Btrfs progs v4.17.1

[btrfs-progs-unstable/devel.git] / mkfs / common.c

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <unistd.h>
#include <uuid/uuid.h>
#include <blkid/blkid.h>
#include <fcntl.h>
#include <limits.h>
#include "ctree.h"
#include "disk-io.h"
#include "volumes.h"
#include "utils.h"
#include "mkfs/common.h"

static u64 reference_root_table[] = {
        [1] =   BTRFS_ROOT_TREE_OBJECTID,
        [2] =   BTRFS_EXTENT_TREE_OBJECTID,
        [3] =   BTRFS_CHUNK_TREE_OBJECTID,
        [4] =   BTRFS_DEV_TREE_OBJECTID,
        [5] =   BTRFS_FS_TREE_OBJECTID,
        [6] =   BTRFS_CSUM_TREE_OBJECTID,
};

static int btrfs_create_tree_root(int fd, struct btrfs_mkfs_config *cfg,
                        struct extent_buffer *buf)
{
        struct btrfs_root_item root_item;
        struct btrfs_inode_item *inode_item;
        struct btrfs_disk_key disk_key;
        u32 nritems = 0;
        u32 itemoff;
        int ret = 0;
        int blk;
        u8 uuid[BTRFS_UUID_SIZE];

        memset(buf->data + sizeof(struct btrfs_header), 0,
                cfg->nodesize - sizeof(struct btrfs_header));
        memset(&root_item, 0, sizeof(root_item));
        memset(&disk_key, 0, sizeof(disk_key));

        /* create the items for the root tree */
        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_disk_key_type(&disk_key, BTRFS_ROOT_ITEM_KEY);
        btrfs_set_disk_key_offset(&disk_key, 0);
        itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize) - sizeof(root_item);

        for (blk = 0; blk < MKFS_BLOCK_COUNT; blk++) {
                if (blk == MKFS_SUPER_BLOCK || blk == MKFS_ROOT_TREE
                    || blk == MKFS_CHUNK_TREE)
                        continue;

                btrfs_set_root_bytenr(&root_item, cfg->blocks[blk]);
                btrfs_set_disk_key_objectid(&disk_key,
                        reference_root_table[blk]);
                btrfs_set_item_key(buf, &disk_key, nritems);
                btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
                btrfs_set_item_size(buf, btrfs_item_nr(nritems),
                                sizeof(root_item));
                if (blk == MKFS_FS_TREE) {
                        time_t now = time(NULL);

                        uuid_generate(uuid);
                        memcpy(root_item.uuid, uuid, BTRFS_UUID_SIZE);
                        btrfs_set_stack_timespec_sec(&root_item.otime, now);
                        btrfs_set_stack_timespec_sec(&root_item.ctime, now);
                } else {
                        memset(uuid, 0, BTRFS_UUID_SIZE);
                        memcpy(root_item.uuid, uuid, BTRFS_UUID_SIZE);
                        btrfs_set_stack_timespec_sec(&root_item.otime, 0);
                        btrfs_set_stack_timespec_sec(&root_item.ctime, 0);
                }
                write_extent_buffer(buf, &root_item,
                        btrfs_item_ptr_offset(buf, nritems),
                        sizeof(root_item));
                nritems++;
                itemoff -= sizeof(root_item);
        }

        /* generate checksum */
        csum_tree_block_size(buf, btrfs_csum_sizes[BTRFS_CSUM_TYPE_CRC32], 0);

        /* write back root tree */
        ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[MKFS_ROOT_TREE]);
        if (ret != cfg->nodesize)
                return (ret < 0 ? -errno : -EIO);

