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         err = hd_ref_init(p);
 364         if (err) {
 365                 if (flags & ADDPART_FLAG_WHOLEDISK)
 366                         goto out_remove_file;
 367                 goto out_del;
 368         }
 369
 370         /* everything is up and running, commence */
 371         rcu_assign_pointer(ptbl->part[partno], p);
 372
 373         /* suppress uevent if the disk suppresses it */
 374         if (!dev_get_uevent_suppress(ddev))
 375                 kobject_uevent(&pdev->kobj, KOBJ_ADD);
 376         return p;
 377
 378 out_free_info:
 379         free_part_info(p);
 380 out_free_stats:
 381         free_part_stats(p);
 382 out_free:
 383         kfree(p);
 384         return ERR_PTR(err);
 385 out_remove_file:
 386         device_remove_file(pdev, &dev_attr_whole_disk);
 387 out_del:
 388         kobject_put(p->holder_dir);
 389         device_del(pdev);
 390 out_put:
 391         put_device(pdev);
 392         blk_free_devt(devt);
 393         return ERR_PTR(err);
 394 }
 395
 396 static bool disk_unlock_native_capacity(struct gendisk *disk)
 397 {
 398         const struct block_device_operations *bdops = disk->fops;
 399
 400         if (bdops->unlock_native_capacity &&
 401             !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
 402                 printk(KERN_CONT "enabling native capacity\n");
 403                 bdops->unlock_native_capacity(disk);
 404                 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
 405                 return true;
 406         } else {
 407                 printk(KERN_CONT "truncated\n");
 408                 return false;
 409         }
 410 }
 411
 412 static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
 413 {
 414         struct disk_part_iter piter;
 415         struct hd_struct *part;
 416         int res;
 417
 418         if (bdev->bd_part_count || bdev->bd_super)
 419                 return -EBUSY;
 420         res = invalidate_partition(disk, 0);
 421         if (res)
 422                 return res;
 423
 424         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
 425         while ((part = disk_part_iter_next(&piter)))
 426                 delete_partition(disk, part->partno);
 427         disk_part_iter_exit(&piter);
 428
 429         return 0;
 430 }
 431
 432 static bool part_zone_aligned(struct gendisk *disk,
 433                               struct block_device *bdev,
 434                               sector_t from, sector_t size)
 435 {
 436         unsigned int zone_sectors = bdev_zone_sectors(bdev);
 437
 438         /*
 439          * If this function is called, then the disk is a zoned block device
 440          * (host-aware or host-managed). This can be detected even if the
 441          * zoned block device support is disabled (CONFIG_BLK_DEV_ZONED not
 442          * set). In this case, however, only host-aware devices will be seen
 443          * as a block device is not created for host-managed devices. Without
 444          * zoned block device support, host-aware drives can still be used as
 445          * regular block devices (no zone operation) and their zone size will
 446          * be reported as 0. Allow this case.
 447          */
 448         if (!zone_sectors)
 449                 return true;
 450
 451         /*
 452          * Check partition start and size alignement. If the drive has a
 453          * smaller last runt zone, ignore it and allow the partition to
 454          * use it. Check the zone size too: it should be a power of 2 number
 455          * of sectors.
 456          */
 457         if (WARN_ON_ONCE(!is_power_of_2(zone_sectors))) {
 458                 u32 rem;
 459
 460                 div_u64_rem(from, zone_sectors, &rem);
 461                 if (rem)
 462                         return false;
 463                 if ((from + size) < get_capacity(disk)) {
 464                         div_u64_rem(size, zone_sectors, &rem);
 465                         if (rem)
 466                                 return false;
 467                 }
 468
 469         } else {
 470
 471                 if (from & (zone_sectors - 1))
 472                         return false;
 473                 if ((from + size) < get_capacity(disk) &&
 474                     (size & (zone_sectors - 1)))
 475                         return false;
 476
 477         }
 478
 479         return true;
 480 }
 481
 482 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
 483 {
 484         struct parsed_partitions *state = NULL;
 485         struct hd_struct *part;
 486         int p, highest, res;
 487 rescan:
 488         if (state && !IS_ERR(state)) {
 489                 free_partitions(state);
 490                 state = NULL;
 491         }
 492
 493         res = drop_partitions(disk, bdev);
 494         if (res)
 495                 return res;
 496
 497         if (disk->fops->revalidate_disk)
 498                 disk->fops->revalidate_disk(disk);
 499         check_disk_size_change(disk, bdev);
 500         bdev->bd_invalidated = 0;
 501         if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
 502                 return 0;
 503         if (IS_ERR(state)) {
 504                 /*
 505                  * I/O error reading the partition table.  If any
 506                  * partition code tried to read beyond EOD, retry
 507                  * after unlocking native capacity.
