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 <asm/uaccess.h>
  11
  12 static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
  13 {
  14         struct block_device *bdevp;
  15         struct gendisk *disk;
  16         struct hd_struct *part, *lpart;
  17         struct blkpg_ioctl_arg a;
  18         struct blkpg_partition p;
  19         struct disk_part_iter piter;
  20         long long start, length;
  21         int partno;
  22
  23         if (!capable(CAP_SYS_ADMIN))
  24                 return -EACCES;
  25         if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
  26                 return -EFAULT;
  27         if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
  28                 return -EFAULT;
  29         disk = bdev->bd_disk;
  30         if (bdev != bdev->bd_contains)
  31                 return -EINVAL;
  32         partno = p.pno;
  33         if (partno <= 0)
  34                 return -EINVAL;
  35         switch (a.op) {
  36                 case BLKPG_ADD_PARTITION:
  37                         start = p.start >> 9;
  38                         length = p.length >> 9;
  39                         /* check for fit in a hd_struct */
  40                         if (sizeof(sector_t) == sizeof(long) &&
  41                             sizeof(long long) > sizeof(long)) {
  42                                 long pstart = start, plength = length;
  43                                 if (pstart != start || plength != length
  44                                     || pstart < 0 || plength < 0 || partno > 65535)
  45                                         return -EINVAL;
  46                         }
  47
  48                         mutex_lock(&bdev->bd_mutex);
  49
  50                         /* overlap? */
  51                         disk_part_iter_init(&piter, disk,
  52                                             DISK_PITER_INCL_EMPTY);
  53                         while ((part = disk_part_iter_next(&piter))) {
  54                                 if (!(start + length <= part->start_sect ||
  55                                       start >= part->start_sect + part->nr_sects)) {
  56                                         disk_part_iter_exit(&piter);
  57                                         mutex_unlock(&bdev->bd_mutex);
  58                                         return -EBUSY;
  59                                 }
  60                         }
  61                         disk_part_iter_exit(&piter);
  62
  63                         /* all seems OK */
  64                         part = add_partition(disk, partno, start, length,
  65                                              ADDPART_FLAG_NONE, NULL);
  66                         mutex_unlock(&bdev->bd_mutex);
  67                         return PTR_ERR_OR_ZERO(part);
  68                 case BLKPG_DEL_PARTITION:
  69                         part = disk_get_part(disk, partno);
  70                         if (!part)
  71                                 return -ENXIO;
  72
  73                         bdevp = bdget(part_devt(part));
  74                         disk_put_part(part);
  75                         if (!bdevp)
  76                                 return -ENOMEM;
  77
  78                         mutex_lock(&bdevp->bd_mutex);
  79                         if (bdevp->bd_openers) {
  80                                 mutex_unlock(&bdevp->bd_mutex);
  81                                 bdput(bdevp);
  82                                 return -EBUSY;
  83                         }
  84                         /* all seems OK */
  85                         fsync_bdev(bdevp);
  86                         invalidate_bdev(bdevp);
  87
  88                         mutex_lock_nested(&bdev->bd_mutex, 1);
  89                         delete_partition(disk, partno);
  90                         mutex_unlock(&bdev->bd_mutex);
  91                         mutex_unlock(&bdevp->bd_mutex);
  92                         bdput(bdevp);
  93
  94                         return 0;
  95                 case BLKPG_RESIZE_PARTITION:
  96                         start = p.start >> 9;
  97                         /* new length of partition in bytes */
  98                         length = p.length >> 9;
  99                         /* check for fit in a hd_struct */
 100                         if (sizeof(sector_t) == sizeof(long) &&
 101                             sizeof(long long) > sizeof(long)) {
 102                                 long pstart = start, plength = length;
 103                                 if (pstart != start || plength != length
 104                                     || pstart < 0 || plength < 0)
 105                                         return -EINVAL;
 106                         }
 107                         part = disk_get_part(disk, partno);
 108                         if (!part)
