block/ioctl.c

   1 #include <linux/capability.h>
   2 #include <linux/blkdev.h>
   3 #include <linux/blkpg.h>
   4 #include <linux/hdreg.h>
   5 #include <linux/backing-dev.h>
   6 #include <linux/buffer_head.h>
   7 #include <linux/smp_lock.h>
   8 #include <linux/blktrace_api.h>
   9 #include <asm/uaccess.h>
  10
  11 static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
  12 {
  13         struct block_device *bdevp;
  14         struct gendisk *disk;
  15         struct hd_struct *part;
  16         struct blkpg_ioctl_arg a;
  17         struct blkpg_partition p;
  18         struct disk_part_iter piter;
  19         long long start, length;
  20         int partno;
  21
  22         if (!capable(CAP_SYS_ADMIN))
  23                 return -EACCES;
  24         if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
  25                 return -EFAULT;
  26         if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
  27                 return -EFAULT;
  28         disk = bdev->bd_disk;
  29         if (bdev != bdev->bd_contains)
  30                 return -EINVAL;
  31         partno = p.pno;
  32         if (partno <= 0)
  33                 return -EINVAL;
  34         switch (a.op) {
  35                 case BLKPG_ADD_PARTITION:
  36                         start = p.start >> 9;
  37                         length = p.length >> 9;
  38                         /* check for fit in a hd_struct */
  39                         if (sizeof(sector_t) == sizeof(long) &&
  40                             sizeof(long long) > sizeof(long)) {
  41                                 long pstart = start, plength = length;
  42                                 if (pstart != start || plength != length
  43                                     || pstart < 0 || plength < 0)
  44                                         return -EINVAL;
  45                         }
  46
  47                         mutex_lock(&bdev->bd_mutex);
  48
  49                         /* overlap? */
  50                         disk_part_iter_init(&piter, disk,
  51                                             DISK_PITER_INCL_EMPTY);
  52                         while ((part = disk_part_iter_next(&piter))) {
  53                                 if (!(start + length <= part->start_sect ||
  54                                       start >= part->start_sect + part->nr_sects)) {
  55                                         disk_part_iter_exit(&piter);
  56                                         mutex_unlock(&bdev->bd_mutex);
  57                                         return -EBUSY;
  58                                 }
  59                         }
  60                         disk_part_iter_exit(&piter);
  61
  62                         /* all seems OK */
  63                         part = add_partition(disk, partno, start, length,
  64                                              ADDPART_FLAG_NONE);
  65                         mutex_unlock(&bdev->bd_mutex);
  66                         return IS_ERR(part) ? PTR_ERR(part) : 0;
  67                 case BLKPG_DEL_PARTITION:
  68                         part = disk_get_part(disk, partno);
  69                         if (!part)
  70                                 return -ENXIO;
  71
  72                         bdevp = bdget(part_devt(part));
  73                         disk_put_part(part);
  74                         if (!bdevp)
  75                                 return -ENOMEM;
  76
  77                         mutex_lock(&bdevp->bd_mutex);
  78                         if (bdevp->bd_openers) {
  79                                 mutex_unlock(&bdevp->bd_mutex);
  80                                 bdput(bdevp);
  81                                 return -EBUSY;
  82                         }
  83                         /* all seems OK */
  84                         fsync_bdev(bdevp);
  85                         invalidate_bdev(bdevp);
  86
  87                         mutex_lock_nested(&bdev->bd_mutex, 1);
  88                         delete_partition(disk, partno);
  89                         mutex_unlock(&bdev->bd_mutex);
  90                         mutex_unlock(&bdevp->bd_mutex);
  91                         bdput(bdevp);
  92
  93                         return 0;
  94                 default:
