block/partition-generic.c

   1 /*
   2  *  Code extracted from drivers/block/genhd.c
   3  *  Copyright (C) 1991-1998  Linus Torvalds
   4  *  Re-organised Feb 1998 Russell King
   5  *
   6  *  We now have independent partition support from the
   7  *  block drivers, which allows all the partition code to
   8  *  be grouped in one location, and it to be mostly self
   9  *  contained.
  10  */
  11
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/fs.h>
  15 #include <linux/slab.h>
  16 #include <linux/kmod.h>
  17 #include <linux/ctype.h>
  18 #include <linux/genhd.h>
  19 #include <linux/blktrace_api.h>
  20
  21 #include "partitions/check.h"
  22
  23 #ifdef CONFIG_BLK_DEV_MD
  24 extern void md_autodetect_dev(dev_t dev);
  25 #endif
  26
  27 /*
  28  * disk_name() is used by partition check code and the genhd driver.
  29  * It formats the devicename of the indicated disk into
  30  * the supplied buffer (of size at least 32), and returns
  31  * a pointer to that same buffer (for convenience).
  32  */
  33
  34 char *disk_name(struct gendisk *hd, int partno, char *buf)
  35 {
  36         if (!partno)
  37                 snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
  38         else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
  39                 snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
  40         else
  41                 snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
  42
  43         return buf;
  44 }
  45
  46 const char *bdevname(struct block_device *bdev, char *buf)
  47 {
  48         return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
  49 }
  50
  51 EXPORT_SYMBOL(bdevname);
  52
  53 /*
  54  * There's very little reason to use this, you should really
  55  * have a struct block_device just about everywhere and use
  56  * bdevname() instead.
  57  */
  58 const char *__bdevname(dev_t dev, char *buffer)
  59 {
  60         scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
  61                                 MAJOR(dev), MINOR(dev));
  62         return buffer;
  63 }
  64
  65 EXPORT_SYMBOL(__bdevname);
  66
  67 static ssize_t part_partition_show(struct device *dev,
  68                                    struct device_attribute *attr, char *buf)
  69 {
  70         struct hd_struct *p = dev_to_part(dev);
  71
  72         return sprintf(buf, "%d\n", p->partno);
  73 }
  74
  75 static ssize_t part_start_show(struct device *dev,
  76                                struct device_attribute *attr, char *buf)
  77 {
  78         struct hd_struct *p = dev_to_part(dev);
  79
  80         return sprintf(buf, "%llu\n",(unsigned long long)p->start_sect);
  81 }
  82
  83 ssize_t part_size_show(struct device *dev,
  84                        struct device_attribute *attr, char *buf)
  85 {
  86         struct hd_struct *p = dev_to_part(dev);
  87         return sprintf(buf, "%llu\n",(unsigned long long)part_nr_sects_read(p));
  88 }
  89
  90 static ssize_t part_ro_show(struct device *dev,
  91                             struct device_attribute *attr, char *buf)
  92 {
  93         struct hd_struct *p = dev_to_part(dev);
  94         return sprintf(buf, "%d\n", p->policy ? 1 : 0);
  95 }
  96
  97 static ssize_t part_alignment_offset_show(struct device *dev,
  98                                           struct device_attribute *attr, char *buf)
  99 {
 100         struct hd_struct *p = dev_to_part(dev);
 101         return sprintf(buf, "%llu\n", (unsigned long long)p->alignment_offset);
 102 }
 103
 104 static ssize_t part_discard_alignment_show(struct device *dev,
 105                                            struct device_attribute *attr, char *buf)
 106 {
 107         struct hd_struct *p = dev_to_part(dev);
 108         return sprintf(buf, "%u\n", p->discard_alignment);
 109 }
 110
 111 ssize_t part_stat_show(struct device *dev,
 112                        struct device_attribute *attr, char *buf)
 113 {
 114         struct hd_struct *p = dev_to_part(dev);
 115         int cpu;
 116
 117         cpu = part_stat_lock();
 118         part_round_stats(cpu, p);
