptbl->len)
 380                 return;
 381
 382         part = ptbl->part[partno];
 383         if (!part)
 384                 return;
 385
 386         blk_free_devt(part_devt(part));
 387         rcu_assign_pointer(ptbl->part[partno], NULL);
 388         rcu_assign_pointer(ptbl->last_lookup, NULL);
 389         kobject_put(part->holder_dir);
 390         device_del(part_to_dev(part));
 391
 392         call_rcu(&part->rcu_head, delete_partition_rcu_cb);
 393 }
 394
 395 static ssize_t whole_disk_show(struct device *dev,
 396                                struct device_attribute *attr, char *buf)
 397 {
 398         return 0;
 399 }
 400 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
 401                    whole_disk_show, NULL);
 402
 403 struct hd_struct *add_partition(struct gendisk *disk, int partno,
 404                                 sector_t start, sector_t len, int flags)
 405 {
 406         struct hd_struct *p;
 407         dev_t devt = MKDEV(0, 0);
 408         struct device *ddev = disk_to_dev(disk);
 409         struct device *pdev;
 410         struct disk_part_tbl *ptbl;
 411         const char *dname;
 412         int err;
 413
 414         err = disk_expand_part_tbl(disk, partno);
 415         if (err)
 416                 return ERR_PTR(err);
 417         ptbl = disk->part_tbl;
 418
 419         if (ptbl->part[partno])
 420                 return ERR_PTR(-EBUSY);
 421
 422         p = kzalloc(sizeof(*p), GFP_KERNEL);
 423         if (!p)
 424                 return ERR_PTR(-EBUSY);
 425
 426         if (!init_part_stats(p)) {
 427                 err = -ENOMEM;
 428                 goto out_free;
 429         }
 430         pdev = part_to_dev(p);
 431
 432         p->start_sect = start;
 433         p->alignment_offset =
 434                 queue_limit_alignment_offset(&disk->queue->limits, start);
 435         p->discard_alignment =
 436                 queue_limit_discard_alignment(&disk->queue->limits, start);
 437         p->nr_sects = len;
 438         p->partno = partno;
 439         p->policy = get_disk_ro(disk);
 440
 441         dname = dev_name(ddev);
 442         if (isdigit(dname[strlen(dname) - 1]))
 443                 dev_set_name(pdev, "%sp%d", dname, partno);
 444         else
 445                 dev_set_name(pdev, "%s%d", dname, partno);
 446
 447         device_initialize(pdev);
 448         pdev->class = &block_class;
 449         pdev->type = &part_type;
 450         pdev->parent = ddev;
 451
 452         err = blk_alloc_devt(p, &devt);
 453         if (err)
 454                 goto out_free_stats;
 455         pdev->devt = devt;
 456
 457         /* delay uevent until 'holders' subdir is created */
 458         dev_set_uevent_suppress(pdev, 1);
 459         err = device_add(pdev);
 460         if (err)
 461                 goto out_put;
 462
 463         err = -ENOMEM;
 464         p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
 465         if (!p->holder_dir)
 466                 goto out_del;
 467
 468         dev_set_uevent_suppress(pdev, 0);
 469         if (flags & ADDPART_FLAG_WHOLEDISK) {
 470                 err = device_create_file(pdev, &dev_attr_whole_disk);
 471                 if (err)
 472                         goto out_del;
 473         }
 474
 475         /* everything is up and running, commence */
 476         rcu_assign_pointer(ptbl->part[partno], p);
 477
 478         /* suppress uevent if the disk supresses it */
 479         if (!dev_get_uevent_suppress(ddev))
 480                 kobject_uevent(&pdev->kobj, KOBJ_ADD);
 481
 482         return p;
 483
 484 out_free_stats:
 485         free_part_stats(p);
 486 out_free:
 487         kfree(p);
 488         return ERR_PTR(err);
 489 out_del:
 490         kobject_put(p->holder_dir);
 491         device_del(pdev);
 492 out_put:
 493         put_device(pdev);
 494         blk_free_devt(devt);
 495         return ERR_PTR(err);
 496 }
 497
 498 /* Not exported, helper to add_disk(). */
 499 void register_disk(struct gendisk *disk)
 500 {
 501         struct device *ddev = disk_to_dev(disk);
 502         struct block_device *bdev;
 503         struct disk_part_iter piter;
 504         struct hd_struct *part;
 505         int err;
 506
 507         ddev->parent = disk->driverfs_dev;
 508
 509         dev_set_name(ddev, disk->disk_name);
 510
 511         /* delay uevents, until we scanned partition table */
 512         dev_set_uevent_suppress(ddev, 1);
 513
 514         if (device_add(ddev))
 515                 return;
 516 #ifndef CONFIG_SYSFS_DEPRECATED
 517         err = sysfs_create_link(block_depr, &ddev->kobj,
