volumes.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 #define _XOPEN_SOURCE 600
  19 #define __USE_XOPEN2K
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <sys/types.h>
  23 #include <sys/stat.h>
  24 #include <uuid/uuid.h>
  25 #include <fcntl.h>
  26 #include <unistd.h>
  27 #include "ctree.h"
  28 #include "disk-io.h"
  29 #include "transaction.h"
  30 #include "print-tree.h"
  31 #include "volumes.h"
  32
  33 struct stripe {
  34         struct btrfs_device *dev;
  35         u64 physical;
  36 };
  37
  38 struct map_lookup {
  39         struct cache_extent ce;
  40         u64 type;
  41         int io_align;
  42         int io_width;
  43         int stripe_len;
  44         int sector_size;
  45         int num_stripes;
  46         int sub_stripes;
  47         struct btrfs_bio_stripe stripes[];
  48 };
  49
  50 #define map_lookup_size(n) (sizeof(struct map_lookup) + \
  51                             (sizeof(struct btrfs_bio_stripe) * (n)))
  52
  53 static LIST_HEAD(fs_uuids);
  54
  55 static struct btrfs_device *__find_device(struct list_head *head, u64 devid,
  56                                           u8 *uuid)
  57 {
  58         struct btrfs_device *dev;
  59         struct list_head *cur;
  60
  61         list_for_each(cur, head) {
  62                 dev = list_entry(cur, struct btrfs_device, dev_list);
  63                 if (dev->devid == devid &&
  64                     !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE)) {
  65                         return dev;
  66                 }
  67         }
  68         return NULL;
  69 }
  70
  71 static struct btrfs_fs_devices *find_fsid(u8 *fsid)
  72 {
  73         struct list_head *cur;
  74         struct btrfs_fs_devices *fs_devices;
  75
  76         list_for_each(cur, &fs_uuids) {
  77                 fs_devices = list_entry(cur, struct btrfs_fs_devices, list);
  78                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
  79                         return fs_devices;
  80         }
  81         return NULL;
  82 }
  83
  84 static int device_list_add(const char *path,
  85                            struct btrfs_super_block *disk_super,
  86                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
  87 {
  88         struct btrfs_device *device;
  89         struct btrfs_fs_devices *fs_devices;
  90         u64 found_transid = btrfs_super_generation(disk_super);
  91
  92         fs_devices = find_fsid(disk_super->fsid);
  93         if (!fs_devices) {
  94                 fs_devices = kmalloc(sizeof(*fs_devices), GFP_NOFS);
  95                 if (!fs_devices)
  96                         return -ENOMEM;
  97                 INIT_LIST_HEAD(&fs_devices->devices);
  98                 list_add(&fs_devices->list, &fs_uuids);
  99                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
 100                 fs_devices->latest_devid = devid;
 101                 fs_devices->latest_trans = found_transid;
 102                 fs_devices->lowest_devid = (u64)-1;
 103                 device = NULL;
 104         } else {
 105                 device = __find_device(&fs_devices->devices, devid,
 106                                        disk_super->dev_item.uuid);
 107         }
 108         if (!device) {
 109                 device = kzalloc(sizeof(*device), GFP_NOFS);
 110                 if (!device) {
 111                         /* we can safely leave the fs_devices entry around */
 112                         return -ENOMEM;
 113                 }
 114                 device->devid = devid;
 115                 memcpy(device->uuid, disk_super->dev_item.uuid,
 116                        BTRFS_UUID_SIZE);
 117                 device->name = kstrdup(path, GFP_NOFS);
 118                 if (!device->name) {
 119                         kfree(device);
 120                         return -ENOMEM;
 121                 }
 122                 device->label = kstrdup(disk_super->label, GFP_NOFS);
 123                 device->total_devs = btrfs_super_num_devices(disk_super);
 124                 device->super_bytes_used = btrfs_super_bytes_used(disk_super);
 125                 device->total_bytes =
 126                         btrfs_stack_device_total_bytes(&disk_super->dev_item);
 127                 device->bytes_used =
 128                         btrfs_stack_device_bytes_used(&disk_super->dev_item);
 129                 list_add(&device->dev_list, &fs_devices->devices);
 130         }
 131
 132         if (found_transid > fs_devices->latest_trans) {
 133                 fs_devices->latest_devid = devid;
 134                 fs_devices->latest_trans = found_transid;
 135         }
 136         if (fs_devices->lowest_devid > devid) {
 137                 fs_devices->lowest_devid = devid;
 138         }
 139         *fs_devices_ret = fs_devices;
 140         return 0;
 141 }
 142
 143 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 144 {
 145         struct list_head *head = &fs_devices->devices;
 146         struct list_head *cur;
 147         struct btrfs_device *device;
 148
 149         list_for_each(cur, head) {
 150                 device = list_entry(cur, struct btrfs_device, dev_list);
 151                 close(device->fd);
 152                 device->fd = -1;
 153         }
 154         return 0;
 155 }
 156
 157 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, int flags)
 158 {
 159         int fd;
 160         struct list_head *head = &fs_devices->devices;
 161         struct list_head *cur;
 162         struct btrfs_device *device;
 163         int ret;
 164
 165         list_for_each(cur, head) {
 166                 device = list_entry(cur, struct btrfs_device, dev_list);
 167
 168                 fd = open(device->name, flags);
 169                 if (fd < 0) {
 170                         ret = -errno;
 171                         goto fail;
 172                 }
 173
 174                 if (device->devid == fs_devices->latest_devid)
 175                         fs_devices->latest_bdev = fd;
 176                 if (device->devid == fs_devices->lowest_devid)
 177                         fs_devices->lowest_bdev = fd;
 178                 device->fd = fd;
 179         }
 180         return 0;
 181 fail:
 182         btrfs_close_devices(fs_devices);
 183         return ret;
 184 }
 185
 186 int btrfs_scan_one_device(int fd, const char *path,
