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[btrfs-progs-unstable/devel.git] / utils.c

/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 * Copyright (C) 2008 Morey Roof.  All rights reserved.
 *
 * 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.
 */

#define _XOPEN_SOURCE 700
#define __USE_XOPEN2K8
#define __XOPEN2K8 /* due to an error in dirent.h, to get dirfd() */
#define _GNU_SOURCE     /* O_NOATIME */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <uuid/uuid.h>
#include <fcntl.h>
#include <unistd.h>
#include <mntent.h>
#include <ctype.h>
#include <linux/loop.h>
#include <linux/major.h>
#include <linux/kdev_t.h>
#include <limits.h>
#include <blkid/blkid.h>
#include "kerncompat.h"
#include "radix-tree.h"
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "crc32c.h"
#include "utils.h"
#include "volumes.h"
#include "ioctl.h"

#ifndef BLKDISCARD
#define BLKDISCARD      _IO(0x12,119)
#endif

/*
 * Discard the given range in one go
 */
static int discard_range(int fd, u64 start, u64 len)
{
        u64 range[2] = { start, len };

        if (ioctl(fd, BLKDISCARD, &range) < 0)
                return errno;
        return 0;
}

/*
 * Discard blocks in the given range in 1G chunks, the process is interruptible
 */
static int discard_blocks(int fd, u64 start, u64 len)
{
        while (len > 0) {
                /* 1G granularity */
                u64 chunk_size = min_t(u64, len, 1*1024*1024*1024);
                int ret;

                ret = discard_range(fd, start, chunk_size);
                if (ret)
                        return ret;
                len -= chunk_size;
                start += chunk_size;
        }

        return 0;
}

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,
};

int make_btrfs(int fd, const char *device, const char *label,
               u64 blocks[7], u64 num_bytes, u32 nodesize,
               u32 leafsize, u32 sectorsize, u32 stripesize, u64 features)
{
        struct btrfs_super_block super;
        struct extent_buffer *buf;
        struct btrfs_root_item root_item;
        struct btrfs_disk_key disk_key;
        struct btrfs_extent_item *extent_item;
        struct btrfs_inode_item *inode_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 = !!(features &
                                 BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA);

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

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

        num_bytes = (num_bytes / sectorsize) * sectorsize;
        uuid_generate(super.fsid);
        uuid_generate(super.dev_item.uuid);
        uuid_generate(chunk_tree_uuid);

        btrfs_set_super_bytenr(&super, blocks[0]);
        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, blocks[1]);
        btrfs_set_super_chunk_root(&super, blocks[3]);
        btrfs_set_super_total_bytes(&super, num_bytes);
        btrfs_set_super_bytes_used(&super, 6 * leafsize);
        btrfs_set_super_sectorsize(&super, sectorsize);
        btrfs_set_super_leafsize(&super, leafsize);
        btrfs_set_super_nodesize(&super, nodesize);
        btrfs_set_super_stripesize(&super, 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, features);
        if (label)
                strncpy(super.label, label, BTRFS_LABEL_SIZE - 1);

        buf = malloc(sizeof(*buf) + max(sectorsize, leafsize));

        /* create the tree of root objects */
        memset(buf->data, 0, leafsize);
        buf->len = leafsize;
        btrfs_set_header_bytenr(buf, blocks[1]);
        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);

        /* create the items for the root tree */
        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, leafsize);
        btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
        btrfs_set_root_refs(&root_item, 1);
        btrfs_set_root_used(&root_item, leafsize);
        btrfs_set_root_generation(&root_item, 1);

        memset(&disk_key, 0, sizeof(disk_key));
        btrfs_set_disk_key_type(&disk_key, BTRFS_ROOT_ITEM_KEY);
        btrfs_set_disk_key_offset(&disk_key, 0);
        nritems = 0;

        itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize) - sizeof(root_item);
        btrfs_set_root_bytenr(&root_item, blocks[2]);
        btrfs_set_disk_key_objectid(&disk_key, BTRFS_EXTENT_TREE_OBJECTID);
        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));
        write_extent_buffer(buf, &root_item, btrfs_item_ptr_offset(buf,
                            nritems), sizeof(root_item));
        nritems++;

        itemoff = itemoff - sizeof(root_item);
        btrfs_set_root_bytenr(&root_item, blocks[4]);
        btrfs_set_disk_key_objectid(&disk_key, BTRFS_DEV_TREE_OBJECTID);
        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));
        write_extent_buffer(buf, &root_item,
                            btrfs_item_ptr_offset(buf, nritems),
                            sizeof(root_item));
        nritems++;

        itemoff = itemoff - sizeof(root_item);
        btrfs_set_root_bytenr(&root_item, blocks[5]);
        btrfs_set_disk_key_objectid(&disk_key, BTRFS_FS_TREE_OBJECTID);
        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));
        write_extent_buffer(buf, &root_item,
                            btrfs_item_ptr_offset(buf, nritems),
                            sizeof(root_item));
        nritems++;

        itemoff = itemoff - sizeof(root_item);
        btrfs_set_root_bytenr(&root_item, blocks[6]);
        btrfs_set_disk_key_objectid(&disk_key, BTRFS_CSUM_TREE_OBJECTID);
        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));
        write_extent_buffer(buf, &root_item,
                            btrfs_item_ptr_offset(buf, nritems),
                            sizeof(root_item));
        nritems++;


        csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
        ret = pwrite(fd, buf->data, leafsize, blocks[1]);
        if (ret != leafsize) {
                ret = (ret < 0 ? -errno : -EIO);
                goto out;
        }

        /* create the items for the extent tree */
        memset(buf->data+sizeof(struct btrfs_header), 0,
                leafsize-sizeof(struct btrfs_header));
        nritems = 0;
        itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize);
        for (i = 1; i < 7; i++) {
                item_size = sizeof(struct btrfs_extent_item);
                if (!skinny_metadata)
                        item_size += sizeof(struct btrfs_tree_block_info);

                BUG_ON(blocks[i] < first_free);
                BUG_ON(blocks[i] < blocks[i - 1]);

                /* create extent item */
                itemoff -= item_size;
                btrfs_set_disk_key_objectid(&disk_key, 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, leafsize);
                }
                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, 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, blocks[2]);
        btrfs_set_header_owner(buf, BTRFS_EXTENT_TREE_OBJECTID);
        btrfs_set_header_nritems(buf, nritems);
        csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
        ret = pwrite(fd, buf->data, leafsize, blocks[2]);
        if (ret != leafsize) {
                ret = (ret < 0 ? -errno : -EIO);
                goto out;
        }

