LXR linux/block/ioctl.c

   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 <linux/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                        /* check if partition is aligned to blocksize */
  49                        if (p.start & (bdev_logical_block_size(bdev) - 1))
  50                                return -EINVAL;
  51
  52                        mutex_lock(&bdev->bd_mutex);
  53
  54                        /* overlap? */
  55                        disk_part_iter_init(&piter, disk,
  56                                            DISK_PITER_INCL_EMPTY);
  57                        while ((part = disk_part_iter_next(&piter))) {
  58                                if (!(start + length <= part->start_sect ||
  59                                      start >= part->start_sect + part->nr_sects)) {
  60                                        disk_part_iter_exit(&piter);
  61                                        mutex_unlock(&bdev->bd_mutex);
  62                                        return -EBUSY;
  63                                }
  64                        }
  65                        disk_part_iter_exit(&piter);
  66
  67                        /* all seems OK */
  68                        part = add_partition(disk, partno, start, length,
  69                                             ADDPART_FLAG_NONE, NULL);
  70                        mutex_unlock(&bdev->bd_mutex);
  71                        return PTR_ERR_OR_ZERO(part);
  72                case BLKPG_DEL_PARTITION:
  73                        part = disk_get_part(disk, partno);
  74                        if (!part)
  75                                return -ENXIO;
  76
  77                        bdevp = bdget(part_devt(part));
  78                        disk_put_part(part);
  79                        if (!bdevp)
  80                                return -ENOMEM;
  81
  82                        mutex_lock(&bdevp->bd_mutex);
  83                        if (bdevp->bd_openers) {
  84                                mutex_unlock(&bdevp->bd_mutex);
  85                                bdput(bdevp);
  86                                return -EBUSY;
  87                        }
  88                        /* all seems OK */
  89                        fsync_bdev(bdevp);
  90                        invalidate_bdev(bdevp);
  91
  92                        mutex_lock_nested(&bdev->bd_mutex, 1);
  93                        delete_partition(disk, partno);
  94                        mutex_unlock(&bdev->bd_mutex);
  95                        mutex_unlock(&bdevp->bd_mutex);
  96                        bdput(bdevp);
  97
  98                        return 0;
  99                case BLKPG_RESIZE_PARTITION:
 100                        start = p.start >> 9;
 101                        /* new length of partition in bytes */
 102                        length = p.length >> 9;
 103                        /* check for fit in a hd_struct */
 104                        if (sizeof(sector_t) == sizeof(long) &&
 105                            sizeof(long long) > sizeof(long)) {
 106                                long pstart = start, plength = length;
 107                                if (pstart != start || plength != length
 108                                    || pstart < 0 || plength < 0)
 109                                        return -EINVAL;
 110                        }
 111                        part = disk_get_part(disk, partno);
 112                        if (!part)
 113                                return -ENXIO;
 114                        bdevp = bdget(part_devt(part));
 115                        if (!bdevp) {
 116                                disk_put_part(part);
 117                                return -ENOMEM;
 118                        }
 119                        mutex_lock(&bdevp->bd_mutex);
 120                        mutex_lock_nested(&bdev->bd_mutex, 1);
 121                        if (start != part->start_sect) {
 122                                mutex_unlock(&bdevp->bd_mutex);
 123                                mutex_unlock(&bdev->bd_mutex);
 124                                bdput(bdevp);
 125                                disk_put_part(part);
 126                                return -EINVAL;
 127                        }
 128                        /* overlap? */
 129                        disk_part_iter_init(&piter, disk,
 130                                            DISK_PITER_INCL_EMPTY);
 131                        while ((lpart = disk_part_iter_next(&piter))) {
 132                                if (lpart->partno != partno &&
 133                                   !(start + length <= lpart->start_sect ||
 134                                   start >= lpart->start_sect + lpart->nr_sects)
 135                                   ) {
 136                                        disk_part_iter_exit(&piter);
 137                                        mutex_unlock(&bdevp->bd_mutex);
 138                                        mutex_unlock(&bdev->bd_mutex);
 139                                        bdput(bdevp);
 140                                        disk_put_part(part);
 141                                        return -EBUSY;
 142                                }
 143                        }
 144                        disk_part_iter_exit(&piter);
 145                        part_nr_sects_write(part, (sector_t)length);
 146                        i_size_write(bdevp->bd_inode, p.length);
 147                        mutex_unlock(&bdevp->bd_mutex);
 148                        mutex_unlock(&bdev->bd_mutex);
 149                        bdput(bdevp);
 150                        disk_put_part(part);
 151                        return 0;
 152                default:
 153                        return -EINVAL;
 154        }
 155}
 156
 157/*
 158 * This is an exported API for the block driver, and will not
 159 * acquire bd_mutex. This API should be used in case that
 160 * caller has held bd_mutex already.