 187                           struct btrfs_fs_devices **fs_devices_ret,
 188                           u64 *total_devs, u64 super_offset)
 189 {
 190         struct btrfs_super_block *disk_super;
 191         char *buf;
 192         int ret;
 193         u64 devid;
 194         char uuidbuf[37];
 195
 196         buf = malloc(4096);
 197         if (!buf) {
 198                 ret = -ENOMEM;
 199                 goto error;
 200         }
 201         ret = pread(fd, buf, 4096, super_offset);
 202         if (ret != 4096) {
 203                 ret = -EIO;
 204                 goto error;
 205         }
 206         disk_super = (struct btrfs_super_block *)buf;
 207         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
 208             sizeof(disk_super->magic))) {
 209                 ret = -ENOENT;
 210                 goto error_brelse;
 211         }
 212         devid = le64_to_cpu(disk_super->dev_item.devid);
 213         *total_devs = btrfs_super_num_devices(disk_super);
 214         uuid_unparse(disk_super->fsid, uuidbuf);
 215
 216         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 217
 218 error_brelse:
 219         free(buf);
 220 error:
 221         return ret;
 222 }
 223
 224 /*
 225  * this uses a pretty simple search, the expectation is that it is
 226  * called very infrequently and that a given device has a small number
 227  * of extents
 228  */
 229 static int find_free_dev_extent(struct btrfs_trans_handle *trans,
 230                                 struct btrfs_device *device,
 231                                 struct btrfs_path *path,
 232                                 u64 num_bytes, u64 *start)
 233 {
 234         struct btrfs_key key;
 235         struct btrfs_root *root = device->dev_root;
 236         struct btrfs_dev_extent *dev_extent = NULL;
 237         u64 hole_size = 0;
 238         u64 last_byte = 0;
 239         u64 search_start = 0;
 240         u64 search_end = device->total_bytes;
 241         int ret;
 242         int slot = 0;
 243         int start_found;
 244         struct extent_buffer *l;
 245
 246         start_found = 0;
 247         path->reada = 2;
 248
 249         /* FIXME use last free of some kind */
 250
 251         /* we don't want to overwrite the superblock on the drive,
 252          * so we make sure to start at an offset of at least 1MB
 253          */
 254         search_start = max((u64)1024 * 1024, search_start);
 255         key.objectid = device->devid;
 256         key.offset = search_start;
 257         key.type = BTRFS_DEV_EXTENT_KEY;
 258         ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
 259         if (ret < 0)
 260                 goto error;
 261         ret = btrfs_previous_item(root, path, 0, key.type);
 262         if (ret < 0)
 263                 goto error;
 264         l = path->nodes[0];
 265         btrfs_item_key_to_cpu(l, &key, path->slots[0]);
 266         while (1) {
 267                 l = path->nodes[0];
 268                 slot = path->slots[0];
 269                 if (slot >= btrfs_header_nritems(l)) {
 270                         ret = btrfs_next_leaf(root, path);
 271                         if (ret == 0)
 272                                 continue;
 273                         if (ret < 0)
 274                                 goto error;
 275 no_more_items:
 276                         if (!start_found) {
 277                                 if (search_start >= search_end) {
 278                                         ret = -ENOSPC;
 279                                         goto error;
 280                                 }
 281                                 *start = search_start;
 282                                 start_found = 1;
 283                                 goto check_pending;
 284                         }
 285                         *start = last_byte > search_start ?
 286                                 last_byte : search_start;
 287                         if (search_end <= *start) {
 288                                 ret = -ENOSPC;
 289                                 goto error;
 290                         }
 291                         goto check_pending;
 292                 }
 293                 btrfs_item_key_to_cpu(l, &key, slot);
 294
 295                 if (key.objectid < device->devid)
 296                         goto next;
 297
 298                 if (key.objectid > device->devid)
 299                         goto no_more_items;
 300
 301                 if (key.offset >= search_start && key.offset > last_byte &&
 302                     start_found) {
 303                         if (last_byte < search_start)
 304                                 last_byte = search_start;
 305                         hole_size = key.offset - last_byte;
 306                         if (key.offset > last_byte &&
 307                             hole_size >= num_bytes) {
 308                                 *start = last_byte;
 309                                 goto check_pending;
 310                         }
 311                 }
 312                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY) {
 313                         goto next;
 314                 }
 315
 316                 start_found = 1;
 317                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 318                 last_byte = key.offset + btrfs_dev_extent_length(l, dev_extent);
 319 next:
 320                 path->slots[0]++;
 321                 cond_resched();
 322         }
 323 check_pending:
 324         /* we have to make sure we didn't find an extent that has already
 325          * been allocated by the map tree or the original allocation
 326          */
 327         btrfs_release_path(root, path);
 328         BUG_ON(*start < search_start);
 329
 330         if (*start + num_bytes > search_end) {
 331                 ret = -ENOSPC;
 332                 goto error;
 333         }
 334         /* check for pending inserts here */
 335         return 0;
 336
 337 error:
 338         btrfs_release_path(root, path);
 339         return ret;
 340 }
 341
 342 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
 343                            struct btrfs_device *device,
 344                            u64 chunk_tree, u64 chunk_objectid,
 345                            u64 chunk_offset,
 346                            u64 num_bytes, u64 *start)
