drivers/block/ioctl.c

   1 #include <linux/sched.h>                /* for capable() */
   2 #include <linux/blkdev.h>
   3 #include <linux/blkpg.h>
   4 #include <linux/backing-dev.h>
   5 #include <linux/buffer_head.h>
   6 #include <asm/uaccess.h>
   7
   8 static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg *arg)
   9 {
  10         struct block_device *bdevp;
  11         struct gendisk *disk;
  12         struct blkpg_ioctl_arg a;
  13         struct blkpg_partition p;
  14         long long start, length;
  15         int part;
  16         int i;
  17
  18         if (!capable(CAP_SYS_ADMIN))
  19                 return -EACCES;
  20         if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
  21                 return -EFAULT;
  22         if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
  23                 return -EFAULT;
  24         disk = bdev->bd_disk;
  25         if (bdev != bdev->bd_contains)
  26                 return -EINVAL;
  27         part = p.pno;
  28         if (part <= 0 || part >= disk->minors)
  29                 return -EINVAL;
  30         switch (a.op) {
  31                 case BLKPG_ADD_PARTITION:
  32                         start = p.start >> 9;
  33                         length = p.length >> 9;
  34                         /* check for fit in a hd_struct */
  35                         if (sizeof(sector_t) == sizeof(long) &&
  36                             sizeof(long long) > sizeof(long)) {
  37                                 long pstart = start, plength = length;
  38                                 if (pstart != start || plength != length
  39                                     || pstart < 0 || plength < 0)
  40                                         return -EINVAL;
  41                         }
  42                         /* partition number in use? */
  43                         down(&bdev->bd_sem);
  44                         if (disk->part[part - 1]) {
  45                                 up(&bdev->bd_sem);
  46                                 return -EBUSY;
  47                         }
  48                         /* overlap? */
  49                         for (i = 0; i < disk->minors - 1; i++) {
  50                                 struct hd_struct *s = disk->part[i];
  51
  52                                 if (!s)
  53                                         continue;
  54                                 if (!(start+length <= s->start_sect ||
  55                                       start >= s->start_sect + s->nr_sects)) {
  56                                         up(&bdev->bd_sem);
  57                                         return -EBUSY;
  58                                 }
  59                         }
  60                         /* all seems OK */
  61                         add_partition(disk, part, start, length);
  62                         up(&bdev->bd_sem);
  63                         return 0;
  64                 case BLKPG_DEL_PARTITION:
  65                         if (!disk->part[part-1])
  66                                 return -ENXIO;
  67                         if (disk->part[part - 1]->nr_sects == 0)
  68                                 return -ENXIO;
  69                         bdevp = bdget_disk(disk, part);
  70                         if (!bdevp)
  71                                 return -ENOMEM;
  72                         down(&bdevp->bd_sem);
  73                         if (bdevp->bd_openers) {
  74                                 up(&bdevp->bd_sem);
  75                                 bdput(bdevp);
  76                                 return -EBUSY;
  77                         }
  78                         /* all seems OK */
  79                         fsync_bdev(bdevp);
  80                         invalidate_bdev(bdevp, 0);
  81
  82                         down(&bdev->bd_sem);
  83                         delete_partition(disk, part);
  84                         up(&bdev->bd_sem);
  85                         up(&bdevp->bd_sem);
  86                         bdput(bdevp);
  87
  88                         return 0;
  89                 default:
  90                         return -EINVAL;
  91         }
  92 }
  93
  94 static int blkdev_reread_part(struct block_device *bdev)
  95 {
  96         struct gendisk *disk = bdev->bd_disk;
  97         int res;
  98
  99         if (disk->minors == 1 || bdev != bdev->bd_contains)
 100                 return -EINVAL;
 101         if (!capable(CAP_SYS_ADMIN))
 102                 return -EACCES;
 103         if (down_trylock(&bdev->bd_sem))
 104                 return -EBUSY;
