fs/btrfs/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 #include <linux/sched.h>
  19 #include <linux/bio.h>
  20 #include <linux/buffer_head.h>
  21 #include <linux/blkdev.h>
  22 #include <asm/div64.h>
  23 #include "ctree.h"
  24 #include "extent_map.h"
  25 #include "disk-io.h"
  26 #include "transaction.h"
  27 #include "print-tree.h"
  28 #include "volumes.h"
  29
  30 struct map_lookup {
  31         u64 type;
  32         int io_align;
  33         int io_width;
  34         int stripe_len;
  35         int sector_size;
  36         int num_stripes;
  37         int sub_stripes;
  38         struct btrfs_bio_stripe stripes[];
  39 };
  40
  41 #define map_lookup_size(n) (sizeof(struct map_lookup) + \
  42                             (sizeof(struct btrfs_bio_stripe) * (n)))
  43
  44 static DEFINE_MUTEX(uuid_mutex);
  45 static LIST_HEAD(fs_uuids);
  46
  47 int btrfs_cleanup_fs_uuids(void)
  48 {
  49         struct btrfs_fs_devices *fs_devices;
  50         struct list_head *uuid_cur;
  51         struct list_head *devices_cur;
  52         struct btrfs_device *dev;
  53
  54         list_for_each(uuid_cur, &fs_uuids) {
  55                 fs_devices = list_entry(uuid_cur, struct btrfs_fs_devices,
  56                                         list);
  57                 while(!list_empty(&fs_devices->devices)) {
  58                         devices_cur = fs_devices->devices.next;
  59                         dev = list_entry(devices_cur, struct btrfs_device,
  60                                          dev_list);
  61                         if (dev->bdev) {
  62                                 close_bdev_excl(dev->bdev);
  63                         }
  64                         list_del(&dev->dev_list);
  65                         kfree(dev);
  66                 }
  67         }
  68         return 0;
  69 }
  70
  71 static struct btrfs_device *__find_device(struct list_head *head, u64 devid,
  72                                           u8 *uuid)
  73 {
  74         struct btrfs_device *dev;
  75         struct list_head *cur;
  76
  77         list_for_each(cur, head) {
  78                 dev = list_entry(cur, struct btrfs_device, dev_list);
  79                 if (dev->devid == devid &&
  80                     !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE)) {
  81                         return dev;
  82                 }
  83         }
  84         return NULL;
  85 }
  86
  87 static struct btrfs_fs_devices *find_fsid(u8 *fsid)
  88 {
  89         struct list_head *cur;
  90         struct btrfs_fs_devices *fs_devices;
  91
  92         list_for_each(cur, &fs_uuids) {
  93                 fs_devices = list_entry(cur, struct btrfs_fs_devices, list);
  94                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
  95                         return fs_devices;
  96         }
  97         return NULL;
  98 }
  99
 100 static int device_list_add(const char *path,
 101                            struct btrfs_super_block *disk_super,
 102                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 103 {
 104         struct btrfs_device *device;
 105         struct btrfs_fs_devices *fs_devices;
 106         u64 found_transid = btrfs_super_generation(disk_super);
 107
 108         fs_devices = find_fsid(disk_super->fsid);
 109         if (!fs_devices) {
 110                 fs_devices = kmalloc(sizeof(*fs_devices), GFP_NOFS);
 111                 if (!fs_devices)
 112                         return -ENOMEM;
 113                 INIT_LIST_HEAD(&fs_devices->devices);
 114                 list_add(&fs_devices->list, &fs_uuids);
 115                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
 116                 fs_devices->latest_devid = devid;
 117                 fs_devices->latest_trans = found_transid;
 118                 fs_devices->lowest_devid = (u64)-1;
 119                 fs_devices->num_devices = 0;
 120                 device = NULL;
 121         } else {
 122                 device = __find_device(&fs_devices->devices, devid,
 123                                        disk_super->dev_item.uuid);
 124         }
 125         if (!device) {
 126                 device = kzalloc(sizeof(*device), GFP_NOFS);
 127                 if (!device) {
 128                         /* we can safely leave the fs_devices entry around */
 129                         return -ENOMEM;
 130                 }
 131                 device->devid = devid;
 132                 memcpy(device->uuid, disk_super->dev_item.uuid,
 133                        BTRFS_UUID_SIZE);
 134                 device->barriers = 1;
 135                 spin_lock_init(&device->io_lock);
 136                 device->name = kstrdup(path, GFP_NOFS);
 137                 if (!device->name) {
 138                         kfree(device);
 139                         return -ENOMEM;
 140                 }
 141                 list_add(&device->dev_list, &fs_devices->devices);
 142                 fs_devices->num_devices++;
 143         }
 144
 145         if (found_transid > fs_devices->latest_trans) {
 146                 fs_devices->latest_devid = devid;
 147                 fs_devices->latest_trans = found_transid;
 148         }
 149         if (fs_devices->lowest_devid > devid) {
 150                 fs_devices->lowest_devid = devid;
 151         }
 152         *fs_devices_ret = fs_devices;
 153         return 0;
 154 }
 155
 156 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 157 {
 158         struct list_head *head = &fs_devices->devices;
 159         struct list_head *cur;
 160         struct btrfs_device *device;
 161
 162         mutex_lock(&uuid_mutex);
 163         list_for_each(cur, head) {
 164                 device = list_entry(cur, struct btrfs_device, dev_list);
 165                 if (device->bdev) {
 166                         close_bdev_excl(device->bdev);
 167                 }
 168                 device->bdev = NULL;
 169         }
 170         mutex_unlock(&uuid_mutex);