 508                  */
 509                 if (PTR_ERR(state) == -ENOSPC) {
 510                         printk(KERN_WARNING "%s: partition table beyond EOD, ",
 511                                disk->disk_name);
 512                         if (disk_unlock_native_capacity(disk))
 513                                 goto rescan;
 514                 }
 515                 return -EIO;
 516         }
 517         /*
 518          * If any partition code tried to read beyond EOD, try
 519          * unlocking native capacity even if partition table is
 520          * successfully read as we could be missing some partitions.
 521          */
 522         if (state->access_beyond_eod) {
 523                 printk(KERN_WARNING
 524                        "%s: partition table partially beyond EOD, ",
 525                        disk->disk_name);
 526                 if (disk_unlock_native_capacity(disk))
 527                         goto rescan;
 528         }
 529
 530         /* tell userspace that the media / partition table may have changed */
 531         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
 532
 533         /* Detect the highest partition number and preallocate
 534          * disk->part_tbl.  This is an optimization and not strictly
 535          * necessary.
 536          */
 537         for (p = 1, highest = 0; p < state->limit; p++)
 538                 if (state->parts[p].size)
 539                         highest = p;
 540
 541         disk_expand_part_tbl(disk, highest);
 542
 543         /* add partitions */
 544         for (p = 1; p < state->limit; p++) {
 545                 sector_t size, from;
 546
 547                 size = state->parts[p].size;
 548                 if (!size)
 549                         continue;
 550
 551                 from = state->parts[p].from;
 552                 if (from >= get_capacity(disk)) {
 553                         printk(KERN_WARNING
 554                                "%s: p%d start %llu is beyond EOD, ",
 555                                disk->disk_name, p, (unsigned long long) from);
 556                         if (disk_unlock_native_capacity(disk))
 557                                 goto rescan;
 558                         continue;
 559                 }
 560
 561                 if (from + size > get_capacity(disk)) {
 562                         printk(KERN_WARNING
 563                                "%s: p%d size %llu extends beyond EOD, ",
 564                                disk->disk_name, p, (unsigned long long) size);
 565
 566                         if (disk_unlock_native_capacity(disk)) {
 567                                 /* free state and restart */
 568                                 goto rescan;
 569                         } else {
 570                                 /*
 571                                  * we can not ignore partitions of broken tables
 572                                  * created by for example camera firmware, but
 573                                  * we limit them to the end of the disk to avoid
 574                                  * creating invalid block devices
 575                                  */
 576                                 size = get_capacity(disk) - from;
 577                         }
 578                 }
 579
 580                 /*
 581                  * On a zoned block device, partitions should be aligned on the
 582                  * device zone size (i.e. zone boundary crossing not allowed).
 583                  * Otherwise, resetting the write pointer of the last zone of
 584                  * one partition may impact the following partition.
 585                  */
 586                 if (bdev_is_zoned(bdev) &&
 587                     !part_zone_aligned(disk, bdev, from, size)) {
 588                         printk(KERN_WARNING
 589                                "%s: p%d start %llu+%llu is not zone aligned\n",
 590                                disk->disk_name, p, (unsigned long long) from,
 591                                (unsigned long long) size);
 592                         continue;
 593                 }
 594
 595                 part = add_partition(disk, p, from, size,
 596                                      state->parts[p].flags,
 597                                      &state->parts[p].info);
 598                 if (IS_ERR(part)) {
 599                         printk(KERN_ERR " %s: p%d could not be added: %ld\n",
 600                                disk->disk_name, p, -PTR_ERR(part));
 601                         continue;
 602                 }
 603 #ifdef CONFIG_BLK_DEV_MD
 604                 if (state->parts[p].flags & ADDPART_FLAG_RAID)
 605                         md_autodetect_dev(part_to_dev(part)->devt);
 606 #endif
 607         }
 608         free_partitions(state);
 609         return 0;
 610 }
 611
 612 int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
 613 {
 614         int res;
 615
 616         if (!bdev->bd_invalidated)
 617                 return 0;
 618
 619         res = drop_partitions(disk, bdev);
 620         if (res)
 621                 return res;
 622
 623         set_capacity(disk, 0);
 624         check_disk_size_change(disk, bdev);
 625         bdev->bd_invalidated = 0;
 626         /* tell userspace that the media / partition table may have changed */
 627         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
 628
 629         return 0;
 630 }
 631
 632 unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
 633 {
 634         struct address_space *mapping = bdev->bd_inode->i_mapping;
 635         struct page *page;
 636
 637         page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_SHIFT-9)), NULL);
 638         if (!IS_ERR(page)) {
 639                 if (PageError(page))
 640                         goto fail;
 641                 p->v = page;
 642                 return (unsigned char *)page_address(page) +  ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << 9);
 643 fail:
 644                 put_page(page);
 645         }
 646         p->v = NULL;
 647         return NULL;
 648 }
 649
 650 EXPORT_SYMBOL(read_dev_sector);