 109                                 return -ENXIO;
 110                         bdevp = bdget(part_devt(part));
 111                         if (!bdevp) {
 112                                 disk_put_part(part);
 113                                 return -ENOMEM;
 114                         }
 115                         mutex_lock(&bdevp->bd_mutex);
 116                         mutex_lock_nested(&bdev->bd_mutex, 1);
 117                         if (start != part->start_sect) {
 118                                 mutex_unlock(&bdevp->bd_mutex);
 119                                 mutex_unlock(&bdev->bd_mutex);
 120                                 bdput(bdevp);
 121                                 disk_put_part(part);
 122                                 return -EINVAL;
 123                         }
 124                         /* overlap? */
 125                         disk_part_iter_init(&piter, disk,
 126                                             DISK_PITER_INCL_EMPTY);
 127                         while ((lpart = disk_part_iter_next(&piter))) {
 128                                 if (lpart->partno != partno &&
 129                                    !(start + length <= lpart->start_sect ||
 130                                    start >= lpart->start_sect + lpart->nr_sects)
 131                                    ) {
 132                                         disk_part_iter_exit(&piter);
 133                                         mutex_unlock(&bdevp->bd_mutex);
 134                                         mutex_unlock(&bdev->bd_mutex);
 135                                         bdput(bdevp);
 136                                         disk_put_part(part);
 137                                         return -EBUSY;
 138                                 }
 139                         }
 140                         disk_part_iter_exit(&piter);
 141                         part_nr_sects_write(part, (sector_t)length);
 142                         i_size_write(bdevp->bd_inode, p.length);
 143                         mutex_unlock(&bdevp->bd_mutex);
 144                         mutex_unlock(&bdev->bd_mutex);
 145                         bdput(bdevp);
 146                         disk_put_part(part);
 147                         return 0;
 148                 default:
 149                         return -EINVAL;
 150         }
 151 }
 152
 153 /*
 154  * This is an exported API for the block driver, and will not
 155  * acquire bd_mutex. This API should be used in case that
 156  * caller has held bd_mutex already.
 157  */
 158 int __blkdev_reread_part(struct block_device *bdev)
 159 {
 160         struct gendisk *disk = bdev->bd_disk;
 161
 162         if (!disk_part_scan_enabled(disk) || bdev != bdev->bd_contains)
 163                 return -EINVAL;
 164         if (!capable(CAP_SYS_ADMIN))
 165                 return -EACCES;
 166
 167         lockdep_assert_held(&bdev->bd_mutex);
 168
 169         return rescan_partitions(disk, bdev);
 170 }
 171 EXPORT_SYMBOL(__blkdev_reread_part);
 172
 173 /*
 174  * This is an exported API for the block driver, and will
 175  * try to acquire bd_mutex. If bd_mutex has been held already
 176  * in current context, please call __blkdev_reread_part().
 177  *
 178  * Make sure the held locks in current context aren't required
 179  * in open()/close() handler and I/O path for avoiding ABBA deadlock:
 180  * - bd_mutex is held before calling block driver's open/close
 181  *   handler
 182  * - reading partition table may submit I/O to the block device
 183  */
 184 int blkdev_reread_part(struct block_device *bdev)
 185 {
 186         int res;
 187
 188         mutex_lock(&bdev->bd_mutex);
 189         res = __blkdev_reread_part(bdev);
 190         mutex_unlock(&bdev->bd_mutex);
 191
 192         return res;
 193 }
 194 EXPORT_SYMBOL(blkdev_reread_part);
 195
 196 static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
 197                              uint64_t len, int secure)
 198 {
 199         unsigned long flags = 0;
 200
 201         if (start & 511)
 202                 return -EINVAL;
 203         if (len & 511)
 204                 return -EINVAL;
 205         start >>= 9;
 206         len >>= 9;
 207
 208         if (start + len > (i_size_read(bdev->bd_inode) >> 9))
 209                 return -EINVAL;
 210         if (secure)
 211                 flags |= BLKDEV_DISCARD_SECURE;
 212         return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
 213 }
 214
 215 static int blk_ioctl_zeroout(struct block_device *bdev, uint64_t start,
 216                              uint64_t len)
 217 {
 218         if (start & 511)
 219                 return -EINVAL;
 220         if (len & 511)
 221                 return -EINVAL;
 222         start >>= 9;
 223         len >>= 9;
 224
 225         if (start + len > (i_size_read(bdev->bd_inode) >> 9))
