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 int btrfs_map_bh_to_logical(struct btrfs_root *root, struct btrfs_buffer *bh,
  19                              u64 logical)
  20 {
  21         bh->fd = root->fs_info->fp;
  22         bh->dev_blocknr = logical;
  23         return 0;
  24 }
  25
  26 static int check_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
  27 {
  28         if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
  29                 BUG();
  30         if (memcmp(root->fs_info->disk_super->fsid, buf->node.header.fsid,
  31                    sizeof(buf->node.header.fsid)))
  32                 BUG();
  33         return 0;
  34 }
  35
  36 static int free_some_buffers(struct btrfs_root *root)
  37 {
  38         struct list_head *node, *next;
  39         struct btrfs_buffer *b;
  40         if (root->fs_info->cache_size < cache_max)
  41                 return 0;
  42         list_for_each_safe(node, next, &root->fs_info->cache) {
  43                 b = list_entry(node, struct btrfs_buffer, cache);
  44                 if (b->count == 1) {
  45                         BUG_ON(!list_empty(&b->dirty));
  46                         list_del_init(&b->cache);
  47                         btrfs_block_release(root, b);
  48                         if (root->fs_info->cache_size < cache_max)
  49                                 break;
  50                 }
  51         }
  52         return 0;
  53 }
  54
  55 struct btrfs_buffer *alloc_tree_block(struct btrfs_root *root, u64 blocknr)
  56 {
  57         struct btrfs_buffer *buf;
  58         int ret;
  59
  60         buf = malloc(sizeof(struct btrfs_buffer) + root->blocksize);
  61         if (!buf)
  62                 return buf;
  63         allocated_blocks++;
  64         buf->blocknr = blocknr;
  65         buf->count = 2;
  66         INIT_LIST_HEAD(&buf->dirty);
  67         free_some_buffers(root);
  68         radix_tree_preload(GFP_KERNEL);
  69         ret = radix_tree_insert(&root->fs_info->cache_radix, blocknr, buf);
  70         radix_tree_preload_end();
  71         list_add_tail(&buf->cache, &root->fs_info->cache);
  72         root->fs_info->cache_size++;
  73         if (ret) {
  74                 free(buf);
  75                 return NULL;
  76         }
  77         return buf;
  78 }
  79
  80 struct btrfs_buffer *find_tree_block(struct btrfs_root *root, u64 blocknr)
  81 {
  82         struct btrfs_buffer *buf;
  83         buf = radix_tree_lookup(&root->fs_info->cache_radix, blocknr);
  84         if (buf) {
  85                 buf->count++;
  86         } else {
  87                 buf = alloc_tree_block(root, blocknr);
  88                 if (!buf) {
  89                         BUG();
  90                         return NULL;
  91                 }
  92         }
  93         return buf;
  94 }
  95
  96 struct btrfs_buffer *read_tree_block(struct btrfs_root *root, u64 blocknr)
  97 {
  98         struct btrfs_buffer *buf;
  99         int ret;
 100         buf = radix_tree_lookup(&root->fs_info->cache_radix, blocknr);
 101         if (buf) {
 102                 buf->count++;
 103                 if (check_tree_block(root, buf))
 104                         BUG();
 105         } else {
 106                 buf = alloc_tree_block(root, blocknr);
 107                 if (!buf)
 108                         return NULL;
 109                 btrfs_map_bh_to_logical(root, buf, blocknr);
 110                 ret = pread(buf->fd, &buf->node, root->blocksize,
 111                             buf->dev_blocknr * root->blocksize);
 112                 if (ret != root->blocksize) {
 113                         free(buf);
 114                         return NULL;
 115                 }
 116                 if (check_tree_block(root, buf))
 117                         BUG();
 118         }
 119         return buf;
 120 }
 121
 122 int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 123                      struct btrfs_buffer *buf)
 124 {
 125         if (!list_empty(&buf->dirty))
 126                 return 0;
 127         list_add_tail(&buf->dirty, &root->fs_info->trans);
 128         buf->count++;
 129         if (check_tree_block(root, buf))
 130                 BUG();
 131         return 0;
 132 }
 133
 134 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 135                      struct btrfs_buffer *buf)
 136 {
 137         if (!list_empty(&buf->dirty)) {
 138                 list_del_init(&buf->dirty);
 139                 btrfs_block_release(root, buf);
 140         }
 141         return 0;
 142 }
 143
 144 int write_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 145                      struct btrfs_buffer *buf)
 146 {
 147         int ret;
 148
 149         if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
 150                 BUG();
 151         btrfs_map_bh_to_logical(root, buf, buf->blocknr);
 152         if (check_tree_block(root, buf))
 153                 BUG();
 154         ret = pwrite(buf->fd, &buf->node, root->blocksize,
 155                      buf->dev_blocknr * root->blocksize);
 156         if (ret != root->blocksize)
 157                 return ret;
 158         return 0;
 159 }
 160
 161 static int __commit_transaction(struct btrfs_trans_handle *trans, struct