 119         part_stat_unlock();
 120         return sprintf(buf,
 121                 "%8lu %8lu %8llu %8u "
 122                 "%8lu %8lu %8llu %8u "
 123                 "%8u %8u %8u"
 124                 "\n",
 125                 part_stat_read(p, ios[READ]),
 126                 part_stat_read(p, merges[READ]),
 127                 (unsigned long long)part_stat_read(p, sectors[READ]),
 128                 jiffies_to_msecs(part_stat_read(p, ticks[READ])),
 129                 part_stat_read(p, ios[WRITE]),
 130                 part_stat_read(p, merges[WRITE]),
 131                 (unsigned long long)part_stat_read(p, sectors[WRITE]),
 132                 jiffies_to_msecs(part_stat_read(p, ticks[WRITE])),
 133                 part_in_flight(p),
 134                 jiffies_to_msecs(part_stat_read(p, io_ticks)),
 135                 jiffies_to_msecs(part_stat_read(p, time_in_queue)));
 136 }
 137
 138 ssize_t part_inflight_show(struct device *dev,
 139                         struct device_attribute *attr, char *buf)
 140 {
 141         struct hd_struct *p = dev_to_part(dev);
 142
 143         return sprintf(buf, "%8u %8u\n", atomic_read(&p->in_flight[0]),
 144                 atomic_read(&p->in_flight[1]));
 145 }
 146
 147 #ifdef CONFIG_FAIL_MAKE_REQUEST
 148 ssize_t part_fail_show(struct device *dev,
 149                        struct device_attribute *attr, char *buf)
 150 {
 151         struct hd_struct *p = dev_to_part(dev);
 152
 153         return sprintf(buf, "%d\n", p->make_it_fail);
 154 }
 155
 156 ssize_t part_fail_store(struct device *dev,
 157                         struct device_attribute *attr,
 158                         const char *buf, size_t count)
 159 {
 160         struct hd_struct *p = dev_to_part(dev);
 161         int i;
 162
 163         if (count > 0 && sscanf(buf, "%d", &i) > 0)
 164                 p->make_it_fail = (i == 0) ? 0 : 1;
 165
 166         return count;
 167 }
 168 #endif
 169
 170 static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
 171 static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
 172 static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
 173 static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
 174 static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
 175 static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
 176                    NULL);
 177 static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
 178 static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
 179 #ifdef CONFIG_FAIL_MAKE_REQUEST
 180 static struct device_attribute dev_attr_fail =
 181         __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
 182 #endif
 183
 184 static struct attribute *part_attrs[] = {
 185         &dev_attr_partition.attr,
 186         &dev_attr_start.attr,
 187         &dev_attr_size.attr,
 188         &dev_attr_ro.attr,
 189         &dev_attr_alignment_offset.attr,
 190         &dev_attr_discard_alignment.attr,
 191         &dev_attr_stat.attr,
 192         &dev_attr_inflight.attr,
 193 #ifdef CONFIG_FAIL_MAKE_REQUEST
 194         &dev_attr_fail.attr,
 195 #endif
 196         NULL
 197 };
 198
 199 static struct attribute_group part_attr_group = {
 200         .attrs = part_attrs,
 201 };
 202
 203 static const struct attribute_group *part_attr_groups[] = {
 204         &part_attr_group,
 205 #ifdef CONFIG_BLK_DEV_IO_TRACE
 206         &blk_trace_attr_group,
 207 #endif
 208         NULL
 209 };
 210
 211 static void part_release(struct device *dev)
 212 {
 213         struct hd_struct *p = dev_to_part(dev);
 214         blk_free_devt(dev->devt);
 215         hd_free_part(p);
 216         kfree(p);
 217 }
 218
 219 static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
 220 {
 221         struct hd_struct *part = dev_to_part(dev);
 222
 223         add_uevent_var(env, "PARTN=%u", part->partno);
 224         if (part->info && part->info->volname[0])
 225                 add_uevent_var(env, "PARTNAME=%s", part->info->volname);
 226         return 0;
 227 }
 228
 229 struct device_type part_type = {
 230         .name           = "partition",
