linux/block/ioctl.c
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   1#include <linux/capability.h>
   2#include <linux/blkdev.h>
   3#include <linux/export.h>
   4#include <linux/gfp.h>
   5#include <linux/blkpg.h>
   6#include <linux/hdreg.h>
   7#include <linux/backing-dev.h>
   8#include <linux/fs.h>
   9#include <linux/blktrace_api.h>
  10#include <linux/pr.h>
  11#include <asm/uaccess.h>
  12
  13static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
  14{
  15        struct block_device *bdevp;
  16        struct gendisk *disk;
  17        struct hd_struct *part, *lpart;
  18        struct blkpg_ioctl_arg a;
  19        struct blkpg_partition p;
  20        struct disk_part_iter piter;
  21        long long start, length;
  22        int partno;
  23
  24        if (!capable(CAP_SYS_ADMIN))
  25                return -EACCES;
  26        if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
  27                return -EFAULT;
  28        if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
  29                return -EFAULT;
  30        disk = bdev->bd_disk;
  31        if (bdev != bdev->bd_contains)
  32                return -EINVAL;
  33        partno = p.pno;
  34        if (partno <= 0)
  35                return -EINVAL;
  36        switch (a.op) {
  37                case BLKPG_ADD_PARTITION:
  38                        start = p.start >> 9;
  39                        length = p.length >> 9;
  40                        /* check for fit in a hd_struct */
  41                        if (sizeof(sector_t) == sizeof(long) &&
  42                            sizeof(long long) > sizeof(long)) {
  43                                long pstart = start, plength = length;
  44                                if (pstart != start || plength != length
  45                                    || pstart < 0 || plength < 0 || partno > 65535)
  46                                        return -EINVAL;
  47                        }
  48
  49                        mutex_lock(&bdev->bd_mutex);
  50
  51                        /* overlap? */
  52                        disk_part_iter_init(&piter, disk,
  53                                            DISK_PITER_INCL_EMPTY);
  54                        while ((part = disk_part_iter_next(&piter))) {
  55                                if (!(start + length <= part->start_sect ||
  56                                      start >= part->start_sect + part->nr_sects)) {
  57                                        disk_part_iter_exit(&piter);
  58                                        mutex_unlock(&bdev->bd_mutex);
  59                                        return -EBUSY;
  60                                }
  61                        }
  62                        disk_part_iter_exit(&piter);
  63
  64                        /* all seems OK */
  65                        part = add_partition(disk, partno, start, length,
  66                                             ADDPART_FLAG_NONE, NULL);
  67                        mutex_unlock(&bdev->bd_mutex);
  68                        return PTR_ERR_OR_ZERO(part);
  69                case BLKPG_DEL_PARTITION:
  70                        part = disk_get_part(disk, partno);
  71                        if (!part)
  72                                return -ENXIO;
  73
  74                        bdevp = bdget(part_devt(part));
  75                        disk_put_part(part);
  76                        if (!bdevp)
  77                                return -ENOMEM;
  78
  79                        mutex_lock(&bdevp->bd_mutex);
  80                        if (bdevp->bd_openers) {
  81                                mutex_unlock(&bdevp->bd_mutex);
  82                                bdput(bdevp);
  83                                return -EBUSY;
  84                        }
  85                        /* all seems OK */
  86                        fsync_bdev(bdevp);
  87                        invalidate_bdev(bdevp);
  88
  89                        mutex_lock_nested(&bdev->bd_mutex, 1);
  90                        delete_partition(disk, partno);
  91                        mutex_unlock(&bdev->bd_mutex);
  92                        mutex_unlock(&bdevp->bd_mutex);
  93                        bdput(bdevp);
  94
  95                        return 0;
  96                case BLKPG_RESIZE_PARTITION:
  97                        start = p.start >> 9;
  98                        /* new length of partition in bytes */
  99                        length = p.length >> 9;
 100                        /* check for fit in a hd_struct */
 101                        if (sizeof(sector_t) == sizeof(long) &&
 102                            sizeof(long long) > sizeof(long)) {
 103                                long pstart = start, plength = length;
 104                                if (pstart != start || plength != length
 105                                    || pstart < 0 || plength < 0)
 106                                        return -EINVAL;
 107                        }
 108                        part = disk_get_part(disk, partno);
 109                        if (!part)
 110                                return -ENXIO;
 111                        bdevp = bdget(part_devt(part));
