disk-io.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #define _XOPEN_SOURCE 600
  20 #define __USE_XOPEN2K
  21 #define _GNU_SOURCE 1
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <sys/types.h>
  25 #include <sys/stat.h>
  26 #include <fcntl.h>
  27 #include <unistd.h>
  28 #include "kerncompat.h"
  29 #include "radix-tree.h"
  30 #include "ctree.h"
  31 #include "disk-io.h"
  32 #include "volumes.h"
  33 #include "transaction.h"
  34 #include "crc32c.h"
  35 #include "utils.h"
  36 #include "print-tree.h"
  37
  38 static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf)
  39 {
  40
  41         struct btrfs_fs_devices *fs_devices;
  42         int ret = 1;
  43
  44         if (buf->start != btrfs_header_bytenr(buf)) {
  45                 printk("Check tree block failed, want=%Lu, have=%Lu\n",
  46                        buf->start, btrfs_header_bytenr(buf));
  47                 return ret;
  48         }
  49
  50         fs_devices = root->fs_info->fs_devices;
  51         while (fs_devices) {
  52                 if (!memcmp_extent_buffer(buf, fs_devices->fsid,
  53                                           (unsigned long)btrfs_header_fsid(buf),
  54                                           BTRFS_FSID_SIZE)) {
  55                         ret = 0;
  56                         break;
  57                 }
  58                 fs_devices = fs_devices->seed;
  59         }
  60         return ret;
  61 }
  62
  63 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
  64 {
  65         return crc32c(seed, data, len);
  66 }
  67
  68 void btrfs_csum_final(u32 crc, char *result)
  69 {
  70         *(__le32 *)result = ~cpu_to_le32(crc);
  71 }
  72
  73 int csum_tree_block_size(struct extent_buffer *buf, u16 csum_size,
  74                          int verify)
  75 {
  76         char *result;
  77         u32 len;
  78         u32 crc = ~(u32)0;
  79
  80         result = malloc(csum_size * sizeof(char));
  81         if (!result)
  82                 return 1;
  83
  84         len = buf->len - BTRFS_CSUM_SIZE;
  85         crc = crc32c(crc, buf->data + BTRFS_CSUM_SIZE, len);
  86         btrfs_csum_final(crc, result);
  87
  88         if (verify) {
  89                 if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
  90                         printk("checksum verify failed on %llu found %08X "
  91                                "wanted %08X\n", (unsigned long long)buf->start,
  92                                *((u32 *)result), *((u32*)(char *)buf->data));
  93                         free(result);
  94                         return 1;
  95                 }
  96         } else {
  97                 write_extent_buffer(buf, result, 0, csum_size);
  98         }
  99         free(result);
 100         return 0;
 101 }
 102
 103 int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 104                     int verify)
 105 {
 106         u16 csum_size =
 107                 btrfs_super_csum_size(root->fs_info->super_copy);
 108         return csum_tree_block_size(buf, csum_size, verify);
 109 }
 110
 111 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
 112                                             u64 bytenr, u32 blocksize)
 113 {
 114         return find_extent_buffer(&root->fs_info->extent_cache,
 115                                   bytenr, blocksize);
 116 }
 117
 118 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 119                                                  u64 bytenr, u32 blocksize)
 120 {
 121         return alloc_extent_buffer(&root->fs_info->extent_cache, bytenr,
 122                                    blocksize);
 123 }
 124
 125 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 126                          u64 parent_transid)
 127 {
 128         int ret;
 129         struct extent_buffer *eb;
 130         u64 length;
 131         struct btrfs_multi_bio *multi = NULL;
 132         struct btrfs_device *device;
 133
 134         eb = btrfs_find_tree_block(root, bytenr, blocksize);
 135         if (eb && btrfs_buffer_uptodate(eb, parent_transid)) {
 136                 free_extent_buffer(eb);
 137                 return 0;
 138         }
 139
 140         length = blocksize;
 141         ret = btrfs_map_block(&root->fs_info->mapping_tree, READ,
 142                               bytenr, &length, &multi, 0, NULL);
 143         BUG_ON(ret);
 144         device = multi->stripes[0].dev;
 145         device->total_ios++;
 146         blocksize = min(blocksize, (u32)(64 * 1024));
 147         readahead(device->fd, multi->stripes[0].physical, blocksize);
 148         kfree(multi);
 149         return 0;
 150 }
 151
 152 static int verify_parent_transid(struct extent_io_tree *io_tree,
 153                                  struct extent_buffer *eb, u64 parent_transid,
 154                                  int ignore)
 155 {
 156         int ret;
 157
 158         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
 159                 return 0;
 160
 161         if (extent_buffer_uptodate(eb) &&
 162             btrfs_header_generation(eb) == parent_transid) {
 163                 ret = 0;
 164                 goto out;
 165         }
 166         printk("parent transid verify failed on %llu wanted %llu found %llu\n",
 167                (unsigned long long)eb->start,
 168                (unsigned long long)parent_transid,
 169                (unsigned long long)btrfs_header_generation(eb));
 170         if (ignore) {
 171                 printk("Ignoring transid failure\n");
 172                 return 0;
 173         }
 174
 175         ret = 1;
 176 out:
 177         clear_extent_buffer_uptodate(io_tree, eb);
 178         return ret;
 179
 180 }
 181
 182
 183 static int read_whole_eb(struct btrfs_fs_info *info, struct extent_buffer *eb, int mirror)
 184 {
 185         unsigned long offset = 0;
 186         struct btrfs_multi_bio *multi = NULL;
 187         struct btrfs_device *device;
 188         int ret = 0;
 189         u64 read_len;
 190         unsigned long bytes_left = eb->len;
 191
 192         while (bytes_left) {
 193                 read_len = bytes_left;
 194                 ret = btrfs_map_block(&info->mapping_tree, READ,
 195                                       eb->start + offset, &read_len, &multi,
 196                                       mirror, NULL);
 197                 if (ret) {
 198                         printk("Couldn't map the block %Lu\n", eb->start + offset);
 199                         kfree(multi);
 200                         return -EIO;
 201                 }
 202                 device = multi->stripes[0].dev;
 203
 204                 if (device->fd == 0) {
 205                         kfree(multi);
 206                         return -EIO;
 207                 }
 208
 209                 eb->fd = device->fd;
 210                 device->total_ios++;
 211                 eb->dev_bytenr = multi->stripes[0].physical;
 212                 kfree(multi);
