disk-io.c

   1 #define _XOPEN_SOURCE 500
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <sys/types.h>
   5 #include <sys/stat.h>
   6 #include <fcntl.h>
   7 #include <unistd.h>
   8 #include "kerncompat.h"
   9 #include "radix-tree.h"
  10 #include "ctree.h"
  11 #include "disk-io.h"
  12 #include "transaction.h"
  13
  14 static int allocated_blocks = 0;
  15 int cache_max = 10000;
  16
  17 struct dev_lookup {
  18         u64 block_start;
  19         u64 num_blocks;
  20         u64 device_id;
  21         int fd;
  22 };
  23
  24 int btrfs_insert_dev_radix(struct btrfs_root *root,
  25                            int fd,
  26                            u64 device_id,
  27                            u64 block_start,
  28                            u64 num_blocks)
  29 {
  30         struct dev_lookup *lookup;
  31         int ret;
  32
  33         lookup = malloc(sizeof(*lookup));
  34         if (!lookup)
  35                 return -ENOMEM;
  36         lookup->block_start = block_start;
  37         lookup->num_blocks = num_blocks;
  38         lookup->fd = fd;
  39         lookup->device_id = device_id;
  40 printf("inserting into dev radix %Lu %Lu\n", block_start, num_blocks);
  41
  42         ret = radix_tree_insert(&root->fs_info->dev_radix, block_start +
  43                                 num_blocks - 1, lookup);
  44         return ret;
  45 }
  46
  47 int btrfs_map_bh_to_logical(struct btrfs_root *root, struct btrfs_buffer *bh,
  48                              u64 logical)
  49 {
  50         struct dev_lookup *lookup[2];
  51
  52         int ret;
  53
  54         root = root->fs_info->dev_root;
  55         ret = radix_tree_gang_lookup(&root->fs_info->dev_radix,
  56                                      (void **)lookup,
  57                                      (unsigned long)logical,
  58                                      ARRAY_SIZE(lookup));
  59         if (ret == 0 || lookup[0]->block_start > logical ||
  60             lookup[0]->block_start + lookup[0]->num_blocks <= logical) {
  61                 ret = -1;
  62                 goto out;
  63         }
  64         bh->fd = lookup[0]->fd;
  65         bh->dev_blocknr = logical - lookup[0]->block_start;
  66         ret = 0;
  67 out:
  68         return ret;
  69 }
  70
  71 static int check_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
  72 {
  73         if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
  74                 BUG();
  75         if (memcmp(root->fs_info->disk_super->fsid, buf->node.header.fsid,
  76                    sizeof(buf->node.header.fsid)))
  77                 BUG();
  78         return 0;
  79 }
  80
  81 static int free_some_buffers(struct btrfs_root *root)
  82 {
  83         struct list_head *node, *next;
  84         struct btrfs_buffer *b;
  85         if (root->fs_info->cache_size < cache_max)
  86                 return 0;
  87         list_for_each_safe(node, next, &root->fs_info->cache) {
  88                 b = list_entry(node, struct btrfs_buffer, cache);
  89                 if (b->count == 1) {
  90                         BUG_ON(!list_empty(&b->dirty));
  91                         list_del_init(&b->cache);
  92                         btrfs_block_release(root, b);
  93                         if (root->fs_info->cache_size < cache_max)
  94                                 break;
  95                 }
  96         }
  97         return 0;
  98 }
  99
 100 struct btrfs_buffer *alloc_tree_block(struct btrfs_root *root, u64 blocknr)
 101 {
 102         struct btrfs_buffer *buf;
 103         int ret;
 104
 105         buf = malloc(sizeof(struct btrfs_buffer) + root->blocksize);
 106         if (!buf)
 107                 return buf;
 108         allocated_blocks++;
 109         buf->blocknr = blocknr;
 110         buf->count = 2;
 111         INIT_LIST_HEAD(&buf->dirty);
 112         free_some_buffers(root);
 113         radix_tree_preload(GFP_KERNEL);
 114         ret = radix_tree_insert(&root->fs_info->cache_radix, blocknr, buf);
 115         radix_tree_preload_end();
 116         list_add_tail(&buf->cache, &root->fs_info->cache);
 117         root->fs_info->cache_size++;
 118         if (ret) {
 119                 free(buf);
 120                 return NULL;
 121         }
 122         return buf;
 123 }
 124
 125 struct btrfs_buffer *find_tree_block(struct btrfs_root *root, u64 blocknr)
 126 {
 127         struct btrfs_buffer *buf;
 128         buf = radix_tree_lookup(&root->fs_info->cache_radix, blocknr);
 129         if (buf) {
 130                 buf->count++;