 347 {
 348         int ret;
 349         struct btrfs_path *path;
 350         struct btrfs_root *root = device->dev_root;
 351         struct btrfs_dev_extent *extent;
 352         struct extent_buffer *leaf;
 353         struct btrfs_key key;
 354
 355         path = btrfs_alloc_path();
 356         if (!path)
 357                 return -ENOMEM;
 358
 359         ret = find_free_dev_extent(trans, device, path, num_bytes, start);
 360         if (ret) {
 361                 goto err;
 362         }
 363
 364         key.objectid = device->devid;
 365         key.offset = *start;
 366         key.type = BTRFS_DEV_EXTENT_KEY;
 367         ret = btrfs_insert_empty_item(trans, root, path, &key,
 368                                       sizeof(*extent));
 369         BUG_ON(ret);
 370
 371         leaf = path->nodes[0];
 372         extent = btrfs_item_ptr(leaf, path->slots[0],
 373                                 struct btrfs_dev_extent);
 374         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
 375         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
 376         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
 377
 378         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
 379                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
 380                     BTRFS_UUID_SIZE);
 381
 382         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
 383         btrfs_mark_buffer_dirty(leaf);
 384 err:
 385         btrfs_free_path(path);
 386         return ret;
 387 }
 388
 389 static int find_next_chunk(struct btrfs_root *root, u64 objectid, u64 *offset)
 390 {
 391         struct btrfs_path *path;
 392         int ret;
 393         struct btrfs_key key;
 394         struct btrfs_chunk *chunk;
 395         struct btrfs_key found_key;
 396
 397         path = btrfs_alloc_path();
 398         BUG_ON(!path);
 399
 400         key.objectid = objectid;
 401         key.offset = (u64)-1;
 402         key.type = BTRFS_CHUNK_ITEM_KEY;
 403
 404         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 405         if (ret < 0)
 406                 goto error;
 407
 408         BUG_ON(ret == 0);
 409
 410         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
 411         if (ret) {
 412                 *offset = 0;
 413         } else {
 414                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 415                                       path->slots[0]);
 416                 if (found_key.objectid != objectid)
 417                         *offset = 0;
 418                 else {
 419                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
 420                                                struct btrfs_chunk);
 421                         *offset = found_key.offset +
 422                                 btrfs_chunk_length(path->nodes[0], chunk);
 423                 }
 424         }
 425         ret = 0;
 426 error:
 427         btrfs_free_path(path);
 428         return ret;
 429 }
 430
 431 static int find_next_devid(struct btrfs_root *root, struct btrfs_path *path,
 432                            u64 *objectid)
 433 {
 434         int ret;
 435         struct btrfs_key key;
 436         struct btrfs_key found_key;
 437
 438         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
 439         key.type = BTRFS_DEV_ITEM_KEY;
 440         key.offset = (u64)-1;
 441
 442         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 443         if (ret < 0)
 444                 goto error;
 445
 446         BUG_ON(ret == 0);
 447
 448         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
 449                                   BTRFS_DEV_ITEM_KEY);
 450         if (ret) {
 451                 *objectid = 1;
 452         } else {
 453                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 454                                       path->slots[0]);
 455                 *objectid = found_key.offset + 1;
 456         }
 457         ret = 0;
 458 error:
 459         btrfs_release_path(root, path);
 460         return ret;
 461 }
 462
 463 /*
 464  * the device information is stored in the chunk root
 465  * the btrfs_device struct should be fully filled in
 466  */
 467 int btrfs_add_device(struct btrfs_trans_handle *trans,
 468                      struct btrfs_root *root,
 469                      struct btrfs_device *device)
 470 {
 471         int ret;
 472         struct btrfs_path *path;
 473         struct btrfs_dev_item *dev_item;
 474         struct extent_buffer *leaf;
 475         struct btrfs_key key;
 476         unsigned long ptr;
 477         u64 free_devid;
 478
 479         root = root->fs_info->chunk_root;
 480
 481         path = btrfs_alloc_path();
 482         if (!path)
 483                 return -ENOMEM;
 484
 485         ret = find_next_devid(root, path, &free_devid);
 486         if (ret)
 487                 goto out;
 488
 489         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
 490         key.type = BTRFS_DEV_ITEM_KEY;
 491         key.offset = free_devid;
 492
 493         ret = btrfs_insert_empty_item(trans, root, path, &key,
 494                                       sizeof(*dev_item));
 495         if (ret)
 496                 goto out;
 497
 498         leaf = path->nodes[0];
 499         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
 500
 501         device->devid = free_devid;
 502         btrfs_set_device_id(leaf, dev_item, device->devid);
 503         btrfs_set_device_type(leaf, dev_item, device->type);
 504         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
 505         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
 506         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
 507         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
 508         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
 509         btrfs_set_device_group(leaf, dev_item, 0);
 510         btrfs_set_device_seek_speed(leaf, dev_item, 0);
 511         btrfs_set_device_bandwidth(leaf, dev_item, 0);
 512
 513         ptr = (unsigned long)btrfs_device_uuid(dev_item);
 514         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
 515         btrfs_mark_buffer_dirty(leaf);
 516         ret = 0;
 517
 518 out:
 519         btrfs_free_path(path);
 520         return ret;
 521 }
 522
 523 int btrfs_update_device(struct btrfs_trans_handle *trans,