 231         .groups         = part_attr_groups,
 232         .release        = part_release,
 233         .uevent         = part_uevent,
 234 };
 235
 236 static void delete_partition_rcu_cb(struct rcu_head *head)
 237 {
 238         struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
 239
 240         part->start_sect = 0;
 241         part->nr_sects = 0;
 242         part_stat_set_all(part, 0);
 243         put_device(part_to_dev(part));
 244 }
 245
 246 void __delete_partition(struct percpu_ref *ref)
 247 {
 248         struct hd_struct *part = container_of(ref, struct hd_struct, ref);
 249         call_rcu(&part->rcu_head, delete_partition_rcu_cb);
 250 }
 251
 252 void delete_partition(struct gendisk *disk, int partno)
 253 {
 254         struct disk_part_tbl *ptbl = disk->part_tbl;
 255         struct hd_struct *part;
 256
 257         if (partno >= ptbl->len)
 258                 return;
 259
 260         part = ptbl->part[partno];
 261         if (!part)
 262                 return;
 263
 264         rcu_assign_pointer(ptbl->part[partno], NULL);
 265         rcu_assign_pointer(ptbl->last_lookup, NULL);
 266         kobject_put(part->holder_dir);
 267         device_del(part_to_dev(part));
 268
 269         hd_struct_kill(part);
 270 }
 271
 272 static ssize_t whole_disk_show(struct device *dev,
 273                                struct device_attribute *attr, char *buf)
 274 {
 275         return 0;
 276 }
 277 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
 278                    whole_disk_show, NULL);
 279
 280 struct hd_struct *add_partition(struct gendisk *disk, int partno,
 281                                 sector_t start, sector_t len, int flags,
 282                                 struct partition_meta_info *info)
 283 {
 284         struct hd_struct *p;
 285         dev_t devt = MKDEV(0, 0);
 286         struct device *ddev = disk_to_dev(disk);
 287         struct device *pdev;
 288         struct disk_part_tbl *ptbl;
 289         const char *dname;
 290         int err;
 291
 292         err = disk_expand_part_tbl(disk, partno);
 293         if (err)
 294                 return ERR_PTR(err);
 295         ptbl = disk->part_tbl;
 296
 297         if (ptbl->part[partno])
 298                 return ERR_PTR(-EBUSY);
 299
 300         p = kzalloc(sizeof(*p), GFP_KERNEL);
 301         if (!p)
 302                 return ERR_PTR(-EBUSY);
 303
 304         if (!init_part_stats(p)) {
 305                 err = -ENOMEM;
 306                 goto out_free;
 307         }
 308
 309         seqcount_init(&p->nr_sects_seq);
 310         pdev = part_to_dev(p);
 311
 312         p->start_sect = start;
 313         p->alignment_offset =
 314                 queue_limit_alignment_offset(&disk->queue->limits, start);
 315         p->discard_alignment =
 316                 queue_limit_discard_alignment(&disk->queue->limits, start);
 317         p->nr_sects = len;
 318         p->partno = partno;
 319         p->policy = get_disk_ro(disk);
 320
 321         if (info) {
 322                 struct partition_meta_info *pinfo = alloc_part_info(disk);
 323                 if (!pinfo)
 324                         goto out_free_stats;
 325                 memcpy(pinfo, info, sizeof(*info));
 326                 p->info = pinfo;
 327         }
 328
 329         dname = dev_name(ddev);
 330         if (isdigit(dname[strlen(dname) - 1]))
 331                 dev_set_name(pdev, "%sp%d", dname, partno);
 332         else
 333                 dev_set_name(pdev, "%s%d", dname, partno);
 334
 335         device_initialize(pdev);
 336         pdev->class = &block_class;
 337         pdev->type = &part_type;
 338         pdev->parent = ddev;
 339
 340         err = blk_alloc_devt(p, &devt);
 341         if (err)
 342                 goto out_free_info;
 343         pdev->devt = devt;
 344
 345         /* delay uevent until 'holders' subdir is created */
 346         dev_set_uevent_suppress(pdev, 1);
 347         err = device_add(pdev);
 348         if (err)
 349                 goto out_put;
 350
 351         err = -ENOMEM;