 161 */
 162int __blkdev_reread_part(struct block_device *bdev)
 163{
 164        struct gendisk *disk = bdev->bd_disk;
 165
 166        if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
 167                return -EINVAL;
 168        if (!capable(CAP_SYS_ADMIN))
 169                return -EACCES;
 170
 171        lockdep_assert_held(&bdev->bd_mutex);
 172
 173        return rescan_partitions(disk, bdev);
 174}
 175EXPORT_SYMBOL(__blkdev_reread_part);
 176
 177/*
 178 * This is an exported API for the block driver, and will
 179 * try to acquire bd_mutex. If bd_mutex has been held already
 180 * in current context, please call __blkdev_reread_part().
 181 *
 182 * Make sure the held locks in current context aren't required
 183 * in open()/close() handler and I/O path for avoiding ABBA deadlock:
 184 * - bd_mutex is held before calling block driver's open/close
 185 *   handler
 186 * - reading partition table may submit I/O to the block device
 187 */
 188int blkdev_reread_part(struct block_device *bdev)
 189{
 190        int res;
 191
 192        mutex_lock(&bdev->bd_mutex);
 193        res = __blkdev_reread_part(bdev);
 194        mutex_unlock(&bdev->bd_mutex);
 195
 196        return res;
 197}
 198EXPORT_SYMBOL(blkdev_reread_part);
 199
 200static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
 201                unsigned long arg, unsigned long flags)
 202{
 203        uint64_t range[2];
 204        uint64_t start, len;
 205        struct request_queue *q = bdev_get_queue(bdev);
 206        struct address_space *mapping = bdev->bd_inode->i_mapping;
 207
 208
 209        if (!(mode & FMODE_WRITE))
 210                return -EBADF;
 211
 212        if (!blk_queue_discard(q))
 213                return -EOPNOTSUPP;
 214
 215        if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 216                return -EFAULT;
 217
 218        start = range[0];
 219        len = range[1];
 220
 221        if (start & 511)
 222                return -EINVAL;
 223        if (len & 511)
 224                return -EINVAL;
 225
 226        if (start + len > i_size_read(bdev->bd_inode))
 227                return -EINVAL;
 228        truncate_inode_pages_range(mapping, start, start + len - 1);
 229        return blkdev_issue_discard(bdev, start >> 9, len >> 9,
 230                                    GFP_KERNEL, flags);
 231}
 232
 233static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode,
 234                unsigned long arg)
 235{
 236        uint64_t range[2];
 237        struct address_space *mapping;
 238        uint64_t start, end, len;
 239
 240        if (!(mode & FMODE_WRITE))
 241                return -EBADF;
 242
 243        if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 244                return -EFAULT;
 245
 246        start = range[0];
 247        len = range[1];
 248        end = start + len - 1;
 249
 250        if (start & 511)
 251                return -EINVAL;
 252        if (len & 511)
 253                return -EINVAL;
 254        if (end >= (uint64_t)i_size_read(bdev->bd_inode))
 255                return -EINVAL;
 256        if (end < start)
 257                return -EINVAL;
 258
 259        /* Invalidate the page cache, including dirty pages */
 260        mapping = bdev->bd_inode->i_mapping;
 261        truncate_inode_pages_range(mapping, start, end);
 262
 263        return blkdev_issue_zeroout(bdev, start >> 9, len >> 9, GFP_KERNEL,
 264                        BLKDEV_ZERO_NOUNMAP);
 265}
 266
 267static int put_ushort(unsigned long arg, unsigned short val)
 268{
 269        return put_user(val, (unsigned short __user *)arg);
 270}
 271
 272static int put_int(unsigned long arg, int val)
 273{
 274        return put_user(val, (int __user *)arg);
 275}
 276
 277static int put_uint(unsigned long arg, unsigned int val)
 278{
 279        return put_user(val, (unsigned int __user *)arg);
 280}
 281
 282static int put_long(unsigned long arg, long val)
 283{
 284        return put_user(val, (long __user *)arg);
 285}
 286
 287static int put_ulong(unsigned long arg, unsigned long val)
 288{
 289        return put_user(val, (unsigned long __user *)arg);
