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 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <fcntl.h>
  26 #include <unistd.h>
  27 #include "kerncompat.h"
  28 #include "radix-tree.h"
  29 #include "ctree.h"
  30 #include "disk-io.h"
  31 #include "transaction.h"
  32 #include "crc32c.h"
  33
  34 static u64 allocated_bytes = 0;
  35 int cache_max = 10000;
  36
  37 int btrfs_map_bh_to_logical(struct btrfs_root *root, struct btrfs_buffer *bh,
  38                              u64 logical)
  39 {
  40         bh->fd = root->fs_info->fp;
  41         bh->dev_bytenr = logical;
  42         return 0;
  43 }
  44
  45 static int check_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
  46 {
  47         if (buf->bytenr != btrfs_header_bytenr(&buf->node.header))
  48                 BUG();
  49         if (memcmp(root->fs_info->disk_super->fsid, buf->node.header.fsid,
  50                    sizeof(buf->node.header.fsid)))
  51                 BUG();
  52         return 0;
  53 }
  54
  55 static int free_some_buffers(struct btrfs_root *root)
  56 {
  57         struct list_head *node, *next;
  58         struct btrfs_buffer *b;
  59         if (root->fs_info->cache_size < cache_max)
  60                 return 0;
  61         list_for_each_safe(node, next, &root->fs_info->cache) {
  62                 b = list_entry(node, struct btrfs_buffer, cache);
  63                 if (b->count == 1) {
  64                         BUG_ON(!list_empty(&b->dirty));
  65                         list_del_init(&b->cache);
  66                         btrfs_block_release(root, b);
  67                         if (root->fs_info->cache_size < cache_max)
  68                                 break;
  69                 }
  70         }
  71         return 0;
  72 }
  73
  74 struct btrfs_buffer *alloc_tree_block(struct btrfs_root *root, u64 bytenr,
  75                                       u32 blocksize)
  76 {
  77         struct btrfs_buffer *buf;
  78         int ret;
  79
  80         buf = malloc(sizeof(struct btrfs_buffer) + blocksize);
  81         if (!buf)
  82                 return buf;
  83         allocated_bytes += blocksize;
  84
  85         buf->bytenr = bytenr;
  86         buf->count = 2;
  87         buf->size = blocksize;
  88
  89         INIT_LIST_HEAD(&buf->dirty);
  90         free_some_buffers(root);
  91         radix_tree_preload(GFP_KERNEL);
  92         ret = radix_tree_insert(&root->fs_info->cache_radix, bytenr, buf);
  93         radix_tree_preload_end();
  94         list_add_tail(&buf->cache, &root->fs_info->cache);
  95         root->fs_info->cache_size += blocksize;
  96         if (ret) {
  97                 free(buf);
  98                 return NULL;
  99         }
 100         return buf;
 101 }
 102
 103 struct btrfs_buffer *find_tree_block(struct btrfs_root *root, u64 bytenr,
 104                                      u32 blocksize)
 105 {
 106         struct btrfs_buffer *buf;
 107         buf = radix_tree_lookup(&root->fs_info->cache_radix, bytenr);
 108         if (buf) {
 109                 buf->count++;
 110         } else {
 111                 buf = alloc_tree_block(root, bytenr, blocksize);
 112                 if (!buf) {
 113                         BUG();
 114                         return NULL;
 115                 }
 116         }
 117         return buf;
 118 }
 119
 120 struct btrfs_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 121                                      u32 blocksize)
 122 {
 123         struct btrfs_buffer *buf;
 124         int ret;
 125         buf = radix_tree_lookup(&root->fs_info->cache_radix, bytenr);
 126         if (buf) {
 127                 buf->count++;
 128                 if (check_tree_block(root, buf))
 129                         BUG();
 130         } else {
 131                 buf = alloc_tree_block(root, bytenr, blocksize);
 132                 if (!buf)
 133                         return NULL;
 134                 btrfs_map_bh_to_logical(root, buf, bytenr);
 135                 ret = pread(buf->fd, &buf->node, blocksize,
 136                             buf->dev_bytenr);
 137                 if (ret != blocksize) {
 138                         free(buf);
 139                         return NULL;
 140                 }
 141                 if (check_tree_block(root, buf))
 142                         BUG();
 143         }
 144         return buf;
 145 }
 146
 147 int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 148                      struct btrfs_buffer *buf)
 149 {
 150         if (!list_empty(&buf->dirty))
 151                 return 0;