 518                                 kobject_name(&ddev->kobj));
 519         if (err) {
 520                 device_del(ddev);
 521                 return;
 522         }
 523 #endif
 524         disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
 525         disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
 526
 527         /* No minors to use for partitions */
 528         if (!disk_partitionable(disk))
 529                 goto exit;
 530
 531         /* No such device (e.g., media were just removed) */
 532         if (!get_capacity(disk))
 533                 goto exit;
 534
 535         bdev = bdget_disk(disk, 0);
 536         if (!bdev)
 537                 goto exit;
 538
 539         bdev->bd_invalidated = 1;
 540         err = blkdev_get(bdev, FMODE_READ);
 541         if (err < 0)
 542                 goto exit;
 543         blkdev_put(bdev, FMODE_READ);
 544
 545 exit:
 546         /* announce disk after possible partitions are created */
 547         dev_set_uevent_suppress(ddev, 0);
 548         kobject_uevent(&ddev->kobj, KOBJ_ADD);
 549
 550         /* announce possible partitions */
 551         disk_part_iter_init(&piter, disk, 0);
 552         while ((part = disk_part_iter_next(&piter)))
 553                 kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
 554         disk_part_iter_exit(&piter);
 555 }
 556
 557 static bool disk_unlock_native_capacity(struct gendisk *disk)
 558 {
 559         const struct block_device_operations *bdops = disk->fops;
 560
 561         if (bdops->unlock_native_capacity &&
 562             !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
 563                 printk(KERN_CONT "enabling native capacity\n");
 564                 bdops->unlock_native_capacity(disk);
 565                 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
 566                 return true;
 567         } else {
 568                 printk(KERN_CONT "truncated\n");
 569                 return false;
 570         }
 571 }
 572
 573 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
 574 {
 575         struct parsed_partitions *state = NULL;
 576         struct disk_part_iter piter;
 577         struct hd_struct *part;
 578         int p, highest, res;
 579 rescan:
 580         if (state && !IS_ERR(state)) {
 581                 kfree(state);
 582                 state = NULL;
 583         }
 584
 585         if (bdev->bd_part_count)
 586                 return -EBUSY;
 587         res = invalidate_partition(disk, 0);
 588         if (res)
 589                 return res;
 590
 591         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
 592         while ((part = disk_part_iter_next(&piter)))
 593                 delete_partition(disk, part->partno);
 594         disk_part_iter_exit(&piter);
 595
 596         if (disk->fops->revalidate_disk)
 597                 disk->fops->revalidate_disk(disk);
 598         check_disk_size_change(disk, bdev);
 599         bdev->bd_invalidated = 0;
 600         if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
 601                 return 0;
 602         if (IS_ERR(state)) {
 603                 /*
 604                  * I/O error reading the partition table.  If any
 605                  * partition code tried to read beyond EOD, retry
 606                  * after unlocking native capacity.
 607                  */
 608                 if (PTR_ERR(state) == -ENOSPC) {
 609                         printk(KERN_WARNING "%s: partition table beyond EOD, ",
 610                                disk->disk_name);
 611                         if (disk_unlock_native_capacity(disk))
 612                                 goto rescan;
 613                 }
 614                 return -EIO;
 615         }
 616         /*
 617          * If any partition code tried to read beyond EOD, try
 618          * unlocking native capacity even if partition table is
 619          * sucessfully read as we could be missing some partitions.
 620          */
 621         if (state->access_beyond_eod) {
 622                 printk(KERN_WARNING
 623                        "%s: partition table partially beyond EOD, ",
 624                        disk->disk_name);
 625                 if (disk_unlock_native_capacity(disk))
 626                         goto rescan;
 627         }
 628
 629         /* tell userspace that the media / partition table may have changed */
 630         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
 631
 632         /* Detect the highest partition number and preallocate
 633          * disk->part_tbl.  This is an optimization and not strictly
 634          * necessary.
