[PATCH 3/9] btrfs-progs: allocate blocks from the start of the temp system chunk

[Josef Bacik <josef@toxicpanda.com>]

During mkfs we skip allocating a block for the super block, however
because we're using the blocks array iterator to determine the offset of
our block we're leaving a hole at the beginning of the temporary chunk.
This isn't a problem per-se, but I'm going to start generating the free
space tree at make_btrfs() time and having this hole makes the free
space tree creation slightly more complicated.

Instead keep track of which block we're on so that we start from the
actual offset of the system chunk.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 mkfs/common.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mkfs/common.c b/mkfs/common.c
index 8902d39e..0e747301 100644
--- a/mkfs/common.c
+++ b/mkfs/common.c
@@ -153,6 +153,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
 	u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
 	u8 *ptr;
 	int i;
+	int cnt;
 	int ret;
 	int blocks_nr = ARRAY_SIZE(extent_tree_v1_blocks);
 	int blk;
@@ -203,11 +204,11 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
 	uuid_generate(chunk_tree_uuid);
 
 	cfg->blocks[MKFS_SUPER_BLOCK] = BTRFS_SUPER_INFO_OFFSET;
-	for (i = 0; i < blocks_nr; i++) {
+	for (cnt = 0, i = 0; i < blocks_nr; i++) {
 		blk = blocks[i];
 		if (blk == MKFS_SUPER_BLOCK)
 			continue;
-		cfg->blocks[blk] = system_group_offset + cfg->nodesize * i;
+		cfg->blocks[blk] = system_group_offset + cfg->nodesize * cnt++;
 		total_used += cfg->nodesize;
 	}
 
-- 
2.26.3