 171         return 0;
 172 }
 173
 174 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 175                        int flags, void *holder)
 176 {
 177         struct block_device *bdev;
 178         struct list_head *head = &fs_devices->devices;
 179         struct list_head *cur;
 180         struct btrfs_device *device;
 181         int ret;
 182
 183         mutex_lock(&uuid_mutex);
 184         list_for_each(cur, head) {
 185                 device = list_entry(cur, struct btrfs_device, dev_list);
 186                 bdev = open_bdev_excl(device->name, flags, holder);
 187
 188                 if (IS_ERR(bdev)) {
 189                         printk("open %s failed\n", device->name);
 190                         ret = PTR_ERR(bdev);
 191                         goto fail;
 192                 }
 193                 if (device->devid == fs_devices->latest_devid)
 194                         fs_devices->latest_bdev = bdev;
 195                 if (device->devid == fs_devices->lowest_devid) {
 196                         fs_devices->lowest_bdev = bdev;
 197                 }
 198                 device->bdev = bdev;
 199         }
 200         mutex_unlock(&uuid_mutex);
 201         return 0;
 202 fail:
 203         mutex_unlock(&uuid_mutex);
 204         btrfs_close_devices(fs_devices);
 205         return ret;
 206 }
 207
 208 int btrfs_scan_one_device(const char *path, int flags, void *holder,
 209                           struct btrfs_fs_devices **fs_devices_ret)
 210 {
 211         struct btrfs_super_block *disk_super;
 212         struct block_device *bdev;
 213         struct buffer_head *bh;
 214         int ret;
 215         u64 devid;
 216         u64 transid;
 217
 218         mutex_lock(&uuid_mutex);
 219
 220         bdev = open_bdev_excl(path, flags, holder);
 221
 222         if (IS_ERR(bdev)) {
 223                 ret = PTR_ERR(bdev);
 224                 goto error;
 225         }
 226
 227         ret = set_blocksize(bdev, 4096);
 228         if (ret)
 229                 goto error_close;
 230         bh = __bread(bdev, BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
 231         if (!bh) {
 232                 ret = -EIO;
 233                 goto error_close;
 234         }
 235         disk_super = (struct btrfs_super_block *)bh->b_data;
 236         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
 237             sizeof(disk_super->magic))) {
 238                 ret = -EINVAL;
 239                 goto error_brelse;
 240         }
 241         devid = le64_to_cpu(disk_super->dev_item.devid);
 242         transid = btrfs_super_generation(disk_super);
 243         if (disk_super->label[0])
 244                 printk("device label %s ", disk_super->label);
 245         else {
 246                 /* FIXME, make a readl uuid parser */
 247                 printk("device fsid %llx-%llx ",
 248                        *(unsigned long long *)disk_super->fsid,
 249                        *(unsigned long long *)(disk_super->fsid + 8));
 250         }
 251         printk("devid %Lu transid %Lu %s\n", devid, transid, path);
 252         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 253
 254 error_brelse:
 255         brelse(bh);
 256 error_close:
 257         close_bdev_excl(bdev);
 258 error:
 259         mutex_unlock(&uuid_mutex);
 260         return ret;
 261 }
 262
 263 /*
 264  * this uses a pretty simple search, the expectation is that it is
 265  * called very infrequently and that a given device has a small number
 266  * of extents
 267  */
 268 static int find_free_dev_extent(struct btrfs_trans_handle *trans,
 269                                 struct btrfs_device *device,
 270                                 struct btrfs_path *path,
 271                                 u64 num_bytes, u64 *start)
 272 {
 273         struct btrfs_key key;
 274         struct btrfs_root *root = device->dev_root;
 275         struct btrfs_dev_extent *dev_extent = NULL;
 276         u64 hole_size = 0;
 277         u64 last_byte = 0;
 278         u64 search_start = 0;
 279         u64 search_end = device->total_bytes;
 280         int ret;
 281         int slot = 0;
 282         int start_found;
 283         struct extent_buffer *l;
 284
 285         start_found = 0;
 286         path->reada = 2;
 287
 288         /* FIXME use last free of some kind */
 289
 290         /* we don't want to overwrite the superblock on the drive,
 291          * so we make sure to start at an offset of at least 1MB
 292          */
 293         search_start = max((u64)1024 * 1024, search_start);
 294         key.objectid = device->devid;
 295         key.offset = search_start;
 296         key.type = BTRFS_DEV_EXTENT_KEY;
 297         ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
 298         if (ret < 0)
 299                 goto error;
 300         ret = btrfs_previous_item(root, path, 0, key.type);
 301         if (ret < 0)
 302                 goto error;
 303         l = path->nodes[0];
 304         btrfs_item_key_to_cpu(l, &key, path->slots[0]);
 305         while (1) {
 306                 l = path->nodes[0];
 307                 slot = path->slots[0];
 308                 if (slot >= btrfs_header_nritems(l)) {
 309                         ret = btrfs_next_leaf(root, path);
 310                         if (ret == 0)
 311                                 continue;
 312                         if (ret < 0)
 313                                 goto error;
 314 no_more_items:
 315                         if (!start_found) {
 316                                 if (search_start >= search_end) {
 317                                         ret = -ENOSPC;
 318                                         goto error;
 319                                 }
 320                                 *start = search_start;
 321                                 start_found = 1;
 322                                 goto check_pending;
 323                         }
 324                         *start = last_byte > search_start ?
