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 <linux/random.h>
  23 #include <asm/div64.h>
  24 #include "ctree.h"
  25 #include "extent_map.h"
  26 #include "disk-io.h"
  27 #include "transaction.h"
  28 #include "print-tree.h"
  29 #include "volumes.h"
  30
  31 struct map_lookup {
  32         u64 type;
  33         int io_align;
  34         int io_width;
  35         int stripe_len;
  36         int sector_size;
  37         int num_stripes;
  38         int sub_stripes;
  39         struct btrfs_bio_stripe stripes[];
  40 };
  41
  42 #define map_lookup_size(n) (sizeof(struct map_lookup) + \
  43                             (sizeof(struct btrfs_bio_stripe) * (n)))
  44
  45 static DEFINE_MUTEX(uuid_mutex);
  46 static LIST_HEAD(fs_uuids);
  47
  48 void btrfs_lock_volumes(void)
  49 {
  50         mutex_lock(&uuid_mutex);
  51 }
  52
  53 void btrfs_unlock_volumes(void)
  54 {
  55         mutex_unlock(&uuid_mutex);
  56 }
  57
  58 int btrfs_cleanup_fs_uuids(void)
  59 {
  60         struct btrfs_fs_devices *fs_devices;
  61         struct list_head *uuid_cur;
  62         struct list_head *devices_cur;
  63         struct btrfs_device *dev;
  64
  65         list_for_each(uuid_cur, &fs_uuids) {
  66                 fs_devices = list_entry(uuid_cur, struct btrfs_fs_devices,
  67                                         list);
  68                 while(!list_empty(&fs_devices->devices)) {
  69                         devices_cur = fs_devices->devices.next;
  70                         dev = list_entry(devices_cur, struct btrfs_device,
  71                                          dev_list);
  72                         if (dev->bdev) {
  73                                 close_bdev_excl(dev->bdev);
  74                                 fs_devices->open_devices--;
  75                         }
  76                         list_del(&dev->dev_list);
  77                         kfree(dev->name);
  78                         kfree(dev);
  79                 }
  80         }
  81         return 0;
  82 }
  83
  84 static struct btrfs_device *__find_device(struct list_head *head, u64 devid,
  85                                           u8 *uuid)
  86 {
  87         struct btrfs_device *dev;
  88         struct list_head *cur;
  89
  90         list_for_each(cur, head) {
  91                 dev = list_entry(cur, struct btrfs_device, dev_list);
  92                 if (dev->devid == devid &&
  93                     (!uuid || !memcmp(dev->uuid, uuid, BTRFS_UUID_SIZE))) {
  94                         return dev;
  95                 }
  96         }
  97         return NULL;
  98 }
  99
 100 static struct btrfs_fs_devices *find_fsid(u8 *fsid)
 101 {
 102         struct list_head *cur;
 103         struct btrfs_fs_devices *fs_devices;
 104
 105         list_for_each(cur, &fs_uuids) {
 106                 fs_devices = list_entry(cur, struct btrfs_fs_devices, list);
 107                 if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
 108                         return fs_devices;
 109         }
 110         return NULL;
 111 }
 112
 113 static int device_list_add(const char *path,
 114                            struct btrfs_super_block *disk_super,
 115                            u64 devid, struct btrfs_fs_devices **fs_devices_ret)
 116 {
 117         struct btrfs_device *device;
 118         struct btrfs_fs_devices *fs_devices;
 119         u64 found_transid = btrfs_super_generation(disk_super);
 120
 121         fs_devices = find_fsid(disk_super->fsid);
 122         if (!fs_devices) {
 123                 fs_devices = kzalloc(sizeof(*fs_devices), GFP_NOFS);
 124                 if (!fs_devices)
 125                         return -ENOMEM;
 126                 INIT_LIST_HEAD(&fs_devices->devices);
 127                 INIT_LIST_HEAD(&fs_devices->alloc_list);
 128                 list_add(&fs_devices->list, &fs_uuids);
 129                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
 130                 fs_devices->latest_devid = devid;
 131                 fs_devices->latest_trans = found_transid;
 132                 device = NULL;
 133         } else {
 134                 device = __find_device(&fs_devices->devices, devid,
 135                                        disk_super->dev_item.uuid);
 136         }
 137         if (!device) {
 138                 device = kzalloc(sizeof(*device), GFP_NOFS);
 139                 if (!device) {
 140                         /* we can safely leave the fs_devices entry around */
 141                         return -ENOMEM;
 142                 }
 143                 device->devid = devid;
 144                 memcpy(device->uuid, disk_super->dev_item.uuid,
 145                        BTRFS_UUID_SIZE);
 146                 device->barriers = 1;
 147                 spin_lock_init(&device->io_lock);
 148                 device->name = kstrdup(path, GFP_NOFS);
 149                 if (!device->name) {
 150                         kfree(device);
 151                         return -ENOMEM;
 152                 }
 153                 list_add(&device->dev_list, &fs_devices->devices);
 154                 list_add(&device->dev_alloc_list, &fs_devices->alloc_list);
 155                 fs_devices->num_devices++;
 156         }
 157
 158         if (found_transid > fs_devices->latest_trans) {
 159                 fs_devices->latest_devid = devid;
 160                 fs_devices->latest_trans = found_transid;
 161         }
 162         *fs_devices_ret = fs_devices;
 163         return 0;
 164 }
 165
 166 int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
 167 {
 168         struct list_head *head = &fs_devices->devices;
 169         struct list_head *cur;
 170         struct btrfs_device *device;
 171
 172         mutex_lock(&uuid_mutex);
 173 again:
 174         list_for_each(cur, head) {
 175                 device = list_entry(cur, struct btrfs_device, dev_list);
 176                 if (!device->in_fs_metadata) {
 177                         if (device->bdev) {
 178                                 close_bdev_excl(device->bdev);
 179                                 fs_devices->open_devices--;
 180                         }
 181                         list_del(&device->dev_list);
 182                         list_del(&device->dev_alloc_list);
 183                         fs_devices->num_devices--;
 184                         kfree(device->name);
 185                         kfree(device);
 186                         goto again;
 187                 }
 188         }
 189         mutex_unlock(&uuid_mutex);
 190         return 0;
 191 }
 192
 193 int btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 194 {
 195         struct list_head *head = &fs_devices->devices;
 196         struct list_head *cur;
 197         struct btrfs_device *device;
 198
 199         mutex_lock(&uuid_mutex);
 200         list_for_each(cur, head) {
 201                 device = list_entry(cur, struct btrfs_device, dev_list);
 202                 if (device->bdev) {
 203                         close_bdev_excl(device->bdev);
 204                         fs_devices->open_devices--;
 205                 }
 206                 device->bdev = NULL;
 207                 device->in_fs_metadata = 0;
 208         }
 209         fs_devices->mounted = 0;
 210         mutex_unlock(&uuid_mutex);
 211         return 0;
 212 }
 213
 214 int btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
 215                        int flags, void *holder)
 216 {
 217         struct block_device *bdev;
 218         struct list_head *head = &fs_devices->devices;
 219         struct list_head *cur;
 220         struct btrfs_device *device;
 221         struct block_device *latest_bdev = NULL;
 222         struct buffer_head *bh;
 223         struct btrfs_super_block *disk_super;
 224         u64 latest_devid = 0;
 225         u64 latest_transid = 0;
 226         u64 transid;
 227         u64 devid;
 228         int ret = 0;
 229
 230         mutex_lock(&uuid_mutex);
 231         if (fs_devices->mounted)
 232                 goto out;
 233
 234         list_for_each(cur, head) {
 235                 device = list_entry(cur, struct btrfs_device, dev_list);
 236                 if (device->bdev)
 237                         continue;
 238
 239                 if (!device->name)
 240                         continue;
 241
 242                 bdev = open_bdev_excl(device->name, flags, holder);
 243
 244                 if (IS_ERR(bdev)) {
 245                         printk("open %s failed\n", device->name);
 246                         goto error;
 247                 }
 248                 set_blocksize(bdev, 4096);
 249
 250                 bh = __bread(bdev, BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
 251                 if (!bh)
 252                         goto error_close;
 253
 254                 disk_super = (struct btrfs_super_block *)bh->b_data;
 255                 if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
 256                     sizeof(disk_super->magic)))
 257                         goto error_brelse;
 258
 259                 devid = le64_to_cpu(disk_super->dev_item.devid);
 260                 if (devid != device->devid)
 261                         goto error_brelse;
 262
 263                 transid = btrfs_super_generation(disk_super);
 264                 if (!latest_transid || transid > latest_transid) {
 265                         latest_devid = devid;
 266                         latest_transid = transid;
 267                         latest_bdev = bdev;
 268                 }
 269
 270                 device->bdev = bdev;
 271                 device->in_fs_metadata = 0;
 272                 fs_devices->open_devices++;
 273                 continue;
 274
 275 error_brelse:
 276                 brelse(bh);
 277 error_close:
 278                 close_bdev_excl(bdev);
 279 error:
 280                 continue;
 281         }
 282         if (fs_devices->open_devices == 0) {
 283                 ret = -EIO;
 284                 goto out;
 285         }
 286         fs_devices->mounted = 1;
 287         fs_devices->latest_bdev = latest_bdev;
 288         fs_devices->latest_devid = latest_devid;
 289         fs_devices->latest_trans = latest_transid;
 290 out:
 291         mutex_unlock(&uuid_mutex);
 292         return ret;
 293 }
 294
 295 int btrfs_scan_one_device(const char *path, int flags, void *holder,
 296                           struct btrfs_fs_devices **fs_devices_ret)
 297 {
 298         struct btrfs_super_block *disk_super;
 299         struct block_device *bdev;
 300         struct buffer_head *bh;
 301         int ret;
 302         u64 devid;
 303         u64 transid;
 304
 305         mutex_lock(&uuid_mutex);
 306
 307         bdev = open_bdev_excl(path, flags, holder);
 308
 309         if (IS_ERR(bdev)) {
 310                 ret = PTR_ERR(bdev);
 311                 goto error;
 312         }
 313
 314         ret = set_blocksize(bdev, 4096);
 315         if (ret)
 316                 goto error_close;
 317         bh = __bread(bdev, BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
 318         if (!bh) {
 319                 ret = -EIO;
 320                 goto error_close;
 321         }
 322         disk_super = (struct btrfs_super_block *)bh->b_data;
 323         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
 324             sizeof(disk_super->magic))) {
 325                 ret = -EINVAL;
 326                 goto error_brelse;
 327         }
 328         devid = le64_to_cpu(disk_super->dev_item.devid);
 329         transid = btrfs_super_generation(disk_super);
 330         if (disk_super->label[0])
 331                 printk("device label %s ", disk_super->label);
 332         else {
 333                 /* FIXME, make a readl uuid parser */
 334                 printk("device fsid %llx-%llx ",
 335                        *(unsigned long long *)disk_super->fsid,
