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                 if (check_tree_block(root, buf))
 150                         BUG();
 151         } else {
 152                 buf = alloc_tree_block(root, blocknr);
 153                 if (!buf)
 154                         return NULL;
 155                 btrfs_map_bh_to_logical(root, buf, blocknr);
 156                 ret = pread(buf->fd, &buf->node, root->blocksize,
 157                             buf->dev_blocknr * root->blocksize);
 158                 if (ret != root->blocksize) {
 159                         free(buf);
 160                         return NULL;
 161                 }
 162                 if (check_tree_block(root, buf))
 163                         BUG();
 164         }
 165         return buf;
 166 }
 167
 168 int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 169                      struct btrfs_buffer *buf)
 170 {
 171         if (!list_empty(&buf->dirty))
 172                 return 0;
 173         list_add_tail(&buf->dirty, &root->fs_info->trans);
 174         buf->count++;
 175         if (check_tree_block(root, buf))
 176                 BUG();
 177         return 0;
 178 }
 179
 180 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 181                      struct btrfs_buffer *buf)
 182 {
 183         if (!list_empty(&buf->dirty)) {
 184                 list_del_init(&buf->dirty);
 185                 btrfs_block_release(root, buf);
 186         }
 187         return 0;
 188 }
 189
 190 int write_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 191                      struct btrfs_buffer *buf)
 192 {
 193         int ret;
 194
 195         if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
 196                 BUG();
 197         btrfs_map_bh_to_logical(root, buf, buf->blocknr);
 198         if (check_tree_block(root, buf))
 199                 BUG();
 200         ret = pwrite(buf->fd, &buf->node, root->blocksize,
 201                      buf->dev_blocknr * root->blocksize);
 202         if (ret != root->blocksize)
 203                 return ret;
 204         return 0;
 205 }
 206
 207 static int __commit_transaction(struct btrfs_trans_handle *trans, struct
 208                                 btrfs_root *root)
 209 {
 210         struct btrfs_buffer *b;
 211         int ret = 0;
 212         int wret;
 213         while(!list_empty(&root->fs_info->trans)) {
 214                 b = list_entry(root->fs_info->trans.next, struct btrfs_buffer,
 215                                dirty);
 216                 list_del_init(&b->dirty);
 217                 wret = write_tree_block(trans, root, b);
 218                 if (wret)
 219                         ret = wret;
 220                 btrfs_block_release(root, b);
 221         }
 222         return ret;
 223 }
 224
 225 static int commit_tree_roots(struct btrfs_trans_handle *trans,
 226                              struct btrfs_fs_info *fs_info)
 227 {
 228         int ret;
 229         u64 old_extent_block;
 230         struct btrfs_root *tree_root = fs_info->tree_root;
 231         struct btrfs_root *extent_root = fs_info->extent_root;
 232
 233         if (btrfs_super_device_root(fs_info->disk_super) !=
 234             fs_info->dev_root->node->blocknr) {
 235                 btrfs_set_super_device_root(fs_info->disk_super,
 236                                             fs_info->dev_root->node->blocknr);
 237         }
 238         btrfs_write_dirty_block_groups(trans, fs_info->extent_root);
 239         while(1) {
 240                 old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
 241                 if (old_extent_block == extent_root->node->blocknr)
 242                         break;
 243                 btrfs_set_root_blocknr(&extent_root->root_item,
 244                                        extent_root->node->blocknr);
 245                 ret = btrfs_update_root(trans, tree_root,
 246                                         &extent_root->root_key,
 247                                         &extent_root->root_item);
 248                 BUG_ON(ret);
 249                 btrfs_write_dirty_block_groups(trans, fs_info->extent_root);
 250         }
 251         return 0;
 252 }
 253
 254 int btrfs_commit_transaction(struct btrfs_trans_handle *trans, struct
 255                              btrfs_root *root, struct btrfs_super_block *s)
 256 {
 257         int ret = 0;
 258         struct btrfs_buffer *snap = root->commit_root;
 259         struct btrfs_key snap_key;
 260
 261         if (root->commit_root == root->node)
 262                 return 0;
 263
 264         memcpy(&snap_key, &root->root_key, sizeof(snap_key));