 524                         struct btrfs_device *device)
 525 {
 526         int ret;
 527         struct btrfs_path *path;
 528         struct btrfs_root *root;
 529         struct btrfs_dev_item *dev_item;
 530         struct extent_buffer *leaf;
 531         struct btrfs_key key;
 532
 533         root = device->dev_root->fs_info->chunk_root;
 534
 535         path = btrfs_alloc_path();
 536         if (!path)
 537                 return -ENOMEM;
 538
 539         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
 540         key.type = BTRFS_DEV_ITEM_KEY;
 541         key.offset = device->devid;
 542
 543         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
 544         if (ret < 0)
 545                 goto out;
 546
 547         if (ret > 0) {
 548                 ret = -ENOENT;
 549                 goto out;
 550         }
 551
 552         leaf = path->nodes[0];
 553         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
 554
 555         btrfs_set_device_id(leaf, dev_item, device->devid);
 556         btrfs_set_device_type(leaf, dev_item, device->type);
 557         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
 558         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
 559         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
 560         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
 561         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
 562         btrfs_mark_buffer_dirty(leaf);
 563
 564 out:
 565         btrfs_free_path(path);
 566         return ret;
 567 }
 568
 569 int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
 570                            struct btrfs_root *root,
 571                            struct btrfs_key *key,
 572                            struct btrfs_chunk *chunk, int item_size)
 573 {
 574         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
 575         struct btrfs_disk_key disk_key;
 576         u32 array_size;
 577         u8 *ptr;
 578
 579         array_size = btrfs_super_sys_array_size(super_copy);
 580         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
 581                 return -EFBIG;
 582
 583         ptr = super_copy->sys_chunk_array + array_size;
 584         btrfs_cpu_key_to_disk(&disk_key, key);
 585         memcpy(ptr, &disk_key, sizeof(disk_key));
 586         ptr += sizeof(disk_key);
 587         memcpy(ptr, chunk, item_size);
 588         item_size += sizeof(disk_key);
 589         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
 590         return 0;
 591 }
 592
 593 static u64 div_factor(u64 num, int factor)
 594 {
 595         if (factor == 10)
 596                 return num;
 597         num *= factor;
 598         return num / 10;
 599 }
 600
 601 static u64 chunk_bytes_by_type(u64 type, u64 calc_size, int num_stripes,
 602                                int sub_stripes)
 603 {
 604         if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
 605                 return calc_size;
 606         else if (type & BTRFS_BLOCK_GROUP_RAID10)
 607                 return calc_size * (num_stripes / sub_stripes);
 608         else
 609                 return calc_size * num_stripes;
 610 }
 611
 612
 613 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 614                       struct btrfs_root *extent_root, u64 *start,
 615                       u64 *num_bytes, u64 type)
 616 {
 617         u64 dev_offset;
 618         struct btrfs_fs_info *info = extent_root->fs_info;
 619         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
 620         struct btrfs_stripe *stripes;
 621         struct btrfs_device *device = NULL;
 622         struct btrfs_chunk *chunk;
 623         struct list_head private_devs;
 624         struct list_head *dev_list = &extent_root->fs_info->fs_devices->devices;
 625         struct list_head *cur;
 626         struct map_lookup *map;
 627         int min_stripe_size = 1 * 1024 * 1024;
 628         u64 physical;
 629         u64 calc_size = 8 * 1024 * 1024;
 630         u64 min_free;
 631         u64 max_chunk_size = 4 * calc_size;
 632         u64 avail;
 633         u64 max_avail = 0;
 634         u64 percent_max;
 635         int num_stripes = 1;
 636         int min_stripes = 1;
 637         int sub_stripes = 0;
 638         int looped = 0;
 639         int ret;
 640         int index;
 641         int stripe_len = 64 * 1024;
 642         struct btrfs_key key;
 643
 644         if (list_empty(dev_list)) {
 645                 return -ENOSPC;
 646         }
 647
 648         if (type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
 649                     BTRFS_BLOCK_GROUP_RAID10 |
 650                     BTRFS_BLOCK_GROUP_DUP)) {
 651                 if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
 652                         calc_size = 8 * 1024 * 1024;
 653                         max_chunk_size = calc_size * 2;
 654                         min_stripe_size = 1 * 1024 * 1024;
 655                 } else if (type & BTRFS_BLOCK_GROUP_DATA) {
 656                         calc_size = 1024 * 1024 * 1024;
 657                         max_chunk_size = 10 * calc_size;
 658                         min_stripe_size = 64 * 1024 * 1024;
 659                 } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
 660                         calc_size = 1024 * 1024 * 1024;
 661                         max_chunk_size = 4 * calc_size;
 662                         min_stripe_size = 32 * 1024 * 1024;
 663                 }
 664         }
 665         if (type & BTRFS_BLOCK_GROUP_RAID1) {
 666                 num_stripes = min_t(u64, 2,
 667                                   btrfs_super_num_devices(&info->super_copy));
 668                 if (num_stripes < 2)
 669                         return -ENOSPC;
 670                 min_stripes = 2;
 671         }
 672         if (type & BTRFS_BLOCK_GROUP_DUP) {
 673                 num_stripes = 2;
 674                 min_stripes = 2;
 675         }
 676         if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
 677                 num_stripes = btrfs_super_num_devices(&info->super_copy);
 678                 min_stripes = 2;
 679         }
 680         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
 681                 num_stripes = btrfs_super_num_devices(&info->super_copy);
 682                 if (num_stripes < 4)
 683                         return -ENOSPC;
