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