        /* create the chunk tree */
        memset(buf->data+sizeof(struct btrfs_header), 0,
                leafsize-sizeof(struct btrfs_header));
        nritems = 0;
        item_size = sizeof(*dev_item);
        itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize) - 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, sectorsize);
        btrfs_set_device_io_width(buf, dev_item, sectorsize);
        btrfs_set_device_sector_size(buf, dev_item, 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, 0);
        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, 64 * 1024);
        btrfs_set_chunk_type(buf, chunk, BTRFS_BLOCK_GROUP_SYSTEM);
        btrfs_set_chunk_io_align(buf, chunk, sectorsize);
        btrfs_set_chunk_io_width(buf, chunk, sectorsize);
        btrfs_set_chunk_sector_size(buf, chunk, 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, 0);
        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, blocks[3]);
        btrfs_set_header_owner(buf, BTRFS_CHUNK_TREE_OBJECTID);
        btrfs_set_header_nritems(buf, nritems);
        csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
        ret = pwrite(fd, buf->data, leafsize, blocks[3]);
        if (ret != leafsize) {
                ret = (ret < 0 ? -errno : -EIO);
                goto out;
        }

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

        btrfs_set_disk_key_objectid(&disk_key, 1);
        btrfs_set_disk_key_offset(&disk_key, 0);
        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, 0);

        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, blocks[4]);
        btrfs_set_header_owner(buf, BTRFS_DEV_TREE_OBJECTID);
        btrfs_set_header_nritems(buf, nritems);
        csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
        ret = pwrite(fd, buf->data, leafsize, blocks[4]);
        if (ret != leafsize) {
                ret = (ret < 0 ? -errno : -EIO);
                goto out;
        }

        /* create the FS root */
        memset(buf->data+sizeof(struct btrfs_header), 0,
                leafsize-sizeof(struct btrfs_header));
        btrfs_set_header_bytenr(buf, blocks[5]);
        btrfs_set_header_owner(buf, BTRFS_FS_TREE_OBJECTID);
        btrfs_set_header_nritems(buf, 0);
        csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
        ret = pwrite(fd, buf->data, leafsize, blocks[5]);
        if (ret != leafsize) {
                ret = (ret < 0 ? -errno : -EIO);
                goto out;
        }
        /* finally create the csum root */
        memset(buf->data+sizeof(struct btrfs_header), 0,
                leafsize-sizeof(struct btrfs_header));
        btrfs_set_header_bytenr(buf, blocks[6]);
        btrfs_set_header_owner(buf, BTRFS_CSUM_TREE_OBJECTID);
        btrfs_set_header_nritems(buf, 0);
        csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
        ret = pwrite(fd, buf->data, leafsize, blocks[6]);
        if (ret != leafsize) {
                ret = (ret < 0 ? -errno : -EIO);
                goto out;
        }

        /* and write out the super block */
        BUG_ON(sizeof(super) > sectorsize);
        memset(buf->data, 0, sectorsize);
        memcpy(buf->data, &super, sizeof(super));
        buf->len = sectorsize;
        csum_tree_block_size(buf, BTRFS_CRC32_SIZE, 0);
        ret = pwrite(fd, buf->data, sectorsize, blocks[0]);
        if (ret != sectorsize) {
                ret = (ret < 0 ? -errno : -EIO);
                goto out;
        }

        ret = 0;

out:
        free(buf);
        return ret;
}

u64 btrfs_device_size(int fd, struct stat *st)
{
        u64 size;
        if (S_ISREG(st->st_mode)) {
                return st->st_size;
        }
        if (!S_ISBLK(st->st_mode)) {
                return 0;
        }
        if (ioctl(fd, BLKGETSIZE64, &size) >= 0) {
                return size;
        }
        return 0;
}

static int zero_blocks(int fd, off_t start, size_t len)
{
        char *buf = malloc(len);
        int ret = 0;
        ssize_t written;

        if (!buf)
                return -ENOMEM;
        memset(buf, 0, len);
        written = pwrite(fd, buf, len, start);
        if (written != len)
                ret = -EIO;
        free(buf);
        return ret;
}

static int zero_dev_start(int fd)
{
        off_t start = 0;
        size_t len = 2 * 1024 * 1024;

#ifdef __sparc__
        /* don't overwrite the disk labels on sparc */
        start = 1024;
        len -= 1024;
#endif
        return zero_blocks(fd, start, len);
}

static int zero_dev_end(int fd, u64 dev_size)
{
        size_t len = 2 * 1024 * 1024;
        off_t start = dev_size - len;

        return zero_blocks(fd, start, len);
}

int btrfs_add_to_fsid(struct btrfs_trans_handle *trans,
                      struct btrfs_root *root, int fd, char *path,
                      u64 block_count, u32 io_width, u32 io_align,
                      u32 sectorsize)
{
        struct btrfs_super_block *disk_super;
        struct btrfs_super_block *super = root->fs_info->super_copy;
        struct btrfs_device *device;
        struct btrfs_dev_item *dev_item;
        char *buf;
        u64 total_bytes;
        u64 num_devs;
        int ret;

        device = kzalloc(sizeof(*device), GFP_NOFS);
        if (!device)
                return -ENOMEM;
        buf = kmalloc(sectorsize, GFP_NOFS);
        if (!buf) {
                kfree(device);
                return -ENOMEM;
        }
        BUG_ON(sizeof(*disk_super) > sectorsize);
        memset(buf, 0, sectorsize);

        disk_super = (struct btrfs_super_block *)buf;
        dev_item = &disk_super->dev_item;

        uuid_generate(device->uuid);
        device->devid = 0;
        device->type = 0;
        device->io_width = io_width;
        device->io_align = io_align;
        device->sector_size = sectorsize;
        device->fd = fd;
        device->writeable = 1;
        device->total_bytes = block_count;
        device->bytes_used = 0;
        device->total_ios = 0;
        device->dev_root = root->fs_info->dev_root;

        ret = btrfs_add_device(trans, root, device);
        BUG_ON(ret);

        total_bytes = btrfs_super_total_bytes(super) + block_count;
        btrfs_set_super_total_bytes(super, total_bytes);

        num_devs = btrfs_super_num_devices(super) + 1;
        btrfs_set_super_num_devices(super, num_devs);

        memcpy(disk_super, super, sizeof(*disk_super));

        printf("adding device %s id %llu\n", path,
               (unsigned long long)device->devid);

        btrfs_set_super_bytenr(disk_super, BTRFS_SUPER_INFO_OFFSET);
        btrfs_set_stack_device_id(dev_item, device->devid);
        btrfs_set_stack_device_type(dev_item, device->type);
        btrfs_set_stack_device_io_align(dev_item, device->io_align);
        btrfs_set_stack_device_io_width(dev_item, device->io_width);
        btrfs_set_stack_device_sector_size(dev_item, device->sector_size);
        btrfs_set_stack_device_total_bytes(dev_item, device->total_bytes);
        btrfs_set_stack_device_bytes_used(dev_item, device->bytes_used);
        memcpy(&dev_item->uuid, device->uuid, BTRFS_UUID_SIZE);

        ret = pwrite(fd, buf, sectorsize, BTRFS_SUPER_INFO_OFFSET);
        BUG_ON(ret != sectorsize);