 684                 num_stripes &= ~(u32)1;
 685                 sub_stripes = 2;
 686                 min_stripes = 4;
 687         }
 688
 689         /* we don't want a chunk larger than 10% of the FS */
 690         percent_max = div_factor(btrfs_super_total_bytes(&info->super_copy), 1);
 691         max_chunk_size = min(percent_max, max_chunk_size);
 692
 693 again:
 694         if (chunk_bytes_by_type(type, calc_size, num_stripes, sub_stripes) >
 695             max_chunk_size) {
 696                 calc_size = max_chunk_size;
 697                 calc_size /= num_stripes;
 698                 calc_size /= stripe_len;
 699                 calc_size *= stripe_len;
 700         }
 701         /* we don't want tiny stripes */
 702         calc_size = max_t(u64, calc_size, min_stripe_size);
 703
 704         calc_size /= stripe_len;
 705         calc_size *= stripe_len;
 706         INIT_LIST_HEAD(&private_devs);
 707         cur = dev_list->next;
 708         index = 0;
 709
 710         if (type & BTRFS_BLOCK_GROUP_DUP)
 711                 min_free = calc_size * 2;
 712         else
 713                 min_free = calc_size;
 714
 715         /* build a private list of devices we will allocate from */
 716         while(index < num_stripes) {
 717                 device = list_entry(cur, struct btrfs_device, dev_list);
 718                 avail = device->total_bytes - device->bytes_used;
 719                 cur = cur->next;
 720                 if (avail >= min_free) {
 721                         list_move_tail(&device->dev_list, &private_devs);
 722                         index++;
 723                         if (type & BTRFS_BLOCK_GROUP_DUP)
 724                                 index++;
 725                 } else if (avail > max_avail)
 726                         max_avail = avail;
 727                 if (cur == dev_list)
 728                         break;
 729         }
 730         if (index < num_stripes) {
 731                 list_splice(&private_devs, dev_list);
 732                 if (index >= min_stripes) {
 733                         num_stripes = index;
 734                         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
 735                                 num_stripes /= sub_stripes;
 736                                 num_stripes *= sub_stripes;
 737                         }
 738                         looped = 1;
 739                         goto again;
 740                 }
 741                 if (!looped && max_avail > 0) {
 742                         looped = 1;
 743                         calc_size = max_avail;
 744                         goto again;
 745                 }
 746                 return -ENOSPC;
 747         }
 748         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
 749         key.type = BTRFS_CHUNK_ITEM_KEY;
 750         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
 751                               &key.offset);
 752         if (ret)
 753                 return ret;
 754
 755         chunk = kmalloc(btrfs_chunk_item_size(num_stripes), GFP_NOFS);
 756         if (!chunk)
 757                 return -ENOMEM;
 758
 759         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
 760         if (!map) {
 761                 kfree(chunk);
 762                 return -ENOMEM;
 763         }
 764
 765         stripes = &chunk->stripe;
 766         *num_bytes = chunk_bytes_by_type(type, calc_size,
 767                                          num_stripes, sub_stripes);
 768         index = 0;
 769         while(index < num_stripes) {
 770                 struct btrfs_stripe *stripe;
 771                 BUG_ON(list_empty(&private_devs));
 772                 cur = private_devs.next;
 773                 device = list_entry(cur, struct btrfs_device, dev_list);
 774
 775                 /* loop over this device again if we're doing a dup group */
 776                 if (!(type & BTRFS_BLOCK_GROUP_DUP) ||
 777                     (index == num_stripes - 1))
 778                         list_move_tail(&device->dev_list, dev_list);
 779
 780                 ret = btrfs_alloc_dev_extent(trans, device,
 781                              info->chunk_root->root_key.objectid,
 782                              BTRFS_FIRST_CHUNK_TREE_OBJECTID, key.offset,
 783                              calc_size, &dev_offset);
 784                 BUG_ON(ret);
 785
 786                 device->bytes_used += calc_size;
 787                 ret = btrfs_update_device(trans, device);
 788                 BUG_ON(ret);
 789
 790                 map->stripes[index].dev = device;
 791                 map->stripes[index].physical = dev_offset;
 792                 stripe = stripes + index;
 793                 btrfs_set_stack_stripe_devid(stripe, device->devid);
 794                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
 795                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
 796                 physical = dev_offset;
 797                 index++;
 798         }
 799         BUG_ON(!list_empty(&private_devs));
 800
 801         /* key was set above */
 802         btrfs_set_stack_chunk_length(chunk, *num_bytes);
 803         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
 804         btrfs_set_stack_chunk_stripe_len(chunk, stripe_len);
 805         btrfs_set_stack_chunk_type(chunk, type);
 806         btrfs_set_stack_chunk_num_stripes(chunk, num_stripes);
 807         btrfs_set_stack_chunk_io_align(chunk, stripe_len);
 808         btrfs_set_stack_chunk_io_width(chunk, stripe_len);
 809         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
 810         btrfs_set_stack_chunk_sub_stripes(chunk, sub_stripes);
 811         map->sector_size = extent_root->sectorsize;
 812         map->stripe_len = stripe_len;
 813         map->io_align = stripe_len;
 814         map->io_width = stripe_len;
 815         map->type = type;
 816         map->num_stripes = num_stripes;
 817         map->sub_stripes = sub_stripes;
 818
 819         ret = btrfs_insert_item(trans, chunk_root, &key, chunk,
 820                                 btrfs_chunk_item_size(num_stripes));
 821         BUG_ON(ret);
 822         *start = key.offset;;
 823
 824         map->ce.start = key.offset;
 825         map->ce.size = *num_bytes;
 826
 827         ret = insert_existing_cache_extent(
 828                            &extent_root->fs_info->mapping_tree.cache_tree,
