ext4: wire up new fscrypt ioctls

Wire up the new ioctls for adding and removing fscrypt keys to/from the
filesystem, and the new ioctl for retrieving v2 encryption policies.

The key removal ioctls also required making ext4_drop_inode() call
fscrypt_drop_inode().

For more details see Documentation/filesystems/fscrypt.rst and the
fscrypt patches that added the implementation of these ioctls.

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>

fs/ext4/ioctl.c

@@ -1115,6 +1115,31 @@ resizefs_out:
 	case EXT4_IOC_GET_ENCRYPTION_POLICY:
 		return fscrypt_ioctl_get_policy(filp, (void __user *)arg);
 
+	case FS_IOC_GET_ENCRYPTION_POLICY_EX:
+		if (!ext4_has_feature_encrypt(sb))
+			return -EOPNOTSUPP;
+		return fscrypt_ioctl_get_policy_ex(filp, (void __user *)arg);
+
+	case FS_IOC_ADD_ENCRYPTION_KEY:
+		if (!ext4_has_feature_encrypt(sb))
+			return -EOPNOTSUPP;
+		return fscrypt_ioctl_add_key(filp, (void __user *)arg);
+
+	case FS_IOC_REMOVE_ENCRYPTION_KEY:
+		if (!ext4_has_feature_encrypt(sb))
+			return -EOPNOTSUPP;
+		return fscrypt_ioctl_remove_key(filp, (void __user *)arg);
+
+	case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
+		if (!ext4_has_feature_encrypt(sb))
+			return -EOPNOTSUPP;
+		return fscrypt_ioctl_remove_key_all_users(filp,
+							  (void __user *)arg);
+	case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
+		if (!ext4_has_feature_encrypt(sb))
+			return -EOPNOTSUPP;
+		return fscrypt_ioctl_get_key_status(filp, (void __user *)arg);
+
 	case EXT4_IOC_FSGETXATTR:
 	{
 		struct fsxattr fa;
@@ -1231,6 +1256,11 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case EXT4_IOC_SET_ENCRYPTION_POLICY:
 	case EXT4_IOC_GET_ENCRYPTION_PWSALT:
 	case EXT4_IOC_GET_ENCRYPTION_POLICY:
+	case FS_IOC_GET_ENCRYPTION_POLICY_EX:
+	case FS_IOC_ADD_ENCRYPTION_KEY:
+	case FS_IOC_REMOVE_ENCRYPTION_KEY:
+	case FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS:
+	case FS_IOC_GET_ENCRYPTION_KEY_STATUS:
 	case EXT4_IOC_SHUTDOWN:
 	case FS_IOC_GETFSMAP:
 		break;

fs/ext4/super.c

@@ -1107,6 +1107,9 @@ static int ext4_drop_inode(struct inode *inode)
 {
 	int drop = generic_drop_inode(inode);
 
+	if (!drop)
+		drop = fscrypt_drop_inode(inode);
+
 	trace_ext4_drop_inode(inode, drop);
 	return drop;
 }