block/ioctl.c

   1 #include <linux/capability.h>
   2 #include <linux/blkdev.h>
   3 #include <linux/gfp.h>
   4 #include <linux/blkpg.h>
   5 #include <linux/hdreg.h>
   6 #include <linux/backing-dev.h>
   7 #include <linux/buffer_head.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, NULL);
  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, int secure)
 117 {
 118         unsigned long flags = 0;
 119
 120         if (start & 511)
 121                 return -EINVAL;
 122         if (len & 511)
 123                 return -EINVAL;
 124         start >>= 9;
 125         len >>= 9;
 126
 127         if (start + len > (i_size_read(bdev->bd_inode) >> 9))
 128                 return -EINVAL;
 129         if (secure)
 130                 flags |= BLKDEV_DISCARD_SECURE;
 131         return blkdev_issue_discard(bdev, start, len, GFP_KERNEL, flags);
 132 }
 133
 134 static int put_ushort(unsigned long arg, unsigned short val)
 135 {
 136         return put_user(val, (unsigned short __user *)arg);
 137 }
 138
 139 static int put_int(unsigned long arg, int val)
 140 {
 141         return put_user(val, (int __user *)arg);
 142 }
 143
 144 static int put_uint(unsigned long arg, unsigned int val)
 145 {
 146         return put_user(val, (unsigned int __user *)arg);
 147 }
 148
 149 static int put_long(unsigned long arg, long val)
 150 {
 151         return put_user(val, (long __user *)arg);
 152 }
 153
 154 static int put_ulong(unsigned long arg, unsigned long val)
 155 {
 156         return put_user(val, (unsigned long __user *)arg);
 157 }
 158
 159 static int put_u64(unsigned long arg, u64 val)
 160 {
 161         return put_user(val, (u64 __user *)arg);
 162 }
 163
 164 int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 165                         unsigned cmd, unsigned long arg)
 166 {
 167         struct gendisk *disk = bdev->bd_disk;
 168
 169         if (disk->fops->ioctl)
 170                 return disk->fops->ioctl(bdev, mode, cmd, arg);
 171
 172         return -ENOTTY;
 173 }
 174 /*
 175  * For the record: _GPL here is only because somebody decided to slap it
 176  * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 177  * at all and could be open-coded without any exports by anybody who cares.
 178  */
 179 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 180
 181 /*
 182  * always keep this in sync with compat_blkdev_ioctl()
 183  */
 184 int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 185                         unsigned long arg)
 186 {
 187         struct gendisk *disk = bdev->bd_disk;
 188         struct backing_dev_info *bdi;
 189         loff_t size;
 190         int ret, n;
 191
 192         switch(cmd) {
 193         case BLKFLSBUF:
 194                 if (!capable(CAP_SYS_ADMIN))
 195                         return -EACCES;
 196
 197                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 198                 /* -EINVAL to handle old uncorrected drivers */
 199                 if (ret != -EINVAL && ret != -ENOTTY)
 200                         return ret;
 201
 202                 fsync_bdev(bdev);
 203                 invalidate_bdev(bdev);
 204                 return 0;
 205
 206         case BLKROSET:
 207                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 208                 /* -EINVAL to handle old uncorrected drivers */
 209                 if (ret != -EINVAL && ret != -ENOTTY)
 210                         return ret;
 211                 if (!capable(CAP_SYS_ADMIN))
 212                         return -EACCES;
 213                 if (get_user(n, (int __user *)(arg)))
 214                         return -EFAULT;
 215                 set_device_ro(bdev, n);
 216                 return 0;
 217
 218         case BLKDISCARD:
 219         case BLKSECDISCARD: {
 220                 uint64_t range[2];
 221
 222                 if (!(mode & FMODE_WRITE))
 223                         return -EBADF;
 224
 225                 if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 226                         return -EFAULT;
 227
 228                 return blk_ioctl_discard(bdev, range[0], range[1],
 229                                          cmd == BLKSECDISCARD);
 230         }
 231
 232         case HDIO_GETGEO: {
 233                 struct hd_geometry geo;
 234
 235                 if (!arg)
 236                         return -EINVAL;
 237                 if (!disk->fops->getgeo)
 238                         return -ENOTTY;
 239
 240                 /*
 241                  * We need to set the startsect first, the driver may
 242                  * want to override it.
