From: Josef Bacik <josef@toxicpanda.com>

This will allow file systems to set a process_bio hook for inline
encryption.  This will be utilized by btrfs in order to make sure the
checksumming work is done on the encrypted bio's.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Daniel Vacek <neelx@suse.com>
---

v5: https://lore.kernel.org/linux-btrfs/2c638e5fa1b7868dbf79d932b15364c3c30ca9de.1706116485.git.josef@toxicpanda.com/
 * No changes since.
---
 fs/crypto/inline_crypt.c |  2 +-
 include/linux/fscrypt.h  | 14 ++++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/fs/crypto/inline_crypt.c b/fs/crypto/inline_crypt.c
index d737fb6ff011..fc1aa5b00af1 100644
--- a/fs/crypto/inline_crypt.c
+++ b/fs/crypto/inline_crypt.c
@@ -179,7 +179,7 @@ int fscrypt_prepare_inline_crypt_key(struct fscrypt_prepared_key *prep_key,
 	err = blk_crypto_init_key(blk_key, key_bytes, key_size, key_type,
 				  crypto_mode, fscrypt_get_dun_bytes(ci),
 				  1U << ci->ci_data_unit_bits,
-				  NULL);
+				  sb->s_cop->process_bio);
 	if (err) {
 		fscrypt_err(inode, "error %d initializing blk-crypto key", err);
 		goto fail;
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index dba5ca122775..e3bb9e3756e1 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -16,6 +16,7 @@
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/slab.h>
+#include <linux/blk-crypto.h>
 #include <uapi/linux/fscrypt.h>
 
 /*
@@ -205,6 +206,19 @@ struct fscrypt_operations {
 	 */
 	struct block_device **(*get_devices)(struct super_block *sb,
 					     unsigned int *num_devs);
+
+	/*
+	 * A callback if the file system requires the ability to process the
+	 * encrypted bio, used only with inline encryption.
+	 *
+	 * @orig_bio: the original bio submitted.
+	 * @enc_bio: the encrypted bio.
+	 *
+	 * For writes the enc_bio will be different from the orig_bio, for reads
+	 * they will be the same.  For reads we get the bio before it is
+	 * decrypted, for writes we get the bio before it is submitted.
+	 */
+	blk_crypto_process_bio_t process_bio;
 };
 
 int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name,
-- 
2.51.0