 105         res = rescan_partitions(disk, bdev);
 106         up(&bdev->bd_sem);
 107         return res;
 108 }
 109
 110 static int put_ushort(unsigned long arg, unsigned short val)
 111 {
 112         return put_user(val, (unsigned short *)arg);
 113 }
 114
 115 static int put_int(unsigned long arg, int val)
 116 {
 117         return put_user(val, (int *)arg);
 118 }
 119
 120 static int put_long(unsigned long arg, long val)
 121 {
 122         return put_user(val, (long *)arg);
 123 }
 124
 125 static int put_ulong(unsigned long arg, unsigned long val)
 126 {
 127         return put_user(val, (unsigned long *)arg);
 128 }
 129
 130 static int put_u64(unsigned long arg, u64 val)
 131 {
 132         return put_user(val, (u64 *)arg);
 133 }
 134
 135 int blkdev_ioctl(struct inode *inode, struct file *file, unsigned cmd,
 136                         unsigned long arg)
 137 {
 138         struct block_device *bdev = inode->i_bdev;
 139         struct gendisk *disk = bdev->bd_disk;
 140         struct backing_dev_info *bdi;
 141         int ret, n;
 142
 143         switch (cmd) {
 144         case BLKRAGET:
 145         case BLKFRAGET:
 146                 if (!arg)
 147                         return -EINVAL;
 148                 bdi = blk_get_backing_dev_info(bdev);
 149                 if (bdi == NULL)
 150                         return -ENOTTY;
 151                 return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 152         case BLKROGET:
 153                 return put_int(arg, bdev_read_only(bdev) != 0);
 154         case BLKBSZGET: /* get the logical block size (cf. BLKSSZGET) */
 155                 return put_int(arg, block_size(bdev));
 156         case BLKSSZGET: /* get block device hardware sector size */
 157                 return put_int(arg, bdev_hardsect_size(bdev));
 158         case BLKSECTGET:
 159                 return put_ushort(arg, bdev_get_queue(bdev)->max_sectors);
 160         case BLKRASET:
 161         case BLKFRASET:
 162                 if(!capable(CAP_SYS_ADMIN))
 163                         return -EACCES;
 164                 bdi = blk_get_backing_dev_info(bdev);
 165                 if (bdi == NULL)
 166                         return -ENOTTY;
 167                 bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 168                 return 0;
 169         case BLKBSZSET:
 170                 /* set the logical block size */
 171                 if (!capable(CAP_SYS_ADMIN))
 172                         return -EACCES;
 173                 if (!arg)
 174                         return -EINVAL;
 175                 if (get_user(n, (int *) arg))
 176                         return -EFAULT;
 177                 if (bd_claim(bdev, file) < 0)
 178                         return -EBUSY;
 179                 ret = set_blocksize(bdev, n);
 180                 bd_release(bdev);
 181                 return ret;
 182         case BLKPG:
 183                 return blkpg_ioctl(bdev, (struct blkpg_ioctl_arg *) arg);
 184         case BLKRRPART:
 185                 return blkdev_reread_part(bdev);
 186         case BLKGETSIZE:
 187                 if ((bdev->bd_inode->i_size >> 9) > ~0UL)
 188                         return -EFBIG;
 189                 return put_ulong(arg, bdev->bd_inode->i_size >> 9);
 190         case BLKGETSIZE64:
 191                 return put_u64(arg, bdev->bd_inode->i_size);
 192         case BLKFLSBUF:
 193                 if (!capable(CAP_SYS_ADMIN))
 194                         return -EACCES;
 195                 if (disk->fops->ioctl) {
 196                         ret = disk->fops->ioctl(inode, file, cmd, arg);
 197                         if (ret != -EINVAL)
 198                                 return ret;
 199                 }
 200                 fsync_bdev(bdev);
 201                 invalidate_bdev(bdev, 0);
 202                 return 0;
 203         case BLKROSET:
 204                 if (disk->fops->ioctl) {
 205                         ret = disk->fops->ioctl(inode, file, cmd, arg);
 206                         if (ret != -EINVAL)
 207                                 return ret;
 208                 }
 209                 if (!capable(CAP_SYS_ADMIN))
 210                         return -EACCES;
 211                 if (get_user(n, (int *)(arg)))
 212                         return -EFAULT;
 213                 set_device_ro(bdev, n);
 214                 return 0;
 215         default:
 216                 if (disk->fops->ioctl)
 217                         return disk->fops->ioctl(inode, file, cmd, arg);
 218         }
 219         return -ENOTTY;
 220 }