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
 168         state->bdev = bdev;
 169         disk_name(hd, 0, state->name);
 170         printk(KERN_INFO " %s:", state->name);
 171         if (isdigit(state->name[strlen(state->name)-1]))
 172                 sprintf(state->name, "p");
 173
 174         state->limit = disk_max_parts(hd);
 175         i = res = err = 0;
 176         while (!res && check_part[i]) {
 177                 memset(&state->parts, 0, sizeof(state->parts));
 178                 res = check_part[i++](state);
 179                 if (res < 0) {
 180                         /* We have hit an I/O error which we don't report now.
 181                         * But record it, and let the others do their job.
 182                         */
 183                         err = res;
 184                         res = 0;
 185                 }
 186
 187         }
 188         if (res > 0)
 189                 return state;
 190         if (state->access_beyond_eod)
 191                 err = -ENOSPC;
 192         if (err)
 193         /* The partition is unrecognized. So report I/O errors if there were any */
 194                 res = err;
 195         if (!res)
 196                 printk(" unknown partition table\n");
 197         else if (warn_no_part)
 198                 printk(" unable to read partition table\n");
 199         kfree(state);
 200         return ERR_PTR(res);
 201 }
 202
 203 static ssize_t part_partition_show(struct device *dev,
 204                                    struct device_attribute *attr, char *buf)
 205 {
 206         struct hd_struct *p = dev_to_part(dev);
 207
 208         return sprintf(buf, "%d\n", p->partno);
 209 }
 210
 211 static ssize_t part_start_show(struct device *dev,
 212                                struct device_attribute *attr, char *buf)
 213 {
 214         struct hd_struct *p = dev_to_part(dev);
 215
 216         return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
 217 }
 218
 219 ssize_t part_size_show(struct device *dev,
 220                        struct device_attribute *attr, char *buf)
 221 {
 222         struct hd_struct *p = dev_to_part(dev);
 223         return sprintf(buf, "%llu\n",(unsigned long long)p->nr_sects);
 224 }
 225
 226 ssize_t part_alignment_offset_show(struct device *dev,
 227                                    struct device_attribute *attr, char *buf)
 228 {
 229         struct hd_struct *p = dev_to_part(dev);
 230         return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
 231 }
 232
 233 ssize_t part_discard_alignment_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, "%u\n", p->discard_alignment);
 238 }
 239
 240 ssize_t part_stat_show(struct device *dev,
 241                        struct device_attribute *attr, char *buf)
 242 {
 243         struct hd_struct *p = dev_to_part(dev);
 244         int cpu;
 245
 246         cpu = part_stat_lock();
 247         part_round_stats(cpu, p);
 248         part_stat_unlock();
 249         return sprintf(buf,
 250                 "%8lu %8lu %8llu %8u "
 251                 "%8lu %8lu %8llu %8u "
 252                 "%8u %8u %8u"
 253                 "\n",
 254                 part_stat_read(p, ios[READ]),
 255                 part_stat_read(p, merges[READ]),
 256                 (unsigned long long)part_stat_read(p, sectors[READ]),
 257                 jiffies_to_msecs(part_stat_read(p, ticks[READ])),
 258                 part_stat_read(p, ios[WRITE]),
 259                 part_stat_read(p, merges[WRITE]),
 260                 (unsigned long long)part_stat_read(p, sectors[WRITE]),
 261                 jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
 262                 part_in_flight(p),
 263                 jiffies_to_msecs(part_stat_read(p, io_ticks)),
 264                 jiffies_to_msecs(part_stat_read(p, time_in_queue)));
 265 }
 266
 267 ssize_t part_inflight_show(struct device *dev,
 268                         struct device_attribute *attr, char *buf)
 269 {
 270         struct hd_struct *p = dev_to_part(dev);
 271
 272         return sprintf(buf, "%8u %8u\n", p->in_flight[0], p->in_flight[1]);
