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
  13 static 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  */
 162 int __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 }
 175 EXPORT_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  */
 188 int 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 }
 198 EXPORT_SYMBOL(blkdev_reread_part);
 199
 200 static 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
 233 static 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
 267 static int put_ushort(unsigned long arg, unsigned short val)
 268 {
 269         return put_user(val, (unsigned short __user *)arg);
 270 }
 271
 272 static int put_int(unsigned long arg, int val)
 273 {
 274         return put_user(val, (int __user *)arg);
 275 }
 276
 277 static int put_uint(unsigned long arg, unsigned int val)
 278 {
 279         return put_user(val, (unsigned int __user *)arg);
 280 }
 281
 282 static int put_long(unsigned long arg, long val)
 283 {
 284         return put_user(val, (long __user *)arg);
 285 }
 286
 287 static int put_ulong(unsigned long arg, unsigned long val)
 288 {
 289         return put_user(val, (unsigned long __user *)arg);
 290 }
 291
 292 static int put_u64(unsigned long arg, u64 val)
 293 {
 294         return put_user(val, (u64 __user *)arg);
 295 }
 296
 297 int __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  */
 312 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 313
 314 static 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
 332 static 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
 350 static 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
 368 static 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
 386 static 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  */
 417 static inline int is_unrecognized_ioctl(int ret)
 418 {
 419         return  ret == -EINVAL ||
 420                 ret == -ENOTTY ||
 421                 ret == -ENOIOCTLCMD;
 422 }
 423
 424 static 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
 441 static 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
 458 static 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 */
 485 static 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  */
 512 int 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 BLKGETZONESZ:
 536                 return put_uint(arg, bdev_zone_sectors(bdev));
 537         case BLKGETNRZONES:
 538                 return put_uint(arg, blkdev_nr_zones(bdev));
 539         case HDIO_GETGEO:
 540                 return blkdev_getgeo(bdev, argp);
 541         case BLKRAGET:
 542         case BLKFRAGET:
 543                 if (!arg)
 544                         return -EINVAL;
 545                 return put_long(arg, (bdev->bd_bdi->ra_pages*PAGE_SIZE) / 512);
 546         case BLKROGET:
 547                 return put_int(arg, bdev_read_only(bdev) != 0);
 548         case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
 549                 return put_int(arg, block_size(bdev));
 550         case BLKSSZGET: /* get block device logical block size */
 551                 return put_int(arg, bdev_logical_block_size(bdev));
 552         case BLKPBSZGET: /* get block device physical block size */
 553                 return put_uint(arg, bdev_physical_block_size(bdev));
 554         case BLKIOMIN:
 555                 return put_uint(arg, bdev_io_min(bdev));
 556         case BLKIOOPT:
 557                 return put_uint(arg, bdev_io_opt(bdev));
 558         case BLKALIGNOFF:
 559                 return put_int(arg, bdev_alignment_offset(bdev));
 560         case BLKDISCARDZEROES:
 561                 return put_uint(arg, 0);
 562         case BLKSECTGET:
 563                 max_sectors = min_t(unsigned int, USHRT_MAX,
 564                                     queue_max_sectors(bdev_get_queue(bdev)));
 565                 return put_ushort(arg, max_sectors);
 566         case BLKROTATIONAL:
 567                 return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
 568         case BLKRASET:
 569         case BLKFRASET:
 570                 if(!capable(CAP_SYS_ADMIN))
 571                         return -EACCES;
 572                 bdev->bd_bdi->ra_pages = (arg * 512) / PAGE_SIZE;
 573                 return 0;
 574         case BLKBSZSET:
 575                 return blkdev_bszset(bdev, mode, argp);
 576         case BLKPG:
 577                 return blkpg_ioctl(bdev, argp);
 578         case BLKRRPART:
 579                 return blkdev_reread_part(bdev);
 580         case BLKGETSIZE:
 581                 size = i_size_read(bdev->bd_inode);
 582                 if ((size >> 9) > ~0UL)
 583                         return -EFBIG;
 584                 return put_ulong(arg, size >> 9);
 585         case BLKGETSIZE64:
 586                 return put_u64(arg, i_size_read(bdev->bd_inode));
 587         case BLKTRACESTART:
 588         case BLKTRACESTOP:
 589         case BLKTRACESETUP:
 590         case BLKTRACETEARDOWN:
 591                 return blk_trace_ioctl(bdev, cmd, argp);
 592         case IOC_PR_REGISTER:
 593                 return blkdev_pr_register(bdev, argp);
 594         case IOC_PR_RESERVE:
 595                 return blkdev_pr_reserve(bdev, argp);
 596         case IOC_PR_RELEASE:
 597                 return blkdev_pr_release(bdev, argp);
 598         case IOC_PR_PREEMPT:
 599                 return blkdev_pr_preempt(bdev, argp, false);
 600         case IOC_PR_PREEMPT_ABORT:
 601                 return blkdev_pr_preempt(bdev, argp, true);
 602         case IOC_PR_CLEAR:
 603                 return blkdev_pr_clear(bdev, argp);
 604         default:
 605                 return __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 606         }
 607 }
 608 EXPORT_SYMBOL_GPL(blkdev_ioctl);