utils.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #define _XOPEN_SOURCE 600
  20 #define __USE_XOPEN2K
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #ifndef __CHECKER__
  24 #include <sys/ioctl.h>
  25 #include <sys/mount.h>
  26 #endif
  27 #include <sys/types.h>
  28 #include <sys/stat.h>
  29 #include <uuid/uuid.h>
  30 #include <dirent.h>
  31 #include <fcntl.h>
  32 #include <unistd.h>
  33 #include <mntent.h>
  34 #include "kerncompat.h"
  35 #include "radix-tree.h"
  36 #include "ctree.h"
  37 #include "disk-io.h"
  38 #include "transaction.h"
  39 #include "crc32c.h"
  40 #include "utils.h"
  41 #include "volumes.h"
  42 #include "ioctl.h"
  43
  44 #ifdef __CHECKER__
  45 #define BLKGETSIZE64 0
  46 static inline int ioctl(int fd, int define, u64 *size) { return 0; }
  47 #endif
  48
  49 static u64 reference_root_table[6] = {
  50         [1] =   BTRFS_ROOT_TREE_OBJECTID,
  51         [2] =   BTRFS_EXTENT_TREE_OBJECTID,
  52         [3] =   BTRFS_CHUNK_TREE_OBJECTID,
  53         [4] =   BTRFS_DEV_TREE_OBJECTID,
  54         [5] =   BTRFS_FS_TREE_OBJECTID,
  55 };
  56
  57 int make_btrfs(int fd, char *device_name,
  58                u64 blocks[6], u64 num_bytes, u32 nodesize,
  59                u32 leafsize, u32 sectorsize, u32 stripesize)
  60 {
  61         struct btrfs_super_block super;
  62         struct extent_buffer *buf;
  63         struct btrfs_root_item root_item;
  64         struct btrfs_disk_key disk_key;
  65         struct btrfs_extent_ref *extent_ref;
  66         struct btrfs_extent_item *extent_item;
  67         struct btrfs_inode_item *inode_item;
  68         struct btrfs_chunk *chunk;
  69         struct btrfs_dev_item *dev_item;
  70         struct btrfs_dev_extent *dev_extent;
  71         u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
  72         u8 *ptr;
  73         int i;
  74         int ret;
  75         u32 itemoff;
  76         u32 nritems = 0;
  77         u64 hash;
  78         u64 first_free;
  79         u64 ref_gen;
  80         u64 ref_root;
  81         u32 array_size;
  82         u32 item_size;
  83
  84         first_free = BTRFS_SUPER_INFO_OFFSET + sectorsize * 2 - 1;
  85         first_free &= ~((u64)sectorsize - 1);
  86
  87         num_bytes = (num_bytes / sectorsize) * sectorsize;
  88         uuid_generate(super.fsid);
  89         uuid_generate(super.dev_item.uuid);
  90
  91         uuid_generate(chunk_tree_uuid);
  92
  93         btrfs_set_super_bytenr(&super, blocks[0]);
  94         btrfs_set_super_num_devices(&super, 1);
  95         strncpy((char *)&super.magic, BTRFS_MAGIC, sizeof(super.magic));
  96         btrfs_set_super_generation(&super, 1);
  97         btrfs_set_super_root(&super, blocks[1]);
  98         btrfs_set_super_chunk_root(&super, blocks[3]);
  99         btrfs_set_super_total_bytes(&super, num_bytes);
 100         btrfs_set_super_bytes_used(&super, first_free + 5 * leafsize);
 101         btrfs_set_super_root_dir(&super, 0);
 102         btrfs_set_super_sectorsize(&super, sectorsize);
 103         btrfs_set_super_leafsize(&super, leafsize);
 104         btrfs_set_super_nodesize(&super, nodesize);
 105         btrfs_set_super_stripesize(&super, stripesize);
 106         btrfs_set_super_root_level(&super, 0);
 107         btrfs_set_super_chunk_root_level(&super, 0);
 108         btrfs_set_super_sys_array_size(&super, 0);
 109
 110         buf = malloc(sizeof(*buf) + max(sectorsize, leafsize));
 111
 112         /* create the tree of root objects */
 113         memset(buf->data, 0, leafsize);
 114         buf->len = leafsize;
 115         btrfs_set_header_bytenr(buf, blocks[1]);
 116         btrfs_set_header_nritems(buf, 3);
 117         btrfs_set_header_generation(buf, 1);