 273 }
 274
 275 #ifdef CONFIG_FAIL_MAKE_REQUEST
 276 ssize_t part_fail_show(struct device *dev,
 277                        struct device_attribute *attr, char *buf)
 278 {
 279         struct hd_struct *p = dev_to_part(dev);
 280
 281         return sprintf(buf, "%d\n", p->make_it_fail);
 282 }
 283
 284 ssize_t part_fail_store(struct device *dev,
 285                         struct device_attribute *attr,
 286                         const char *buf, size_t count)
 287 {
 288         struct hd_struct *p = dev_to_part(dev);
 289         int i;
 290
 291         if (count > 0 && sscanf(buf, "%d", &i) > 0)
 292                 p->make_it_fail = (i == 0) ? 0 : 1;
 293
 294         return count;
 295 }
 296 #endif
 297
 298 static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
 299 static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
 300 static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
 301 static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
 302 static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
 303                    NULL);
 304 static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
 305 static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
 306 #ifdef CONFIG_FAIL_MAKE_REQUEST
 307 static struct device_attribute dev_attr_fail =
 308         __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
 309 #endif
 310
 311 static struct attribute *part_attrs[] = {
 312         &dev_attr_partition.attr,
 313         &dev_attr_start.attr,
 314         &dev_attr_size.attr,
 315         &dev_attr_alignment_offset.attr,
 316         &dev_attr_discard_alignment.attr,
 317         &dev_attr_stat.attr,
 318         &dev_attr_inflight.attr,
 319 #ifdef CONFIG_FAIL_MAKE_REQUEST
 320         &dev_attr_fail.attr,
 321 #endif
 322         NULL
 323 };
 324
 325 static struct attribute_group part_attr_group = {
 326         .attrs = part_attrs,
 327 };
 328
 329 static const struct attribute_group *part_attr_groups[] = {
 330         &part_attr_group,
 331 #ifdef CONFIG_BLK_DEV_IO_TRACE
 332         &blk_trace_attr_group,
 333 #endif
 334         NULL
 335 };
 336
 337 static void part_release(struct device *dev)
 338 {
 339         struct hd_struct *p = dev_to_part(dev);
 340         free_part_stats(p);
 341         kfree(p);
 342 }
 343
 344 struct device_type part_type = {
 345         .name           = "partition",
 346         .groups         = part_attr_groups,
 347         .release        = part_release,
 348 };
 349
 350 static void delete_partition_rcu_cb(struct rcu_head *head)
 351 {
 352         struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
 353
 354         part->start_sect = 0;
 355         part->nr_sects = 0;
 356         part_stat_set_all(part, 0);
 357         put_device(part_to_dev(part));
 358 }
 359
 360 void delete_partition(struct gendisk *disk, int partno)
 361 {
 362         struct disk_part_tbl *ptbl = disk->part_tbl;
 363         struct hd_struct *part;
 364
 365         if (partno >= ptbl->len)
 366                 return;
 367
 368         part = ptbl->part[partno];
 369         if (!part)
 370                 return;
 371
 372         blk_free_devt(part_devt(part));
 373         rcu_assign_pointer(ptbl->part[partno], NULL);
 374         rcu_assign_pointer(ptbl->last_lookup, NULL);
 375         kobject_put(part->holder_dir);
 376         device_del(part_to_dev(part));
 377
 378         call_rcu(&part->rcu_head, delete_partition_rcu_cb);
 379 }
 380
 381 static ssize_t whole_disk_show(struct device *dev,
 382                                struct device_attribute *attr, char *buf)
 383 {
 384         return 0;
 385 }
 386 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
 387                    whole_disk_show, NULL);
 388
 389 struct hd_struct *add_partition(struct gendisk *disk, int partno,
 390                                 sector_t start, sector_t len, int flags)
 391 {
 392         struct hd_struct *p;
 393         dev_t devt = MKDEV(0, 0);
 394         struct device *ddev = disk_to_dev(disk);
 395         struct device *pdev;
