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/badblocks.h>
   8 #include <linux/backing-dev.h>
   9 #include <linux/fs.h>
  10 #include <linux/blktrace_api.h>
  11 #include <linux/pr.h>
  12 #include <asm/uaccess.h>
  13
  14 static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
  15 {
  16         struct block_device *bdevp;
  17         struct gendisk *disk;
  18         struct hd_struct *part, *lpart;
  19         struct blkpg_ioctl_arg a;
  20         struct blkpg_partition p;
  21         struct disk_part_iter piter;
  22         long long start, length;
  23         int partno;
  24
  25         if (!capable(CAP_SYS_ADMIN))
  26                 return -EACCES;
  27         if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
  28                 return -EFAULT;
  29         if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
  30                 return -EFAULT;
  31         disk = bdev->bd_disk;
  32         if (bdev != bdev->bd_contains)
  33                 return -EINVAL;
  34         partno = p.pno;
  35         if (partno <= 0)
  36                 return -EINVAL;
  37         switch (a.op) {
  38                 case BLKPG_ADD_PARTITION:
  39                         start = p.start >> 9;
  40                         length = p.length >> 9;
  41                         /* check for fit in a hd_struct */
  42                         if (sizeof(sector_t) == sizeof(long) &&
  43                             sizeof(long long) > sizeof(long)) {
  44                                 long pstart = start, plength = length;
  45                                 if (pstart != start || plength != length
  46                                     || pstart < 0 || plength < 0 || partno > 65535)
  47                                         return -EINVAL;
  48                         }
  49
  50                         mutex_lock(&bdev->bd_mutex);
  51
  52                         /* overlap? */
  53                         disk_part_iter_init(&piter, disk,
  54                                             DISK_PITER_INCL_EMPTY);
  55                         while ((part = disk_part_iter_next(&piter))) {
  56                                 if (!(start + length <= part->start_sect ||
  57                                       start >= part->start_sect + part->nr_sects)) {
  58                                         disk_part_iter_exit(&piter);
  59                                         mutex_unlock(&bdev->bd_mutex);
  60                                         return -EBUSY;
  61                                 }
  62                         }
  63                         disk_part_iter_exit(&piter);
  64
  65                         /* all seems OK */
  66                         part = add_partition(disk, partno, start, length,
  67                                              ADDPART_FLAG_NONE, NULL);
  68                         mutex_unlock(&bdev->bd_mutex);
  69                         return PTR_ERR_OR_ZERO(part);
  70                 case BLKPG_DEL_PARTITION:
  71                         part = disk_get_part(disk, partno);
  72                         if (!part)
  73                                 return -ENXIO;
  74
  75                         bdevp = bdget(part_devt(part));
  76                         disk_put_part(part);
  77                         if (!bdevp)
  78                                 return -ENOMEM;
  79
  80                         mutex_lock(&bdevp->bd_mutex);
  81                         if (bdevp->bd_openers) {
  82                                 mutex_unlock(&bdevp->bd_mutex);
  83                                 bdput(bdevp);
  84                                 return -EBUSY;
  85                         }
  86                         /* all seems OK */
  87                         fsync_bdev(bdevp);
  88                         invalidate_bdev(bdevp);
  89
  90                         mutex_lock_nested(&bdev->bd_mutex, 1);
  91                         delete_partition(disk, partno);
  92                         mutex_unlock(&bdev->bd_mutex);
  93                         mutex_unlock(&bdevp->bd_mutex);
  94                         bdput(bdevp);
  95
  96                         return 0;
  97                 case BLKPG_RESIZE_PARTITION:
  98                         start = p.start >> 9;
  99                         /* new length of partition in bytes */
 100                         length = p.length >> 9;
 101                         /* check for fit in a hd_struct */
 102                         if (sizeof(sector_t) == sizeof(long) &&
 103                             sizeof(long long) > sizeof(long)) {
 104                                 long pstart = start, plength = length;
 105                                 if (pstart != start || plength != length
 106                                     || pstart < 0 || plength < 0)
 107                                         return -EINVAL;
 108                         }
 109                         part = disk_get_part(disk, partno);
 110                         if (!part)
 111                                 return -ENXIO;
 112                         bdevp = bdget(part_devt(part));
 113                         if (!bdevp) {
 114                                 disk_put_part(part);
 115                                 return -ENOMEM;
 116                         }
 117                         mutex_lock(&bdevp->bd_mutex);
 118                         mutex_lock_nested(&bdev->bd_mutex, 1);
 119                         if (start != part->start_sect) {
 120                                 mutex_unlock(&bdevp->bd_mutex);
 121                                 mutex_unlock(&bdev->bd_mutex);
 122                                 bdput(bdevp);
 123                                 disk_put_part(part);
 124                                 return -EINVAL;
 125                         }