        kfree(buf);
        list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
        device->fs_devices = root->fs_info->fs_devices;
        return 0;
}

int btrfs_prepare_device(int fd, char *file, int zero_end, u64 *block_count_ret,
                           u64 max_block_count, int *mixed, int discard)
{
        u64 block_count;
        u64 bytenr;
        struct stat st;
        int i, ret;

        ret = fstat(fd, &st);
        if (ret < 0) {
                fprintf(stderr, "unable to stat %s\n", file);
                return 1;
        }

        block_count = btrfs_device_size(fd, &st);
        if (block_count == 0) {
                fprintf(stderr, "unable to find %s size\n", file);
                return 1;
        }
        if (max_block_count)
                block_count = min(block_count, max_block_count);
        zero_end = 1;

        if (block_count < 1024 * 1024 * 1024 && !(*mixed)) {
                printf("SMALL VOLUME: forcing mixed metadata/data groups\n");
                *mixed = 1;
        }

        if (discard) {
                /*
                 * We intentionally ignore errors from the discard ioctl.  It
                 * is not necessary for the mkfs functionality but just an
                 * optimization.
                 */
                if (discard_blocks(fd, 0, 0) == 0) {
                        fprintf(stderr, "Performing full device TRIM (%s) ...\n",
                                pretty_size(block_count));
                        discard_blocks(fd, 0, block_count);
                }
        }

        ret = zero_dev_start(fd);
        if (ret)
                goto zero_dev_error;

        for (i = 0 ; i < BTRFS_SUPER_MIRROR_MAX; i++) {
                bytenr = btrfs_sb_offset(i);
                if (bytenr >= block_count)
                        break;
                ret = zero_blocks(fd, bytenr, BTRFS_SUPER_INFO_SIZE);
                if (ret)
                        goto zero_dev_error;
        }

        if (zero_end) {
                ret = zero_dev_end(fd, block_count);
                if (ret)
                        goto zero_dev_error;
        }
        *block_count_ret = block_count;

zero_dev_error:
        if (ret < 0) {
                fprintf(stderr, "ERROR: failed to zero device '%s' - %s\n",
                        file, strerror(-ret));
                return 1;
        } else if (ret > 0) {
                fprintf(stderr, "ERROR: failed to zero device '%s' - %d\n",
                        file, ret);
                return 1;
        }
        return 0;
}

int btrfs_make_root_dir(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root, u64 objectid)
{
        int ret;
        struct btrfs_inode_item inode_item;
        time_t now = time(NULL);

        memset(&inode_item, 0, sizeof(inode_item));
        btrfs_set_stack_inode_generation(&inode_item, trans->transid);
        btrfs_set_stack_inode_size(&inode_item, 0);
        btrfs_set_stack_inode_nlink(&inode_item, 1);
        btrfs_set_stack_inode_nbytes(&inode_item, root->leafsize);
        btrfs_set_stack_inode_mode(&inode_item, S_IFDIR | 0755);
        btrfs_set_stack_timespec_sec(&inode_item.atime, now);
        btrfs_set_stack_timespec_nsec(&inode_item.atime, 0);
        btrfs_set_stack_timespec_sec(&inode_item.ctime, now);
        btrfs_set_stack_timespec_nsec(&inode_item.ctime, 0);
        btrfs_set_stack_timespec_sec(&inode_item.mtime, now);
        btrfs_set_stack_timespec_nsec(&inode_item.mtime, 0);
        btrfs_set_stack_timespec_sec(&inode_item.otime, 0);
        btrfs_set_stack_timespec_nsec(&inode_item.otime, 0);

        if (root->fs_info->tree_root == root)
                btrfs_set_super_root_dir(root->fs_info->super_copy, objectid);

        ret = btrfs_insert_inode(trans, root, objectid, &inode_item);
        if (ret)
                goto error;

        ret = btrfs_insert_inode_ref(trans, root, "..", 2, objectid, objectid, 0);
        if (ret)
                goto error;

        btrfs_set_root_dirid(&root->root_item, objectid);
        ret = 0;
error:
        return ret;
}

/*
 * checks if a path is a block device node
 * Returns negative errno on failure, otherwise
 * returns 1 for blockdev, 0 for not-blockdev
 */
int is_block_device(const char *path)
{
        struct stat statbuf;

        if (stat(path, &statbuf) < 0)
                return -errno;

        return S_ISBLK(statbuf.st_mode);
}

/*
 * check if given path is a mount point
 * return 1 if yes. 0 if no. -1 for error
 */
int is_mount_point(const char *path)
{
        FILE *f;
        struct mntent *mnt;
        int ret = 0;

        f = setmntent("/proc/self/mounts", "r");
        if (f == NULL)
                return -1;

        while ((mnt = getmntent(f)) != NULL) {
                if (strcmp(mnt->mnt_dir, path))
                        continue;
                ret = 1;
                break;
        }
        endmntent(f);
        return ret;
}

/*
 * Find the mount point for a mounted device.
 * On success, returns 0 with mountpoint in *mp.
 * On failure, returns -errno (not mounted yields -EINVAL)
 * Is noisy on failures, expects to be given a mounted device.
 */
int get_btrfs_mount(const char *dev, char *mp, size_t mp_size)
{
        int ret;
        int fd = -1;

        ret = is_block_device(dev);
        if (ret <= 0) {
                if (!ret) {
                        fprintf(stderr, "%s is not a block device\n", dev);
                        ret = -EINVAL;
                } else {
                        fprintf(stderr, "Could not check %s: %s\n",
                                dev, strerror(-ret));
                }
                goto out;
        }

        fd = open(dev, O_RDONLY);
        if (fd < 0) {
                ret = -errno;
                fprintf(stderr, "Could not open %s: %s\n", dev, strerror(errno));
                goto out;
        }

        ret = check_mounted_where(fd, dev, mp, mp_size, NULL);
        if (!ret) {
                ret = -EINVAL;
        } else { /* mounted, all good */
                ret = 0;
        }
out:
        if (fd != -1)
                close(fd);
        return ret;
}

/*
 * Given a pathname, return a filehandle to:
 *      the original pathname or,
 *      if the pathname is a mounted btrfs device, to its mountpoint.
 *
 * On error, return -1, errno should be set.
 */
int open_path_or_dev_mnt(const char *path, DIR **dirstream)
{
        char mp[BTRFS_PATH_NAME_MAX + 1];
        int fdmnt;

        if (is_block_device(path)) {
                int ret;

                ret = get_btrfs_mount(path, mp, sizeof(mp));
                if (ret < 0) {
                        /* not a mounted btrfs dev */
                        errno = EINVAL;
                        return -1;
                }
                fdmnt = open_file_or_dir(mp, dirstream);
        } else {
                fdmnt = open_file_or_dir(path, dirstream);
        }

        return fdmnt;
}

/* checks if a device is a loop device */
static int is_loop_device (const char* device) {
        struct stat statbuf;

        if(stat(device, &statbuf) < 0)
                return -errno;

        return (S_ISBLK(statbuf.st_mode) &&
                MAJOR(statbuf.st_rdev) == LOOP_MAJOR);
}