        return ret;
}

/*
 * @fs_uuid - if NULL, generates a UUID, returns back the new filesystem UUID
 *
 * The superblock signature is not valid, denotes a partially created
 * filesystem, needs to be finalized.
 *
 * The temporary fs will have the following chunk layout:
 * Device extent:
 * 0            1M                              5M      ......
 * | Reserved   | dev extent for SYS chunk      |
 *
 * And chunk mapping will be:
 * Chunk mapping:
 * 0            1M                              5M
 * |            | System chunk, 1:1 mapped      |
 *
 * That's to say, there will only be *ONE* system chunk, mapped to
 * [1M, 5M) physical offset.
 * And the only chunk is also in logical address [1M, 5M), containing
 * all essential tree blocks.
 */
int make_btrfs(int fd, struct btrfs_mkfs_config *cfg)
{
        struct btrfs_super_block super;
        struct extent_buffer *buf;
        struct btrfs_disk_key disk_key;
        struct btrfs_extent_item *extent_item;
        struct btrfs_chunk *chunk;
        struct btrfs_dev_item *dev_item;
        struct btrfs_dev_extent *dev_extent;
        u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
        u8 *ptr;
        int i;
        int ret;
        u32 itemoff;
        u32 nritems = 0;
        u64 first_free;
        u64 ref_root;
        u32 array_size;
        u32 item_size;
        int skinny_metadata = !!(cfg->features &
                                 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);
        u64 num_bytes;

        buf = malloc(sizeof(*buf) + max(cfg->sectorsize, cfg->nodesize));
        if (!buf)
                return -ENOMEM;

        first_free = BTRFS_SUPER_INFO_OFFSET + cfg->sectorsize * 2 - 1;
        first_free &= ~((u64)cfg->sectorsize - 1);

        memset(&super, 0, sizeof(super));

        num_bytes = (cfg->num_bytes / cfg->sectorsize) * cfg->sectorsize;
        if (*cfg->fs_uuid) {
                if (uuid_parse(cfg->fs_uuid, super.fsid) != 0) {
                        error("cannot 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 = -EBUSY;
                        goto out;
                }
        } else {
                uuid_generate(super.fsid);
                uuid_unparse(super.fsid, cfg->fs_uuid);
        }
        uuid_generate(super.dev_item.uuid);
        uuid_generate(chunk_tree_uuid);

        cfg->blocks[MKFS_SUPER_BLOCK] = BTRFS_SUPER_INFO_OFFSET;
        for (i = 1; i < MKFS_BLOCK_COUNT; i++) {
                cfg->blocks[i] = BTRFS_BLOCK_RESERVED_1M_FOR_SUPER +
                        cfg->nodesize * (i - 1);
        }

        btrfs_set_super_bytenr(&super, cfg->blocks[MKFS_SUPER_BLOCK]);
        btrfs_set_super_num_devices(&super, 1);
        btrfs_set_super_magic(&super, BTRFS_MAGIC_TEMPORARY);
        btrfs_set_super_generation(&super, 1);
        btrfs_set_super_root(&super, cfg->blocks[MKFS_ROOT_TREE]);
        btrfs_set_super_chunk_root(&super, cfg->blocks[MKFS_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);
        super.__unused_leafsize = cpu_to_le32(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_generation(&super, 1);
        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);

        /* create the tree of root objects */
        memset(buf->data, 0, cfg->nodesize);
        buf->len = cfg->nodesize;
        btrfs_set_header_bytenr(buf, cfg->blocks[MKFS_ROOT_TREE]);
        btrfs_set_header_nritems(buf, 4);
        btrfs_set_header_generation(buf, 1);
        btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
        btrfs_set_header_owner(buf, BTRFS_ROOT_TREE_OBJECTID);
        write_extent_buffer(buf, super.fsid, btrfs_header_fsid(),
                            BTRFS_FSID_SIZE);

        write_extent_buffer(buf, chunk_tree_uuid,
                            btrfs_header_chunk_tree_uuid(buf),
                            BTRFS_UUID_SIZE);

        ret = btrfs_create_tree_root(fd, cfg, buf);
        if (ret < 0)
                goto out;

        /* create the items for the extent tree */
        memset(buf->data + sizeof(struct btrfs_header), 0,
                cfg->nodesize - sizeof(struct btrfs_header));
        nritems = 0;
        itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize);
        for (i = 1; i < MKFS_BLOCK_COUNT; i++) {
                item_size = sizeof(struct btrfs_extent_item);
                if (!skinny_metadata)
                        item_size += sizeof(struct btrfs_tree_block_info);

                if (cfg->blocks[i] < first_free) {
                        error("block[%d] below first free: %llu < %llu",
                                        i, (unsigned long long)cfg->blocks[i],
                                        (unsigned long long)first_free);
                        ret = -EINVAL;
                        goto out;
                }
                if (cfg->blocks[i] < cfg->blocks[i - 1]) {
                        error("blocks %d and %d in reverse order: %llu < %llu",
                                i, i - 1,
                                (unsigned long long)cfg->blocks[i],
                                (unsigned long long)cfg->blocks[i - 1]);
                        ret = -EINVAL;
                        goto out;
                }