 213                 multi = NULL;
 214
 215                 if (read_len > bytes_left)
 216                         read_len = bytes_left;
 217
 218                 ret = read_extent_from_disk(eb, offset, read_len);
 219                 if (ret)
 220                         return -EIO;
 221                 offset += read_len;
 222                 bytes_left -= read_len;
 223         }
 224         return 0;
 225 }
 226
 227 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 228                                      u32 blocksize, u64 parent_transid)
 229 {
 230         int ret;
 231         struct extent_buffer *eb;
 232         u64 best_transid = 0;
 233         int mirror_num = 0;
 234         int good_mirror = 0;
 235         int num_copies;
 236         int ignore = 0;
 237
 238         eb = btrfs_find_create_tree_block(root, bytenr, blocksize);
 239         if (!eb)
 240                 return NULL;
 241
 242         if (btrfs_buffer_uptodate(eb, parent_transid))
 243                 return eb;
 244
 245         while (1) {
 246                 ret = read_whole_eb(root->fs_info, eb, mirror_num);
 247                 if (ret == 0 && check_tree_block(root, eb) == 0 &&
 248                     csum_tree_block(root, eb, 1) == 0 &&
 249                     verify_parent_transid(eb->tree, eb, parent_transid, ignore)
 250                     == 0) {
 251                         btrfs_set_buffer_uptodate(eb);
 252                         return eb;
 253                 }
 254                 if (ignore) {
 255                         if (check_tree_block(root, eb))
 256                                 printk("read block failed check_tree_block\n");
 257                         else
 258                                 printk("Csum didn't match\n");
 259                         break;
 260                 }
 261                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
 262                                               eb->start, eb->len);
 263                 if (num_copies == 1) {
 264                         ignore = 1;
 265                         continue;
 266                 }
 267                 if (btrfs_header_generation(eb) > best_transid) {
 268                         best_transid = btrfs_header_generation(eb);
 269                         good_mirror = mirror_num;
 270                 }
 271                 mirror_num++;
 272                 if (mirror_num > num_copies) {
 273                         mirror_num = good_mirror;
 274                         ignore = 1;
 275                         continue;
 276                 }
 277         }
 278         free_extent_buffer(eb);
 279         return NULL;
 280 }
 281
 282 static int rmw_eb(struct btrfs_fs_info *info,
 283                   struct extent_buffer *eb, struct extent_buffer *orig_eb)
 284 {
 285         int ret;
 286         unsigned long orig_off = 0;
 287         unsigned long dest_off = 0;
 288         unsigned long copy_len = eb->len;
 289
 290         ret = read_whole_eb(info, eb, 0);
 291         if (ret)
 292                 return ret;
 293
 294         if (eb->start + eb->len <= orig_eb->start ||
 295             eb->start >= orig_eb->start + orig_eb->len)
 296                 return 0;
 297         /*
 298          * | ----- orig_eb ------- |
 299          *         | ----- stripe -------  |
 300          *         | ----- orig_eb ------- |
 301          *              | ----- orig_eb ------- |
 302          */
 303         if (eb->start > orig_eb->start)
 304                 orig_off = eb->start - orig_eb->start;
 305         if (orig_eb->start > eb->start)
 306                 dest_off = orig_eb->start - eb->start;
 307
 308         if (copy_len > orig_eb->len - orig_off)
 309                 copy_len = orig_eb->len - orig_off;
 310         if (copy_len > eb->len - dest_off)
 311                 copy_len = eb->len - dest_off;
 312
 313         memcpy(eb->data + dest_off, orig_eb->data + orig_off, copy_len);
 314         return 0;
 315 }
 316
 317 static void split_eb_for_raid56(struct btrfs_fs_info *info,
 318                                 struct extent_buffer *orig_eb,
 319                                struct extent_buffer **ebs,
 320                                u64 stripe_len, u64 *raid_map,
 321                                int num_stripes)
 322 {
 323         struct extent_buffer *eb;
 324         u64 start = orig_eb->start;
 325         u64 this_eb_start;
 326         int i;
 327         int ret;
 328
 329         for (i = 0; i < num_stripes; i++) {
 330                 if (raid_map[i] >= BTRFS_RAID5_P_STRIPE)
 331                         break;
 332
 333                 eb = malloc(sizeof(struct extent_buffer) + stripe_len);
 334                 if (!eb)
 335                         BUG();
 336                 memset(eb, 0, sizeof(struct extent_buffer) + stripe_len);
 337
 338                 eb->start = raid_map[i];
 339                 eb->len = stripe_len;
 340                 eb->refs = 1;
 341                 eb->flags = 0;
 342                 eb->fd = -1;
 343                 eb->dev_bytenr = (u64)-1;
 344
 345                 this_eb_start = raid_map[i];
 346
 347                 if (start > this_eb_start ||
 348                     start + orig_eb->len < this_eb_start + stripe_len) {
 349                         ret = rmw_eb(info, eb, orig_eb);
 350                         BUG_ON(ret);
 351                 } else {
 352                         memcpy(eb->data, orig_eb->data + eb->start - start, stripe_len);
 353                 }
 354                 ebs[i] = eb;
 355         }
 356 }
 357
 358 static int write_raid56_with_parity(struct btrfs_fs_info *info,
 359                                     struct extent_buffer *eb,
 360                                     struct btrfs_multi_bio *multi,
 361                                     u64 stripe_len, u64 *raid_map)
 362 {
 363         struct extent_buffer *ebs[multi->num_stripes], *p_eb = NULL, *q_eb = NULL;
 364         int i;
 365         int j;
 366         int ret;
 367         int alloc_size = eb->len;
 368
 369         if (stripe_len > alloc_size)
 370                 alloc_size = stripe_len;
 371
 372         split_eb_for_raid56(info, eb, ebs, stripe_len, raid_map,
 373                             multi->num_stripes);
 374
 375         for (i = 0; i < multi->num_stripes; i++) {
 376                 struct extent_buffer *new_eb;
 377                 if (raid_map[i] < BTRFS_RAID5_P_STRIPE) {
 378                         ebs[i]->dev_bytenr = multi->stripes[i].physical;
 379                         ebs[i]->fd = multi->stripes[i].dev->fd;
 380                         multi->stripes[i].dev->total_ios++;
 381                         BUG_ON(ebs[i]->start != raid_map[i]);
 382                         continue;
 383                 }
 384                 new_eb = kmalloc(sizeof(*eb) + alloc_size, GFP_NOFS);
 385                 BUG_ON(!new_eb);