/* Takes a loop device path (e.g. /dev/loop0) and returns
 * the associated file (e.g. /images/my_btrfs.img) */
static int resolve_loop_device(const char* loop_dev, char* loop_file,
                int max_len)
{
        int ret;
        FILE *f;
        char fmt[20];
        char p[PATH_MAX];
        char real_loop_dev[PATH_MAX];

        if (!realpath(loop_dev, real_loop_dev))
                return -errno;
        snprintf(p, PATH_MAX, "/sys/block/%s/loop/backing_file", strrchr(real_loop_dev, '/'));
        if (!(f = fopen(p, "r")))
                return -errno;

        snprintf(fmt, 20, "%%%i[^\n]", max_len-1);
        ret = fscanf(f, fmt, loop_file);
        fclose(f);
        if (ret == EOF)
                return -errno;

        return 0;
}

/* Checks whether a and b are identical or device
 * files associated with the same block device
 */
static int is_same_blk_file(const char* a, const char* b)
{
        struct stat st_buf_a, st_buf_b;
        char real_a[PATH_MAX];
        char real_b[PATH_MAX];

        if(!realpath(a, real_a))
                strcpy(real_a, a);

        if (!realpath(b, real_b))
                strcpy(real_b, b);

        /* Identical path? */
        if(strcmp(real_a, real_b) == 0)
                return 1;

        if(stat(a, &st_buf_a) < 0 ||
           stat(b, &st_buf_b) < 0)
        {
                if (errno == ENOENT)
                        return 0;
                return -errno;
        }

        /* Same blockdevice? */
        if(S_ISBLK(st_buf_a.st_mode) &&
           S_ISBLK(st_buf_b.st_mode) &&
           st_buf_a.st_rdev == st_buf_b.st_rdev)
        {
                return 1;
        }

        /* Hardlink? */
        if (st_buf_a.st_dev == st_buf_b.st_dev &&
            st_buf_a.st_ino == st_buf_b.st_ino)
        {
                return 1;
        }

        return 0;
}

/* checks if a and b are identical or device
 * files associated with the same block device or
 * if one file is a loop device that uses the other
 * file.
 */
static int is_same_loop_file(const char* a, const char* b)
{
        char res_a[PATH_MAX];
        char res_b[PATH_MAX];
        const char* final_a = NULL;
        const char* final_b = NULL;
        int ret;

        /* Resolve a if it is a loop device */
        if((ret = is_loop_device(a)) < 0) {
                if (ret == -ENOENT)
                        return 0;
                return ret;
        } else if (ret) {
                ret = resolve_loop_device(a, res_a, sizeof(res_a));
                if (ret < 0) {
                        if (errno != EPERM)
                                return ret;
                } else {
                        final_a = res_a;
                }
        } else {
                final_a = a;
        }

        /* Resolve b if it is a loop device */
        if ((ret = is_loop_device(b)) < 0) {
                if (ret == -ENOENT)
                        return 0;
                return ret;
        } else if (ret) {
                ret = resolve_loop_device(b, res_b, sizeof(res_b));
                if (ret < 0) {
                        if (errno != EPERM)
                                return ret;
                } else {
                        final_b = res_b;
                }
        } else {
                final_b = b;
        }

        return is_same_blk_file(final_a, final_b);
}

/* Checks if a file exists and is a block or regular file*/
static int is_existing_blk_or_reg_file(const char* filename)
{
        struct stat st_buf;

        if(stat(filename, &st_buf) < 0) {
                if(errno == ENOENT)
                        return 0;
                else
                        return -errno;
        }

        return (S_ISBLK(st_buf.st_mode) || S_ISREG(st_buf.st_mode));
}

/* Checks if a file is used (directly or indirectly via a loop device)
 * by a device in fs_devices
 */
static int blk_file_in_dev_list(struct btrfs_fs_devices* fs_devices,
                const char* file)
{
        int ret;
        struct list_head *head;
        struct list_head *cur;
        struct btrfs_device *device;

        head = &fs_devices->devices;
        list_for_each(cur, head) {
                device = list_entry(cur, struct btrfs_device, dev_list);

                if((ret = is_same_loop_file(device->name, file)))
                        return ret;
        }

        return 0;
}

/*
 * returns 1 if the device was mounted, < 0 on error or 0 if everything
 * is safe to continue.
 */
int check_mounted(const char* file)
{
        int fd;
        int ret;

        fd = open(file, O_RDONLY);
        if (fd < 0) {
                fprintf (stderr, "check_mounted(): Could not open %s\n", file);
                return -errno;
        }

        ret =  check_mounted_where(fd, file, NULL, 0, NULL);
        close(fd);

        return ret;
}

int check_mounted_where(int fd, const char *file, char *where, int size,
                        struct btrfs_fs_devices **fs_dev_ret)
{
        int ret;
        u64 total_devs = 1;
        int is_btrfs;
        struct btrfs_fs_devices *fs_devices_mnt = NULL;
        FILE *f;
        struct mntent *mnt;

        /* scan the initial device */
        ret = btrfs_scan_one_device(fd, file, &fs_devices_mnt,
                                    &total_devs, BTRFS_SUPER_INFO_OFFSET);
        is_btrfs = (ret >= 0);

        /* scan other devices */
        if (is_btrfs && total_devs > 1) {
                if ((ret = btrfs_scan_for_fsid(!BTRFS_UPDATE_KERNEL)))
                        return ret;
        }

        /* iterate over the list of currently mountes filesystems */
        if ((f = setmntent ("/proc/self/mounts", "r")) == NULL)
                return -errno;

        while ((mnt = getmntent (f)) != NULL) {
                if(is_btrfs) {
                        if(strcmp(mnt->mnt_type, "btrfs") != 0)
                                continue;

                        ret = blk_file_in_dev_list(fs_devices_mnt, mnt->mnt_fsname);
                } else {
                        /* ignore entries in the mount table that are not
                           associated with a file*/
                        if((ret = is_existing_blk_or_reg_file(mnt->mnt_fsname)) < 0)
                                goto out_mntloop_err;
                        else if(!ret)
                                continue;

                        ret = is_same_loop_file(file, mnt->mnt_fsname);
                }

                if(ret < 0)
                        goto out_mntloop_err;
                else if(ret)
                        break;
        }