 829                            &map->ce);
 830         BUG_ON(ret);
 831
 832         if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
 833                 ret = btrfs_add_system_chunk(trans, chunk_root, &key,
 834                                     chunk, btrfs_chunk_item_size(num_stripes));
 835                 BUG_ON(ret);
 836         }
 837
 838         kfree(chunk);
 839         return ret;
 840 }
 841
 842 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
 843 {
 844         cache_tree_init(&tree->cache_tree);
 845 }
 846
 847 int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
 848 {
 849         struct cache_extent *ce;
 850         struct map_lookup *map;
 851         int ret;
 852         u64 offset;
 853
 854         ce = find_first_cache_extent(&map_tree->cache_tree, logical);
 855         BUG_ON(!ce);
 856         BUG_ON(ce->start > logical || ce->start + ce->size < logical);
 857         map = container_of(ce, struct map_lookup, ce);
 858
 859         offset = logical - ce->start;
 860         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
 861                 ret = map->num_stripes;
 862         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
 863                 ret = map->sub_stripes;
 864         else
 865                 ret = 1;
 866         return ret;
 867 }
 868
 869 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
 870                     u64 logical, u64 *length,
 871                     struct btrfs_multi_bio **multi_ret, int mirror_num)
 872 {
 873         struct cache_extent *ce;
 874         struct map_lookup *map;
 875         u64 offset;
 876         u64 stripe_offset;
 877         u64 stripe_nr;
 878         int stripes_allocated = 8;
 879         int stripes_required = 1;
 880         int stripe_index;
 881         int i;
 882         struct btrfs_multi_bio *multi = NULL;
 883
 884         if (multi_ret && rw == READ) {
 885                 stripes_allocated = 1;
 886         }
 887 again:
 888         if (multi_ret) {
 889                 multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
 890                                 GFP_NOFS);
 891                 if (!multi)
 892                         return -ENOMEM;
 893         }
 894
 895         ce = find_first_cache_extent(&map_tree->cache_tree, logical);
 896         BUG_ON(!ce);
 897         BUG_ON(ce->start > logical || ce->start + ce->size < logical);
 898         map = container_of(ce, struct map_lookup, ce);
 899         offset = logical - ce->start;
 900
 901         if (rw == WRITE) {
 902                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
 903                                  BTRFS_BLOCK_GROUP_DUP)) {
 904                         stripes_required = map->num_stripes;
 905                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
 906                         stripes_required = map->sub_stripes;
 907                 }
 908         }
 909         /* if our multi bio struct is too small, back off and try again */
 910         if (multi_ret && rw == WRITE &&
 911             stripes_allocated < stripes_required) {
 912                 stripes_allocated = map->num_stripes;
 913                 kfree(multi);
 914                 goto again;
 915         }
 916         stripe_nr = offset;
 917         /*
 918          * stripe_nr counts the total number of stripes we have to stride
 919          * to get to this block
 920          */
 921         stripe_nr = stripe_nr / map->stripe_len;
 922
 923         stripe_offset = stripe_nr * map->stripe_len;
 924         BUG_ON(offset < stripe_offset);
 925
 926         /* stripe_offset is the offset of this block in its stripe*/
 927         stripe_offset = offset - stripe_offset;
 928
 929         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
 930                          BTRFS_BLOCK_GROUP_RAID10 |
 931                          BTRFS_BLOCK_GROUP_DUP)) {
 932                 /* we limit the length of each bio to what fits in a stripe */
 933                 *length = min_t(u64, ce->size - offset,
 934                               map->stripe_len - stripe_offset);
 935         } else {
 936                 *length = ce->size - offset;
 937         }
 938
 939         if (!multi_ret)
 940                 goto out;
 941
 942         multi->num_stripes = 1;
 943         stripe_index = 0;
 944         if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
 945                 if (rw == WRITE)
 946                         multi->num_stripes = map->num_stripes;
 947                 else if (mirror_num)
 948                         stripe_index = mirror_num - 1;
 949                 else
 950                         stripe_index = stripe_nr % map->num_stripes;
 951         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
 952                 int factor = map->num_stripes / map->sub_stripes;
 953
 954                 stripe_index = stripe_nr % factor;
 955                 stripe_index *= map->sub_stripes;
 956
 957                 if (rw == WRITE)
 958                         multi->num_stripes = map->sub_stripes;
 959                 else if (mirror_num)
 960                         stripe_index += mirror_num - 1;
 961                 else
 962                         stripe_index = stripe_nr % map->sub_stripes;
 963
 964                 stripe_nr = stripe_nr / factor;
 965         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
 966                 if (rw == WRITE)
 967                         multi->num_stripes = map->num_stripes;
 968                 else if (mirror_num)
 969                         stripe_index = mirror_num - 1;
 970         } else {
 971                 /*
 972                  * after this do_div call, stripe_nr is the number of stripes
 973                  * on this device we have to walk to find the data, and
 974                  * stripe_index is the number of our device in the stripe array
 975                  */
 976                 stripe_index = stripe_nr % map->num_stripes;
 977                 stripe_nr = stripe_nr / map->num_stripes;
 978         }
 979         BUG_ON(stripe_index >= map->num_stripes);
 980
 981         BUG_ON(stripe_index != 0 && multi->num_stripes > 1);
 982         for (i = 0; i < multi->num_stripes; i++) {
 983                 multi->stripes[i].physical =
 984                         map->stripes[stripe_index].physical + stripe_offset +