 290}
 291
 292static int put_u64(unsigned long arg, u64 val)
 293{
 294        return put_user(val, (u64 __user *)arg);
 295}
 296
 297int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 298                        unsigned cmd, unsigned long arg)
 299{
 300        struct gendisk *disk = bdev->bd_disk;
 301
 302        if (disk->fops->ioctl)
 303                return disk->fops->ioctl(bdev, mode, cmd, arg);
 304
 305        return -ENOTTY;
 306}
 307/*
 308 * For the record: _GPL here is only because somebody decided to slap it
 309 * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 310 * at all and could be open-coded without any exports by anybody who cares.
 311 */
 312EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 313
 314static int blkdev_pr_register(struct block_device *bdev,
 315                struct pr_registration __user *arg)
 316{
 317        const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 318        struct pr_registration reg;
 319
 320        if (!capable(CAP_SYS_ADMIN))
 321                return -EPERM;
 322        if (!ops || !ops->pr_register)
 323                return -EOPNOTSUPP;
 324        if (copy_from_user(&reg, arg, sizeof(reg)))
 325                return -EFAULT;
 326
 327        if (reg.flags & ~PR_FL_IGNORE_KEY)
 328                return -EOPNOTSUPP;
 329        return ops->pr_register(bdev, reg.old_key, reg.new_key, reg.flags);
 330}
 331
 332static int blkdev_pr_reserve(struct block_device *bdev,
 333                struct pr_reservation __user *arg)
 334{
 335        const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 336        struct pr_reservation rsv;
 337
 338        if (!capable(CAP_SYS_ADMIN))
 339                return -EPERM;
 340        if (!ops || !ops->pr_reserve)
 341                return -EOPNOTSUPP;
 342        if (copy_from_user(&rsv, arg, sizeof(rsv)))
 343                return -EFAULT;
 344
 345        if (rsv.flags & ~PR_FL_IGNORE_KEY)
 346                return -EOPNOTSUPP;
 347        return ops->pr_reserve(bdev, rsv.key, rsv.type, rsv.flags);
 348}
 349
 350static int blkdev_pr_release(struct block_device *bdev,
 351                struct pr_reservation __user *arg)
 352{
 353        const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 354        struct pr_reservation rsv;
 355
 356        if (!capable(CAP_SYS_ADMIN))
 357                return -EPERM;
 358        if (!ops || !ops->pr_release)
 359                return -EOPNOTSUPP;
 360        if (copy_from_user(&rsv, arg, sizeof(rsv)))
 361                return -EFAULT;
 362
 363        if (rsv.flags)
 364                return -EOPNOTSUPP;
 365        return ops->pr_release(bdev, rsv.key, rsv.type);
 366}
 367
 368static int blkdev_pr_preempt(struct block_device *bdev,
 369                struct pr_preempt __user *arg, bool abort)
 370{
 371        const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 372        struct pr_preempt p;
 373
 374        if (!capable(CAP_SYS_ADMIN))
 375                return -EPERM;
 376        if (!ops || !ops->pr_preempt)
 377                return -EOPNOTSUPP;
 378        if (copy_from_user(&p, arg, sizeof(p)))
 379                return -EFAULT;
 380
 381        if (p.flags)
 382                return -EOPNOTSUPP;
 383        return ops->pr_preempt(bdev, p.old_key, p.new_key, p.type, abort);
 384}
 385
 386static int blkdev_pr_clear(struct block_device *bdev,
 387                struct pr_clear __user *arg)
 388{
 389        const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 390        struct pr_clear c;
 391
 392        if (!capable(CAP_SYS_ADMIN))
 393                return -EPERM;
 394        if (!ops || !ops->pr_clear)
 395                return -EOPNOTSUPP;
 396        if (copy_from_user(&c, arg, sizeof(c)))
 397                return -EFAULT;
 398
 399        if (c.flags)
 400                return -EOPNOTSUPP;
 401        return ops->pr_clear(bdev, c.key);
 402}
 403
 404/*
 405 * Is it an unrecognized ioctl? The correct returns are either
 406 * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
 407 * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
 408 * code before returning.