        /* Did we find an entry in mnt table? */
        if (mnt && size && where) {
                strncpy(where, mnt->mnt_dir, size);
                where[size-1] = 0;
        }
        if (fs_dev_ret)
                *fs_dev_ret = fs_devices_mnt;

        ret = (mnt != NULL);

out_mntloop_err:
        endmntent (f);

        return ret;
}

struct pending_dir {
        struct list_head list;
        char name[PATH_MAX];
};

void btrfs_register_one_device(char *fname)
{
        struct btrfs_ioctl_vol_args args;
        int fd;
        int ret;
        int e;

        fd = open("/dev/btrfs-control", O_RDONLY);
        if (fd < 0) {
                fprintf(stderr, "failed to open /dev/btrfs-control "
                        "skipping device registration: %s\n",
                        strerror(errno));
                return;
        }
        strncpy(args.name, fname, BTRFS_PATH_NAME_MAX);
        args.name[BTRFS_PATH_NAME_MAX-1] = 0;
        ret = ioctl(fd, BTRFS_IOC_SCAN_DEV, &args);
        e = errno;
        if(ret<0){
                fprintf(stderr, "ERROR: device scan failed '%s' - %s\n",
                        fname, strerror(e));
        }
        close(fd);
}

int btrfs_scan_one_dir(char *dirname, int run_ioctl)
{
        DIR *dirp = NULL;
        struct dirent *dirent;
        struct pending_dir *pending;
        struct stat st;
        int ret;
        int fd;
        int dirname_len;
        char *fullpath;
        struct list_head pending_list;
        struct btrfs_fs_devices *tmp_devices;
        u64 num_devices;

        INIT_LIST_HEAD(&pending_list);

        pending = malloc(sizeof(*pending));
        if (!pending)
                return -ENOMEM;
        strcpy(pending->name, dirname);

again:
        dirname_len = strlen(pending->name);
        fullpath = malloc(PATH_MAX);
        dirname = pending->name;

        if (!fullpath) {
                ret = -ENOMEM;
                goto fail;
        }
        dirp = opendir(dirname);
        if (!dirp) {
                fprintf(stderr, "Unable to open %s for scanning\n", dirname);
                ret = -errno;
                goto fail;
        }
        while(1) {
                dirent = readdir(dirp);
                if (!dirent)
                        break;
                if (dirent->d_name[0] == '.')
                        continue;
                if (dirname_len + strlen(dirent->d_name) + 2 > PATH_MAX) {
                        ret = -EFAULT;
                        goto fail;
                }
                snprintf(fullpath, PATH_MAX, "%s/%s", dirname, dirent->d_name);
                ret = lstat(fullpath, &st);
                if (ret < 0) {
                        fprintf(stderr, "failed to stat %s\n", fullpath);
                        continue;
                }
                if (S_ISLNK(st.st_mode))
                        continue;
                if (S_ISDIR(st.st_mode)) {
                        struct pending_dir *next = malloc(sizeof(*next));
                        if (!next) {
                                ret = -ENOMEM;
                                goto fail;
                        }
                        strcpy(next->name, fullpath);
                        list_add_tail(&next->list, &pending_list);
                }
                if (!S_ISBLK(st.st_mode)) {
                        continue;
                }
                fd = open(fullpath, O_RDONLY);
                if (fd < 0) {
                        /* ignore the following errors:
                                ENXIO (device don't exists) 
                                ENOMEDIUM (No medium found -> 
                                        like a cd tray empty)
                        */
                        if(errno != ENXIO && errno != ENOMEDIUM) 
                                fprintf(stderr, "failed to read %s: %s\n", 
                                        fullpath, strerror(errno));
                        continue;
                }
                ret = btrfs_scan_one_device(fd, fullpath, &tmp_devices,
                                            &num_devices,
                                            BTRFS_SUPER_INFO_OFFSET);
                if (ret == 0 && run_ioctl > 0) {
                        btrfs_register_one_device(fullpath);
                }
                close(fd);
        }
        if (!list_empty(&pending_list)) {
                free(pending);
                pending = list_entry(pending_list.next, struct pending_dir,
                                     list);
                free(fullpath);
                list_del(&pending->list);
                closedir(dirp);
                dirp = NULL;
                goto again;
        }
        ret = 0;
fail:
        free(pending);
        free(fullpath);
        while (!list_empty(&pending_list)) {
                pending = list_entry(pending_list.next, struct pending_dir,
                                     list);
                list_del(&pending->list);
                free(pending);
        }
        if (dirp)
                closedir(dirp);
        return ret;
}

int btrfs_scan_for_fsid(int run_ioctls)
{
        int ret;

        ret = scan_for_btrfs(BTRFS_SCAN_PROC, run_ioctls);
        if (ret)
                ret = scan_for_btrfs(BTRFS_SCAN_DEV, run_ioctls);
        return ret;
}

int btrfs_device_already_in_root(struct btrfs_root *root, int fd,
                                 int super_offset)
{
        struct btrfs_super_block *disk_super;
        char *buf;
        int ret = 0;

        buf = malloc(BTRFS_SUPER_INFO_SIZE);
        if (!buf) {
                ret = -ENOMEM;
                goto out;
        }
        ret = pread(fd, buf, BTRFS_SUPER_INFO_SIZE, super_offset);
        if (ret != BTRFS_SUPER_INFO_SIZE)
                goto brelse;

        ret = 0;
        disk_super = (struct btrfs_super_block *)buf;
        if (btrfs_super_magic(disk_super) != BTRFS_MAGIC)
                goto brelse;

        if (!memcmp(disk_super->fsid, root->fs_info->super_copy->fsid,
                    BTRFS_FSID_SIZE))
                ret = 1;
brelse:
        free(buf);
out:
        return ret;
}

static char *size_strs[] = { "", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB"};
int pretty_size_snprintf(u64 size, char *str, size_t str_bytes)
{
        int num_divs = 0;
        float fraction;

        if (str_bytes == 0)
                return 0;

        if( size < 1024 ){
                fraction = size;
                num_divs = 0;
        } else {
                u64 last_size = size;
                num_divs = 0;
                while(size >= 1024){
                        last_size = size;
                        size /= 1024;
                        num_divs ++;
                }

                if (num_divs >= ARRAY_SIZE(size_strs)) {
                        str[0] = '\0';
                        return -1;
                }
                fraction = (float)last_size / 1024;
        }
        return snprintf(str, str_bytes, "%.2f%s", fraction,
                        size_strs[num_divs]);
}

/*
 * __strncpy__null - strncpy with null termination
 * @dest:       the target array
 * @src:        the source string
 * @n:          maximum bytes to copy (size of *dest)
 *
 * Like strncpy, but ensures destination is null-terminated.
 *
 * Copies the string pointed to by src, including the terminating null
 * byte ('\0'), to the buffer pointed to by dest, up to a maximum
 * of n bytes.  Then ensure that dest is null-terminated.
 */
char *__strncpy__null(char *dest, const char *src, size_t n)
{
        strncpy(dest, src, n);
        if (n > 0)
                dest[n - 1] = '\0';
        return dest;
}