 396         struct disk_part_tbl *ptbl;
 397         const char *dname;
 398         int err;
 399
 400         err = disk_expand_part_tbl(disk, partno);
 401         if (err)
 402                 return ERR_PTR(err);
 403         ptbl = disk->part_tbl;
 404
 405         if (ptbl->part[partno])
 406                 return ERR_PTR(-EBUSY);
 407
 408         p = kzalloc(sizeof(*p), GFP_KERNEL);
 409         if (!p)
 410                 return ERR_PTR(-EBUSY);
 411
 412         if (!init_part_stats(p)) {
 413                 err = -ENOMEM;
 414                 goto out_free;
 415         }
 416         pdev = part_to_dev(p);
 417
 418         p->start_sect = start;
 419         p->alignment_offset =
 420                 queue_limit_alignment_offset(&disk->queue->limits, start);
 421         p->discard_alignment =
 422                 queue_limit_discard_alignment(&disk->queue->limits, start);
 423         p->nr_sects = len;
 424         p->partno = partno;
 425         p->policy = get_disk_ro(disk);
 426
 427         dname = dev_name(ddev);
 428         if (isdigit(dname[strlen(dname) - 1]))
 429                 dev_set_name(pdev, "%sp%d", dname, partno);
 430         else
 431                 dev_set_name(pdev, "%s%d", dname, partno);
 432
 433         device_initialize(pdev);
 434         pdev->class = &block_class;
 435         pdev->type = &part_type;
 436         pdev->parent = ddev;
 437
 438         err = blk_alloc_devt(p, &devt);
 439         if (err)
 440                 goto out_free_stats;
 441         pdev->devt = devt;
 442
 443         /* delay uevent until 'holders' subdir is created */
 444         dev_set_uevent_suppress(pdev, 1);
 445         err = device_add(pdev);
 446         if (err)
 447                 goto out_put;
 448
 449         err = -ENOMEM;
 450         p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
 451         if (!p->holder_dir)
 452                 goto out_del;
 453
 454         dev_set_uevent_suppress(pdev, 0);
 455         if (flags & ADDPART_FLAG_WHOLEDISK) {
 456                 err = device_create_file(pdev, &dev_attr_whole_disk);
 457                 if (err)
 458                         goto out_del;
 459         }
 460
 461         /* everything is up and running, commence */
 462         INIT_RCU_HEAD(&p->rcu_head);
 463         rcu_assign_pointer(ptbl->part[partno], p);
 464
 465         /* suppress uevent if the disk supresses it */
 466         if (!dev_get_uevent_suppress(ddev))
 467                 kobject_uevent(&pdev->kobj, KOBJ_ADD);
 468
 469         return p;
 470
 471 out_free_stats:
 472         free_part_stats(p);
 473 out_free:
 474         kfree(p);
 475         return ERR_PTR(err);
 476 out_del:
 477         kobject_put(p->holder_dir);
 478         device_del(pdev);
 479 out_put:
 480         put_device(pdev);
 481         blk_free_devt(devt);
 482         return ERR_PTR(err);
 483 }
 484
 485 /* Not exported, helper to add_disk(). */
 486 void register_disk(struct gendisk *disk)
 487 {
 488         struct device *ddev = disk_to_dev(disk);
 489         struct block_device *bdev;
 490         struct disk_part_iter piter;
 491         struct hd_struct *part;
 492         int err;
 493
 494         ddev->parent = disk->driverfs_dev;
 495
 496         dev_set_name(ddev, disk->disk_name);
 497
 498         /* delay uevents, until we scanned partition table */
 499         dev_set_uevent_suppress(ddev, 1);
 500
 501         if (device_add(ddev))
 502                 return;
 503 #ifndef CONFIG_SYSFS_DEPRECATED
 504         err = sysfs_create_link(block_depr, &ddev->kobj,
 505                                 kobject_name(&ddev->kobj));
 506         if (err) {
 507                 device_del(ddev);
 508                 return;
 509         }
 510 #endif
 511         disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
 512         disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
 513
 514         /* No minors to use for partitions */
 515         if (!disk_partitionable(disk))
 516                 goto exit;
 517
 518         /* No such device (e.g., media were just removed) */