 118         btrfs_set_header_owner(buf, BTRFS_ROOT_TREE_OBJECTID);
 119         write_extent_buffer(buf, super.fsid, (unsigned long)
 120                             btrfs_header_fsid(buf), BTRFS_FSID_SIZE);
 121
 122         write_extent_buffer(buf, chunk_tree_uuid, (unsigned long)
 123                             btrfs_header_chunk_tree_uuid(buf),
 124                             BTRFS_UUID_SIZE);
 125
 126         /* create the items for the root tree */
 127         memset(&root_item, 0, sizeof(root_item));
 128         inode_item = &root_item.inode;
 129         btrfs_set_stack_inode_generation(inode_item, 1);
 130         btrfs_set_stack_inode_size(inode_item, 3);
 131         btrfs_set_stack_inode_nlink(inode_item, 1);
 132         btrfs_set_stack_inode_nblocks(inode_item, 1);
 133         btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
 134         btrfs_set_root_refs(&root_item, 1);
 135         btrfs_set_root_used(&root_item, leafsize);
 136
 137         memset(&disk_key, 0, sizeof(disk_key));
 138         btrfs_set_disk_key_type(&disk_key, BTRFS_ROOT_ITEM_KEY);
 139         btrfs_set_disk_key_offset(&disk_key, 0);
 140         nritems = 0;
 141
 142         itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize) - sizeof(root_item);
 143         btrfs_set_root_bytenr(&root_item, blocks[2]);
 144         btrfs_set_disk_key_objectid(&disk_key, BTRFS_EXTENT_TREE_OBJECTID);
 145         btrfs_set_item_key(buf, &disk_key, nritems);
 146         btrfs_set_item_offset(buf, btrfs_item_nr(buf, nritems), itemoff);
 147         btrfs_set_item_size(buf, btrfs_item_nr(buf, nritems),
 148                             sizeof(root_item));
 149         write_extent_buffer(buf, &root_item, btrfs_item_ptr_offset(buf,
 150                             nritems), sizeof(root_item));
 151         nritems++;
 152
 153         itemoff = itemoff - sizeof(root_item);
 154         btrfs_set_root_bytenr(&root_item, blocks[4]);
 155         btrfs_set_disk_key_objectid(&disk_key, BTRFS_DEV_TREE_OBJECTID);
 156         btrfs_set_item_key(buf, &disk_key, nritems);
 157         btrfs_set_item_offset(buf, btrfs_item_nr(buf, nritems), itemoff);
 158         btrfs_set_item_size(buf, btrfs_item_nr(buf, nritems),
 159                             sizeof(root_item));
 160         write_extent_buffer(buf, &root_item,
 161                             btrfs_item_ptr_offset(buf, nritems),
 162                             sizeof(root_item));
 163         nritems++;
 164
 165         itemoff = itemoff - sizeof(root_item);
 166         btrfs_set_root_bytenr(&root_item, blocks[5]);
 167         btrfs_set_disk_key_objectid(&disk_key, BTRFS_FS_TREE_OBJECTID);
 168         btrfs_set_item_key(buf, &disk_key, nritems);
 169         btrfs_set_item_offset(buf, btrfs_item_nr(buf, nritems), itemoff);
 170         btrfs_set_item_size(buf, btrfs_item_nr(buf, nritems),
 171                             sizeof(root_item));
 172         write_extent_buffer(buf, &root_item,
 173                             btrfs_item_ptr_offset(buf, nritems),
 174                             sizeof(root_item));
 175         nritems++;
 176
 177
 178         csum_tree_block(NULL, buf, 0);
 179         ret = pwrite(fd, buf->data, leafsize, blocks[1]);
 180         BUG_ON(ret != leafsize);
 181
 182         /* create the items for the extent tree */
 183         nritems = 0;
 184         itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize) -
 185                   sizeof(struct btrfs_extent_item);
 186         btrfs_set_disk_key_objectid(&disk_key, 0);
 187         btrfs_set_disk_key_offset(&disk_key, first_free);
 188         btrfs_set_disk_key_type(&disk_key, BTRFS_EXTENT_ITEM_KEY);
 189         btrfs_set_item_key(buf, &disk_key, nritems);
 190         btrfs_set_item_offset(buf, btrfs_item_nr(buf, nritems), itemoff);