 265         root->root_key.offset++;
 266
 267         btrfs_set_root_blocknr(&root->root_item, root->node->blocknr);
 268         ret = btrfs_insert_root(trans, root->fs_info->tree_root,
 269                                 &root->root_key, &root->root_item);
 270         BUG_ON(ret);
 271
 272         ret = commit_tree_roots(trans, root->fs_info);
 273         BUG_ON(ret);
 274
 275         ret = __commit_transaction(trans, root);
 276         BUG_ON(ret);
 277
 278         write_ctree_super(trans, root, s);
 279         btrfs_finish_extent_commit(trans, root->fs_info->extent_root);
 280         btrfs_finish_extent_commit(trans, root->fs_info->tree_root);
 281
 282         root->commit_root = root->node;
 283         root->node->count++;
 284         ret = btrfs_drop_snapshot(trans, root, snap);
 285         BUG_ON(ret);
 286
 287         ret = btrfs_del_root(trans, root->fs_info->tree_root, &snap_key);
 288         BUG_ON(ret);
 289         root->fs_info->generation = root->root_key.offset + 1;
 290
 291         return ret;
 292 }
 293
 294 static int __setup_root(struct btrfs_super_block *super,
 295                         struct btrfs_root *root,
 296                         struct btrfs_fs_info *fs_info,
 297                         u64 objectid, int fp)
 298 {
 299         root->node = NULL;
 300         root->commit_root = NULL;
 301         root->blocksize = btrfs_super_blocksize(super);
 302         root->ref_cows = 0;
 303         root->fs_info = fs_info;
 304         memset(&root->root_key, 0, sizeof(root->root_key));
 305         memset(&root->root_item, 0, sizeof(root->root_item));
 306         root->root_key.objectid = objectid;
 307         return 0;
 308 }
 309
 310 static int find_and_setup_root(struct btrfs_super_block *super,
 311                                struct btrfs_root *tree_root,
 312                                struct btrfs_fs_info *fs_info,
 313                                u64 objectid,
 314                                struct btrfs_root *root, int fp)
 315 {
 316         int ret;
 317
 318         __setup_root(super, root, fs_info, objectid, fp);
 319         ret = btrfs_find_last_root(tree_root, objectid,
 320                                    &root->root_item, &root->root_key);
 321         BUG_ON(ret);
 322
 323         root->node = read_tree_block(root,
 324                                      btrfs_root_blocknr(&root->root_item));
 325         BUG_ON(!root->node);
 326         return 0;
 327 }
 328
 329 int btrfs_open_disk(struct btrfs_root *root, u64 device_id,
 330                     u64 block_start, u64 num_blocks,
 331                     char *filename, int name_len)
 332 {
 333         char *null_filename;
 334         int fd;
 335         int ret;
 336
 337         null_filename = malloc(name_len + 1);
 338         if (!null_filename)
 339                 return -ENOMEM;
 340         memcpy(null_filename, filename, name_len);
 341         null_filename[name_len] = '\0';
 342
 343         fd = open(null_filename, O_RDWR);
 344         if (fd < 0) {
 345                 ret = -1;
 346                 goto out;
 347         }
 348
 349         posix_fadvise(fd, 0, 0, POSIX_FADV_RANDOM);
 350         posix_fadvise(fd, 0, 0, POSIX_FADV_NOREUSE);
 351         ret = btrfs_insert_dev_radix(root, fd, device_id,
 352                                      block_start, num_blocks);
 353         BUG_ON(ret);
 354         ret = 0;
 355 out:
 356         free(null_filename);
 357         return ret;
 358 }
 359
 360 static int read_device_info(struct btrfs_root *root)
 361 {
 362         struct btrfs_path path;
 363         int ret;
 364         struct btrfs_key key;
 365         struct btrfs_leaf *leaf;
 366         struct btrfs_device_item *dev_item;
 367         int nritems;
 368         int slot;
 369
 370         root = root->fs_info->dev_root;
 371
 372         btrfs_init_path(&path);
 373         key.objectid = 0;
 374         key.offset = 0;
 375         key.flags = 0;
 376         btrfs_set_key_type(&key, BTRFS_DEV_ITEM_KEY);
 377
 378         ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
 379         leaf = &path.nodes[0]->leaf;
 380         nritems = btrfs_header_nritems(&leaf->header);
 381         while(1) {
 382                 slot = path.slots[0];
 383                 if (slot >= nritems) {
 384                         ret = btrfs_next_leaf(root, &path);
 385                         if (ret)
 386                                 break;
 387                         leaf = &path.nodes[0]->leaf;
 388                         nritems = btrfs_header_nritems(&leaf->header);
 389                         slot = path.slots[0];