 386                 new_eb->dev_bytenr = multi->stripes[i].physical;
 387                 new_eb->fd = multi->stripes[i].dev->fd;
 388                 multi->stripes[i].dev->total_ios++;
 389                 new_eb->len = stripe_len;
 390
 391                 if (raid_map[i] == BTRFS_RAID5_P_STRIPE)
 392                         p_eb = new_eb;
 393                 else if (raid_map[i] == BTRFS_RAID6_Q_STRIPE)
 394                         q_eb = new_eb;
 395         }
 396         if (q_eb) {
 397                 void *pointers[multi->num_stripes];
 398                 ebs[multi->num_stripes - 2] = p_eb;
 399                 ebs[multi->num_stripes - 1] = q_eb;
 400
 401                 for (i = 0; i < multi->num_stripes; i++)
 402                         pointers[i] = ebs[i]->data;
 403
 404                 raid6_gen_syndrome(multi->num_stripes, stripe_len, pointers);
 405         } else {
 406                 ebs[multi->num_stripes - 1] = p_eb;
 407                 memcpy(p_eb->data, ebs[0]->data, stripe_len);
 408                 for (j = 1; j < multi->num_stripes - 1; j++) {
 409                         for (i = 0; i < stripe_len; i += sizeof(unsigned long)) {
 410                                 *(unsigned long *)(p_eb->data + i) ^=
 411                                         *(unsigned long *)(ebs[j]->data + i);
 412                         }
 413                 }
 414         }
 415
 416         for (i = 0; i < multi->num_stripes; i++) {
 417                 ret = write_extent_to_disk(ebs[i]);
 418                 BUG_ON(ret);
 419                 if (ebs[i] != eb)
 420                         kfree(ebs[i]);
 421         }
 422         return 0;
 423 }
 424
 425 int write_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 426                      struct extent_buffer *eb)
 427 {
 428         int ret;
 429         int dev_nr;
 430         u64 length;
 431         u64 *raid_map = NULL;
 432         struct btrfs_multi_bio *multi = NULL;
 433
 434         if (check_tree_block(root, eb))
 435                 BUG();
 436         if (!btrfs_buffer_uptodate(eb, trans->transid))
 437                 BUG();
 438
 439         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
 440         csum_tree_block(root, eb, 0);
 441
 442         dev_nr = 0;
 443         length = eb->len;
 444         ret = btrfs_map_block(&root->fs_info->mapping_tree, WRITE,
 445                               eb->start, &length, &multi, 0, &raid_map);
 446
 447         if (raid_map) {
 448                 ret = write_raid56_with_parity(root->fs_info, eb, multi,
 449                                                length, raid_map);
 450                 BUG_ON(ret);
 451         } else while (dev_nr < multi->num_stripes) {
 452                 BUG_ON(ret);
 453                 eb->fd = multi->stripes[dev_nr].dev->fd;
 454                 eb->dev_bytenr = multi->stripes[dev_nr].physical;
 455                 multi->stripes[dev_nr].dev->total_ios++;
 456                 dev_nr++;
 457                 ret = write_extent_to_disk(eb);
 458                 BUG_ON(ret);
 459         }
 460         kfree(multi);
 461         return 0;
 462 }
 463
 464 int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 465                         u32 stripesize, struct btrfs_root *root,
 466                         struct btrfs_fs_info *fs_info, u64 objectid)
 467 {
 468         root->node = NULL;
 469         root->commit_root = NULL;
 470         root->sectorsize = sectorsize;
 471         root->nodesize = nodesize;
 472         root->leafsize = leafsize;
 473         root->stripesize = stripesize;
 474         root->ref_cows = 0;
 475         root->track_dirty = 0;
 476
 477         root->fs_info = fs_info;
 478         root->objectid = objectid;
 479         root->last_trans = 0;
 480         root->highest_inode = 0;
 481         root->last_inode_alloc = 0;
 482
 483         INIT_LIST_HEAD(&root->dirty_list);
 484         memset(&root->root_key, 0, sizeof(root->root_key));
 485         memset(&root->root_item, 0, sizeof(root->root_item));
 486         root->root_key.objectid = objectid;
 487         return 0;
 488 }
 489
 490 static int update_cowonly_root(struct btrfs_trans_handle *trans,
 491                                struct btrfs_root *root)
 492 {
 493         int ret;
 494         u64 old_root_bytenr;
 495         struct btrfs_root *tree_root = root->fs_info->tree_root;
 496
 497         btrfs_write_dirty_block_groups(trans, root);
 498         while(1) {
 499                 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
 500                 if (old_root_bytenr == root->node->start)
 501                         break;
 502                 btrfs_set_root_bytenr(&root->root_item,
 503                                        root->node->start);
 504                 btrfs_set_root_generation(&root->root_item,
 505                                           trans->transid);
 506                 root->root_item.level = btrfs_header_level(root->node);
 507                 ret = btrfs_update_root(trans, tree_root,
 508                                         &root->root_key,
 509                                         &root->root_item);
 510                 BUG_ON(ret);
 511                 btrfs_write_dirty_block_groups(trans, root);
 512         }
 513         return 0;
 514 }
 515
 516 static int commit_tree_roots(struct btrfs_trans_handle *trans,
 517                              struct btrfs_fs_info *fs_info)
 518 {
 519         struct btrfs_root *root;
 520         struct list_head *next;
 521         struct extent_buffer *eb;
 522         int ret;
 523
 524         if (fs_info->readonly)
 525                 return 0;
 526
 527         eb = fs_info->tree_root->node;
 528         extent_buffer_get(eb);
 529         ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb);
 530         free_extent_buffer(eb);
 531         if (ret)
 532                 return ret;
 533
 534         while(!list_empty(&fs_info->dirty_cowonly_roots)) {
 535                 next = fs_info->dirty_cowonly_roots.next;
 536                 list_del_init(next);
 537                 root = list_entry(next, struct btrfs_root, dirty_list);
 538                 update_cowonly_root(trans, root);
 539                 free_extent_buffer(root->commit_root);
 540                 root->commit_root = NULL;
 541         }
 542
 543         return 0;
 544 }
 545
 546 static int __commit_transaction(struct btrfs_trans_handle *trans,
 547                                 struct btrfs_root *root)
 548 {
 549         u64 start;
 550         u64 end;
 551         struct extent_buffer *eb;
 552         struct extent_io_tree *tree = &root->fs_info->extent_cache;
 553         int ret;
 554
 555         while(1) {
 556                 ret = find_first_extent_bit(tree, 0, &start, &end,
 557                                             EXTENT_DIRTY);
 558                 if (ret)
 559                         break;
 560                 while(start <= end) {