 112                        if (!bdevp) {
 113                                disk_put_part(part);
 114                                return -ENOMEM;
 115                        }
 116                        mutex_lock(&bdevp->bd_mutex);
 117                        mutex_lock_nested(&bdev->bd_mutex, 1);
 118                        if (start != part->start_sect) {
 119                                mutex_unlock(&bdevp->bd_mutex);
 120                                mutex_unlock(&bdev->bd_mutex);
 121                                bdput(bdevp);
 122                                disk_put_part(part);
 123                                return -EINVAL;
 124                        }
 125                        /* overlap? */
 126                        disk_part_iter_init(&piter, disk,
 127                                            DISK_PITER_INCL_EMPTY);
 128                        while ((lpart = disk_part_iter_next(&piter))) {
 129                                if (lpart->partno != partno &&
 130                                   !(start + length <= lpart->start_sect ||
 131                                   start >= lpart->start_sect + lpart->nr_sects)
 132                                   ) {
 133                                        disk_part_iter_exit(&piter);
 134                                        mutex_unlock(&bdevp->bd_mutex);
 135                                        mutex_unlock(&bdev->bd_mutex);
 136                                        bdput(bdevp);
 137                                        disk_put_part(part);
 138                                        return -EBUSY;
 139                                }
 140                        }
 141                        disk_part_iter_exit(&piter);
 142                        part_nr_sects_write(part, (sector_t)length);
 143                        i_size_write(bdevp->bd_inode, p.length);
 144                        mutex_unlock(&bdevp->bd_mutex);
 145                        mutex_unlock(&bdev->bd_mutex);
 146                        bdput(bdevp);
 147                        disk_put_part(part);
 148                        return 0;
 149                default:
 150                        return -EINVAL;
 151        }
 152}
 153
 154/*
 155 * This is an exported API for the block driver, and will not
 156 * acquire bd_mutex. This API should be used in case that
 157 * caller has held bd_mutex already.
 158 */
 159int __blkdev_reread_part(struct block_device *bdev)
 160{
 161        struct gendisk *disk = bdev->bd_disk;
 162
 163        if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
 164                return -EINVAL;
 165        if (!capable(CAP_SYS_ADMIN))
 166                return -EACCES;
 167
 168        lockdep_assert_held(&bdev->bd_mutex);
 169
 170        return rescan_partitions(disk, bdev);
 171}
 172EXPORT_SYMBOL(__blkdev_reread_part);
 173
 174/*
 175 * This is an exported API for the block driver, and will
 176 * try to acquire bd_mutex. If bd_mutex has been held already
 177 * in current context, please call __blkdev_reread_part().
 178 *
 179 * Make sure the held locks in current context aren't required
 180 * in open()/close() handler and I/O path for avoiding ABBA deadlock:
 181 * - bd_mutex is held before calling block driver's open/close
 182 *   handler
 183 * - reading partition table may submit I/O to the block device
 184 */
 185int blkdev_reread_part(struct block_device *bdev)
 186{
 187        int res;
 188
 189        mutex_lock(&bdev->bd_mutex);
 190        res = __blkdev_reread_part(bdev);
 191        mutex_unlock(&bdev->bd_mutex);
 192
 193        return res;
 194}
 195EXPORT_SYMBOL(blkdev_reread_part);
 196
 197static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
 198                unsigned long arg, unsigned long flags)
 199{
 200        uint64_t range[2];
 201        uint64_t start, len;
 202
 203        if (!(mode & FMODE_WRITE))
 204                return -EBADF;
 205
 206        if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 207                return -EFAULT;
 208
 209        start = range[0];
 210        len = range[1];
 211
 212        if (start & 511)
 213                return -EINVAL;
 214        if (len & 511)
 215                return -EINVAL;
 216        start >>= 9;
 217        len >>= 9;
 218
 219        if (start + len > (i_size_read(bdev->bd_inode) >> 9))
 220                return -EINVAL;
 221        return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
 222}
 223
 224static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode,
 225                unsigned long arg)
 226{
 227        uint64_t range[2];
 228        struct address_space *mapping;
 229        uint64_t start, end, len;
 230
 231        if (!(mode & FMODE_WRITE))
 232                return -EBADF;
 233
 234        if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 235                return -EFAULT;
 236
 237        start = range[0];
 238        len = range[1];
 239        end = start + len - 1;
 240
 241        if (start & 511)
 242                return -EINVAL;
 243        if (len & 511)
 244                return -EINVAL;
 245        if (end >= (uint64_t)i_size_read(bdev->bd_inode))