/*
 * Checks to make sure that the label matches our requirements.
 * Returns:
       0    if everything is safe and usable
      -1    if the label is too long
 */
static int check_label(const char *input)
{
       int len = strlen(input);

       if (len > BTRFS_LABEL_SIZE - 1) {
                fprintf(stderr, "ERROR: Label %s is too long (max %d)\n",
                        input, BTRFS_LABEL_SIZE - 1);
               return -1;
       }

       return 0;
}

static int set_label_unmounted(const char *dev, const char *label)
{
        struct btrfs_trans_handle *trans;
        struct btrfs_root *root;
        int ret;

        ret = check_mounted(dev);
        if (ret < 0) {
               fprintf(stderr, "FATAL: error checking %s mount status\n", dev);
               return -1;
        }
        if (ret > 0) {
                fprintf(stderr, "ERROR: dev %s is mounted, use mount point\n",
                        dev);
                return -1;
        }

        /* Open the super_block at the default location
         * and as read-write.
         */
        root = open_ctree(dev, 0, OPEN_CTREE_WRITES);
        if (!root) /* errors are printed by open_ctree() */
                return -1;

        trans = btrfs_start_transaction(root, 1);
        snprintf(root->fs_info->super_copy->label, BTRFS_LABEL_SIZE, "%s",
                 label);
        btrfs_commit_transaction(trans, root);

        /* Now we close it since we are done. */
        close_ctree(root);
        return 0;
}

static int set_label_mounted(const char *mount_path, const char *label)
{
        int fd;

        fd = open(mount_path, O_RDONLY | O_NOATIME);
        if (fd < 0) {
                fprintf(stderr, "ERROR: unable to access '%s'\n", mount_path);
                return -1;
        }

        if (ioctl(fd, BTRFS_IOC_SET_FSLABEL, label) < 0) {
                fprintf(stderr, "ERROR: unable to set label %s\n",
                        strerror(errno));
                close(fd);
                return -1;
        }

        close(fd);
        return 0;
}

static int get_label_unmounted(const char *dev, char *label)
{
        struct btrfs_root *root;
        int ret;

        ret = check_mounted(dev);
        if (ret < 0) {
               fprintf(stderr, "FATAL: error checking %s mount status\n", dev);
               return -1;
        }
        if (ret > 0) {
                fprintf(stderr, "ERROR: dev %s is mounted, use mount point\n",
                        dev);
                return -1;
        }

        /* Open the super_block at the default location
         * and as read-only.
         */
        root = open_ctree(dev, 0, 0);
        if(!root)
                return -1;

        memcpy(label, root->fs_info->super_copy->label, BTRFS_LABEL_SIZE);

        /* Now we close it since we are done. */
        close_ctree(root);
        return 0;
}

/*
 * If a partition is mounted, try to get the filesystem label via its
 * mounted path rather than device.  Return the corresponding error
 * the user specified the device path.
 */
int get_label_mounted(const char *mount_path, char *labelp)
{
        char label[BTRFS_LABEL_SIZE];
        int fd;

        fd = open(mount_path, O_RDONLY | O_NOATIME);
        if (fd < 0) {
                fprintf(stderr, "ERROR: unable to access '%s'\n", mount_path);
                return -1;
        }

        memset(label, '\0', sizeof(label));
        if (ioctl(fd, BTRFS_IOC_GET_FSLABEL, label) < 0) {
                fprintf(stderr, "ERROR: unable get label %s\n", strerror(errno));
                close(fd);
                return -1;
        }

        strncpy(labelp, label, sizeof(label));
        close(fd);
        return 0;
}

int get_label(const char *btrfs_dev, char *label)
{
        int ret;

        if (is_existing_blk_or_reg_file(btrfs_dev))
                ret = get_label_unmounted(btrfs_dev, label);
        else
                ret = get_label_mounted(btrfs_dev, label);

        return ret;
}

int set_label(const char *btrfs_dev, const char *label)
{
        if (check_label(label))
                return -1;

        return is_existing_blk_or_reg_file(btrfs_dev) ?
                set_label_unmounted(btrfs_dev, label) :
                set_label_mounted(btrfs_dev, label);
}

int btrfs_scan_block_devices(int run_ioctl)
{

        struct stat st;
        int ret;
        int fd;
        struct btrfs_fs_devices *tmp_devices;
        u64 num_devices;
        FILE *proc_partitions;
        int i;
        char buf[1024];
        char fullpath[110];
        int scans = 0;
        int special;

scan_again:
        proc_partitions = fopen("/proc/partitions","r");
        if (!proc_partitions) {
                fprintf(stderr, "Unable to open '/proc/partitions' for scanning\n");
                return -ENOENT;
        }
        /* skip the header */
        for (i = 0; i < 2; i++)
                if (!fgets(buf, 1023, proc_partitions)) {
                        fprintf(stderr,
                                "Unable to read '/proc/partitions' for scanning\n");
                        fclose(proc_partitions);
                        return -ENOENT;
                }

        strcpy(fullpath,"/dev/");
        while(fgets(buf, 1023, proc_partitions)) {
                i = sscanf(buf," %*d %*d %*d %99s", fullpath+5);

                /*
                 * multipath and MD devices may register as a btrfs filesystem
                 * both through the original block device and through
                 * the special (/dev/mapper or /dev/mdX) entry.
                 * This scans the special entries last
                 */
                special = strncmp(fullpath, "/dev/dm-", strlen("/dev/dm-")) == 0;
                if (!special)
                        special = strncmp(fullpath, "/dev/md", strlen("/dev/md")) == 0;

                if (scans == 0 && special)
                        continue;
                if (scans > 0 && !special)
                        continue;

                ret = lstat(fullpath, &st);
                if (ret < 0) {
                        fprintf(stderr, "failed to stat %s\n", fullpath);
                        continue;
                }
                if (!S_ISBLK(st.st_mode)) {
                        continue;
                }

                fd = open(fullpath, O_RDONLY);
                if (fd < 0) {
                        if (errno != ENOMEDIUM)
                                fprintf(stderr, "failed to open %s: %s\n",
                                        fullpath, strerror(errno));
                        continue;
                }
                ret = btrfs_scan_one_device(fd, fullpath, &tmp_devices,
                                            &num_devices,
                                            BTRFS_SUPER_INFO_OFFSET);
                if (ret == 0 && run_ioctl > 0) {
                        btrfs_register_one_device(fullpath);
                }
                close(fd);
        }

        fclose(proc_partitions);

        if (scans == 0) {
                scans++;
                goto scan_again;
        }
        return 0;
}