 561                         eb = find_first_extent_buffer(tree, start);
 562                         BUG_ON(!eb || eb->start != start);
 563                         ret = write_tree_block(trans, root, eb);
 564                         BUG_ON(ret);
 565                         start += eb->len;
 566                         clear_extent_buffer_dirty(eb);
 567                         free_extent_buffer(eb);
 568                 }
 569         }
 570         return 0;
 571 }
 572
 573 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 574                              struct btrfs_root *root)
 575 {
 576         u64 transid = trans->transid;
 577         int ret = 0;
 578         struct btrfs_fs_info *fs_info = root->fs_info;
 579
 580         if (root->commit_root == root->node)
 581                 goto commit_tree;
 582
 583         free_extent_buffer(root->commit_root);
 584         root->commit_root = NULL;
 585
 586         btrfs_set_root_bytenr(&root->root_item, root->node->start);
 587         btrfs_set_root_generation(&root->root_item, trans->transid);
 588         root->root_item.level = btrfs_header_level(root->node);
 589         ret = btrfs_update_root(trans, root->fs_info->tree_root,
 590                                 &root->root_key, &root->root_item);
 591         BUG_ON(ret);
 592 commit_tree:
 593         ret = commit_tree_roots(trans, fs_info);
 594         BUG_ON(ret);
 595         ret = __commit_transaction(trans, root);
 596         BUG_ON(ret);
 597         write_ctree_super(trans, root);
 598         btrfs_finish_extent_commit(trans, fs_info->extent_root,
 599                                    &fs_info->pinned_extents);
 600         btrfs_free_transaction(root, trans);
 601         free_extent_buffer(root->commit_root);
 602         root->commit_root = NULL;
 603         fs_info->running_transaction = NULL;
 604         fs_info->last_trans_committed = transid;
 605         return 0;
 606 }
 607
 608 static int find_and_setup_root(struct btrfs_root *tree_root,
 609                                struct btrfs_fs_info *fs_info,
 610                                u64 objectid, struct btrfs_root *root)
 611 {
 612         int ret;
 613         u32 blocksize;
 614         u64 generation;
 615
 616         __setup_root(tree_root->nodesize, tree_root->leafsize,
 617                      tree_root->sectorsize, tree_root->stripesize,
 618                      root, fs_info, objectid);
 619         ret = btrfs_find_last_root(tree_root, objectid,
 620                                    &root->root_item, &root->root_key);
 621         if (ret)
 622                 return ret;
 623
 624         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
 625         generation = btrfs_root_generation(&root->root_item);
 626         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
 627                                      blocksize, generation);
 628         if (!extent_buffer_uptodate(root->node))
 629                 return -EIO;
 630
 631         return 0;
 632 }
 633
 634 static int find_and_setup_log_root(struct btrfs_root *tree_root,
 635                                struct btrfs_fs_info *fs_info,
 636                                struct btrfs_super_block *disk_super)
 637 {
 638         u32 blocksize;
 639         u64 blocknr = btrfs_super_log_root(disk_super);
 640         struct btrfs_root *log_root = malloc(sizeof(struct btrfs_root));
 641
 642         if (!log_root)
 643                 return -ENOMEM;
 644
 645         if (blocknr == 0) {
 646                 free(log_root);
 647                 return 0;
 648         }
 649
 650         blocksize = btrfs_level_size(tree_root,
 651                              btrfs_super_log_root_level(disk_super));
 652
 653         __setup_root(tree_root->nodesize, tree_root->leafsize,
 654                      tree_root->sectorsize, tree_root->stripesize,
 655                      log_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
 656
 657         log_root->node = read_tree_block(tree_root, blocknr,
 658                                      blocksize,
 659                                      btrfs_super_generation(disk_super) + 1);
 660
 661         fs_info->log_root_tree = log_root;
 662
 663         if (!extent_buffer_uptodate(log_root->node)) {
 664                 free_extent_buffer(log_root->node);
 665                 free(log_root);
 666                 fs_info->log_root_tree = NULL;
 667                 return -EIO;
 668         }
 669
 670         return 0;
 671 }
 672
 673
 674 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info,
 675                        struct btrfs_root *root)
 676 {
 677         if (root->node)
 678                 free_extent_buffer(root->node);
 679         if (root->commit_root)
 680                 free_extent_buffer(root->commit_root);
 681         kfree(root);
 682         return 0;
 683 }
 684
 685 static int free_fs_roots(struct btrfs_fs_info *fs_info)
 686 {
 687         struct cache_extent *cache;
 688         struct btrfs_root *root;
 689
 690         while (1) {
 691                 cache = find_first_cache_extent(&fs_info->fs_root_cache, 0);
 692                 if (!cache)
 693                         break;
 694                 root = container_of(cache, struct btrfs_root, cache);
 695                 remove_cache_extent(&fs_info->fs_root_cache, cache);
 696                 btrfs_free_fs_root(fs_info, root);
 697         }
 698         return 0;
 699 }
 700
 701 struct btrfs_root *btrfs_read_fs_root_no_cache(struct btrfs_fs_info *fs_info,
 702                                                struct btrfs_key *location)
 703 {
 704         struct btrfs_root *root;
 705         struct btrfs_root *tree_root = fs_info->tree_root;
 706         struct btrfs_path *path;
 707         struct extent_buffer *l;
 708         u64 generation;
 709         u32 blocksize;
 710         int ret = 0;
 711
 712         root = malloc(sizeof(*root));
 713         if (!root)
 714                 return ERR_PTR(-ENOMEM);
 715         memset(root, 0, sizeof(*root));
 716         if (location->offset == (u64)-1) {
 717                 ret = find_and_setup_root(tree_root, fs_info,
 718                                           location->objectid, root);
 719                 if (ret) {
 720                         free(root);
 721                         return ERR_PTR(ret);
 722                 }
 723                 goto insert;
 724         }
 725
 726         __setup_root(tree_root->nodesize, tree_root->leafsize,
 727                      tree_root->sectorsize, tree_root->stripesize,
 728                      root, fs_info, location->objectid);
 729
 730         path = btrfs_alloc_path();
 731         BUG_ON(!path);
 732         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
 733         if (ret != 0) {
 734                 if (ret > 0)
 735                         ret = -ENOENT;
 736                 goto out;
 737         }