 131         } else {
 132                 buf = alloc_tree_block(root, blocknr);
 133                 if (!buf) {
 134                         BUG();
 135                         return NULL;
 136                 }
 137         }
 138         return buf;
 139 }
 140
 141 struct btrfs_buffer *read_tree_block(struct btrfs_root *root, u64 blocknr)
 142 {
 143         struct btrfs_buffer *buf;
 144         int ret;
 145         buf = radix_tree_lookup(&root->fs_info->cache_radix, blocknr);
 146         if (buf) {
 147                 buf->count++;
 148         } else {
 149                 buf = alloc_tree_block(root, blocknr);
 150                 if (!buf)
 151                         return NULL;
 152                 btrfs_map_bh_to_logical(root, buf, blocknr);
 153                 ret = pread(buf->fd, &buf->node, root->blocksize,
 154                             buf->dev_blocknr * root->blocksize);
 155                 if (ret != root->blocksize) {
 156                         free(buf);
 157                         return NULL;
 158                 }
 159         }
 160         if (check_tree_block(root, buf))
 161                 BUG();
 162         return buf;
 163 }
 164
 165 int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 166                      struct btrfs_buffer *buf)
 167 {
 168         if (!list_empty(&buf->dirty))
 169                 return 0;
 170         list_add_tail(&buf->dirty, &root->fs_info->trans);
 171         buf->count++;
 172         return 0;
 173 }
 174
 175 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 176                      struct btrfs_buffer *buf)
 177 {
 178         if (!list_empty(&buf->dirty)) {
 179                 list_del_init(&buf->dirty);
 180                 btrfs_block_release(root, buf);
 181         }
 182         return 0;
 183 }
 184
 185 int write_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 186                      struct btrfs_buffer *buf)
 187 {
 188         int ret;
 189
 190         if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
 191                 BUG();
 192         btrfs_map_bh_to_logical(root, buf, buf->blocknr);
 193         ret = pwrite(buf->fd, &buf->node, root->blocksize,
 194                      buf->dev_blocknr * root->blocksize);
 195         if (ret != root->blocksize)
 196                 return ret;
 197         return 0;
 198 }
 199
 200 static int __commit_transaction(struct btrfs_trans_handle *trans, struct
 201                                 btrfs_root *root)
 202 {
 203         struct btrfs_buffer *b;
 204         int ret = 0;
 205         int wret;
 206         while(!list_empty(&root->fs_info->trans)) {
 207                 b = list_entry(root->fs_info->trans.next, struct btrfs_buffer,
 208                                dirty);
 209                 list_del_init(&b->dirty);
 210                 wret = write_tree_block(trans, root, b);
 211                 if (wret)
 212                         ret = wret;
 213                 btrfs_block_release(root, b);
 214         }
 215         return ret;
 216 }
 217
 218 static int commit_tree_roots(struct btrfs_trans_handle *trans,
 219                              struct btrfs_fs_info *fs_info)
 220 {
 221         int ret;
 222         u64 old_extent_block;
 223         struct btrfs_root *tree_root = fs_info->tree_root;
 224         struct btrfs_root *extent_root = fs_info->extent_root;
 225
 226         if (btrfs_super_device_root(fs_info->disk_super) !=
 227             fs_info->dev_root->node->blocknr) {
 228                 btrfs_set_super_device_root(fs_info->disk_super,
 229                                             fs_info->dev_root->node->blocknr);
 230         }
 231         while(1) {
 232                 old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
 233                 if (old_extent_block == extent_root->node->blocknr)
 234                         break;
 235                 btrfs_set_root_blocknr(&extent_root->root_item,
 236                                        extent_root->node->blocknr);
 237                 ret = btrfs_update_root(trans, tree_root,
 238                                         &extent_root->root_key,
 239                                         &extent_root->root_item);
 240                 BUG_ON(ret);
 241         }
 242         return 0;
 243 }
 244
 245 int btrfs_commit_transaction(struct btrfs_trans_handle *trans, struct
 246                              btrfs_root *root, struct btrfs_super_block *s)
 247 {
 248         int ret = 0;
 249         struct btrfs_buffer *snap = root->commit_root;
 250         struct btrfs_key snap_key;