                /* create extent item */
                itemoff -= item_size;
                btrfs_set_disk_key_objectid(&disk_key, cfg->blocks[i]);
                if (skinny_metadata) {
                        btrfs_set_disk_key_type(&disk_key,
                                                BTRFS_METADATA_ITEM_KEY);
                        btrfs_set_disk_key_offset(&disk_key, 0);
                } else {
                        btrfs_set_disk_key_type(&disk_key,
                                                BTRFS_EXTENT_ITEM_KEY);
                        btrfs_set_disk_key_offset(&disk_key, cfg->nodesize);
                }
                btrfs_set_item_key(buf, &disk_key, nritems);
                btrfs_set_item_offset(buf, btrfs_item_nr(nritems),
                                      itemoff);
                btrfs_set_item_size(buf, btrfs_item_nr(nritems),
                                    item_size);
                extent_item = btrfs_item_ptr(buf, nritems,
                                             struct btrfs_extent_item);
                btrfs_set_extent_refs(buf, extent_item, 1);
                btrfs_set_extent_generation(buf, extent_item, 1);
                btrfs_set_extent_flags(buf, extent_item,
                                       BTRFS_EXTENT_FLAG_TREE_BLOCK);
                nritems++;

                /* create extent ref */
                ref_root = reference_root_table[i];
                btrfs_set_disk_key_objectid(&disk_key, cfg->blocks[i]);
                btrfs_set_disk_key_offset(&disk_key, ref_root);
                btrfs_set_disk_key_type(&disk_key, BTRFS_TREE_BLOCK_REF_KEY);
                btrfs_set_item_key(buf, &disk_key, nritems);
                btrfs_set_item_offset(buf, btrfs_item_nr(nritems),
                                      itemoff);
                btrfs_set_item_size(buf, btrfs_item_nr(nritems), 0);
                nritems++;
        }
        btrfs_set_header_bytenr(buf, cfg->blocks[MKFS_EXTENT_TREE]);
        btrfs_set_header_owner(buf, BTRFS_EXTENT_TREE_OBJECTID);
        btrfs_set_header_nritems(buf, nritems);
        csum_tree_block_size(buf, btrfs_csum_sizes[BTRFS_CSUM_TYPE_CRC32], 0);
        ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[MKFS_EXTENT_TREE]);
        if (ret != cfg->nodesize) {
                ret = (ret < 0 ? -errno : -EIO);
                goto out;
        }

        /* create the chunk tree */
        memset(buf->data + sizeof(struct btrfs_header), 0,
                cfg->nodesize - sizeof(struct btrfs_header));
        nritems = 0;
        item_size = sizeof(*dev_item);
        itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize) - item_size;

        /* first device 1 (there is no device 0) */
        btrfs_set_disk_key_objectid(&disk_key, BTRFS_DEV_ITEMS_OBJECTID);
        btrfs_set_disk_key_offset(&disk_key, 1);
        btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_ITEM_KEY);
        btrfs_set_item_key(buf, &disk_key, nritems);
        btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
        btrfs_set_item_size(buf, btrfs_item_nr(nritems), item_size);

        dev_item = btrfs_item_ptr(buf, nritems, struct btrfs_dev_item);
        btrfs_set_device_id(buf, dev_item, 1);
        btrfs_set_device_generation(buf, dev_item, 0);
        btrfs_set_device_total_bytes(buf, dev_item, num_bytes);
        btrfs_set_device_bytes_used(buf, dev_item,
                                    BTRFS_MKFS_SYSTEM_GROUP_SIZE);
        btrfs_set_device_io_align(buf, dev_item, cfg->sectorsize);
        btrfs_set_device_io_width(buf, dev_item, cfg->sectorsize);
        btrfs_set_device_sector_size(buf, dev_item, cfg->sectorsize);
        btrfs_set_device_type(buf, dev_item, 0);

        write_extent_buffer(buf, super.dev_item.uuid,
                            (unsigned long)btrfs_device_uuid(dev_item),
                            BTRFS_UUID_SIZE);
        write_extent_buffer(buf, super.fsid,
                            (unsigned long)btrfs_device_fsid(dev_item),
                            BTRFS_UUID_SIZE);
        read_extent_buffer(buf, &super.dev_item, (unsigned long)dev_item,
                           sizeof(*dev_item));

        nritems++;
        item_size = btrfs_chunk_item_size(1);
        itemoff = itemoff - item_size;