 336                        *(unsigned long long *)(disk_super->fsid + 8));
 337         }
 338         printk("devid %Lu transid %Lu %s\n", devid, transid, path);
 339         ret = device_list_add(path, disk_super, devid, fs_devices_ret);
 340
 341 error_brelse:
 342         brelse(bh);
 343 error_close:
 344         close_bdev_excl(bdev);
 345 error:
 346         mutex_unlock(&uuid_mutex);
 347         return ret;
 348 }
 349
 350 /*
 351  * this uses a pretty simple search, the expectation is that it is
 352  * called very infrequently and that a given device has a small number
 353  * of extents
 354  */
 355 static int find_free_dev_extent(struct btrfs_trans_handle *trans,
 356                                 struct btrfs_device *device,
 357                                 struct btrfs_path *path,
 358                                 u64 num_bytes, u64 *start)
 359 {
 360         struct btrfs_key key;
 361         struct btrfs_root *root = device->dev_root;
 362         struct btrfs_dev_extent *dev_extent = NULL;
 363         u64 hole_size = 0;
 364         u64 last_byte = 0;
 365         u64 search_start = 0;
 366         u64 search_end = device->total_bytes;
 367         int ret;
 368         int slot = 0;
 369         int start_found;
 370         struct extent_buffer *l;
 371
 372         start_found = 0;
 373         path->reada = 2;
 374
 375         /* FIXME use last free of some kind */
 376
 377         /* we don't want to overwrite the superblock on the drive,
 378          * so we make sure to start at an offset of at least 1MB
 379          */
 380         search_start = max((u64)1024 * 1024, search_start);
 381
 382         if (root->fs_info->alloc_start + num_bytes <= device->total_bytes)
 383                 search_start = max(root->fs_info->alloc_start, search_start);
 384
 385         key.objectid = device->devid;
 386         key.offset = search_start;
 387         key.type = BTRFS_DEV_EXTENT_KEY;
 388         ret = btrfs_search_slot(trans, root, &key, path, 0, 0);
 389         if (ret < 0)
 390                 goto error;
 391         ret = btrfs_previous_item(root, path, 0, key.type);
 392         if (ret < 0)
 393                 goto error;
 394         l = path->nodes[0];
 395         btrfs_item_key_to_cpu(l, &key, path->slots[0]);
 396         while (1) {
 397                 l = path->nodes[0];
 398                 slot = path->slots[0];
 399                 if (slot >= btrfs_header_nritems(l)) {
 400                         ret = btrfs_next_leaf(root, path);
 401                         if (ret == 0)
 402                                 continue;
 403                         if (ret < 0)
 404                                 goto error;
 405 no_more_items:
 406                         if (!start_found) {
 407                                 if (search_start >= search_end) {
 408                                         ret = -ENOSPC;
 409                                         goto error;
 410                                 }
 411                                 *start = search_start;
 412                                 start_found = 1;
 413                                 goto check_pending;
 414                         }
 415                         *start = last_byte > search_start ?
 416                                 last_byte : search_start;
 417                         if (search_end <= *start) {
 418                                 ret = -ENOSPC;
 419                                 goto error;
 420                         }
 421                         goto check_pending;
 422                 }
 423                 btrfs_item_key_to_cpu(l, &key, slot);
 424
 425                 if (key.objectid < device->devid)
 426                         goto next;
 427
 428                 if (key.objectid > device->devid)
 429                         goto no_more_items;
 430
 431                 if (key.offset >= search_start && key.offset > last_byte &&
 432                     start_found) {
 433                         if (last_byte < search_start)
 434                                 last_byte = search_start;
 435                         hole_size = key.offset - last_byte;
 436                         if (key.offset > last_byte &&
 437                             hole_size >= num_bytes) {
 438                                 *start = last_byte;
 439                                 goto check_pending;
 440                         }
 441                 }
 442                 if (btrfs_key_type(&key) != BTRFS_DEV_EXTENT_KEY) {
 443                         goto next;
 444                 }
 445
 446                 start_found = 1;
 447                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
 448                 last_byte = key.offset + btrfs_dev_extent_length(l, dev_extent);
 449 next:
 450                 path->slots[0]++;
 451                 cond_resched();
 452         }
 453 check_pending:
 454         /* we have to make sure we didn't find an extent that has already
 455          * been allocated by the map tree or the original allocation
 456          */
 457         btrfs_release_path(root, path);
 458         BUG_ON(*start < search_start);
 459
 460         if (*start + num_bytes > search_end) {
 461                 ret = -ENOSPC;
 462                 goto error;
 463         }
 464         /* check for pending inserts here */
 465         return 0;
 466
 467 error:
 468         btrfs_release_path(root, path);
 469         return ret;
 470 }
 471
 472 int btrfs_free_dev_extent(struct btrfs_trans_handle *trans,
 473                           struct btrfs_device *device,
 474                           u64 start)
 475 {
 476         int ret;
 477         struct btrfs_path *path;
 478         struct btrfs_root *root = device->dev_root;
 479         struct btrfs_key key;
 480         struct btrfs_key found_key;
 481         struct extent_buffer *leaf = NULL;
 482         struct btrfs_dev_extent *extent = NULL;
 483
 484         path = btrfs_alloc_path();
 485         if (!path)
 486                 return -ENOMEM;
 487
 488         key.objectid = device->devid;
 489         key.offset = start;
 490         key.type = BTRFS_DEV_EXTENT_KEY;
 491
 492         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 493         if (ret > 0) {
 494                 ret = btrfs_previous_item(root, path, key.objectid,
 495                                           BTRFS_DEV_EXTENT_KEY);
 496                 BUG_ON(ret);
 497                 leaf = path->nodes[0];
 498                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 499                 extent = btrfs_item_ptr(leaf, path->slots[0],
 500                                         struct btrfs_dev_extent);
 501                 BUG_ON(found_key.offset > start || found_key.offset +
 502                        btrfs_dev_extent_length(leaf, extent) < start);
 503                 ret = 0;
 504         } else if (ret == 0) {
 505                 leaf = path->nodes[0];
 506                 extent = btrfs_item_ptr(leaf, path->slots[0],
 507                                         struct btrfs_dev_extent);
 508         }
 509         BUG_ON(ret);
 510
 511         if (device->bytes_used > 0)
 512                 device->bytes_used -= btrfs_dev_extent_length(leaf, extent);
 513         ret = btrfs_del_item(trans, root, path);
 514         BUG_ON(ret);
 515
 516         btrfs_free_path(path);
 517         return ret;
 518 }
 519
 520 int btrfs_alloc_dev_extent(struct btrfs_trans_handle *trans,
 521                            struct btrfs_device *device,
 522                            u64 chunk_tree, u64 chunk_objectid,
 523                            u64 chunk_offset,
 524                            u64 num_bytes, u64 *start)
 525 {
 526         int ret;
 527         struct btrfs_path *path;
 528         struct btrfs_root *root = device->dev_root;
 529         struct btrfs_dev_extent *extent;
 530         struct extent_buffer *leaf;
 531         struct btrfs_key key;
 532
 533         WARN_ON(!device->in_fs_metadata);
 534         path = btrfs_alloc_path();
 535         if (!path)
 536                 return -ENOMEM;
 537
 538         ret = find_free_dev_extent(trans, device, path, num_bytes, start);
 539         if (ret) {
 540                 goto err;
 541         }
 542
 543         key.objectid = device->devid;
 544         key.offset = *start;
 545         key.type = BTRFS_DEV_EXTENT_KEY;
 546         ret = btrfs_insert_empty_item(trans, root, path, &key,
 547                                       sizeof(*extent));
 548         BUG_ON(ret);
 549
 550         leaf = path->nodes[0];
 551         extent = btrfs_item_ptr(leaf, path->slots[0],
 552                                 struct btrfs_dev_extent);
 553         btrfs_set_dev_extent_chunk_tree(leaf, extent, chunk_tree);
 554         btrfs_set_dev_extent_chunk_objectid(leaf, extent, chunk_objectid);
 555         btrfs_set_dev_extent_chunk_offset(leaf, extent, chunk_offset);
 556
 557         write_extent_buffer(leaf, root->fs_info->chunk_tree_uuid,
 558                     (unsigned long)btrfs_dev_extent_chunk_tree_uuid(extent),
 559                     BTRFS_UUID_SIZE);
 560
 561         btrfs_set_dev_extent_length(leaf, extent, num_bytes);
 562         btrfs_mark_buffer_dirty(leaf);
 563 err:
 564         btrfs_free_path(path);
 565         return ret;
 566 }
 567
 568 static int find_next_chunk(struct btrfs_root *root, u64 objectid, u64 *offset)
 569 {
 570         struct btrfs_path *path;
 571         int ret;
 572         struct btrfs_key key;
 573         struct btrfs_chunk *chunk;
 574         struct btrfs_key found_key;
 575
 576         path = btrfs_alloc_path();
 577         BUG_ON(!path);
 578
 579         key.objectid = objectid;
 580         key.offset = (u64)-1;
 581         key.type = BTRFS_CHUNK_ITEM_KEY;
 582
 583         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 584         if (ret < 0)
 585                 goto error;
 586
 587         BUG_ON(ret == 0);
 588
 589         ret = btrfs_previous_item(root, path, 0, BTRFS_CHUNK_ITEM_KEY);
 590         if (ret) {
 591                 *offset = 0;
 592         } else {
 593                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 594                                       path->slots[0]);
 595                 if (found_key.objectid != objectid)
 596                         *offset = 0;
 597                 else {
 598                         chunk = btrfs_item_ptr(path->nodes[0], path->slots[0],
 599                                                struct btrfs_chunk);
 600                         *offset = found_key.offset +
 601                                 btrfs_chunk_length(path->nodes[0], chunk);
 602                 }
 603         }
 604         ret = 0;
 605 error:
 606         btrfs_free_path(path);
 607         return ret;
 608 }
 609
 610 static int find_next_devid(struct btrfs_root *root, struct btrfs_path *path,
 611                            u64 *objectid)
 612 {
 613         int ret;
 614         struct btrfs_key key;
 615         struct btrfs_key found_key;
 616
 617         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
 618         key.type = BTRFS_DEV_ITEM_KEY;
 619         key.offset = (u64)-1;
 620
 621         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 622         if (ret < 0)
 623                 goto error;
 624
 625         BUG_ON(ret == 0);
 626
 627         ret = btrfs_previous_item(root, path, BTRFS_DEV_ITEMS_OBJECTID,
 628                                   BTRFS_DEV_ITEM_KEY);
 629         if (ret) {
 630                 *objectid = 1;
 631         } else {
 632                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
 633                                       path->slots[0]);
 634                 *objectid = found_key.offset + 1;
 635         }
 636         ret = 0;
 637 error:
 638         btrfs_release_path(root, path);
 639         return ret;
 640 }
 641
 642 /*
 643  * the device information is stored in the chunk root
