[PATCH v2 01/10] btrfs-progs: mkfs: use an associative array for init blocks

[Josef Bacik <josef@toxicpanda.com>]

Extent tree v2 will not create an extent tree or csum tree initially,
and it will create a block group tree.  To handle this we want to rework
the initial mkfs step to take an array of the blocks we want to create
and use the array to keep track of which blocks we need to create.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
 mkfs/common.c | 53 ++++++++++++++++++++++++++++++++-------------------
 mkfs/common.h | 10 ++++++++++
 2 files changed, 43 insertions(+), 20 deletions(-)

diff --git a/mkfs/common.c b/mkfs/common.c
index 2c041224..35ee4bff 100644
--- a/mkfs/common.c
+++ b/mkfs/common.c
@@ -31,16 +31,18 @@
 #include "mkfs/common.h"
 
 static u64 reference_root_table[] = {
-	[1] =	BTRFS_ROOT_TREE_OBJECTID,
-	[2] =	BTRFS_EXTENT_TREE_OBJECTID,
-	[3] =	BTRFS_CHUNK_TREE_OBJECTID,
-	[4] =	BTRFS_DEV_TREE_OBJECTID,
-	[5] =	BTRFS_FS_TREE_OBJECTID,
-	[6] =	BTRFS_CSUM_TREE_OBJECTID,
+	[MKFS_ROOT_TREE]	=	BTRFS_ROOT_TREE_OBJECTID,
+	[MKFS_EXTENT_TREE]	=	BTRFS_EXTENT_TREE_OBJECTID,
+	[MKFS_CHUNK_TREE]	=	BTRFS_CHUNK_TREE_OBJECTID,
+	[MKFS_DEV_TREE]		=	BTRFS_DEV_TREE_OBJECTID,
+	[MKFS_FS_TREE]		=	BTRFS_FS_TREE_OBJECTID,
+	[MKFS_CSUM_TREE]	=	BTRFS_CSUM_TREE_OBJECTID,
 };
 
 static int btrfs_create_tree_root(int fd, struct btrfs_mkfs_config *cfg,
-			struct extent_buffer *buf)
+				  struct extent_buffer *buf,
+				  const enum btrfs_mkfs_block *blocks,
+				  int blocks_nr)
 {
 	struct btrfs_root_item root_item;
 	struct btrfs_inode_item *inode_item;
@@ -49,6 +51,7 @@ static int btrfs_create_tree_root(int fd, struct btrfs_mkfs_config *cfg,
 	u32 itemoff;
 	int ret = 0;
 	int blk;
+	int i;
 	u8 uuid[BTRFS_UUID_SIZE];
 
 	memset(buf->data + sizeof(struct btrfs_header), 0,
@@ -71,7 +74,8 @@ static int btrfs_create_tree_root(int fd, struct btrfs_mkfs_config *cfg,
 	btrfs_set_disk_key_offset(&disk_key, 0);
 	itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize) - sizeof(root_item);
 
-	for (blk = 0; blk < MKFS_BLOCK_COUNT; blk++) {
+	for (i = 0; i < blocks_nr; i++) {
+		blk = blocks[i];
 		if (blk == MKFS_SUPER_BLOCK || blk == MKFS_ROOT_TREE
 		    || blk == MKFS_CHUNK_TREE)
 			continue;
@@ -145,10 +149,13 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
 	struct btrfs_chunk *chunk;
 	struct btrfs_dev_item *dev_item;
 	struct btrfs_dev_extent *dev_extent;
+	const enum btrfs_mkfs_block *blocks = extent_tree_v1_blocks;
 	u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
 	u8 *ptr;
 	int i;
 	int ret;
+	int blocks_nr = ARRAY_SIZE(extent_tree_v1_blocks);
+	int blk;
 	u32 itemoff;
 	u32 nritems = 0;
 	u64 first_free;
@@ -195,7 +202,10 @@ 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 = 1; i < MKFS_BLOCK_COUNT; i++) {
+	for (i = 0; i < blocks_nr; i++) {
+		blk = blocks[i];
+		if (blk == MKFS_SUPER_BLOCK)
+			continue;
 		cfg->blocks[i] = system_group_offset + cfg->nodesize * (i - 1);
 	}
 