 738         l = path->nodes[0];
 739         read_extent_buffer(l, &root->root_item,
 740                btrfs_item_ptr_offset(l, path->slots[0]),
 741                sizeof(root->root_item));
 742         memcpy(&root->root_key, location, sizeof(*location));
 743         ret = 0;
 744 out:
 745         btrfs_release_path(root, path);
 746         btrfs_free_path(path);
 747         if (ret) {
 748                 free(root);
 749                 return ERR_PTR(ret);
 750         }
 751         generation = btrfs_root_generation(&root->root_item);
 752         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
 753         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
 754                                      blocksize, generation);
 755         BUG_ON(!root->node);
 756 insert:
 757         root->ref_cows = 1;
 758         return root;
 759 }
 760
 761 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 762                                       struct btrfs_key *location)
 763 {
 764         struct btrfs_root *root;
 765         struct cache_extent *cache;
 766         int ret;
 767
 768         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
 769                 return fs_info->tree_root;
 770         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
 771                 return fs_info->extent_root;
 772         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
 773                 return fs_info->chunk_root;
 774         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
 775                 return fs_info->dev_root;
 776         if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
 777                 return fs_info->csum_root;
 778
 779         BUG_ON(location->objectid == BTRFS_TREE_RELOC_OBJECTID ||
 780                location->offset != (u64)-1);
 781
 782         cache = find_cache_extent(&fs_info->fs_root_cache,
 783                                   location->objectid, 1);
 784         if (cache)
 785                 return container_of(cache, struct btrfs_root, cache);
 786
 787         root = btrfs_read_fs_root_no_cache(fs_info, location);
 788         if (IS_ERR(root))
 789                 return root;
 790
 791         root->cache.start = location->objectid;
 792         root->cache.size = 1;
 793         ret = insert_existing_cache_extent(&fs_info->fs_root_cache,
 794                                            &root->cache);
 795         BUG_ON(ret);
 796         return root;
 797 }
 798
 799 void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
 800 {
 801         free(fs_info->tree_root);
 802         free(fs_info->extent_root);
 803         free(fs_info->chunk_root);
 804         free(fs_info->dev_root);
 805         free(fs_info->csum_root);
 806         free(fs_info->super_copy);
 807         free(fs_info->log_root_tree);
 808         free(fs_info);
 809 }
 810
 811 struct btrfs_fs_info *btrfs_new_fs_info(int writable, u64 sb_bytenr)
 812 {
 813         struct btrfs_fs_info *fs_info;
 814
 815         fs_info = malloc(sizeof(struct btrfs_fs_info));
 816         if (!fs_info)
 817                 return NULL;
 818
 819         memset(fs_info, 0, sizeof(struct btrfs_fs_info));
 820
 821         fs_info->tree_root = malloc(sizeof(struct btrfs_root));
 822         fs_info->extent_root = malloc(sizeof(struct btrfs_root));
 823         fs_info->chunk_root = malloc(sizeof(struct btrfs_root));
 824         fs_info->dev_root = malloc(sizeof(struct btrfs_root));
 825         fs_info->csum_root = malloc(sizeof(struct btrfs_root));
 826         fs_info->super_copy = malloc(BTRFS_SUPER_INFO_SIZE);
 827
 828         if (!fs_info->tree_root || !fs_info->extent_root ||
 829             !fs_info->chunk_root || !fs_info->dev_root ||
 830             !fs_info->csum_root || !fs_info->super_copy)
 831                 goto free_all;
 832
 833         memset(fs_info->super_copy, 0, BTRFS_SUPER_INFO_SIZE);
 834         memset(fs_info->tree_root, 0, sizeof(struct btrfs_root));
 835         memset(fs_info->extent_root, 0, sizeof(struct btrfs_root));
 836         memset(fs_info->chunk_root, 0, sizeof(struct btrfs_root));
 837         memset(fs_info->dev_root, 0, sizeof(struct btrfs_root));
 838         memset(fs_info->csum_root, 0, sizeof(struct btrfs_root));
 839
 840         extent_io_tree_init(&fs_info->extent_cache);
 841         extent_io_tree_init(&fs_info->free_space_cache);
 842         extent_io_tree_init(&fs_info->block_group_cache);
 843         extent_io_tree_init(&fs_info->pinned_extents);
 844         extent_io_tree_init(&fs_info->pending_del);
 845         extent_io_tree_init(&fs_info->extent_ins);
 846
 847         cache_tree_init(&fs_info->fs_root_cache);
 848         cache_tree_init(&fs_info->mapping_tree.cache_tree);
 849
 850         mutex_init(&fs_info->fs_mutex);
 851         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
 852         INIT_LIST_HEAD(&fs_info->space_info);
 853
 854         if (!writable)
 855                 fs_info->readonly = 1;
 856
 857         fs_info->super_bytenr = sb_bytenr;
 858         fs_info->data_alloc_profile = (u64)-1;
 859         fs_info->metadata_alloc_profile = (u64)-1;
 860         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
 861         return fs_info;
 862 free_all:
 863         btrfs_free_fs_info(fs_info);
 864         return NULL;
 865 }
 866
 867 int btrfs_check_fs_compatibility(struct btrfs_super_block *sb, int writable)
 868 {
 869         u64 features;
 870
 871         features = btrfs_super_incompat_flags(sb) &
 872                    ~BTRFS_FEATURE_INCOMPAT_SUPP;
 873         if (features) {
 874                 printk("couldn't open because of unsupported "
 875                        "option features (%Lx).\n",
 876                        (unsigned long long)features);
 877                 return -ENOTSUP;
 878         }
 879
 880         features = btrfs_super_incompat_flags(sb);
 881         if (!(features & BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF)) {
 882                 features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
 883                 btrfs_set_super_incompat_flags(sb, features);
 884         }
 885
 886         features = btrfs_super_compat_ro_flags(sb) &
 887                 ~BTRFS_FEATURE_COMPAT_RO_SUPP;
 888         if (writable && features) {
 889                 printk("couldn't open RDWR because of unsupported "
 890                        "option features (%Lx).\n",
 891                        (unsigned long long)features);
 892                 return -ENOTSUP;
 893         }
 894         return 0;
 895 }
 896
 897 int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info,
 898                           u64 root_tree_bytenr, int partial)
 899 {
 900         struct btrfs_super_block *sb = fs_info->super_copy;
 901         struct btrfs_root *root;
 902         struct btrfs_key key;
 903         u32 sectorsize;
 904         u32 nodesize;
 905         u32 leafsize;
 906         u32 stripesize;
