---

yaml
---
r: 139179
b: refs/heads/master
c: 53d6660
h: refs/heads/master
i:
  139177: 73a60ea
  139175: ec81b19
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 65bd6a9bc7be3f5841dad12f77ce4b3210bd82c5
+refs/heads/master: 53d6660836f233df66490707365ab177e5fb2bb4

trunk/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:

trunk/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