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/smp_lock.h>
   9 #include <linux/blktrace_api.h>
  10 #include <asm/uaccess.h>
  11
  12 static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
  13 {
  14         struct block_device *bdevp;
  15         struct gendisk *disk;
  16         struct hd_struct *part;
  17         struct blkpg_ioctl_arg a;
  18         struct blkpg_partition p;
  19         struct disk_part_iter piter;
  20         long long start, length;
  21         int partno;
  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                         part = add_partition(disk, partno, start, length,
  65                                              ADDPART_FLAG_NONE);
  66                         mutex_unlock(&bdev->bd_mutex);
  67                         return IS_ERR(part) ? PTR_ERR(part) : 0;
  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 int blk_ioctl_discard(struct block_device *bdev, uint64_t start,
 117                              uint64_t len)
 118 {
 119         if (start & 511)
 120                 return -EINVAL;
 121         if (len & 511)
 122                 return -EINVAL;
 123         start >>= 9;
 124         len >>= 9;
 125
 126         if (start + len > (bdev->bd_inode->i_size >> 9))
 127                 return -EINVAL;
 128         return blkdev_issue_discard(bdev, start, len, GFP_KERNEL,
 129                                     DISCARD_FL_WAIT);
 130 }
 131
 132 static int put_ushort(unsigned long arg, unsigned short val)
 133 {
 134         return put_user(val, (unsigned short __user *)arg);
 135 }
 136
 137 static int put_int(unsigned long arg, int val)
 138 {
 139         return put_user(val, (int __user *)arg);
 140 }
 141
 142 static int put_uint(unsigned long arg, unsigned int val)
 143 {
 144         return put_user(val, (unsigned int __user *)arg);
 145 }
 146
 147 static int put_long(unsigned long arg, long val)
 148 {
 149         return put_user(val, (long __user *)arg);
 150 }
 151
 152 static int put_ulong(unsigned long arg, unsigned long val)
 153 {
 154         return put_user(val, (unsigned long __user *)arg);
 155 }
 156
 157 static int put_u64(unsigned long arg, u64 val)
 158 {
 159         return put_user(val, (u64 __user *)arg);
 160 }
 161
 162 int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 163                         unsigned cmd, unsigned long arg)
 164 {
 165         struct gendisk *disk = bdev->bd_disk;
 166         int ret;
 167
 168         if (disk->fops->ioctl)
 169                 return disk->fops->ioctl(bdev, mode, cmd, arg);
 170
 171         if (disk->fops->locked_ioctl) {
 172                 lock_kernel();
 173                 ret = disk->fops->locked_ioctl(bdev, mode, cmd, arg);
 174                 unlock_kernel();
 175                 return ret;
 176         }
 177
 178         return -ENOTTY;
 179 }
 180 /*
 181  * For the record: _GPL here is only because somebody decided to slap it
 182  * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 183  * at all and could be open-coded without any exports by anybody who cares.
 184  */
 185 EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 186
 187 /*
 188  * always keep this in sync with compat_blkdev_ioctl() and
 189  * compat_blkdev_locked_ioctl()
 190  */
 191 int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 192                         unsigned long arg)
 193 {
 194         struct gendisk *disk = bdev->bd_disk;
 195         struct backing_dev_info *bdi;
 196         loff_t size;
 197         int ret, n;
 198
 199         switch(cmd) {
 200         case BLKFLSBUF:
 201                 if (!capable(CAP_SYS_ADMIN))
 202                         return -EACCES;
 203
 204                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 205                 /* -EINVAL to handle old uncorrected drivers */
 206                 if (ret != -EINVAL && ret != -ENOTTY)
 207                         return ret;
 208
 209                 lock_kernel();
 210                 fsync_bdev(bdev);
 211                 invalidate_bdev(bdev);
 212                 unlock_kernel();
 213                 return 0;
 214
 215         case BLKROSET:
 216                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 217                 /* -EINVAL to handle old uncorrected drivers */
 218                 if (ret != -EINVAL && ret != -ENOTTY)
 219                         return ret;
 220                 if (!capable(CAP_SYS_ADMIN))
 221                         return -EACCES;
 222                 if (get_user(n, (int __user *)(arg)))
 223                         return -EFAULT;
 224                 lock_kernel();
 225                 set_device_ro(bdev, n);
 226                 unlock_kernel();
 227                 return 0;
 228
 229         case BLKDISCARD: {
 230                 uint64_t range[2];
 231
 232                 if (!(mode & FMODE_WRITE))
 233                         return -EBADF;
 234
 235                 if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 236                         return -EFAULT;
 237
 238                 return blk_ioctl_discard(bdev, range[0], range[1]);
 239         }
 240
 241         case HDIO_GETGEO: {
 242                 struct hd_geometry geo;
 243
 244                 if (!arg)
 245                         return -EINVAL;
 246                 if (!disk->fops->getgeo)
 247                         return -ENOTTY;
 248
 249                 /*
 250                  * We need to set the startsect first, the driver may
 251                  * want to override it.
