diff --git a/fs/block_dev.c b/fs/block_dev.c
index 39cb6591d37d..1aba036dcabf 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -245,38 +245,14 @@ struct super_block *freeze_bdev(struct block_device *bdev)
 	sb = get_active_super(bdev);
 	if (!sb)
 		goto out;
-	down_write(&sb->s_umount);
-	if (sb->s_flags & MS_RDONLY) {
-		sb->s_frozen = SB_FREEZE_TRANS;
-		up_write(&sb->s_umount);
+	error = freeze_super(sb);
+	if (error) {
+		deactivate_super(sb);
+		bdev->bd_fsfreeze_count--;
 		mutex_unlock(&bdev->bd_fsfreeze_mutex);
-		return sb;
+		return ERR_PTR(error);
 	}
-
-	sb->s_frozen = SB_FREEZE_WRITE;
-	smp_wmb();
-
-	sync_filesystem(sb);
-
-	sb->s_frozen = SB_FREEZE_TRANS;
-	smp_wmb();
-
-	sync_blockdev(sb->s_bdev);
-
-	if (sb->s_op->freeze_fs) {
-		error = sb->s_op->freeze_fs(sb);
-		if (error) {
-			printk(KERN_ERR
-				"VFS:Filesystem freeze failed\n");
-			sb->s_frozen = SB_UNFROZEN;
-			deactivate_locked_super(sb);
-			bdev->bd_fsfreeze_count--;
-			mutex_unlock(&bdev->bd_fsfreeze_mutex);
-			return ERR_PTR(error);
-		}
-	}
-	up_write(&sb->s_umount);
-
+	deactivate_super(sb);
  out:
 	sync_blockdev(bdev);
 	mutex_unlock(&bdev->bd_fsfreeze_mutex);
@@ -297,40 +273,22 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb)
 
 	mutex_lock(&bdev->bd_fsfreeze_mutex);
 	if (!bdev->bd_fsfreeze_count)
-		goto out_unlock;
+		goto out;
 
 	error = 0;
 	if (--bdev->bd_fsfreeze_count > 0)
-		goto out_unlock;
+		goto out;
 
 	if (!sb)
-		goto out_unlock;
+		goto out;
 
-	BUG_ON(sb->s_bdev != bdev);
-	down_write(&sb->s_umount);
-	if (sb->s_flags & MS_RDONLY)
-		goto out_unfrozen;
-
-	if (sb->s_op->unfreeze_fs) {
-		error = sb->s_op->unfreeze_fs(sb);
-		if (error) {
-			printk(KERN_ERR
-				"VFS:Filesystem thaw failed\n");
-			sb->s_frozen = SB_FREEZE_TRANS;
-			bdev->bd_fsfreeze_count++;
-			mutex_unlock(&bdev->bd_fsfreeze_mutex);
-			return error;
-		}
+	error = thaw_super(sb);
+	if (error) {
+		bdev->bd_fsfreeze_count++;
+		mutex_unlock(&bdev->bd_fsfreeze_mutex);
+		return error;
 	}
-
-out_unfrozen:
-	sb->s_frozen = SB_UNFROZEN;
-	smp_wmb();
-	wake_up(&sb->s_wait_unfrozen);
-
-	if (sb)
-		deactivate_locked_super(sb);
-out_unlock:
+out:
 	mutex_unlock(&bdev->bd_fsfreeze_mutex);
 	return 0;
 }
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 7faefb4da939..2d140a713861 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -525,15 +525,8 @@ static int ioctl_fsfreeze(struct file *filp)
 	if (sb->s_op->freeze_fs == NULL)
 		return -EOPNOTSUPP;
 
