From d13a6f7487eb7519bc1e4302085b21ca98afabc0 Mon Sep 17 00:00:00 2001
From: Ondrej Kozina <okozina@redhat.com>
Date: Thu, 22 Aug 2019 17:05:43 +0200
Subject: [PATCH 1/5] Take optimal io size in account with LUKS2 reencryption.

If device properly exposes optimal io size, let's align
reencryption hotzone to it. Otherwise device-mapper driver
complaints about misaligned tables and reencryption performance
is not optimal.
---
 lib/luks2/luks2_reencrypt.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/lib/luks2/luks2_reencrypt.c b/lib/luks2/luks2_reencrypt.c
index 1d70aaf..1f5eb5f 100644
--- a/lib/luks2/luks2_reencrypt.c
+++ b/lib/luks2/luks2_reencrypt.c
@@ -817,8 +817,13 @@ static int reencrypt_offset(struct luks2_hdr *hdr,
 	return -EINVAL;
 }
 
-static uint64_t reencrypt_length(struct luks2_hdr *hdr, struct luks2_reenc_context *rh, uint64_t keyslot_area_length, uint64_t length_max)
+static uint64_t reencrypt_length(struct crypt_device *cd,
+		struct luks2_hdr *hdr,
+		struct luks2_reenc_context *rh,
+		uint64_t keyslot_area_length,
+		uint64_t length_max)
 {
+	unsigned long dummy, optimal_alignment;
 	uint64_t length;
 
 	if (rh->rp.type == REENC_PROTECTION_NONE)
@@ -835,6 +840,20 @@ static uint64_t reencrypt_length(struct luks2_hdr *hdr, struct luks2_reenc_conte
 
 	length -= (length % rh->alignment);
 
+	/* Emits error later */
+	if (!length)
+		return length;
+
+	device_topology_alignment(cd, crypt_data_device(cd), &optimal_alignment, &dummy, length);
+
+	/* we have to stick with encryption sector size alignment */
+	if (optimal_alignment % rh->alignment)
+		return length;
+
+	/* align to opt-io size only if remaining size allows it */
+	if (length > optimal_alignment)
+		length -= (length % optimal_alignment);
+
 	return length;
 }
 
@@ -920,7 +939,7 @@ static int reencrypt_context_init(struct crypt_device *cd, struct luks2_hdr *hdr
 	} else
 		rh->fixed_length = false;
 
-	rh->length = reencrypt_length(hdr, rh, area_length, params->max_hotzone_size << SECTOR_SHIFT);
+	rh->length = reencrypt_length(cd, hdr, rh, area_length, params->max_hotzone_size << SECTOR_SHIFT);
 	if (reencrypt_offset(hdr, rh->direction, device_size, &rh->length, &rh->offset)) {
 		log_dbg(cd, "Failed to get reencryption offset.");
 		return -EINVAL;
-- 
1.8.3.1