 985                         stripe_nr * map->stripe_len;
 986                 multi->stripes[i].dev = map->stripes[stripe_index].dev;
 987                 stripe_index++;
 988         }
 989         *multi_ret = multi;
 990 out:
 991         return 0;
 992 }
 993
 994 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
 995                                        u8 *uuid)
 996 {
 997         struct list_head *head = &root->fs_info->fs_devices->devices;
 998
 999         return __find_device(head, devid, uuid);
1000 }
1001
1002 int btrfs_bootstrap_super_map(struct btrfs_mapping_tree *map_tree,
1003                               struct btrfs_fs_devices *fs_devices)
1004 {
1005         struct map_lookup *map;
1006         u64 logical = BTRFS_SUPER_INFO_OFFSET;
1007         u64 length = BTRFS_SUPER_INFO_SIZE;
1008         int num_stripes = 0;
1009         int sub_stripes = 0;
1010         int ret;
1011         int i;
1012         struct list_head *cur;
1013
1014         list_for_each(cur, &fs_devices->devices) {
1015                 num_stripes++;
1016         }
1017         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
1018         if (!map)
1019                 return -ENOMEM;
1020
1021         map->ce.start = logical;
1022         map->ce.size = length;
1023         map->num_stripes = num_stripes;
1024         map->sub_stripes = sub_stripes;
1025         map->io_width = length;
1026         map->io_align = length;
1027         map->sector_size = length;
1028         map->stripe_len = length;
1029         map->type = BTRFS_BLOCK_GROUP_RAID1;
1030
1031         i = 0;
1032         list_for_each(cur, &fs_devices->devices) {
1033                 struct btrfs_device *device = list_entry(cur,
1034                                                          struct btrfs_device,
1035                                                          dev_list);
1036                 map->stripes[i].physical = logical;
1037                 map->stripes[i].dev = device;
1038                 i++;
1039         }
1040         ret = insert_existing_cache_extent(&map_tree->cache_tree, &map->ce);
1041         if (ret == -EEXIST) {
1042                 struct cache_extent *old;
1043                 struct map_lookup *old_map;
1044                 old = find_cache_extent(&map_tree->cache_tree, logical, length);
1045                 old_map = container_of(old, struct map_lookup, ce);
1046                 remove_cache_extent(&map_tree->cache_tree, old);
1047                 kfree(old_map);
1048                 ret = insert_existing_cache_extent(&map_tree->cache_tree,
1049                                                    &map->ce);
1050         }
1051         BUG_ON(ret);
1052         return 0;
1053 }
1054
1055 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
1056                           struct extent_buffer *leaf,
1057                           struct btrfs_chunk *chunk)
1058 {
1059         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
1060         struct map_lookup *map;
1061         struct cache_extent *ce;
1062         u64 logical;
1063         u64 length;
1064         u64 devid;
1065         u64 super_offset_diff = 0;
1066         u8 uuid[BTRFS_UUID_SIZE];
1067         int num_stripes;
1068         int ret;
1069         int i;
1070
1071         logical = key->offset;
1072         length = btrfs_chunk_length(leaf, chunk);
1073
1074         if (logical < BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE) {
1075                 super_offset_diff = BTRFS_SUPER_INFO_OFFSET +
1076                         BTRFS_SUPER_INFO_SIZE - logical;
1077                 logical = BTRFS_SUPER_INFO_OFFSET + BTRFS_SUPER_INFO_SIZE;
1078         }
1079
1080         ce = find_first_cache_extent(&map_tree->cache_tree, logical);
1081
1082         /* already mapped? */
1083         if (ce && ce->start <= logical && ce->start + ce->size > logical) {
1084                 return 0;
1085         }
1086
1087         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
1088         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
1089         if (!map)
1090                 return -ENOMEM;
1091
1092         map->ce.start = logical;
1093         map->ce.size = length - super_offset_diff;
1094         map->num_stripes = num_stripes;
1095         map->io_width = btrfs_chunk_io_width(leaf, chunk);
1096         map->io_align = btrfs_chunk_io_align(leaf, chunk);
1097         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
1098         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
1099         map->type = btrfs_chunk_type(leaf, chunk);
1100         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
1101
1102         for (i = 0; i < num_stripes; i++) {
1103                 map->stripes[i].physical =
1104                         btrfs_stripe_offset_nr(leaf, chunk, i) +
1105                                 super_offset_diff;
1106                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
1107                 read_extent_buffer(leaf, uuid, (unsigned long)
1108                                    btrfs_stripe_dev_uuid_nr(chunk, i),
1109                                    BTRFS_UUID_SIZE);
1110                 map->stripes[i].dev = btrfs_find_device(root, devid, uuid);
1111                 if (!map->stripes[i].dev) {
1112                         kfree(map);
1113                         return -EIO;
1114                 }
1115
1116         }
1117         ret = insert_existing_cache_extent(&map_tree->cache_tree, &map->ce);
1118         BUG_ON(ret);
1119
1120         return 0;
1121 }
1122
1123 static int fill_device_from_item(struct extent_buffer *leaf,
1124                                  struct btrfs_dev_item *dev_item,
1125                                  struct btrfs_device *device)
1126 {
1127         unsigned long ptr;
1128
1129         device->devid = btrfs_device_id(leaf, dev_item);
1130         device->total_bytes = btrfs_device_total_bytes(leaf, dev_item);
1131         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
1132         device->type = btrfs_device_type(leaf, dev_item);
1133         device->io_align = btrfs_device_io_align(leaf, dev_item);
1134         device->io_width = btrfs_device_io_width(leaf, dev_item);
1135         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
1136
1137         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1138         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1139
