On Fri, Jan 29, 2016 at 01:03:15PM +0800, Qu Wenruo wrote:
> Introduce a new function, setup_temp_super(), to setup temporary super
> for make_btrfs_v2().
>
> Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
> Signed-off-by: David Sterba <dsterba@xxxxxxxx>
> ---
> utils.c | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 117 insertions(+)
>
> diff --git a/utils.c b/utils.c
> index bc10293..ed5476d 100644
> --- a/utils.c
> +++ b/utils.c
> @@ -212,6 +212,98 @@ 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 allocation 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 btrfs will only has 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(super->label, cfg->label, BTRFS_LABEL_SIZE - 1);
Why not use __strncpy_null?
Thanks,
-liubo
> +
> + /* 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().
> *
> @@ -230,6 +322,10 @@ 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 */
> @@ -260,6 +356,27 @@ static int make_convert_btrfs(int fd, struct btrfs_mkfs_config *cfg,
> if (ret < 0)
> goto out;
>
> + /*
> + * Inside the allocate metadata chunk, its 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, its 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;
> }
> --
> 2.7.0
>
>
>
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