 325                                 last_byte : search_start;
 326                         if (search_end <= *start) {
 327                                 ret = -ENOSPC;
 328                                 goto error;
 329                         }
 330                         goto check_pending;
 331                 }
 332                 btrfs_item_key_to_cpu(l, &key, slot);
 333
 334                 if (key.objectid < device->devid)
 335                         goto next;
 336
 337                 if (key.objectid > device->devid)
 338                         goto no_more_items;
 339
 340                 if (key.offset >= search_start && key.offset > last_byte &&
 341                     start_found) {
 342                         if (last_byte < search_start)
 343                                 last_byte = search_start;
 344                         hole_size = key.offset - last_byte;
 345                         if (key.offset > last_byte &&
 346                             hole_size >= num_bytes) {
 347                                 *start = last_byte;
 348                                 goto check_pending;
 349                         }
 350                 }
 351                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY) {
 352                         goto next;
 353                 }
 354
 355                 start_found = 1;
 356                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 357                 last_byte = key.offset + btrfs_dev_extent_length(l, dev_extent);
 358 next:
 359                 path->slots[0]++;
 360                 cond_resched();
 361         }
 362 check_pending:
 363         /* we have to make sure we didn't find an extent that has already
 364          * been allocated by the map tree or the original allocation
 365          */
 366         btrfs_release_path(root, path);
 367         BUG_ON(*start < search_start);
 368
 369         if (*start + num_bytes > search_end) {
 370                 ret = -ENOSPC;
 371                 goto error;
 372         }
 373         /* check for pending inserts here */
 374         return 0;
 375
 376 error:
 377         btrfs_release_path(root, path);
 378         return ret;
 379 }
 380
 381 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
 382                            struct btrfs_device *device,
 383                            u64 chunk_tree, u64 chunk_objectid,
 384                            u64 chunk_offset,
 385                            u64 num_bytes, u64 *start)
 386 {
 387         int ret;
 388         struct btrfs_path *path;
 389         struct btrfs_root *root = device->dev_root;
 390         struct btrfs_dev_extent *extent;
 391         struct extent_buffer *leaf;
 392         struct btrfs_key key;
 393
 394         path = btrfs_alloc_path();
 395         if (!path)
 396                 return -ENOMEM;
 397
 398         ret = find_free_dev_extent(trans, device, path, num_bytes, start);
 399         if (ret) {
 400                 goto err;
 401         }
 402
 403         key.objectid = device->devid;
 404         key.offset = *start;
 405         key.type = BTRFS_DEV_EXTENT_KEY;
 406         ret = btrfs_insert_empty_item(trans, root, path, &key,
 407                                       sizeof(*extent));
 408         BUG_ON(ret);
 409
 410         leaf = path->nodes[0];
 411         extent = btrfs_item_ptr(leaf, path->slots[0],
 412                                 struct btrfs_dev_extent);
 413         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
 414         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
 415         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
 416
 417         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
 418                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
 419                     BTRFS_UUID_SIZE);
 420
 421         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
 422         btrfs_mark_buffer_dirty(leaf);
 423 err:
 424         btrfs_free_path(path);
 425         return ret;
 426 }
 427
 428 static int find_next_chunk(struct btrfs_root *root, u64 objectid, u64 *offset)
 429 {
 430         struct btrfs_path *path;
 431         int ret;
 432         struct btrfs_key key;
 433         struct btrfs_chunk *chunk;
 434         struct btrfs_key found_key;
 435
 436         path = btrfs_alloc_path();
 437         BUG_ON(!path);
 438
 439         key.objectid = objectid;
 440         key.offset = (u64)-1;
 441         key.type = BTRFS_CHUNK_ITEM_KEY;
 442
 443         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 444         if (ret < 0)
 445                 goto error;
 446
 447         BUG_ON(ret == 0);
 448
 449         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
 450         if (ret) {
 451                 *offset = 0;
 452         } else {
 453                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 454                                       path->slots[0]);
 455                 if (found_key.objectid != objectid)
 456                         *offset = 0;
 457                 else {
 458                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
 459                                                struct btrfs_chunk);
 460                         *offset = found_key.offset +
 461                                 btrfs_chunk_length(path->nodes[0], chunk);
 462                 }
 463         }
 464         ret = 0;
 465 error:
 466         btrfs_free_path(path);
 467         return ret;
 468 }
 469
 470 static int find_next_devid(struct btrfs_root *root, struct btrfs_path *path,
 471                            u64 *objectid)
 472 {
 473         int ret;
 474         struct btrfs_key key;
 475         struct btrfs_key found_key;
 476
 477         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
 478         key.type = BTRFS_DEV_ITEM_KEY;
 479         key.offset = (u64)-1;
 480
 481         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 482         if (ret < 0)
 483                 goto error;
 484
 485         BUG_ON(ret == 0);
 486
 487         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
 488                                   BTRFS_DEV_ITEM_KEY);
 489         if (ret) {
 490                 *objectid = 1;
 491         } else {
 492                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 493                                       path->slots[0]);
 494                 *objectid = found_key.offset + 1;
 495         }
 496         ret = 0;
 497 error:
 498         btrfs_release_path(root, path);
 499         return ret;
 500 }
 501
 502 /*
 503  * the device information is stored in the chunk root
 504  * the btrfs_device struct should be fully filled in
 505  */
 506 int btrfs_add_device(struct btrfs_trans_handle *trans,
 507                      struct btrfs_root *root,
 508                      struct btrfs_device *device)
 509 {
 510         int ret;
 511         struct btrfs_path *path;
 512         struct btrfs_dev_item *dev_item;
 513         struct extent_buffer *leaf;
 514         struct btrfs_key key;
 515         unsigned long ptr;
 516         u64 free_devid;
 517
 518         root = root->fs_info->chunk_root;
 519
 520         path = btrfs_alloc_path();
 521         if (!path)
 522                 return -ENOMEM;
 523
 524         ret = find_next_devid(root, path, &free_devid);
 525         if (ret)
 526                 goto out;
 527
 528         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
 529         key.type = BTRFS_DEV_ITEM_KEY;
 530         key.offset = free_devid;