-	/* If a blockdevice-backed filesystem isn't specified, return. */
-	if (sb->s_bdev == NULL)
-		return -EINVAL;
-
 	/* Freeze */
-	sb = freeze_bdev(sb->s_bdev);
-	if (IS_ERR(sb))
-		return PTR_ERR(sb);
-	return 0;
+	return freeze_super(sb);
 }
 
 static int ioctl_fsthaw(struct file *filp)
@@ -543,12 +536,8 @@ static int ioctl_fsthaw(struct file *filp)
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
-	/* If a blockdevice-backed filesystem isn't specified, return EINVAL. */
-	if (sb->s_bdev == NULL)
-		return -EINVAL;
-
 	/* Thaw */
-	return thaw_bdev(sb->s_bdev, sb);
+	return thaw_super(sb);
 }
 
 /*
diff --git a/fs/super.c b/fs/super.c
index c248ac6a1a21..89afca5055ab 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -944,6 +944,96 @@ out:
 
 EXPORT_SYMBOL_GPL(vfs_kern_mount);
 
+/**
+ * freeze_super -- lock the filesystem and force it into a consistent state
+ * @super: the super to lock
+ *
+ * Syncs the super to make sure the filesystem is consistent and calls the fs's
+ * freeze_fs.  Subsequent calls to this without first thawing the fs will return
+ * -EBUSY.
+ */
+int freeze_super(struct super_block *sb)
+{
+	int ret;
+
+	atomic_inc(&sb->s_active);
+	down_write(&sb->s_umount);
+	if (sb->s_frozen) {
+		deactivate_locked_super(sb);
+		return -EBUSY;
+	}
+
+	if (sb->s_flags & MS_RDONLY) {
+		sb->s_frozen = SB_FREEZE_TRANS;
+		smp_wmb();
+		up_write(&sb->s_umount);
+		return 0;
+	}
+
+	sb->s_frozen = SB_FREEZE_WRITE;
+	smp_wmb();
+
+	sync_filesystem(sb);
+
+	sb->s_frozen = SB_FREEZE_TRANS;
+	smp_wmb();
+
+	sync_blockdev(sb->s_bdev);
+	if (sb->s_op->freeze_fs) {
+		ret = sb->s_op->freeze_fs(sb);
+		if (ret) {
+			printk(KERN_ERR
+				"VFS:Filesystem freeze failed\n");
+			sb->s_frozen = SB_UNFROZEN;
+			deactivate_locked_super(sb);
+			return ret;
+		}
+	}
+	up_write(&sb->s_umount);
+	return 0;
+}
+EXPORT_SYMBOL(freeze_super);
+
+/**
+ * thaw_super -- unlock filesystem
+ * @sb: the super to thaw
+ *
+ * Unlocks the filesystem and marks it writeable again after freeze_super().
+ */
+int thaw_super(struct super_block *sb)
+{
+	int error;
+
+	down_write(&sb->s_umount);
+	if (sb->s_frozen == SB_UNFROZEN) {
+		up_write(&sb->s_umount);
+		return -EINVAL;
+	}
+
+	if (sb->s_flags & MS_RDONLY)
+		goto out;
+
+	if (sb->s_op->unfreeze_fs) {
+		error = sb->s_op->unfreeze_fs(sb);
+		if (error) {
+			printk(KERN_ERR
+				"VFS:Filesystem thaw failed\n");
+			sb->s_frozen = SB_FREEZE_TRANS;
+			up_write(&sb->s_umount);
+			return error;
+		}
+	}
+
+out:
+	sb->s_frozen = SB_UNFROZEN;
+	smp_wmb();
+	wake_up(&sb->s_wait_unfrozen);
+	deactivate_locked_super(sb);
+
+	return 0;
+}
+EXPORT_SYMBOL(thaw_super);
+
 static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
 {
 	int err;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index eeb04ba17b63..d51256bc6328 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1797,6 +1797,8 @@ extern void drop_collected_mounts(struct vfsmount *);
 extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
 			  struct vfsmount *);
 extern int vfs_statfs(struct dentry *, struct kstatfs *);
+extern int freeze_super(struct super_block *super);
+extern int thaw_super(struct super_block *super);
 
 extern int current_umask(void);