diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c
index ee9be002c1490..08e14497c8e30 100644
--- a/fs/crypto/keyring.c
+++ b/fs/crypto/keyring.c
@@ -11,6 +11,7 @@
  *
  * - FS_IOC_ADD_ENCRYPTION_KEY: add a key
  * - FS_IOC_REMOVE_ENCRYPTION_KEY: remove a key
+ * - FS_IOC_GET_ENCRYPTION_KEY_STATUS: get key status
  */
 
 #include <linux/key-type.h>
@@ -482,6 +483,65 @@ int fscrypt_ioctl_remove_key(struct file *filp, const void __user *uarg)
 }
 EXPORT_SYMBOL_GPL(fscrypt_ioctl_remove_key);
 
+/*
+ * Retrieve the status of an fscrypt master encryption key.
+ *
+ * We set ->status to indicate whether the key is absent, present, or
+ * incompletely removed.  "Incompletely removed" means that the master key
+ * secret has been removed, but some files which had been unlocked with it are
+ * still in use.  This field allows applications to easily determine the state
+ * of an encrypted directory without using a hack such as trying to open a
+ * regular file in it (which can confuse the "incompletely removed" state with
+ * absent or present).
+ */
+int fscrypt_ioctl_get_key_status(struct file *filp, void __user *uarg)
+{
+	struct super_block *sb = file_inode(filp)->i_sb;
+	struct fscrypt_get_key_status_arg arg;
+	struct key *key;
+	struct fscrypt_master_key *mk;
+	int err;
+
+	if (copy_from_user(&arg, uarg, sizeof(arg)))
+		return -EFAULT;
+
+	if (!valid_key_spec(&arg.key_spec))
+		return -EINVAL;
+
+	if (memchr_inv(arg.__reserved, 0, sizeof(arg.__reserved)))
+		return -EINVAL;
+
+	memset(arg.__out_reserved, 0, sizeof(arg.__out_reserved));
+
+	key = fscrypt_find_master_key(sb, &arg.key_spec);
+	if (IS_ERR(key)) {
+		if (key != ERR_PTR(-ENOKEY))
+			return PTR_ERR(key);
+		arg.status = FSCRYPT_KEY_STATUS_ABSENT;
+		err = 0;
+		goto out;
+	}
+	mk = key->payload.data[0];
+	down_read(&key->sem);
+
+	if (!is_master_key_secret_present(&mk->mk_secret)) {
+		arg.status = FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED;
+		err = 0;
+		goto out_release_key;
+	}
+
+	arg.status = FSCRYPT_KEY_STATUS_PRESENT;
+	err = 0;
+out_release_key:
+	up_read(&key->sem);
+	key_put(key);
+out:
+	if (!err && copy_to_user(uarg, &arg, sizeof(arg)))
+		err = -EFAULT;
+	return err;
+}
+EXPORT_SYMBOL_GPL(fscrypt_ioctl_get_key_status);
+
 int __init fscrypt_init_keyring(void)
 {
 	return register_key_type(&key_type_fscrypt);
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index b6f8832dadba4..5f251cad255b8 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -116,6 +116,7 @@ extern int fscrypt_inherit_context(struct inode *, struct inode *,
 extern void fscrypt_sb_free(struct super_block *sb);
 extern int fscrypt_ioctl_add_key(struct file *filp, void __user *arg);
 extern int fscrypt_ioctl_remove_key(struct file *filp, const void __user *arg);
+extern int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg);
 
 /* keysetup.c */
 extern int fscrypt_get_encryption_info(struct inode *);
@@ -335,6 +336,12 @@ static inline int fscrypt_ioctl_remove_key(struct file *filp,
 	return -EOPNOTSUPP;
 }
 
+static inline int fscrypt_ioctl_get_key_status(struct file *filp,
+					       void __user *arg)
+{
+	return -EOPNOTSUPP;
+}
+
 /* keysetup.c */
 static inline int fscrypt_get_encryption_info(struct inode *inode)
 {
diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h
index 3302a407131e6..042e70a4ff7ee 100644
--- a/include/uapi/linux/fscrypt.h
+++ b/include/uapi/linux/fscrypt.h
@@ -71,11 +71,26 @@ struct fscrypt_remove_key_arg {
 	__u32 __reserved[6];
 };
 
+/* Struct passed to FS_IOC_GET_ENCRYPTION_KEY_STATUS */
+struct fscrypt_get_key_status_arg {
+	/* input */
+	struct fscrypt_key_specifier key_spec;
+	__u32 __reserved[6];
+
+	/* output */
+#define FSCRYPT_KEY_STATUS_ABSENT		1
+#define FSCRYPT_KEY_STATUS_PRESENT		2
+#define FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED	3
+	__u32 status;
+	__u32 __out_reserved[15];
+};
+
 #define FS_IOC_SET_ENCRYPTION_POLICY	  _IOR('f', 19, struct fscrypt_policy)
 #define FS_IOC_GET_ENCRYPTION_PWSALT	  _IOW('f', 20, __u8[16])
 #define FS_IOC_GET_ENCRYPTION_POLICY	  _IOW('f', 21, struct fscrypt_policy)
 #define FS_IOC_ADD_ENCRYPTION_KEY	 _IOWR('f', 23, struct fscrypt_add_key_arg)
 #define FS_IOC_REMOVE_ENCRYPTION_KEY	  _IOW('f', 24, struct fscrypt_remove_key_arg)
+#define FS_IOC_GET_ENCRYPTION_KEY_STATUS _IOWR('f', 25, struct fscrypt_get_key_status_arg)
 
 /**********************************************************************/
 
