linux/block/ioctl.c
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   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
  11static 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
  99static 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
 115static 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
 125static 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                if (!bio)
 150                        return -ENOMEM;
 151
 152                bio->bi_end_io = blk_ioc_discard_endio;
 153                bio->bi_bdev = bdev;
 154                bio->bi_private = &wait;
 155                bio->bi_sector = start;
 156
 157                if (len > q->max_hw_sectors) {
 158                        bio->bi_size = q->max_hw_sectors << 9;
 159                        len -= q->max_hw_sectors;
 160                        start += q->max_hw_sectors;
 161                } else {
 162                        bio->bi_size = len << 9;
 163                        len = 0;
 164                }
 165                submit_bio(DISCARD_NOBARRIER, bio);
 166
 167                wait_for_completion(&wait);
 168
 169                if (bio_flagged(bio, BIO_EOPNOTSUPP))
 170                        ret = -EOPNOTSUPP;
 171                else if (!bio_flagged(bio, BIO_UPTODATE))
 172                        ret = -EIO;
 173                bio_put(bio);
 174        }
 175        return ret;
 176}
 177
 178static int put_ushort(unsigned long arg, unsigned short val)
 179{
 180        return put_user(val, (unsigned short __user *)arg);
 181}
 182
 183static int put_int(unsigned long arg, int val)
 184{
 185        return put_user(val, (int __user *)arg);
 186}
 187
 188static int put_long(unsigned long arg, long val)
 189{
 190        return put_user(val, (long __user *)arg);
 191}
 192
 193static int put_ulong(unsigned long arg, unsigned long val)
 194{
 195        return put_user(val, (unsigned long __user *)arg);
 196}
 197
 198static int put_u64(unsigned long arg, u64 val)
 199{
 200        return put_user(val, (u64 __user *)arg);
 201}
 202
 203int __blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 204                        unsigned cmd, unsigned long arg)
 205{
 206        struct gendisk *disk = bdev->bd_disk;
 207        int ret;
 208
 209        if (disk->fops->ioctl)
 210                return disk->fops->ioctl(bdev, mode, cmd, arg);
 211
 212        if (disk->fops->locked_ioctl) {
 213                lock_kernel();
 214                ret = disk->fops->locked_ioctl(bdev, mode, cmd, arg);
 215                unlock_kernel();
 216                return ret;
 217        }
 218
 219        return -ENOTTY;
 220}
 221/*
 222 * For the record: _GPL here is only because somebody decided to slap it
 223 * on the previous export.  Sheer idiocy, since it wasn't copyrightable
 224 * at all and could be open-coded without any exports by anybody who cares.
 225 */
 226EXPORT_SYMBOL_GPL(__blkdev_driver_ioctl);
 227
 228/*
 229 * always keep this in sync with compat_blkdev_ioctl() and
 230 * compat_blkdev_locked_ioctl()
 231 */
 232int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 233                        unsigned long arg)
 234{
 235        struct gendisk *disk = bdev->bd_disk;
 236        struct backing_dev_info *bdi;
 237        loff_t size;
 238        int ret, n;
 239
 240        switch(cmd) {
 241        case BLKFLSBUF:
 242                if (!capable(CAP_SYS_ADMIN))
 243                        return -EACCES;
 244
 245                ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 246                /* -EINVAL to handle old uncorrected drivers */
 247                if (ret != -EINVAL && ret != -ENOTTY)
 248                        return ret;
 249
 250                lock_kernel();
 251                fsync_bdev(bdev);
 252                invalidate_bdev(bdev);
 253                unlock_kernel();
 254                return 0;
 255
 256        case BLKROSET:
 257                ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 258                /* -EINVAL to handle old uncorrected drivers */
 259                if (ret != -EINVAL && ret != -ENOTTY)
 260                        return ret;
 261                if (!capable(CAP_SYS_ADMIN))
 262                        return -EACCES;
 263                if (get_user(n, (int __user *)(arg)))
 264                        return -EFAULT;
 265                lock_kernel();
 266                set_device_ro(bdev, n);
 267                unlock_kernel();
 268                return 0;
 269
 270        case BLKDISCARD: {
 271                uint64_t range[2];
 272
 273                if (!(mode & FMODE_WRITE))
 274                        return -EBADF;
 275
 276                if (copy_from_user(range, (void __user *)arg, sizeof(range)))
 277                        return -EFAULT;
 278
 279                return blk_ioctl_discard(bdev, range[0], range[1]);
 280        }
 281
 282        case HDIO_GETGEO: {
 283                struct hd_geometry geo;
 284
 285                if (!arg)
 286                        return -EINVAL;
 287                if (!disk->fops->getgeo)
 288                        return -ENOTTY;
 289
 290                /*
 291                 * We need to set the startsect first, the driver may
 292                 * want to override it.
