+static int ioctl_fsfreeze(struct file *filp)
+{
+ struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ /* If filesystem doesn't support freeze feature, return. */
+ 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;
+}
+
+static int ioctl_fsthaw(struct file *filp)
+{
+ struct super_block *sb = filp->f_path.dentry->d_inode->i_sb;
+
+ 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);
+}
+