 644  * the btrfs_device struct should be fully filled in
 645  */
 646 int btrfs_add_device(struct btrfs_trans_handle *trans,
 647                      struct btrfs_root *root,
 648                      struct btrfs_device *device)
 649 {
 650         int ret;
 651         struct btrfs_path *path;
 652         struct btrfs_dev_item *dev_item;
 653         struct extent_buffer *leaf;
 654         struct btrfs_key key;
 655         unsigned long ptr;
 656         u64 free_devid = 0;
 657
 658         root = root->fs_info->chunk_root;
 659
 660         path = btrfs_alloc_path();
 661         if (!path)
 662                 return -ENOMEM;
 663
 664         ret = find_next_devid(root, path, &free_devid);
 665         if (ret)
 666                 goto out;
 667
 668         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
 669         key.type = BTRFS_DEV_ITEM_KEY;
 670         key.offset = free_devid;
 671
 672         ret = btrfs_insert_empty_item(trans, root, path, &key,
 673                                       sizeof(*dev_item));
 674         if (ret)
 675                 goto out;
 676
 677         leaf = path->nodes[0];
 678         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
 679
 680         device->devid = free_devid;
 681         btrfs_set_device_id(leaf, dev_item, device->devid);
 682         btrfs_set_device_type(leaf, dev_item, device->type);
 683         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
 684         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
 685         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
 686         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
 687         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
 688         btrfs_set_device_group(leaf, dev_item, 0);
 689         btrfs_set_device_seek_speed(leaf, dev_item, 0);
 690         btrfs_set_device_bandwidth(leaf, dev_item, 0);
 691
 692         ptr = (unsigned long)btrfs_device_uuid(dev_item);
 693         write_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
 694         btrfs_mark_buffer_dirty(leaf);
 695         ret = 0;
 696
 697 out:
 698         btrfs_free_path(path);
 699         return ret;
 700 }
 701
 702 static int btrfs_rm_dev_item(struct btrfs_root *root,
 703                              struct btrfs_device *device)
 704 {
 705         int ret;
 706         struct btrfs_path *path;
 707         struct block_device *bdev = device->bdev;
 708         struct btrfs_device *next_dev;
 709         struct btrfs_key key;
 710         u64 total_bytes;
 711         struct btrfs_fs_devices *fs_devices;
 712         struct btrfs_trans_handle *trans;
 713
 714         root = root->fs_info->chunk_root;
 715
 716         path = btrfs_alloc_path();
 717         if (!path)
 718                 return -ENOMEM;
 719
 720         trans = btrfs_start_transaction(root, 1);
 721         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
 722         key.type = BTRFS_DEV_ITEM_KEY;
 723         key.offset = device->devid;
 724
 725         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 726         if (ret < 0)
 727                 goto out;
 728
 729         if (ret > 0) {
 730                 ret = -ENOENT;
 731                 goto out;
 732         }
 733
 734         ret = btrfs_del_item(trans, root, path);
 735         if (ret)
 736                 goto out;
 737
 738         /*
 739          * at this point, the device is zero sized.  We want to
 740          * remove it from the devices list and zero out the old super
 741          */
 742         list_del_init(&device->dev_list);
 743         list_del_init(&device->dev_alloc_list);
 744         fs_devices = root->fs_info->fs_devices;
 745
 746         next_dev = list_entry(fs_devices->devices.next, struct btrfs_device,
 747                               dev_list);
 748         if (bdev == root->fs_info->sb->s_bdev)
 749                 root->fs_info->sb->s_bdev = next_dev->bdev;
 750         if (bdev == fs_devices->latest_bdev)
 751                 fs_devices->latest_bdev = next_dev->bdev;
 752
 753         total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
 754         btrfs_set_super_num_devices(&root->fs_info->super_copy,
 755                                     total_bytes - 1);
 756 out:
 757         btrfs_free_path(path);
 758         btrfs_commit_transaction(trans, root);
 759         return ret;
 760 }
 761
 762 int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 763 {
 764         struct btrfs_device *device;
 765         struct block_device *bdev;
 766         struct buffer_head *bh = NULL;
 767         struct btrfs_super_block *disk_super;
 768         u64 all_avail;
 769         u64 devid;
 770         int ret = 0;
 771
 772         mutex_lock(&root->fs_info->fs_mutex);
 773         mutex_lock(&uuid_mutex);
 774
 775         all_avail = root->fs_info->avail_data_alloc_bits |
 776                 root->fs_info->avail_system_alloc_bits |
 777                 root->fs_info->avail_metadata_alloc_bits;
 778
 779         if ((all_avail & BTRFS_BLOCK_GROUP_RAID10) &&
 780             btrfs_super_num_devices(&root->fs_info->super_copy) <= 4) {
 781                 printk("btrfs: unable to go below four devices on raid10\n");
 782                 ret = -EINVAL;
 783                 goto out;
 784         }
 785
 786         if ((all_avail & BTRFS_BLOCK_GROUP_RAID1) &&
 787             btrfs_super_num_devices(&root->fs_info->super_copy) <= 2) {
 788                 printk("btrfs: unable to go below two devices on raid1\n");
 789                 ret = -EINVAL;
 790                 goto out;
 791         }
 792
 793         if (strcmp(device_path, "missing") == 0) {
 794                 struct list_head *cur;
 795                 struct list_head *devices;
 796                 struct btrfs_device *tmp;
 797
 798                 device = NULL;
 799                 devices = &root->fs_info->fs_devices->devices;
 800                 list_for_each(cur, devices) {
 801                         tmp = list_entry(cur, struct btrfs_device, dev_list);
 802                         if (tmp->in_fs_metadata && !tmp->bdev) {
 803                                 device = tmp;
 804                                 break;
 805                         }
 806                 }
 807                 bdev = NULL;
 808                 bh = NULL;
 809                 disk_super = NULL;
 810                 if (!device) {
 811                         printk("btrfs: no missing devices found to remove\n");
 812                         goto out;
 813                 }
 814
 815         } else {
 816                 bdev = open_bdev_excl(device_path, 0,
 817                                       root->fs_info->bdev_holder);
 818                 if (IS_ERR(bdev)) {
 819                         ret = PTR_ERR(bdev);
 820                         goto out;
 821                 }
 822
 823                 bh = __bread(bdev, BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
 824                 if (!bh) {
 825                         ret = -EIO;
 826                         goto error_close;
 827                 }
 828                 disk_super = (struct btrfs_super_block *)bh->b_data;
 829                 if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
 830                     sizeof(disk_super->magic))) {
 831                         ret = -ENOENT;
 832                         goto error_brelse;
 833                 }
 834                 if (memcmp(disk_super->fsid, root->fs_info->fsid,
 835                            BTRFS_FSID_SIZE)) {
 836                         ret = -ENOENT;
 837                         goto error_brelse;
 838                 }
 839                 devid = le64_to_cpu(disk_super->dev_item.devid);
 840                 device = btrfs_find_device(root, devid, NULL);
 841                 if (!device) {
 842                         ret = -ENOENT;
 843                         goto error_brelse;
 844                 }
 845
 846         }
 847         root->fs_info->fs_devices->num_devices--;
 848         root->fs_info->fs_devices->open_devices--;
 849
 850         ret = btrfs_shrink_device(device, 0);
 851         if (ret)
 852                 goto error_brelse;
 853
 854
 855         ret = btrfs_rm_dev_item(root->fs_info->chunk_root, device);
 856         if (ret)
 857                 goto error_brelse;
 858
 859         if (bh) {
 860                 /* make sure this device isn't detected as part of
 861                  * the FS anymore
 862                  */
 863                 memset(&disk_super->magic, 0, sizeof(disk_super->magic));
 864                 set_buffer_dirty(bh);
 865                 sync_dirty_buffer(bh);
 866
 867                 brelse(bh);
 868         }
 869
 870         if (device->bdev) {
 871                 /* one close for the device struct or super_block */
 872                 close_bdev_excl(device->bdev);
 873         }
 874         if (bdev) {
 875                 /* one close for us */
 876                 close_bdev_excl(bdev);
 877         }
 878         kfree(device->name);
 879         kfree(device);
 880         ret = 0;
 881         goto out;
 882
 883 error_brelse:
 884         brelse(bh);
 885 error_close:
 886         if (bdev)
 887                 close_bdev_excl(bdev);
 888 out:
 889         mutex_unlock(&uuid_mutex);
 890         mutex_unlock(&root->fs_info->fs_mutex);
 891         return ret;
 892 }
 893
 894 int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
 895 {
 896         struct btrfs_trans_handle *trans;
 897         struct btrfs_device *device;
 898         struct block_device *bdev;
 899         struct list_head *cur;
 900         struct list_head *devices;
 901         u64 total_bytes;
 902         int ret = 0;
 903
 904
 905         bdev = open_bdev_excl(device_path, 0, root->fs_info->bdev_holder);
 906         if (!bdev) {
 907                 return -EIO;
 908         }
 909         mutex_lock(&root->fs_info->fs_mutex);
 910         trans = btrfs_start_transaction(root, 1);
 911         devices = &root->fs_info->fs_devices->devices;
 912         list_for_each(cur, devices) {
 913                 device = list_entry(cur, struct btrfs_device, dev_list);
 914                 if (device->bdev == bdev) {
 915                         ret = -EEXIST;
 916                         goto out;
 917                 }
 918         }
 919
 920         device = kzalloc(sizeof(*device), GFP_NOFS);
 921         if (!device) {
 922                 /* we can safely leave the fs_devices entry around */
 923                 ret = -ENOMEM;
 924                 goto out_close_bdev;
 925         }
 926
 927         device->barriers = 1;
 928         generate_random_uuid(device->uuid);
 929         spin_lock_init(&device->io_lock);
 930         device->name = kstrdup(device_path, GFP_NOFS);
 931         if (!device->name) {
 932                 kfree(device);
 933                 goto out_close_bdev;
 934         }
 935         device->io_width = root->sectorsize;
 936         device->io_align = root->sectorsize;
 937         device->sector_size = root->sectorsize;
 938         device->total_bytes = i_size_read(bdev->bd_inode);
 939         device->dev_root = root->fs_info->dev_root;
 940         device->bdev = bdev;
 941         device->in_fs_metadata = 1;
 942
 943         ret = btrfs_add_device(trans, root, device);
 944         if (ret)
 945                 goto out_close_bdev;
 946
 947         total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
 948         btrfs_set_super_total_bytes(&root->fs_info->super_copy,
 949                                     total_bytes + device->total_bytes);
 950
 951         total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
 952         btrfs_set_super_num_devices(&root->fs_info->super_copy,
 953                                     total_bytes + 1);
 954
 955         list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
 956         list_add(&device->dev_alloc_list,
