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 int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
 116                              uint64_t len)
 117 {
 118         if (start & 511)
 119                 return -EINVAL;
 120         if (len & 511)
 121                 return -EINVAL;
 122         start >>= 9;
 123         len >>= 9;
 124
 125         if (start + len > (bdev->bd_inode->i_size >> 9))
 126                 return -EINVAL;
 127         return blkdev_issue_discard(bdev, start, len, GFP_KERNEL,
 128                                     DISCARD_FL_WAIT);
 129 }
 130
 131 static int put_ushort(unsigned long arg, unsigned short val)
 132 {
 133         return put_user(val, (unsigned short __user *)arg);
 134 }
 135
 136 static int put_int(unsigned long arg, int val)
 137 {
 138         return put_user(val, (int __user *)arg);
 139 }
 140
 141 static int put_uint(unsigned long arg, unsigned int val)
 142 {
 143         return put_user(val, (unsigned int __user *)arg);
 144 }
 145
 146 static int put_long(unsigned long arg, long val)
 147 {
 148         return put_user(val, (long __user *)arg);
 149 }
 150
 151 static int put_ulong(unsigned long arg, unsigned long val)
 152 {
 153         return put_user(val, (unsigned long __user *)arg);
 154 }
 155
 156 static int put_u64(unsigned long arg, u64 val)
 157 {
 158         return put_user(val, (u64 __user *)arg);
 159 }
 160
 161 int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 162                         unsigned cmd, unsigned long arg)
 163 {
 164         struct gendisk *disk = bdev->bd_disk;
 165         int ret;
 166
 167         if (disk->fops->ioctl)
 168                 return disk->fops->ioctl(bdev, mode, cmd, arg);
 169
 170         if (disk->fops->locked_ioctl) {
 171                 lock_kernel();
 172                 ret = disk->fops->locked_ioctl(bdev, mode, cmd, arg);
 173                 unlock_kernel();
 174                 return ret;
 175         }
 176
 177         return -ENOTTY;
 178 }
 179 /*
 180  * For the record: _GPL here is only because somebody decided to slap it
 181  * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 182  * at all and could be open-coded without any exports by anybody who cares.
 183  */
 184 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 185
 186 /*
 187  * always keep this in sync with compat_blkdev_ioctl() and
 188  * compat_blkdev_locked_ioctl()
 189  */
 190 int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 191                         unsigned long arg)
 192 {
 193         struct gendisk *disk = bdev->bd_disk;
 194         struct backing_dev_info *bdi;
 195         loff_t size;
 196         int ret, n;
 197
 198         switch(cmd) {
 199         case BLKFLSBUF:
 200                 if (!capable(CAP_SYS_ADMIN))
 201                         return -EACCES;
 202
 203                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 204                 /* -EINVAL to handle old uncorrected drivers */
 205                 if (ret != -EINVAL && ret != -ENOTTY)
 206                         return ret;
 207
 208                 lock_kernel();
 209                 fsync_bdev(bdev);
 210                 invalidate_bdev(bdev);
 211                 unlock_kernel();
 212                 return 0;
 213
 214         case BLKROSET:
 215                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 216                 /* -EINVAL to handle old uncorrected drivers */
 217                 if (ret != -EINVAL && ret != -ENOTTY)
 218                         return ret;
 219                 if (!capable(CAP_SYS_ADMIN))
 220                         return -EACCES;
 221                 if (get_user(n, (int __user *)(arg)))
 222                         return -EFAULT;
 223                 lock_kernel();
 224                 set_device_ro(bdev, n);
 225                 unlock_kernel();
 226                 return 0;
 227
 228         case BLKDISCARD: {
 229                 uint64_t range[2];
 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                 return blk_ioctl_discard(bdev, range[0], range[1]);
 238         }
 239
 240         case HDIO_GETGEO: {
 241                 struct hd_geometry geo;
 242
 243                 if (!arg)
 244                         return -EINVAL;
 245                 if (!disk->fops->getgeo)
 246                         return -ENOTTY;
 247
 248                 /*
 249                  * We need to set the startsect first, the driver may
 250                  * want to override it.
 251                  */
 252                 geo.start = get_start_sect(bdev);
 253                 ret = disk->fops->getgeo(bdev, &geo);
 254                 if (ret)
 255                         return ret;
 256                 if (copy_to_user((struct hd_geometry __user *)arg, &geo,
 257                                         sizeof(geo)))
 258                         return -EFAULT;
 259                 return 0;
 260         }
 261         case BLKRAGET:
 262         case BLKFRAGET:
 263                 if (!arg)
 264                         return -EINVAL;
 265                 bdi = blk_get_backing_dev_info(bdev);
 266                 if (bdi == NULL)
 267                         return -ENOTTY;
 268                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 269         case BLKROGET:
 270                 return put_int(arg, bdev_read_only(bdev) != 0);
 271         case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
 272                 return put_int(arg, block_size(bdev));
 273         case BLKSSZGET: /* get block device logical block size */
 274                 return put_int(arg, bdev_logical_block_size(bdev));
 275         case BLKPBSZGET: /* get block device physical block size */
 276                 return put_uint(arg, bdev_physical_block_size(bdev));
 277         case BLKIOMIN:
 278                 return put_uint(arg, bdev_io_min(bdev));
 279         case BLKIOOPT:
 280                 return put_uint(arg, bdev_io_opt(bdev));
 281         case BLKALIGNOFF:
 282                 return put_int(arg, bdev_alignment_offset(bdev));
 283         case BLKSECTGET:
 284                 return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev)));
 285         case BLKRASET:
 286         case BLKFRASET:
 287                 if(!capable(CAP_SYS_ADMIN))
 288                         return -EACCES;
 289                 bdi = blk_get_backing_dev_info(bdev);
 290                 if (bdi == NULL)
 291                         return -ENOTTY;
 292                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 293                 return 0;
 294         case BLKBSZSET:
 295                 /* set the logical block size */
 296                 if (!capable(CAP_SYS_ADMIN))
 297                         return -EACCES;
 298                 if (!arg)
 299                         return -EINVAL;
 300                 if (get_user(n, (int __user *) arg))
 301                         return -EFAULT;
 302                 if (!(mode & FMODE_EXCL) && bd_claim(bdev, &bdev) < 0)
 303                         return -EBUSY;
 304                 ret = set_blocksize(bdev, n);
 305                 if (!(mode & FMODE_EXCL))
 306                         bd_release(bdev);
 307                 return ret;
 308         case BLKPG:
 309                 lock_kernel();
 310                 ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 311                 unlock_kernel();
 312                 break;
 313         case BLKRRPART:
 314                 lock_kernel();
 315                 ret = blkdev_reread_part(bdev);
 316                 unlock_kernel();
 317                 break;
 318         case BLKGETSIZE:
 319                 size = bdev->bd_inode->i_size;
 320                 if ((size >> 9) > ~0UL)
 321                         return -EFBIG;
 322                 return put_ulong(arg, size >> 9);
 323         case BLKGETSIZE64:
 324                 return put_u64(arg, bdev->bd_inode->i_size);
 325         case BLKTRACESTART:
 326         case BLKTRACESTOP:
 327         case BLKTRACESETUP:
 328         case BLKTRACETEARDOWN:
 329                 lock_kernel();
 330                 ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
 331                 unlock_kernel();
 332                 break;
 333         default:
 334                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 335         }
 336         return ret;
 337 }
 338 EXPORT_SYMBOL_GPL(blkdev_ioctl);