/*
 * This function should be only used when parsing
 * command arg, it won't return error to it's
 * caller and rather exit directly just like usage().
 */
u64 arg_strtou64(const char *str)
{
        u64 value;
        char *ptr_parse_end = NULL;

        value = strtoull(str, &ptr_parse_end, 0);
        if (ptr_parse_end && *ptr_parse_end != '\0') {
                fprintf(stderr, "ERROR: %s is not a valid numeric value.\n",
                        str);
                exit(1);
        }
        /*
         * if we pass a negative number to strtoull,
         * it will return an unexpected number to us,
         * so let's do the check ourselves.
         */
        if (str[0] == '-') {
                fprintf(stderr, "ERROR: %s: negative value is invalid.\n",
                        str);
                exit(1);
        }
        if (value == ULLONG_MAX) {
                fprintf(stderr, "ERROR: %s is too large.\n", str);
                exit(1);
        }
        return value;
}

u64 parse_size(char *s)
{
        int i;
        char c;
        u64 mult = 1;

        for (i = 0; s && s[i] && isdigit(s[i]); i++) ;
        if (!i) {
                fprintf(stderr, "ERROR: size value is empty\n");
                exit(50);
        }

        if (s[i]) {
                c = tolower(s[i]);
                switch (c) {
                case 'e':
                        mult *= 1024;
                        /* fallthrough */
                case 'p':
                        mult *= 1024;
                        /* fallthrough */
                case 't':
                        mult *= 1024;
                        /* fallthrough */
                case 'g':
                        mult *= 1024;
                        /* fallthrough */
                case 'm':
                        mult *= 1024;
                        /* fallthrough */
                case 'k':
                        mult *= 1024;
                        /* fallthrough */
                case 'b':
                        break;
                default:
                        fprintf(stderr, "ERROR: Unknown size descriptor "
                                "'%c'\n", c);
                        exit(1);
                }
        }
        if (s[i] && s[i+1]) {
                fprintf(stderr, "ERROR: Illegal suffix contains "
                        "character '%c' in wrong position\n",
                        s[i+1]);
                exit(51);
        }
        return strtoull(s, NULL, 10) * mult;
}

int open_file_or_dir(const char *fname, DIR **dirstream)
{
        int ret;
        struct stat st;
        int fd;

        ret = stat(fname, &st);
        if (ret < 0) {
                return -1;
        }
        if (S_ISDIR(st.st_mode)) {
                *dirstream = opendir(fname);
                if (!*dirstream)
                        return -1;
                fd = dirfd(*dirstream);
        } else if (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode)) {
                fd = open(fname, O_RDWR);
        } else {
                /*
                 * we set this on purpose, in case the caller output
                 * strerror(errno) as success
                 */
                errno = EINVAL;
                return -1;
        }
        if (fd < 0) {
                fd = -1;
                if (*dirstream)
                        closedir(*dirstream);
        }
        return fd;
}

void close_file_or_dir(int fd, DIR *dirstream)
{
        if (dirstream)
                closedir(dirstream);
        else if (fd >= 0)
                close(fd);
}

int get_device_info(int fd, u64 devid,
                struct btrfs_ioctl_dev_info_args *di_args)
{
        int ret;

        di_args->devid = devid;
        memset(&di_args->uuid, '\0', sizeof(di_args->uuid));

        ret = ioctl(fd, BTRFS_IOC_DEV_INFO, di_args);
        return ret ? -errno : 0;
}

/*
 * For a given path, fill in the ioctl fs_ and info_ args.
 * If the path is a btrfs mountpoint, fill info for all devices.
 * If the path is a btrfs device, fill in only that device.
 *
 * The path provided must be either on a mounted btrfs fs,
 * or be a mounted btrfs device.
 *
 * Returns 0 on success, or a negative errno.
 */
int get_fs_info(char *path, struct btrfs_ioctl_fs_info_args *fi_args,
                struct btrfs_ioctl_dev_info_args **di_ret)
{
        int fd = -1;
        int ret = 0;
        int ndevs = 0;
        int i = 0;
        struct btrfs_fs_devices *fs_devices_mnt = NULL;
        struct btrfs_ioctl_dev_info_args *di_args;
        char mp[BTRFS_PATH_NAME_MAX + 1];
        DIR *dirstream = NULL;

        memset(fi_args, 0, sizeof(*fi_args));

        if (is_block_device(path)) {
                struct btrfs_super_block *disk_super;
                char buf[BTRFS_SUPER_INFO_SIZE];
                u64 devid;

                /* Ensure it's mounted, then set path to the mountpoint */
                fd = open(path, O_RDONLY);
                if (fd < 0) {
                        ret = -errno;
                        fprintf(stderr, "Couldn't open %s: %s\n",
                                path, strerror(errno));
                        goto out;
                }
                ret = check_mounted_where(fd, path, mp, sizeof(mp),
                                          &fs_devices_mnt);
                if (!ret) {
                        ret = -EINVAL;
                        goto out;
                }
                if (ret < 0)
                        goto out;
                path = mp;
                /* Only fill in this one device */
                fi_args->num_devices = 1;

                disk_super = (struct btrfs_super_block *)buf;
                ret = btrfs_read_dev_super(fd, disk_super, BTRFS_SUPER_INFO_OFFSET);
                if (ret < 0) {
                        ret = -EIO;
                        goto out;
                }
                devid = btrfs_stack_device_id(&disk_super->dev_item);

                fi_args->max_id = devid;
                i = devid;

                memcpy(fi_args->fsid, fs_devices_mnt->fsid, BTRFS_FSID_SIZE);
                close(fd);
        }

        /* at this point path must not be for a block device */
        fd = open_file_or_dir(path, &dirstream);
        if (fd < 0) {
                ret = -errno;
                goto out;
        }

        /* fill in fi_args if not just a single device */
        if (fi_args->num_devices != 1) {
                ret = ioctl(fd, BTRFS_IOC_FS_INFO, fi_args);
                if (ret < 0) {
                        ret = -errno;
                        goto out;
                }
        }

        if (!fi_args->num_devices)
                goto out;

        di_args = *di_ret = malloc(fi_args->num_devices * sizeof(*di_args));
        if (!di_args) {
                ret = -errno;
                goto out;
        }

        for (; i <= fi_args->max_id; ++i) {
                BUG_ON(ndevs >= fi_args->num_devices);
                ret = get_device_info(fd, i, &di_args[ndevs]);
                if (ret == -ENODEV)
                        continue;
                if (ret)
                        goto out;
                ndevs++;
        }

        /*
        * only when the only dev we wanted to find is not there then
        * let any error be returned
        */
        if (fi_args->num_devices != 1) {
                BUG_ON(ndevs == 0);
                ret = 0;
        }

out:
        close_file_or_dir(fd, dirstream);
        return ret;
}

#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(
        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;
}

int test_num_disk_vs_raid(u64 metadata_profile, u64 data_profile,
        u64 dev_cnt, int mixed, char *estr)
{
        size_t sz = 100;
        u64 allowed = 0;

        switch (dev_cnt) {
        default:
        case 4:
                allowed |= BTRFS_BLOCK_GROUP_RAID10;
        case 3:
                allowed |= BTRFS_BLOCK_GROUP_RAID6;
        case 2:
                allowed |= BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
                        BTRFS_BLOCK_GROUP_RAID5;
                break;
        case 1:
                allowed |= BTRFS_BLOCK_GROUP_DUP;
        }

        if (metadata_profile & ~allowed) {
                snprintf(estr, sz, "unable to create FS with metadata "
                        "profile %llu (have %llu devices)\n",
                        metadata_profile, dev_cnt);
                return 1;
        }
        if (data_profile & ~allowed) {
                snprintf(estr, sz, "unable to create FS with data "
                        "profile %llu (have %llu devices)\n",
                        metadata_profile, dev_cnt);
                return 1;
        }

        if (!mixed && (data_profile & BTRFS_BLOCK_GROUP_DUP)) {
                snprintf(estr, sz,
                        "dup for data is allowed only in mixed mode");
                return 1;
        }
        return 0;
}