 957                  &root->fs_info->fs_devices->alloc_list);
 958         root->fs_info->fs_devices->num_devices++;
 959         root->fs_info->fs_devices->open_devices++;
 960 out:
 961         btrfs_end_transaction(trans, root);
 962         mutex_unlock(&root->fs_info->fs_mutex);
 963         return ret;
 964
 965 out_close_bdev:
 966         close_bdev_excl(bdev);
 967         goto out;
 968 }
 969
 970 int btrfs_update_device(struct btrfs_trans_handle *trans,
 971                         struct btrfs_device *device)
 972 {
 973         int ret;
 974         struct btrfs_path *path;
 975         struct btrfs_root *root;
 976         struct btrfs_dev_item *dev_item;
 977         struct extent_buffer *leaf;
 978         struct btrfs_key key;
 979
 980         root = device->dev_root->fs_info->chunk_root;
 981
 982         path = btrfs_alloc_path();
 983         if (!path)
 984                 return -ENOMEM;
 985
 986         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
 987         key.type = BTRFS_DEV_ITEM_KEY;
 988         key.offset = device->devid;
 989
 990         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
 991         if (ret < 0)
 992                 goto out;
 993
 994         if (ret > 0) {
 995                 ret = -ENOENT;
 996                 goto out;
 997         }
 998
 999         leaf = path->nodes[0];
1000         dev_item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_dev_item);
1001
1002         btrfs_set_device_id(leaf, dev_item, device->devid);
1003         btrfs_set_device_type(leaf, dev_item, device->type);
1004         btrfs_set_device_io_align(leaf, dev_item, device->io_align);
1005         btrfs_set_device_io_width(leaf, dev_item, device->io_width);
1006         btrfs_set_device_sector_size(leaf, dev_item, device->sector_size);
1007         btrfs_set_device_total_bytes(leaf, dev_item, device->total_bytes);
1008         btrfs_set_device_bytes_used(leaf, dev_item, device->bytes_used);
1009         btrfs_mark_buffer_dirty(leaf);
1010
1011 out:
1012         btrfs_free_path(path);
1013         return ret;
1014 }
1015
1016 int btrfs_grow_device(struct btrfs_trans_handle *trans,
1017                       struct btrfs_device *device, u64 new_size)
1018 {
1019         struct btrfs_super_block *super_copy =
1020                 &device->dev_root->fs_info->super_copy;
1021         u64 old_total = btrfs_super_total_bytes(super_copy);
1022         u64 diff = new_size - device->total_bytes;
1023
1024         btrfs_set_super_total_bytes(super_copy, old_total + diff);
1025         return btrfs_update_device(trans, device);
1026 }
1027
1028 static int btrfs_free_chunk(struct btrfs_trans_handle *trans,
1029                             struct btrfs_root *root,
1030                             u64 chunk_tree, u64 chunk_objectid,
1031                             u64 chunk_offset)
1032 {
1033         int ret;
1034         struct btrfs_path *path;
1035         struct btrfs_key key;
1036
1037         root = root->fs_info->chunk_root;
1038         path = btrfs_alloc_path();
1039         if (!path)
1040                 return -ENOMEM;
1041
1042         key.objectid = chunk_objectid;
1043         key.offset = chunk_offset;
1044         key.type = BTRFS_CHUNK_ITEM_KEY;
1045
1046         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1047         BUG_ON(ret);
1048
1049         ret = btrfs_del_item(trans, root, path);
1050         BUG_ON(ret);
1051
1052         btrfs_free_path(path);
1053         return 0;
1054 }
1055
1056 int btrfs_del_sys_chunk(struct btrfs_root *root, u64 chunk_objectid, u64
1057                         chunk_offset)
1058 {
1059         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
1060         struct btrfs_disk_key *disk_key;
1061         struct btrfs_chunk *chunk;
1062         u8 *ptr;
1063         int ret = 0;
1064         u32 num_stripes;
1065         u32 array_size;
1066         u32 len = 0;
1067         u32 cur;
1068         struct btrfs_key key;
1069
1070         array_size = btrfs_super_sys_array_size(super_copy);
1071
1072         ptr = super_copy->sys_chunk_array;
1073         cur = 0;
1074
1075         while (cur < array_size) {
1076                 disk_key = (struct btrfs_disk_key *)ptr;
1077                 btrfs_disk_key_to_cpu(&key, disk_key);
1078
1079                 len = sizeof(*disk_key);
1080
1081                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
1082                         chunk = (struct btrfs_chunk *)(ptr + len);
1083                         num_stripes = btrfs_stack_chunk_num_stripes(chunk);
1084                         len += btrfs_chunk_item_size(num_stripes);
1085                 } else {
1086                         ret = -EIO;
1087                         break;
1088                 }
1089                 if (key.objectid == chunk_objectid &&
1090                     key.offset == chunk_offset) {
1091                         memmove(ptr, ptr + len, array_size - (cur + len));
1092                         array_size -= len;
1093                         btrfs_set_super_sys_array_size(super_copy, array_size);
1094                 } else {
1095                         ptr += len;
1096                         cur += len;
1097                 }
1098         }
1099         return ret;
1100 }
1101
1102
1103 int btrfs_relocate_chunk(struct btrfs_root *root,
1104                          u64 chunk_tree, u64 chunk_objectid,
1105                          u64 chunk_offset)
1106 {
1107         struct extent_map_tree *em_tree;
1108         struct btrfs_root *extent_root;
1109         struct btrfs_trans_handle *trans;
1110         struct extent_map *em;
1111         struct map_lookup *map;
1112         int ret;
1113         int i;
1114
1115         printk("btrfs relocating chunk %llu\n",
1116                (unsigned long long)chunk_offset);
1117         root = root->fs_info->chunk_root;
1118         extent_root = root->fs_info->extent_root;
1119         em_tree = &root->fs_info->mapping_tree.map_tree;
1120
1121         /* step one, relocate all the extents inside this chunk */
1122         ret = btrfs_shrink_extent_tree(extent_root, chunk_offset);
1123         BUG_ON(ret);
1124
1125         trans = btrfs_start_transaction(root, 1);
1126         BUG_ON(!trans);
1127
1128         /*
1129          * step two, delete the device extents and the
1130          * chunk tree entries
1131          */
1132         spin_lock(&em_tree->lock);
1133         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
1134         spin_unlock(&em_tree->lock);
1135
1136         BUG_ON(em->start > chunk_offset ||
1137                em->start + em->len < chunk_offset);
1138         map = (struct map_lookup *)em->bdev;
1139
1140         for (i = 0; i < map->num_stripes; i++) {
1141                 ret = btrfs_free_dev_extent(trans, map->stripes[i].dev,
1142                                             map->stripes[i].physical);
1143                 BUG_ON(ret);
1144
1145                 if (map->stripes[i].dev) {
1146                         ret = btrfs_update_device(trans, map->stripes[i].dev);
1147                         BUG_ON(ret);
1148                 }
1149         }
1150         ret = btrfs_free_chunk(trans, root, chunk_tree, chunk_objectid,
1151                                chunk_offset);
1152
1153         BUG_ON(ret);
1154
1155         if (map->type & BTRFS_BLOCK_GROUP_SYSTEM) {
1156                 ret = btrfs_del_sys_chunk(root, chunk_objectid, chunk_offset);
1157                 BUG_ON(ret);
1158         }
1159
1160         spin_lock(&em_tree->lock);
1161         remove_extent_mapping(em_tree, em);
1162         kfree(map);
1163         em->bdev = NULL;
1164
1165         /* once for the tree */
1166         free_extent_map(em);
1167         spin_unlock(&em_tree->lock);
1168
1169         /* once for us */
1170         free_extent_map(em);
1171
1172         btrfs_end_transaction(trans, root);
1173         return 0;
1174 }
1175
1176 static u64 div_factor(u64 num, int factor)
1177 {
1178         if (factor == 10)
1179                 return num;
1180         num *= factor;
1181         do_div(num, 10);
1182         return num;
1183 }
1184
1185
1186 int btrfs_balance(struct btrfs_root *dev_root)
1187 {
1188         int ret;
1189         struct list_head *cur;
1190         struct list_head *devices = &dev_root->fs_info->fs_devices->devices;
1191         struct btrfs_device *device;
1192         u64 old_size;
1193         u64 size_to_free;
1194         struct btrfs_path *path;
1195         struct btrfs_key key;
1196         struct btrfs_chunk *chunk;
1197         struct btrfs_root *chunk_root = dev_root->fs_info->chunk_root;
1198         struct btrfs_trans_handle *trans;
1199         struct btrfs_key found_key;
1200
1201
1202         dev_root = dev_root->fs_info->dev_root;
1203
1204         mutex_lock(&dev_root->fs_info->fs_mutex);
1205         /* step one make some room on all the devices */
1206         list_for_each(cur, devices) {
1207                 device = list_entry(cur, struct btrfs_device, dev_list);
1208                 old_size = device->total_bytes;
1209                 size_to_free = div_factor(old_size, 1);
1210                 size_to_free = min(size_to_free, (u64)1 * 1024 * 1024);
1211                 if (device->total_bytes - device->bytes_used > size_to_free)
1212                         continue;
1213
1214                 ret = btrfs_shrink_device(device, old_size - size_to_free);
1215                 BUG_ON(ret);
1216
1217                 trans = btrfs_start_transaction(dev_root, 1);
1218                 BUG_ON(!trans);
1219
1220                 ret = btrfs_grow_device(trans, device, old_size);
1221                 BUG_ON(ret);
1222
1223                 btrfs_end_transaction(trans, dev_root);
1224         }
1225
1226         /* step two, relocate all the chunks */
1227         path = btrfs_alloc_path();
1228         BUG_ON(!path);
1229
1230         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1231         key.offset = (u64)-1;
1232         key.type = BTRFS_CHUNK_ITEM_KEY;
1233
1234         while(1) {
1235                 ret = btrfs_search_slot(NULL, chunk_root, &key, path, 0, 0);
1236                 if (ret < 0)
1237                         goto error;
1238
1239                 /*
1240                  * this shouldn't happen, it means the last relocate
1241                  * failed
1242                  */
1243                 if (ret == 0)
1244                         break;
1245
1246                 ret = btrfs_previous_item(chunk_root, path, 0,
1247                                           BTRFS_CHUNK_ITEM_KEY);
1248                 if (ret) {
1249                         break;
1250                 }
1251                 btrfs_item_key_to_cpu(path->nodes[0], &found_key,
1252                                       path->slots[0]);
1253                 if (found_key.objectid != key.objectid)
1254                         break;
1255                 chunk = btrfs_item_ptr(path->nodes[0],
1256                                        path->slots[0],
1257                                        struct btrfs_chunk);
1258                 key.offset = found_key.offset;
1259                 /* chunk zero is special */
1260                 if (key.offset == 0)
1261                         break;
1262
1263                 ret = btrfs_relocate_chunk(chunk_root,
1264                                            chunk_root->root_key.objectid,
1265                                            found_key.objectid,
1266                                            found_key.offset);
1267                 BUG_ON(ret);
1268                 btrfs_release_path(chunk_root, path);
1269         }
1270         ret = 0;
1271 error:
1272         btrfs_free_path(path);
1273         mutex_unlock(&dev_root->fs_info->fs_mutex);
1274         return ret;
1275 }
1276
1277 /*
1278  * shrinking a device means finding all of the device extents past
1279  * the new size, and then following the back refs to the chunks.