 152         list_add_tail(&buf->dirty, &root->fs_info->trans);
 153         buf->count++;
 154         if (check_tree_block(root, buf))
 155                 BUG();
 156         return 0;
 157 }
 158
 159 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 160                      struct btrfs_buffer *buf)
 161 {
 162         if (!list_empty(&buf->dirty)) {
 163                 list_del_init(&buf->dirty);
 164                 btrfs_block_release(root, buf);
 165         }
 166         return 0;
 167 }
 168
 169 int btrfs_csum_node(struct btrfs_root *root, struct btrfs_node *node)
 170 {
 171         u32 crc;
 172         size_t len = btrfs_level_size(root, btrfs_header_level(&node->header)) -
 173                                       BTRFS_CSUM_SIZE;
 174
 175         crc = crc32c(0, (char *)(node) + BTRFS_CSUM_SIZE, len);
 176         memcpy(node->header.csum, &crc, BTRFS_CRC32_SIZE);
 177         return 0;
 178 }
 179
 180 int btrfs_csum_super(struct btrfs_root *root, struct btrfs_super_block *super)
 181 {
 182         u32 crc;
 183         char block[root->sectorsize];
 184         size_t len = root->sectorsize - BTRFS_CSUM_SIZE;
 185
 186         memset(block, 0, root->sectorsize);
 187         memcpy(block, super, sizeof(*super));
 188
 189         crc = crc32c(0, block + BTRFS_CSUM_SIZE, len);
 190         memcpy(super->csum, &crc, BTRFS_CRC32_SIZE);
 191         return 0;
 192 }
 193
 194 int write_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 195                      struct btrfs_buffer *buf)
 196 {
 197         int ret;
 198
 199         if (buf->bytenr != btrfs_header_bytenr(&buf->node.header))
 200                 BUG();
 201         btrfs_map_bh_to_logical(root, buf, buf->bytenr);
 202         if (check_tree_block(root, buf))
 203                 BUG();
 204
 205         btrfs_csum_node(root, &buf->node);
 206
 207         ret = pwrite(buf->fd, &buf->node, buf->size,
 208                      buf->dev_bytenr);
 209         if (ret != buf->size)
 210                 return ret;
 211         return 0;
 212 }
 213
 214 static int __commit_transaction(struct btrfs_trans_handle *trans, struct
 215                                 btrfs_root *root)
 216 {
 217         struct btrfs_buffer *b;
 218         int ret = 0;
 219         int wret;
 220         while(!list_empty(&root->fs_info->trans)) {
 221                 b = list_entry(root->fs_info->trans.next, struct btrfs_buffer,
 222                                dirty);
 223                 list_del_init(&b->dirty);
 224                 wret = write_tree_block(trans, root, b);
 225                 if (wret)
 226                         ret = wret;
 227                 btrfs_block_release(root, b);
 228         }
 229         return ret;
 230 }
 231
 232 static int commit_tree_roots(struct btrfs_trans_handle *trans,
 233                              struct btrfs_fs_info *fs_info)
 234 {
 235         int ret;
 236         u64 old_extent_bytenr;
 237         struct btrfs_root *tree_root = fs_info->tree_root;
 238         struct btrfs_root *extent_root = fs_info->extent_root;
 239
 240         btrfs_write_dirty_block_groups(trans, fs_info->extent_root);
 241         while(1) {
 242                 old_extent_bytenr = btrfs_root_bytenr(&extent_root->root_item);
 243                 if (old_extent_bytenr == extent_root->node->bytenr)
 244                         break;
 245                 btrfs_set_root_bytenr(&extent_root->root_item,
 246                                        extent_root->node->bytenr);
 247                 extent_root->root_item.level =
 248                         btrfs_header_level(&extent_root->node->node.header);
 249                 ret = btrfs_update_root(trans, tree_root,
 250                                         &extent_root->root_key,
 251                                         &extent_root->root_item);
 252                 BUG_ON(ret);
 253                 btrfs_write_dirty_block_groups(trans, fs_info->extent_root);
 254         }
 255         return 0;
 256 }
 257
 258 int btrfs_commit_transaction(struct btrfs_trans_handle *trans, struct
 259                              btrfs_root *root, struct btrfs_super_block *s)
 260 {
 261         int ret = 0;
 262         struct btrfs_buffer *snap = root->commit_root;
 263         struct btrfs_key snap_key;
 264
 265         if (root->commit_root == root->node)
 266                 return 0;
 267
 268         memcpy(&snap_key, &root->root_key, sizeof(snap_key));
 269         root->root_key.offset++;
 270
 271         btrfs_set_root_bytenr(&root->root_item, root->node->bytenr);
 272         root->root_item.level =
