On Wed, Jun 28, 2017 at 05:59:24PM +0800, Gu Jinxiang wrote:
> For code maintainability and scalability,
> replace hardcoded constant with a meaningful enum.
>
> Signed-off-by: Gu Jinxiang <gujx@xxxxxxxxxxxxxx>
Sorry for late reply. Patch applied with some tweaks, the added enum
names are too generic, so I've added some prefix.
> ---
> mkfs/common.c | 47 ++++++++++++++++++++++++-----------------------
> mkfs/common.h | 14 +++++++++++++-
> 2 files changed, 37 insertions(+), 24 deletions(-)
>
> diff --git a/mkfs/common.c b/mkfs/common.c
> index e4785c5..f34c4eb 100644
> --- a/mkfs/common.c
> +++ b/mkfs/common.c
> @@ -93,18 +93,18 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
> uuid_generate(super.dev_item.uuid);
> uuid_generate(chunk_tree_uuid);
>
> - cfg->blocks[0] = BTRFS_SUPER_INFO_OFFSET;
> - for (i = 1; i < 7; i++) {
> + cfg->blocks[SUPER_BLOCK] = BTRFS_SUPER_INFO_OFFSET;
> + for (i = 1; i < BLOCK_COUNT; i++) {
> cfg->blocks[i] = BTRFS_SUPER_INFO_OFFSET + 1024 * 1024 +
> cfg->nodesize * i;
> }
>
> - btrfs_set_super_bytenr(&super, cfg->blocks[0]);
> + btrfs_set_super_bytenr(&super, cfg->blocks[SUPER_BLOCK]);
> btrfs_set_super_num_devices(&super, 1);
> btrfs_set_super_magic(&super, BTRFS_MAGIC_PARTIAL);
> btrfs_set_super_generation(&super, 1);
> - btrfs_set_super_root(&super, cfg->blocks[1]);
> - btrfs_set_super_chunk_root(&super, cfg->blocks[3]);
> + btrfs_set_super_root(&super, cfg->blocks[ROOT_TREE]);
> + btrfs_set_super_chunk_root(&super, cfg->blocks[CHUNK_TREE]);
> btrfs_set_super_total_bytes(&super, num_bytes);
> btrfs_set_super_bytes_used(&super, 6 * cfg->nodesize);
> btrfs_set_super_sectorsize(&super, cfg->sectorsize);
> @@ -121,7 +121,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
> /* create the tree of root objects */
> memset(buf->data, 0, cfg->nodesize);
> buf->len = cfg->nodesize;
> - btrfs_set_header_bytenr(buf, cfg->blocks[1]);
> + btrfs_set_header_bytenr(buf, cfg->blocks[ROOT_TREE]);
> btrfs_set_header_nritems(buf, 4);
> btrfs_set_header_generation(buf, 1);
> btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
> @@ -151,7 +151,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
> nritems = 0;
>
> itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize) - sizeof(root_item);
> - btrfs_set_root_bytenr(&root_item, cfg->blocks[2]);
> + btrfs_set_root_bytenr(&root_item, cfg->blocks[EXTENT_TREE]);
> btrfs_set_disk_key_objectid(&disk_key, BTRFS_EXTENT_TREE_OBJECTID);
> btrfs_set_item_key(buf, &disk_key, nritems);
> btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
> @@ -162,7 +162,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
> nritems++;
>
> itemoff = itemoff - sizeof(root_item);
> - btrfs_set_root_bytenr(&root_item, cfg->blocks[4]);
> + btrfs_set_root_bytenr(&root_item, cfg->blocks[DEV_TREE]);
> btrfs_set_disk_key_objectid(&disk_key, BTRFS_DEV_TREE_OBJECTID);
> btrfs_set_item_key(buf, &disk_key, nritems);
> btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
> @@ -174,7 +174,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
> nritems++;
>
> itemoff = itemoff - sizeof(root_item);
> - btrfs_set_root_bytenr(&root_item, cfg->blocks[5]);
> + btrfs_set_root_bytenr(&root_item, cfg->blocks[FS_TREE]);
> btrfs_set_disk_key_objectid(&disk_key, BTRFS_FS_TREE_OBJECTID);
> btrfs_set_item_key(buf, &disk_key, nritems);
> btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
> @@ -186,7 +186,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
> nritems++;
>
> itemoff = itemoff - sizeof(root_item);
> - btrfs_set_root_bytenr(&root_item, cfg->blocks[6]);
> + btrfs_set_root_bytenr(&root_item, cfg->blocks[CSUM_TREE]);
> btrfs_set_disk_key_objectid(&disk_key, BTRFS_CSUM_TREE_OBJECTID);
> btrfs_set_item_key(buf, &disk_key, nritems);
> btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
> @@ -199,7 +199,7 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
>
>
> csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
> - ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[1]);
> + ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[ROOT_TREE]);
> if (ret != cfg->nodesize) {
> ret = (ret < 0 ? -errno : -EIO);
> goto out;
> @@ -210,7 +210,7 @@ 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 < 7; i++) {
> + for (i = 1; i < BLOCK_COUNT; i++) {
> item_size = sizeof(struct btrfs_extent_item);
> if (!skinny_metadata)
> item_size += sizeof(struct btrfs_tree_block_info);
> @@ -267,11 +267,11 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