 409 *
 410 * Confused drivers sometimes return EINVAL, which is wrong. It
 411 * means "I understood the ioctl command, but the parameters to
 412 * it were wrong".
 413 *
 414 * We should aim to just fix the broken drivers, the EINVAL case
 415 * should go away.
 416 */
 417static inline int is_unrecognized_ioctl(int ret)
 418{
 419        return  ret == -EINVAL ||
 420                ret == -ENOTTY ||
 421                ret == -ENOIOCTLCMD;
 422}
 423
 424static int blkdev_flushbuf(struct block_device *bdev, fmode_t mode,
 425                unsigned cmd, unsigned long arg)
 426{
 427        int ret;
 428
 429        if (!capable(CAP_SYS_ADMIN))
 430                return -EACCES;
 431
 432        ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 433        if (!is_unrecognized_ioctl(ret))
 434                return ret;
 435
 436        fsync_bdev(bdev);
 437        invalidate_bdev(bdev);
 438        return 0;
 439}
 440
 441static int blkdev_roset(struct block_device *bdev, fmode_t mode,
 442                unsigned cmd, unsigned long arg)
 443{
 444        int ret, n;
 445
 446        if (!capable(CAP_SYS_ADMIN))
 447                return -EACCES;
 448
 449        ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 450        if (!is_unrecognized_ioctl(ret))
 451                return ret;
 452        if (get_user(n, (int __user *)arg))
 453                return -EFAULT;
 454        set_device_ro(bdev, n);
 455        return 0;
 456}
 457
 458static int blkdev_getgeo(struct block_device *bdev,
 459                struct hd_geometry __user *argp)
 460{
 461        struct gendisk *disk = bdev->bd_disk;
 462        struct hd_geometry geo;
 463        int ret;
 464
 465        if (!argp)
 466                return -EINVAL;
 467        if (!disk->fops->getgeo)
 468                return -ENOTTY;
 469
 470        /*
 471         * We need to set the startsect first, the driver may
 472         * want to override it.
 473         */
 474        memset(&geo, 0, sizeof(geo));
 475        geo.start = get_start_sect(bdev);
 476        ret = disk->fops->getgeo(bdev, &geo);
 477        if (ret)
 478                return ret;
 479        if (copy_to_user(argp, &geo, sizeof(geo)))
 480                return -EFAULT;
 481        return 0;
 482}
 483
 484/* set the logical block size */
 485static int blkdev_bszset(struct block_device *bdev, fmode_t mode,
 486                int __user *argp)
 487{
 488        int ret, n;
 489
 490        if (!capable(CAP_SYS_ADMIN))
 491                return -EACCES;
 492        if (!argp)
 493                return -EINVAL;
 494        if (get_user(n, argp))
 495                return -EFAULT;
 496
 497        if (!(mode & FMODE_EXCL)) {
 498                bdgrab(bdev);
 499                if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
 500                        return -EBUSY;
 501        }
 502
 503        ret = set_blocksize(bdev, n);
 504        if (!(mode & FMODE_EXCL))
 505                blkdev_put(bdev, mode | FMODE_EXCL);
 506        return ret;
 507}
 508
 509/*
 510 * always keep this in sync with compat_blkdev_ioctl()
 511 */
 512int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 513                        unsigned long arg)
 514{
 515        void __user *argp = (void __user *)arg;
 516        loff_t size;
 517        unsigned int max_sectors;
 518
 519        switch (cmd) {
 520        case BLKFLSBUF:
 521                return blkdev_flushbuf(bdev, mode, cmd, arg);
 522        case BLKROSET:
 523                return blkdev_roset(bdev, mode, cmd, arg);
 524        case BLKDISCARD:
 525                return blk_ioctl_discard(bdev, mode, arg, 0);