        /* then we have chunk 0 */
        btrfs_set_disk_key_objectid(&disk_key, BTRFS_FIRST_CHUNK_TREE_OBJECTID);
        btrfs_set_disk_key_offset(&disk_key, BTRFS_BLOCK_RESERVED_1M_FOR_SUPER);
        btrfs_set_disk_key_type(&disk_key, BTRFS_CHUNK_ITEM_KEY);
        btrfs_set_item_key(buf, &disk_key, nritems);
        btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
        btrfs_set_item_size(buf, btrfs_item_nr(nritems), item_size);

        chunk = btrfs_item_ptr(buf, nritems, struct btrfs_chunk);
        btrfs_set_chunk_length(buf, chunk, BTRFS_MKFS_SYSTEM_GROUP_SIZE);
        btrfs_set_chunk_owner(buf, chunk, BTRFS_EXTENT_TREE_OBJECTID);
        btrfs_set_chunk_stripe_len(buf, chunk, BTRFS_STRIPE_LEN);
        btrfs_set_chunk_type(buf, chunk, BTRFS_BLOCK_GROUP_SYSTEM);
        btrfs_set_chunk_io_align(buf, chunk, cfg->sectorsize);
        btrfs_set_chunk_io_width(buf, chunk, cfg->sectorsize);
        btrfs_set_chunk_sector_size(buf, chunk, cfg->sectorsize);
        btrfs_set_chunk_num_stripes(buf, chunk, 1);
        btrfs_set_stripe_devid_nr(buf, chunk, 0, 1);
        btrfs_set_stripe_offset_nr(buf, chunk, 0,
                                   BTRFS_BLOCK_RESERVED_1M_FOR_SUPER);
        nritems++;

        write_extent_buffer(buf, super.dev_item.uuid,
                            (unsigned long)btrfs_stripe_dev_uuid(&chunk->stripe),
                            BTRFS_UUID_SIZE);

        /* copy the key for the chunk to the system array */
        ptr = super.sys_chunk_array;
        array_size = sizeof(disk_key);

        memcpy(ptr, &disk_key, sizeof(disk_key));
        ptr += sizeof(disk_key);

        /* copy the chunk to the system array */
        read_extent_buffer(buf, ptr, (unsigned long)chunk, item_size);
        array_size += item_size;
        ptr += item_size;
        btrfs_set_super_sys_array_size(&super, array_size);

        btrfs_set_header_bytenr(buf, cfg->blocks[MKFS_CHUNK_TREE]);
        btrfs_set_header_owner(buf, BTRFS_CHUNK_TREE_OBJECTID);
        btrfs_set_header_nritems(buf, nritems);
        csum_tree_block_size(buf, btrfs_csum_sizes[BTRFS_CSUM_TYPE_CRC32], 0);
        ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[MKFS_CHUNK_TREE]);
        if (ret != cfg->nodesize) {
                ret = (ret < 0 ? -errno : -EIO);
                goto out;
        }

        /* create the device tree */
        memset(buf->data + sizeof(struct btrfs_header), 0,
                cfg->nodesize - sizeof(struct btrfs_header));
        nritems = 0;
        itemoff = __BTRFS_LEAF_DATA_SIZE(cfg->nodesize) -
                sizeof(struct btrfs_dev_extent);

        btrfs_set_disk_key_objectid(&disk_key, 1);
        btrfs_set_disk_key_offset(&disk_key, BTRFS_BLOCK_RESERVED_1M_FOR_SUPER);
        btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_EXTENT_KEY);
        btrfs_set_item_key(buf, &disk_key, nritems);
        btrfs_set_item_offset(buf, btrfs_item_nr(nritems), itemoff);
        btrfs_set_item_size(buf, btrfs_item_nr(nritems),
                            sizeof(struct btrfs_dev_extent));
        dev_extent = btrfs_item_ptr(buf, nritems, struct btrfs_dev_extent);
        btrfs_set_dev_extent_chunk_tree(buf, dev_extent,
                                        BTRFS_CHUNK_TREE_OBJECTID);
        btrfs_set_dev_extent_chunk_objectid(buf, dev_extent,
                                        BTRFS_FIRST_CHUNK_TREE_OBJECTID);
        btrfs_set_dev_extent_chunk_offset(buf, dev_extent,
                                          BTRFS_BLOCK_RESERVED_1M_FOR_SUPER);