 531
 532         ret = btrfs_insert_empty_item(trans, root, path, &key,
 533                                       sizeof(*dev_item));
 534         if (ret)
 535                 goto out;
 536
 537         leaf = path->nodes[0];
 538         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
 539
 540         device->devid = free_devid;
 541         btrfs_set_device_id(leaf, dev_item, device->devid);
 542         btrfs_set_device_type(leaf, dev_item, device->type);
 543         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
 544         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
 545         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
 546         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
 547         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
 548         btrfs_set_device_group(leaf, dev_item, 0);
 549         btrfs_set_device_seek_speed(leaf, dev_item, 0);
 550         btrfs_set_device_bandwidth(leaf, dev_item, 0);
 551
 552         ptr = (unsigned long)btrfs_device_uuid(dev_item);
 553         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
 554         btrfs_mark_buffer_dirty(leaf);
 555         ret = 0;
 556
 557 out:
 558         btrfs_free_path(path);
 559         return ret;
 560 }
 561 int btrfs_update_device(struct btrfs_trans_handle *trans,
 562                         struct btrfs_device *device)
 563 {
 564         int ret;
 565         struct btrfs_path *path;
 566         struct btrfs_root *root;
 567         struct btrfs_dev_item *dev_item;
 568         struct extent_buffer *leaf;
 569         struct btrfs_key key;
 570
 571         root = device->dev_root->fs_info->chunk_root;
 572
 573         path = btrfs_alloc_path();
 574         if (!path)
 575                 return -ENOMEM;
 576
 577         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
 578         key.type = BTRFS_DEV_ITEM_KEY;
 579         key.offset = device->devid;
 580
 581         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
 582         if (ret < 0)
 583                 goto out;
 584
 585         if (ret > 0) {
 586                 ret = -ENOENT;
 587                 goto out;
 588         }
 589
 590         leaf = path->nodes[0];
 591         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
 592
 593         btrfs_set_device_id(leaf, dev_item, device->devid);
 594         btrfs_set_device_type(leaf, dev_item, device->type);
 595         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
 596         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
 597         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
 598         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
 599         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
 600         btrfs_mark_buffer_dirty(leaf);
 601
 602 out:
 603         btrfs_free_path(path);
 604         return ret;
 605 }
 606
 607 int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
 608                            struct btrfs_root *root,
 609                            struct btrfs_key *key,
 610                            struct btrfs_chunk *chunk, int item_size)
 611 {
 612         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
 613         struct btrfs_disk_key disk_key;
 614         u32 array_size;
 615         u8 *ptr;
 616
 617         array_size = btrfs_super_sys_array_size(super_copy);
 618         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
 619                 return -EFBIG;
 620
 621         ptr = super_copy->sys_chunk_array + array_size;
 622         btrfs_cpu_key_to_disk(&disk_key, key);
 623         memcpy(ptr, &disk_key, sizeof(disk_key));
 624         ptr += sizeof(disk_key);
 625         memcpy(ptr, chunk, item_size);
 626         item_size += sizeof(disk_key);
 627         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
 628         return 0;
 629 }
 630
 631 static u64 div_factor(u64 num, int factor)
 632 {
 633         if (factor == 10)
 634                 return num;
 635         num *= factor;
 636         do_div(num, 10);
 637         return num;
 638 }
 639
 640 static u64 chunk_bytes_by_type(u64 type, u64 calc_size, int num_stripes,
 641                                int sub_stripes)
 642 {
 643         if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
 644                 return calc_size;
 645         else if (type & BTRFS_BLOCK_GROUP_RAID10)
 646                 return calc_size * (num_stripes / sub_stripes);
 647         else
 648                 return calc_size * num_stripes;
 649 }
 650
 651
 652 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 653                       struct btrfs_root *extent_root, u64 *start,
 654                       u64 *num_bytes, u64 type)
 655 {
 656         u64 dev_offset;
 657         struct btrfs_fs_info *info = extent_root->fs_info;
 658         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
 659         struct btrfs_stripe *stripes;
 660         struct btrfs_device *device = NULL;
 661         struct btrfs_chunk *chunk;
 662         struct list_head private_devs;
 663         struct list_head *dev_list = &extent_root->fs_info->fs_devices->devices;
 664         struct list_head *cur;
 665         struct extent_map_tree *em_tree;
 666         struct map_lookup *map;
 667         struct extent_map *em;
 668         int min_stripe_size = 1 * 1024 * 1024;
 669         u64 physical;
 670         u64 calc_size = 1024 * 1024 * 1024;
 671         u64 max_chunk_size = calc_size;
 672         u64 min_free;
 673         u64 avail;
 674         u64 max_avail = 0;
 675         u64 percent_max;
 676         int num_stripes = 1;
 677         int min_stripes = 1;
 678         int sub_stripes = 0;
 679         int looped = 0;
 680         int ret;
 681         int index;
 682         int stripe_len = 64 * 1024;
 683         struct btrfs_key key;
 684
 685         if (list_empty(dev_list))
 686                 return -ENOSPC;
 687
 688         if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
 689                 num_stripes = btrfs_super_num_devices(&info->super_copy);
 690                 min_stripes = 2;
 691         }
 692         if (type & (BTRFS_BLOCK_GROUP_DUP)) {
 693                 num_stripes = 2;
 694                 min_stripes = 2;
 695         }
 696         if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
 697                 num_stripes = min_t(u64, 2,
 698                                   btrfs_super_num_devices(&info->super_copy));
 699                 if (num_stripes < 2)
 700                         return -ENOSPC;
 701                 min_stripes = 2;
 702         }
 703         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
 704                 num_stripes = btrfs_super_num_devices(&info->super_copy);
 705                 if (num_stripes < 4)
 706                         return -ENOSPC;
 707                 num_stripes &= ~(u32)1;
 708                 sub_stripes = 2;
 709                 min_stripes = 4;
 710         }
 711
 712         if (type & BTRFS_BLOCK_GROUP_DATA) {
 713                 max_chunk_size = 10 * calc_size;
 714                 min_stripe_size = 64 * 1024 * 1024;
 715         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
 716                 max_chunk_size = 4 * calc_size;
 717                 min_stripe_size = 32 * 1024 * 1024;
 718         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
 719                 calc_size = 8 * 1024 * 1024;
 720                 max_chunk_size = calc_size * 2;
 721                 min_stripe_size = 1 * 1024 * 1024;