 246                return -EINVAL;
 247        if (end < start)
 248                return -EINVAL;
 249
 250        /* Invalidate the page cache, including dirty pages */
 251        mapping = bdev->bd_inode->i_mapping;
 252        truncate_inode_pages_range(mapping, start, end);
 253
 254        return blkdev_issue_zeroout(bdev, start >> 9, len >> 9, GFP_KERNEL,
 255                                    false);
 256}
 257
 258static int put_ushort(unsigned long arg, unsigned short val)
 259{
 260        return put_user(val, (unsigned short __user *)arg);
 261}
 262
 263static int put_int(unsigned long arg, int val)
 264{
 265        return put_user(val, (int __user *)arg);
 266}
 267
 268static int put_uint(unsigned long arg, unsigned int val)
 269{
 270        return put_user(val, (unsigned int __user *)arg);
 271}
 272
 273static int put_long(unsigned long arg, long val)
 274{
 275        return put_user(val, (long __user *)arg);
 276}
 277
 278static int put_ulong(unsigned long arg, unsigned long val)
 279{
 280        return put_user(val, (unsigned long __user *)arg);
 281}
 282
 283static int put_u64(unsigned long arg, u64 val)
 284{
 285        return put_user(val, (u64 __user *)arg);
 286}
 287
 288int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 289                        unsigned cmd, unsigned long arg)
 290{
 291        struct gendisk *disk = bdev->bd_disk;
 292
 293        if (disk->fops->ioctl)
 294                return disk->fops->ioctl(bdev, mode, cmd, arg);
 295
 296        return -ENOTTY;
 297}
 298/*
 299 * For the record: _GPL here is only because somebody decided to slap it
 300 * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 301 * at all and could be open-coded without any exports by anybody who cares.
 302 */
 303EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 304
 305static int blkdev_pr_register(struct block_device *bdev,
 306                struct pr_registration __user *arg)
 307{
 308        const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 309        struct pr_registration reg;
 310
 311        if (!capable(CAP_SYS_ADMIN))
 312                return -EPERM;
 313        if (!ops || !ops->pr_register)
 314                return -EOPNOTSUPP;
 315        if (copy_from_user(&reg, arg, sizeof(reg)))
 316                return -EFAULT;
 317
 318        if (reg.flags & ~PR_FL_IGNORE_KEY)
 319                return -EOPNOTSUPP;
 320        return ops->pr_register(bdev, reg.old_key, reg.new_key, reg.flags);
 321}
 322
 323static int blkdev_pr_reserve(struct block_device *bdev,
 324                struct pr_reservation __user *arg)
 325{
 326        const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 327        struct pr_reservation rsv;
 328
 329        if (!capable(CAP_SYS_ADMIN))
 330                return -EPERM;
 331        if (!ops || !ops->pr_reserve)
 332                return -EOPNOTSUPP;
 333        if (copy_from_user(&rsv, arg, sizeof(rsv)))
 334                return -EFAULT;
 335
 336        if (rsv.flags & ~PR_FL_IGNORE_KEY)
 337                return -EOPNOTSUPP;
 338        return ops->pr_reserve(bdev, rsv.key, rsv.type, rsv.flags);
 339}
 340
 341static int blkdev_pr_release(struct block_device *bdev,
 342                struct pr_reservation __user *arg)
 343{
 344        const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 345        struct pr_reservation rsv;
 346
 347        if (!capable(CAP_SYS_ADMIN))
 348                return -EPERM;
 349        if (!ops || !ops->pr_release)
 350                return -EOPNOTSUPP;
 351        if (copy_from_user(&rsv, arg, sizeof(rsv)))
 352                return -EFAULT;
 353
 354        if (rsv.flags)
 355                return -EOPNOTSUPP;
 356        return ops->pr_release(bdev, rsv.key, rsv.type);
 357}
 358
 359static int blkdev_pr_preempt(struct block_device *bdev,
 360                struct pr_preempt __user *arg, bool abort)
 361{
 362        const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 363        struct pr_preempt p;
 364
 365        if (!capable(CAP_SYS_ADMIN))
 366                return -EPERM;
 367        if (!ops || !ops->pr_preempt)
 368                return -EOPNOTSUPP;
 369        if (copy_from_user(&p, arg, sizeof(p)))
 370                return -EFAULT;
 371
 372        if (p.flags)
 373                return -EOPNOTSUPP;
 374        return ops->pr_preempt(bdev, p.old_key, p.new_key, p.type, abort);
 375}
 376
 377static int blkdev_pr_clear(struct block_device *bdev,
 378                struct pr_clear __user *arg)
 379{
 380        const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 381        struct pr_clear c;
 382
 383        if (!capable(CAP_SYS_ADMIN))
 384                return -EPERM;
 385        if (!ops || !ops->pr_clear)
 386                return -EOPNOTSUPP;
 387        if (copy_from_user(&c, arg, sizeof(c)))
 388                return -EFAULT;
 389
 390        if (c.flags)
 391                return -EOPNOTSUPP;
 392        return ops->pr_clear(bdev, c.key);
 393}
 394
 395/*
 396 * Is it an unrecognized ioctl? The correct returns are either
 397 * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
 398 * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
 399 * code before returning.