        write_extent_buffer(buf, chunk_tree_uuid,
                    (unsigned long)btrfs_dev_extent_chunk_tree_uuid(dev_extent),
                    BTRFS_UUID_SIZE);

        btrfs_set_dev_extent_length(buf, dev_extent,
                                    BTRFS_MKFS_SYSTEM_GROUP_SIZE);
        nritems++;

        btrfs_set_header_bytenr(buf, cfg->blocks[MKFS_DEV_TREE]);
        btrfs_set_header_owner(buf, BTRFS_DEV_TREE_OBJECTID);
        btrfs_set_header_nritems(buf, nritems);
        csum_tree_block_size(buf, btrfs_csum_sizes[BTRFS_CSUM_TYPE_CRC32], 0);
        ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[MKFS_DEV_TREE]);
        if (ret != cfg->nodesize) {
                ret = (ret < 0 ? -errno : -EIO);
                goto out;
        }

        /* 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[MKFS_FS_TREE]);
        btrfs_set_header_owner(buf, BTRFS_FS_TREE_OBJECTID);
        btrfs_set_header_nritems(buf, 0);
        csum_tree_block_size(buf, btrfs_csum_sizes[BTRFS_CSUM_TYPE_CRC32], 0);
        ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[MKFS_FS_TREE]);
        if (ret != cfg->nodesize) {
                ret = (ret < 0 ? -errno : -EIO);
                goto out;
        }
        /* 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[MKFS_CSUM_TREE]);
        btrfs_set_header_owner(buf, BTRFS_CSUM_TREE_OBJECTID);
        btrfs_set_header_nritems(buf, 0);
        csum_tree_block_size(buf, btrfs_csum_sizes[BTRFS_CSUM_TYPE_CRC32], 0);
        ret = pwrite(fd, buf->data, cfg->nodesize, cfg->blocks[MKFS_CSUM_TREE]);
        if (ret != cfg->nodesize) {
                ret = (ret < 0 ? -errno : -EIO);
                goto out;
        }

        /* and write out the super block */
        memset(buf->data, 0, BTRFS_SUPER_INFO_SIZE);
        memcpy(buf->data, &super, sizeof(super));
        buf->len = BTRFS_SUPER_INFO_SIZE;
        csum_tree_block_size(buf, btrfs_csum_sizes[BTRFS_CSUM_TYPE_CRC32], 0);
        ret = pwrite(fd, buf->data, BTRFS_SUPER_INFO_SIZE,
                        cfg->blocks[MKFS_SUPER_BLOCK]);
        if (ret != BTRFS_SUPER_INFO_SIZE) {
                ret = (ret < 0 ? -errno : -EIO);
                goto out;
        }

        ret = 0;

out:
        free(buf);
        return ret;
}

/*
 * Btrfs minimum size calculation is complicated, it should include at least:
 * 1. system group size
 * 2. minimum global block reserve
 * 3. metadata used at mkfs
 * 4. space reservation to create uuid for first mount.
 * Also, raid factor should also be taken into consideration.
 * To avoid the overkill calculation, (system group + global block rsv) * 2
 * for *EACH* device should be good enough.
 */
static u64 btrfs_min_global_blk_rsv_size(u32 nodesize)
{
        return (u64)nodesize << 10;
}

u64 btrfs_min_dev_size(u32 nodesize, int mixed, u64 meta_profile,
                       u64 data_profile)
{
        u64 reserved = 0;
        u64 meta_size;
        u64 data_size;

        if (mixed)
                return 2 * (BTRFS_MKFS_SYSTEM_GROUP_SIZE +
                            btrfs_min_global_blk_rsv_size(nodesize));

