forked from Mirrors/btrfs-progs
btrfs-progs: Introduce function to setup temporary superblock
Introduce a new function, setup_temp_super(), to setup temporary super for make_btrfs_v2(). Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> [ use __strncpy_null in setup_temp_super ] Signed-off-by: David Sterba <dsterba@suse.com>master
Qu Wenruo
David Sterba
parent
330ca2d6df
commit
e86e5441a0
116
utils.c
116
utils.c
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@ -215,6 +215,97 @@ static int reserve_free_space(struct cache_tree *free_tree, u64 len,
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return 0;
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}
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static inline int write_temp_super(int fd, struct btrfs_super_block *sb,
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u64 sb_bytenr)
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{
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u32 crc = ~(u32)0;
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int ret;
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crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE, crc,
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BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
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btrfs_csum_final(crc, (char *)&sb->csum[0]);
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ret = pwrite(fd, sb, BTRFS_SUPER_INFO_SIZE, sb_bytenr);
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if (ret < BTRFS_SUPER_INFO_SIZE)
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ret = (ret < 0 ? -errno : -EIO);
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else
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ret = 0;
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return ret;
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}
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/*
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* Setup temporary superblock at cfg->super_bynter
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* Needed info are extracted from cfg, and root_bytenr, chunk_bytenr
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*
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* For now sys chunk array will be empty and dev_item is empty too.
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* They will be re-initialized at temp chunk tree setup.
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*/
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static int setup_temp_super(int fd, struct btrfs_mkfs_config *cfg,
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u64 root_bytenr, u64 chunk_bytenr)
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{
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unsigned char chunk_uuid[BTRFS_UUID_SIZE];
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char super_buf[BTRFS_SUPER_INFO_SIZE];
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struct btrfs_super_block *super = (struct btrfs_super_block *)super_buf;
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int ret;
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/*
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* We rely on cfg->chunk_uuid and cfg->fs_uuid to pass uuid
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* for other functions.
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* Caller must allocate space for them
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*/
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BUG_ON(!cfg->chunk_uuid || !cfg->fs_uuid);
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memset(super_buf, 0, BTRFS_SUPER_INFO_SIZE);
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cfg->num_bytes = round_down(cfg->num_bytes, cfg->sectorsize);
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if (cfg->fs_uuid && *cfg->fs_uuid) {
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if (uuid_parse(cfg->fs_uuid, super->fsid) != 0) {
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error("cound not parse UUID: %s", cfg->fs_uuid);
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ret = -EINVAL;
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goto out;
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}
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if (!test_uuid_unique(cfg->fs_uuid)) {
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error("non-unique UUID: %s", cfg->fs_uuid);
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ret = -EINVAL;
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goto out;
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}
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} else {
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uuid_generate(super->fsid);
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uuid_unparse(super->fsid, cfg->fs_uuid);
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}
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uuid_generate(chunk_uuid);
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uuid_unparse(chunk_uuid, cfg->chunk_uuid);
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btrfs_set_super_bytenr(super, cfg->super_bytenr);
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btrfs_set_super_num_devices(super, 1);
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btrfs_set_super_magic(super, BTRFS_MAGIC);
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btrfs_set_super_generation(super, 1);
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btrfs_set_super_root(super, root_bytenr);
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btrfs_set_super_chunk_root(super, chunk_bytenr);
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btrfs_set_super_total_bytes(super, cfg->num_bytes);
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/*
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* Temporary filesystem will only have 6 tree roots:
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* chunk tree, root tree, extent_tree, device tree, fs tree
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* and csum tree.
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*/
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btrfs_set_super_bytes_used(super, 6 * cfg->nodesize);
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btrfs_set_super_sectorsize(super, cfg->sectorsize);
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btrfs_set_super_leafsize(super, cfg->nodesize);
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btrfs_set_super_nodesize(super, cfg->nodesize);
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btrfs_set_super_stripesize(super, cfg->stripesize);
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btrfs_set_super_csum_type(super, BTRFS_CSUM_TYPE_CRC32);
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btrfs_set_super_chunk_root(super, chunk_bytenr);
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btrfs_set_super_cache_generation(super, -1);
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btrfs_set_super_incompat_flags(super, cfg->features);
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if (cfg->label)
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__strncpy_null(super->label, cfg->label, BTRFS_LABEL_SIZE - 1);
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/* Sys chunk array will be re-initialized at chunk tree init time */
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super->sys_chunk_array_size = 0;
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ret = write_temp_super(fd, super, cfg->super_bytenr);
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out:
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return ret;
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}
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/*
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* Improved version of make_btrfs().
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*
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@ -233,6 +324,10 @@ static int make_convert_btrfs(int fd, struct btrfs_mkfs_config *cfg,
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struct cache_tree *used = &cctx->used;
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u64 sys_chunk_start;
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u64 meta_chunk_start;
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/* chunk tree bytenr, in system chunk */
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u64 chunk_bytenr;
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/* metadata trees bytenr, in metadata chunk */
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u64 root_bytenr;
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int ret;
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/* Shouldn't happen */
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@ -263,6 +358,27 @@ static int make_convert_btrfs(int fd, struct btrfs_mkfs_config *cfg,
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if (ret < 0)
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goto out;
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/*
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* Inside the allocated metadata chunk, the layout will be:
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* | offset | contents |
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* -------------------------------------
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* | +0 | tree root |
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* | +nodesize | extent root |
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* | +nodesize * 2 | device root |
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* | +nodesize * 3 | fs tree |
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* | +nodesize * 4 | csum tree |
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* -------------------------------------
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* Inside the allocated system chunk, the layout will be:
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* | offset | contents |
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* -------------------------------------
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* | +0 | chunk root |
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* -------------------------------------
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*/
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chunk_bytenr = sys_chunk_start;
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root_bytenr = meta_chunk_start;
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ret = setup_temp_super(fd, cfg, root_bytenr, chunk_bytenr);
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if (ret < 0)
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goto out;
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out:
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return ret;
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}
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