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         free_part_stats(p);
 216         free_part_info(p);
 217         kfree(p);
 218 }
 219
 220 struct device_type part_type = {
 221         .name           = "partition",
 222         .groups         = part_attr_groups,
 223         .release        = part_release,
 224 };
 225
 226 static void delete_partition_rcu_cb(struct rcu_head *head)
 227 {
 228         struct hd_struct *part = container_of(head, struct hd_struct, rcu_head);
 229
 230         part->start_sect = 0;
 231         part->nr_sects = 0;
 232         part_stat_set_all(part, 0);
 233         put_device(part_to_dev(part));
 234 }
 235
 236 void __delete_partition(struct hd_struct *part)
 237 {
 238         call_rcu(&part->rcu_head, delete_partition_rcu_cb);
 239 }
 240
 241 void delete_partition(struct gendisk *disk, int partno)
 242 {
 243         struct disk_part_tbl *ptbl = disk->part_tbl;
 244         struct hd_struct *part;
 245
 246         if (partno >= ptbl->len)
 247                 return;
 248
 249         part = ptbl->part[partno];
 250         if (!part)
 251                 return;
 252
 253         rcu_assign_pointer(ptbl->part[partno], NULL);
 254         rcu_assign_pointer(ptbl->last_lookup, NULL);
 255         kobject_put(part->holder_dir);
 256         device_del(part_to_dev(part));
 257
 258         hd_struct_put(part);
 259 }
 260
 261 static ssize_t whole_disk_show(struct device *dev,
 262                                struct device_attribute *attr, char *buf)
 263 {
 264         return 0;
 265 }
 266 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
 267                    whole_disk_show, NULL);
 268
 269 struct hd_struct *add_partition(struct gendisk *disk, int partno,
 270                                 sector_t start, sector_t len, int flags,
 271                                 struct partition_meta_info *info)
 272 {
 273         struct hd_struct *p;
 274         dev_t devt = MKDEV(0, 0);
 275         struct device *ddev = disk_to_dev(disk);
 276         struct device *pdev;
 277         struct disk_part_tbl *ptbl;
 278         const char *dname;
 279         int err;
 280
 281         err = disk_expand_part_tbl(disk, partno);
 282         if (err)
 283                 return ERR_PTR(err);
 284         ptbl = disk->part_tbl;
 285
 286         if (ptbl->part[partno])
 287                 return ERR_PTR(-EBUSY);
 288
 289         p = kzalloc(sizeof(*p), GFP_KERNEL);
 290         if (!p)
 291                 return ERR_PTR(-EBUSY);
 292
 293         if (!init_part_stats(p)) {
 294                 err = -ENOMEM;
 295                 goto out_free;
 296         }
 297
 298         seqcount_init(&p->nr_sects_seq);
 299         pdev = part_to_dev(p);
 300
 301         p->start_sect = start;
 302         p->alignment_offset =
 303                 queue_limit_alignment_offset(&disk->queue->limits, start);
 304         p->discard_alignment =
 305                 queue_limit_discard_alignment(&disk->queue->limits, start);
 306         p->nr_sects = len;
 307         p->partno = partno;
 308         p->policy = get_disk_ro(disk);
 309
 310         if (info) {
 311                 struct partition_meta_info *pinfo = alloc_part_info(disk);
 312                 if (!pinfo)
 313                         goto out_free_stats;
 314                 memcpy(pinfo, info, sizeof(*info));
 315                 p->info = pinfo;
 316         }
 317
 318         dname = dev_name(ddev);
 319         if (isdigit(dname[strlen(dname) - 1]))
 320                 dev_set_name(pdev, "%sp%d", dname, partno);
 321         else
 322                 dev_set_name(pdev, "%s%d", dname, partno);
 323
 324         device_initialize(pdev);
 325         pdev->class = &block_class;
 326         pdev->type = &part_type;
 327         pdev->parent = ddev;
 328
 329         err = blk_alloc_devt(p, &devt);
 330         if (err)
 331                 goto out_free_info;
 332         pdev->devt = devt;
 333
 334         /* delay uevent until 'holders' subdir is created */
 335         dev_set_uevent_suppress(pdev, 1);
 336         err = device_add(pdev);
 337         if (err)