 907         u64 generation;
 908         u32 blocksize;
 909         int ret;
 910
 911         nodesize = btrfs_super_nodesize(sb);
 912         leafsize = btrfs_super_leafsize(sb);
 913         sectorsize = btrfs_super_sectorsize(sb);
 914         stripesize = btrfs_super_stripesize(sb);
 915
 916         root = fs_info->tree_root;
 917         __setup_root(nodesize, leafsize, sectorsize, stripesize,
 918                      root, fs_info, BTRFS_ROOT_TREE_OBJECTID);
 919         blocksize = btrfs_level_size(root, btrfs_super_root_level(sb));
 920         generation = btrfs_super_generation(sb);
 921
 922         if (!root_tree_bytenr)
 923                 root_tree_bytenr = btrfs_super_root(sb);
 924         root->node = read_tree_block(root, root_tree_bytenr, blocksize,
 925                                      generation);
 926         if (!extent_buffer_uptodate(root->node)) {
 927                 fprintf(stderr, "Couldn't read tree root\n");
 928                 return -EIO;
 929         }
 930
 931         ret = find_and_setup_root(root, fs_info, BTRFS_EXTENT_TREE_OBJECTID,
 932                                   fs_info->extent_root);
 933         if (ret) {
 934                 printk("Couldn't setup extent tree\n");
 935                 return -EIO;
 936         }
 937         fs_info->extent_root->track_dirty = 1;
 938
 939         ret = find_and_setup_root(root, fs_info, BTRFS_DEV_TREE_OBJECTID,
 940                                   fs_info->dev_root);
 941         if (ret) {
 942                 printk("Couldn't setup device tree\n");
 943                 return -EIO;
 944         }
 945         fs_info->dev_root->track_dirty = 1;
 946
 947         ret = find_and_setup_root(root, fs_info, BTRFS_CSUM_TREE_OBJECTID,
 948                                   fs_info->csum_root);
 949         if (ret) {
 950                 printk("Couldn't setup csum tree\n");
 951                 if (!partial)
 952                         return -EIO;
 953         }
 954         fs_info->csum_root->track_dirty = 1;
 955
 956         ret = find_and_setup_log_root(root, fs_info, sb);
 957         if (ret) {
 958                 printk("Couldn't setup log root tree\n");
 959                 return -EIO;
 960         }
 961
 962         fs_info->generation = generation;
 963         fs_info->last_trans_committed = generation;
 964         btrfs_read_block_groups(fs_info->tree_root);
 965
 966         key.objectid = BTRFS_FS_TREE_OBJECTID;
 967         key.type = BTRFS_ROOT_ITEM_KEY;
 968         key.offset = (u64)-1;
 969         fs_info->fs_root = btrfs_read_fs_root(fs_info, &key);
 970
 971         if (!fs_info->fs_root)
 972                 return -EIO;
 973         return 0;
 974 }
 975
 976 void btrfs_release_all_roots(struct btrfs_fs_info *fs_info)
 977 {
 978         if (fs_info->csum_root)
 979                 free_extent_buffer(fs_info->csum_root->node);
 980         if (fs_info->dev_root)
 981                 free_extent_buffer(fs_info->dev_root->node);
 982         if (fs_info->extent_root)
 983                 free_extent_buffer(fs_info->extent_root->node);
 984         if (fs_info->tree_root)
 985                 free_extent_buffer(fs_info->tree_root->node);
 986         if (fs_info->log_root_tree)
 987                 free_extent_buffer(fs_info->log_root_tree->node);
 988         if (fs_info->chunk_root)
 989                 free_extent_buffer(fs_info->chunk_root->node);
 990 }
 991
 992 static void free_mapping_cache(struct btrfs_fs_info *fs_info)
 993 {
 994         struct cache_tree *cache_tree = &fs_info->mapping_tree.cache_tree;
 995         struct cache_extent *ce;
 996         struct map_lookup *map;
 997
 998         while ((ce = find_first_cache_extent(cache_tree, 0))) {
 999                 map = container_of(ce, struct map_lookup, ce);
1000                 remove_cache_extent(cache_tree, ce);
1001                 kfree(map);
1002         }
1003 }
1004
1005 void btrfs_cleanup_all_caches(struct btrfs_fs_info *fs_info)
1006 {
1007         free_mapping_cache(fs_info);
1008         extent_io_tree_cleanup(&fs_info->extent_cache);
1009         extent_io_tree_cleanup(&fs_info->free_space_cache);
1010         extent_io_tree_cleanup(&fs_info->block_group_cache);
1011         extent_io_tree_cleanup(&fs_info->pinned_extents);
1012         extent_io_tree_cleanup(&fs_info->pending_del);
1013         extent_io_tree_cleanup(&fs_info->extent_ins);
1014 }
1015
1016 int btrfs_scan_fs_devices(int fd, const char *path,
1017                           struct btrfs_fs_devices **fs_devices)
1018 {
1019         u64 total_devs;
1020         int ret;
1021
1022         ret = btrfs_scan_one_device(fd, path, fs_devices,
1023                                     &total_devs, BTRFS_SUPER_INFO_OFFSET);
1024         if (ret) {
1025                 fprintf(stderr, "No valid Btrfs found on %s\n", path);
1026                 return ret;
1027         }
1028
1029         if (total_devs != 1) {
1030                 ret = btrfs_scan_for_fsid(*fs_devices, total_devs, 1);
1031                 if (ret)
1032                         return ret;
1033         }
1034         return 0;
1035 }
1036
1037 int btrfs_setup_chunk_tree_and_device_map(struct btrfs_fs_info *fs_info)
1038 {
1039         struct btrfs_super_block *sb = fs_info->super_copy;
1040         u32 sectorsize;
1041         u32 nodesize;
1042         u32 leafsize;
1043         u32 blocksize;
1044         u32 stripesize;
1045         u64 generation;
1046         int ret;
1047
1048         nodesize = btrfs_super_nodesize(sb);
1049         leafsize = btrfs_super_leafsize(sb);
1050         sectorsize = btrfs_super_sectorsize(sb);
1051         stripesize = btrfs_super_stripesize(sb);
1052
1053         __setup_root(nodesize, leafsize, sectorsize, stripesize,
1054                      fs_info->chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1055
1056         ret = btrfs_read_sys_array(fs_info->chunk_root);
1057         if (ret)
1058                 return ret;
1059
1060         blocksize = btrfs_level_size(fs_info->chunk_root,
1061                                      btrfs_super_chunk_root_level(sb));
1062         generation = btrfs_super_chunk_root_generation(sb);
1063
1064         fs_info->chunk_root->node = read_tree_block(fs_info->chunk_root,
1065                                                     btrfs_super_chunk_root(sb),
1066                                                     blocksize, generation);
1067         if (!fs_info->chunk_root->node ||
1068             !extent_buffer_uptodate(fs_info->chunk_root->node)) {
1069                 fprintf(stderr, "Couldn't read chunk root\n");
1070                 return ret;
1071         }
1072
1073         if (!(btrfs_super_flags(sb) & BTRFS_SUPER_FLAG_METADUMP)) {
1074                 ret = btrfs_read_chunk_tree(fs_info->chunk_root);
1075                 if (ret) {
1076                         fprintf(stderr, "Couldn't read chunk tree\n");
1077                         return ret;