 191         btrfs_set_item_size(buf, btrfs_item_nr(buf,  nritems),
 192                             sizeof(struct btrfs_extent_item));
 193         extent_item = btrfs_item_ptr(buf, nritems, struct btrfs_extent_item);
 194         btrfs_set_extent_refs(buf, extent_item, 1);
 195         nritems++;
 196         for (i = 1; i < 6; i++) {
 197                 BUG_ON(blocks[i] < first_free);
 198                 BUG_ON(blocks[i] < blocks[i - 1]);
 199
 200                 /* create extent item */
 201                 itemoff = itemoff - sizeof(struct btrfs_extent_item);
 202                 btrfs_set_disk_key_objectid(&disk_key, blocks[i]);
 203                 btrfs_set_disk_key_offset(&disk_key, leafsize);
 204                 btrfs_set_disk_key_type(&disk_key, BTRFS_EXTENT_ITEM_KEY);
 205                 btrfs_set_item_key(buf, &disk_key, nritems);
 206                 btrfs_set_item_offset(buf, btrfs_item_nr(buf, nritems),
 207                                       itemoff);
 208                 btrfs_set_item_size(buf, btrfs_item_nr(buf, nritems),
 209                                     sizeof(struct btrfs_extent_item));
 210                 extent_item = btrfs_item_ptr(buf, nritems,
 211                                              struct btrfs_extent_item);
 212                 btrfs_set_extent_refs(buf, extent_item, 1);
 213                 nritems++;
 214
 215                 /* create extent ref */
 216                 ref_root = reference_root_table[i];
 217                 if (ref_root == BTRFS_FS_TREE_OBJECTID)
 218                         ref_gen = 1;
 219                 else
 220                         ref_gen = 0;
 221
 222                 hash = btrfs_hash_extent_ref(ref_root, ref_gen, 0, 0);
 223                 itemoff = itemoff - sizeof(struct btrfs_extent_ref);
 224                 btrfs_set_disk_key_objectid(&disk_key, blocks[i]);
 225                 btrfs_set_disk_key_offset(&disk_key, hash);
 226                 btrfs_set_disk_key_type(&disk_key, BTRFS_EXTENT_REF_KEY);
 227                 btrfs_set_item_key(buf, &disk_key, nritems);
 228                 btrfs_set_item_offset(buf, btrfs_item_nr(buf, nritems),
 229                                       itemoff);
 230                 btrfs_set_item_size(buf, btrfs_item_nr(buf, nritems),
 231                                     sizeof(struct btrfs_extent_ref));
 232                 extent_ref = btrfs_item_ptr(buf, nritems,
 233                                              struct btrfs_extent_ref);
 234                 btrfs_set_ref_root(buf, extent_ref, ref_root);
 235                 btrfs_set_ref_generation(buf, extent_ref, ref_gen);
 236                 btrfs_set_ref_objectid(buf, extent_ref, 0);
 237                 btrfs_set_ref_offset(buf, extent_ref, 0);
 238                 nritems++;
 239         }
 240         btrfs_set_header_bytenr(buf, blocks[2]);
 241         btrfs_set_header_owner(buf, BTRFS_EXTENT_TREE_OBJECTID);
 242         btrfs_set_header_nritems(buf, nritems);
 243         csum_tree_block(NULL, buf, 0);
 244         ret = pwrite(fd, buf->data, leafsize, blocks[2]);
 245         BUG_ON(ret != leafsize);
 246
 247         /* create the chunk tree */
 248         nritems = 0;
 249         item_size = sizeof(*dev_item);
 250         itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize) - item_size;
 251
 252         /* first device 1 (there is no device 0) */
 253         btrfs_set_disk_key_objectid(&disk_key, BTRFS_DEV_ITEMS_OBJECTID);
 254         btrfs_set_disk_key_offset(&disk_key, 1);
 255         btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_ITEM_KEY);
 256         btrfs_set_item_key(buf, &disk_key, nritems);
 257         btrfs_set_item_offset(buf, btrfs_item_nr(buf, nritems), itemoff);