1280  * The chunk relocation code actually frees the device extent
1281  */
1282 int btrfs_shrink_device(struct btrfs_device *device, u64 new_size)
1283 {
1284         struct btrfs_trans_handle *trans;
1285         struct btrfs_root *root = device->dev_root;
1286         struct btrfs_dev_extent *dev_extent = NULL;
1287         struct btrfs_path *path;
1288         u64 length;
1289         u64 chunk_tree;
1290         u64 chunk_objectid;
1291         u64 chunk_offset;
1292         int ret;
1293         int slot;
1294         struct extent_buffer *l;
1295         struct btrfs_key key;
1296         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
1297         u64 old_total = btrfs_super_total_bytes(super_copy);
1298         u64 diff = device->total_bytes - new_size;
1299
1300
1301         path = btrfs_alloc_path();
1302         if (!path)
1303                 return -ENOMEM;
1304
1305         trans = btrfs_start_transaction(root, 1);
1306         if (!trans) {
1307                 ret = -ENOMEM;
1308                 goto done;
1309         }
1310
1311         path->reada = 2;
1312
1313         device->total_bytes = new_size;
1314         ret = btrfs_update_device(trans, device);
1315         if (ret) {
1316                 btrfs_end_transaction(trans, root);
1317                 goto done;
1318         }
1319         WARN_ON(diff > old_total);
1320         btrfs_set_super_total_bytes(super_copy, old_total - diff);
1321         btrfs_end_transaction(trans, root);
1322
1323         key.objectid = device->devid;
1324         key.offset = (u64)-1;
1325         key.type = BTRFS_DEV_EXTENT_KEY;
1326
1327         while (1) {
1328                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1329                 if (ret < 0)
1330                         goto done;
1331
1332                 ret = btrfs_previous_item(root, path, 0, key.type);
1333                 if (ret < 0)
1334                         goto done;
1335                 if (ret) {
1336                         ret = 0;
1337                         goto done;
1338                 }
1339
1340                 l = path->nodes[0];
1341                 slot = path->slots[0];
1342                 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
1343
1344                 if (key.objectid != device->devid)
1345                         goto done;
1346
1347                 dev_extent = btrfs_item_ptr(l, slot, struct btrfs_dev_extent);
1348                 length = btrfs_dev_extent_length(l, dev_extent);
1349
1350                 if (key.offset + length <= new_size)
1351                         goto done;
1352
1353                 chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
1354                 chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
1355                 chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
1356                 btrfs_release_path(root, path);
1357
1358                 ret = btrfs_relocate_chunk(root, chunk_tree, chunk_objectid,
1359                                            chunk_offset);
1360                 if (ret)
1361                         goto done;
1362         }
1363
1364 done:
1365         btrfs_free_path(path);
1366         return ret;
1367 }
1368
1369 int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
1370                            struct btrfs_root *root,
1371                            struct btrfs_key *key,
1372                            struct btrfs_chunk *chunk, int item_size)
1373 {
1374         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
1375         struct btrfs_disk_key disk_key;
1376         u32 array_size;
1377         u8 *ptr;
1378
1379         array_size = btrfs_super_sys_array_size(super_copy);
1380         if (array_size + item_size > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE)
1381                 return -EFBIG;
1382
1383         ptr = super_copy->sys_chunk_array + array_size;
1384         btrfs_cpu_key_to_disk(&disk_key, key);
1385         memcpy(ptr, &disk_key, sizeof(disk_key));
1386         ptr += sizeof(disk_key);
1387         memcpy(ptr, chunk, item_size);
1388         item_size += sizeof(disk_key);
1389         btrfs_set_super_sys_array_size(super_copy, array_size + item_size);
1390         return 0;
1391 }
1392
1393 static u64 chunk_bytes_by_type(u64 type, u64 calc_size, int num_stripes,
1394                                int sub_stripes)
1395 {
1396         if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
1397                 return calc_size;
1398         else if (type & BTRFS_BLOCK_GROUP_RAID10)
1399                 return calc_size * (num_stripes / sub_stripes);
1400         else
1401                 return calc_size * num_stripes;
1402 }
1403
1404
1405 int btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
1406                       struct btrfs_root *extent_root, u64 *start,
1407                       u64 *num_bytes, u64 type)
1408 {
1409         u64 dev_offset;
1410         struct btrfs_fs_info *info = extent_root->fs_info;
1411         struct btrfs_root *chunk_root = extent_root->fs_info->chunk_root;
1412         struct btrfs_path *path;
1413         struct btrfs_stripe *stripes;
1414         struct btrfs_device *device = NULL;
1415         struct btrfs_chunk *chunk;
1416         struct list_head private_devs;
1417         struct list_head *dev_list;
1418         struct list_head *cur;
1419         struct extent_map_tree *em_tree;
1420         struct map_lookup *map;
1421         struct extent_map *em;
1422         int min_stripe_size = 1 * 1024 * 1024;
1423         u64 physical;
1424         u64 calc_size = 1024 * 1024 * 1024;
1425         u64 max_chunk_size = calc_size;
1426         u64 min_free;
1427         u64 avail;
1428         u64 max_avail = 0;
1429         u64 percent_max;
1430         int num_stripes = 1;
1431         int min_stripes = 1;
1432         int sub_stripes = 0;
1433         int looped = 0;
1434         int ret;
1435         int index;
1436         int stripe_len = 64 * 1024;
1437         struct btrfs_key key;
1438
1439         if ((type & BTRFS_BLOCK_GROUP_RAID1) &&
1440             (type & BTRFS_BLOCK_GROUP_DUP)) {
1441                 WARN_ON(1);
1442                 type &= ~BTRFS_BLOCK_GROUP_DUP;
1443         }
1444         dev_list = &extent_root->fs_info->fs_devices->alloc_list;
1445         if (list_empty(dev_list))
1446                 return -ENOSPC;
1447
1448         if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
1449                 num_stripes = extent_root->fs_info->fs_devices->open_devices;
1450                 min_stripes = 2;
1451         }
1452         if (type & (BTRFS_BLOCK_GROUP_DUP)) {
1453                 num_stripes = 2;
1454                 min_stripes = 2;
1455         }
1456         if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
1457                 num_stripes = min_t(u64, 2,
1458                             extent_root->fs_info->fs_devices->open_devices);
1459                 if (num_stripes < 2)
1460                         return -ENOSPC;
1461                 min_stripes = 2;
1462         }
1463         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
1464                 num_stripes = extent_root->fs_info->fs_devices->open_devices;
1465                 if (num_stripes < 4)
1466                         return -ENOSPC;
1467                 num_stripes &= ~(u32)1;
1468                 sub_stripes = 2;
1469                 min_stripes = 4;
1470         }
1471
1472         if (type & BTRFS_BLOCK_GROUP_DATA) {
1473                 max_chunk_size = 10 * calc_size;
1474                 min_stripe_size = 64 * 1024 * 1024;
1475         } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
1476                 max_chunk_size = 4 * calc_size;
1477                 min_stripe_size = 32 * 1024 * 1024;
1478         } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
1479                 calc_size = 8 * 1024 * 1024;
1480                 max_chunk_size = calc_size * 2;
1481                 min_stripe_size = 1 * 1024 * 1024;
1482         }
1483
1484         path = btrfs_alloc_path();
1485         if (!path)
1486                 return -ENOMEM;
1487
1488         /* we don't want a chunk larger than 10% of the FS */
1489         percent_max = div_factor(btrfs_super_total_bytes(&info->super_copy), 1);
1490         max_chunk_size = min(percent_max, max_chunk_size);
1491
1492 again:
1493         if (calc_size * num_stripes > max_chunk_size) {
1494                 calc_size = max_chunk_size;
1495                 do_div(calc_size, num_stripes);
1496                 do_div(calc_size, stripe_len);
1497                 calc_size *= stripe_len;
1498         }
1499         /* we don't want tiny stripes */
1500         calc_size = max_t(u64, min_stripe_size, calc_size);
1501
1502         do_div(calc_size, stripe_len);
1503         calc_size *= stripe_len;
1504
1505         INIT_LIST_HEAD(&private_devs);
1506         cur = dev_list->next;
1507         index = 0;
1508
1509         if (type & BTRFS_BLOCK_GROUP_DUP)
1510                 min_free = calc_size * 2;
1511         else
1512                 min_free = calc_size;
1513
1514         /* we add 1MB because we never use the first 1MB of the device */
1515         min_free += 1024 * 1024;
1516
1517         /* build a private list of devices we will allocate from */
1518         while(index < num_stripes) {
1519                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
1520
1521                 if (device->total_bytes > device->bytes_used)
1522                         avail = device->total_bytes - device->bytes_used;
1523                 else
1524                         avail = 0;
1525                 cur = cur->next;
1526
1527                 if (device->in_fs_metadata && avail >= min_free) {
1528                         u64 ignored_start = 0;
1529                         ret = find_free_dev_extent(trans, device, path,
1530                                                    min_free,
1531                                                    &ignored_start);
1532                         if (ret == 0) {
1533                                 list_move_tail(&device->dev_alloc_list,
1534                                                &private_devs);
1535                                 index++;
1536                                 if (type & BTRFS_BLOCK_GROUP_DUP)
1537                                         index++;
1538                         }
1539                 } else if (device->in_fs_metadata && avail > max_avail)
1540                         max_avail = avail;
1541                 if (cur == dev_list)
1542                         break;
1543         }
1544         if (index < num_stripes) {
1545                 list_splice(&private_devs, dev_list);
1546                 if (index >= min_stripes) {
