diff options
| -rw-r--r-- | drivers/block/loop.c | 30 | ||||
| -rw-r--r-- | include/linux/loop.h | 1 |
2 files changed, 31 insertions, 0 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 2621ed2ce6d2..40b17d3b55a1 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1192,6 +1192,30 @@ loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) { return err; } +static int loop_set_capacity(struct loop_device *lo, struct block_device *bdev) +{ + int err; + sector_t sec; + loff_t sz; + + err = -ENXIO; + if (unlikely(lo->lo_state != Lo_bound)) + goto out; + err = figure_loop_size(lo); + if (unlikely(err)) + goto out; + sec = get_capacity(lo->lo_disk); + /* the width of sector_t may be narrow for bit-shift */ + sz = sec; + sz <<= 9; + mutex_lock(&bdev->bd_mutex); + bd_set_size(bdev, sz); + mutex_unlock(&bdev->bd_mutex); + + out: + return err; +} + static int lo_ioctl(struct block_device *bdev, fmode_t mode, unsigned int cmd, unsigned long arg) { @@ -1224,6 +1248,11 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode, case LOOP_GET_STATUS64: err = loop_get_status64(lo, (struct loop_info64 __user *) arg); break; + case LOOP_SET_CAPACITY: + err = -EPERM; + if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) + err = loop_set_capacity(lo, bdev); + break; default: err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL; } @@ -1371,6 +1400,7 @@ static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode, lo, (struct compat_loop_info __user *) arg); mutex_unlock(&lo->lo_ctl_mutex); break; + case LOOP_SET_CAPACITY: case LOOP_CLR_FD: case LOOP_GET_STATUS64: case LOOP_SET_STATUS64: diff --git a/include/linux/loop.h b/include/linux/loop.h index 6ffd6db5bb0d..40725447f5e0 100644 --- a/include/linux/loop.h +++ b/include/linux/loop.h @@ -160,5 +160,6 @@ int loop_unregister_transfer(int number); #define LOOP_SET_STATUS64 0x4C04 #define LOOP_GET_STATUS64 0x4C05 #define LOOP_CHANGE_FD 0x4C06 +#define LOOP_SET_CAPACITY 0x4C07 #endif |