 126                         /* overlap? */
 127                         disk_part_iter_init(&piter, disk,
 128                                             DISK_PITER_INCL_EMPTY);
 129                         while ((lpart = disk_part_iter_next(&piter))) {
 130                                 if (lpart->partno != partno &&
 131                                    !(start + length <= lpart->start_sect ||
 132                                    start >= lpart->start_sect + lpart->nr_sects)
 133                                    ) {
 134                                         disk_part_iter_exit(&piter);
 135                                         mutex_unlock(&bdevp->bd_mutex);
 136                                         mutex_unlock(&bdev->bd_mutex);
 137                                         bdput(bdevp);
 138                                         disk_put_part(part);
 139                                         return -EBUSY;
 140                                 }
 141                         }
 142                         disk_part_iter_exit(&piter);
 143                         part_nr_sects_write(part, (sector_t)length);
 144                         i_size_write(bdevp->bd_inode, p.length);
 145                         mutex_unlock(&bdevp->bd_mutex);
 146                         mutex_unlock(&bdev->bd_mutex);
 147                         bdput(bdevp);
 148                         disk_put_part(part);
 149                         return 0;
 150                 default:
 151                         return -EINVAL;
 152         }
 153 }
 154
 155 /*
 156  * This is an exported API for the block driver, and will not
 157  * acquire bd_mutex. This API should be used in case that
 158  * caller has held bd_mutex already.
 159  */
 160 int __blkdev_reread_part(struct block_device *bdev)
 161 {
 162         struct gendisk *disk = bdev->bd_disk;
 163
 164         if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
 165                 return -EINVAL;
 166         if (!capable(CAP_SYS_ADMIN))
 167                 return -EACCES;
 168
 169         lockdep_assert_held(&bdev->bd_mutex);
 170
 171         return rescan_partitions(disk, bdev);
 172 }
 173 EXPORT_SYMBOL(__blkdev_reread_part);
 174
 175 /*
 176  * This is an exported API for the block driver, and will
 177  * try to acquire bd_mutex. If bd_mutex has been held already
 178  * in current context, please call __blkdev_reread_part().
 179  *
 180  * Make sure the held locks in current context aren't required
 181  * in open()/close() handler and I/O path for avoiding ABBA deadlock:
 182  * - bd_mutex is held before calling block driver's open/close
 183  *   handler
 184  * - reading partition table may submit I/O to the block device
 185  */
 186 int blkdev_reread_part(struct block_device *bdev)
 187 {
 188         int res;
 189
 190         mutex_lock(&bdev->bd_mutex);
 191         res = __blkdev_reread_part(bdev);
 192         mutex_unlock(&bdev->bd_mutex);
 193
 194         return res;
 195 }
 196 EXPORT_SYMBOL(blkdev_reread_part);
 197
 198 static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
 199                 unsigned long arg, unsigned long flags)
 200 {
 201         uint64_t range[2];
 202         uint64_t start, len;
 203
 204         if (!(mode & FMODE_WRITE))
 205                 return -EBADF;
 206
 207         if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 208                 return -EFAULT;
 209
 210         start = range[0];
 211         len = range[1];
 212
 213         if (start & 511)
 214                 return -EINVAL;
 215         if (len & 511)
 216                 return -EINVAL;
 217         start >>= 9;
 218         len >>= 9;
 219
 220         if (start + len > (i_size_read(bdev->bd_inode) >> 9))
 221                 return -EINVAL;
 222         return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
 223 }
 224
 225 static int blk_ioctl_zeroout(struct block_device *bdev, fmode_t mode,
 226                 unsigned long arg)
 227 {
 228         uint64_t range[2];
 229         uint64_t start, 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
 240         if (start & 511)
 241                 return -EINVAL;
 242         if (len & 511)
 243                 return -EINVAL;
 244         start >>= 9;
 245         len >>= 9;
 246
 247         if (start + len > (i_size_read(bdev->bd_inode) >> 9))
 248                 return -EINVAL;
 249
 250         return blkdev_issue_zeroout(bdev, start, len, GFP_KERNEL, false);
 251 }
 252
 253 static int put_ushort(unsigned long arg, unsigned short val)
 254 {
 255         return put_user(val, (unsigned short __user *)arg);
 256 }
 257
 258 static int put_int(unsigned long arg, int val)
 259 {
 260         return put_user(val, (int __user *)arg);
 261 }
 262
 263 static int put_uint(unsigned long arg, unsigned int val)
 264 {
 265         return put_user(val, (unsigned int __user *)arg);
 266 }
 267
 268 static int put_long(unsigned long arg, long val)
 269 {
 270         return put_user(val, (long __user *)arg);
 271 }
 272
 273 static int put_ulong(unsigned long arg, unsigned long val)
 274 {
 275         return put_user(val, (unsigned long __user *)arg);
 276 }
 277
 278 static int put_u64(unsigned long arg, u64 val)
 279 {
 280         return put_user(val, (u64 __user *)arg);
 281 }
 282
 283 int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 284                         unsigned cmd, unsigned long arg)
 285 {
 286         struct gendisk *disk = bdev->bd_disk;
 287
 288         if (disk->fops->ioctl)
 289                 return disk->fops->ioctl(bdev, mode, cmd, arg);
 290
 291         return -ENOTTY;
 292 }
 293 /*
 294  * For the record: _GPL here is only because somebody decided to slap it
 295  * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 296  * at all and could be open-coded without any exports by anybody who cares.
