ext4: add inline encryption support
Wire up ext4 to support inline encryption via the helper functions which
fs/crypto/ now provides. This includes:
- Adding a mount option 'inlinecrypt' which enables inline encryption
on encrypted files where it can be used.
- Setting the bio_crypt_ctx on bios that will be submitted to an
inline-encrypted file.
Note: submit_bh_wbc() in fs/buffer.c also needed to be patched for
this part, since ext4 sometimes uses ll_rw_block() on file data.
- Not adding logically discontiguous data to bios that will be submitted
to an inline-encrypted file.
- Not doing filesystem-layer crypto on inline-encrypted files.
Co-developed-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20200702015607.1215430-5-satyat@google.com
Signed-off-by: Eric Biggers <ebiggers@google.com>
diff --git a/fs/buffer.c b/fs/buffer.c
index 64fe82e..dc5e05b 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -320,9 +320,8 @@ static void decrypt_bh(struct work_struct *work)
static void end_buffer_async_read_io(struct buffer_head *bh, int uptodate)
{
/* Decrypt if needed */
- if (uptodate && IS_ENABLED(CONFIG_FS_ENCRYPTION) &&
- IS_ENCRYPTED(bh->b_page->mapping->host) &&
- S_ISREG(bh->b_page->mapping->host->i_mode)) {
+ if (uptodate &&
+ fscrypt_inode_uses_fs_layer_crypto(bh->b_page->mapping->host)) {
struct decrypt_bh_ctx *ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
if (ctx) {
@@ -3046,6 +3045,8 @@ static int submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
*/
bio = bio_alloc(GFP_NOIO, 1);
+ fscrypt_set_bio_crypt_ctx_bh(bio, bh, GFP_NOIO);
+
bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
bio_set_dev(bio, bh->b_bdev);
bio->bi_write_hint = write_hint;