 722         }
 723
 724         /* we don't want a chunk larger than 10% of the FS */
 725         percent_max = div_factor(btrfs_super_total_bytes(&info->super_copy), 1);
 726         max_chunk_size = min(percent_max, max_chunk_size);
 727
 728 again:
 729         if (calc_size * num_stripes > max_chunk_size) {
 730                 calc_size = max_chunk_size;
 731                 do_div(calc_size, num_stripes);
 732                 do_div(calc_size, stripe_len);
 733                 calc_size *= stripe_len;
 734         }
 735         /* we don't want tiny stripes */
 736         calc_size = max_t(u64, min_stripe_size, calc_size);
 737
 738         do_div(calc_size, stripe_len);
 739         calc_size *= stripe_len;
 740
 741         INIT_LIST_HEAD(&private_devs);
 742         cur = dev_list->next;
 743         index = 0;
 744
 745         if (type & BTRFS_BLOCK_GROUP_DUP)
 746                 min_free = calc_size * 2;
 747         else
 748                 min_free = calc_size;
 749
 750         /* we add 1MB because we never use the first 1MB of the device */
 751         min_free += 1024 * 1024;
 752
 753         /* build a private list of devices we will allocate from */
 754         while(index < num_stripes) {
 755                 device = list_entry(cur, struct btrfs_device, dev_list);
 756
 757                 avail = device->total_bytes - device->bytes_used;
 758                 cur = cur->next;
 759                 if (avail >= min_free) {
 760                         list_move_tail(&device->dev_list, &private_devs);
 761                         index++;
 762                         if (type & BTRFS_BLOCK_GROUP_DUP)
 763                                 index++;
 764                 } else if (avail > max_avail)
 765                         max_avail = avail;
 766                 if (cur == dev_list)
 767                         break;
 768         }
 769         if (index < num_stripes) {
 770                 list_splice(&private_devs, dev_list);
 771                 if (index >= min_stripes) {
 772                         num_stripes = index;
 773                         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
 774                                 num_stripes /= sub_stripes;
 775                                 num_stripes *= sub_stripes;
 776                         }
 777                         looped = 1;
 778                         goto again;
 779                 }
 780                 if (!looped && max_avail > 0) {
 781                         looped = 1;
 782                         calc_size = max_avail;
 783                         goto again;
 784                 }
 785                 return -ENOSPC;
 786         }
 787         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
 788         key.type = BTRFS_CHUNK_ITEM_KEY;
 789         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
 790                               &key.offset);
 791         if (ret)
 792                 return ret;
 793
 794         chunk = kmalloc(btrfs_chunk_item_size(num_stripes), GFP_NOFS);
 795         if (!chunk)
 796                 return -ENOMEM;
 797
 798         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
 799         if (!map) {
 800                 kfree(chunk);
 801                 return -ENOMEM;
 802         }
 803
 804         stripes = &chunk->stripe;
 805         *num_bytes = chunk_bytes_by_type(type, calc_size,
 806                                          num_stripes, sub_stripes);
 807
 808
 809         index = 0;
 810 printk("new chunk type %Lu start %Lu size %Lu\n", type, key.offset, *num_bytes);
 811         while(index < num_stripes) {
 812                 struct btrfs_stripe *stripe;
 813                 BUG_ON(list_empty(&private_devs));
 814                 cur = private_devs.next;
 815                 device = list_entry(cur, struct btrfs_device, dev_list);
 816
 817                 /* loop over this device again if we're doing a dup group */
 818                 if (!(type & BTRFS_BLOCK_GROUP_DUP) ||
 819                     (index == num_stripes - 1))
 820                         list_move_tail(&device->dev_list, dev_list);
 821
 822                 ret = btrfs_alloc_dev_extent(trans, device,
 823                              info->chunk_root->root_key.objectid,
 824                              BTRFS_FIRST_CHUNK_TREE_OBJECTID, key.offset,
 825                              calc_size, &dev_offset);
 826                 BUG_ON(ret);
 827 printk("alloc chunk start %Lu size %Lu from dev %Lu type %Lu\n", key.offset, calc_size, device->devid, type);
 828                 device->bytes_used += calc_size;
 829                 ret = btrfs_update_device(trans, device);
 830                 BUG_ON(ret);
 831
 832                 map->stripes[index].dev = device;
 833                 map->stripes[index].physical = dev_offset;
 834                 stripe = stripes + index;
 835                 btrfs_set_stack_stripe_devid(stripe, device->devid);
 836                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
 837                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
 838                 physical = dev_offset;
 839                 index++;
 840         }
 841         BUG_ON(!list_empty(&private_devs));
 842
 843         /* key was set above */
 844         btrfs_set_stack_chunk_length(chunk, *num_bytes);
 845         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
 846         btrfs_set_stack_chunk_stripe_len(chunk, stripe_len);
 847         btrfs_set_stack_chunk_type(chunk, type);
 848         btrfs_set_stack_chunk_num_stripes(chunk, num_stripes);
 849         btrfs_set_stack_chunk_io_align(chunk, stripe_len);
 850         btrfs_set_stack_chunk_io_width(chunk, stripe_len);
 851         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
 852         btrfs_set_stack_chunk_sub_stripes(chunk, sub_stripes);
 853         map->sector_size = extent_root->sectorsize;
 854         map->stripe_len = stripe_len;
 855         map->io_align = stripe_len;
 856         map->io_width = stripe_len;
 857         map->type = type;
 858         map->num_stripes = num_stripes;
 859         map->sub_stripes = sub_stripes;
 860
 861         ret = btrfs_insert_item(trans, chunk_root, &key, chunk,
 862                                 btrfs_chunk_item_size(num_stripes));
 863         BUG_ON(ret);
 864         *start = key.offset;;
 865
 866         em = alloc_extent_map(GFP_NOFS);
 867         if (!em)
 868                 return -ENOMEM;
 869         em->bdev = (struct block_device *)map;
 870         em->start = key.offset;
 871         em->len = *num_bytes;
 872         em->block_start = 0;
 873
 874         kfree(chunk);
 875
 876         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
 877         spin_lock(&em_tree->lock);
 878         ret = add_extent_mapping(em_tree, em);
 879         spin_unlock(&em_tree->lock);
 880         BUG_ON(ret);
 881         free_extent_map(em);
 882         return ret;
 883 }
 884
 885 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
 886 {
 887         extent_map_tree_init(&tree->map_tree, GFP_NOFS);
 888 }
 889
 890 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
 891 {
 892         struct extent_map *em;
 893
 894         while(1) {
 895                 spin_lock(&tree->map_tree.lock);
 896                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
 897                 if (em)
 898                         remove_extent_mapping(&tree->map_tree, em);
 899                 spin_unlock(&tree->map_tree.lock);