/* Check if disk is suitable for btrfs
 * returns:
 *  1: something is wrong, estr provides the error
 *  0: all is fine
 */
int test_dev_for_mkfs(char *file, int force_overwrite, char *estr)
{
        int ret, fd;
        size_t sz = 100;
        struct stat st;

        ret = is_swap_device(file);
        if (ret < 0) {
                snprintf(estr, sz, "error checking %s status: %s\n", file,
                        strerror(-ret));
                return 1;
        }
        if (ret == 1) {
                snprintf(estr, sz, "%s is a swap device\n", file);
                return 1;
        }
        if (!force_overwrite) {
                if (check_overwrite(file)) {
                        snprintf(estr, sz, "Use the -f option to force overwrite.\n");
                        return 1;
                }
        }
        ret = check_mounted(file);
        if (ret < 0) {
                snprintf(estr, sz, "error checking %s mount status\n",
                        file);
                return 1;
        }
        if (ret == 1) {
                snprintf(estr, sz, "%s is mounted\n", file);
                return 1;
        }
        /* check if the device is busy */
        fd = open(file, O_RDWR|O_EXCL);
        if (fd < 0) {
                snprintf(estr, sz, "unable to open %s: %s\n", file,
                        strerror(errno));
                return 1;
        }
        if (fstat(fd, &st)) {
                snprintf(estr, sz, "unable to stat %s: %s\n", file,
                        strerror(errno));
                close(fd);
                return 1;
        }
        if (!S_ISBLK(st.st_mode)) {
                fprintf(stderr, "'%s' is not a block device\n", file);
                close(fd);
                return 1;
        }
        close(fd);
        return 0;
}

int btrfs_scan_lblkid(int update_kernel)
{
        int fd = -1;
        int ret;
        u64 num_devices;
        struct btrfs_fs_devices *tmp_devices;
        blkid_dev_iterate iter = NULL;
        blkid_dev dev = NULL;
        blkid_cache cache = NULL;
        char path[PATH_MAX];

        if (blkid_get_cache(&cache, 0) < 0) {
                printf("ERROR: lblkid cache get failed\n");
                return 1;
        }
        blkid_probe_all(cache);
        iter = blkid_dev_iterate_begin(cache);
        blkid_dev_set_search(iter, "TYPE", "btrfs");
        while (blkid_dev_next(iter, &dev) == 0) {
                dev = blkid_verify(cache, dev);
                if (!dev)
                        continue;
                /* if we are here its definitely a btrfs disk*/
                strncpy(path, blkid_dev_devname(dev), PATH_MAX);

                fd = open(path, O_RDONLY);
                if (fd < 0) {
                        printf("ERROR: could not open %s\n", path);
                        continue;
                }
                ret = btrfs_scan_one_device(fd, path, &tmp_devices,
                                &num_devices, BTRFS_SUPER_INFO_OFFSET);
                if (ret) {
                        printf("ERROR: could not scan %s\n", path);
                        close (fd);
                        continue;
                }

                close(fd);
                if (update_kernel)
                        btrfs_register_one_device(path);
        }
        blkid_dev_iterate_end(iter);
        blkid_put_cache(cache);
        return 0;
}

/*
 * scans devs for the btrfs
*/
int scan_for_btrfs(int where, int update_kernel)
{
        int ret = 0;

        switch (where) {
        case BTRFS_SCAN_PROC:
                ret = btrfs_scan_block_devices(update_kernel);
                break;
        case BTRFS_SCAN_DEV:
                ret = btrfs_scan_one_dir("/dev", update_kernel);
                break;
        case BTRFS_SCAN_LBLKID:
                ret = btrfs_scan_lblkid(update_kernel);
                break;
        }
        return ret;
}

int is_vol_small(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 < 1024 * 1024 * 1024) {
                close(fd);
                return 1;
        } else {
                close(fd);
                return 0;
        }
}

/*
 * This reads a line from the stdin and only returns non-zero if the
 * first whitespace delimited token is a case insensitive match with yes
 * or y.
 */
int ask_user(char *question)
{
        char buf[30] = {0,};
        char *saveptr = NULL;
        char *answer;

        printf("%s [y/N]: ", question);

        return fgets(buf, sizeof(buf) - 1, stdin) &&
               (answer = strtok_r(buf, " \t\n\r", &saveptr)) &&
               (!strcasecmp(answer, "yes") || !strcasecmp(answer, "y"));
}

/*
 * For a given:
 * - file or directory return the containing tree root id
 * - subvolume return it's own tree id
 * - BTRFS_EMPTY_SUBVOL_DIR_OBJECTID (directory with ino == 2) the result is
 *   undefined and function returns -1
 */
int lookup_ino_rootid(int fd, u64 *rootid)
{
        struct btrfs_ioctl_ino_lookup_args args;
        int ret;
        int e;

        memset(&args, 0, sizeof(args));
        args.treeid = 0;
        args.objectid = BTRFS_FIRST_FREE_OBJECTID;

        ret = ioctl(fd, BTRFS_IOC_INO_LOOKUP, &args);
        e = errno;
        if (ret) {
                fprintf(stderr, "ERROR: Failed to lookup root id - %s\n",
                        strerror(e));
                return ret;
        }

        *rootid = args.treeid;

        return 0;
}

int find_mount_root(const char *path, char **mount_root)
{
        FILE *mnttab;
        int fd;
        struct mntent *ent;
        int len;
        int ret;
        int longest_matchlen = 0;
        char *longest_match = NULL;

        fd = open(path, O_RDONLY | O_NOATIME);
        if (fd < 0)
                return -errno;
        close(fd);

        mnttab = setmntent("/proc/self/mounts", "r");
        if (!mnttab)
                return -errno;

        while ((ent = getmntent(mnttab))) {
                len = strlen(ent->mnt_dir);
                if (strncmp(ent->mnt_dir, path, len) == 0) {
                        /* match found */
                        if (longest_matchlen < len) {
                                free(longest_match);
                                longest_matchlen = len;
                                longest_match = strdup(ent->mnt_dir);
                        }
                }
        }
        endmntent(mnttab);

        if (!longest_match) {
                fprintf(stderr,
                        "ERROR: Failed to find mount root for path %s.\n",
                        path);
                return -ENOENT;
        }

        ret = 0;
        *mount_root = realpath(longest_match, NULL);
        if (!*mount_root)
                ret = -errno;

        free(longest_match);
        return ret;
}