[PATCH 2/9] btrfs-progs: use blocks_nr to determine the super used bytes

[Josef Bacik <josef@toxicpanda.com>]

We were setting the superblock's used bytes to a static number.  However
the number of blocks we have to write has the correct used size, so just
add up the total number of blocks we're allocating as we determine their
offsets.  This value will be used later which is why I'm calculating it
this way instead of doing the math to set the bytes_super specifically.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 mkfs/common.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mkfs/common.c b/mkfs/common.c
index e9ff529a..8902d39e 100644
--- a/mkfs/common.c
+++ b/mkfs/common.c
@@ -162,6 +162,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
 	u64 ref_root;
 	u32 array_size;
 	u32 item_size;
+	u64 total_used = 0;
 	int skinny_metadata = !!(cfg->features &
 				 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);
 	u64 num_bytes;
@@ -207,6 +208,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
 		if (blk == MKFS_SUPER_BLOCK)
 			continue;
 		cfg->blocks[blk] = system_group_offset + cfg->nodesize * i;
+		total_used += cfg->nodesize;
 	}
 
 	btrfs_set_super_bytenr(&super, cfg->blocks[MKFS_SUPER_BLOCK]);
@@ -216,7 +218,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
 	btrfs_set_super_root(&super, cfg->blocks[MKFS_ROOT_TREE]);
 	btrfs_set_super_chunk_root(&super, cfg->blocks[MKFS_CHUNK_TREE]);
 	btrfs_set_super_total_bytes(&super, num_bytes);
-	btrfs_set_super_bytes_used(&super, 6 * cfg->nodesize);
+	btrfs_set_super_bytes_used(&super, total_used);
 	btrfs_set_super_sectorsize(&super, cfg->sectorsize);
 	super.__unused_leafsize = cpu_to_le32(cfg->nodesize);
 	btrfs_set_super_nodesize(&super, cfg->nodesize);
-- 
2.26.3