 352         p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
 353         if (!p->holder_dir)
 354                 goto out_del;
 355
 356         dev_set_uevent_suppress(pdev, 0);
 357         if (flags & ADDPART_FLAG_WHOLEDISK) {
 358                 err = device_create_file(pdev, &dev_attr_whole_disk);
 359                 if (err)
 360                         goto out_del;
 361         }
 362
 363         /* everything is up and running, commence */
 364         rcu_assign_pointer(ptbl->part[partno], p);
 365
 366         /* suppress uevent if the disk suppresses it */
 367         if (!dev_get_uevent_suppress(ddev))
 368                 kobject_uevent(&pdev->kobj, KOBJ_ADD);
 369
 370         if (!hd_ref_init(p))
 371                 return p;
 372
 373 out_free_info:
 374         free_part_info(p);
 375 out_free_stats:
 376         free_part_stats(p);
 377 out_free:
 378         kfree(p);
 379         return ERR_PTR(err);
 380 out_del:
 381         kobject_put(p->holder_dir);
 382         device_del(pdev);
 383 out_put:
 384         put_device(pdev);
 385         blk_free_devt(devt);
 386         return ERR_PTR(err);
 387 }
 388
 389 static bool disk_unlock_native_capacity(struct gendisk *disk)
 390 {
 391         const struct block_device_operations *bdops = disk->fops;
 392
 393         if (bdops->unlock_native_capacity &&
 394             !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
 395                 printk(KERN_CONT "enabling native capacity\n");
 396                 bdops->unlock_native_capacity(disk);
 397                 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
 398                 return true;
 399         } else {
 400                 printk(KERN_CONT "truncated\n");
 401                 return false;
 402         }
 403 }
 404
 405 static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
 406 {
 407         struct disk_part_iter piter;
 408         struct hd_struct *part;
 409         int res;
 410
 411         if (bdev->bd_part_count || bdev->bd_super)
 412                 return -EBUSY;
 413         res = invalidate_partition(disk, 0);
 414         if (res)
 415                 return res;
 416
 417         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
 418         while ((part = disk_part_iter_next(&piter)))
 419                 delete_partition(disk, part->partno);
 420         disk_part_iter_exit(&piter);
 421
 422         return 0;
 423 }
 424
 425 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
 426 {
 427         struct parsed_partitions *state = NULL;
 428         struct hd_struct *part;
 429         int p, highest, res;
 430 rescan:
 431         if (state && !IS_ERR(state)) {
 432                 free_partitions(state);
 433                 state = NULL;
 434         }
 435
 436         res = drop_partitions(disk, bdev);
 437         if (res)
 438                 return res;
 439
 440         if (disk->fops->revalidate_disk)
 441                 disk->fops->revalidate_disk(disk);
 442         blk_integrity_revalidate(disk);
 443         check_disk_size_change(disk, bdev);
 444         bdev->bd_invalidated = 0;
 445         if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
 446                 return 0;
 447         if (IS_ERR(state)) {
 448                 /*
 449                  * I/O error reading the partition table.  If any
 450                  * partition code tried to read beyond EOD, retry
 451                  * after unlocking native capacity.
 452                  */
 453                 if (PTR_ERR(state) == -ENOSPC) {
 454                         printk(KERN_WARNING "%s: partition table beyond EOD, ",
 455                                disk->disk_name);
 456                         if (disk_unlock_native_capacity(disk))
 457                                 goto rescan;
 458                 }
 459                 return -EIO;
 460         }
 461         /*
 462          * If any partition code tried to read beyond EOD, try
 463          * unlocking native capacity even if partition table is
 464          * successfully read as we could be missing some partitions.