1547                         num_stripes = index;
1548                         if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
1549                                 num_stripes /= sub_stripes;
1550                                 num_stripes *= sub_stripes;
1551                         }
1552                         looped = 1;
1553                         goto again;
1554                 }
1555                 if (!looped && max_avail > 0) {
1556                         looped = 1;
1557                         calc_size = max_avail;
1558                         goto again;
1559                 }
1560                 btrfs_free_path(path);
1561                 return -ENOSPC;
1562         }
1563         key.objectid = BTRFS_FIRST_CHUNK_TREE_OBJECTID;
1564         key.type = BTRFS_CHUNK_ITEM_KEY;
1565         ret = find_next_chunk(chunk_root, BTRFS_FIRST_CHUNK_TREE_OBJECTID,
1566                               &key.offset);
1567         if (ret) {
1568                 btrfs_free_path(path);
1569                 return ret;
1570         }
1571
1572         chunk = kmalloc(btrfs_chunk_item_size(num_stripes), GFP_NOFS);
1573         if (!chunk) {
1574                 btrfs_free_path(path);
1575                 return -ENOMEM;
1576         }
1577
1578         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
1579         if (!map) {
1580                 kfree(chunk);
1581                 btrfs_free_path(path);
1582                 return -ENOMEM;
1583         }
1584         btrfs_free_path(path);
1585         path = NULL;
1586
1587         stripes = &chunk->stripe;
1588         *num_bytes = chunk_bytes_by_type(type, calc_size,
1589                                          num_stripes, sub_stripes);
1590
1591         index = 0;
1592         while(index < num_stripes) {
1593                 struct btrfs_stripe *stripe;
1594                 BUG_ON(list_empty(&private_devs));
1595                 cur = private_devs.next;
1596                 device = list_entry(cur, struct btrfs_device, dev_alloc_list);
1597
1598                 /* loop over this device again if we're doing a dup group */
1599                 if (!(type & BTRFS_BLOCK_GROUP_DUP) ||
1600                     (index == num_stripes - 1))
1601                         list_move_tail(&device->dev_alloc_list, dev_list);
1602
1603                 ret = btrfs_alloc_dev_extent(trans, device,
1604                              info->chunk_root->root_key.objectid,
1605                              BTRFS_FIRST_CHUNK_TREE_OBJECTID, key.offset,
1606                              calc_size, &dev_offset);
1607                 BUG_ON(ret);
1608                 device->bytes_used += calc_size;
1609                 ret = btrfs_update_device(trans, device);
1610                 BUG_ON(ret);
1611
1612                 map->stripes[index].dev = device;
1613                 map->stripes[index].physical = dev_offset;
1614                 stripe = stripes + index;
1615                 btrfs_set_stack_stripe_devid(stripe, device->devid);
1616                 btrfs_set_stack_stripe_offset(stripe, dev_offset);
1617                 memcpy(stripe->dev_uuid, device->uuid, BTRFS_UUID_SIZE);
1618                 physical = dev_offset;
1619                 index++;
1620         }
1621         BUG_ON(!list_empty(&private_devs));
1622
1623         /* key was set above */
1624         btrfs_set_stack_chunk_length(chunk, *num_bytes);
1625         btrfs_set_stack_chunk_owner(chunk, extent_root->root_key.objectid);
1626         btrfs_set_stack_chunk_stripe_len(chunk, stripe_len);
1627         btrfs_set_stack_chunk_type(chunk, type);
1628         btrfs_set_stack_chunk_num_stripes(chunk, num_stripes);
1629         btrfs_set_stack_chunk_io_align(chunk, stripe_len);
1630         btrfs_set_stack_chunk_io_width(chunk, stripe_len);
1631         btrfs_set_stack_chunk_sector_size(chunk, extent_root->sectorsize);
1632         btrfs_set_stack_chunk_sub_stripes(chunk, sub_stripes);
1633         map->sector_size = extent_root->sectorsize;
1634         map->stripe_len = stripe_len;
1635         map->io_align = stripe_len;
1636         map->io_width = stripe_len;
1637         map->type = type;
1638         map->num_stripes = num_stripes;
1639         map->sub_stripes = sub_stripes;
1640
1641         ret = btrfs_insert_item(trans, chunk_root, &key, chunk,
1642                                 btrfs_chunk_item_size(num_stripes));
1643         BUG_ON(ret);
1644         *start = key.offset;;
1645
1646         em = alloc_extent_map(GFP_NOFS);
1647         if (!em)
1648                 return -ENOMEM;
1649         em->bdev = (struct block_device *)map;
1650         em->start = key.offset;
1651         em->len = *num_bytes;
1652         em->block_start = 0;
1653
1654         if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
1655                 ret = btrfs_add_system_chunk(trans, chunk_root, &key,
1656                                     chunk, btrfs_chunk_item_size(num_stripes));
1657                 BUG_ON(ret);
1658         }
1659         kfree(chunk);
1660
1661         em_tree = &extent_root->fs_info->mapping_tree.map_tree;
1662         spin_lock(&em_tree->lock);
1663         ret = add_extent_mapping(em_tree, em);
1664         spin_unlock(&em_tree->lock);
1665         BUG_ON(ret);
1666         free_extent_map(em);
1667         return ret;
1668 }
1669
1670 void btrfs_mapping_init(struct btrfs_mapping_tree *tree)
1671 {
1672         extent_map_tree_init(&tree->map_tree, GFP_NOFS);
1673 }
1674
1675 void btrfs_mapping_tree_free(struct btrfs_mapping_tree *tree)
1676 {
1677         struct extent_map *em;
1678
1679         while(1) {
1680                 spin_lock(&tree->map_tree.lock);
1681                 em = lookup_extent_mapping(&tree->map_tree, 0, (u64)-1);
1682                 if (em)
1683                         remove_extent_mapping(&tree->map_tree, em);
1684                 spin_unlock(&tree->map_tree.lock);
1685                 if (!em)
1686                         break;
1687                 kfree(em->bdev);
1688                 /* once for us */
1689                 free_extent_map(em);
1690                 /* once for the tree */
1691                 free_extent_map(em);
1692         }
1693 }
1694
1695 int btrfs_num_copies(struct btrfs_mapping_tree *map_tree, u64 logical, u64 len)
1696 {
1697         struct extent_map *em;
1698         struct map_lookup *map;
1699         struct extent_map_tree *em_tree = &map_tree->map_tree;
1700         int ret;
1701
1702         spin_lock(&em_tree->lock);
1703         em = lookup_extent_mapping(em_tree, logical, len);
1704         spin_unlock(&em_tree->lock);
1705         BUG_ON(!em);
1706
1707         BUG_ON(em->start > logical || em->start + em->len < logical);
1708         map = (struct map_lookup *)em->bdev;
1709         if (map->type & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1))
1710                 ret = map->num_stripes;
1711         else if (map->type & BTRFS_BLOCK_GROUP_RAID10)
1712                 ret = map->sub_stripes;
1713         else
1714                 ret = 1;
1715         free_extent_map(em);
1716         return ret;
1717 }
1718
1719 static int find_live_mirror(struct map_lookup *map, int first, int num,
1720                             int optimal)
1721 {
1722         int i;
1723         if (map->stripes[optimal].dev->bdev)
1724                 return optimal;
1725         for (i = first; i < first + num; i++) {
1726                 if (map->stripes[i].dev->bdev)
1727                         return i;
1728         }
1729         /* we couldn't find one that doesn't fail.  Just return something
1730          * and the io error handling code will clean up eventually
1731          */
1732         return optimal;
1733 }
1734
1735 static int __btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
1736                              u64 logical, u64 *length,
1737                              struct btrfs_multi_bio **multi_ret,
1738                              int mirror_num, struct page *unplug_page)
1739 {
1740         struct extent_map *em;
1741         struct map_lookup *map;
1742         struct extent_map_tree *em_tree = &map_tree->map_tree;
1743         u64 offset;
1744         u64 stripe_offset;
1745         u64 stripe_nr;
1746         int stripes_allocated = 8;
1747         int stripes_required = 1;
1748         int stripe_index;
1749         int i;
1750         int num_stripes;
1751         int max_errors = 0;
1752         struct btrfs_multi_bio *multi = NULL;
1753
1754         if (multi_ret && !(rw & (1 << BIO_RW))) {
1755                 stripes_allocated = 1;
1756         }
1757 again:
1758         if (multi_ret) {
1759                 multi = kzalloc(btrfs_multi_bio_size(stripes_allocated),
1760                                 GFP_NOFS);
1761                 if (!multi)
1762                         return -ENOMEM;
1763
1764                 atomic_set(&multi->error, 0);
1765         }
1766
1767         spin_lock(&em_tree->lock);
1768         em = lookup_extent_mapping(em_tree, logical, *length);
1769         spin_unlock(&em_tree->lock);
1770
1771         if (!em && unplug_page)
1772                 return 0;
1773
1774         if (!em) {
1775                 printk("unable to find logical %Lu len %Lu\n", logical, *length);
1776                 BUG();
1777         }
1778
1779         BUG_ON(em->start > logical || em->start + em->len < logical);
1780         map = (struct map_lookup *)em->bdev;
1781         offset = logical - em->start;
1782
1783         if (mirror_num > map->num_stripes)
1784                 mirror_num = 0;
1785
1786         /* if our multi bio struct is too small, back off and try again */
1787         if (rw & (1 << BIO_RW)) {
1788                 if (map->type & (BTRFS_BLOCK_GROUP_RAID1 |
1789                                  BTRFS_BLOCK_GROUP_DUP)) {
1790                         stripes_required = map->num_stripes;
1791                         max_errors = 1;
1792                 } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1793                         stripes_required = map->sub_stripes;
1794                         max_errors = 1;
1795                 }
1796         }
1797         if (multi_ret && rw == WRITE &&
1798             stripes_allocated < stripes_required) {
1799                 stripes_allocated = map->num_stripes;
1800                 free_extent_map(em);
1801                 kfree(multi);
1802                 goto again;
1803         }
1804         stripe_nr = offset;
1805         /*
1806          * stripe_nr counts the total number of stripes we have to stride
1807          * to get to this block
1808          */
1809         do_div(stripe_nr, map->stripe_len);
1810
1811         stripe_offset = stripe_nr * map->stripe_len;
