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
 150                 bio->bi_end_io = blk_ioc_discard_endio;
 151                 bio->bi_bdev = bdev;
 152                 bio->bi_private = &wait;
 153                 bio->bi_sector = start;
 154
 155                 if (len > queue_max_hw_sectors(q)) {
 156                         bio->bi_size = queue_max_hw_sectors(q) << 9;
 157                         len -= queue_max_hw_sectors(q);
 158                         start += queue_max_hw_sectors(q);
 159                 } else {
 160                         bio->bi_size = len << 9;
 161                         len = 0;
 162                 }
 163                 submit_bio(DISCARD_NOBARRIER, bio);
 164
 165                 wait_for_completion(&wait);
 166
 167                 if (bio_flagged(bio, BIO_EOPNOTSUPP))
 168                         ret = -EOPNOTSUPP;
 169                 else if (!bio_flagged(bio, BIO_UPTODATE))
 170                         ret = -EIO;
 171                 bio_put(bio);
 172         }
 173         return ret;
 174 }
 175
 176 static int put_ushort(unsigned long arg, unsigned short val)
 177 {
 178         return put_user(val, (unsigned short __user *)arg);
 179 }
 180
 181 static int put_int(unsigned long arg, int val)
 182 {
 183         return put_user(val, (int __user *)arg);
 184 }
 185
 186 static int put_long(unsigned long arg, long val)
 187 {
 188         return put_user(val, (long __user *)arg);
 189 }
 190
 191 static int put_ulong(unsigned long arg, unsigned long val)
 192 {
 193         return put_user(val, (unsigned long __user *)arg);
 194 }
 195
 196 static int put_u64(unsigned long arg, u64 val)
 197 {
 198         return put_user(val, (u64 __user *)arg);
 199 }
 200
 201 int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 202                         unsigned cmd, unsigned long arg)
 203 {
 204         struct gendisk *disk = bdev->bd_disk;
 205         int ret;
 206
 207         if (disk->fops->ioctl)
 208                 return disk->fops->ioctl(bdev, mode, cmd, arg);
 209
 210         if (disk->fops->locked_ioctl) {
 211                 lock_kernel();
 212                 ret = disk->fops->locked_ioctl(bdev, mode, cmd, arg);
 213                 unlock_kernel();
 214                 return ret;
 215         }
 216
 217         return -ENOTTY;
 218 }
 219 /*
 220  * For the record: _GPL here is only because somebody decided to slap it
 221  * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 222  * at all and could be open-coded without any exports by anybody who cares.
 223  */
 224 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 225
 226 /*
 227  * always keep this in sync with compat_blkdev_ioctl() and
 228  * compat_blkdev_locked_ioctl()
 229  */
 230 int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 231                         unsigned long arg)
 232 {
 233         struct gendisk *disk = bdev->bd_disk;
 234         struct backing_dev_info *bdi;
 235         loff_t size;
 236         int ret, n;
 237
 238         switch(cmd) {
 239         case BLKFLSBUF:
 240                 if (!capable(CAP_SYS_ADMIN))
 241                         return -EACCES;
 242
 243                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 244                 /* -EINVAL to handle old uncorrected drivers */
 245                 if (ret != -EINVAL && ret != -ENOTTY)
 246                         return ret;
 247
 248                 lock_kernel();
 249                 fsync_bdev(bdev);
 250                 invalidate_bdev(bdev);
 251                 unlock_kernel();
 252                 return 0;
 253
 254         case BLKROSET:
 255                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 256                 /* -EINVAL to handle old uncorrected drivers */
 257                 if (ret != -EINVAL && ret != -ENOTTY)
 258                         return ret;
 259                 if (!capable(CAP_SYS_ADMIN))
 260                         return -EACCES;
 261                 if (get_user(n, (int __user *)(arg)))
 262                         return -EFAULT;
 263                 lock_kernel();
 264                 set_device_ro(bdev, n);
 265                 unlock_kernel();
 266                 return 0;
 267
 268         case BLKDISCARD: {
 269                 uint64_t range[2];
 270
 271                 if (!(mode & FMODE_WRITE))
 272                         return -EBADF;
 273
 274                 if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 275                         return -EFAULT;
 276
 277                 return blk_ioctl_discard(bdev, range[0], range[1]);
 278         }
 279
 280         case HDIO_GETGEO: {
 281                 struct hd_geometry geo;
 282
 283                 if (!arg)
 284                         return -EINVAL;
 285                 if (!disk->fops->getgeo)
 286                         return -ENOTTY;
 287
 288                 /*
 289                  * We need to set the startsect first, the driver may
 290                  * want to override it.
 291                  */
 292                 geo.start = get_start_sect(bdev);
 293                 ret = disk->fops->getgeo(bdev, &geo);
 294                 if (ret)
 295                         return ret;
 296                 if (copy_to_user((struct hd_geometry __user *)arg, &geo,
 297                                         sizeof(geo)))
 298                         return -EFAULT;
 299                 return 0;
 300         }
 301         case BLKRAGET:
 302         case BLKFRAGET:
 303                 if (!arg)
 304                         return -EINVAL;
 305                 bdi = blk_get_backing_dev_info(bdev);
 306                 if (bdi == NULL)
 307                         return -ENOTTY;
 308                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 309         case BLKROGET:
 310                 return put_int(arg, bdev_read_only(bdev) != 0);
 311         case BLKBSZGET: /* get the logical block size (cf. BLKSSZGET) */
 312                 return put_int(arg, block_size(bdev));
 313         case BLKSSZGET: /* get block device hardware sector size */
 314                 return put_int(arg, bdev_logical_block_size(bdev));
 315         case BLKSECTGET:
 316                 return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev)));
 317         case BLKRASET:
 318         case BLKFRASET:
 319                 if(!capable(CAP_SYS_ADMIN))
 320                         return -EACCES;
 321                 bdi = blk_get_backing_dev_info(bdev);
 322                 if (bdi == NULL)
 323                         return -ENOTTY;
 324                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 325                 return 0;
 326         case BLKBSZSET:
 327                 /* set the logical block size */
 328                 if (!capable(CAP_SYS_ADMIN))
 329                         return -EACCES;
 330                 if (!arg)
 331                         return -EINVAL;
 332                 if (get_user(n, (int __user *) arg))
 333                         return -EFAULT;
 334                 if (!(mode & FMODE_EXCL) && bd_claim(bdev, &bdev) < 0)
 335                         return -EBUSY;
 336                 ret = set_blocksize(bdev, n);
 337                 if (!(mode & FMODE_EXCL))
 338                         bd_release(bdev);
 339                 return ret;
 340         case BLKPG:
 341                 lock_kernel();
 342                 ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 343                 unlock_kernel();
 344                 break;
 345         case BLKRRPART:
 346                 lock_kernel();
 347                 ret = blkdev_reread_part(bdev);
 348                 unlock_kernel();
 349                 break;
 350         case BLKGETSIZE:
 351                 size = bdev->bd_inode->i_size;
 352                 if ((size >> 9) > ~0UL)
 353                         return -EFBIG;
 354                 return put_ulong(arg, size >> 9);
 355         case BLKGETSIZE64:
 356                 return put_u64(arg, bdev->bd_inode->i_size);
 357         case BLKTRACESTART:
 358         case BLKTRACESTOP:
 359         case BLKTRACESETUP:
 360         case BLKTRACETEARDOWN:
 361                 lock_kernel();
 362                 ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
 363                 unlock_kernel();
 364                 break;
 365         default:
 366                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 367         }
 368         return ret;
 369 }
 370 EXPORT_SYMBOL_GPL(blkdev_ioctl);