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 static int check_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
  18 {
  19         if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
  20                 BUG();
  21         if (memcmp(root->fs_info->disk_super->fsid, buf->node.header.fsid,
  22                    sizeof(buf->node.header.fsid)))
  23                 BUG();
  24         return 0;
  25 }
  26
  27 static int free_some_buffers(struct btrfs_root *root)
  28 {
  29         struct list_head *node, *next;
  30         struct btrfs_buffer *b;
  31         if (root->fs_info->cache_size < cache_max)
  32                 return 0;
  33         list_for_each_safe(node, next, &root->fs_info->cache) {
  34                 b = list_entry(node, struct btrfs_buffer, cache);
  35                 if (b->count == 1) {
  36                         BUG_ON(!list_empty(&b->dirty));
  37                         list_del_init(&b->cache);
  38                         btrfs_block_release(root, b);
  39                         if (root->fs_info->cache_size < cache_max)
  40                                 break;
  41                 }
  42         }
  43         return 0;
  44 }
  45
  46 struct btrfs_buffer *alloc_tree_block(struct btrfs_root *root, u64 blocknr)
  47 {
  48         struct btrfs_buffer *buf;
  49         int ret;
  50
  51         buf = malloc(sizeof(struct btrfs_buffer) + root->blocksize);
  52         if (!buf)
  53                 return buf;
  54         allocated_blocks++;
  55         buf->blocknr = blocknr;
  56         buf->count = 2;
  57         INIT_LIST_HEAD(&buf->dirty);
  58         free_some_buffers(root);
  59         radix_tree_preload(GFP_KERNEL);
  60         ret = radix_tree_insert(&root->fs_info->cache_radix, blocknr, buf);
  61         radix_tree_preload_end();
  62         list_add_tail(&buf->cache, &root->fs_info->cache);
  63         root->fs_info->cache_size++;
  64         if (ret) {
  65                 free(buf);
  66                 return NULL;
  67         }
  68         return buf;
  69 }
  70
  71 struct btrfs_buffer *find_tree_block(struct btrfs_root *root, u64 blocknr)
  72 {
  73         struct btrfs_buffer *buf;
  74         buf = radix_tree_lookup(&root->fs_info->cache_radix, blocknr);
  75         if (buf) {
  76                 buf->count++;
  77         } else {
  78                 buf = alloc_tree_block(root, blocknr);
  79                 if (!buf) {
  80                         BUG();
  81                         return NULL;
  82                 }
  83         }
  84         return buf;
  85 }
  86
  87 struct btrfs_buffer *read_tree_block(struct btrfs_root *root, u64 blocknr)
  88 {
  89         loff_t offset = blocknr * root->blocksize;
  90         struct btrfs_buffer *buf;
  91         int ret;
  92         buf = radix_tree_lookup(&root->fs_info->cache_radix, blocknr);
  93         if (buf) {
  94                 buf->count++;
  95         } else {
  96                 buf = alloc_tree_block(root, blocknr);
  97                 if (!buf)
  98                         return NULL;
  99                 ret = pread(root->fs_info->fp, &buf->node, root->blocksize,
 100                             offset);
 101                 if (ret != root->blocksize) {
 102                         free(buf);
 103                         return NULL;
 104                 }
 105         }
 106         if (check_tree_block(root, buf))
 107                 BUG();
 108         return buf;
 109 }
 110
 111 int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 112                      struct btrfs_buffer *buf)
 113 {
 114         if (!list_empty(&buf->dirty))
 115                 return 0;
 116         list_add_tail(&buf->dirty, &root->fs_info->trans);
 117         buf->count++;
 118         return 0;
 119 }
 120
 121 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 122                      struct btrfs_buffer *buf)
 123 {
 124         if (!list_empty(&buf->dirty)) {
 125                 list_del_init(&buf->dirty);
 126                 btrfs_block_release(root, buf);
 127         }
 128         return 0;
 129 }
 130
 131 int write_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 132                      struct btrfs_buffer *buf)
 133 {
 134         u64 blocknr = buf->blocknr;
 135         loff_t offset = blocknr * root->blocksize;
 136         int ret;
 137
 138         if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
 139                 BUG();
 140         ret = pwrite(root->fs_info->fp, &buf->node, root->blocksize, offset);
 141         if (ret != root->blocksize)
 142                 return ret;
 143         return 0;
 144 }
 145
 146 static int __commit_transaction(struct btrfs_trans_handle *trans, struct
 147                                 btrfs_root *root)
 148 {
 149         struct btrfs_buffer *b;
 150         int ret = 0;
 151         int wret;
 152         while(!list_empty(&root->fs_info->trans)) {