  95                         return -EINVAL;
  96         }
  97 }
  98
  99 static int blkdev_reread_part(struct block_device *bdev)
 100 {
 101         struct gendisk *disk = bdev->bd_disk;
 102         int res;
 103
 104         if (!disk_partitionable(disk) || bdev != bdev->bd_contains)
 105                 return -EINVAL;
 106         if (!capable(CAP_SYS_ADMIN))
 107                 return -EACCES;
 108         if (!mutex_trylock(&bdev->bd_mutex))
 109                 return -EBUSY;
 110         res = rescan_partitions(disk, bdev);
 111         mutex_unlock(&bdev->bd_mutex);
 112         return res;
 113 }
 114
 115 static void blk_ioc_discard_endio(struct bio *bio, int err)
 116 {
 117         if (err) {
 118                 if (err == -EOPNOTSUPP)
 119                         set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
 120                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
 121         }
 122         complete(bio->bi_private);
 123 }
 124
 125 static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
 126                              uint64_t len)
 127 {
 128         struct request_queue *q = bdev_get_queue(bdev);
 129         int ret = 0;
 130
 131         if (start & 511)
 132                 return -EINVAL;
 133         if (len & 511)
 134                 return -EINVAL;
 135         start >>= 9;
 136         len >>= 9;
 137
 138         if (start + len > (bdev->bd_inode->i_size >> 9))
 139                 return -EINVAL;
 140
 141         if (!q->prepare_discard_fn)
 142                 return -EOPNOTSUPP;
 143
 144         while (len && !ret) {
 145                 DECLARE_COMPLETION_ONSTACK(wait);
 146                 struct bio *bio;
 147
 148                 bio = bio_alloc(GFP_KERNEL, 0);
 149                 if (!bio)
 150                         return -ENOMEM;
 151
 152                 bio->bi_end_io = blk_ioc_discard_endio;
 153                 bio->bi_bdev = bdev;
 154                 bio->bi_private = &wait;
 155                 bio->bi_sector = start;
 156
 157                 if (len > q->max_hw_sectors) {
 158                         bio->bi_size = q->max_hw_sectors << 9;
 159                         len -= q->max_hw_sectors;
 160                         start += q->max_hw_sectors;
 161                 } else {
 162                         bio->bi_size = len << 9;
 163                         len = 0;
 164                 }
 165                 submit_bio(DISCARD_NOBARRIER, bio);
 166
 167                 wait_for_completion(&wait);
 168
 169                 if (bio_flagged(bio, BIO_EOPNOTSUPP))
 170                         ret = -EOPNOTSUPP;
 171                 else if (!bio_flagged(bio, BIO_UPTODATE))
 172                         ret = -EIO;
 173                 bio_put(bio);
 174         }
 175         return ret;
 176 }
 177
 178 static int put_ushort(unsigned long arg, unsigned short val)
 179 {
 180         return put_user(val, (unsigned short __user *)arg);
 181 }
 182
 183 static int put_int(unsigned long arg, int val)
 184 {
 185         return put_user(val, (int __user *)arg);
 186 }
 187
 188 static int put_long(unsigned long arg, long val)
 189 {
 190         return put_user(val, (long __user *)arg);
 191 }
 192
 193 static int put_ulong(unsigned long arg, unsigned long val)
 194 {
 195         return put_user(val, (unsigned long __user *)arg);
 196 }
 197
 198 static int put_u64(unsigned long arg, u64 val)
 199 {
 200         return put_user(val, (u64 __user *)arg);
 201 }
 202
 203 int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 204                         unsigned cmd, unsigned long arg)
 205 {
 206         struct gendisk *disk = bdev->bd_disk;
 207         int ret;
 208
 209         if (disk->fops->ioctl)
 210                 return disk->fops->ioctl(bdev, mode, cmd, arg);
 211
 212         if (disk->fops->locked_ioctl) {
 213                 lock_kernel();
 214                 ret = disk->fops->locked_ioctl(bdev, mode, cmd, arg);
 215                 unlock_kernel();
 216                 return ret;
 217         }
 218
 219         return -ENOTTY;
 220 }
 221 /*
 222  * For the record: _GPL here is only because somebody decided to slap it
 223  * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 224  * at all and could be open-coded without any exports by anybody who cares.