 258         btrfs_set_item_size(buf, btrfs_item_nr(buf, nritems), item_size);
 259
 260         dev_item = btrfs_item_ptr(buf, nritems, struct btrfs_dev_item);
 261         btrfs_set_device_id(buf, dev_item, 1);
 262         btrfs_set_device_total_bytes(buf, dev_item, num_bytes);
 263         btrfs_set_device_bytes_used(buf, dev_item,
 264                                     BTRFS_MKFS_SYSTEM_GROUP_SIZE);
 265         btrfs_set_device_io_align(buf, dev_item, sectorsize);
 266         btrfs_set_device_io_width(buf, dev_item, sectorsize);
 267         btrfs_set_device_sector_size(buf, dev_item, sectorsize);
 268         btrfs_set_device_type(buf, dev_item, 0);
 269
 270         write_extent_buffer(buf, super.dev_item.uuid,
 271                             (unsigned long)btrfs_device_uuid(dev_item),
 272                             BTRFS_UUID_SIZE);
 273         read_extent_buffer(buf, &super.dev_item, (unsigned long)dev_item,
 274                            sizeof(*dev_item));
 275
 276         nritems++;
 277         item_size = btrfs_chunk_item_size(1);
 278         itemoff = itemoff - item_size;
 279
 280         /* then we have chunk 0 */
 281         btrfs_set_disk_key_objectid(&disk_key, BTRFS_FIRST_CHUNK_TREE_OBJECTID);
 282         btrfs_set_disk_key_offset(&disk_key, 0);
 283         btrfs_set_disk_key_type(&disk_key, BTRFS_CHUNK_ITEM_KEY);
 284         btrfs_set_item_key(buf, &disk_key, nritems);
 285         btrfs_set_item_offset(buf, btrfs_item_nr(buf, nritems), itemoff);
 286         btrfs_set_item_size(buf, btrfs_item_nr(buf,  nritems), item_size);
 287
 288         chunk = btrfs_item_ptr(buf, nritems, struct btrfs_chunk);
 289         btrfs_set_chunk_length(buf, chunk, BTRFS_MKFS_SYSTEM_GROUP_SIZE);
 290         btrfs_set_chunk_owner(buf, chunk, BTRFS_EXTENT_TREE_OBJECTID);
 291         btrfs_set_chunk_stripe_len(buf, chunk, 64 * 1024);
 292         btrfs_set_chunk_type(buf, chunk, BTRFS_BLOCK_GROUP_SYSTEM);
 293         btrfs_set_chunk_io_align(buf, chunk, sectorsize);
 294         btrfs_set_chunk_io_width(buf, chunk, sectorsize);
 295         btrfs_set_chunk_sector_size(buf, chunk, sectorsize);
 296         btrfs_set_chunk_num_stripes(buf, chunk, 1);
 297         btrfs_set_stripe_devid_nr(buf, chunk, 0, 1);
 298         btrfs_set_stripe_offset_nr(buf, chunk, 0, 0);
 299         nritems++;
 300
 301         write_extent_buffer(buf, super.dev_item.uuid,
 302                             (unsigned long)btrfs_stripe_dev_uuid(&chunk->stripe),
 303                             BTRFS_UUID_SIZE);
 304
 305         /* copy the key for the chunk to the system array */
 306         ptr = super.sys_chunk_array;
 307         array_size = sizeof(disk_key);
 308
 309         memcpy(ptr, &disk_key, sizeof(disk_key));
 310         ptr += sizeof(disk_key);
 311
 312         /* copy the chunk to the system array */
 313         read_extent_buffer(buf, ptr, (unsigned long)chunk, item_size);
 314         array_size += item_size;
 315         ptr += item_size;
 316         btrfs_set_super_sys_array_size(&super, array_size);
 317
 318         btrfs_set_header_bytenr(buf, blocks[3]);
 319         btrfs_set_header_owner(buf, BTRFS_CHUNK_TREE_OBJECTID);
 320         btrfs_set_header_nritems(buf, nritems);
 321         csum_tree_block(NULL, buf, 0);
 322         ret = pwrite(fd, buf->data, leafsize, blocks[3]);
 323
 324         /* create the device tree */
 325         nritems = 0;
 326         itemoff = __BTRFS_LEAF_DATA_SIZE(leafsize) -
 327                 sizeof(struct btrfs_dev_extent);
 328
 329         btrfs_set_disk_key_objectid(&disk_key, 1);
 330         btrfs_set_disk_key_offset(&disk_key, 0);
 331         btrfs_set_disk_key_type(&disk_key, BTRFS_DEV_EXTENT_KEY);
 332         btrfs_set_item_key(buf, &disk_key, nritems);