        /*
         * Minimal size calculation is complex due to several factors:
         * 0) Reserved 1M range.
         *
         * 1) Temporary chunk reuse
         *    If specified chunk profile is SINGLE, we can reuse
         *    temporary chunks, no need to allocate new chunks.
         *
         * 2) Different minimal chunk size for different profiles:
         *    For initial sys chunk, chunk size is fixed to 4M.
         *    For single profile, minimal chunk size is 8M for all.
         *    For other profiles, minimal chunk and stripe size ranges from 8M
         *    to 64M.
         *
         * To calculate it a little easier, here we assume we don't reuse any
         * temporary chunk, and calculate the size completely by ourselves.
         *
         * Temporary chunks sizes are always fixed:
         * One initial sys chunk, one SINGLE meta, and one SINGLE data.
         * The latter two are all 8M, according to @calc_size of
         * btrfs_alloc_chunk().
         */
        reserved += BTRFS_BLOCK_RESERVED_1M_FOR_SUPER +
                    BTRFS_MKFS_SYSTEM_GROUP_SIZE + SZ_8M * 2;

        /*
         * For real chunks, we need to select different sizes:
         * For SINGLE, it's still fixed to 8M (@calc_size).
         * For other profiles, refer to max(@min_stripe_size, @calc_size).
         *
         * And use the stripe size to calculate its physical used space.
         */
        if (meta_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK)
                meta_size = SZ_8M + SZ_32M;
        else
                meta_size = SZ_8M + SZ_8M;
        /* For DUP/metadata,  2 stripes on one disk */
        if (meta_profile & BTRFS_BLOCK_GROUP_DUP)
                meta_size *= 2;
        reserved += meta_size;

        if (data_profile & BTRFS_BLOCK_GROUP_PROFILE_MASK)
                data_size = SZ_64M;
        else
                data_size = SZ_8M;
        /* For DUP/data,  2 stripes on one disk */
        if (data_profile & BTRFS_BLOCK_GROUP_DUP)
                data_size *= 2;
        reserved += data_size;

        return reserved;
}

#define isoctal(c)      (((c) & ~7) == '0')

static inline void translate(char *f, char *t)
{
        while (*f != '\0') {
                if (*f == '\\' &&
                    isoctal(f[1]) && isoctal(f[2]) && isoctal(f[3])) {
                        *t++ = 64*(f[1] & 7) + 8*(f[2] & 7) + (f[3] & 7);
                        f += 4;
                } else
                        *t++ = *f++;
        }
        *t = '\0';
        return;
}

/*
 * Checks if the swap device.
 * Returns 1 if swap device, < 0 on error or 0 if not swap device.
 */
static int is_swap_device(const char *file)
{
        FILE    *f;
        struct stat     st_buf;
        dev_t   dev;
        ino_t   ino = 0;
        char    tmp[PATH_MAX];
        char    buf[PATH_MAX];
        char    *cp;
        int     ret = 0;

        if (stat(file, &st_buf) < 0)
                return -errno;
        if (S_ISBLK(st_buf.st_mode))
                dev = st_buf.st_rdev;
        else if (S_ISREG(st_buf.st_mode)) {
                dev = st_buf.st_dev;
                ino = st_buf.st_ino;
        } else
                return 0;

        if ((f = fopen("/proc/swaps", "r")) == NULL)
                return 0;

        /* skip the first line */
        if (fgets(tmp, sizeof(tmp), f) == NULL)
                goto out;

        while (fgets(tmp, sizeof(tmp), f) != NULL) {
                if ((cp = strchr(tmp, ' ')) != NULL)
                        *cp = '\0';
                if ((cp = strchr(tmp, '\t')) != NULL)
                        *cp = '\0';
                translate(tmp, buf);
                if (stat(buf, &st_buf) != 0)
                        continue;
                if (S_ISBLK(st_buf.st_mode)) {
                        if (dev == st_buf.st_rdev) {
                                ret = 1;
                                break;
                        }
                } else if (S_ISREG(st_buf.st_mode)) {
                        if (dev == st_buf.st_dev && ino == st_buf.st_ino) {
                                ret = 1;
                                break;
                        }
                }
        }

out:
        fclose(f);

        return ret;
}

/*
 * Check for existing filesystem or partition table on device.
 * Returns:
 *       1 for existing fs or partition
 *       0 for nothing found
 *      -1 for internal error
 */
static int check_overwrite(const char *device)
{
        const char      *type;
        blkid_probe     pr = NULL;
        int             ret;
        blkid_loff_t    size;

        if (!device || !*device)
                return 0;

        ret = -1; /* will reset on success of all setup calls */

        pr = blkid_new_probe_from_filename(device);
        if (!pr)
                goto out;

        size = blkid_probe_get_size(pr);
        if (size < 0)
                goto out;