@@ -236,7 +246,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
 			    btrfs_header_chunk_tree_uuid(buf),
 			    BTRFS_UUID_SIZE);
 
-	ret = btrfs_create_tree_root(fd, cfg, buf);
+	ret = btrfs_create_tree_root(fd, cfg, buf, blocks, blocks_nr);
 	if (ret < 0)
 		goto out;
 
@@ -245,30 +255,33 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
 		cfg->nodesize - sizeof(struct btrfs_header));
 	nritems = 0;
 	itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize);
-	for (i = 1; i < MKFS_BLOCK_COUNT; i++) {
+	for (i = 0; i < blocks_nr; i++) {
+		blk = blocks[i];
+		if (blk == MKFS_SUPER_BLOCK)
+			continue;
 		item_size = sizeof(struct btrfs_extent_item);
 		if (!skinny_metadata)
 			item_size += sizeof(struct btrfs_tree_block_info);
 
-		if (cfg->blocks[i] < first_free) {
+		if (cfg->blocks[blk] < first_free) {
 			error("block[%d] below first free: %llu < %llu",
-					i, (unsigned long long)cfg->blocks[i],
+					i, (unsigned long long)cfg->blocks[blk],
 					(unsigned long long)first_free);
 			ret = -EINVAL;
 			goto out;
 		}
-		if (cfg->blocks[i] < cfg->blocks[i - 1]) {
+		if (cfg->blocks[blk] < cfg->blocks[blocks[i - 1]]) {
 			error("blocks %d and %d in reverse order: %llu < %llu",
-				i, i - 1,
-				(unsigned long long)cfg->blocks[i],
-				(unsigned long long)cfg->blocks[i - 1]);
+				blk, blocks[i - 1],
+				(unsigned long long)cfg->blocks[blk],
+				(unsigned long long)cfg->blocks[blocks[i - 1]]);
 			ret = -EINVAL;
 			goto out;
 		}
 
 		/* create extent item */
 		itemoff -= item_size;
-		btrfs_set_disk_key_objectid(&disk_key, cfg->blocks[i]);
+		btrfs_set_disk_key_objectid(&disk_key, cfg->blocks[blk]);
 		if (skinny_metadata) {
 			btrfs_set_disk_key_type(&disk_key,
 						BTRFS_METADATA_ITEM_KEY);
@@ -292,8 +305,8 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
 		nritems++;
 
 		/* create extent ref */
-		ref_root = reference_root_table[i];
-		btrfs_set_disk_key_objectid(&disk_key, cfg->blocks[i]);
+		ref_root = reference_root_table[blk];
+		btrfs_set_disk_key_objectid(&disk_key, cfg->blocks[blk]);
 		btrfs_set_disk_key_offset(&disk_key, ref_root);
 		btrfs_set_disk_key_type(&disk_key, BTRFS_TREE_BLOCK_REF_KEY);
 		btrfs_set_item_key(buf, &disk_key, nritems);
diff --git a/mkfs/common.h b/mkfs/common.h
index ea87c3ca..378da6bd 100644
--- a/mkfs/common.h
+++ b/mkfs/common.h
@@ -55,6 +55,16 @@ enum btrfs_mkfs_block {
 	MKFS_BLOCK_COUNT
 };
 
+static const enum btrfs_mkfs_block extent_tree_v1_blocks[] = {
+	MKFS_SUPER_BLOCK,
+	MKFS_ROOT_TREE,
+	MKFS_EXTENT_TREE,
+	MKFS_CHUNK_TREE,
+	MKFS_DEV_TREE,
+	MKFS_FS_TREE,
+	MKFS_CSUM_TREE,
+};
+
 struct btrfs_mkfs_config {
 	/* Label of the new filesystem */
 	const char *label;
-- 
2.26.3