disk-io.c

   1 #define _XOPEN_SOURCE 600
   2 #define __USE_XOPEN2K
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <sys/types.h>
   6 #include <sys/stat.h>
   7 #include <fcntl.h>
   8 #include <unistd.h>
   9 #include "kerncompat.h"
  10 #include "radix-tree.h"
  11 #include "ctree.h"
  12 #include "disk-io.h"
  13 #include "transaction.h"
  14
  15 static int allocated_blocks = 0;
  16 int cache_max = 10000;
  17
  18 struct dev_lookup {
  19         u64 block_start;
  20         u64 num_blocks;
  21         u64 device_id;
  22         int fd;
  23 };
  24
  25 int btrfs_insert_dev_radix(struct btrfs_root *root,
  26                            int fd,
  27                            u64 device_id,
  28                            u64 block_start,
  29                            u64 num_blocks)
  30 {
  31         struct dev_lookup *lookup;
  32         int ret;
  33
  34         lookup = malloc(sizeof(*lookup));
  35         if (!lookup)
  36                 return -ENOMEM;
  37         lookup->block_start = block_start;
  38         lookup->num_blocks = num_blocks;
  39         lookup->fd = fd;
  40         lookup->device_id = device_id;
  41 printf("inserting into dev radix %Lu %Lu\n", block_start, num_blocks);
  42
  43         ret = radix_tree_insert(&root->fs_info->dev_radix, block_start +
  44                                 num_blocks - 1, lookup);
  45         return ret;
  46 }
  47
  48 int btrfs_map_bh_to_logical(struct btrfs_root *root, struct btrfs_buffer *bh,
  49                              u64 logical)
  50 {
  51         struct dev_lookup *lookup[2];
  52
  53         int ret;
  54
  55         root = root->fs_info->dev_root;
  56         ret = radix_tree_gang_lookup(&root->fs_info->dev_radix,
  57                                      (void **)lookup,
  58                                      (unsigned long)logical,
  59                                      ARRAY_SIZE(lookup));
  60         if (ret == 0 || lookup[0]->block_start > logical ||
  61             lookup[0]->block_start + lookup[0]->num_blocks <= logical) {
  62                 ret = -1;
  63                 goto out;
  64         }
  65         bh->fd = lookup[0]->fd;
  66         bh->dev_blocknr = logical - lookup[0]->block_start;
  67         ret = 0;
  68 out:
  69         return ret;
  70 }
  71
  72 static int check_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
  73 {
  74         if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
  75                 BUG();
  76         if (memcmp(root->fs_info->disk_super->fsid, buf->node.header.fsid,
  77                    sizeof(buf->node.header.fsid)))
  78                 BUG();
  79         return 0;
  80 }
  81
  82 static int free_some_buffers(struct btrfs_root *root)
  83 {
  84         struct list_head *node, *next;
  85         struct btrfs_buffer *b;
  86         if (root->fs_info->cache_size < cache_max)
  87                 return 0;
  88         list_for_each_safe(node, next, &root->fs_info->cache) {
  89                 b = list_entry(node, struct btrfs_buffer, cache);
  90                 if (b->count == 1) {
  91                         BUG_ON(!list_empty(&b->dirty));
  92                         list_del_init(&b->cache);
  93                         btrfs_block_release(root, b);
  94                         if (root->fs_info->cache_size < cache_max)
  95                                 break;
  96                 }
  97         }
  98         return 0;
  99 }
 100
 101 struct btrfs_buffer *alloc_tree_block(struct btrfs_root *root, u64 blocknr)
 102 {
 103         struct btrfs_buffer *buf;
 104         int ret;
 105
 106         buf = malloc(sizeof(struct btrfs_buffer) + root->blocksize);
 107         if (!buf)
 108                 return buf;
 109         allocated_blocks++;
 110         buf->blocknr = blocknr;
 111         buf->count = 2;
 112         INIT_LIST_HEAD(&buf->dirty);
 113         free_some_buffers(root);
 114         radix_tree_preload(GFP_KERNEL);
 115         ret = radix_tree_insert(&root->fs_info->cache_radix, blocknr, buf);
 116         radix_tree_preload_end();
 117         list_add_tail(&buf->cache, &root->fs_info->cache);
 118         root->fs_info->cache_size++;
 119         if (ret) {
 120                 free(buf);
 121                 return NULL;
 122         }
 123         return buf;
 124 }
 125
 126 struct btrfs_buffer *find_tree_block(struct btrfs_root *root, u64 blocknr)
 127 {
 128         struct btrfs_buffer *buf;
 129         buf = radix_tree_lookup(&root->fs_info->cache_radix, blocknr);
 130         if (buf) {
 131                 buf->count++;
 132         } else {