 251
 252         if (root->commit_root == root->node)
 253                 return 0;
 254
 255         memcpy(&snap_key, &root->root_key, sizeof(snap_key));
 256         root->root_key.offset++;
 257
 258         btrfs_set_root_blocknr(&root->root_item, root->node->blocknr);
 259         ret = btrfs_insert_root(trans, root->fs_info->tree_root,
 260                                 &root->root_key, &root->root_item);
 261         BUG_ON(ret);
 262
 263         ret = commit_tree_roots(trans, root->fs_info);
 264         BUG_ON(ret);
 265
 266         ret = __commit_transaction(trans, root);
 267         BUG_ON(ret);
 268
 269         write_ctree_super(trans, root, s);
 270         btrfs_finish_extent_commit(trans, root->fs_info->extent_root);
 271         btrfs_finish_extent_commit(trans, root->fs_info->tree_root);
 272
 273         root->commit_root = root->node;
 274         root->node->count++;
 275         ret = btrfs_drop_snapshot(trans, root, snap);
 276         BUG_ON(ret);
 277
 278         ret = btrfs_del_root(trans, root->fs_info->tree_root, &snap_key);
 279         BUG_ON(ret);
 280         root->fs_info->generation = root->root_key.offset + 1;
 281
 282         return ret;
 283 }
 284
 285 static int __setup_root(struct btrfs_super_block *super,
 286                         struct btrfs_root *root,
 287                         struct btrfs_fs_info *fs_info,
 288                         u64 objectid, int fp)
 289 {
 290         root->node = NULL;
 291         root->commit_root = NULL;
 292         root->blocksize = btrfs_super_blocksize(super);
 293         root->ref_cows = 0;
 294         root->fs_info = fs_info;
 295         memset(&root->root_key, 0, sizeof(root->root_key));
 296         memset(&root->root_item, 0, sizeof(root->root_item));
 297         return 0;
 298 }
 299
 300 static int find_and_setup_root(struct btrfs_super_block *super,
 301                                struct btrfs_root *tree_root,
 302                                struct btrfs_fs_info *fs_info,
 303                                u64 objectid,
 304                                struct btrfs_root *root, int fp)
 305 {
 306         int ret;
 307
 308         __setup_root(super, root, fs_info, objectid, fp);
 309         ret = btrfs_find_last_root(tree_root, objectid,
 310                                    &root->root_item, &root->root_key);
 311         BUG_ON(ret);
 312
 313         root->node = read_tree_block(root,
 314                                      btrfs_root_blocknr(&root->root_item));
 315         BUG_ON(!root->node);
 316         return 0;
 317 }
 318
 319 int btrfs_open_disk(struct btrfs_root *root, u64 device_id,
 320                     u64 block_start, u64 num_blocks,
 321                     char *filename, int name_len)
 322 {
 323         char *null_filename;
 324         int fd;
 325         int ret;
 326
 327         null_filename = malloc(name_len + 1);
 328         if (!null_filename)
 329                 return -ENOMEM;
 330         memcpy(null_filename, filename, name_len);
 331         null_filename[name_len] = '\0';
 332
 333         fd = open(null_filename, O_RDWR);
 334         if (fd < 0) {
 335                 ret = -1;
 336                 goto out;
 337         }
 338         ret = btrfs_insert_dev_radix(root, fd, device_id,
 339                                      block_start, num_blocks);
 340         BUG_ON(ret);
 341         ret = 0;
 342 out:
 343         free(null_filename);
 344         return ret;
 345 }
 346
 347 static int read_device_info(struct btrfs_root *root)
 348 {
 349         struct btrfs_path path;
 350         int ret;
 351         struct btrfs_key key;
 352         struct btrfs_leaf *leaf;
 353         struct btrfs_device_item *dev_item;
 354         int nritems;
 355         int slot;
 356
 357         root = root->fs_info->dev_root;
 358
 359         btrfs_init_path(&path);
 360         key.objectid = 0;
 361         key.offset = 0;
 362         key.flags = 0;
 363         btrfs_set_key_type(&key, BTRFS_DEV_ITEM_KEY);
 364
 365         ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
 366         leaf = &path.nodes[0]->leaf;
 367         nritems = btrfs_header_nritems(&leaf->header);
 368         while(1) {
 369                 slot = path.slots[0];
 370                 if (slot >= nritems) {
 371                         ret = btrfs_next_leaf(root, &path);
 372                         if (ret)
 373                                 break;
 374                         leaf = &path.nodes[0]->leaf;
 375                         nritems = btrfs_header_nritems(&leaf->header);