 333         btrfs_set_item_offset(buf, btrfs_item_nr(buf, nritems), itemoff);
 334         btrfs_set_item_size(buf, btrfs_item_nr(buf,  nritems),
 335                             sizeof(struct btrfs_dev_extent));
 336         dev_extent = btrfs_item_ptr(buf, nritems, struct btrfs_dev_extent);
 337         btrfs_set_dev_extent_chunk_tree(buf, dev_extent,
 338                                         BTRFS_CHUNK_TREE_OBJECTID);
 339         btrfs_set_dev_extent_chunk_objectid(buf, dev_extent,
 340                                         BTRFS_FIRST_CHUNK_TREE_OBJECTID);
 341         btrfs_set_dev_extent_chunk_offset(buf, dev_extent, 0);
 342
 343         write_extent_buffer(buf, chunk_tree_uuid,
 344                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(dev_extent),
 345                     BTRFS_UUID_SIZE);
 346
 347         btrfs_set_dev_extent_length(buf, dev_extent,
 348                                     BTRFS_MKFS_SYSTEM_GROUP_SIZE);
 349         nritems++;
 350
 351         btrfs_set_header_bytenr(buf, blocks[4]);
 352         btrfs_set_header_owner(buf, BTRFS_DEV_TREE_OBJECTID);
 353         btrfs_set_header_nritems(buf, nritems);
 354         csum_tree_block(NULL, buf, 0);
 355         ret = pwrite(fd, buf->data, leafsize, blocks[4]);
 356
 357         /* finally create the FS root */
 358         btrfs_set_header_bytenr(buf, blocks[5]);
 359         btrfs_set_header_owner(buf, BTRFS_FS_TREE_OBJECTID);
 360         btrfs_set_header_nritems(buf, 0);
 361         csum_tree_block(NULL, buf, 0);
 362         ret = pwrite(fd, buf->data, leafsize, blocks[5]);
 363         BUG_ON(ret != leafsize);
 364
 365         /* and write out the super block */
 366         BUG_ON(sizeof(super) > sectorsize);
 367         memset(buf->data, 0, sectorsize);
 368         memcpy(buf->data, &super, sizeof(super));
 369         buf->len = sectorsize;
 370         csum_tree_block(NULL, buf, 0);
 371         ret = pwrite(fd, buf->data, sectorsize, blocks[0]);
 372         BUG_ON(ret != sectorsize);
 373
 374
 375         free(buf);
 376         return 0;
 377 }
 378
 379 static u64 device_size(int fd, struct stat *st)
 380 {
 381         u64 size;
 382         if (S_ISREG(st->st_mode)) {
 383                 return st->st_size;
 384         }
 385         if (!S_ISBLK(st->st_mode)) {
 386                 return 0;
 387         }
 388         if (ioctl(fd, BLKGETSIZE64, &size) >= 0) {
 389                 return size;
 390         }
 391         return 0;
 392 }
 393
 394 static int zero_blocks(int fd, off_t start, size_t len)
 395 {
 396         char *buf = malloc(len);
 397         int ret = 0;
 398         ssize_t written;
 399
 400         if (!buf)
 401                 return -ENOMEM;
 402         memset(buf, 0, len);
 403         written = pwrite(fd, buf, len, start);
 404         if (written != len)
 405                 ret = -EIO;
 406         free(buf);
 407         return ret;
 408 }
 409
 410 static int zero_dev_start(int fd)
 411 {
 412         off_t start = 0;
 413         size_t len = 2 * 1024 * 1024;
 414
 415 #ifdef __sparc__
 416         /* don't overwrite the disk labels on sparc */
 417         start = 1024;
 418         len -= 1024;
 419 #endif
 420         return zero_blocks(fd, start, len);
 421 }
 422
 423 static int zero_dev_end(int fd, u64 dev_size)
 424 {
 425         size_t len = 2 * 1024 * 1024;
 426         off_t start = dev_size - len;
 427
 428         return zero_blocks(fd, start, len);
 429 }
 430
 431 int btrfs_add_to_fsid(struct btrfs_trans_handle *trans,
 432                       struct btrfs_root *root, int fd, u64 block_count,
 433                       u32 io_width, u32 io_align, u32 sectorsize)
 434 {
 435         struct btrfs_super_block *disk_super;
 436         struct btrfs_super_block *super = &root->fs_info->super_copy;