 526        case BLKSECDISCARD:
 527                return blk_ioctl_discard(bdev, mode, arg,
 528                                BLKDEV_DISCARD_SECURE);
 529        case BLKZEROOUT:
 530                return blk_ioctl_zeroout(bdev, mode, arg);
 531        case BLKREPORTZONE:
 532                return blkdev_report_zones_ioctl(bdev, mode, cmd, arg);
 533        case BLKRESETZONE:
 534                return blkdev_reset_zones_ioctl(bdev, mode, cmd, arg);
 535        case HDIO_GETGEO:
 536                return blkdev_getgeo(bdev, argp);
 537        case BLKRAGET:
 538        case BLKFRAGET:
 539                if (!arg)
 540                        return -EINVAL;
 541                return put_long(arg, (bdev->bd_bdi->ra_pages*PAGE_SIZE) / 512);
 542        case BLKROGET:
 543                return put_int(arg, bdev_read_only(bdev) != 0);
 544        case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
 545                return put_int(arg, block_size(bdev));
 546        case BLKSSZGET: /* get block device logical block size */
 547                return put_int(arg, bdev_logical_block_size(bdev));
 548        case BLKPBSZGET: /* get block device physical block size */
 549                return put_uint(arg, bdev_physical_block_size(bdev));
 550        case BLKIOMIN:
 551                return put_uint(arg, bdev_io_min(bdev));
 552        case BLKIOOPT:
 553                return put_uint(arg, bdev_io_opt(bdev));
 554        case BLKALIGNOFF:
 555                return put_int(arg, bdev_alignment_offset(bdev));
 556        case BLKDISCARDZEROES:
 557                return put_uint(arg, 0);
 558        case BLKSECTGET:
 559                max_sectors = min_t(unsigned int, USHRT_MAX,
 560                                    queue_max_sectors(bdev_get_queue(bdev)));
 561                return put_ushort(arg, max_sectors);
 562        case BLKROTATIONAL:
 563                return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
 564        case BLKRASET:
 565        case BLKFRASET:
 566                if(!capable(CAP_SYS_ADMIN))
 567                        return -EACCES;
 568                bdev->bd_bdi->ra_pages = (arg * 512) / PAGE_SIZE;
 569                return 0;
 570        case BLKBSZSET:
 571                return blkdev_bszset(bdev, mode, argp);
 572        case BLKPG:
 573                return blkpg_ioctl(bdev, argp);
 574        case BLKRRPART:
 575                return blkdev_reread_part(bdev);
 576        case BLKGETSIZE:
 577                size = i_size_read(bdev->bd_inode);
 578                if ((size >> 9) > ~0UL)
 579                        return -EFBIG;
 580                return put_ulong(arg, size >> 9);
 581        case BLKGETSIZE64:
 582                return put_u64(arg, i_size_read(bdev->bd_inode));
 583        case BLKTRACESTART:
 584        case BLKTRACESTOP:
 585        case BLKTRACESETUP:
 586        case BLKTRACETEARDOWN:
 587                return blk_trace_ioctl(bdev, cmd, argp);
 588        case IOC_PR_REGISTER:
 589                return blkdev_pr_register(bdev, argp);
 590        case IOC_PR_RESERVE:
 591                return blkdev_pr_reserve(bdev, argp);
 592        case IOC_PR_RELEASE:
 593                return blkdev_pr_release(bdev, argp);
 594        case IOC_PR_PREEMPT:
 595                return blkdev_pr_preempt(bdev, argp, false);
 596        case IOC_PR_PREEMPT_ABORT:
 597                return blkdev_pr_preempt(bdev, argp, true);
 598        case IOC_PR_CLEAR:
 599                return blkdev_pr_clear(bdev, argp);
 600        default:
 601                return __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 602        }
 603}
 604EXPORT_SYMBOL_GPL(blkdev_ioctl);
 605