1. A method comprising: determining, by a computer, that plaintext data stored in a plaintext buffer is to be written out to an encrypted storage resource; in response to the determination, allocating an encryption buffer; copying the plaintext data from the plaintext buffer to the encryption buffer; encrypting the plaintext data of the encryption buffer to generate encrypted data; writing the encrypted data from the encryption buffer to the encrypted storage resource; de-allocating the encryption buffer; and simultaneously satisfying read and write requests from a client by retrieving the plaintext data from the plaintext buffer while the encryption is proceeding.