 390                 }
 391                 btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
 392                 if (btrfs_key_type(&key) != BTRFS_DEV_ITEM_KEY) {
 393                         path.slots[0]++;
 394                         continue;
 395                 }
 396                 dev_item = btrfs_item_ptr(leaf, slot, struct btrfs_device_item);
 397                 if (btrfs_device_id(dev_item) !=
 398                     btrfs_super_device_id(root->fs_info->disk_super)) {
 399 printf("found key %Lu %Lu\n", key.objectid, key.offset);
 400                         ret = btrfs_open_disk(root, btrfs_device_id(dev_item),
 401                                               key.objectid, key.offset,
 402                                               (char *)(dev_item + 1),
 403                                               btrfs_device_pathlen(dev_item));
 404                         BUG_ON(ret);
 405                 }
 406                 path.slots[0]++;
 407         }
 408         btrfs_release_path(root, &path);
 409         return 0;
 410 }
 411
 412 struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super)
 413 {
 414         int fp;
 415
 416         fp = open(filename, O_CREAT | O_RDWR, 0600);
 417         if (fp < 0) {
 418                 return NULL;
 419         }
 420         return open_ctree_fd(fp, super);
 421 }
 422
 423 struct btrfs_root *open_ctree_fd(int fp, struct btrfs_super_block *super)
 424 {
 425         struct btrfs_root *root = malloc(sizeof(struct btrfs_root));
 426         struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
 427         struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
 428         struct btrfs_root *dev_root = malloc(sizeof(struct btrfs_root));
 429         struct btrfs_fs_info *fs_info = malloc(sizeof(*fs_info));
 430         struct dev_lookup *dev_lookup;
 431         int ret;
 432
 433         INIT_RADIX_TREE(&fs_info->cache_radix, GFP_KERNEL);
 434         INIT_RADIX_TREE(&fs_info->pinned_radix, GFP_KERNEL);
 435         INIT_RADIX_TREE(&fs_info->dev_radix, GFP_KERNEL);
 436         INIT_RADIX_TREE(&fs_info->block_group_radix, GFP_KERNEL);
 437         INIT_LIST_HEAD(&fs_info->trans);
 438         INIT_LIST_HEAD(&fs_info->cache);
 439         fs_info->cache_size = 0;
 440         fs_info->fp = fp;
 441         fs_info->running_transaction = NULL;
 442         fs_info->fs_root = root;
 443         fs_info->tree_root = tree_root;
 444         fs_info->extent_root = extent_root;
 445         fs_info->dev_root = dev_root;
 446         fs_info->last_inode_alloc = 0;
 447         fs_info->last_inode_alloc_dirid = 0;
 448         fs_info->disk_super = super;
 449         memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
 450         memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
 451
 452         ret = pread(fp, super, sizeof(struct btrfs_super_block),
 453                      BTRFS_SUPER_INFO_OFFSET);
 454         if (ret == 0 || btrfs_super_root(super) == 0) {
 455                 BUG();
 456                 return NULL;
 457         }
 458         BUG_ON(ret < 0);
 459         __setup_root(super, dev_root, fs_info, BTRFS_DEV_TREE_OBJECTID, fp);
 460
 461         dev_lookup = malloc(sizeof(*dev_lookup));
 462         dev_lookup->fd = fp;
 463         dev_lookup->device_id = btrfs_super_device_id(super);
 464         dev_lookup->block_start = btrfs_super_device_block_start(super);
 465         dev_lookup->num_blocks = btrfs_super_device_num_blocks(super);
 466         ret = radix_tree_insert(&fs_info->dev_radix,
 467                                 dev_lookup->block_start +
 468                                 dev_lookup->num_blocks - 1, dev_lookup);
 469         BUG_ON(ret);
 470
 471         dev_root->node = read_tree_block(dev_root,
 472                                          btrfs_super_device_root(super));
 473
 474         ret = read_device_info(dev_root);
 475         BUG_ON(ret);
 476
 477         __setup_root(super, tree_root, fs_info, BTRFS_ROOT_TREE_OBJECTID, fp);
 478         tree_root->node = read_tree_block(tree_root, btrfs_super_root(super));
 479         BUG_ON(!tree_root->node);
 480
 481         ret = find_and_setup_root(super, tree_root, fs_info,
 482                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root, fp);
 483         BUG_ON(ret);
 484
 485         ret = find_and_setup_root(super, tree_root, fs_info,
 486                                   BTRFS_FS_TREE_OBJECTID, root, fp);
 487         BUG_ON(ret);
 488
 489         root->commit_root = root->node;
 490         root->node->count++;
 491         root->ref_cows = 1;