 153                 b = list_entry(root->fs_info->trans.next, struct btrfs_buffer,
 154                                dirty);
 155                 list_del_init(&b->dirty);
 156                 wret = write_tree_block(trans, root, b);
 157                 if (wret)
 158                         ret = wret;
 159                 btrfs_block_release(root, b);
 160         }
 161         return ret;
 162 }
 163
 164 static int commit_tree_roots(struct btrfs_trans_handle *trans,
 165                              struct btrfs_fs_info *fs_info)
 166 {
 167         int ret;
 168         u64 old_extent_block;
 169         struct btrfs_root *tree_root = fs_info->tree_root;
 170         struct btrfs_root *extent_root = fs_info->extent_root;
 171
 172         while(1) {
 173                 old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
 174                 if (old_extent_block == extent_root->node->blocknr)
 175                         break;
 176                 btrfs_set_root_blocknr(&extent_root->root_item,
 177                                        extent_root->node->blocknr);
 178                 ret = btrfs_update_root(trans, tree_root,
 179                                         &extent_root->root_key,
 180                                         &extent_root->root_item);
 181                 BUG_ON(ret);
 182         }
 183         return 0;
 184 }
 185
 186 int btrfs_commit_transaction(struct btrfs_trans_handle *trans, struct
 187                              btrfs_root *root, struct btrfs_super_block *s)
 188 {
 189         int ret = 0;
 190         struct btrfs_buffer *snap = root->commit_root;
 191         struct btrfs_key snap_key;
 192
 193         if (root->commit_root == root->node)
 194                 return 0;
 195
 196         memcpy(&snap_key, &root->root_key, sizeof(snap_key));
 197         root->root_key.offset++;
 198
 199         btrfs_set_root_blocknr(&root->root_item, root->node->blocknr);
 200         ret = btrfs_insert_root(trans, root->fs_info->tree_root,
 201                                 &root->root_key, &root->root_item);
 202         BUG_ON(ret);
 203
 204         ret = commit_tree_roots(trans, root->fs_info);
 205         BUG_ON(ret);
 206
 207         ret = __commit_transaction(trans, root);
 208         BUG_ON(ret);
 209
 210         write_ctree_super(trans, root, s);
 211         btrfs_finish_extent_commit(trans, root->fs_info->extent_root);
 212         btrfs_finish_extent_commit(trans, root->fs_info->tree_root);
 213
 214         root->commit_root = root->node;
 215         root->node->count++;
 216         ret = btrfs_drop_snapshot(trans, root, snap);
 217         BUG_ON(ret);
 218
 219         ret = btrfs_del_root(trans, root->fs_info->tree_root, &snap_key);
 220         BUG_ON(ret);
 221         root->fs_info->generation = root->root_key.offset + 1;
 222
 223         return ret;
 224 }
 225
 226 static int __setup_root(struct btrfs_super_block *super,
 227                         struct btrfs_root *root,
 228                         struct btrfs_fs_info *fs_info,
 229                         u64 objectid, int fp)
 230 {
 231         root->node = NULL;
 232         root->commit_root = NULL;
 233         root->blocksize = btrfs_super_blocksize(super);
 234         root->ref_cows = 0;
 235         root->fs_info = fs_info;
 236         memset(&root->root_key, 0, sizeof(root->root_key));
 237         memset(&root->root_item, 0, sizeof(root->root_item));
 238         return 0;
 239 }
 240
 241 static int find_and_setup_root(struct btrfs_super_block *super,
 242                                struct btrfs_root *tree_root,
 243                                struct btrfs_fs_info *fs_info,
 244                                u64 objectid,
 245                                struct btrfs_root *root, int fp)
 246 {
 247         int ret;
 248
 249         __setup_root(super, root, fs_info, objectid, fp);
 250         ret = btrfs_find_last_root(tree_root, objectid,
 251                                    &root->root_item, &root->root_key);
 252         BUG_ON(ret);
 253
 254         root->node = read_tree_block(root,
 255                                      btrfs_root_blocknr(&root->root_item));
 256         BUG_ON(!root->node);
 257         return 0;
 258 }
 259
 260 struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super)
 261 {
 262         int fp;
 263
 264         fp = open(filename, O_CREAT | O_RDWR, 0600);
 265         if (fp < 0) {
 266                 return NULL;
 267         }
 268         return open_ctree_fd(fp, super);
 269 }
 270
 271 struct btrfs_root *open_ctree_fd(int fp, struct btrfs_super_block *super)
 272 {
 273         struct btrfs_root *root = malloc(sizeof(struct btrfs_root));
 274         struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
 275         struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
 276         struct btrfs_fs_info *fs_info = malloc(sizeof(*fs_info));
 277         int ret;
 278
 279         INIT_RADIX_TREE(&fs_info->cache_radix, GFP_KERNEL);