 519         if (!get_capacity(disk))
 520                 goto exit;
 521
 522         bdev = bdget_disk(disk, 0);
 523         if (!bdev)
 524                 goto exit;
 525
 526         bdev->bd_invalidated = 1;
 527         err = blkdev_get(bdev, FMODE_READ);
 528         if (err < 0)
 529                 goto exit;
 530         blkdev_put(bdev, FMODE_READ);
 531
 532 exit:
 533         /* announce disk after possible partitions are created */
 534         dev_set_uevent_suppress(ddev, 0);
 535         kobject_uevent(&ddev->kobj, KOBJ_ADD);
 536
 537         /* announce possible partitions */
 538         disk_part_iter_init(&piter, disk, 0);
 539         while ((part = disk_part_iter_next(&piter)))
 540                 kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
 541         disk_part_iter_exit(&piter);
 542 }
 543
 544 static bool disk_unlock_native_capacity(struct gendisk *disk)
 545 {
 546         const struct block_device_operations *bdops = disk->fops;
 547
 548         if (bdops->unlock_native_capacity &&
 549             !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
 550                 printk(KERN_CONT "enabling native capacity\n");
 551                 bdops->unlock_native_capacity(disk);
 552                 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
 553                 return true;
 554         } else {
 555                 printk(KERN_CONT "truncated\n");
 556                 return false;
 557         }
 558 }
 559
 560 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
 561 {
 562         struct parsed_partitions *state = NULL;
 563         struct disk_part_iter piter;
 564         struct hd_struct *part;
 565         int p, highest, res;
 566 rescan:
 567         if (state && !IS_ERR(state)) {
 568                 kfree(state);
 569                 state = NULL;
 570         }
 571
 572         if (bdev->bd_part_count)
 573                 return -EBUSY;
 574         res = invalidate_partition(disk, 0);
 575         if (res)
 576                 return res;
 577
 578         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
 579         while ((part = disk_part_iter_next(&piter)))
 580                 delete_partition(disk, part->partno);
 581         disk_part_iter_exit(&piter);
 582
 583         if (disk->fops->revalidate_disk)
 584                 disk->fops->revalidate_disk(disk);
 585         check_disk_size_change(disk, bdev);
 586         bdev->bd_invalidated = 0;
 587         if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
 588                 return 0;
 589         if (IS_ERR(state)) {
 590                 /*
 591                  * I/O error reading the partition table.  If any
 592                  * partition code tried to read beyond EOD, retry
 593                  * after unlocking native capacity.
 594                  */
 595                 if (PTR_ERR(state) == -ENOSPC) {
 596                         printk(KERN_WARNING "%s: partition table beyond EOD, ",
 597                                disk->disk_name);
 598                         if (disk_unlock_native_capacity(disk))
 599                                 goto rescan;
 600                 }
 601                 return -EIO;
 602         }
 603         /*
 604          * If any partition code tried to read beyond EOD, try
 605          * unlocking native capacity even if partition table is
 606          * sucessfully read as we could be missing some partitions.
 607          */
 608         if (state->access_beyond_eod) {
 609                 printk(KERN_WARNING
 610                        "%s: partition table partially beyond EOD, ",
 611                        disk->disk_name);
 612                 if (disk_unlock_native_capacity(disk))
 613                         goto rescan;
 614         }
 615
 616         /* tell userspace that the media / partition table may have changed */
 617         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
 618
 619         /* Detect the highest partition number and preallocate
 620          * disk->part_tbl.  This is an optimization and not strictly
 621          * necessary.