 338                 goto out_put;
 339
 340         err = -ENOMEM;
 341         p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
 342         if (!p->holder_dir)
 343                 goto out_del;
 344
 345         dev_set_uevent_suppress(pdev, 0);
 346         if (flags & ADDPART_FLAG_WHOLEDISK) {
 347                 err = device_create_file(pdev, &dev_attr_whole_disk);
 348                 if (err)
 349                         goto out_del;
 350         }
 351
 352         /* everything is up and running, commence */
 353         rcu_assign_pointer(ptbl->part[partno], p);
 354
 355         /* suppress uevent if the disk suppresses it */
 356         if (!dev_get_uevent_suppress(ddev))
 357                 kobject_uevent(&pdev->kobj, KOBJ_ADD);
 358
 359         hd_ref_init(p);
 360         return p;
 361
 362 out_free_info:
 363         free_part_info(p);
 364 out_free_stats:
 365         free_part_stats(p);
 366 out_free:
 367         kfree(p);
 368         return ERR_PTR(err);
 369 out_del:
 370         kobject_put(p->holder_dir);
 371         device_del(pdev);
 372 out_put:
 373         put_device(pdev);
 374         blk_free_devt(devt);
 375         return ERR_PTR(err);
 376 }
 377
 378 static bool disk_unlock_native_capacity(struct gendisk *disk)
 379 {
 380         const struct block_device_operations *bdops = disk->fops;
 381
 382         if (bdops->unlock_native_capacity &&
 383             !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
 384                 printk(KERN_CONT "enabling native capacity\n");
 385                 bdops->unlock_native_capacity(disk);
 386                 disk->flags |= GENHD_FL_NATIVE_CAPACITY;
 387                 return true;
 388         } else {
 389                 printk(KERN_CONT "truncated\n");
 390                 return false;
 391         }
 392 }
 393
 394 static int drop_partitions(struct gendisk *disk, struct block_device *bdev)
 395 {
 396         struct disk_part_iter piter;
 397         struct hd_struct *part;
 398         int res;
 399
 400         if (bdev->bd_part_count)
 401                 return -EBUSY;
 402         res = invalidate_partition(disk, 0);
 403         if (res)
 404                 return res;
 405
 406         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
 407         while ((part = disk_part_iter_next(&piter)))
 408                 delete_partition(disk, part->partno);
 409         disk_part_iter_exit(&piter);
 410
 411         return 0;
 412 }
 413
 414 int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
 415 {
 416         struct parsed_partitions *state = NULL;
 417         struct hd_struct *part;
 418         int p, highest, res;
 419 rescan:
 420         if (state && !IS_ERR(state)) {
 421                 free_partitions(state);
 422                 state = NULL;
 423         }
 424
 425         res = drop_partitions(disk, bdev);
 426         if (res)
 427                 return res;
 428
 429         if (disk->fops->revalidate_disk)
 430                 disk->fops->revalidate_disk(disk);
 431         check_disk_size_change(disk, bdev);
 432         bdev->bd_invalidated = 0;
 433         if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
 434                 return 0;
 435         if (IS_ERR(state)) {
 436                 /*
 437                  * I/O error reading the partition table.  If any
 438                  * partition code tried to read beyond EOD, retry
 439                  * after unlocking native capacity.
 440                  */
 441                 if (PTR_ERR(state) == -ENOSPC) {
 442                         printk(KERN_WARNING "%s: partition table beyond EOD, ",
 443                                disk->disk_name);
 444                         if (disk_unlock_native_capacity(disk))
 445                                 goto rescan;
 446                 }
 447                 return -EIO;
 448         }
 449         /*
 450          * If any partition code tried to read beyond EOD, try
 451          * unlocking native capacity even if partition table is
 452          * successfully read as we could be missing some partitions.