 297  */
 298 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 299
 300 static int blkdev_pr_register(struct block_device *bdev,
 301                 struct pr_registration __user *arg)
 302 {
 303         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 304         struct pr_registration reg;
 305
 306         if (!capable(CAP_SYS_ADMIN))
 307                 return -EPERM;
 308         if (!ops || !ops->pr_register)
 309                 return -EOPNOTSUPP;
 310         if (copy_from_user(&reg, arg, sizeof(reg)))
 311                 return -EFAULT;
 312
 313         if (reg.flags & ~PR_FL_IGNORE_KEY)
 314                 return -EOPNOTSUPP;
 315         return ops->pr_register(bdev, reg.old_key, reg.new_key, reg.flags);
 316 }
 317
 318 static int blkdev_pr_reserve(struct block_device *bdev,
 319                 struct pr_reservation __user *arg)
 320 {
 321         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 322         struct pr_reservation rsv;
 323
 324         if (!capable(CAP_SYS_ADMIN))
 325                 return -EPERM;
 326         if (!ops || !ops->pr_reserve)
 327                 return -EOPNOTSUPP;
 328         if (copy_from_user(&rsv, arg, sizeof(rsv)))
 329                 return -EFAULT;
 330
 331         if (rsv.flags & ~PR_FL_IGNORE_KEY)
 332                 return -EOPNOTSUPP;
 333         return ops->pr_reserve(bdev, rsv.key, rsv.type, rsv.flags);
 334 }
 335
 336 static int blkdev_pr_release(struct block_device *bdev,
 337                 struct pr_reservation __user *arg)
 338 {
 339         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 340         struct pr_reservation rsv;
 341
 342         if (!capable(CAP_SYS_ADMIN))
 343                 return -EPERM;
 344         if (!ops || !ops->pr_release)
 345                 return -EOPNOTSUPP;
 346         if (copy_from_user(&rsv, arg, sizeof(rsv)))
 347                 return -EFAULT;
 348
 349         if (rsv.flags)
 350                 return -EOPNOTSUPP;
 351         return ops->pr_release(bdev, rsv.key, rsv.type);
 352 }
 353
 354 static int blkdev_pr_preempt(struct block_device *bdev,
 355                 struct pr_preempt __user *arg, bool abort)
 356 {
 357         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 358         struct pr_preempt p;
 359
 360         if (!capable(CAP_SYS_ADMIN))
 361                 return -EPERM;
 362         if (!ops || !ops->pr_preempt)
 363                 return -EOPNOTSUPP;
 364         if (copy_from_user(&p, arg, sizeof(p)))
 365                 return -EFAULT;
 366
 367         if (p.flags)
 368                 return -EOPNOTSUPP;
 369         return ops->pr_preempt(bdev, p.old_key, p.new_key, p.type, abort);
 370 }
 371
 372 static int blkdev_pr_clear(struct block_device *bdev,
 373                 struct pr_clear __user *arg)
 374 {
 375         const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
 376         struct pr_clear c;
 377
 378         if (!capable(CAP_SYS_ADMIN))
 379                 return -EPERM;
 380         if (!ops || !ops->pr_clear)
 381                 return -EOPNOTSUPP;
 382         if (copy_from_user(&c, arg, sizeof(c)))
 383                 return -EFAULT;
 384
 385         if (c.flags)
 386                 return -EOPNOTSUPP;
 387         return ops->pr_clear(bdev, c.key);
 388 }
 389
 390 /*
 391  * Is it an unrecognized ioctl? The correct returns are either
 392  * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
 393  * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
 394  * code before returning.