 243                  */
 244                 memset(&geo, 0, sizeof(geo));
 245                 geo.start = get_start_sect(bdev);
 246                 ret = disk->fops->getgeo(bdev, &geo);
 247                 if (ret)
 248                         return ret;
 249                 if (copy_to_user((struct hd_geometry __user *)arg, &geo,
 250                                         sizeof(geo)))
 251                         return -EFAULT;
 252                 return 0;
 253         }
 254         case BLKRAGET:
 255         case BLKFRAGET:
 256                 if (!arg)
 257                         return -EINVAL;
 258                 bdi = blk_get_backing_dev_info(bdev);
 259                 if (bdi == NULL)
 260                         return -ENOTTY;
 261                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 262         case BLKROGET:
 263                 return put_int(arg, bdev_read_only(bdev) != 0);
 264         case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
 265                 return put_int(arg, block_size(bdev));
 266         case BLKSSZGET: /* get block device logical block size */
 267                 return put_int(arg, bdev_logical_block_size(bdev));
 268         case BLKPBSZGET: /* get block device physical block size */
 269                 return put_uint(arg, bdev_physical_block_size(bdev));
 270         case BLKIOMIN:
 271                 return put_uint(arg, bdev_io_min(bdev));
 272         case BLKIOOPT:
 273                 return put_uint(arg, bdev_io_opt(bdev));
 274         case BLKALIGNOFF:
 275                 return put_int(arg, bdev_alignment_offset(bdev));
 276         case BLKDISCARDZEROES:
 277                 return put_uint(arg, bdev_discard_zeroes_data(bdev));
 278         case BLKSECTGET:
 279                 return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev)));
 280         case BLKRASET:
 281         case BLKFRASET:
 282                 if(!capable(CAP_SYS_ADMIN))
 283                         return -EACCES;
 284                 bdi = blk_get_backing_dev_info(bdev);
 285                 if (bdi == NULL)
 286                         return -ENOTTY;
 287                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 288                 return 0;
 289         case BLKBSZSET:
 290                 /* set the logical block size */
 291                 if (!capable(CAP_SYS_ADMIN))
 292                         return -EACCES;
 293                 if (!arg)
 294                         return -EINVAL;
 295                 if (get_user(n, (int __user *) arg))
 296                         return -EFAULT;
 297                 if (!(mode & FMODE_EXCL)) {
 298                         bdgrab(bdev);
 299                         if (blkdev_get(bdev, mode | FMODE_EXCL, &bdev) < 0)
 300                                 return -EBUSY;
 301                 }
 302                 ret = set_blocksize(bdev, n);
 303                 if (!(mode & FMODE_EXCL))
 304                         blkdev_put(bdev, mode | FMODE_EXCL);
 305                 return ret;
 306         case BLKPG:
 307                 ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 308                 break;
 309         case BLKRRPART:
 310                 ret = blkdev_reread_part(bdev);
 311                 break;
 312         case BLKGETSIZE:
 313                 size = i_size_read(bdev->bd_inode);
 314                 if ((size >> 9) > ~0UL)
 315                         return -EFBIG;
 316                 return put_ulong(arg, size >> 9);
 317         case BLKGETSIZE64:
 318                 return put_u64(arg, i_size_read(bdev->bd_inode));
 319         case BLKTRACESTART:
 320         case BLKTRACESTOP:
 321         case BLKTRACESETUP:
 322         case BLKTRACETEARDOWN:
 323                 ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
 324                 break;
 325         default:
 326                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 327         }
 328         return ret;
 329 }
 330 EXPORT_SYMBOL_GPL(blkdev_ioctl);