 226                 return -EINVAL;
 227
 228         return blkdev_issue_zeroout(bdev, start, len, GFP_KERNEL, false);
 229 }
 230
 231 static int put_ushort(unsigned long arg, unsigned short val)
 232 {
 233         return put_user(val, (unsigned short __user *)arg);
 234 }
 235
 236 static int put_int(unsigned long arg, int val)
 237 {
 238         return put_user(val, (int __user *)arg);
 239 }
 240
 241 static int put_uint(unsigned long arg, unsigned int val)
 242 {
 243         return put_user(val, (unsigned int __user *)arg);
 244 }
 245
 246 static int put_long(unsigned long arg, long val)
 247 {
 248         return put_user(val, (long __user *)arg);
 249 }
 250
 251 static int put_ulong(unsigned long arg, unsigned long val)
 252 {
 253         return put_user(val, (unsigned long __user *)arg);
 254 }
 255
 256 static int put_u64(unsigned long arg, u64 val)
 257 {
 258         return put_user(val, (u64 __user *)arg);
 259 }
 260
 261 int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 262                         unsigned cmd, unsigned long arg)
 263 {
 264         struct gendisk *disk = bdev->bd_disk;
 265
 266         if (disk->fops->ioctl)
 267                 return disk->fops->ioctl(bdev, mode, cmd, arg);
 268
 269         return -ENOTTY;
 270 }
 271 /*
 272  * For the record: _GPL here is only because somebody decided to slap it
 273  * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 274  * at all and could be open-coded without any exports by anybody who cares.
 275  */
 276 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 277
 278 /*
 279  * Is it an unrecognized ioctl? The correct returns are either
 280  * ENOTTY (final) or ENOIOCTLCMD ("I don't know this one, try a
 281  * fallback"). ENOIOCTLCMD gets turned into ENOTTY by the ioctl
 282  * code before returning.
 283  *
 284  * Confused drivers sometimes return EINVAL, which is wrong. It
 285  * means "I understood the ioctl command, but the parameters to
 286  * it were wrong".
 287  *
 288  * We should aim to just fix the broken drivers, the EINVAL case
 289  * should go away.
 290  */
 291 static inline int is_unrecognized_ioctl(int ret)
 292 {
 293         return  ret == -EINVAL ||
 294                 ret == -ENOTTY ||
 295                 ret == -ENOIOCTLCMD;
 296 }
 297
 298 /*
 299  * always keep this in sync with compat_blkdev_ioctl()
 300  */
 301 int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 302                         unsigned long arg)
 303 {
 304         struct gendisk *disk = bdev->bd_disk;
 305         struct backing_dev_info *bdi;
 306         loff_t size;
 307         int ret, n;
 308         unsigned int max_sectors;
 309
 310         switch(cmd) {
 311         case BLKFLSBUF:
 312                 if (!capable(CAP_SYS_ADMIN))
 313                         return -EACCES;
 314
 315                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 316                 if (!is_unrecognized_ioctl(ret))
 317                         return ret;
 318
 319                 fsync_bdev(bdev);
 320                 invalidate_bdev(bdev);
 321                 return 0;
 322
 323         case BLKROSET:
 324                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 325                 if (!is_unrecognized_ioctl(ret))
 326                         return ret;
 327                 if (!capable(CAP_SYS_ADMIN))
 328                         return -EACCES;
 329                 if (get_user(n, (int __user *)(arg)))
 330                         return -EFAULT;
 331                 set_device_ro(bdev, n);
 332                 return 0;
 333
 334         case BLKDISCARD:
 335         case BLKSECDISCARD: {
 336                 uint64_t range[2];
 337
 338                 if (!(mode & FMODE_WRITE))
 339                         return -EBADF;
 340
 341                 if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 342                         return -EFAULT;
 343
 344                 return blk_ioctl_discard(bdev, range[0], range[1],
 345                                          cmd == BLKSECDISCARD);
 346         }
 347         case BLKZEROOUT: {
 348                 uint64_t range[2];
 349
 350                 if (!(mode & FMODE_WRITE))
 351                         return -EBADF;
 352
 353                 if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 354                         return -EFAULT;
 355
 356                 return blk_ioctl_zeroout(bdev, range[0], range[1]);
 357         }
 358
 359         case HDIO_GETGEO: {
 360                 struct hd_geometry geo;
 361
 362                 if (!arg)
 363                         return -EINVAL;
 364                 if (!disk->fops->getgeo)
 365                         return -ENOTTY;
 366
 367                 /*
 368                  * We need to set the startsect first, the driver may
 369                  * want to override it.
