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         int err;
  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)
  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                         err = add_partition(disk, partno, start, length,
  65                                             ADDPART_FLAG_NONE);
  66                         mutex_unlock(&bdev->bd_mutex);
  67                         return err;
  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                 default:
  96                         return -EINVAL;
  97         }
  98 }
  99
 100 static int blkdev_reread_part(struct block_device *bdev)
 101 {
 102         struct gendisk *disk = bdev->bd_disk;
 103         int res;
 104
 105         if (!disk_partitionable(disk) || bdev != bdev->bd_contains)
 106                 return -EINVAL;
 107         if (!capable(CAP_SYS_ADMIN))
 108                 return -EACCES;
 109         if (!mutex_trylock(&bdev->bd_mutex))
 110                 return -EBUSY;
 111         res = rescan_partitions(disk, bdev);
 112         mutex_unlock(&bdev->bd_mutex);
 113         return res;
 114 }
 115
 116 static void blk_ioc_discard_endio(struct bio *bio, int err)
 117 {
 118         if (err) {
 119                 if (err == -EOPNOTSUPP)
 120                         set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
 121                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
 122         }
 123         complete(bio->bi_private);
 124 }
 125
 126 static int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
 127                              uint64_t len)
 128 {
 129         struct request_queue *q = bdev_get_queue(bdev);
 130         int ret = 0;
 131
 132         if (start & 511)
 133                 return -EINVAL;
 134         if (len & 511)
 135                 return -EINVAL;
 136         start >>= 9;
 137         len >>= 9;
 138
 139         if (start + len > (bdev->bd_inode->i_size >> 9))
 140                 return -EINVAL;
 141
 142         if (!q->prepare_discard_fn)
 143                 return -EOPNOTSUPP;
 144
 145         while (len && !ret) {
 146                 DECLARE_COMPLETION_ONSTACK(wait);
 147                 struct bio *bio;
 148
 149                 bio = bio_alloc(GFP_KERNEL, 0);
 150                 if (!bio)
 151                         return -ENOMEM;
 152
 153                 bio->bi_end_io = blk_ioc_discard_endio;
 154                 bio->bi_bdev = bdev;
 155                 bio->bi_private = &wait;
 156                 bio->bi_sector = start;
 157
 158                 if (len > q->max_hw_sectors) {
 159                         bio->bi_size = q->max_hw_sectors << 9;
 160                         len -= q->max_hw_sectors;
 161                         start += q->max_hw_sectors;
 162                 } else {
 163                         bio->bi_size = len << 9;
 164                         len = 0;
 165                 }
 166                 submit_bio(DISCARD_NOBARRIER, bio);
 167
 168                 wait_for_completion(&wait);
 169
 170                 if (bio_flagged(bio, BIO_EOPNOTSUPP))
 171                         ret = -EOPNOTSUPP;
 172                 else if (!bio_flagged(bio, BIO_UPTODATE))
 173                         ret = -EIO;
 174                 bio_put(bio);
 175         }
 176         return ret;
 177 }
 178
 179 static int put_ushort(unsigned long arg, unsigned short val)
 180 {
 181         return put_user(val, (unsigned short __user *)arg);
 182 }
 183
 184 static int put_int(unsigned long arg, int val)
 185 {
 186         return put_user(val, (int __user *)arg);
 187 }
 188
 189 static int put_long(unsigned long arg, long val)
 190 {
 191         return put_user(val, (long __user *)arg);
 192 }
 193
 194 static int put_ulong(unsigned long arg, unsigned long val)
 195 {
 196         return put_user(val, (unsigned long __user *)arg);
 197 }
 198
 199 static int put_u64(unsigned long arg, u64 val)
 200 {
 201         return put_user(val, (u64 __user *)arg);
 202 }
 203
 204 int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 205                         unsigned cmd, unsigned long arg)
 206 {
 207         struct gendisk *disk = bdev->bd_disk;
 208         int ret;
 209
 210         if (disk->fops->ioctl)
 211                 return disk->fops->ioctl(bdev, mode, cmd, arg);
 212
 213         if (disk->fops->locked_ioctl) {
 214                 lock_kernel();
 215                 ret = disk->fops->locked_ioctl(bdev, mode, cmd, arg);
 216                 unlock_kernel();
 217                 return ret;
 218         }
 219
 220         return -ENOTTY;
 221 }
 222 /*
 223  * For the record: _GPL here is only because somebody decided to slap it
 224  * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 225  * at all and could be open-coded without any exports by anybody who cares.