 622          */
 623         for (p = 1, highest = 0; p < state->limit; p++)
 624                 if (state->parts[p].size)
 625                         highest = p;
 626
 627         disk_expand_part_tbl(disk, highest);
 628
 629         /* add partitions */
 630         for (p = 1; p < state->limit; p++) {
 631                 sector_t size, from;
 632
 633                 size = state->parts[p].size;
 634                 if (!size)
 635                         continue;
 636
 637                 from = state->parts[p].from;
 638                 if (from >= get_capacity(disk)) {
 639                         printk(KERN_WARNING
 640                                "%s: p%d start %llu is beyond EOD, ",
 641                                disk->disk_name, p, (unsigned long long) from);
 642                         if (disk_unlock_native_capacity(disk))
 643                                 goto rescan;
 644                         continue;
 645                 }
 646
 647                 if (from + size > get_capacity(disk)) {
 648                         printk(KERN_WARNING
 649                                "%s: p%d size %llu extends beyond EOD, ",
 650                                disk->disk_name, p, (unsigned long long) size);
 651
 652                         if (disk_unlock_native_capacity(disk)) {
 653                                 /* free state and restart */
 654                                 goto rescan;
 655                         } else {
 656                                 /*
 657                                  * we can not ignore partitions of broken tables
 658                                  * created by for example camera firmware, but
 659                                  * we limit them to the end of the disk to avoid
 660                                  * creating invalid block devices
 661                                  */
 662                                 size = get_capacity(disk) - from;
 663                         }
 664                 }
 665                 part = add_partition(disk, p, from, size,
 666                                      state->parts[p].flags);
 667                 if (IS_ERR(part)) {
 668                         printk(KERN_ERR " %s: p%d could not be added: %ld\n",
 669                                disk->disk_name, p, -PTR_ERR(part));
 670                         continue;
 671                 }
 672 #ifdef CONFIG_BLK_DEV_MD
 673                 if (state->parts[p].flags & ADDPART_FLAG_RAID)
 674                         md_autodetect_dev(part_to_dev(part)->devt);
 675 #endif
 676         }
 677         kfree(state);
 678         return 0;
 679 }
 680
 681 unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
 682 {
 683         struct address_space *mapping = bdev->bd_inode->i_mapping;
 684         struct page *page;
 685
 686         page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
 687                                  NULL);
 688         if (!IS_ERR(page)) {
 689                 if (PageError(page))
 690                         goto fail;
 691                 p->v = page;
 692                 return (unsigned char *)page_address(page) +  ((n & ((1 << (PAGE_CACHE_SHIFT - 9)) - 1)) << 9);
 693 fail:
 694                 page_cache_release(page);
 695         }
 696         p->v = NULL;
 697         return NULL;
 698 }
 699
 700 EXPORT_SYMBOL(read_dev_sector);
 701
 702 void del_gendisk(struct gendisk *disk)
 703 {
 704         struct disk_part_iter piter;
 705         struct hd_struct *part;
 706
 707         /* invalidate stuff */
 708         disk_part_iter_init(&piter, disk,
 709                              DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
 710         while ((part = disk_part_iter_next(&piter))) {
 711                 invalidate_partition(disk, part->partno);
 712                 delete_partition(disk, part->partno);
 713         }
 714         disk_part_iter_exit(&piter);
 715
 716         invalidate_partition(disk, 0);
 717         blk_free_devt(disk_to_dev(disk)->devt);
 718         set_capacity(disk, 0);
 719         disk->flags &= ~GENHD_FL_UP;
 720         unlink_gendisk(disk);
 721         part_stat_set_all(&disk->part0, 0);
 722         disk->part0.stamp = 0;
 723
 724         kobject_put(disk->part0.holder_dir);
 725         kobject_put(disk->slave_dir);
 726         disk->driverfs_dev = NULL;
 727 #ifndef CONFIG_SYSFS_DEPRECATED
 728         sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
 729 #endif
 730         device_del(disk_to_dev(disk));
 731 }