        /* nothing to overwrite on a 0-length device */
        if (size == 0) {
                ret = 0;
                goto out;
        }

        ret = blkid_probe_enable_partitions(pr, 1);
        if (ret < 0)
                goto out;

        ret = blkid_do_fullprobe(pr);
        if (ret < 0)
                goto out;

        /*
         * Blkid returns 1 for nothing found and 0 when it finds a signature,
         * but we want the exact opposite, so reverse the return value here.
         *
         * In addition print some useful diagnostics about what actually is
         * on the device.
         */
        if (ret) {
                ret = 0;
                goto out;
        }

        if (!blkid_probe_lookup_value(pr, "TYPE", &type, NULL)) {
                fprintf(stderr,
                        "%s appears to contain an existing "
                        "filesystem (%s).\n", device, type);
        } else if (!blkid_probe_lookup_value(pr, "PTTYPE", &type, NULL)) {
                fprintf(stderr,
                        "%s appears to contain a partition "
                        "table (%s).\n", device, type);
        } else {
                fprintf(stderr,
                        "%s appears to contain something weird "
                        "according to blkid\n", device);
        }
        ret = 1;

out:
        if (pr)
                blkid_free_probe(pr);
        if (ret == -1)
                fprintf(stderr,
                        "probe of %s failed, cannot detect "
                          "existing filesystem.\n", device);
        return ret;
}

/*
 * Check if a device is suitable for btrfs
 * returns:
 *  1: something is wrong, an error is printed
 *  0: all is fine
 */
int test_dev_for_mkfs(const char *file, int force_overwrite)
{
        int ret, fd;
        struct stat st;

        ret = is_swap_device(file);
        if (ret < 0) {
                error("checking status of %s: %s", file, strerror(-ret));
                return 1;
        }
        if (ret == 1) {
                error("%s is a swap device", file);
                return 1;
        }
        ret = test_status_for_mkfs(file, force_overwrite);
        if (ret)
                return 1;
        /* check if the device is busy */
        fd = open(file, O_RDWR|O_EXCL);
        if (fd < 0) {
                error("unable to open %s: %m", file);
                return 1;
        }
        if (fstat(fd, &st)) {
                error("unable to stat %s: %m", file);
                close(fd);
                return 1;
        }
        if (!S_ISBLK(st.st_mode)) {
                error("%s is not a block device", file);
                close(fd);
                return 1;
        }
        close(fd);
        return 0;
}

/*
 * check if the file (device) is formatted or mounted
 */
int test_status_for_mkfs(const char *file, bool force_overwrite)
{
        int ret;

        if (!force_overwrite) {
                if (check_overwrite(file)) {
                        error("use the -f option to force overwrite of %s",
                                        file);
                        return 1;
                }
        }
        ret = check_mounted(file);
        if (ret < 0) {
                error("cannot check mount status of %s: %s", file,
                                strerror(-ret));
                return 1;
        }
        if (ret == 1) {
                error("%s is mounted", file);
                return 1;
        }

        return 0;
}

int is_vol_small(const char *file)
{
        int fd = -1;
        int e;
        struct stat st;
        u64 size;

        fd = open(file, O_RDONLY);
        if (fd < 0)
                return -errno;
        if (fstat(fd, &st) < 0) {
                e = -errno;
                close(fd);
                return e;
        }
        size = btrfs_device_size(fd, &st);
        if (size == 0) {
                close(fd);
                return -1;
        }
        if (size < BTRFS_MKFS_SMALL_VOLUME_SIZE) {
                close(fd);
                return 1;
        } else {
                close(fd);
                return 0;
        }
}

int test_minimum_size(const char *file, u64 min_dev_size)
{
        int fd;
        struct stat statbuf;

        fd = open(file, O_RDONLY);
        if (fd < 0)
                return -errno;
        if (stat(file, &statbuf) < 0) {
                close(fd);
                return -errno;
        }
        if (btrfs_device_size(fd, &statbuf) < min_dev_size) {
                close(fd);
                return 1;
        }
        close(fd);
        return 0;
}