Hi Ted, As of now root[1] can access the plain-text when the data is cached by the user-with-the-key and, root gets error no-key when data is not cached by the user-with-the-key. I think this behavior is a bug if not, wrong design, or looks like I am missing something. [1] for that matter any user who has read access to the files but does not have the keys. Repo: ----------- The user enters key of edir-user $ e4crypt add_key /ext4/edir-user/ root with no-key is not able to read file-data yet. # cat /ext4/edir-user/tf1 cat: tf1: Required key not available now the user above, reads tf1 $ cat /ext4/edir-user/tf1 this is test created by user So now root with no-key is able to read the file # cat /ext4/edir-user/tf1 this is test created by user ----------- Instead, this should either always return cipher-text (thru DIO) or always return error-no-key. So that, behavior does not depend file-data cache. Hope we agree on the common behavior, BTRFS as of now returns error-no-key for all users without-the-key, however in the long term when relevant code is ready, it would be beneficial to provide the cipher-text in this context and the encryption metadata through the xattr. So that, we could use rsync -X without-key, to back up the encrypted files which will also copy the required encryption metadata through the extended attributes. Next, when rsync -X is run when key-is-in, it would read plain-text but no encryption metadata should be read at this time, as it has already reading the plain-text anyway. In this way we control the backup and restore. This may be controversial but just the idea floating so that we have better compatibility and, as probably extended attribute is more common across other OSs including NTFS, hopefully one day we could backup encrypted-file across FSs without having to decrypt, and decrypt at the destination only when required. This also means we need page->index to be common or we can provide such info through the extended attributes again or fs/crypto v2 could add a feature to drop encryption metadata dependency on the page->index. Thanks, Anand
