[PATCH 01/29] fscrypt: Add in-place encryption mode

[Eric Biggers]

Hi,

On Sun, Nov 13, 2016 at 10:20:44PM +0100, Richard Weinberger wrote:
> From: David Gstir <david at sigma-star.at>
> 
> ext4 and f2fs require a bounce page when encrypting pages. However, not
> all filesystems will need that (eg. UBIFS). This is handled via a
> flag on fscrypt_operations where a fs implementation can select in-place
> encryption over using a bounce page (which is the default).
> 
> Signed-off-by: David Gstir <david at sigma-star.at>
> Signed-off-by: Richard Weinberger <richard at nod.at>

The comment for fscrypt_encrypt_page() still says the following:

 * Called on the page write path.  The caller must call
 * fscrypt_restore_control_page() on the returned ciphertext page to
 * release the bounce buffer and the encryption context.

It seems this isn't correct anymore.  It also looks like the fscrypt_context
never gets released in the case where the page is encrypted in-place.

Additionally, after this change the name of the flag FS_WRITE_PATH_FL is
misleading, since it now really indicates the presence of a bounce buffer rather
than the "write path".

Eric