1078                 }
1079         }
1080         return 0;
1081 }
1082
1083 static struct btrfs_fs_info *__open_ctree_fd(int fp, const char *path,
1084                                              u64 sb_bytenr,
1085                                              u64 root_tree_bytenr, int writes,
1086                                              int partial)
1087 {
1088         struct btrfs_fs_info *fs_info;
1089         struct btrfs_super_block *disk_super;
1090         struct btrfs_fs_devices *fs_devices = NULL;
1091         struct extent_buffer *eb;
1092         int ret;
1093
1094         if (sb_bytenr == 0)
1095                 sb_bytenr = BTRFS_SUPER_INFO_OFFSET;
1096
1097         /* try to drop all the caches */
1098         if (posix_fadvise(fp, 0, 0, POSIX_FADV_DONTNEED))
1099                 fprintf(stderr, "Warning, could not drop caches\n");
1100
1101         fs_info = btrfs_new_fs_info(writes, sb_bytenr);
1102         if (!fs_info) {
1103                 fprintf(stderr, "Failed to allocate memory for fs_info\n");
1104                 return NULL;
1105         }
1106
1107         ret = btrfs_scan_fs_devices(fp, path, &fs_devices);
1108         if (ret)
1109                 goto out;
1110
1111         fs_info->fs_devices = fs_devices;
1112         if (writes)
1113                 ret = btrfs_open_devices(fs_devices, O_RDWR);
1114         else
1115                 ret = btrfs_open_devices(fs_devices, O_RDONLY);
1116         if (ret)
1117                 goto out_devices;
1118
1119
1120         disk_super = fs_info->super_copy;
1121         ret = btrfs_read_dev_super(fs_devices->latest_bdev,
1122                                    disk_super, sb_bytenr);
1123         if (ret) {
1124                 printk("No valid btrfs found\n");
1125                 goto out_devices;
1126         }
1127
1128         memcpy(fs_info->fsid, &disk_super->fsid, BTRFS_FSID_SIZE);
1129
1130         ret = btrfs_check_fs_compatibility(fs_info->super_copy, writes);
1131         if (ret)
1132                 goto out_devices;
1133
1134         ret = btrfs_setup_chunk_tree_and_device_map(fs_info);
1135         if (ret)
1136                 goto out_chunk;
1137
1138         eb = fs_info->chunk_root->node;
1139         read_extent_buffer(eb, fs_info->chunk_tree_uuid,
1140                            (unsigned long)btrfs_header_chunk_tree_uuid(eb),
1141                            BTRFS_UUID_SIZE);
1142
1143         ret = btrfs_setup_all_roots(fs_info, root_tree_bytenr, partial);
1144         if (ret)
1145                 goto out_failed;
1146
1147         return fs_info;
1148
1149 out_failed:
1150         if (partial)
1151                 return fs_info;
1152 out_chunk:
1153         btrfs_release_all_roots(fs_info);
1154         btrfs_cleanup_all_caches(fs_info);
1155 out_devices:
1156         btrfs_close_devices(fs_devices);
1157 out:
1158         btrfs_free_fs_info(fs_info);
1159         return NULL;
1160 }
1161
1162 struct btrfs_fs_info *open_ctree_fs_info(const char *filename,
1163                                          u64 sb_bytenr, u64 root_tree_bytenr,
1164                                          int writes, int partial)
1165 {
1166         int fp;
1167         struct btrfs_fs_info *info;
1168         int flags = O_CREAT | O_RDWR;
1169
1170         if (!writes)
1171                 flags = O_RDONLY;
1172
1173         fp = open(filename, flags, 0600);
1174         if (fp < 0) {
1175                 fprintf (stderr, "Could not open %s\n", filename);
1176                 return NULL;
1177         }
1178         info = __open_ctree_fd(fp, filename, sb_bytenr, root_tree_bytenr,
1179                                writes, partial);
1180         close(fp);
1181         return info;
1182 }
1183
1184 struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr, int writes)
1185 {
1186         struct btrfs_fs_info *info;
1187
1188         info = open_ctree_fs_info(filename, sb_bytenr, 0, writes, 0);
1189         if (!info)
1190                 return NULL;
1191         return info->fs_root;
1192 }
1193
1194 struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr,
1195                                  int writes)
1196 {
1197         struct btrfs_fs_info *info;
1198         info = __open_ctree_fd(fp, path, sb_bytenr, 0, writes, 0);
1199         if (!info)
1200                 return NULL;
1201         return info->fs_root;
1202 }
1203
1204 int btrfs_read_dev_super(int fd, struct btrfs_super_block *sb, u64 sb_bytenr)
1205 {
1206         u8 fsid[BTRFS_FSID_SIZE];
1207         int fsid_is_initialized = 0;
1208         struct btrfs_super_block buf;
1209         int i;
1210         int ret;
1211         u64 transid = 0;
1212         u64 bytenr;
1213
1214         if (sb_bytenr != BTRFS_SUPER_INFO_OFFSET) {
1215                 ret = pread64(fd, &buf, sizeof(buf), sb_bytenr);
1216                 if (ret < sizeof(buf))
1217                         return -1;
1218
1219                 if (btrfs_super_bytenr(&buf) != sb_bytenr ||
1220                     buf.magic != cpu_to_le64(BTRFS_MAGIC))
1221                         return -1;
1222
1223                 memcpy(sb, &buf, sizeof(*sb));
1224                 return 0;
1225         }
1226
1227         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1228                 bytenr = btrfs_sb_offset(i);
1229                 ret = pread64(fd, &buf, sizeof(buf), bytenr);
1230                 if (ret < sizeof(buf))
1231                         break;
1232
1233                 if (btrfs_super_bytenr(&buf) != bytenr )
1234                         continue;
1235                 /* if magic is NULL, the device was removed */
1236                 if (buf.magic == 0 && i == 0)
1237                         return -1;
1238                 if (buf.magic != cpu_to_le64(BTRFS_MAGIC))
1239                         continue;
1240
1241                 if (!fsid_is_initialized) {
1242                         memcpy(fsid, buf.fsid, sizeof(fsid));
1243                         fsid_is_initialized = 1;
1244                 } else if (memcmp(fsid, buf.fsid, sizeof(fsid))) {
1245                         /*
1246                          * the superblocks (the original one and
1247                          * its backups) contain data of different
1248                          * filesystems -> the super cannot be trusted
1249                          */
1250                         continue;
1251                 }
1252
1253                 if (btrfs_super_generation(&buf) > transid) {
1254                         memcpy(sb, &buf, sizeof(*sb));
1255                         transid = btrfs_super_generation(&buf);
1256                 }
1257         }
1258
1259         return transid > 0 ? 0 : -1;
1260 }
1261
1262 int write_dev_supers(struct btrfs_root *root, struct btrfs_super_block *sb,
1263                      struct btrfs_device *device)
1264 {
1265         u64 bytenr;
1266         u32 crc;
1267         int i, ret;
1268