 400 *
 401 * Confused drivers sometimes return EINVAL, which is wrong. It
 402 * means "I understood the ioctl command, but the parameters to
 403 * it were wrong".
 404 *
 405 * We should aim to just fix the broken drivers, the EINVAL case
 406 * should go away.
 407 */
 408static inline int is_unrecognized_ioctl(int ret)
 409{
 410        return  ret == -EINVAL ||
 411                ret == -ENOTTY ||
 412                ret == -ENOIOCTLCMD;
 413}
 414
 415static int blkdev_flushbuf(struct block_device *bdev, fmode_t mode,
 416                unsigned cmd, unsigned long arg)
 417{
 418        int ret;
 419
 420        if (!capable(CAP_SYS_ADMIN))
 421                return -EACCES;
 422
 423        ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 424        if (!is_unrecognized_ioctl(ret))
 425                return ret;
 426
 427        fsync_bdev(bdev);
 428        invalidate_bdev(bdev);
 429        return 0;
 430}
 431
 432static int blkdev_roset(struct block_device *bdev, fmode_t mode,
 433                unsigned cmd, unsigned long arg)
 434{
 435        int ret, n;
 436
 437        ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 438        if (!is_unrecognized_ioctl(ret))
 439                return ret;
 440        if (!capable(CAP_SYS_ADMIN))
 441                return -EACCES;
 442        if (get_user(n, (int __user *)arg))
 443                return -EFAULT;
 444        set_device_ro(bdev, n);
 445        return 0;
 446}
 447
 448static int blkdev_getgeo(struct block_device *bdev,
 449                struct hd_geometry __user *argp)
 450{
 451        struct gendisk *disk = bdev->bd_disk;
 452        struct hd_geometry geo;
 453        int ret;
 454
 455        if (!argp)
 456                return -EINVAL;
 457        if (!disk->fops->getgeo)
 458                return -ENOTTY;
 459
 460        /*
 461         * We need to set the startsect first, the driver may
 462         * want to override it.