 226  */
 227 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 228
 229 /*
 230  * always keep this in sync with compat_blkdev_ioctl() and
 231  * compat_blkdev_locked_ioctl()
 232  */
 233 int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 234                         unsigned long arg)
 235 {
 236         struct gendisk *disk = bdev->bd_disk;
 237         struct backing_dev_info *bdi;
 238         loff_t size;
 239         int ret, n;
 240
 241         switch(cmd) {
 242         case BLKFLSBUF:
 243                 if (!capable(CAP_SYS_ADMIN))
 244                         return -EACCES;
 245
 246                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 247                 /* -EINVAL to handle old uncorrected drivers */
 248                 if (ret != -EINVAL && ret != -ENOTTY)
 249                         return ret;
 250
 251                 lock_kernel();
 252                 fsync_bdev(bdev);
 253                 invalidate_bdev(bdev);
 254                 unlock_kernel();
 255                 return 0;
 256
 257         case BLKROSET:
 258                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 259                 /* -EINVAL to handle old uncorrected drivers */
 260                 if (ret != -EINVAL && ret != -ENOTTY)
 261                         return ret;
 262                 if (!capable(CAP_SYS_ADMIN))
 263                         return -EACCES;
 264                 if (get_user(n, (int __user *)(arg)))
 265                         return -EFAULT;
 266                 lock_kernel();
 267                 set_device_ro(bdev, n);
 268                 unlock_kernel();
 269                 return 0;
 270
 271         case BLKDISCARD: {
 272                 uint64_t range[2];
 273
 274                 if (!(mode & FMODE_WRITE))
 275                         return -EBADF;
 276
 277                 if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 278                         return -EFAULT;
 279
 280                 return blk_ioctl_discard(bdev, range[0], range[1]);
 281         }
 282
 283         case HDIO_GETGEO: {
 284                 struct hd_geometry geo;
 285
 286                 if (!arg)
 287                         return -EINVAL;
 288                 if (!disk->fops->getgeo)
 289                         return -ENOTTY;
 290
 291                 /*
 292                  * We need to set the startsect first, the driver may
 293                  * want to override it.
 294                  */
 295                 geo.start = get_start_sect(bdev);
 296                 ret = disk->fops->getgeo(bdev, &geo);
 297                 if (ret)
 298                         return ret;
 299                 if (copy_to_user((struct hd_geometry __user *)arg, &geo,
 300                                         sizeof(geo)))
 301                         return -EFAULT;
 302                 return 0;
 303         }
 304         case BLKRAGET:
 305         case BLKFRAGET:
 306                 if (!arg)
 307                         return -EINVAL;
 308                 bdi = blk_get_backing_dev_info(bdev);
 309                 if (bdi == NULL)
 310                         return -ENOTTY;
 311                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 312         case BLKROGET:
 313                 return put_int(arg, bdev_read_only(bdev) != 0);
 314         case BLKBSZGET: /* get the logical block size (cf. BLKSSZGET) */
 315                 return put_int(arg, block_size(bdev));
 316         case BLKSSZGET: /* get block device hardware sector size */
 317                 return put_int(arg, bdev_hardsect_size(bdev));
 318         case BLKSECTGET:
 319                 return put_ushort(arg, bdev_get_queue(bdev)->max_sectors);
 320         case BLKRASET:
 321         case BLKFRASET:
 322                 if(!capable(CAP_SYS_ADMIN))
 323                         return -EACCES;
 324                 bdi = blk_get_backing_dev_info(bdev);
 325                 if (bdi == NULL)
 326                         return -ENOTTY;
 327                 lock_kernel();
 328                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 329                 unlock_kernel();
 330                 return 0;
 331         case BLKBSZSET:
 332                 /* set the logical block size */
 333                 if (!capable(CAP_SYS_ADMIN))
 334                         return -EACCES;
 335                 if (!arg)
 336                         return -EINVAL;
 337                 if (get_user(n, (int __user *) arg))
 338                         return -EFAULT;
 339                 if (!(mode & FMODE_EXCL) && bd_claim(bdev, &bdev) < 0)
 340                         return -EBUSY;
 341                 ret = set_blocksize(bdev, n);
 342                 if (!(mode & FMODE_EXCL))
 343                         bd_release(bdev);
 344                 return ret;
 345         case BLKPG:
 346                 lock_kernel();
 347                 ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 348                 unlock_kernel();
 349                 break;
 350         case BLKRRPART:
 351                 lock_kernel();
 352                 ret = blkdev_reread_part(bdev);
 353                 unlock_kernel();
 354                 break;
 355         case BLKGETSIZE:
 356                 size = bdev->bd_inode->i_size;
 357                 if ((size >> 9) > ~0UL)
 358                         return -EFBIG;
 359                 return put_ulong(arg, size >> 9);
 360         case BLKGETSIZE64:
 361                 return put_u64(arg, bdev->bd_inode->i_size);
 362         case BLKTRACESTART:
 363         case BLKTRACESTOP:
 364         case BLKTRACESETUP:
 365         case BLKTRACETEARDOWN:
 366                 lock_kernel();
 367                 ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
 368                 unlock_kernel();
 369                 break;
 370         default:
 371                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 372         }
 373         return ret;
 374 }
 375 EXPORT_SYMBOL_GPL(blkdev_ioctl);