 437         struct btrfs_device *device;
 438         struct btrfs_dev_item *dev_item;
 439         char *buf;
 440         u64 total_bytes;
 441         u64 num_devs;
 442         int ret;
 443
 444         device = kmalloc(sizeof(*device), GFP_NOFS);
 445         if (!device)
 446                 return -ENOMEM;
 447         buf = kmalloc(sectorsize, GFP_NOFS);
 448         if (!buf) {
 449                 kfree(device);
 450                 return -ENOMEM;
 451         }
 452         BUG_ON(sizeof(*disk_super) > sectorsize);
 453         memset(buf, 0, sectorsize);
 454
 455         disk_super = (struct btrfs_super_block *)buf;
 456         dev_item = &disk_super->dev_item;
 457
 458         uuid_generate(device->uuid);
 459         device->devid = 0;
 460         device->type = 0;
 461         device->io_width = io_width;
 462         device->io_align = io_align;
 463         device->sector_size = sectorsize;
 464         device->fd = fd;
 465         device->total_bytes = block_count;
 466         device->bytes_used = 0;
 467         device->total_ios = 0;
 468         device->dev_root = root->fs_info->dev_root;
 469
 470         ret = btrfs_add_device(trans, root, device);
 471         BUG_ON(ret);
 472
 473         total_bytes = btrfs_super_total_bytes(super) + block_count;
 474         btrfs_set_super_total_bytes(super, total_bytes);
 475
 476         num_devs = btrfs_super_num_devices(super) + 1;
 477         btrfs_set_super_num_devices(super, num_devs);
 478
 479         memcpy(disk_super, super, sizeof(*disk_super));
 480
 481         printf("adding device id %llu\n", (unsigned long long)device->devid);
 482         btrfs_set_stack_device_id(dev_item, device->devid);
 483         btrfs_set_stack_device_type(dev_item, device->type);
 484         btrfs_set_stack_device_io_align(dev_item, device->io_align);
 485         btrfs_set_stack_device_io_width(dev_item, device->io_width);
 486         btrfs_set_stack_device_sector_size(dev_item, device->sector_size);
 487         btrfs_set_stack_device_total_bytes(dev_item, device->total_bytes);
 488         btrfs_set_stack_device_bytes_used(dev_item, device->bytes_used);
 489         memcpy(&dev_item->uuid, device->uuid, BTRFS_UUID_SIZE);
 490
 491         ret = pwrite(fd, buf, sectorsize, BTRFS_SUPER_INFO_OFFSET);
 492         BUG_ON(ret != sectorsize);
 493
 494         kfree(buf);
 495         list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
 496         ret = btrfs_bootstrap_super_map(&root->fs_info->mapping_tree,
 497                                         root->fs_info->fs_devices);
 498         BUG_ON(ret);
 499         return 0;
 500 }
 501
 502 int btrfs_prepare_device(int fd, char *file, int zero_end, u64 *block_count_ret)
 503 {
 504         u64 block_count;
 505         struct stat st;
 506         int ret;
 507
 508         ret = fstat(fd, &st);
 509         if (ret < 0) {
 510                 fprintf(stderr, "unable to stat %s\n", file);
 511                 exit(1);
 512         }
 513
 514         block_count = device_size(fd, &st);
 515         if (block_count == 0) {
 516                 fprintf(stderr, "unable to find %s size\n", file);
 517                 exit(1);
 518         }
 519         zero_end = 1;
 520
 521         if (block_count < 256 * 1024 * 1024) {
 522                 fprintf(stderr, "device %s is too small\n", file);
 523                 exit(1);
 524         }
 525         ret = zero_dev_start(fd);
 526         if (ret) {
 527                 fprintf(stderr, "failed to zero device start %d\n", ret);
 528                 exit(1);
 529         }
 530
 531         if (zero_end) {
 532                 ret = zero_dev_end(fd, block_count);
 533                 if (ret) {