 463         */
 464        memset(&geo, 0, sizeof(geo));
 465        geo.start = get_start_sect(bdev);
 466        ret = disk->fops->getgeo(bdev, &geo);
 467        if (ret)
 468                return ret;
 469        if (copy_to_user(argp, &geo, sizeof(geo)))
 470                return -EFAULT;
 471        return 0;
 472}
 473
 474/* set the logical block size */
 475static int blkdev_bszset(struct block_device *bdev, fmode_t mode,
 476                int __user *argp)
 477{
 478        int ret, n;
 479
 480        if (!capable(CAP_SYS_ADMIN))
 481                return -EACCES;
 482        if (!argp)
 483                return -EINVAL;
 484        if (get_user(n, argp))
 485                return -EFAULT;
 486
 487        if (!(mode & FMODE_EXCL)) {
 488                bdgrab(bdev);
 489                if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
 490                        return -EBUSY;
 491        }
 492
 493        ret = set_blocksize(bdev, n);
 494        if (!(mode & FMODE_EXCL))
 495                blkdev_put(bdev, mode | FMODE_EXCL);
 496        return ret;
 497}
 498
 499/*
 500 * always keep this in sync with compat_blkdev_ioctl()
 501 */
 502int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 503                        unsigned long arg)
 504{
 505        struct backing_dev_info *bdi;
 506        void __user *argp = (void __user *)arg;
 507        loff_t size;
 508        unsigned int max_sectors;
 509
 510        switch (cmd) {
 511        case BLKFLSBUF:
 512                return blkdev_flushbuf(bdev, mode, cmd, arg);
 513        case BLKROSET:
 514                return blkdev_roset(bdev, mode, cmd, arg);
 515        case BLKDISCARD:
 516                return blk_ioctl_discard(bdev, mode, arg, 0);
 517        case BLKSECDISCARD:
 518                return blk_ioctl_discard(bdev, mode, arg,
 519                                BLKDEV_DISCARD_SECURE);
 520        case BLKZEROOUT:
 521                return blk_ioctl_zeroout(bdev, mode, arg);
 522        case HDIO_GETGEO:
 523                return blkdev_getgeo(bdev, argp);
 524        case BLKRAGET:
 525        case BLKFRAGET:
 526                if (!arg)
 527                        return -EINVAL;
 528                bdi = blk_get_backing_dev_info(bdev);
 529                return put_long(arg, (bdi->ra_pages * PAGE_SIZE) / 512);
 530        case BLKROGET:
 531                return put_int(arg, bdev_read_only(bdev) != 0);
 532        case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
 533                return put_int(arg, block_size(bdev));
 534        case BLKSSZGET: /* get block device logical block size */
 535                return put_int(arg, bdev_logical_block_size(bdev));
 536        case BLKPBSZGET: /* get block device physical block size */
 537                return put_uint(arg, bdev_physical_block_size(bdev));
 538        case BLKIOMIN:
 539                return put_uint(arg, bdev_io_min(bdev));
 540        case BLKIOOPT:
 541                return put_uint(arg, bdev_io_opt(bdev));
 542        case BLKALIGNOFF:
 543                return put_int(arg, bdev_alignment_offset(bdev));
 544        case BLKDISCARDZEROES:
 545                return put_uint(arg, bdev_discard_zeroes_data(bdev));
 546        case BLKSECTGET:
 547                max_sectors = min_t(unsigned int, USHRT_MAX,
 548                                    queue_max_sectors(bdev_get_queue(bdev)));
 549                return put_ushort(arg, max_sectors);
 550        case BLKROTATIONAL:
 551                return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
 552        case BLKRASET:
 553        case BLKFRASET:
 554                if(!capable(CAP_SYS_ADMIN))
 555                        return -EACCES;
 556                bdi = blk_get_backing_dev_info(bdev);
 557                bdi->ra_pages = (arg * 512) / PAGE_SIZE;
 558                return 0;
 559        case BLKBSZSET:
 560                return blkdev_bszset(bdev, mode, argp);
 561        case BLKPG:
 562                return blkpg_ioctl(bdev, argp);
 563        case BLKRRPART:
 564                return blkdev_reread_part(bdev);
 565        case BLKGETSIZE:
 566                size = i_size_read(bdev->bd_inode);
 567                if ((size >> 9) > ~0UL)
 568                        return -EFBIG;
 569                return put_ulong(arg, size >> 9);
 570        case BLKGETSIZE64:
 571                return put_u64(arg, i_size_read(bdev->bd_inode));
 572        case BLKTRACESTART:
 573        case BLKTRACESTOP:
 574        case BLKTRACESETUP:
 575        case BLKTRACETEARDOWN:
 576                return blk_trace_ioctl(bdev, cmd, argp);
 577        case IOC_PR_REGISTER:
 578                return blkdev_pr_register(bdev, argp);
 579        case IOC_PR_RESERVE:
 580                return blkdev_pr_reserve(bdev, argp);
 581        case IOC_PR_RELEASE:
 582                return blkdev_pr_release(bdev, argp);
 583        case IOC_PR_PREEMPT:
 584                return blkdev_pr_preempt(bdev, argp, false);
 585        case IOC_PR_PREEMPT_ABORT:
 586                return blkdev_pr_preempt(bdev, argp, true);
 587        case IOC_PR_CLEAR:
 588                return blkdev_pr_clear(bdev, argp);
 589        default:
 590                return __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 591        }
 592}
 593EXPORT_SYMBOL_GPL(blkdev_ioctl);
 594