 133                 buf = alloc_tree_block(root, blocknr);
 134                 if (!buf) {
 135                         BUG();
 136                         return NULL;
 137                 }
 138         }
 139         return buf;
 140 }
 141
 142 struct btrfs_buffer *read_tree_block(struct btrfs_root *root, u64 blocknr)
 143 {
 144         struct btrfs_buffer *buf;
 145         int ret;
 146         buf = radix_tree_lookup(&root->fs_info->cache_radix, blocknr);
 147         if (buf) {
 148                 buf->count++;
 149         } else {
 150                 buf = alloc_tree_block(root, blocknr);
 151                 if (!buf)
 152                         return NULL;
 153                 btrfs_map_bh_to_logical(root, buf, blocknr);
 154                 ret = pread(buf->fd, &buf->node, root->blocksize,
 155                             buf->dev_blocknr * root->blocksize);
 156                 if (ret != root->blocksize) {
 157                         free(buf);
 158                         return NULL;
 159                 }
 160         }
 161         if (check_tree_block(root, buf))
 162                 BUG();
 163         return buf;
 164 }
 165
 166 int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 167                      struct btrfs_buffer *buf)
 168 {
 169         if (!list_empty(&buf->dirty))
 170                 return 0;
 171         list_add_tail(&buf->dirty, &root->fs_info->trans);
 172         buf->count++;
 173         return 0;
 174 }
 175
 176 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 177                      struct btrfs_buffer *buf)
 178 {
 179         if (!list_empty(&buf->dirty)) {
 180                 list_del_init(&buf->dirty);
 181                 btrfs_block_release(root, buf);
 182         }
 183         return 0;
 184 }
 185
 186 int write_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 187                      struct btrfs_buffer *buf)
 188 {
 189         int ret;
 190
 191         if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
 192                 BUG();
 193         btrfs_map_bh_to_logical(root, buf, buf->blocknr);
 194         ret = pwrite(buf->fd, &buf->node, root->blocksize,
 195                      buf->dev_blocknr * root->blocksize);
 196         if (ret != root->blocksize)
 197                 return ret;
 198         return 0;
 199 }
 200
 201 static int __commit_transaction(struct btrfs_trans_handle *trans, struct
 202                                 btrfs_root *root)
 203 {
 204         struct btrfs_buffer *b;
 205         int ret = 0;
 206         int wret;
 207         while(!list_empty(&root->fs_info->trans)) {
 208                 b = list_entry(root->fs_info->trans.next, struct btrfs_buffer,
 209                                dirty);
 210                 list_del_init(&b->dirty);
 211                 wret = write_tree_block(trans, root, b);
 212                 if (wret)
 213                         ret = wret;
 214                 btrfs_block_release(root, b);
 215         }
 216         return ret;
 217 }
 218
 219 static int commit_tree_roots(struct btrfs_trans_handle *trans,
 220                              struct btrfs_fs_info *fs_info)
 221 {
 222         int ret;
 223         u64 old_extent_block;
 224         struct btrfs_root *tree_root = fs_info->tree_root;
 225         struct btrfs_root *extent_root = fs_info->extent_root;
 226
 227         if (btrfs_super_device_root(fs_info->disk_super) !=
 228             fs_info->dev_root->node->blocknr) {
 229                 btrfs_set_super_device_root(fs_info->disk_super,
 230                                             fs_info->dev_root->node->blocknr);
 231         }
 232         while(1) {
 233                 old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
 234                 if (old_extent_block == extent_root->node->blocknr)
 235                         break;
 236                 btrfs_set_root_blocknr(&extent_root->root_item,
 237                                        extent_root->node->blocknr);
 238                 ret = btrfs_update_root(trans, tree_root,
 239                                         &extent_root->root_key,
 240                                         &extent_root->root_item);
 241                 BUG_ON(ret);
 242         }
 243         return 0;
 244 }
 245
 246 int btrfs_commit_transaction(struct btrfs_trans_handle *trans, struct
 247                              btrfs_root *root, struct btrfs_super_block *s)
 248 {
 249         int ret = 0;
 250         struct btrfs_buffer *snap = root->commit_root;
 251         struct btrfs_key snap_key;
 252
 253         if (root->commit_root == root->node)