1812         BUG_ON(offset < stripe_offset);
1813
1814         /* stripe_offset is the offset of this block in its stripe*/
1815         stripe_offset = offset - stripe_offset;
1816
1817         if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
1818                          BTRFS_BLOCK_GROUP_RAID10 |
1819                          BTRFS_BLOCK_GROUP_DUP)) {
1820                 /* we limit the length of each bio to what fits in a stripe */
1821                 *length = min_t(u64, em->len - offset,
1822                               map->stripe_len - stripe_offset);
1823         } else {
1824                 *length = em->len - offset;
1825         }
1826
1827         if (!multi_ret && !unplug_page)
1828                 goto out;
1829
1830         num_stripes = 1;
1831         stripe_index = 0;
1832         if (map->type & BTRFS_BLOCK_GROUP_RAID1) {
1833                 if (unplug_page || (rw & (1 << BIO_RW)))
1834                         num_stripes = map->num_stripes;
1835                 else if (mirror_num)
1836                         stripe_index = mirror_num - 1;
1837                 else {
1838                         stripe_index = find_live_mirror(map, 0,
1839                                             map->num_stripes,
1840                                             current->pid % map->num_stripes);
1841                 }
1842
1843         } else if (map->type & BTRFS_BLOCK_GROUP_DUP) {
1844                 if (rw & (1 << BIO_RW))
1845                         num_stripes = map->num_stripes;
1846                 else if (mirror_num)
1847                         stripe_index = mirror_num - 1;
1848
1849         } else if (map->type & BTRFS_BLOCK_GROUP_RAID10) {
1850                 int factor = map->num_stripes / map->sub_stripes;
1851
1852                 stripe_index = do_div(stripe_nr, factor);
1853                 stripe_index *= map->sub_stripes;
1854
1855                 if (unplug_page || (rw & (1 << BIO_RW)))
1856                         num_stripes = map->sub_stripes;
1857                 else if (mirror_num)
1858                         stripe_index += mirror_num - 1;
1859                 else {
1860                         stripe_index = find_live_mirror(map, stripe_index,
1861                                               map->sub_stripes, stripe_index +
1862                                               current->pid % map->sub_stripes);
1863                 }
1864         } else {
1865                 /*
1866                  * after this do_div call, stripe_nr is the number of stripes
1867                  * on this device we have to walk to find the data, and
1868                  * stripe_index is the number of our device in the stripe array
1869                  */
1870                 stripe_index = do_div(stripe_nr, map->num_stripes);
1871         }
1872         BUG_ON(stripe_index >= map->num_stripes);
1873
1874         for (i = 0; i < num_stripes; i++) {
1875                 if (unplug_page) {
1876                         struct btrfs_device *device;
1877                         struct backing_dev_info *bdi;
1878
1879                         device = map->stripes[stripe_index].dev;
1880                         if (device->bdev) {
1881                                 bdi = blk_get_backing_dev_info(device->bdev);
1882                                 if (bdi->unplug_io_fn) {
1883                                         bdi->unplug_io_fn(bdi, unplug_page);
1884                                 }
1885                         }
1886                 } else {
1887                         multi->stripes[i].physical =
1888                                 map->stripes[stripe_index].physical +
1889                                 stripe_offset + stripe_nr * map->stripe_len;
1890                         multi->stripes[i].dev = map->stripes[stripe_index].dev;
1891                 }
1892                 stripe_index++;
1893         }
1894         if (multi_ret) {
1895                 *multi_ret = multi;
1896                 multi->num_stripes = num_stripes;
1897                 multi->max_errors = max_errors;
1898         }
1899 out:
1900         free_extent_map(em);
1901         return 0;
1902 }
1903
1904 int btrfs_map_block(struct btrfs_mapping_tree *map_tree, int rw,
1905                       u64 logical, u64 *length,
1906                       struct btrfs_multi_bio **multi_ret, int mirror_num)
1907 {
1908         return __btrfs_map_block(map_tree, rw, logical, length, multi_ret,
1909                                  mirror_num, NULL);
1910 }
1911
1912 int btrfs_unplug_page(struct btrfs_mapping_tree *map_tree,
1913                       u64 logical, struct page *page)
1914 {
1915         u64 length = PAGE_CACHE_SIZE;
1916         return __btrfs_map_block(map_tree, READ, logical, &length,
1917                                  NULL, 0, page);
1918 }
1919
1920
1921 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1922 static void end_bio_multi_stripe(struct bio *bio, int err)
1923 #else
1924 static int end_bio_multi_stripe(struct bio *bio,
1925                                    unsigned int bytes_done, int err)
1926 #endif
1927 {
1928         struct btrfs_multi_bio *multi = bio->bi_private;
1929
1930 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1931         if (bio->bi_size)
1932                 return 1;
1933 #endif
1934         if (err)
1935                 atomic_inc(&multi->error);
1936
1937         if (atomic_dec_and_test(&multi->stripes_pending)) {
1938                 bio->bi_private = multi->private;
1939                 bio->bi_end_io = multi->end_io;
1940                 /* only send an error to the higher layers if it is
1941                  * beyond the tolerance of the multi-bio
1942                  */
1943                 if (atomic_read(&multi->error) > multi->max_errors) {
1944                         err = -EIO;
1945                 } else if (err) {
1946                         /*
1947                          * this bio is actually up to date, we didn't
1948                          * go over the max number of errors
1949                          */
1950                         set_bit(BIO_UPTODATE, &bio->bi_flags);
1951                         err = 0;
1952                 }
1953                 kfree(multi);
1954
1955 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1956                 bio_endio(bio, bio->bi_size, err);
1957 #else
1958                 bio_endio(bio, err);
1959 #endif
1960         } else {
1961                 bio_put(bio);
1962         }
1963 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1964         return 0;
1965 #endif
1966 }
1967
1968 int btrfs_map_bio(struct btrfs_root *root, int rw, struct bio *bio,
1969                   int mirror_num)
1970 {
1971         struct btrfs_mapping_tree *map_tree;
1972         struct btrfs_device *dev;
1973         struct bio *first_bio = bio;
1974         u64 logical = bio->bi_sector << 9;
1975         u64 length = 0;
1976         u64 map_length;
1977         struct btrfs_multi_bio *multi = NULL;
1978         int ret;
1979         int dev_nr = 0;
1980         int total_devs = 1;
1981
1982         length = bio->bi_size;
1983         map_tree = &root->fs_info->mapping_tree;
1984         map_length = length;
1985
1986         ret = btrfs_map_block(map_tree, rw, logical, &map_length, &multi,
1987                               mirror_num);
1988         BUG_ON(ret);
1989
1990         total_devs = multi->num_stripes;
1991         if (map_length < length) {
1992                 printk("mapping failed logical %Lu bio len %Lu "
1993                        "len %Lu\n", logical, length, map_length);
1994                 BUG();
1995         }
1996         multi->end_io = first_bio->bi_end_io;
1997         multi->private = first_bio->bi_private;
1998         atomic_set(&multi->stripes_pending, multi->num_stripes);
1999
2000         while(dev_nr < total_devs) {
2001                 if (total_devs > 1) {
2002                         if (dev_nr < total_devs - 1) {
2003                                 bio = bio_clone(first_bio, GFP_NOFS);
2004                                 BUG_ON(!bio);
2005                         } else {
2006                                 bio = first_bio;
2007                         }
2008                         bio->bi_private = multi;
2009                         bio->bi_end_io = end_bio_multi_stripe;
2010                 }
2011                 bio->bi_sector = multi->stripes[dev_nr].physical >> 9;
2012                 dev = multi->stripes[dev_nr].dev;
2013                 if (dev && dev->bdev) {
2014                         bio->bi_bdev = dev->bdev;
2015                         spin_lock(&dev->io_lock);
2016                         dev->total_ios++;
2017                         spin_unlock(&dev->io_lock);
2018                         submit_bio(rw, bio);
2019                 } else {
2020                         bio->bi_bdev = root->fs_info->fs_devices->latest_bdev;
2021                         bio->bi_sector = logical >> 9;
2022 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
2023                         bio_endio(bio, bio->bi_size, -EIO);
2024 #else
2025                         bio_endio(bio, -EIO);
2026 #endif
2027                 }
2028                 dev_nr++;
2029         }
2030         if (total_devs == 1)
2031                 kfree(multi);
2032         return 0;
2033 }
2034
2035 struct btrfs_device *btrfs_find_device(struct btrfs_root *root, u64 devid,
2036                                        u8 *uuid)
2037 {
2038         struct list_head *head = &root->fs_info->fs_devices->devices;
2039
2040         return __find_device(head, devid, uuid);
2041 }
2042
2043 static struct btrfs_device *add_missing_dev(struct btrfs_root *root,
2044                                             u64 devid, u8 *dev_uuid)
2045 {
2046         struct btrfs_device *device;
2047         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
2048
2049         device = kzalloc(sizeof(*device), GFP_NOFS);
2050         list_add(&device->dev_list,
2051                  &fs_devices->devices);
2052         list_add(&device->dev_alloc_list,
2053                  &fs_devices->alloc_list);
2054         device->barriers = 1;
2055         device->dev_root = root->fs_info->dev_root;
2056         device->devid = devid;
2057         fs_devices->num_devices++;
2058         spin_lock_init(&device->io_lock);
2059         memcpy(device->uuid, dev_uuid, BTRFS_UUID_SIZE);
2060         return device;
2061 }
2062
2063
2064 static int read_one_chunk(struct btrfs_root *root, struct btrfs_key *key,
2065                           struct extent_buffer *leaf,
2066                           struct btrfs_chunk *chunk)
2067 {
2068         struct btrfs_mapping_tree *map_tree = &root->fs_info->mapping_tree;
