From 3b6ae63e496d5e7c1ebbbf570ce26379ca55499d Mon Sep 17 00:00:00 2001
From: Gabriel <g2p.code@gmail.com>
Date: Sat, 9 Mar 2013 15:51:17 +0100
Subject: [PATCH] Fix offsets, cache and backing are two different cases.

---
 bcache-super-show.c | 26 +++++++++++++++++---------
 bcache.h            |  2 ++
 make-bcache.c       |  8 ++++----
 3 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/bcache-super-show.c b/bcache-super-show.c
index 6f9f6a75..97154cd9 100644
--- a/bcache-super-show.c
+++ b/bcache-super-show.c
@@ -97,12 +97,12 @@ int main(int argc, char **argv)
 
 	printf("sb.version\t\t%" PRIu64, sb.version);
 	switch (sb.version) {
-		case 1:
-			printf(" [backing device]\n");
+		case 0:
+			printf(" [cache device]\n");
 			break;
 
-		case 2:
-			printf(" [cache device]\n");
+		case CACHE_BACKING_DEV: // 1
+			printf(" [backing device]\n");
 			break;
 
 		case 3:
@@ -125,15 +125,23 @@ int main(int argc, char **argv)
 			"dev.sectors_per_block\t%u\n"
 			"dev.sectors_per_bucket\t%u\n"
 			"dev.bucket_count\t%ju\n"
-			"dev.cache_count\t\t%u\n" // expect version == 2 ? 1 : 0
-			"dev.data.first_bucket\t%u\n",
+			"dev.cache_count\t\t%u\n", // expect version == 0 ? 1 : 0
 			sb.block_size,
 			sb.bucket_size,
 			sb.nbuckets,
-			sb.nr_this_dev,
-			sb.first_bucket);
+			sb.nr_this_dev);
 
-	printf("dev.data.first_sector\t%u\n", sb.bucket_size * sb.first_bucket);
+	if (sb.version == 0) {
+		printf(
+				"dev.cache.first_bucket\t%u\n"
+				"dev.cache.first_sector\t%u\n",
+				sb.first_bucket,
+				sb.bucket_size * sb.first_bucket);
+	} else if (sb.version == CACHE_BACKING_DEV) {
+		printf(
+				"dev.data.first_sector\t%u\n",
+				BDEV_DATA_START);
+	}
 	putchar('\n');
 
 	uuid_unparse(sb.set_uuid, uuid);
diff --git a/bcache.h b/bcache.h
index 8087092f..2e015499 100644
--- a/bcache.h
+++ b/bcache.h
@@ -25,6 +25,8 @@ static const char bcache_magic[] = {
 
 #define SB_SECTOR		8
 #define SB_LABEL_SIZE		32
+#define BDEV_DATA_START		16	/* sectors */
+
 
 struct cache_sb {
 	uint64_t		csum;
diff --git a/make-bcache.c b/make-bcache.c
index e20a7cf6..5f4ebcca 100644
--- a/make-bcache.c
+++ b/make-bcache.c
@@ -154,7 +154,7 @@ const char * const cache_replacement_policies[] = {
 int writeback;
 int discard;
 unsigned cache_replacement_policy;
-uint64_t data_offset = 16;
+uint64_t data_offset = BDEV_DATA_START;
 
 struct option opts[] = {
 	{ "cache",		0, NULL,	'C' },
@@ -194,7 +194,7 @@ void write_sb(char *dev, struct cache_sb *sb)
 	if (SB_BDEV(sb)) {
 		SET_BDEV_WRITEBACK(sb, writeback);
 
-		if (data_offset != 16) {
+		if (data_offset != BDEV_DATA_START) {
 			sb->version = BCACHE_SB_BDEV_VERSION;
 			sb->keys = 1;
 			sb->d[0] = data_offset;
@@ -288,8 +288,8 @@ int main(int argc, char **argv)
 			break;
 		case 'o':
 			data_offset = atoll(optarg);
-			if (sb.d[0] < 16) {
-				printf("Bad data offset; minimum 16 sectors\n");
+			if (sb.d[0] < BDEV_DATA_START) {
+				printf("Bad data offset; minimum %d sectors\n", BDEV_DATA_START);
 				exit(EXIT_FAILURE);
 			}
 			break;