 900                 if (!em)
 901                         break;
 902                 kfree(em->bdev);
 903                 /* once for us */
 904                 free_extent_map(em);
 905                 /* once for the tree */
 906                 free_extent_map(em);
 907         }
 908 }
 909
 910 int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
 911 {
 912         struct extent_map *em;
 913         struct map_lookup *map;
 914         struct extent_map_tree *em_tree = &map_tree->map_tree;
 915         int ret;
 916
 917         spin_lock(&em_tree->lock);
 918         em = lookup_extent_mapping(em_tree, logical, len);
 919         spin_unlock(&em_tree->lock);
 920         BUG_ON(!em);
 921
 922         BUG_ON(em->start > logical || em->start + em->len < logical);
 923         map = (struct map_lookup *)em->bdev;
 924         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
 925                 ret = map->num_stripes;
 926         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
 927                 ret = map->sub_stripes;
 928         else
 929                 ret = 1;
 930         free_extent_map(em);
 931         return ret;
 932 }
 933
 934 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
 935                              u64 logical, u64 *length,
 936                              struct btrfs_multi_bio **multi_ret,
 937                              int mirror_num, struct page *unplug_page)
 938 {
 939         struct extent_map *em;
 940         struct map_lookup *map;
 941         struct extent_map_tree *em_tree = &map_tree->map_tree;
 942         u64 offset;
 943         u64 stripe_offset;
 944         u64 stripe_nr;
 945         int stripes_allocated = 8;
 946         int stripes_required = 1;
 947         int stripe_index;
 948         int i;
 949         int num_stripes;
 950         struct btrfs_multi_bio *multi = NULL;
 951
 952         if (multi_ret && !(rw & (1 << BIO_RW))) {
 953                 stripes_allocated = 1;
 954         }
 955 again:
 956         if (multi_ret) {
 957                 multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
 958                                 GFP_NOFS);
 959                 if (!multi)
 960                         return -ENOMEM;
 961         }
 962
 963         spin_lock(&em_tree->lock);
 964         em = lookup_extent_mapping(em_tree, logical, *length);
 965         spin_unlock(&em_tree->lock);
 966
 967         if (!em && unplug_page)
 968                 return 0;
 969
 970         if (!em) {
 971                 printk("unable to find logical %Lu\n", logical);
 972                 BUG();
 973         }
 974
 975         BUG_ON(em->start > logical || em->start + em->len < logical);
 976         map = (struct map_lookup *)em->bdev;
 977         offset = logical - em->start;
 978
 979         if (mirror_num > map->num_stripes)
 980                 mirror_num = 0;
 981
 982         /* if our multi bio struct is too small, back off and try again */
 983         if (rw & (1 << BIO_RW)) {
 984                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
 985                                  BTRFS_BLOCK_GROUP_DUP)) {
 986                         stripes_required = map->num_stripes;
 987                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
 988                         stripes_required = map->sub_stripes;
 989                 }
 990         }
 991         if (multi_ret && rw == WRITE &&
 992             stripes_allocated < stripes_required) {
 993                 stripes_allocated = map->num_stripes;
 994                 free_extent_map(em);
 995                 kfree(multi);
 996                 goto again;
 997         }
 998         stripe_nr = offset;
 999         /*
1000          * stripe_nr counts the total number of stripes we have to stride
1001          * to get to this block
1002          */
1003         do_div(stripe_nr, map->stripe_len);
1004
1005         stripe_offset = stripe_nr * map->stripe_len;
1006         BUG_ON(offset < stripe_offset);
1007
1008         /* stripe_offset is the offset of this block in its stripe*/
1009         stripe_offset = offset - stripe_offset;
1010
1011         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
1012                          BTRFS_BLOCK_GROUP_RAID10 |
1013                          BTRFS_BLOCK_GROUP_DUP)) {
1014                 /* we limit the length of each bio to what fits in a stripe */
1015                 *length = min_t(u64, em->len - offset,
1016                               map->stripe_len - stripe_offset);
1017         } else {
1018                 *length = em->len - offset;
1019         }
1020
1021         if (!multi_ret && !unplug_page)
1022                 goto out;
1023
1024         num_stripes = 1;
1025         stripe_index = 0;
1026         if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
1027                 if (unplug_page || (rw & (1 << BIO_RW)))
1028                         num_stripes = map->num_stripes;
1029                 else if (mirror_num) {
1030                         stripe_index = mirror_num - 1;
1031                 } else {
1032                         u64 orig_stripe_nr = stripe_nr;
1033                         stripe_index = do_div(orig_stripe_nr, num_stripes);
1034                 }
1035         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
1036                 if (rw & (1 << BIO_RW))
1037                         num_stripes = map->num_stripes;
1038                 else if (mirror_num)
1039                         stripe_index = mirror_num - 1;
1040         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1041                 int factor = map->num_stripes / map->sub_stripes;
1042
1043                 stripe_index = do_div(stripe_nr, factor);
1044                 stripe_index *= map->sub_stripes;
1045
1046                 if (unplug_page || (rw & (1 << BIO_RW)))
1047                         num_stripes = map->sub_stripes;
1048                 else if (mirror_num)
1049                         stripe_index += mirror_num - 1;
1050                 else {
1051                         u64 orig_stripe_nr = stripe_nr;
1052                         stripe_index += do_div(orig_stripe_nr,
1053                                                map->sub_stripes);
1054                 }
1055         } else {
1056                 /*
1057                  * after this do_div call, stripe_nr is the number of stripes
1058                  * on this device we have to walk to find the data, and
1059                  * stripe_index is the number of our device in the stripe array
1060                  */
1061                 stripe_index = do_div(stripe_nr, map->num_stripes);
1062         }
1063         BUG_ON(stripe_index >= map->num_stripes);
1064
1065         for (i = 0; i < num_stripes; i++) {
1066                 if (unplug_page) {
1067                         struct btrfs_device *device;
1068                         struct backing_dev_info *bdi;
1069
1070                         device = map->stripes[stripe_index].dev;
1071                         bdi = blk_get_backing_dev_info(device->bdev);
1072                         if (bdi->unplug_io_fn) {
1073                                 bdi->unplug_io_fn(bdi, unplug_page);
1074                         }
1075                 } else {
1076                         multi->stripes[i].physical =
1077                                 map->stripes[stripe_index].physical +
1078                                 stripe_offset + stripe_nr * map->stripe_len;
1079                         multi->stripes[i].dev = map->stripes[stripe_index].dev;
