ext4 crypto: implement the ext4 decryption read path

Signed-off-by: Michael Halcrow <mhalcrow@google.com>
Signed-off-by: Ildar Muslukhov <ildarm@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 7c4527e10ae4..8b4fe626919a 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3370,6 +3370,13 @@ static int __ext4_block_zero_page_range(handle_t *handle,
                 /* Uhhuh. Read error. Complain and punt. */
                 if (!buffer_uptodate(bh))
                         goto unlock;
+                if (S_ISREG(inode->i_mode) &&
+                    ext4_encrypted_inode(inode)) {
+                        /* We expect the key to be set. */
+                        BUG_ON(!ext4_has_encryption_key(inode));
+                        BUG_ON(blocksize != PAGE_CACHE_SIZE);
+                        WARN_ON_ONCE(ext4_decrypt_one(inode, page));
+                }
         }
         if (ext4_should_journal_data(inode)) {
                 BUFFER_TRACE(bh, "get write access");