 252                  */
 253                 geo.start = get_start_sect(bdev);
 254                 ret = disk->fops->getgeo(bdev, &geo);
 255                 if (ret)
 256                         return ret;
 257                 if (copy_to_user((struct hd_geometry __user *)arg, &geo,
 258                                         sizeof(geo)))
 259                         return -EFAULT;
 260                 return 0;
 261         }
 262         case BLKRAGET:
 263         case BLKFRAGET:
 264                 if (!arg)
 265                         return -EINVAL;
 266                 bdi = blk_get_backing_dev_info(bdev);
 267                 if (bdi == NULL)
 268                         return -ENOTTY;
 269                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 270         case BLKROGET:
 271                 return put_int(arg, bdev_read_only(bdev) != 0);
 272         case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
 273                 return put_int(arg, block_size(bdev));
 274         case BLKSSZGET: /* get block device logical block size */
 275                 return put_int(arg, bdev_logical_block_size(bdev));
 276         case BLKPBSZGET: /* get block device physical block size */
 277                 return put_uint(arg, bdev_physical_block_size(bdev));
 278         case BLKIOMIN:
 279                 return put_uint(arg, bdev_io_min(bdev));
 280         case BLKIOOPT:
 281                 return put_uint(arg, bdev_io_opt(bdev));
 282         case BLKALIGNOFF:
 283                 return put_int(arg, bdev_alignment_offset(bdev));
 284         case BLKDISCARDZEROES:
 285                 return put_uint(arg, bdev_discard_zeroes_data(bdev));
 286         case BLKSECTGET:
 287                 return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev)));
 288         case BLKRASET:
 289         case BLKFRASET:
 290                 if(!capable(CAP_SYS_ADMIN))
 291                         return -EACCES;
 292                 bdi = blk_get_backing_dev_info(bdev);
 293                 if (bdi == NULL)
 294                         return -ENOTTY;
 295                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 296                 return 0;
 297         case BLKBSZSET:
 298                 /* set the logical block size */
 299                 if (!capable(CAP_SYS_ADMIN))
 300                         return -EACCES;
 301                 if (!arg)
 302                         return -EINVAL;
 303                 if (get_user(n, (int __user *) arg))
 304                         return -EFAULT;
 305                 if (!(mode & FMODE_EXCL) && bd_claim(bdev, &bdev) < 0)
 306                         return -EBUSY;
 307                 ret = set_blocksize(bdev, n);
 308                 if (!(mode & FMODE_EXCL))
 309                         bd_release(bdev);
 310                 return ret;
 311         case BLKPG:
 312                 lock_kernel();
 313                 ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 314                 unlock_kernel();
 315                 break;
 316         case BLKRRPART:
 317                 lock_kernel();
 318                 ret = blkdev_reread_part(bdev);
 319                 unlock_kernel();
 320                 break;
 321         case BLKGETSIZE:
 322                 size = bdev->bd_inode->i_size;
 323                 if ((size >> 9) > ~0UL)
 324                         return -EFBIG;
 325                 return put_ulong(arg, size >> 9);
 326         case BLKGETSIZE64:
 327                 return put_u64(arg, bdev->bd_inode->i_size);
 328         case BLKTRACESTART:
 329         case BLKTRACESTOP:
 330         case BLKTRACESETUP:
 331         case BLKTRACETEARDOWN:
 332                 lock_kernel();
 333                 ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
 334                 unlock_kernel();
 335                 break;
 336         default:
 337                 ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 338         }
 339         return ret;
 340 }
 341 EXPORT_SYMBOL_GPL(blkdev_ioctl);