 534                         fprintf(stderr, "failed to zero device end %d\n", ret);
 535                         exit(1);
 536                 }
 537         }
 538         *block_count_ret = block_count;
 539         return 0;
 540 }
 541
 542 int btrfs_make_root_dir(struct btrfs_trans_handle *trans,
 543                         struct btrfs_root *root, u64 objectid)
 544 {
 545         int ret;
 546         struct btrfs_inode_item inode_item;
 547
 548         memset(&inode_item, 0, sizeof(inode_item));
 549         btrfs_set_stack_inode_generation(&inode_item, trans->transid);
 550         btrfs_set_stack_inode_size(&inode_item, 0);
 551         btrfs_set_stack_inode_nlink(&inode_item, 1);
 552         btrfs_set_stack_inode_nblocks(&inode_item, 1);
 553         btrfs_set_stack_inode_mode(&inode_item, S_IFDIR | 0555);
 554
 555         if (root->fs_info->tree_root == root)
 556                 btrfs_set_super_root_dir(&root->fs_info->super_copy, objectid);
 557
 558         ret = btrfs_insert_inode(trans, root, objectid, &inode_item);
 559         if (ret)
 560                 goto error;
 561
 562         ret = btrfs_insert_inode_ref(trans, root, "..", 2, objectid, objectid);
 563         if (ret)
 564                 goto error;
 565
 566         btrfs_set_root_dirid(&root->root_item, objectid);
 567         ret = 0;
 568 error:
 569         return ret;
 570 }
 571
 572 /*
 573  * returns 1 if the device was mounted, < 0 on error or 0 if everything
 574  * is safe to continue.  TODO, this should also scan multi-device filesystems
 575  */
 576 int check_mounted(char *file)
 577 {
 578         struct mntent *mnt;
 579         struct stat st_buf;
 580         dev_t file_dev = 0;
 581         dev_t file_rdev = 0;
 582         ino_t file_ino = 0;
 583         FILE *f;
 584         int ret = 0;
 585
 586         if ((f = setmntent ("/proc/mounts", "r")) == NULL)
 587                 return -errno;
 588
 589         if (stat(file, &st_buf) < 0) {
 590                 return -errno;
 591         } else {
 592                 if (S_ISBLK(st_buf.st_mode)) {
 593                         file_rdev = st_buf.st_rdev;
 594                 } else {
 595                         file_dev = st_buf.st_dev;
 596                         file_ino = st_buf.st_ino;
 597                 }
 598         }
 599
 600         while ((mnt = getmntent (f)) != NULL) {
 601                 if (strcmp(file, mnt->mnt_fsname) == 0)
 602                         break;
 603
 604                 if (stat(mnt->mnt_fsname, &st_buf) == 0) {
 605                         if (S_ISBLK(st_buf.st_mode)) {
 606                                 if (file_rdev && (file_rdev == st_buf.st_rdev))
 607                                         break;
 608                         } else if (file_dev && ((file_dev == st_buf.st_dev) &&
 609                                                 (file_ino == st_buf.st_ino))) {
 610                                         break;
 611                         }
 612                 }
 613         }
 614
 615         if (mnt) {
 616                 /* found an entry in mnt table */
 617                 ret = 1;
 618         }
 619
 620         endmntent (f);
 621         return ret;
 622 }
 623
 624 struct pending_dir {
 625         struct list_head list;
 626         char name[256];
 627 };
 628
 629 int btrfs_register_one_device(char *fname)
 630 {
 631         struct btrfs_ioctl_vol_args args;
 632         int fd;
 633         int ret;
 634
 635         fd = open("/dev/btrfs-control", O_RDONLY);
 636         if (fd < 0)
 637                 return -EINVAL;
 638         strcpy(args.name, fname);
 639         ret = ioctl(fd, BTRFS_IOC_SCAN_DEV, &args);
 640         close(fd);
 641         return ret;
 642 }
 643
 644 int btrfs_scan_one_dir(char *dirname, int run_ioctl)