 293                 */
 294                geo.start = get_start_sect(bdev);
 295                ret = disk->fops->getgeo(bdev, &geo);
 296                if (ret)
 297                        return ret;
 298                if (copy_to_user((struct hd_geometry __user *)arg, &geo,
 299                                        sizeof(geo)))
 300                        return -EFAULT;
 301                return 0;
 302        }
 303        case BLKRAGET:
 304        case BLKFRAGET:
 305                if (!arg)
 306                        return -EINVAL;
 307                bdi = blk_get_backing_dev_info(bdev);
 308                if (bdi == NULL)
 309                        return -ENOTTY;
 310                return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
 311        case BLKROGET:
 312                return put_int(arg, bdev_read_only(bdev) != 0);
 313        case BLKBSZGET: /* get the logical block size (cf. BLKSSZGET) */
 314                return put_int(arg, block_size(bdev));
 315        case BLKSSZGET: /* get block device hardware sector size */
 316                return put_int(arg, bdev_hardsect_size(bdev));
 317        case BLKSECTGET:
 318                return put_ushort(arg, bdev_get_queue(bdev)->max_sectors);
 319        case BLKRASET:
 320        case BLKFRASET:
 321                if(!capable(CAP_SYS_ADMIN))
 322                        return -EACCES;
 323                bdi = blk_get_backing_dev_info(bdev);
 324                if (bdi == NULL)
 325                        return -ENOTTY;
 326                lock_kernel();
 327                bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
 328                unlock_kernel();
 329                return 0;
 330        case BLKBSZSET:
 331                /* set the logical block size */
 332                if (!capable(CAP_SYS_ADMIN))
 333                        return -EACCES;
 334                if (!arg)
 335                        return -EINVAL;
 336                if (get_user(n, (int __user *) arg))
 337                        return -EFAULT;
 338                if (!(mode & FMODE_EXCL) && bd_claim(bdev, &bdev) < 0)
 339                        return -EBUSY;
 340                ret = set_blocksize(bdev, n);
 341                if (!(mode & FMODE_EXCL))
 342                        bd_release(bdev);
 343                return ret;
 344        case BLKPG:
 345                lock_kernel();
 346                ret = blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
 347                unlock_kernel();
 348                break;
 349        case BLKRRPART:
 350                lock_kernel();
 351                ret = blkdev_reread_part(bdev);
 352                unlock_kernel();
 353                break;
 354        case BLKGETSIZE:
 355                size = bdev->bd_inode->i_size;
 356                if ((size >> 9) > ~0UL)
 357                        return -EFBIG;
 358                return put_ulong(arg, size >> 9);
 359        case BLKGETSIZE64:
 360                return put_u64(arg, bdev->bd_inode->i_size);
 361        case BLKTRACESTART:
 362        case BLKTRACESTOP:
 363        case BLKTRACESETUP:
 364        case BLKTRACETEARDOWN:
 365                lock_kernel();
 366                ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
 367                unlock_kernel();
 368                break;
 369        default:
 370                ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
 371        }
 372        return ret;
 373}
 374EXPORT_SYMBOL_GPL(blkdev_ioctl);
 375