linux/block/partition-generic.c
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   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
  24extern 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
  34char *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
  46const char *bdevname(struct block_device *bdev, char *buf)
  47{
  48        return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
  49}
  50
  51EXPORT_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 */
  58const 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
  65EXPORT_SYMBOL(__bdevname);
  66
  67static 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
  75static 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
  83ssize_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
  90static 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
  97static 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
 104static 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
 111ssize_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
 138ssize_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
 148ssize_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
 156ssize_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
 170static DEVICE_ATTR(partition, S_IRUGO, part_partition_show, NULL);
 171static DEVICE_ATTR(start, S_IRUGO, part_start_show, NULL);
 172static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
 173static DEVICE_ATTR(ro, S_IRUGO, part_ro_show, NULL);
 174static DEVICE_ATTR(alignment_offset, S_IRUGO, part_alignment_offset_show, NULL);
 175static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
 176                   NULL);
 177static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
 178static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
 179#ifdef CONFIG_FAIL_MAKE_REQUEST
 180static struct device_attribute dev_attr_fail =
 181        __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
 182#endif
 183
 184static 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
 199static struct attribute_group part_attr_group = {
 200        .attrs = part_attrs,
 201};
 202
 203static 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
 211static 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
 219struct device_type part_type = {
 220        .name           = "partition",
 221        .groups         = part_attr_groups,
 222        .release        = part_release,
 223};
 224
 225static 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
 235void __delete_partition(struct hd_struct *part)
 236{
 237        call_rcu(&part->rcu_head, delete_partition_rcu_cb);
 238}
 239
 240void 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
 261static ssize_t whole_disk_show(struct device *dev,
 262                               struct device_attribute *attr, char *buf)
 263{
 264        return 0;
 265}
 266static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
 267                   whole_disk_show, NULL);
 268
 269struct 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
 362out_free_info:
 363        free_part_info(p);
 364out_free_stats:
 365        free_part_stats(p);
 366out_free:
 367        kfree(p);
 368        return ERR_PTR(err);
 369out_del:
 370        kobject_put(p->holder_dir);
 371        device_del(pdev);
 372out_put:
 373        put_device(pdev);
 374        blk_free_devt(devt);
 375        return ERR_PTR(err);
 376}
 377
 378static 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
 394static 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
 414int 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;
 419rescan:
 420        if (state && !IS_ERR(state)) {
 421                kfree(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        kfree(state);
 529        return 0;
 530}
 531
 532int 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
 552unsigned 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);
 564fail:
 565                page_cache_release(page);
 566        }
 567        p->v = NULL;
 568        return NULL;
 569}
 570
 571EXPORT_SYMBOL(read_dev_sector);
 572
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