 370                  */
 371                 memset(&geo, 0, sizeof(geo));
 372                 geo.start = get_start_sect(bdev);
 373                 ret = disk->fops->getgeo(bdev, &geo);
 374                 if (ret)
 375                         return ret;
 376                 if (copy_to_user((struct hd_geometry __user *)arg, &geo,
 377                                         sizeof(geo)))
 378                         return -EFAULT;
 379                 return 0;
 380         }
 381         case BLKRAGET:
 382         case BLKFRAGET:
 383                 if (!arg)
 384                         return -EINVAL;
 385                 bdi = blk_get_backing_dev_info(bdev);
 386                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 387         case BLKROGET:
 388                 return put_int(arg, bdev_read_only(bdev) != 0);
 389         case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
 390                 return put_int(arg, block_size(bdev));
 391         case BLKSSZGET: /* get block device logical block size */
 392                 return put_int(arg, bdev_logical_block_size(bdev));
 393         case BLKPBSZGET: /* get block device physical block size */
 394                 return put_uint(arg, bdev_physical_block_size(bdev));
 395         case BLKIOMIN:
 396                 return put_uint(arg, bdev_io_min(bdev));
 397         case BLKIOOPT:
 398                 return put_uint(arg, bdev_io_opt(bdev));
 399         case BLKALIGNOFF:
 400                 return put_int(arg, bdev_alignment_offset(bdev));
 401         case BLKDISCARDZEROES:
 402                 return put_uint(arg, bdev_discard_zeroes_data(bdev));
 403         case BLKSECTGET:
 404                 max_sectors = min_t(unsigned int, USHRT_MAX,
 405                                     queue_max_sectors(bdev_get_queue(bdev)));
 406                 return put_ushort(arg, max_sectors);
 407         case BLKROTATIONAL:
 408                 return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
 409         case BLKRASET:
 410         case BLKFRASET:
 411                 if(!capable(CAP_SYS_ADMIN))
 412                         return -EACCES;
 413                 bdi = blk_get_backing_dev_info(bdev);
 414                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 415                 return 0;
 416         case BLKBSZSET:
 417                 /* set the logical block size */
 418                 if (!capable(CAP_SYS_ADMIN))
 419                         return -EACCES;
 420                 if (!arg)
 421                         return -EINVAL;
 422                 if (get_user(n, (int __user *) arg))
 423                         return -EFAULT;
 424                 if (!(mode & FMODE_EXCL)) {
 425                         bdgrab(bdev);
 426                         if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
 427                                 return -EBUSY;
 428                 }
 429                 ret = set_blocksize(bdev, n);
 430                 if (!(mode & FMODE_EXCL))
 431                         blkdev_put(bdev, mode | FMODE_EXCL);
 432                 return ret;
 433         case BLKPG:
 434                 ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 435                 break;
 436         case BLKRRPART:
 437                 ret = blkdev_reread_part(bdev);
 438                 break;
 439         case BLKGETSIZE:
 440                 size = i_size_read(bdev->bd_inode);
 441                 if ((size >> 9) > ~0UL)
 442                         return -EFBIG;
 443                 return put_ulong(arg, size >> 9);
 444         case BLKGETSIZE64:
 445                 return put_u64(arg, i_size_read(bdev->bd_inode));
 446         case BLKTRACESTART:
 447         case BLKTRACESTOP:
 448         case BLKTRACESETUP:
 449         case BLKTRACETEARDOWN:
 450                 ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
 451                 break;
 452         default:
 453                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 454         }
 455         return ret;
 456 }
 457 EXPORT_SYMBOL_GPL(blkdev_ioctl);