2069         struct map_lookup *map;
2070         struct extent_map *em;
2071         u64 logical;
2072         u64 length;
2073         u64 devid;
2074         u8 uuid[BTRFS_UUID_SIZE];
2075         int num_stripes;
2076         int ret;
2077         int i;
2078
2079         logical = key->offset;
2080         length = btrfs_chunk_length(leaf, chunk);
2081
2082         spin_lock(&map_tree->map_tree.lock);
2083         em = lookup_extent_mapping(&map_tree->map_tree, logical, 1);
2084         spin_unlock(&map_tree->map_tree.lock);
2085
2086         /* already mapped? */
2087         if (em && em->start <= logical && em->start + em->len > logical) {
2088                 free_extent_map(em);
2089                 return 0;
2090         } else if (em) {
2091                 free_extent_map(em);
2092         }
2093
2094         map = kzalloc(sizeof(*map), GFP_NOFS);
2095         if (!map)
2096                 return -ENOMEM;
2097
2098         em = alloc_extent_map(GFP_NOFS);
2099         if (!em)
2100                 return -ENOMEM;
2101         num_stripes = btrfs_chunk_num_stripes(leaf, chunk);
2102         map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
2103         if (!map) {
2104                 free_extent_map(em);
2105                 return -ENOMEM;
2106         }
2107
2108         em->bdev = (struct block_device *)map;
2109         em->start = logical;
2110         em->len = length;
2111         em->block_start = 0;
2112
2113         map->num_stripes = num_stripes;
2114         map->io_width = btrfs_chunk_io_width(leaf, chunk);
2115         map->io_align = btrfs_chunk_io_align(leaf, chunk);
2116         map->sector_size = btrfs_chunk_sector_size(leaf, chunk);
2117         map->stripe_len = btrfs_chunk_stripe_len(leaf, chunk);
2118         map->type = btrfs_chunk_type(leaf, chunk);
2119         map->sub_stripes = btrfs_chunk_sub_stripes(leaf, chunk);
2120         for (i = 0; i < num_stripes; i++) {
2121                 map->stripes[i].physical =
2122                         btrfs_stripe_offset_nr(leaf, chunk, i);
2123                 devid = btrfs_stripe_devid_nr(leaf, chunk, i);
2124                 read_extent_buffer(leaf, uuid, (unsigned long)
2125                                    btrfs_stripe_dev_uuid_nr(chunk, i),
2126                                    BTRFS_UUID_SIZE);
2127                 map->stripes[i].dev = btrfs_find_device(root, devid, uuid);
2128
2129                 if (!map->stripes[i].dev && !btrfs_test_opt(root, DEGRADED)) {
2130                         kfree(map);
2131                         free_extent_map(em);
2132                         return -EIO;
2133                 }
2134                 if (!map->stripes[i].dev) {
2135                         map->stripes[i].dev =
2136                                 add_missing_dev(root, devid, uuid);
2137                         if (!map->stripes[i].dev) {
2138                                 kfree(map);
2139                                 free_extent_map(em);
2140                                 return -EIO;
2141                         }
2142                 }
2143                 map->stripes[i].dev->in_fs_metadata = 1;
2144         }
2145
2146         spin_lock(&map_tree->map_tree.lock);
2147         ret = add_extent_mapping(&map_tree->map_tree, em);
2148         spin_unlock(&map_tree->map_tree.lock);
2149         BUG_ON(ret);
2150         free_extent_map(em);
2151
2152         return 0;
2153 }
2154
2155 static int fill_device_from_item(struct extent_buffer *leaf,
2156                                  struct btrfs_dev_item *dev_item,
2157                                  struct btrfs_device *device)
2158 {
2159         unsigned long ptr;
2160
2161         device->devid = btrfs_device_id(leaf, dev_item);
2162         device->total_bytes = btrfs_device_total_bytes(leaf, dev_item);
2163         device->bytes_used = btrfs_device_bytes_used(leaf, dev_item);
2164         device->type = btrfs_device_type(leaf, dev_item);
2165         device->io_align = btrfs_device_io_align(leaf, dev_item);
2166         device->io_width = btrfs_device_io_width(leaf, dev_item);
2167         device->sector_size = btrfs_device_sector_size(leaf, dev_item);
2168
2169         ptr = (unsigned long)btrfs_device_uuid(dev_item);
2170         read_extent_buffer(leaf, device->uuid, ptr, BTRFS_UUID_SIZE);
2171
2172         return 0;
2173 }
2174
2175 static int read_one_dev(struct btrfs_root *root,
2176                         struct extent_buffer *leaf,
2177                         struct btrfs_dev_item *dev_item)
2178 {
2179         struct btrfs_device *device;
2180         u64 devid;
2181         int ret;
2182         u8 dev_uuid[BTRFS_UUID_SIZE];
2183
2184         devid = btrfs_device_id(leaf, dev_item);
2185         read_extent_buffer(leaf, dev_uuid,
2186                            (unsigned long)btrfs_device_uuid(dev_item),
2187                            BTRFS_UUID_SIZE);
2188         device = btrfs_find_device(root, devid, dev_uuid);
2189         if (!device) {
2190                 printk("warning devid %Lu missing\n", devid);
2191                 device = add_missing_dev(root, devid, dev_uuid);
2192                 if (!device)
2193                         return -ENOMEM;
2194         }
2195
2196         fill_device_from_item(leaf, dev_item, device);
2197         device->dev_root = root->fs_info->dev_root;
2198         device->in_fs_metadata = 1;
2199         ret = 0;
2200 #if 0
2201         ret = btrfs_open_device(device);
2202         if (ret) {
2203                 kfree(device);
2204         }
2205 #endif
2206         return ret;
2207 }
2208
2209 int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf)
2210 {
2211         struct btrfs_dev_item *dev_item;
2212
2213         dev_item = (struct btrfs_dev_item *)offsetof(struct btrfs_super_block,
2214                                                      dev_item);
2215         return read_one_dev(root, buf, dev_item);
2216 }
2217
2218 int btrfs_read_sys_array(struct btrfs_root *root)
2219 {
2220         struct btrfs_super_block *super_copy = &root->fs_info->super_copy;
2221         struct extent_buffer *sb;
2222         struct btrfs_disk_key *disk_key;
2223         struct btrfs_chunk *chunk;
2224         u8 *ptr;
2225         unsigned long sb_ptr;
2226         int ret = 0;
2227         u32 num_stripes;
2228         u32 array_size;
2229         u32 len = 0;
2230         u32 cur;
2231         struct btrfs_key key;
2232
2233         sb = btrfs_find_create_tree_block(root, BTRFS_SUPER_INFO_OFFSET,
2234                                           BTRFS_SUPER_INFO_SIZE);
2235         if (!sb)
2236                 return -ENOMEM;
2237         btrfs_set_buffer_uptodate(sb);
2238         write_extent_buffer(sb, super_copy, 0, BTRFS_SUPER_INFO_SIZE);
2239         array_size = btrfs_super_sys_array_size(super_copy);
2240
2241         ptr = super_copy->sys_chunk_array;
2242         sb_ptr = offsetof(struct btrfs_super_block, sys_chunk_array);
2243         cur = 0;
2244
2245         while (cur < array_size) {
2246                 disk_key = (struct btrfs_disk_key *)ptr;
2247                 btrfs_disk_key_to_cpu(&key, disk_key);
2248
2249                 len = sizeof(*disk_key); ptr += len;
2250                 sb_ptr += len;
2251                 cur += len;
2252
2253                 if (key.type == BTRFS_CHUNK_ITEM_KEY) {
2254                         chunk = (struct btrfs_chunk *)sb_ptr;
2255                         ret = read_one_chunk(root, &key, sb, chunk);
2256                         if (ret)
2257                                 break;
2258                         num_stripes = btrfs_chunk_num_stripes(sb, chunk);
2259                         len = btrfs_chunk_item_size(num_stripes);
2260                 } else {
2261                         ret = -EIO;
2262                         break;
2263                 }
2264                 ptr += len;
2265                 sb_ptr += len;
2266                 cur += len;
2267         }
2268         free_extent_buffer(sb);
2269         return ret;
2270 }
2271
2272 int btrfs_read_chunk_tree(struct btrfs_root *root)
2273 {
2274         struct btrfs_path *path;
2275         struct extent_buffer *leaf;
2276         struct btrfs_key key;
2277         struct btrfs_key found_key;
2278         int ret;
2279         int slot;
2280
2281         root = root->fs_info->chunk_root;
2282
2283         path = btrfs_alloc_path();
2284         if (!path)
2285                 return -ENOMEM;
2286
2287         /* first we search for all of the device items, and then we
2288          * read in all of the chunk items.  This way we can create chunk
2289          * mappings that reference all of the devices that are afound
2290          */
2291         key.objectid = BTRFS_DEV_ITEMS_OBJECTID;
2292         key.offset = 0;
2293         key.type = 0;
2294 again:
2295         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2296         while(1) {
2297                 leaf = path->nodes[0];
2298                 slot = path->slots[0];
2299                 if (slot >= btrfs_header_nritems(leaf)) {
2300                         ret = btrfs_next_leaf(root, path);
2301                         if (ret == 0)
2302                                 continue;
2303                         if (ret < 0)
2304                                 goto error;
2305                         break;
2306                 }
2307                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2308                 if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
2309                         if (found_key.objectid != BTRFS_DEV_ITEMS_OBJECTID)
2310                                 break;
2311                         if (found_key.type == BTRFS_DEV_ITEM_KEY) {
2312                                 struct btrfs_dev_item *dev_item;
2313                                 dev_item = btrfs_item_ptr(leaf, slot,
2314                                                   struct btrfs_dev_item);
2315                                 ret = read_one_dev(root, leaf, dev_item);
2316                                 BUG_ON(ret);
2317                         }
2318                 } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) {
2319                         struct btrfs_chunk *chunk;
2320                         chunk = btrfs_item_ptr(leaf, slot, struct btrfs_chunk);
2321                         ret = read_one_chunk(root, &found_key, leaf, chunk);
2322                 }
2323                 path->slots[0]++;
2324         }
2325         if (key.objectid == BTRFS_DEV_ITEMS_OBJECTID) {
2326                 key.objectid = 0;
2327                 btrfs_release_path(root, path);
2328                 goto again;
2329         }
2330
2331         btrfs_free_path(path);
2332         ret = 0;
2333 error:
2334         return ret;
2335 }
2336