1080                 }
1081                 stripe_index++;
1082         }
1083         if (multi_ret) {
1084                 *multi_ret = multi;
1085                 multi->num_stripes = num_stripes;
1086         }
1087 out:
1088         free_extent_map(em);
1089         return 0;
1090 }
1091
1092 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
1093                       u64 logical, u64 *length,
1094                       struct btrfs_multi_bio **multi_ret, int mirror_num)
1095 {
1096         return __btrfs_map_block(map_tree, rw, logical, length, multi_ret,
1097                                  mirror_num, NULL);
1098 }
1099
1100 int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
1101                       u64 logical, struct page *page)
1102 {
1103         u64 length = PAGE_CACHE_SIZE;
1104         return __btrfs_map_block(map_tree, READ, logical, &length,
1105                                  NULL, 0, page);
1106 }
1107
1108
1109 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1110 static void end_bio_multi_stripe(struct bio *bio, int err)
1111 #else
1112 static int end_bio_multi_stripe(struct bio *bio,
1113                                    unsigned int bytes_done, int err)
1114 #endif
1115 {
1116         struct btrfs_multi_bio *multi = bio->bi_private;
1117
1118 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1119         if (bio->bi_size)
1120                 return 1;
1121 #endif
1122         if (err)
1123                 multi->error = err;
1124
1125         if (atomic_dec_and_test(&multi->stripes_pending)) {
1126                 bio->bi_private = multi->private;
1127                 bio->bi_end_io = multi->end_io;
1128
1129                 if (!err && multi->error)
1130                         err = multi->error;
1131                 kfree(multi);
1132
1133 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1134                 bio_endio(bio, bio->bi_size, err);
1135 #else
1136                 bio_endio(bio, err);
1137 #endif
1138         } else {
1139                 bio_put(bio);
1140         }
1141 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1142         return 0;
1143 #endif
1144 }
1145
1146 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
1147                   int mirror_num)
1148 {
1149         struct btrfs_mapping_tree *map_tree;
1150         struct btrfs_device *dev;
1151         struct bio *first_bio = bio;
1152         u64 logical = bio->bi_sector << 9;
1153         u64 length = 0;
1154         u64 map_length;
1155         struct btrfs_multi_bio *multi = NULL;
1156         int ret;
1157         int dev_nr = 0;
1158         int total_devs = 1;
1159
1160         length = bio->bi_size;
1161
1162         map_tree = &root->fs_info->mapping_tree;
1163         map_length = length;
1164
1165         ret = btrfs_map_block(map_tree, rw, logical, &map_length, &multi,
1166                               mirror_num);
1167         BUG_ON(ret);
1168
1169         total_devs = multi->num_stripes;
1170         if (map_length < length) {
1171                 printk("mapping failed logical %Lu bio len %Lu "
1172                        "len %Lu\n", logical, length, map_length);
1173                 BUG();
1174         }
1175         multi->end_io = first_bio->bi_end_io;
1176         multi->private = first_bio->bi_private;
1177         atomic_set(&multi->stripes_pending, multi->num_stripes);
1178
1179         while(dev_nr < total_devs) {
1180                 if (total_devs > 1) {
1181                         if (dev_nr < total_devs - 1) {
1182                                 bio = bio_clone(first_bio, GFP_NOFS);
1183                                 BUG_ON(!bio);
1184                         } else {
1185                                 bio = first_bio;
1186                         }
1187                         bio->bi_private = multi;
1188                         bio->bi_end_io = end_bio_multi_stripe;
1189                 }
1190                 bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
1191                 dev = multi->stripes[dev_nr].dev;
1192                 bio->bi_bdev = dev->bdev;
1193                 spin_lock(&dev->io_lock);
1194                 dev->total_ios++;
1195                 spin_unlock(&dev->io_lock);
1196                 submit_bio(rw, bio);
1197                 dev_nr++;
1198         }
1199         if (total_devs == 1)
1200                 kfree(multi);
1201         return 0;
1202 }
1203
1204 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
1205                                        u8 *uuid)
1206 {
1207         struct list_head *head = &root->fs_info->fs_devices->devices;
1208
1209         return __find_device(head, devid, uuid);
1210 }
1211
1212 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
1213                           struct extent_buffer *leaf,
1214                           struct btrfs_chunk *chunk)
1215 {
1216         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
1217         struct map_lookup *map;
1218         struct extent_map *em;
1219         u64 logical;
1220         u64 length;
1221         u64 devid;
1222         u8 uuid[BTRFS_UUID_SIZE];
1223         int num_stripes;
1224         int ret;
1225         int i;
1226
1227         logical = key->offset;
1228         length = btrfs_chunk_length(leaf, chunk);
1229         spin_lock(&map_tree->map_tree.lock);
1230         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
1231         spin_unlock(&map_tree->map_tree.lock);
1232
1233         /* already mapped? */
1234         if (em && em->start <= logical && em->start + em->len > logical) {
1235                 free_extent_map(em);
1236                 return 0;
1237         } else if (em) {
1238                 free_extent_map(em);
1239         }
1240
1241         map = kzalloc(sizeof(*map), GFP_NOFS);
1242         if (!map)
1243                 return -ENOMEM;
1244
1245         em = alloc_extent_map(GFP_NOFS);
1246         if (!em)
1247                 return -ENOMEM;
1248         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
1249         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
1250         if (!map) {
1251                 free_extent_map(em);
1252                 return -ENOMEM;
1253         }
1254
1255         em->bdev = (struct block_device *)map;
1256         em->start = logical;
1257         em->len = length;
1258         em->block_start = 0;
1259
1260         map->num_stripes = num_stripes;
1261         map->io_width = btrfs_chunk_io_width(leaf, chunk);
1262         map->io_align = btrfs_chunk_io_align(leaf, chunk);
1263         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
1264         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
1265         map->type = btrfs_chunk_type(leaf, chunk);
1266         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
1267         for (i = 0; i < num_stripes; i++) {
1268                 map->stripes[i].physical =
1269                         btrfs_stripe_offset_nr(leaf, chunk, i);
1270                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
1271                 read_extent_buffer(leaf, uuid, (unsigned long)
1272                                    btrfs_stripe_dev_uuid_nr(chunk, i),
1273                                    BTRFS_UUID_SIZE);
1274                 map->stripes[i].dev = btrfs_find_device(root, devid, uuid);
1275                 if (!map->stripes[i].dev) {
1276                         kfree(map);
1277                         free_extent_map(em);
1278                         return -EIO;
1279                 }
1280         }