 254                 return 0;
 255
 256         memcpy(&snap_key, &root->root_key, sizeof(snap_key));
 257         root->root_key.offset++;
 258
 259         btrfs_set_root_blocknr(&root->root_item, root->node->blocknr);
 260         ret = btrfs_insert_root(trans, root->fs_info->tree_root,
 261                                 &root->root_key, &root->root_item);
 262         BUG_ON(ret);
 263
 264         ret = commit_tree_roots(trans, root->fs_info);
 265         BUG_ON(ret);
 266
 267         ret = __commit_transaction(trans, root);
 268         BUG_ON(ret);
 269
 270         write_ctree_super(trans, root, s);
 271         btrfs_finish_extent_commit(trans, root->fs_info->extent_root);
 272         btrfs_finish_extent_commit(trans, root->fs_info->tree_root);
 273
 274         root->commit_root = root->node;
 275         root->node->count++;
 276         ret = btrfs_drop_snapshot(trans, root, snap);
 277         BUG_ON(ret);
 278
 279         ret = btrfs_del_root(trans, root->fs_info->tree_root, &snap_key);
 280         BUG_ON(ret);
 281         root->fs_info->generation = root->root_key.offset + 1;
 282
 283         return ret;
 284 }
 285
 286 static int __setup_root(struct btrfs_super_block *super,
 287                         struct btrfs_root *root,
 288                         struct btrfs_fs_info *fs_info,
 289                         u64 objectid, int fp)
 290 {
 291         root->node = NULL;
 292         root->commit_root = NULL;
 293         root->blocksize = btrfs_super_blocksize(super);
 294         root->ref_cows = 0;
 295         root->fs_info = fs_info;
 296         memset(&root->root_key, 0, sizeof(root->root_key));
 297         memset(&root->root_item, 0, sizeof(root->root_item));
 298         root->root_key.objectid = objectid;
 299         return 0;
 300 }
 301
 302 static int find_and_setup_root(struct btrfs_super_block *super,
 303                                struct btrfs_root *tree_root,
 304                                struct btrfs_fs_info *fs_info,
 305                                u64 objectid,
 306                                struct btrfs_root *root, int fp)
 307 {
 308         int ret;
 309
 310         __setup_root(super, root, fs_info, objectid, fp);
 311         ret = btrfs_find_last_root(tree_root, objectid,
 312                                    &root->root_item, &root->root_key);
 313         BUG_ON(ret);
 314
 315         root->node = read_tree_block(root,
 316                                      btrfs_root_blocknr(&root->root_item));
 317         BUG_ON(!root->node);
 318         return 0;
 319 }
 320
 321 int btrfs_open_disk(struct btrfs_root *root, u64 device_id,
 322                     u64 block_start, u64 num_blocks,
 323                     char *filename, int name_len)
 324 {
 325         char *null_filename;
 326         int fd;
 327         int ret;
 328
 329         null_filename = malloc(name_len + 1);
 330         if (!null_filename)
 331                 return -ENOMEM;
 332         memcpy(null_filename, filename, name_len);
 333         null_filename[name_len] = '\0';
 334
 335         fd = open(null_filename, O_RDWR);
 336         if (fd < 0) {
 337                 ret = -1;
 338                 goto out;
 339         }
 340
 341         posix_fadvise(fd, 0, 0, POSIX_FADV_RANDOM);
 342         posix_fadvise(fd, 0, 0, POSIX_FADV_NOREUSE);
 343         ret = btrfs_insert_dev_radix(root, fd, device_id,
 344                                      block_start, num_blocks);
 345         BUG_ON(ret);
 346         ret = 0;
 347 out:
 348         free(null_filename);
 349         return ret;
 350 }
 351
 352 static int read_device_info(struct btrfs_root *root)
 353 {
 354         struct btrfs_path path;
 355         int ret;
 356         struct btrfs_key key;
 357         struct btrfs_leaf *leaf;
 358         struct btrfs_device_item *dev_item;
 359         int nritems;
 360         int slot;
 361
 362         root = root->fs_info->dev_root;
 363
 364         btrfs_init_path(&path);
 365         key.objectid = 0;
 366         key.offset = 0;
 367         key.flags = 0;
 368         btrfs_set_key_type(&key, BTRFS_DEV_ITEM_KEY);
 369
 370         ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
 371         leaf = &path.nodes[0]->leaf;
 372         nritems = btrfs_header_nritems(&leaf->header);
 373         while(1) {
 374                 slot = path.slots[0];
 375                 if (slot >= nritems) {
 376                         ret = btrfs_next_leaf(root, &path);
 377                         if (ret)
 378                                 break;
 379                         leaf = &path.nodes[0]->leaf;