 395  *
 396  * Confused drivers sometimes return EINVAL, which is wrong. It
 397  * means "I understood the ioctl command, but the parameters to
 398  * it were wrong".
 399  *
 400  * We should aim to just fix the broken drivers, the EINVAL case
 401  * should go away.
 402  */
 403 static inline int is_unrecognized_ioctl(int ret)
 404 {
 405         return  ret == -EINVAL ||
 406                 ret == -ENOTTY ||
 407                 ret == -ENOIOCTLCMD;
 408 }
 409
 410 #ifdef CONFIG_FS_DAX
 411 bool blkdev_dax_capable(struct block_device *bdev)
 412 {
 413         struct gendisk *disk = bdev->bd_disk;
 414
 415         if (!disk->fops->direct_access)
 416                 return false;
 417
 418         /*
 419          * If the partition is not aligned on a page boundary, we can't
 420          * do dax I/O to it.
 421          */
 422         if ((bdev->bd_part->start_sect % (PAGE_SIZE / 512))
 423                         || (bdev->bd_part->nr_sects % (PAGE_SIZE / 512)))
 424                 return false;
 425
 426         /*
 427          * If the device has known bad blocks, force all I/O through the
 428          * driver / page cache.
 429          *
 430          * TODO: support finer grained dax error handling
 431          */
 432         if (disk->bb && disk->bb->count)
 433                 return false;
 434
 435         return true;
 436 }
 437 #endif
 438
 439 static int blkdev_flushbuf(struct block_device *bdev, fmode_t mode,
 440                 unsigned cmd, unsigned long arg)
 441 {
 442         int ret;
 443
 444         if (!capable(CAP_SYS_ADMIN))
 445                 return -EACCES;
 446
 447         ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 448         if (!is_unrecognized_ioctl(ret))
 449                 return ret;
 450
 451         fsync_bdev(bdev);
 452         invalidate_bdev(bdev);
 453         return 0;
 454 }
 455
 456 static int blkdev_roset(struct block_device *bdev, fmode_t mode,
 457                 unsigned cmd, unsigned long arg)
 458 {
 459         int ret, n;
 460
 461         ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 462         if (!is_unrecognized_ioctl(ret))
 463                 return ret;
 464         if (!capable(CAP_SYS_ADMIN))
 465                 return -EACCES;
 466         if (get_user(n, (int __user *)arg))
 467                 return -EFAULT;
 468         set_device_ro(bdev, n);
 469         return 0;
 470 }
 471
 472 static int blkdev_getgeo(struct block_device *bdev,
 473                 struct hd_geometry __user *argp)
 474 {
 475         struct gendisk *disk = bdev->bd_disk;
 476         struct hd_geometry geo;
 477         int ret;
 478
 479         if (!argp)
 480                 return -EINVAL;
 481         if (!disk->fops->getgeo)
 482                 return -ENOTTY;
 483
 484         /*
 485          * We need to set the startsect first, the driver may
 486          * want to override it.
