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btrfs-progs: Introduce function to setup temporary superblock

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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>
This commit is contained in:
Qu Wenruo 2016-01-29 13:03:15 +08:00 committed by David Sterba
parent 330ca2d6df
commit e86e5441a0
1 changed files with 116 additions and 0 deletions
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116
utils.c
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@ -215,6 +215,97 @@ static int reserve_free_space(struct cache_tree *free_tree, u64 len,
return 0;
}
static inline int write_temp_super(int fd, struct btrfs_super_block *sb,
u64 sb_bytenr)
{
u32 crc = ~(u32)0;
int ret;
crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE, crc,
BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
btrfs_csum_final(crc, (char *)&sb->csum[0]);
ret = pwrite(fd, sb, BTRFS_SUPER_INFO_SIZE, sb_bytenr);
if (ret < BTRFS_SUPER_INFO_SIZE)
ret = (ret < 0 ? -errno : -EIO);
else
ret = 0;
return ret;
}
/*
* Setup temporary superblock at cfg->super_bynter
* Needed info are extracted from cfg, and root_bytenr, chunk_bytenr
*
* For now sys chunk array will be empty and dev_item is empty too.
* They will be re-initialized at temp chunk tree setup.
*/
static int setup_temp_super(int fd, struct btrfs_mkfs_config *cfg,
u64 root_bytenr, u64 chunk_bytenr)
{
unsigned char chunk_uuid[BTRFS_UUID_SIZE];
char super_buf[BTRFS_SUPER_INFO_SIZE];
struct btrfs_super_block *super = (struct btrfs_super_block *)super_buf;
int ret;
/*
* We rely on cfg->chunk_uuid and cfg->fs_uuid to pass uuid
* for other functions.
* Caller must allocate space for them
*/
BUG_ON(!cfg->chunk_uuid || !cfg->fs_uuid);
memset(super_buf, 0, BTRFS_SUPER_INFO_SIZE);
cfg->num_bytes = round_down(cfg->num_bytes, cfg->sectorsize);
if (cfg->fs_uuid && *cfg->fs_uuid) {
if (uuid_parse(cfg->fs_uuid, super->fsid) != 0) {
error("cound not parse UUID: %s", cfg->fs_uuid);
ret = -EINVAL;
goto out;
}
if (!test_uuid_unique(cfg->fs_uuid)) {
error("non-unique UUID: %s", cfg->fs_uuid);
ret = -EINVAL;
goto out;
}
} else {
uuid_generate(super->fsid);
uuid_unparse(super->fsid, cfg->fs_uuid);
}
uuid_generate(chunk_uuid);
uuid_unparse(chunk_uuid, cfg->chunk_uuid);
btrfs_set_super_bytenr(super, cfg->super_bytenr);
btrfs_set_super_num_devices(super, 1);
btrfs_set_super_magic(super, BTRFS_MAGIC);
btrfs_set_super_generation(super, 1);
btrfs_set_super_root(super, root_bytenr);
btrfs_set_super_chunk_root(super, chunk_bytenr);
btrfs_set_super_total_bytes(super, cfg->num_bytes);
/*
* Temporary filesystem will only have 6 tree roots:
* chunk tree, root tree, extent_tree, device tree, fs tree
* and csum tree.
*/
btrfs_set_super_bytes_used(super, 6 * cfg->nodesize);
btrfs_set_super_sectorsize(super, cfg->sectorsize);
btrfs_set_super_leafsize(super, cfg->nodesize);
btrfs_set_super_nodesize(super, cfg->nodesize);
btrfs_set_super_stripesize(super, cfg->stripesize);
btrfs_set_super_csum_type(super, BTRFS_CSUM_TYPE_CRC32);
btrfs_set_super_chunk_root(super, chunk_bytenr);
btrfs_set_super_cache_generation(super, -1);
btrfs_set_super_incompat_flags(super, cfg->features);
if (cfg->label)
__strncpy_null(super->label, cfg->label, BTRFS_LABEL_SIZE - 1);
/* Sys chunk array will be re-initialized at chunk tree init time */
super->sys_chunk_array_size = 0;
ret = write_temp_super(fd, super, cfg->super_bytenr);
out:
return ret;
}
/*
* Improved version of make_btrfs().
*
@ -233,6 +324,10 @@ static int make_convert_btrfs(int fd, struct btrfs_mkfs_config *cfg,
struct cache_tree *used = &cctx->used;
u64 sys_chunk_start;
u64 meta_chunk_start;
/* chunk tree bytenr, in system chunk */
u64 chunk_bytenr;
/* metadata trees bytenr, in metadata chunk */
u64 root_bytenr;
int ret;
/* Shouldn't happen */
@ -263,6 +358,27 @@ static int make_convert_btrfs(int fd, struct btrfs_mkfs_config *cfg,
if (ret < 0)
goto out;
/*
* Inside the allocated metadata chunk, the layout will be:
* | offset | contents |
* -------------------------------------
* | +0 | tree root |
* | +nodesize | extent root |
* | +nodesize * 2 | device root |
* | +nodesize * 3 | fs tree |
* | +nodesize * 4 | csum tree |
* -------------------------------------
* Inside the allocated system chunk, the layout will be:
* | offset | contents |
* -------------------------------------
* | +0 | chunk root |
* -------------------------------------
*/
chunk_bytenr = sys_chunk_start;
root_bytenr = meta_chunk_start;
ret = setup_temp_super(fd, cfg, root_bytenr, chunk_bytenr);
if (ret < 0)
goto out;
out:
return ret;
}