1140         return 0;
1141 }
1142
1143 static int read_one_dev(struct btrfs_root *root,
1144                         struct extent_buffer *leaf,
1145                         struct btrfs_dev_item *dev_item)
1146 {
1147         struct btrfs_device *device;
1148         u64 devid;
1149         int ret = 0;
1150         u8 dev_uuid[BTRFS_UUID_SIZE];
1151
1152         devid = btrfs_device_id(leaf, dev_item);
1153         read_extent_buffer(leaf, dev_uuid,
1154                            (unsigned long)btrfs_device_uuid(dev_item),
1155                            BTRFS_UUID_SIZE);
1156         device = btrfs_find_device(root, devid, dev_uuid);
1157         if (!device) {
1158                 printk("warning devid %llu not found already\n",
1159                         (unsigned long long)devid);
1160                 device = kmalloc(sizeof(*device), GFP_NOFS);
1161                 if (!device)
1162                         return -ENOMEM;
1163                 device->total_ios = 0;
1164                 list_add(&device->dev_list,
1165                          &root->fs_info->fs_devices->devices);
1166         }
1167
1168         fill_device_from_item(leaf, dev_item, device);
1169         device->dev_root = root->fs_info->dev_root;
1170         return ret;
1171 }
1172
1173 int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf)
1174 {
1175         struct btrfs_dev_item *dev_item;
1176
1177         dev_item = (struct btrfs_dev_item *)offsetof(struct btrfs_super_block,
1178                                                      dev_item);
1179         return read_one_dev(root, buf, dev_item);
1180 }
1181
1182 int btrfs_read_sys_array(struct btrfs_root *root)
1183 {
1184         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
1185         struct extent_buffer *sb = root->fs_info->sb_buffer;
1186         struct btrfs_disk_key *disk_key;
1187         struct btrfs_chunk *chunk;
1188         struct btrfs_key key;
1189         u32 num_stripes;
1190         u32 array_size;
1191         u32 len = 0;
1192         u8 *ptr;
1193         unsigned long sb_ptr;
1194         u32 cur;
1195         int ret;
1196
1197         array_size = btrfs_super_sys_array_size(super_copy);
1198
1199         /*
1200          * we do this loop twice, once for the device items and
1201          * once for all of the chunks.  This way there are device
1202          * structs filled in for every chunk
1203          */
1204         ptr = super_copy->sys_chunk_array;
1205         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
1206         cur = 0;
1207
1208         while (cur < array_size) {
1209                 disk_key = (struct btrfs_disk_key *)ptr;
1210                 btrfs_disk_key_to_cpu(&key, disk_key);
1211
1212                 len = sizeof(*disk_key);
1213                 ptr += len;
1214                 sb_ptr += len;
1215                 cur += len;
1216
1217                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1218                         chunk = (struct btrfs_chunk *)sb_ptr;
1219                         ret = read_one_chunk(root, &key, sb, chunk);
1220                         BUG_ON(ret);
1221                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
1222                         len = btrfs_chunk_item_size(num_stripes);
1223                 } else {
1224                         BUG();
1225                 }
1226                 ptr += len;
1227                 sb_ptr += len;
1228                 cur += len;
1229         }
1230         return 0;
1231 }
1232
1233 int btrfs_read_chunk_tree(struct btrfs_root *root)
1234 {
1235         struct btrfs_path *path;
1236         struct extent_buffer *leaf;
1237         struct btrfs_key key;
1238         struct btrfs_key found_key;
1239         int ret;
1240         int slot;
1241
1242         root = root->fs_info->chunk_root;
1243
1244         path = btrfs_alloc_path();
1245         if (!path)
1246                 return -ENOMEM;
1247
1248         /* first we search for all of the device items, and then we
1249          * read in all of the chunk items.  This way we can create chunk
1250          * mappings that reference all of the devices that are afound
1251          */
1252         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1253         key.offset = 0;
1254         key.type = 0;
1255 again:
1256         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1257         while(1) {
1258                 leaf = path->nodes[0];
1259                 slot = path->slots[0];
1260                 if (slot >= btrfs_header_nritems(leaf)) {
1261                         ret = btrfs_next_leaf(root, path);
1262                         if (ret == 0)
1263                                 continue;
1264                         if (ret < 0)
1265                                 goto error;
1266                         break;
1267                 }
1268                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1269                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
1270                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
1271                                 break;
1272                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
1273                                 struct btrfs_dev_item *dev_item;
1274                                 dev_item = btrfs_item_ptr(leaf, slot,
1275                                                   struct btrfs_dev_item);
1276                                 ret = read_one_dev(root, leaf, dev_item);
1277                                 BUG_ON(ret);
1278                         }
1279                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
1280                         struct btrfs_chunk *chunk;
1281                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
1282                         ret = read_one_chunk(root, &found_key, leaf, chunk);
1283                 }
1284                 path->slots[0]++;
1285         }
1286         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
1287                 key.objectid = 0;
1288                 btrfs_release_path(root, path);
1289                 goto again;
1290         }
1291
1292         btrfs_free_path(path);
1293         ret = 0;
1294 error:
1295         return ret;
1296 }
1297
1298 struct list_head *btrfs_scanned_uuids(void)
1299 {
1300         return &fs_uuids;
1301 }