From df20ed3e5eafa61fe2ef8dcdb92af06691ba8eec Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Fri, 29 Jan 2016 13:03:16 +0800 Subject: btrfs-progs: Introduce function to setup temporary tree root Introduce new function, setup_temp_tree_root(), to initialize temporary tree root for make_btrfs_v2(). The new function will setup tree root at metadata chunk and ensure data won't be written into metadata chunk. Also, new make_btrfs_v2() will have a much better code structure than old make_btrfs(). Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- utils.c | 147 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 147 insertions(+) diff --git a/utils.c b/utils.c index 368c32a2..ea1d5ce6 100644 --- a/utils.c +++ b/utils.c @@ -306,6 +306,136 @@ out: return ret; } +/* + * Setup an extent buffer for tree block. + */ +static int setup_temp_extent_buffer(struct extent_buffer *buf, + struct btrfs_mkfs_config *cfg, + u64 bytenr, u64 owner) +{ + unsigned char fsid[BTRFS_FSID_SIZE]; + unsigned char chunk_uuid[BTRFS_UUID_SIZE]; + int ret; + + /* We rely on cfg->fs_uuid and chunk_uuid to fsid and chunk uuid */ + BUG_ON(!cfg->fs_uuid || !cfg->chunk_uuid); + ret = uuid_parse(cfg->fs_uuid, fsid); + if (ret) + return -EINVAL; + ret = uuid_parse(cfg->chunk_uuid, chunk_uuid); + if (ret) + return -EINVAL; + + memset(buf->data, 0, cfg->nodesize); + buf->len = cfg->nodesize; + btrfs_set_header_bytenr(buf, bytenr); + btrfs_set_header_generation(buf, 1); + btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV); + btrfs_set_header_owner(buf, owner); + btrfs_set_header_flags(buf, BTRFS_HEADER_FLAG_WRITTEN); + write_extent_buffer(buf, chunk_uuid, btrfs_header_chunk_tree_uuid(buf), + BTRFS_UUID_SIZE); + write_extent_buffer(buf, fsid, btrfs_header_fsid(), BTRFS_FSID_SIZE); + return 0; +} + +static inline int write_temp_extent_buffer(int fd, struct extent_buffer *buf, + u64 bytenr) +{ + int ret; + + csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0); + + /* Temporary extent buffer is always mapped 1:1 on disk */ + ret = pwrite(fd, buf->data, buf->len, bytenr); + if (ret < buf->len) + ret = (ret < 0 ? ret : -EIO); + else + ret = 0; + return ret; +} + +/* + * Insert a root item for temporary tree root + * + * Only used in make_btrfs_v2(). + */ +static void insert_temp_root_item(struct extent_buffer *buf, + struct btrfs_mkfs_config *cfg, + int *slot, u32 *itemoff, u64 objectid, + u64 bytenr) +{ + struct btrfs_root_item root_item; + struct btrfs_inode_item *inode_item; + struct btrfs_disk_key disk_key; + + btrfs_set_header_nritems(buf, *slot + 1); + (*itemoff) -= sizeof(root_item); + memset(&root_item, 0, sizeof(root_item)); + inode_item = &root_item.inode; + btrfs_set_stack_inode_generation(inode_item, 1); + btrfs_set_stack_inode_size(inode_item, 3); + btrfs_set_stack_inode_nlink(inode_item, 1); + btrfs_set_stack_inode_nbytes(inode_item, cfg->nodesize); + btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755); + btrfs_set_root_refs(&root_item, 1); + btrfs_set_root_used(&root_item, cfg->nodesize); + btrfs_set_root_generation(&root_item, 1); + btrfs_set_root_bytenr(&root_item, bytenr); + + memset(&disk_key, 0, sizeof(disk_key)); + btrfs_set_disk_key_type(&disk_key, BTRFS_ROOT_ITEM_KEY); + btrfs_set_disk_key_objectid(&disk_key, objectid); + btrfs_set_disk_key_offset(&disk_key, 0); + + btrfs_set_item_key(buf, &disk_key, *slot); + btrfs_set_item_offset(buf, btrfs_item_nr(*slot), *itemoff); + btrfs_set_item_size(buf, btrfs_item_nr(*slot), sizeof(root_item)); + write_extent_buffer(buf, &root_item, + btrfs_item_ptr_offset(buf, *slot), + sizeof(root_item)); + (*slot)++; +} + +static int setup_temp_root_tree(int fd, struct btrfs_mkfs_config *cfg, + u64 root_bytenr, u64 extent_bytenr, + u64 dev_bytenr, u64 fs_bytenr, u64 csum_bytenr) +{ + struct extent_buffer *buf = NULL; + u32 itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize); + int slot = 0; + int ret; + + /* + * Provided bytenr must in ascending order, or tree root will have a + * bad key order. + */ + BUG_ON(!(root_bytenr < extent_bytenr && extent_bytenr < dev_bytenr && + dev_bytenr < fs_bytenr && fs_bytenr < csum_bytenr)); + buf = malloc(sizeof(*buf) + cfg->nodesize); + if (!buf) + return -ENOMEM; + + ret = setup_temp_extent_buffer(buf, cfg, root_bytenr, + BTRFS_ROOT_TREE_OBJECTID); + if (ret < 0) + goto out; + + insert_temp_root_item(buf, cfg, &slot, &itemoff, + BTRFS_EXTENT_TREE_OBJECTID, extent_bytenr); + insert_temp_root_item(buf, cfg, &slot, &itemoff, + BTRFS_DEV_TREE_OBJECTID, dev_bytenr); + insert_temp_root_item(buf, cfg, &slot, &itemoff, + BTRFS_FS_TREE_OBJECTID, fs_bytenr); + insert_temp_root_item(buf, cfg, &slot, &itemoff, + BTRFS_CSUM_TREE_OBJECTID, csum_bytenr); + + ret = write_temp_extent_buffer(fd, buf, root_bytenr); +out: + free(buf); + return ret; +} + /* * Improved version of make_btrfs(). * @@ -328,6 +458,10 @@ static int make_convert_btrfs(int fd, struct btrfs_mkfs_config *cfg, u64 chunk_bytenr; /* metadata trees bytenr, in metadata chunk */ u64 root_bytenr; + u64 extent_bytenr; + u64 dev_bytenr; + u64 fs_bytenr; + u64 csum_bytenr; int ret; /* Shouldn't happen */ @@ -359,6 +493,8 @@ static int make_convert_btrfs(int fd, struct btrfs_mkfs_config *cfg, goto out; /* + * Allocated meta/sys chunks will be mapped 1:1 with device offset. + * * Inside the allocated metadata chunk, the layout will be: * | offset | contents | * ------------------------------------- @@ -376,9 +512,20 @@ static int make_convert_btrfs(int fd, struct btrfs_mkfs_config *cfg, */ chunk_bytenr = sys_chunk_start; root_bytenr = meta_chunk_start; + extent_bytenr = meta_chunk_start + cfg->nodesize; + dev_bytenr = meta_chunk_start + cfg->nodesize * 2; + fs_bytenr = meta_chunk_start + cfg->nodesize * 3; + csum_bytenr = meta_chunk_start + cfg->nodesize * 4; + ret = setup_temp_super(fd, cfg, root_bytenr, chunk_bytenr); if (ret < 0) goto out; + + ret = setup_temp_root_tree(fd, cfg, root_bytenr, extent_bytenr, + dev_bytenr, fs_bytenr, csum_bytenr); + if (ret < 0) + goto out; + out: return ret; } -- cgit v1.2.3