 453          */
 454         if (state->access_beyond_eod) {
 455                 printk(KERN_WARNING
 456                        "%s: partition table partially beyond EOD, ",
 457                        disk->disk_name);
 458                 if (disk_unlock_native_capacity(disk))
 459                         goto rescan;
 460         }
 461
 462         /* tell userspace that the media / partition table may have changed */
 463         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
 464
 465         /* Detect the highest partition number and preallocate
 466          * disk->part_tbl.  This is an optimization and not strictly
 467          * necessary.
 468          */
 469         for (p = 1, highest = 0; p < state->limit; p++)
 470                 if (state->parts[p].size)
 471                         highest = p;
 472
 473         disk_expand_part_tbl(disk, highest);
 474
 475         /* add partitions */
 476         for (p = 1; p < state->limit; p++) {
 477                 sector_t size, from;
 478                 struct partition_meta_info *info = NULL;
 479
 480                 size = state->parts[p].size;
 481                 if (!size)
 482                         continue;
 483
 484                 from = state->parts[p].from;
 485                 if (from >= get_capacity(disk)) {
 486                         printk(KERN_WARNING
 487                                "%s: p%d start %llu is beyond EOD, ",
 488                                disk->disk_name, p, (unsigned long long) from);
 489                         if (disk_unlock_native_capacity(disk))
 490                                 goto rescan;
 491                         continue;
 492                 }
 493
 494                 if (from + size > get_capacity(disk)) {
 495                         printk(KERN_WARNING
 496                                "%s: p%d size %llu extends beyond EOD, ",
 497                                disk->disk_name, p, (unsigned long long) size);
 498
 499                         if (disk_unlock_native_capacity(disk)) {
 500                                 /* free state and restart */
 501                                 goto rescan;
 502                         } else {
 503                                 /*
 504                                  * we can not ignore partitions of broken tables
 505                                  * created by for example camera firmware, but
 506                                  * we limit them to the end of the disk to avoid
 507                                  * creating invalid block devices
 508                                  */
 509                                 size = get_capacity(disk) - from;
 510                         }
 511                 }
 512
 513                 if (state->parts[p].has_info)
 514                         info = &state->parts[p].info;
 515                 part = add_partition(disk, p, from, size,
 516                                      state->parts[p].flags,
 517                                      &state->parts[p].info);
 518                 if (IS_ERR(part)) {
 519                         printk(KERN_ERR " %s: p%d could not be added: %ld\n",
 520                                disk->disk_name, p, -PTR_ERR(part));
 521                         continue;
 522                 }
 523 #ifdef CONFIG_BLK_DEV_MD
 524                 if (state->parts[p].flags & ADDPART_FLAG_RAID)
 525                         md_autodetect_dev(part_to_dev(part)->devt);
 526 #endif
 527         }
 528         free_partitions(state);
 529         return 0;
 530 }
 531
 532 int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
 533 {
 534         int res;
 535
 536         if (!bdev->bd_invalidated)
 537                 return 0;
 538
 539         res = drop_partitions(disk, bdev);
 540         if (res)
 541                 return res;
 542
 543         set_capacity(disk, 0);
 544         check_disk_size_change(disk, bdev);
 545         bdev->bd_invalidated = 0;
 546         /* tell userspace that the media / partition table may have changed */
 547         kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
 548
 549         return 0;
 550 }
 551
 552 unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
 553 {
 554         struct address_space *mapping = bdev->bd_inode->i_mapping;
 555         struct page *page;
 556
 557         page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
 558                                  NULL);
 559         if (!IS_ERR(page)) {
 560                 if (PageError(page))
 561                         goto fail;
 562                 p->v = page;
 563                 return (unsigned char *)page_address(page) +  ((n & ((1 << (PAGE_CACHE_SHIFT - 9)) - 1)) << 9);
 564 fail:
 565                 page_cache_release(page);
 566         }
 567         p->v = NULL;
 568         return NULL;
 569 }
 570
 571 EXPORT_SYMBOL(read_dev_sector);