 487          */
 488         memset(&geo, 0, sizeof(geo));
 489         geo.start = get_start_sect(bdev);
 490         ret = disk->fops->getgeo(bdev, &geo);
 491         if (ret)
 492                 return ret;
 493         if (copy_to_user(argp, &geo, sizeof(geo)))
 494                 return -EFAULT;
 495         return 0;
 496 }
 497
 498 /* set the logical block size */
 499 static int blkdev_bszset(struct block_device *bdev, fmode_t mode,
 500                 int __user *argp)
 501 {
 502         int ret, n;
 503
 504         if (!capable(CAP_SYS_ADMIN))
 505                 return -EACCES;
 506         if (!argp)
 507                 return -EINVAL;
 508         if (get_user(n, argp))
 509                 return -EFAULT;
 510
 511         if (!(mode & FMODE_EXCL)) {
 512                 bdgrab(bdev);
 513                 if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
 514                         return -EBUSY;
 515         }
 516
 517         ret = set_blocksize(bdev, n);
 518         if (!(mode & FMODE_EXCL))
 519                 blkdev_put(bdev, mode | FMODE_EXCL);
 520         return ret;
 521 }
 522
 523 /*
 524  * always keep this in sync with compat_blkdev_ioctl()
 525  */
 526 int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 527                         unsigned long arg)
 528 {
 529         struct backing_dev_info *bdi;
 530         void __user *argp = (void __user *)arg;
 531         loff_t size;
 532         unsigned int max_sectors;
 533
 534         switch (cmd) {
 535         case BLKFLSBUF:
 536                 return blkdev_flushbuf(bdev, mode, cmd, arg);
 537         case BLKROSET:
 538                 return blkdev_roset(bdev, mode, cmd, arg);
 539         case BLKDISCARD:
 540                 return blk_ioctl_discard(bdev, mode, arg, 0);
 541         case BLKSECDISCARD:
 542                 return blk_ioctl_discard(bdev, mode, arg,
 543                                 BLKDEV_DISCARD_SECURE);
 544         case BLKZEROOUT:
 545                 return blk_ioctl_zeroout(bdev, mode, arg);
 546         case HDIO_GETGEO:
 547                 return blkdev_getgeo(bdev, argp);
 548         case BLKRAGET:
 549         case BLKFRAGET:
 550                 if (!arg)
 551                         return -EINVAL;
 552                 bdi = blk_get_backing_dev_info(bdev);
 553                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 554         case BLKROGET:
 555                 return put_int(arg, bdev_read_only(bdev) != 0);
 556         case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
 557                 return put_int(arg, block_size(bdev));
 558         case BLKSSZGET: /* get block device logical block size */
 559                 return put_int(arg, bdev_logical_block_size(bdev));
 560         case BLKPBSZGET: /* get block device physical block size */
 561                 return put_uint(arg, bdev_physical_block_size(bdev));
 562         case BLKIOMIN:
 563                 return put_uint(arg, bdev_io_min(bdev));
 564         case BLKIOOPT:
 565                 return put_uint(arg, bdev_io_opt(bdev));
 566         case BLKALIGNOFF:
 567                 return put_int(arg, bdev_alignment_offset(bdev));
 568         case BLKDISCARDZEROES:
 569                 return put_uint(arg, bdev_discard_zeroes_data(bdev));
 570         case BLKSECTGET:
 571                 max_sectors = min_t(unsigned int, USHRT_MAX,
 572                                     queue_max_sectors(bdev_get_queue(bdev)));
 573                 return put_ushort(arg, max_sectors);
 574         case BLKROTATIONAL:
 575                 return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
 576         case BLKRASET:
 577         case BLKFRASET:
 578                 if(!capable(CAP_SYS_ADMIN))
 579                         return -EACCES;
 580                 bdi = blk_get_backing_dev_info(bdev);
 581                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 582                 return 0;
 583         case BLKBSZSET:
 584                 return blkdev_bszset(bdev, mode, argp);
 585         case BLKPG:
 586                 return blkpg_ioctl(bdev, argp);
 587         case BLKRRPART:
 588                 return blkdev_reread_part(bdev);
 589         case BLKGETSIZE:
 590                 size = i_size_read(bdev->bd_inode);
 591                 if ((size >> 9) > ~0UL)
 592                         return -EFBIG;
 593                 return put_ulong(arg, size >> 9);
 594         case BLKGETSIZE64:
 595                 return put_u64(arg, i_size_read(bdev->bd_inode));
 596         case BLKTRACESTART:
 597         case BLKTRACESTOP:
 598         case BLKTRACESETUP:
 599         case BLKTRACETEARDOWN:
 600                 return blk_trace_ioctl(bdev, cmd, argp);
 601         case BLKDAXGET:
 602                 return put_int(arg, !!(bdev->bd_inode->i_flags & S_DAX));
 603                 break;
 604         case IOC_PR_REGISTER:
 605                 return blkdev_pr_register(bdev, argp);
 606         case IOC_PR_RESERVE:
 607                 return blkdev_pr_reserve(bdev, argp);
 608         case IOC_PR_RELEASE:
 609                 return blkdev_pr_release(bdev, argp);
 610         case IOC_PR_PREEMPT:
 611                 return blkdev_pr_preempt(bdev, argp, false);
 612         case IOC_PR_PREEMPT_ABORT:
 613                 return blkdev_pr_preempt(bdev, argp, true);
 614         case IOC_PR_CLEAR:
 615                 return blkdev_pr_clear(bdev, argp);
 616         default:
 617                 return __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 618         }
 619 }
 620 EXPORT_SYMBOL_GPL(blkdev_ioctl);