 162                                 btrfs_root *root)
 163 {
 164         struct btrfs_buffer *b;
 165         int ret = 0;
 166         int wret;
 167         while(!list_empty(&root->fs_info->trans)) {
 168                 b = list_entry(root->fs_info->trans.next, struct btrfs_buffer,
 169                                dirty);
 170                 list_del_init(&b->dirty);
 171                 wret = write_tree_block(trans, root, b);
 172                 if (wret)
 173                         ret = wret;
 174                 btrfs_block_release(root, b);
 175         }
 176         return ret;
 177 }
 178
 179 static int commit_tree_roots(struct btrfs_trans_handle *trans,
 180                              struct btrfs_fs_info *fs_info)
 181 {
 182         int ret;
 183         u64 old_extent_block;
 184         struct btrfs_root *tree_root = fs_info->tree_root;
 185         struct btrfs_root *extent_root = fs_info->extent_root;
 186
 187         btrfs_write_dirty_block_groups(trans, fs_info->extent_root);
 188         while(1) {
 189                 old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
 190                 if (old_extent_block == extent_root->node->blocknr)
 191                         break;
 192                 btrfs_set_root_blocknr(&extent_root->root_item,
 193                                        extent_root->node->blocknr);
 194                 ret = btrfs_update_root(trans, tree_root,
 195                                         &extent_root->root_key,
 196                                         &extent_root->root_item);
 197                 BUG_ON(ret);
 198                 btrfs_write_dirty_block_groups(trans, fs_info->extent_root);
 199         }
 200         return 0;
 201 }
 202
 203 int btrfs_commit_transaction(struct btrfs_trans_handle *trans, struct
 204                              btrfs_root *root, struct btrfs_super_block *s)
 205 {
 206         int ret = 0;
 207         struct btrfs_buffer *snap = root->commit_root;
 208         struct btrfs_key snap_key;
 209
 210         if (root->commit_root == root->node)
 211                 return 0;
 212
 213         memcpy(&snap_key, &root->root_key, sizeof(snap_key));
 214         root->root_key.offset++;
 215
 216         btrfs_set_root_blocknr(&root->root_item, root->node->blocknr);
 217         ret = btrfs_insert_root(trans, root->fs_info->tree_root,
 218                                 &root->root_key, &root->root_item);
 219         BUG_ON(ret);
 220
 221         ret = commit_tree_roots(trans, root->fs_info);
 222         BUG_ON(ret);
 223
 224         ret = __commit_transaction(trans, root);
 225         BUG_ON(ret);
 226
 227         write_ctree_super(trans, root, s);
 228         btrfs_finish_extent_commit(trans, root->fs_info->extent_root);
 229         btrfs_finish_extent_commit(trans, root->fs_info->tree_root);
 230
 231         root->commit_root = root->node;
 232         root->node->count++;
 233         ret = btrfs_drop_snapshot(trans, root, snap);
 234         BUG_ON(ret);
 235
 236         ret = btrfs_del_root(trans, root->fs_info->tree_root, &snap_key);
 237         BUG_ON(ret);
 238         root->fs_info->generation = root->root_key.offset + 1;
 239
 240         return ret;
 241 }
 242
 243 static int __setup_root(struct btrfs_super_block *super,
 244                         struct btrfs_root *root,
 245                         struct btrfs_fs_info *fs_info,
 246                         u64 objectid, int fp)
 247 {
 248         root->node = NULL;
 249         root->commit_root = NULL;
 250         root->blocksize = btrfs_super_blocksize(super);
 251         root->ref_cows = 0;
 252         root->fs_info = fs_info;
 253         memset(&root->root_key, 0, sizeof(root->root_key));
 254         memset(&root->root_item, 0, sizeof(root->root_item));
 255         root->root_key.objectid = objectid;
 256         return 0;
 257 }
 258
 259 static int find_and_setup_root(struct btrfs_super_block *super,
 260                                struct btrfs_root *tree_root,
 261                                struct btrfs_fs_info *fs_info,
 262                                u64 objectid,
 263                                struct btrfs_root *root, int fp)
 264 {
 265         int ret;
 266
 267         __setup_root(super, root, fs_info, objectid, fp);
 268         ret = btrfs_find_last_root(tree_root, objectid,
 269                                    &root->root_item, &root->root_key);
 270         BUG_ON(ret);
 271
 272         root->node = read_tree_block(root,
 273                                      btrfs_root_blocknr(&root->root_item));
 274         BUG_ON(!root->node);
 275         return 0;
 276 }
 277
 278 struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super)
 279 {
 280         int fp;
 281
 282         fp = open(filename, O_CREAT | O_RDWR, 0600);
 283         if (fp < 0) {
 284                 return NULL;
 285         }
 286         return open_ctree_fd(fp, super);
 287 }
 288
 289 struct btrfs_root *open_ctree_fd(int fp, struct btrfs_super_block *super)
 290 {
 291         struct btrfs_root *root = malloc(sizeof(struct btrfs_root));
 292         struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
 293         struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