1281
1282         spin_lock(&map_tree->map_tree.lock);
1283         ret = add_extent_mapping(&map_tree->map_tree, em);
1284         spin_unlock(&map_tree->map_tree.lock);
1285         BUG_ON(ret);
1286         free_extent_map(em);
1287
1288         return 0;
1289 }
1290
1291 static int fill_device_from_item(struct extent_buffer *leaf,
1292                                  struct btrfs_dev_item *dev_item,
1293                                  struct btrfs_device *device)
1294 {
1295         unsigned long ptr;
1296
1297         device->devid = btrfs_device_id(leaf, dev_item);
1298         device->total_bytes = btrfs_device_total_bytes(leaf, dev_item);
1299         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
1300         device->type = btrfs_device_type(leaf, dev_item);
1301         device->io_align = btrfs_device_io_align(leaf, dev_item);
1302         device->io_width = btrfs_device_io_width(leaf, dev_item);
1303         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
1304
1305         ptr = (unsigned long)btrfs_device_uuid(dev_item);
1306         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
1307
1308         return 0;
1309 }
1310
1311 static int read_one_dev(struct btrfs_root *root,
1312                         struct extent_buffer *leaf,
1313                         struct btrfs_dev_item *dev_item)
1314 {
1315         struct btrfs_device *device;
1316         u64 devid;
1317         int ret;
1318         u8 dev_uuid[BTRFS_UUID_SIZE];
1319
1320         devid = btrfs_device_id(leaf, dev_item);
1321         read_extent_buffer(leaf, dev_uuid,
1322                            (unsigned long)btrfs_device_uuid(dev_item),
1323                            BTRFS_UUID_SIZE);
1324         device = btrfs_find_device(root, devid, dev_uuid);
1325         if (!device) {
1326                 printk("warning devid %Lu not found already\n", devid);
1327                 device = kzalloc(sizeof(*device), GFP_NOFS);
1328                 if (!device)
1329                         return -ENOMEM;
1330                 list_add(&device->dev_list,
1331                          &root->fs_info->fs_devices->devices);
1332                 device->barriers = 1;
1333                 spin_lock_init(&device->io_lock);
1334         }
1335
1336         fill_device_from_item(leaf, dev_item, device);
1337         device->dev_root = root->fs_info->dev_root;
1338         ret = 0;
1339 #if 0
1340         ret = btrfs_open_device(device);
1341         if (ret) {
1342                 kfree(device);
1343         }
1344 #endif
1345         return ret;
1346 }
1347
1348 int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf)
1349 {
1350         struct btrfs_dev_item *dev_item;
1351
1352         dev_item = (struct btrfs_dev_item *)offsetof(struct btrfs_super_block,
1353                                                      dev_item);
1354         return read_one_dev(root, buf, dev_item);
1355 }
1356
1357 int btrfs_read_sys_array(struct btrfs_root *root)
1358 {
1359         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
1360         struct extent_buffer *sb = root->fs_info->sb_buffer;
1361         struct btrfs_disk_key *disk_key;
1362         struct btrfs_chunk *chunk;
1363         struct btrfs_key key;
1364         u32 num_stripes;
1365         u32 array_size;
1366         u32 len = 0;
1367         u8 *ptr;
1368         unsigned long sb_ptr;
1369         u32 cur;
1370         int ret;
1371
1372         array_size = btrfs_super_sys_array_size(super_copy);
1373
1374         /*
1375          * we do this loop twice, once for the device items and
1376          * once for all of the chunks.  This way there are device
1377          * structs filled in for every chunk
1378          */
1379         ptr = super_copy->sys_chunk_array;
1380         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
1381         cur = 0;
1382
1383         while (cur < array_size) {
1384                 disk_key = (struct btrfs_disk_key *)ptr;
1385                 btrfs_disk_key_to_cpu(&key, disk_key);
1386
1387                 len = sizeof(*disk_key);
1388                 ptr += len;
1389                 sb_ptr += len;
1390                 cur += len;
1391
1392                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1393                         chunk = (struct btrfs_chunk *)sb_ptr;
1394                         ret = read_one_chunk(root, &key, sb, chunk);
1395                         BUG_ON(ret);
1396                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
1397                         len = btrfs_chunk_item_size(num_stripes);
1398                 } else {
1399                         BUG();
1400                 }
1401                 ptr += len;
1402                 sb_ptr += len;
1403                 cur += len;
1404         }
1405         return 0;
1406 }
1407
1408 int btrfs_read_chunk_tree(struct btrfs_root *root)
1409 {
1410         struct btrfs_path *path;
1411         struct extent_buffer *leaf;
1412         struct btrfs_key key;
1413         struct btrfs_key found_key;
1414         int ret;
1415         int slot;
1416
1417         root = root->fs_info->chunk_root;
1418
1419         path = btrfs_alloc_path();
1420         if (!path)
1421                 return -ENOMEM;
1422
1423         /* first we search for all of the device items, and then we
1424          * read in all of the chunk items.  This way we can create chunk
1425          * mappings that reference all of the devices that are afound
1426          */
1427         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
1428         key.offset = 0;
1429         key.type = 0;
1430 again:
1431         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1432         while(1) {
1433                 leaf = path->nodes[0];
1434                 slot = path->slots[0];
1435                 if (slot >= btrfs_header_nritems(leaf)) {
1436                         ret = btrfs_next_leaf(root, path);
1437                         if (ret == 0)
1438                                 continue;
1439                         if (ret < 0)
1440                                 goto error;
1441                         break;
1442                 }
1443                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1444                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
1445                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
1446                                 break;
1447                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
1448                                 struct btrfs_dev_item *dev_item;
1449                                 dev_item = btrfs_item_ptr(leaf, slot,
1450                                                   struct btrfs_dev_item);
1451                                 ret = read_one_dev(root, leaf, dev_item);
1452                                 BUG_ON(ret);
1453                         }
1454                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
1455                         struct btrfs_chunk *chunk;
1456                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
1457                         ret = read_one_chunk(root, &found_key, leaf, chunk);
1458                 }
1459                 path->slots[0]++;
1460         }
1461         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
1462                 key.objectid = 0;
1463                 btrfs_release_path(root, path);
1464                 goto again;
1465         }
1466
1467         btrfs_free_path(path);
1468         ret = 0;
1469 error:
1470         return ret;
1471 }
1472