 376                         slot = path.slots[0];
 377                 }
 378                 btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
 379                 if (btrfs_key_type(&key) != BTRFS_DEV_ITEM_KEY) {
 380                         path.slots[0]++;
 381                         continue;
 382                 }
 383                 dev_item = btrfs_item_ptr(leaf, slot, struct btrfs_device_item);
 384                 if (btrfs_device_id(dev_item) !=
 385                     btrfs_super_device_id(root->fs_info->disk_super)) {
 386 printf("found key %Lu %Lu\n", key.objectid, key.offset);
 387                         ret = btrfs_open_disk(root, btrfs_device_id(dev_item),
 388                                               key.objectid, key.offset,
 389                                               (char *)(dev_item + 1),
 390                                               btrfs_device_pathlen(dev_item));
 391                         BUG_ON(ret);
 392                 }
 393                 path.slots[0]++;
 394         }
 395         btrfs_release_path(root, &path);
 396         return 0;
 397 }
 398
 399 struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super)
 400 {
 401         int fp;
 402
 403         fp = open(filename, O_CREAT | O_RDWR, 0600);
 404         if (fp < 0) {
 405                 return NULL;
 406         }
 407         return open_ctree_fd(fp, super);
 408 }
 409
 410 struct btrfs_root *open_ctree_fd(int fp, struct btrfs_super_block *super)
 411 {
 412         struct btrfs_root *root = malloc(sizeof(struct btrfs_root));
 413         struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
 414         struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
 415         struct btrfs_root *dev_root = malloc(sizeof(struct btrfs_root));
 416         struct btrfs_fs_info *fs_info = malloc(sizeof(*fs_info));
 417         struct dev_lookup *dev_lookup;
 418         int ret;
 419
 420         INIT_RADIX_TREE(&fs_info->cache_radix, GFP_KERNEL);
 421         INIT_RADIX_TREE(&fs_info->pinned_radix, GFP_KERNEL);
 422         INIT_RADIX_TREE(&fs_info->dev_radix, GFP_KERNEL);
 423         INIT_LIST_HEAD(&fs_info->trans);
 424         INIT_LIST_HEAD(&fs_info->cache);
 425         fs_info->cache_size = 0;
 426         fs_info->fp = fp;
 427         fs_info->running_transaction = NULL;
 428         fs_info->fs_root = root;
 429         fs_info->tree_root = tree_root;
 430         fs_info->extent_root = extent_root;
 431         fs_info->dev_root = dev_root;
 432         fs_info->last_inode_alloc = 0;
 433         fs_info->last_inode_alloc_dirid = 0;
 434         fs_info->disk_super = super;
 435         memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
 436         memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
 437
 438         ret = pread(fp, super, sizeof(struct btrfs_super_block),
 439                      BTRFS_SUPER_INFO_OFFSET);
 440         if (ret == 0 || btrfs_super_root(super) == 0) {
 441                 BUG();
 442                 return NULL;
 443         }
 444         BUG_ON(ret < 0);
 445         __setup_root(super, dev_root, fs_info, BTRFS_DEV_TREE_OBJECTID, fp);
 446
 447         dev_lookup = malloc(sizeof(*dev_lookup));
 448         dev_lookup->fd = fp;
 449         dev_lookup->device_id = btrfs_super_device_id(super);
 450         dev_lookup->block_start = btrfs_super_device_block_start(super);
 451         dev_lookup->num_blocks = btrfs_super_device_num_blocks(super);
 452         ret = radix_tree_insert(&fs_info->dev_radix,
 453                                 dev_lookup->block_start +
 454                                 dev_lookup->num_blocks - 1, dev_lookup);
 455         BUG_ON(ret);
 456
 457         dev_root->node = read_tree_block(dev_root,
 458                                          btrfs_super_device_root(super));
 459
 460         ret = read_device_info(dev_root);
 461         BUG_ON(ret);
 462
 463         __setup_root(super, tree_root, fs_info, BTRFS_ROOT_TREE_OBJECTID, fp);
 464         tree_root->node = read_tree_block(tree_root, btrfs_super_root(super));
 465         BUG_ON(!tree_root->node);
 466
 467         ret = find_and_setup_root(super, tree_root, fs_info,
 468                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root, fp);
 469         BUG_ON(ret);
 470
 471         ret = find_and_setup_root(super, tree_root, fs_info,
 472                                   BTRFS_FS_TREE_OBJECTID, root, fp);
 473         BUG_ON(ret);
 474
 475         root->commit_root = root->node;
 476         root->node->count++;