1269         if (root->fs_info->super_bytenr != BTRFS_SUPER_INFO_OFFSET) {
1270                 btrfs_set_super_bytenr(sb, root->fs_info->super_bytenr);
1271                 crc = ~(u32)0;
1272                 crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE, crc,
1273                                       BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
1274                 btrfs_csum_final(crc, (char *)&sb->csum[0]);
1275
1276                 /*
1277                  * super_copy is BTRFS_SUPER_INFO_SIZE bytes and is
1278                  * zero filled, we can use it directly
1279                  */
1280                 ret = pwrite64(device->fd, root->fs_info->super_copy,
1281                                 BTRFS_SUPER_INFO_SIZE,
1282                                 root->fs_info->super_bytenr);
1283                 BUG_ON(ret != BTRFS_SUPER_INFO_SIZE);
1284                 return 0;
1285         }
1286
1287         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
1288                 bytenr = btrfs_sb_offset(i);
1289                 if (bytenr + BTRFS_SUPER_INFO_SIZE > device->total_bytes)
1290                         break;
1291
1292                 btrfs_set_super_bytenr(sb, bytenr);
1293
1294                 crc = ~(u32)0;
1295                 crc = btrfs_csum_data(NULL, (char *)sb + BTRFS_CSUM_SIZE, crc,
1296                                       BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
1297                 btrfs_csum_final(crc, (char *)&sb->csum[0]);
1298
1299                 /*
1300                  * super_copy is BTRFS_SUPER_INFO_SIZE bytes and is
1301                  * zero filled, we can use it directly
1302                  */
1303                 ret = pwrite64(device->fd, root->fs_info->super_copy,
1304                                 BTRFS_SUPER_INFO_SIZE, bytenr);
1305                 BUG_ON(ret != BTRFS_SUPER_INFO_SIZE);
1306         }
1307
1308         return 0;
1309 }
1310
1311 int write_all_supers(struct btrfs_root *root)
1312 {
1313         struct list_head *cur;
1314         struct list_head *head = &root->fs_info->fs_devices->devices;
1315         struct btrfs_device *dev;
1316         struct btrfs_super_block *sb;
1317         struct btrfs_dev_item *dev_item;
1318         int ret;
1319         u64 flags;
1320
1321         sb = root->fs_info->super_copy;
1322         dev_item = &sb->dev_item;
1323         list_for_each(cur, head) {
1324                 dev = list_entry(cur, struct btrfs_device, dev_list);
1325                 if (!dev->writeable)
1326                         continue;
1327
1328                 btrfs_set_stack_device_generation(dev_item, 0);
1329                 btrfs_set_stack_device_type(dev_item, dev->type);
1330                 btrfs_set_stack_device_id(dev_item, dev->devid);
1331                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
1332                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
1333                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
1334                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
1335                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
1336                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
1337                 memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
1338
1339                 flags = btrfs_super_flags(sb);
1340                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
1341
1342                 ret = write_dev_supers(root, sb, dev);
1343                 BUG_ON(ret);
1344         }
1345         return 0;
1346 }
1347
1348 int write_ctree_super(struct btrfs_trans_handle *trans,
1349                       struct btrfs_root *root)
1350 {
1351         int ret;
1352         struct btrfs_root *tree_root = root->fs_info->tree_root;
1353         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
1354
1355         if (root->fs_info->readonly)
1356                 return 0;
1357
1358         btrfs_set_super_generation(root->fs_info->super_copy,
1359                                    trans->transid);
1360         btrfs_set_super_root(root->fs_info->super_copy,
1361                              tree_root->node->start);
1362         btrfs_set_super_root_level(root->fs_info->super_copy,
1363                                    btrfs_header_level(tree_root->node));
1364         btrfs_set_super_chunk_root(root->fs_info->super_copy,
1365                                    chunk_root->node->start);
1366         btrfs_set_super_chunk_root_level(root->fs_info->super_copy,
1367                                          btrfs_header_level(chunk_root->node));
1368         btrfs_set_super_chunk_root_generation(root->fs_info->super_copy,
1369                                 btrfs_header_generation(chunk_root->node));
1370
1371         ret = write_all_supers(root);
1372         if (ret)
1373                 fprintf(stderr, "failed to write new super block err %d\n", ret);
1374         return ret;
1375 }
1376
1377 int close_ctree(struct btrfs_root *root)
1378 {
1379         int ret;
1380         struct btrfs_trans_handle *trans;
1381         struct btrfs_fs_info *fs_info = root->fs_info;
1382
1383         if (fs_info->last_trans_committed !=
1384             fs_info->generation) {
1385                 trans = btrfs_start_transaction(root, 1);
1386                 btrfs_commit_transaction(trans, root);
1387                 trans = btrfs_start_transaction(root, 1);
1388                 ret = commit_tree_roots(trans, fs_info);
1389                 BUG_ON(ret);
1390                 ret = __commit_transaction(trans, root);
1391                 BUG_ON(ret);
1392                 write_ctree_super(trans, root);
1393                 btrfs_free_transaction(root, trans);
1394         }
1395         btrfs_free_block_groups(fs_info);
1396
1397         free_fs_roots(fs_info);
1398
1399         btrfs_release_all_roots(fs_info);
1400         btrfs_close_devices(fs_info->fs_devices);
1401         btrfs_cleanup_all_caches(fs_info);
1402         btrfs_free_fs_info(fs_info);
1403         return 0;
1404 }
1405
1406 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1407                      struct extent_buffer *eb)
1408 {
1409         return clear_extent_buffer_dirty(eb);
1410 }
1411
1412 int wait_on_tree_block_writeback(struct btrfs_root *root,
1413                                  struct extent_buffer *eb)
1414 {
1415         return 0;
1416 }
1417
1418 void btrfs_mark_buffer_dirty(struct extent_buffer *eb)
1419 {
1420         set_extent_buffer_dirty(eb);
1421 }
1422
1423 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
1424 {
1425         int ret;
1426
1427         ret = extent_buffer_uptodate(buf);
1428         if (!ret)
1429                 return ret;
1430
1431         ret = verify_parent_transid(buf->tree, buf, parent_transid, 1);
1432         return !ret;
1433 }
1434
1435 int btrfs_set_buffer_uptodate(struct extent_buffer *eb)
1436 {
1437         return set_extent_buffer_uptodate(eb);
1438 }