 465          */
 466         if (state->access_beyond_eod) {
 467                 printk(KERN_WARNING
 468                        "%s: partition table partially beyond EOD, ",
 469                        disk->disk_name);
 470                 if (disk_unlock_native_capacity(disk))
 471                         goto rescan;
 472         }
 473
 474         /* tell userspace that the media / partition table may have changed */
 475         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
 476
 477         /* Detect the highest partition number and preallocate
 478          * disk->part_tbl.  This is an optimization and not strictly
 479          * necessary.
 480          */
 481         for (p = 1, highest = 0; p < state->limit; p++)
 482                 if (state->parts[p].size)
 483                         highest = p;
 484
 485         disk_expand_part_tbl(disk, highest);
 486
 487         /* add partitions */
 488         for (p = 1; p < state->limit; p++) {
 489                 sector_t size, from;
 490                 struct partition_meta_info *info = NULL;
 491
 492                 size = state->parts[p].size;
 493                 if (!size)
 494                         continue;
 495
 496                 from = state->parts[p].from;
 497                 if (from >= get_capacity(disk)) {
 498                         printk(KERN_WARNING
 499                                "%s: p%d start %llu is beyond EOD, ",
 500                                disk->disk_name, p, (unsigned long long) from);
 501                         if (disk_unlock_native_capacity(disk))
 502                                 goto rescan;
 503                         continue;
 504                 }
 505
 506                 if (from + size > get_capacity(disk)) {
 507                         printk(KERN_WARNING
 508                                "%s: p%d size %llu extends beyond EOD, ",
 509                                disk->disk_name, p, (unsigned long long) size);
 510
 511                         if (disk_unlock_native_capacity(disk)) {
 512                                 /* free state and restart */
 513                                 goto rescan;
 514                         } else {
 515                                 /*
 516                                  * we can not ignore partitions of broken tables
 517                                  * created by for example camera firmware, but
 518                                  * we limit them to the end of the disk to avoid
 519                                  * creating invalid block devices
 520                                  */
 521                                 size = get_capacity(disk) - from;
 522                         }
 523                 }
 524
 525                 if (state->parts[p].has_info)
 526                         info = &state->parts[p].info;
 527                 part = add_partition(disk, p, from, size,
 528                                      state->parts[p].flags,
 529                                      &state->parts[p].info);
 530                 if (IS_ERR(part)) {
 531                         printk(KERN_ERR " %s: p%d could not be added: %ld\n",
 532                                disk->disk_name, p, -PTR_ERR(part));
 533                         continue;
 534                 }
 535 #ifdef CONFIG_BLK_DEV_MD
 536                 if (state->parts[p].flags & ADDPART_FLAG_RAID)
 537                         md_autodetect_dev(part_to_dev(part)->devt);
 538 #endif
 539         }
 540         free_partitions(state);
 541         return 0;
 542 }
 543
 544 int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
 545 {
 546         int res;
 547
 548         if (!bdev->bd_invalidated)
 549                 return 0;
 550
 551         res = drop_partitions(disk, bdev);
 552         if (res)
 553                 return res;
 554
 555         set_capacity(disk, 0);
 556         check_disk_size_change(disk, bdev);
 557         bdev->bd_invalidated = 0;
 558         /* tell userspace that the media / partition table may have changed */
 559         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
 560
 561         return 0;
 562 }
 563
 564 unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
 565 {
 566         struct address_space *mapping = bdev->bd_inode->i_mapping;
 567         struct page *page;
 568
 569         page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
 570                                  NULL);
 571         if (!IS_ERR(page)) {
 572                 if (PageError(page))
 573                         goto fail;
 574                 p->v = page;
 575                 return (unsigned char *)page_address(page) +  ((n & ((1 << (PAGE_CACHE_SHIFT - 9)) - 1)) << 9);
 576 fail:
 577                 page_cache_release(page);
 578         }
 579         p->v = NULL;
 580         return NULL;
 581 }
 582
 583 EXPORT_SYMBOL(read_dev_sector);