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