 635          */
 636         for (p = 1, highest = 0; p < state->limit; p++)
 637                 if (state->parts[p].size)
 638                         highest = p;
 639
 640         disk_expand_part_tbl(disk, highest);
 641
 642         /* add partitions */
 643         for (p = 1; p < state->limit; p++) {
 644                 sector_t size, from;
 645
 646                 size = state->parts[p].size;
 647                 if (!size)
 648                         continue;
 649
 650                 from = state->parts[p].from;
 651                 if (from >= get_capacity(disk)) {
 652                         printk(KERN_WARNING
 653                                "%s: p%d start %llu is beyond EOD, ",
 654                                disk->disk_name, p, (unsigned long long) from);
 655                         if (disk_unlock_native_capacity(disk))
 656                                 goto rescan;
 657                         continue;
 658                 }
 659
 660                 if (from + size > get_capacity(disk)) {
 661                         printk(KERN_WARNING
 662                                "%s: p%d size %llu extends beyond EOD, ",
 663                                disk->disk_name, p, (unsigned long long) size);
 664
 665                         if (disk_unlock_native_capacity(disk)) {
 666                                 /* free state and restart */
 667                                 goto rescan;
 668                         } else {
 669                                 /*
 670                                  * we can not ignore partitions of broken tables
 671                                  * created by for example camera firmware, but
 672                                  * we limit them to the end of the disk to avoid
 673                                  * creating invalid block devices
 674                                  */
 675                                 size = get_capacity(disk) - from;
 676                         }
 677                 }
 678                 part = add_partition(disk, p, from, size,
 679                                      state->parts[p].flags);
 680                 if (IS_ERR(part)) {
 681                         printk(KERN_ERR " %s: p%d could not be added: %ld\n",
 682                                disk->disk_name, p, -PTR_ERR(part));
 683                         continue;
 684                 }
 685 #ifdef CONFIG_BLK_DEV_MD
 686                 if (state->parts[p].flags & ADDPART_FLAG_RAID)
 687                         md_autodetect_dev(part_to_dev(part)->devt);
 688 #endif
 689         }
 690         kfree(state);
 691         return 0;
 692 }
 693
 694 unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
 695 {
 696         struct address_space *mapping = bdev->bd_inode->i_mapping;
 697         struct page *page;
 698
 699         page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
 700                                  NULL);
 701         if (!IS_ERR(page)) {
 702                 if (PageError(page))
 703                         goto fail;
 704                 p->v = page;
 705                 return (unsigned char *)page_address(page) +  ((n & ((1 << (PAGE_CACHE_SHIFT - 9)) - 1)) << 9);
 706 fail:
 707                 page_cache_release(page);
 708         }
 709         p->v = NULL;
 710         return NULL;
 711 }
 712
 713 EXPORT_SYMBOL(read_dev_sector);
 714
 715 void del_gendisk(struct gendisk *disk)
 716 {
 717         struct disk_part_iter piter;
 718         struct hd_struct *part;
 719
 720         /* invalidate stuff */
 721         disk_part_iter_init(&piter, disk,
 722                              DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
 723         while ((part = disk_part_iter_next(&piter))) {
 724                 invalidate_partition(disk, part->partno);
 725                 delete_partition(disk, part->partno);
 726         }
 727         disk_part_iter_exit(&piter);
 728
 729         invalidate_partition(disk, 0);
 730         blk_free_devt(disk_to_dev(disk)->devt);
 731         set_capacity(disk, 0);
 732         disk->flags &= ~GENHD_FL_UP;
 733         unlink_gendisk(disk);
 734         part_stat_set_all(&disk->part0, 0);
 735         disk->part0.stamp = 0;
 736
 737         kobject_put(disk->part0.holder_dir);
 738         kobject_put(disk->slave_dir);
 739         disk->driverfs_dev = NULL;
 740 #ifndef CONFIG_SYSFS_DEPRECATED
 741         sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
 742 #endif
 743         device_del(disk_to_dev(disk));
 744 }