> btrfs_set_item_size(buf, btrfs_item_nr(nritems), 0);
> nritems++;
> }
> - btrfs_set_header_bytenr(buf, cfg->blocks[2]);
> + btrfs_set_header_bytenr(buf, cfg->blocks[EXTENT_TREE]);
> btrfs_set_header_owner(buf, BTRFS_EXTENT_TREE_OBJECTID);
> btrfs_set_header_nritems(buf, nritems);
> csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
> - ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[2]);
> + ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[EXTENT_TREE]);
> if (ret != cfg->nodesize) {
> ret = (ret < 0 ? -errno : -EIO);
> goto out;
> @@ -354,11 +354,11 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
> ptr += item_size;
> btrfs_set_super_sys_array_size(&super, array_size);
>
> - btrfs_set_header_bytenr(buf, cfg->blocks[3]);
> + btrfs_set_header_bytenr(buf, cfg->blocks[CHUNK_TREE]);
> btrfs_set_header_owner(buf, BTRFS_CHUNK_TREE_OBJECTID);
> btrfs_set_header_nritems(buf, nritems);
> csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
> - ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[3]);
> + ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[CHUNK_TREE]);
> if (ret != cfg->nodesize) {
> ret = (ret < 0 ? -errno : -EIO);
> goto out;
> @@ -393,11 +393,11 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
> BTRFS_MKFS_SYSTEM_GROUP_SIZE);
> nritems++;
>
> - btrfs_set_header_bytenr(buf, cfg->blocks[4]);
> + btrfs_set_header_bytenr(buf, cfg->blocks[DEV_TREE]);
> btrfs_set_header_owner(buf, BTRFS_DEV_TREE_OBJECTID);
> btrfs_set_header_nritems(buf, nritems);
> csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
> - ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[4]);
> + ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[DEV_TREE]);
> if (ret != cfg->nodesize) {
> ret = (ret < 0 ? -errno : -EIO);
> goto out;
> @@ -406,11 +406,11 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
> /* create the FS root */
> memset(buf->data + sizeof(struct btrfs_header), 0,
> cfg->nodesize - sizeof(struct btrfs_header));
> - btrfs_set_header_bytenr(buf, cfg->blocks[5]);
> + btrfs_set_header_bytenr(buf, cfg->blocks[FS_TREE]);
> btrfs_set_header_owner(buf, BTRFS_FS_TREE_OBJECTID);
> btrfs_set_header_nritems(buf, 0);
> csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
> - ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[5]);
> + ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[FS_TREE]);
> if (ret != cfg->nodesize) {
> ret = (ret < 0 ? -errno : -EIO);
> goto out;
> @@ -418,11 +418,11 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
> /* finally create the csum root */
> memset(buf->data + sizeof(struct btrfs_header), 0,
> cfg->nodesize - sizeof(struct btrfs_header));
> - btrfs_set_header_bytenr(buf, cfg->blocks[6]);
> + btrfs_set_header_bytenr(buf, cfg->blocks[CSUM_TREE]);
> btrfs_set_header_owner(buf, BTRFS_CSUM_TREE_OBJECTID);
> btrfs_set_header_nritems(buf, 0);
> csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
> - ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[6]);
> + ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[CSUM_TREE]);
> if (ret != cfg->nodesize) {
> ret = (ret < 0 ? -errno : -EIO);
> goto out;
> @@ -433,7 +433,8 @@ int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
> memcpy(buf->data, &super, sizeof(super));
> buf->len = BTRFS_SUPER_INFO_SIZE;
> csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
> - ret = pwrite(fd, buf->data, BTRFS_SUPER_INFO_SIZE, cfg->blocks[0]);
> + ret = pwrite(fd, buf->data, BTRFS_SUPER_INFO_SIZE,
> + cfg->blocks[SUPER_BLOCK]);
> if (ret != BTRFS_SUPER_INFO_SIZE) {
> ret = (ret < 0 ? -errno : -EIO);
> goto out;
> diff --git a/mkfs/common.h b/mkfs/common.h
> index 666a75b..4d8a314 100644
> --- a/mkfs/common.h
> +++ b/mkfs/common.h
> @@ -28,6 +28,18 @@
> #define BTRFS_MKFS_SYSTEM_GROUP_SIZE SZ_4M
> #define BTRFS_MKFS_SMALL_VOLUME_SIZE SZ_1G
>
> +/* roots: root tree, extent tree, chunk tree, dev tree, fs tree, csum tree */
> +enum btrfs_mkfs_block {
> + SUPER_BLOCK = 0,
> + ROOT_TREE,
> + EXTENT_TREE,
> + CHUNK_TREE,
> + DEV_TREE,
> + FS_TREE,
> + CSUM_TREE,
> + BLOCK_COUNT
> +};
> +
> struct btrfs_mkfs_config {
> /* Label of the new filesystem */
> const char *label;
> @@ -43,7 +55,7 @@ struct btrfs_mkfs_config {
> /* Output fields, set during creation */
>
> /* Logical addresses of superblock [0] and other tree roots */
> - u64 blocks[8];
> + u64 blocks[BLOCK_COUNT];
> char fs_uuid[BTRFS_UUID_UNPARSED_SIZE];
> char chunk_uuid[BTRFS_UUID_UNPARSED_SIZE];
>
> --
> 2.9.4
>
>
>
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