 645 {
 646         DIR *dirp;
 647         struct dirent *dirent;
 648         struct pending_dir *pending;
 649         struct stat st;
 650         int ret;
 651         int fd;
 652         int dirname_len;
 653         int pathlen;
 654         char *fullpath;
 655         struct list_head pending_list;
 656         struct btrfs_fs_devices *tmp_devices;
 657         u64 num_devices;
 658
 659         INIT_LIST_HEAD(&pending_list);
 660
 661         pending = malloc(sizeof(*pending));
 662         if (!pending)
 663                 return -ENOMEM;
 664         strcpy(pending->name, dirname);
 665
 666 again:
 667         dirname_len = strlen(pending->name);
 668         pathlen = 1024;
 669         fullpath = malloc(pathlen);
 670         dirname = pending->name;
 671
 672         if (!fullpath) {
 673                 ret = -ENOMEM;
 674                 goto fail;
 675         }
 676         dirp = opendir(dirname);
 677         if (!dirp) {
 678                 fprintf(stderr, "Unable to open /sys/block for scanning\n");
 679                 return -ENOENT;
 680         }
 681         while(1) {
 682                 dirent = readdir(dirp);
 683                 if (!dirent)
 684                         break;
 685                 if (dirent->d_name[0] == '.')
 686                         continue;
 687                 if (dirname_len + strlen(dirent->d_name) + 2 > pathlen) {
 688                         ret = -EFAULT;
 689                         goto fail;
 690                 }
 691                 snprintf(fullpath, pathlen, "%s/%s", dirname, dirent->d_name);
 692                 ret = lstat(fullpath, &st);
 693                 if (ret < 0) {
 694                         fprintf(stderr, "failed to stat %s\n", fullpath);
 695                         continue;
 696                 }
 697                 if (S_ISLNK(st.st_mode))
 698                         continue;
 699                 if (S_ISDIR(st.st_mode)) {
 700                         struct pending_dir *next = malloc(sizeof(*next));
 701                         if (!next) {
 702                                 ret = -ENOMEM;
 703                                 goto fail;
 704                         }
 705                         strcpy(next->name, fullpath);
 706                         list_add_tail(&next->list, &pending_list);
 707                 }
 708                 if (!S_ISBLK(st.st_mode)) {
 709                         continue;
 710                 }
 711                 fd = open(fullpath, O_RDONLY);
 712                 if (fd < 0) {
 713                         fprintf(stderr, "failed to read %s\n", fullpath);
 714                         continue;
 715                 }
 716                 ret = btrfs_scan_one_device(fd, fullpath, &tmp_devices,
 717                                             &num_devices,
 718                                             BTRFS_SUPER_INFO_OFFSET);
 719                 if (ret == 0 && run_ioctl > 0) {
 720                         btrfs_register_one_device(fullpath);
 721                 }
 722                 close(fd);
 723         }
 724         if (!list_empty(&pending_list)) {
 725                 free(pending);
 726                 pending = list_entry(pending_list.next, struct pending_dir,
 727                                      list);
 728                 list_del(&pending->list);
 729                 closedir(dirp);
 730                 goto again;
 731         }
 732         ret = 0;
 733 fail:
 734         free(pending);
 735         closedir(dirp);
 736         return ret;
 737 }
 738
 739 int btrfs_scan_for_fsid(struct btrfs_fs_devices *fs_devices, u64 total_devs,
 740                         int run_ioctls)
 741 {
 742         return btrfs_scan_one_dir("/dev", run_ioctls);
 743 }