 273                         btrfs_header_level(&root->node->node.header);
 274         ret = btrfs_insert_root(trans, root->fs_info->tree_root,
 275                                 &root->root_key, &root->root_item);
 276         BUG_ON(ret);
 277
 278         ret = commit_tree_roots(trans, root->fs_info);
 279         BUG_ON(ret);
 280
 281         ret = __commit_transaction(trans, root);
 282         BUG_ON(ret);
 283
 284         write_ctree_super(trans, root, s);
 285         btrfs_finish_extent_commit(trans, root->fs_info->extent_root);
 286         btrfs_finish_extent_commit(trans, root->fs_info->tree_root);
 287
 288         root->commit_root = root->node;
 289         root->node->count++;
 290         ret = btrfs_drop_snapshot(trans, root, snap);
 291         BUG_ON(ret);
 292
 293         ret = btrfs_del_root(trans, root->fs_info->tree_root, &snap_key);
 294         BUG_ON(ret);
 295         root->fs_info->generation = root->root_key.offset + 1;
 296
 297         return ret;
 298 }
 299
 300 static int __setup_root(struct btrfs_super_block *super,
 301                         struct btrfs_root *root,
 302                         struct btrfs_fs_info *fs_info,
 303                         u64 objectid, int fp)
 304 {
 305         root->node = NULL;
 306         root->commit_root = NULL;
 307         root->sectorsize = btrfs_super_sectorsize(super);
 308         root->nodesize = btrfs_super_nodesize(super);
 309         root->leafsize = btrfs_super_leafsize(super);
 310         root->ref_cows = 0;
 311         root->fs_info = fs_info;
 312         memset(&root->root_key, 0, sizeof(root->root_key));
 313         memset(&root->root_item, 0, sizeof(root->root_item));
 314         root->root_key.objectid = objectid;
 315         return 0;
 316 }
 317
 318 struct btrfs_buffer *read_root_block(struct btrfs_root *root, u64 bytenr,
 319                                             u8 level)
 320 {
 321         struct btrfs_buffer *node;
 322         u32 size = btrfs_level_size(root, level);
 323
 324         node = read_tree_block(root, bytenr, size);
 325         BUG_ON(!node);
 326         return node;
 327 }
 328
 329 static int find_and_setup_root(struct btrfs_super_block *super,
 330                                struct btrfs_root *tree_root,
 331                                struct btrfs_fs_info *fs_info,
 332                                u64 objectid,
 333                                struct btrfs_root *root, int fp)
 334 {
 335         int ret;
 336
 337         __setup_root(super, root, fs_info, objectid, fp);
 338         ret = btrfs_find_last_root(tree_root, objectid,
 339                                    &root->root_item, &root->root_key);
 340         BUG_ON(ret);
 341         root->node = read_root_block(root,
 342                                      btrfs_root_bytenr(&root->root_item),
 343                                      root->root_item.level);
 344         BUG_ON(!root->node);
 345         return 0;
 346 }
 347
 348 struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super)
 349 {
 350         int fp;
 351
 352         fp = open(filename, O_CREAT | O_RDWR, 0600);
 353         if (fp < 0) {
 354                 return NULL;
 355         }
 356         return open_ctree_fd(fp, super);
 357 }
 358
 359 struct btrfs_root *open_ctree_fd(int fp, struct btrfs_super_block *super)
 360 {
 361         struct btrfs_root *root = malloc(sizeof(struct btrfs_root));
 362         struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
 363         struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
 364         struct btrfs_fs_info *fs_info = malloc(sizeof(*fs_info));
 365         int ret;
 366
 367         INIT_RADIX_TREE(&fs_info->cache_radix, GFP_KERNEL);
 368         INIT_RADIX_TREE(&fs_info->block_group_radix, GFP_KERNEL);
 369         INIT_LIST_HEAD(&fs_info->trans);
 370         INIT_LIST_HEAD(&fs_info->cache);
 371         pending_tree_init(&fs_info->pending_tree);
 372         pending_tree_init(&fs_info->pinned_tree);
 373         pending_tree_init(&fs_info->del_pending);
 374         fs_info->cache_size = 0;
 375         fs_info->fp = fp;
 376         fs_info->running_transaction = NULL;
 377         fs_info->fs_root = root;
 378         fs_info->tree_root = tree_root;
 379         fs_info->extent_root = extent_root;
 380         fs_info->last_inode_alloc = 0;
 381         fs_info->last_inode_alloc_dirid = 0;
 382         fs_info->disk_super = super;
 383         memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
 384
 385         ret = pread(fp, super, sizeof(struct btrfs_super_block),