 225  */
 226 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 227
 228 /*
 229  * always keep this in sync with compat_blkdev_ioctl() and
 230  * compat_blkdev_locked_ioctl()
 231  */
 232 int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 233                         unsigned long arg)
 234 {
 235         struct gendisk *disk = bdev->bd_disk;
 236         struct backing_dev_info *bdi;
 237         loff_t size;
 238         int ret, n;
 239
 240         switch(cmd) {
 241         case BLKFLSBUF:
 242                 if (!capable(CAP_SYS_ADMIN))
 243                         return -EACCES;
 244
 245                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 246                 /* -EINVAL to handle old uncorrected drivers */
 247                 if (ret != -EINVAL && ret != -ENOTTY)
 248                         return ret;
 249
 250                 lock_kernel();
 251                 fsync_bdev(bdev);
 252                 invalidate_bdev(bdev);
 253                 unlock_kernel();
 254                 return 0;
 255
 256         case BLKROSET:
 257                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 258                 /* -EINVAL to handle old uncorrected drivers */
 259                 if (ret != -EINVAL && ret != -ENOTTY)
 260                         return ret;
 261                 if (!capable(CAP_SYS_ADMIN))
 262                         return -EACCES;
 263                 if (get_user(n, (int __user *)(arg)))
 264                         return -EFAULT;
 265                 lock_kernel();
 266                 set_device_ro(bdev, n);
 267                 unlock_kernel();
 268                 return 0;
 269
 270         case BLKDISCARD: {
 271                 uint64_t range[2];
 272
 273                 if (!(mode & FMODE_WRITE))
 274                         return -EBADF;
 275
 276                 if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 277                         return -EFAULT;
 278
 279                 return blk_ioctl_discard(bdev, range[0], range[1]);
 280         }
 281
 282         case HDIO_GETGEO: {
 283                 struct hd_geometry geo;
 284
 285                 if (!arg)
 286                         return -EINVAL;
 287                 if (!disk->fops->getgeo)
 288                         return -ENOTTY;
 289
 290                 /*
 291                  * We need to set the startsect first, the driver may
 292                  * want to override it.
 293                  */
 294                 geo.start = get_start_sect(bdev);
 295                 ret = disk->fops->getgeo(bdev, &geo);
 296                 if (ret)
 297                         return ret;
 298                 if (copy_to_user((struct hd_geometry __user *)arg, &geo,
 299                                         sizeof(geo)))
 300                         return -EFAULT;
 301                 return 0;
 302         }
 303         case BLKRAGET:
 304         case BLKFRAGET:
 305                 if (!arg)
 306                         return -EINVAL;
 307                 bdi = blk_get_backing_dev_info(bdev);
 308                 if (bdi == NULL)
 309                         return -ENOTTY;
 310                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 311         case BLKROGET:
 312                 return put_int(arg, bdev_read_only(bdev) != 0);
 313         case BLKBSZGET: /* get the logical block size (cf. BLKSSZGET) */
 314                 return put_int(arg, block_size(bdev));
 315         case BLKSSZGET: /* get block device hardware sector size */
 316                 return put_int(arg, bdev_hardsect_size(bdev));
 317         case BLKSECTGET:
 318                 return put_ushort(arg, bdev_get_queue(bdev)->max_sectors);
 319         case BLKRASET:
 320         case BLKFRASET:
 321                 if(!capable(CAP_SYS_ADMIN))
 322                         return -EACCES;
 323                 bdi = blk_get_backing_dev_info(bdev);
 324                 if (bdi == NULL)
 325                         return -ENOTTY;
 326                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 327                 return 0;
 328         case BLKBSZSET:
 329                 /* set the logical block size */
 330                 if (!capable(CAP_SYS_ADMIN))
 331                         return -EACCES;
 332                 if (!arg)
 333                         return -EINVAL;
 334                 if (get_user(n, (int __user *) arg))
 335                         return -EFAULT;
 336                 if (!(mode & FMODE_EXCL) && bd_claim(bdev, &bdev) < 0)
 337                         return -EBUSY;
 338                 ret = set_blocksize(bdev, n);
 339                 if (!(mode & FMODE_EXCL))
 340                         bd_release(bdev);
 341                 return ret;
 342         case BLKPG:
 343                 lock_kernel();
 344                 ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 345                 unlock_kernel();
 346                 break;
 347         case BLKRRPART:
 348                 lock_kernel();
 349                 ret = blkdev_reread_part(bdev);
 350                 unlock_kernel();
 351                 break;
 352         case BLKGETSIZE:
 353                 size = bdev->bd_inode->i_size;
 354                 if ((size >> 9) > ~0UL)
 355                         return -EFBIG;
 356                 return put_ulong(arg, size >> 9);
 357         case BLKGETSIZE64:
 358                 return put_u64(arg, bdev->bd_inode->i_size);
 359         case BLKTRACESTART:
 360         case BLKTRACESTOP:
 361         case BLKTRACESETUP:
 362         case BLKTRACETEARDOWN:
 363                 lock_kernel();
 364                 ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
 365                 unlock_kernel();
 366                 break;
 367         default:
 368                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 369         }
 370         return ret;
 371 }
 372 EXPORT_SYMBOL_GPL(blkdev_ioctl);