 280         INIT_RADIX_TREE(&fs_info->pinned_radix, GFP_KERNEL);
 281         INIT_LIST_HEAD(&fs_info->trans);
 282         INIT_LIST_HEAD(&fs_info->cache);
 283         fs_info->cache_size = 0;
 284         fs_info->fp = fp;
 285         fs_info->running_transaction = NULL;
 286         fs_info->fs_root = root;
 287         fs_info->tree_root = tree_root;
 288         fs_info->extent_root = extent_root;
 289         fs_info->last_inode_alloc = 0;
 290         fs_info->last_inode_alloc_dirid = 0;
 291         fs_info->disk_super = super;
 292         memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
 293         memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
 294
 295         ret = pread(fp, super, sizeof(struct btrfs_super_block),
 296                      BTRFS_SUPER_INFO_OFFSET);
 297         if (ret == 0 || btrfs_super_root(super) == 0) {
 298                 BUG();
 299                 return NULL;
 300         }
 301         BUG_ON(ret < 0);
 302         __setup_root(super, tree_root, fs_info, BTRFS_ROOT_TREE_OBJECTID, fp);
 303         tree_root->node = read_tree_block(tree_root, btrfs_super_root(super));
 304         BUG_ON(!tree_root->node);
 305
 306         ret = find_and_setup_root(super, tree_root, fs_info,
 307                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root, fp);
 308         BUG_ON(ret);
 309
 310         ret = find_and_setup_root(super, tree_root, fs_info,
 311                                   BTRFS_FS_TREE_OBJECTID, root, fp);
 312         BUG_ON(ret);
 313
 314         root->commit_root = root->node;
 315         root->node->count++;
 316         root->ref_cows = 1;
 317         root->fs_info->generation = root->root_key.offset + 1;
 318         return root;
 319 }
 320
 321 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
 322                       *root, struct btrfs_super_block *s)
 323 {
 324         int ret;
 325         btrfs_set_super_root(s, root->fs_info->tree_root->node->blocknr);
 326         ret = pwrite(root->fs_info->fp, s, sizeof(*s),
 327                      BTRFS_SUPER_INFO_OFFSET);
 328         if (ret != sizeof(*s)) {
 329                 fprintf(stderr, "failed to write new super block err %d\n", ret);
 330                 return ret;
 331         }
 332         return 0;
 333 }
 334
 335 static int drop_cache(struct btrfs_root *root)
 336 {
 337         while(!list_empty(&root->fs_info->cache)) {
 338                 struct btrfs_buffer *b = list_entry(root->fs_info->cache.next,
 339                                                     struct btrfs_buffer,
 340                                                     cache);
 341                 list_del_init(&b->cache);
 342                 btrfs_block_release(root, b);
 343         }
 344         return 0;
 345 }
 346 int close_ctree(struct btrfs_root *root, struct btrfs_super_block *s)
 347 {
 348         int ret;
 349         struct btrfs_trans_handle *trans;
 350
 351         trans = root->fs_info->running_transaction;
 352         btrfs_commit_transaction(trans, root, s);
 353         ret = commit_tree_roots(trans, root->fs_info);
 354         BUG_ON(ret);
 355         ret = __commit_transaction(trans, root);
 356         BUG_ON(ret);
 357         write_ctree_super(trans, root, s);
 358         drop_cache(root);
 359         BUG_ON(!list_empty(&root->fs_info->trans));
 360
 361         close(root->fs_info->fp);
 362         if (root->node)
 363                 btrfs_block_release(root, root->node);
 364         if (root->fs_info->extent_root->node)
 365                 btrfs_block_release(root->fs_info->extent_root,
 366                                     root->fs_info->extent_root->node);
 367         if (root->fs_info->tree_root->node)
 368                 btrfs_block_release(root->fs_info->tree_root,
 369                                     root->fs_info->tree_root->node);
 370         btrfs_block_release(root, root->commit_root);
 371         free(root);
 372         printf("on close %d blocks are allocated\n", allocated_blocks);
 373         return 0;
 374 }
 375
 376 void btrfs_block_release(struct btrfs_root *root, struct btrfs_buffer *buf)
 377 {
 378         buf->count--;
 379         if (buf->count < 0)
 380                 BUG();
 381         if (buf->count == 0) {
 382                 BUG_ON(!list_empty(&buf->cache));
 383                 BUG_ON(!list_empty(&buf->dirty));
 384                 if (!radix_tree_lookup(&root->fs_info->cache_radix,
 385                                        buf->blocknr))
 386                         BUG();
 387                 radix_tree_delete(&root->fs_info->cache_radix, buf->blocknr);
 388                 memset(buf, 0, sizeof(*buf));
 389                 free(buf);
 390                 BUG_ON(allocated_blocks == 0);
 391                 allocated_blocks--;
 392                 BUG_ON(root->fs_info->cache_size == 0);
 393                 root->fs_info->cache_size--;
 394         }
 395 }
 396