 477         root->ref_cows = 1;
 478         root->fs_info->generation = root->root_key.offset + 1;
 479         return root;
 480 }
 481
 482 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
 483                       *root, struct btrfs_super_block *s)
 484 {
 485         int ret;
 486         btrfs_set_super_root(s, root->fs_info->tree_root->node->blocknr);
 487         ret = pwrite(root->fs_info->fp, s, sizeof(*s),
 488                      BTRFS_SUPER_INFO_OFFSET);
 489         if (ret != sizeof(*s)) {
 490                 fprintf(stderr, "failed to write new super block err %d\n", ret);
 491                 return ret;
 492         }
 493         return 0;
 494 }
 495
 496 static int drop_cache(struct btrfs_root *root)
 497 {
 498         while(!list_empty(&root->fs_info->cache)) {
 499                 struct btrfs_buffer *b = list_entry(root->fs_info->cache.next,
 500                                                     struct btrfs_buffer,
 501                                                     cache);
 502                 list_del_init(&b->cache);
 503                 btrfs_block_release(root, b);
 504         }
 505         return 0;
 506 }
 507
 508 static int free_dev_radix(struct btrfs_fs_info *fs_info)
 509 {
 510         struct dev_lookup *lookup[8];
 511         int ret;
 512         int i;
 513         while(1) {
 514                 ret = radix_tree_gang_lookup(&fs_info->dev_radix,
 515                                              (void **)lookup, 0,
 516                                              ARRAY_SIZE(lookup));
 517                 if (!ret)
 518                         break;
 519                 for (i = 0; i < ret; i++) {
 520                         if (lookup[i]->device_id !=
 521                             btrfs_super_device_id(fs_info->disk_super))
 522                                 close(lookup[i]->fd);
 523                         radix_tree_delete(&fs_info->dev_radix,
 524                                           lookup[i]->block_start +
 525                                           lookup[i]->num_blocks - 1);
 526                         free(lookup[i]);
 527                 }
 528         }
 529         return 0;
 530 }
 531
 532 int close_ctree(struct btrfs_root *root, struct btrfs_super_block *s)
 533 {
 534         int ret;
 535         struct btrfs_trans_handle *trans;
 536
 537         trans = root->fs_info->running_transaction;
 538         btrfs_commit_transaction(trans, root, s);
 539         ret = commit_tree_roots(trans, root->fs_info);
 540         BUG_ON(ret);
 541         ret = __commit_transaction(trans, root);
 542         BUG_ON(ret);
 543         write_ctree_super(trans, root, s);
 544         drop_cache(root);
 545         BUG_ON(!list_empty(&root->fs_info->trans));
 546
 547         free_dev_radix(root->fs_info);
 548         close(root->fs_info->fp);
 549         if (root->node)
 550                 btrfs_block_release(root, root->node);
 551         if (root->fs_info->extent_root->node)
 552                 btrfs_block_release(root->fs_info->extent_root,
 553                                     root->fs_info->extent_root->node);
 554         if (root->fs_info->tree_root->node)
 555                 btrfs_block_release(root->fs_info->tree_root,
 556                                     root->fs_info->tree_root->node);
 557         if (root->fs_info->dev_root->node)
 558                 btrfs_block_release(root->fs_info->dev_root,
 559                                     root->fs_info->dev_root->node);
 560         btrfs_block_release(root, root->commit_root);
 561         free(root);
 562         printf("on close %d blocks are allocated\n", allocated_blocks);
 563         return 0;
 564 }
 565
 566 void btrfs_block_release(struct btrfs_root *root, struct btrfs_buffer *buf)
 567 {
 568         buf->count--;
 569         if (buf->count < 0)
 570                 BUG();
 571         if (buf->count == 0) {
 572                 BUG_ON(!list_empty(&buf->cache));
 573                 BUG_ON(!list_empty(&buf->dirty));
 574                 if (!radix_tree_lookup(&root->fs_info->cache_radix,
 575                                        buf->blocknr))
 576                         BUG();
 577                 radix_tree_delete(&root->fs_info->cache_radix, buf->blocknr);
 578                 memset(buf, 0, sizeof(*buf));
 579                 free(buf);
 580                 BUG_ON(allocated_blocks == 0);
 581                 allocated_blocks--;
 582                 BUG_ON(root->fs_info->cache_size == 0);
 583                 root->fs_info->cache_size--;
 584         }
 585 }
 586