 380                         nritems = btrfs_header_nritems(&leaf->header);
 381                         slot = path.slots[0];
 382                 }
 383                 btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
 384                 if (btrfs_key_type(&key) != BTRFS_DEV_ITEM_KEY) {
 385                         path.slots[0]++;
 386                         continue;
 387                 }
 388                 dev_item = btrfs_item_ptr(leaf, slot, struct btrfs_device_item);
 389                 if (btrfs_device_id(dev_item) !=
 390                     btrfs_super_device_id(root->fs_info->disk_super)) {
 391 printf("found key %Lu %Lu\n", key.objectid, key.offset);
 392                         ret = btrfs_open_disk(root, btrfs_device_id(dev_item),
 393                                               key.objectid, key.offset,
 394                                               (char *)(dev_item + 1),
 395                                               btrfs_device_pathlen(dev_item));
 396                         BUG_ON(ret);
 397                 }
 398                 path.slots[0]++;
 399         }
 400         btrfs_release_path(root, &path);
 401         return 0;
 402 }
 403
 404 struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super)
 405 {
 406         int fp;
 407
 408         fp = open(filename, O_CREAT | O_RDWR, 0600);
 409         if (fp < 0) {
 410                 return NULL;
 411         }
 412         return open_ctree_fd(fp, super);
 413 }
 414
 415 struct btrfs_root *open_ctree_fd(int fp, struct btrfs_super_block *super)
 416 {
 417         struct btrfs_root *root = malloc(sizeof(struct btrfs_root));
 418         struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
 419         struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
 420         struct btrfs_root *dev_root = malloc(sizeof(struct btrfs_root));
 421         struct btrfs_fs_info *fs_info = malloc(sizeof(*fs_info));
 422         struct dev_lookup *dev_lookup;
 423         int ret;
 424
 425         INIT_RADIX_TREE(&fs_info->cache_radix, GFP_KERNEL);
 426         INIT_RADIX_TREE(&fs_info->pinned_radix, GFP_KERNEL);
 427         INIT_RADIX_TREE(&fs_info->dev_radix, GFP_KERNEL);
 428         INIT_LIST_HEAD(&fs_info->trans);
 429         INIT_LIST_HEAD(&fs_info->cache);
 430         fs_info->cache_size = 0;
 431         fs_info->fp = fp;
 432         fs_info->running_transaction = NULL;
 433         fs_info->fs_root = root;
 434         fs_info->tree_root = tree_root;
 435         fs_info->extent_root = extent_root;
 436         fs_info->dev_root = dev_root;
 437         fs_info->last_inode_alloc = 0;
 438         fs_info->last_inode_alloc_dirid = 0;
 439         fs_info->disk_super = super;
 440         memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
 441         memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
 442
 443         ret = pread(fp, super, sizeof(struct btrfs_super_block),
 444                      BTRFS_SUPER_INFO_OFFSET);
 445         if (ret == 0 || btrfs_super_root(super) == 0) {
 446                 BUG();
 447                 return NULL;
 448         }
 449         BUG_ON(ret < 0);
 450         __setup_root(super, dev_root, fs_info, BTRFS_DEV_TREE_OBJECTID, fp);
 451
 452         dev_lookup = malloc(sizeof(*dev_lookup));
 453         dev_lookup->fd = fp;
 454         dev_lookup->device_id = btrfs_super_device_id(super);
 455         dev_lookup->block_start = btrfs_super_device_block_start(super);
 456         dev_lookup->num_blocks = btrfs_super_device_num_blocks(super);
 457         ret = radix_tree_insert(&fs_info->dev_radix,
 458                                 dev_lookup->block_start +
 459                                 dev_lookup->num_blocks - 1, dev_lookup);
 460         BUG_ON(ret);
 461
 462         dev_root->node = read_tree_block(dev_root,
 463                                          btrfs_super_device_root(super));
 464
 465         ret = read_device_info(dev_root);
 466         BUG_ON(ret);
 467
 468         __setup_root(super, tree_root, fs_info, BTRFS_ROOT_TREE_OBJECTID, fp);
 469         tree_root->node = read_tree_block(tree_root, btrfs_super_root(super));
 470         BUG_ON(!tree_root->node);
 471
 472         ret = find_and_setup_root(super, tree_root, fs_info,
 473                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root, fp);
 474         BUG_ON(ret);
 475
 476         ret = find_and_setup_root(super, tree_root, fs_info,
 477                                   BTRFS_FS_TREE_OBJECTID, root, fp);
 478         BUG_ON(ret);
 479
 480         root->commit_root = root->node;