 294         struct btrfs_fs_info *fs_info = malloc(sizeof(*fs_info));
 295         int ret;
 296
 297         INIT_RADIX_TREE(&fs_info->cache_radix, GFP_KERNEL);
 298         INIT_RADIX_TREE(&fs_info->pinned_radix, GFP_KERNEL);
 299         INIT_RADIX_TREE(&fs_info->block_group_radix, GFP_KERNEL);
 300         INIT_LIST_HEAD(&fs_info->trans);
 301         INIT_LIST_HEAD(&fs_info->cache);
 302         fs_info->cache_size = 0;
 303         fs_info->fp = fp;
 304         fs_info->running_transaction = NULL;
 305         fs_info->fs_root = root;
 306         fs_info->tree_root = tree_root;
 307         fs_info->extent_root = extent_root;
 308         fs_info->last_inode_alloc = 0;
 309         fs_info->last_inode_alloc_dirid = 0;
 310         fs_info->disk_super = super;
 311         memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
 312         memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
 313
 314         ret = pread(fp, super, sizeof(struct btrfs_super_block),
 315                      BTRFS_SUPER_INFO_OFFSET);
 316         if (ret == 0 || btrfs_super_root(super) == 0) {
 317                 BUG();
 318                 return NULL;
 319         }
 320         BUG_ON(ret < 0);
 321
 322         __setup_root(super, tree_root, fs_info, BTRFS_ROOT_TREE_OBJECTID, fp);
 323         tree_root->node = read_tree_block(tree_root, btrfs_super_root(super));
 324         BUG_ON(!tree_root->node);
 325
 326         ret = find_and_setup_root(super, tree_root, fs_info,
 327                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root, fp);
 328         BUG_ON(ret);
 329
 330         ret = find_and_setup_root(super, tree_root, fs_info,
 331                                   BTRFS_FS_TREE_OBJECTID, root, fp);
 332         BUG_ON(ret);
 333
 334         root->commit_root = root->node;
 335         root->node->count++;
 336         root->ref_cows = 1;
 337         root->fs_info->generation = root->root_key.offset + 1;
 338         btrfs_read_block_groups(root);
 339         return root;
 340 }
 341
 342 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
 343                       *root, struct btrfs_super_block *s)
 344 {
 345         int ret;
 346         btrfs_set_super_root(s, root->fs_info->tree_root->node->blocknr);
 347         ret = pwrite(root->fs_info->fp, s, sizeof(*s),
 348                      BTRFS_SUPER_INFO_OFFSET);
 349         if (ret != sizeof(*s)) {
 350                 fprintf(stderr, "failed to write new super block err %d\n", ret);
 351                 return ret;
 352         }
 353         return 0;
 354 }
 355
 356 static int drop_cache(struct btrfs_root *root)
 357 {
 358         while(!list_empty(&root->fs_info->cache)) {
 359                 struct btrfs_buffer *b = list_entry(root->fs_info->cache.next,
 360                                                     struct btrfs_buffer,
 361                                                     cache);
 362                 list_del_init(&b->cache);
 363                 btrfs_block_release(root, b);
 364         }
 365         return 0;
 366 }
 367
 368 int close_ctree(struct btrfs_root *root, struct btrfs_super_block *s)
 369 {
 370         int ret;
 371         struct btrfs_trans_handle *trans;
 372
 373         trans = root->fs_info->running_transaction;
 374         btrfs_commit_transaction(trans, root, s);
 375         ret = commit_tree_roots(trans, root->fs_info);
 376         BUG_ON(ret);
 377         ret = __commit_transaction(trans, root);
 378         BUG_ON(ret);
 379         write_ctree_super(trans, root, s);
 380         drop_cache(root);
 381         BUG_ON(!list_empty(&root->fs_info->trans));
 382
 383         btrfs_free_block_groups(root->fs_info);
 384         close(root->fs_info->fp);
 385         if (root->node)
 386                 btrfs_block_release(root, root->node);
 387         if (root->fs_info->extent_root->node)
 388                 btrfs_block_release(root->fs_info->extent_root,
 389                                     root->fs_info->extent_root->node);
 390         if (root->fs_info->tree_root->node)
 391                 btrfs_block_release(root->fs_info->tree_root,
 392                                     root->fs_info->tree_root->node);
 393         btrfs_block_release(root, root->commit_root);
 394         free(root);
 395         printf("on close %d blocks are allocated\n", allocated_blocks);
 396         return 0;
 397 }
 398
 399 void btrfs_block_release(struct btrfs_root *root, struct btrfs_buffer *buf)
 400 {
 401         buf->count--;
 402         if (buf->count < 0)
 403                 BUG();
 404         if (buf->count == 0) {
 405                 BUG_ON(!list_empty(&buf->cache));
 406                 BUG_ON(!list_empty(&buf->dirty));
 407                 if (!radix_tree_lookup(&root->fs_info->cache_radix,
 408                                        buf->blocknr))
 409                         BUG();
 410                 radix_tree_delete(&root->fs_info->cache_radix, buf->blocknr);
 411                 memset(buf, 0, sizeof(*buf));
 412                 free(buf);
 413                 BUG_ON(allocated_blocks == 0);
 414                 allocated_blocks--;
 415                 BUG_ON(root->fs_info->cache_size == 0);
 416                 root->fs_info->cache_size--;
 417         }
 418 }
 419