 386                      BTRFS_SUPER_INFO_OFFSET);
 387         if (ret == 0 || btrfs_super_root(super) == 0) {
 388                 BUG();
 389                 return NULL;
 390         }
 391         BUG_ON(ret < 0);
 392
 393         __setup_root(super, tree_root, fs_info, BTRFS_ROOT_TREE_OBJECTID, fp);
 394         tree_root->node = read_root_block(tree_root, btrfs_super_root(super),
 395                                           btrfs_super_root_level(super));
 396         BUG_ON(!tree_root->node);
 397
 398         ret = find_and_setup_root(super, tree_root, fs_info,
 399                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root, fp);
 400         BUG_ON(ret);
 401
 402         ret = find_and_setup_root(super, tree_root, fs_info,
 403                                   BTRFS_FS_TREE_OBJECTID, root, fp);
 404         BUG_ON(ret);
 405
 406         root->commit_root = root->node;
 407         root->node->count++;
 408         root->ref_cows = 1;
 409         root->fs_info->generation = root->root_key.offset + 1;
 410         btrfs_read_block_groups(root);
 411         return root;
 412 }
 413
 414 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
 415                       *root, struct btrfs_super_block *s)
 416 {
 417         int ret;
 418
 419         btrfs_set_super_root(s, root->fs_info->tree_root->node->bytenr);
 420         btrfs_set_super_root_level(s,
 421               btrfs_header_level(&root->fs_info->tree_root->node->node.header));
 422         btrfs_csum_super(root, s);
 423
 424         ret = pwrite(root->fs_info->fp, s, sizeof(*s),
 425                      BTRFS_SUPER_INFO_OFFSET);
 426         if (ret != sizeof(*s)) {
 427                 fprintf(stderr, "failed to write new super block err %d\n", ret);
 428                 return ret;
 429         }
 430         return 0;
 431 }
 432
 433 static int drop_cache(struct btrfs_root *root)
 434 {
 435         while(!list_empty(&root->fs_info->cache)) {
 436                 struct btrfs_buffer *b = list_entry(root->fs_info->cache.next,
 437                                                     struct btrfs_buffer,
 438                                                     cache);
 439                 list_del_init(&b->cache);
 440                 btrfs_block_release(root, b);
 441         }
 442         return 0;
 443 }
 444
 445 int close_ctree(struct btrfs_root *root, struct btrfs_super_block *s)
 446 {
 447         int ret;
 448         struct btrfs_trans_handle *trans;
 449
 450         trans = root->fs_info->running_transaction;
 451         btrfs_commit_transaction(trans, root, s);
 452         ret = commit_tree_roots(trans, root->fs_info);
 453         BUG_ON(ret);
 454         ret = __commit_transaction(trans, root);
 455         BUG_ON(ret);
 456         write_ctree_super(trans, root, s);
 457         drop_cache(root);
 458         BUG_ON(!list_empty(&root->fs_info->trans));
 459
 460         btrfs_free_block_groups(root->fs_info);
 461         close(root->fs_info->fp);
 462         if (root->node)
 463                 btrfs_block_release(root, root->node);
 464         if (root->fs_info->extent_root->node)
 465                 btrfs_block_release(root->fs_info->extent_root,
 466                                     root->fs_info->extent_root->node);
 467         if (root->fs_info->tree_root->node)
 468                 btrfs_block_release(root->fs_info->tree_root,
 469                                     root->fs_info->tree_root->node);
 470         btrfs_block_release(root, root->commit_root);
 471         free(root);
 472         printf("on close %llu blocks are allocated\n",
 473                (unsigned long long)allocated_bytes);
 474         return 0;
 475 }
 476
 477 void btrfs_block_release(struct btrfs_root *root, struct btrfs_buffer *buf)
 478 {
 479         buf->count--;
 480         if (buf->count < 0)
 481                 BUG();
 482         if (buf->count == 0) {
 483                 BUG_ON(!list_empty(&buf->cache));
 484                 BUG_ON(!list_empty(&buf->dirty));
 485                 if (!radix_tree_lookup(&root->fs_info->cache_radix,
 486                                        buf->bytenr))
 487                         BUG();
 488
 489                 radix_tree_delete(&root->fs_info->cache_radix, buf->bytenr);
 490                 BUG_ON(allocated_bytes == 0);
 491                 allocated_bytes -= buf->size;
 492                 BUG_ON(root->fs_info->cache_size == 0);
 493                 root->fs_info->cache_size -= buf->size;
 494
 495                 memset(buf, 0, sizeof(*buf));
 496                 free(buf);
 497         }
 498 }
 499