 481         root->node->count++;
 482         root->ref_cows = 1;
 483         root->fs_info->generation = root->root_key.offset + 1;
 484         return root;
 485 }
 486
 487 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
 488                       *root, struct btrfs_super_block *s)
 489 {
 490         int ret;
 491         btrfs_set_super_root(s, root->fs_info->tree_root->node->blocknr);
 492         ret = pwrite(root->fs_info->fp, s, sizeof(*s),
 493                      BTRFS_SUPER_INFO_OFFSET);
 494         if (ret != sizeof(*s)) {
 495                 fprintf(stderr, "failed to write new super block err %d\n", ret);
 496                 return ret;
 497         }
 498         return 0;
 499 }
 500
 501 static int drop_cache(struct btrfs_root *root)
 502 {
 503         while(!list_empty(&root->fs_info->cache)) {
 504                 struct btrfs_buffer *b = list_entry(root->fs_info->cache.next,
 505                                                     struct btrfs_buffer,
 506                                                     cache);
 507                 list_del_init(&b->cache);
 508                 btrfs_block_release(root, b);
 509         }
 510         return 0;
 511 }
 512
 513 static int free_dev_radix(struct btrfs_fs_info *fs_info)
 514 {
 515         struct dev_lookup *lookup[8];
 516         int ret;
 517         int i;
 518         while(1) {
 519                 ret = radix_tree_gang_lookup(&fs_info->dev_radix,
 520                                              (void **)lookup, 0,
 521                                              ARRAY_SIZE(lookup));
 522                 if (!ret)
 523                         break;
 524                 for (i = 0; i < ret; i++) {
 525                         if (lookup[i]->device_id !=
 526                             btrfs_super_device_id(fs_info->disk_super))
 527                                 close(lookup[i]->fd);
 528                         radix_tree_delete(&fs_info->dev_radix,
 529                                           lookup[i]->block_start +
 530                                           lookup[i]->num_blocks - 1);
 531                         free(lookup[i]);
 532                 }
 533         }
 534         return 0;
 535 }
 536
 537 int close_ctree(struct btrfs_root *root, struct btrfs_super_block *s)
 538 {
 539         int ret;
 540         struct btrfs_trans_handle *trans;
 541
 542         trans = root->fs_info->running_transaction;
 543         btrfs_commit_transaction(trans, root, s);
 544         ret = commit_tree_roots(trans, root->fs_info);
 545         BUG_ON(ret);
 546         ret = __commit_transaction(trans, root);
 547         BUG_ON(ret);
 548         write_ctree_super(trans, root, s);
 549         drop_cache(root);
 550         BUG_ON(!list_empty(&root->fs_info->trans));
 551
 552         free_dev_radix(root->fs_info);
 553         close(root->fs_info->fp);
 554         if (root->node)
 555                 btrfs_block_release(root, root->node);
 556         if (root->fs_info->extent_root->node)
 557                 btrfs_block_release(root->fs_info->extent_root,
 558                                     root->fs_info->extent_root->node);
 559         if (root->fs_info->tree_root->node)
 560                 btrfs_block_release(root->fs_info->tree_root,
 561                                     root->fs_info->tree_root->node);
 562         if (root->fs_info->dev_root->node)
 563                 btrfs_block_release(root->fs_info->dev_root,
 564                                     root->fs_info->dev_root->node);
 565         btrfs_block_release(root, root->commit_root);
 566         free(root);
 567         printf("on close %d blocks are allocated\n", allocated_blocks);
 568         return 0;
 569 }
 570
 571 void btrfs_block_release(struct btrfs_root *root, struct btrfs_buffer *buf)
 572 {
 573         buf->count--;
 574         if (buf->count < 0)
 575                 BUG();
 576         if (buf->count == 0) {
 577                 BUG_ON(!list_empty(&buf->cache));
 578                 BUG_ON(!list_empty(&buf->dirty));
 579                 if (!radix_tree_lookup(&root->fs_info->cache_radix,
 580                                        buf->blocknr))
 581                         BUG();
 582                 radix_tree_delete(&root->fs_info->cache_radix, buf->blocknr);
 583                 memset(buf, 0, sizeof(*buf));
 584                 free(buf);
 585                 BUG_ON(allocated_blocks == 0);
 586                 allocated_blocks--;
 587                 BUG_ON(root->fs_info->cache_size == 0);
 588                 root->fs_info->cache_size--;
 589         }
 590 }
 591