 492         root->fs_info->generation = root->root_key.offset + 1;
 493         btrfs_read_block_groups(root);
 494         return root;
 495 }
 496
 497 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
 498                       *root, struct btrfs_super_block *s)
 499 {
 500         int ret;
 501         btrfs_set_super_root(s, root->fs_info->tree_root->node->blocknr);
 502         ret = pwrite(root->fs_info->fp, s, sizeof(*s),
 503                      BTRFS_SUPER_INFO_OFFSET);
 504         if (ret != sizeof(*s)) {
 505                 fprintf(stderr, "failed to write new super block err %d\n", ret);
 506                 return ret;
 507         }
 508         return 0;
 509 }
 510
 511 static int drop_cache(struct btrfs_root *root)
 512 {
 513         while(!list_empty(&root->fs_info->cache)) {
 514                 struct btrfs_buffer *b = list_entry(root->fs_info->cache.next,
 515                                                     struct btrfs_buffer,
 516                                                     cache);
 517                 list_del_init(&b->cache);
 518                 btrfs_block_release(root, b);
 519         }
 520         return 0;
 521 }
 522
 523 static int free_dev_radix(struct btrfs_fs_info *fs_info)
 524 {
 525         struct dev_lookup *lookup[8];
 526         int ret;
 527         int i;
 528         while(1) {
 529                 ret = radix_tree_gang_lookup(&fs_info->dev_radix,
 530                                              (void **)lookup, 0,
 531                                              ARRAY_SIZE(lookup));
 532                 if (!ret)
 533                         break;
 534                 for (i = 0; i < ret; i++) {
 535                         if (lookup[i]->device_id !=
 536                             btrfs_super_device_id(fs_info->disk_super))
 537                                 close(lookup[i]->fd);
 538                         radix_tree_delete(&fs_info->dev_radix,
 539                                           lookup[i]->block_start +
 540                                           lookup[i]->num_blocks - 1);
 541                         free(lookup[i]);
 542                 }
 543         }
 544         return 0;
 545 }
 546
 547 int close_ctree(struct btrfs_root *root, struct btrfs_super_block *s)
 548 {
 549         int ret;
 550         struct btrfs_trans_handle *trans;
 551
 552         trans = root->fs_info->running_transaction;
 553         btrfs_commit_transaction(trans, root, s);
 554         ret = commit_tree_roots(trans, root->fs_info);
 555         BUG_ON(ret);
 556         ret = __commit_transaction(trans, root);
 557         BUG_ON(ret);
 558         write_ctree_super(trans, root, s);
 559         drop_cache(root);
 560         BUG_ON(!list_empty(&root->fs_info->trans));
 561
 562         free_dev_radix(root->fs_info);
 563         btrfs_free_block_groups(root->fs_info);
 564         close(root->fs_info->fp);
 565         if (root->node)
 566                 btrfs_block_release(root, root->node);
 567         if (root->fs_info->extent_root->node)
 568                 btrfs_block_release(root->fs_info->extent_root,
 569                                     root->fs_info->extent_root->node);
 570         if (root->fs_info->tree_root->node)
 571                 btrfs_block_release(root->fs_info->tree_root,
 572                                     root->fs_info->tree_root->node);
 573         if (root->fs_info->dev_root->node)
 574                 btrfs_block_release(root->fs_info->dev_root,
 575                                     root->fs_info->dev_root->node);
 576         btrfs_block_release(root, root->commit_root);
 577         free(root);
 578         printf("on close %d blocks are allocated\n", allocated_blocks);
 579         return 0;
 580 }
 581
 582 void btrfs_block_release(struct btrfs_root *root, struct btrfs_buffer *buf)
 583 {
 584         buf->count--;
 585         if (buf->count < 0)
 586                 BUG();
 587         if (buf->count == 0) {
 588                 BUG_ON(!list_empty(&buf->cache));
 589                 BUG_ON(!list_empty(&buf->dirty));
 590                 if (!radix_tree_lookup(&root->fs_info->cache_radix,
 591                                        buf->blocknr))
 592                         BUG();
 593                 radix_tree_delete(&root->fs_info->cache_radix, buf->blocknr);
 594                 memset(buf, 0, sizeof(*buf));
 595                 free(buf);
 596                 BUG_ON(allocated_blocks == 0);
 597                 allocated_blocks--;
 598                 BUG_ON(root->fs_info->cache_size == 0);
 599                 root->fs_info->cache_size--;
 600         }
 601 }
 602