Comment 1 for bug 283477

Start by retrieving the mount passphrase:
 $ ecryptfs-unwrap-passphrase ~/.ecryptfs/wrapped-passphrase LOGIN_PASSWORD

If any errors occur, you're probably not giving the correct LOGIN_PASSWORD. When you do, it will just display the MOUNT_PASSPHRASE on standard out.

To access your data, you always can manually mount as root with the MOUNT_PASSPHRASE:
 $ sudo mount -t ecryptfs ~/.Private /mnt
   (3) passphrase
   MOUNT_PASSPHRASE
   (1) aes
   (1) 16 bytes
   (n) no plaintext passthrough
   (yes) proceed with the mount as root
   (yes) add to signature cache

Or, to mount as yourself, you can manually insert the MOUNT_PASSPHRASE into your kernel keyring and then mount with:
 $ ecryptfs_insert_wrapped_passphrase_into_keyring ~/.ecryptfs/wrapped-passphrase LOGIN_PASSWORD
 $ mount.ecryptfs_private
 $ ls ~/Private

To fix this for your next boot, you may need to:
 $ ecryptfs_rewrap_passphrase ~/.ecryptfs/wrapped-passphrase PREVIOUS_LOGIN_PASSWORD NEW_LOGIN_PASSWORD

The PAM password change module has been hooked by pam_ecryptfs, so all of this should have happen automatically. Can you tell me any more about how you worked did this, in case there's an actual bug here?

:-Dustin