From: Eric Biggers <ebiggers@xxxxxxxxxx>
Add a helper function which checks if an inode is encrypted, and if so,
tries to set up its encryption key. This is a pattern which is
duplicated in multiple places in each of ext4, f2fs, and ubifs --- for
example, when a regular file is asked to be opened or truncated.
Acked-by: Dave Chinner <dchinner@xxxxxxxxxx>
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
include/linux/fscrypt.h | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index d58e6a90cfe4..b3e2a5f93415 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -151,5 +151,30 @@ static inline bool fscrypt_has_encryption_key(const struct inode *inode)
#include <linux/fscrypt_notsupp.h>
#endif /* __FS_HAS_ENCRYPTION */
+/**
+ * fscrypt_require_key - require an inode's encryption key
+ * @inode: the inode we need the key for
+ *
+ * If the inode is encrypted, set up its encryption key if not already done.
+ * Then require that the key be present and return -ENOKEY otherwise.
+ *
+ * No locks are needed, and the key will live as long as the struct inode --- so
+ * it won't go away from under you.
+ *
+ * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
+ * if a problem occurred while setting up the encryption key.
+ */
+static inline int fscrypt_require_key(struct inode *inode)
+{
+ if (IS_ENCRYPTED(inode)) {
+ int err = fscrypt_get_encryption_info(inode);
+
+ if (err)
+ return err;
+ if (!fscrypt_has_encryption_key(inode))
+ return -ENOKEY;
+ }
+ return 0;
+}
#endif /* _LINUX_FSCRYPT_H */
--
2.14.2.920.gcf0c67979c-goog
