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 (root->node && btrfs_header_parentid(&buf->node.header) !=
  22             btrfs_header_parentid(&root->node->node.header))
  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->cache_size < cache_max)
  32                 return 0;
  33         list_for_each_safe(node, next, &root->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->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->cache_radix, blocknr, buf);
  61         radix_tree_preload_end();
  62         list_add_tail(&buf->cache, &root->cache);
  63         root->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->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->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->fp, &buf->node, root->blocksize, 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->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->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->trans)) {
 153                 b = list_entry(root->trans.next, struct btrfs_buffer, dirty);
 154                 list_del_init(&b->dirty);
 155                 wret = write_tree_block(trans, root, b);
 156                 if (wret)
 157                         ret = wret;
 158                 btrfs_block_release(root, b);
 159         }
 160         return ret;
 161 }
 162
 163 static int commit_extent_and_tree_roots(struct btrfs_trans_handle *trans,
 164                                         struct btrfs_root *tree_root, struct
 165                                         btrfs_root *extent_root)
 166 {
 167         int ret;
 168         u64 old_extent_block;
 169
 170         while(1) {
 171                 old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
 172                 if (old_extent_block == extent_root->node->blocknr)
 173                         break;
 174                 btrfs_set_root_blocknr(&extent_root->root_item,
 175                                        extent_root->node->blocknr);
 176                 ret = btrfs_update_root(trans, tree_root,
 177                                         &extent_root->root_key,
 178                                         &extent_root->root_item);
 179                 BUG_ON(ret);
 180         }
 181         __commit_transaction(trans, extent_root);
 182         __commit_transaction(trans, tree_root);
 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         ret = __commit_transaction(trans, root);
 194         BUG_ON(ret);
 195
 196         if (root->commit_root == root->node)
 197                 return 0;
 198
 199         memcpy(&snap_key, &root->root_key, sizeof(snap_key));
 200         root->root_key.offset++;
 201
 202         btrfs_set_root_blocknr(&root->root_item, root->node->blocknr);
 203         ret = btrfs_insert_root(trans, root->tree_root, &root->root_key,
 204                                 &root->root_item);
 205         BUG_ON(ret);
 206
 207         ret = commit_extent_and_tree_roots(trans, root->tree_root,
 208                                            root->extent_root);
 209         BUG_ON(ret);
 210
 211         write_ctree_super(trans, root, s);
 212         btrfs_finish_extent_commit(trans, root->extent_root);
 213         btrfs_finish_extent_commit(trans, root->tree_root);
 214
 215         root->commit_root = root->node;
 216         root->node->count++;
 217         ret = btrfs_drop_snapshot(trans, root, snap);
 218         BUG_ON(ret);
 219
 220         ret = btrfs_del_root(trans, root->tree_root, &snap_key);
 221         BUG_ON(ret);
 222
 223         return ret;
 224 }
 225
 226 static int __setup_root(struct btrfs_super_block *super,
 227                         struct btrfs_root *root, u64 objectid, int fp)
 228 {
 229         INIT_LIST_HEAD(&root->trans);
 230         INIT_LIST_HEAD(&root->cache);
 231         root->cache_size = 0;
 232         root->fp = fp;
 233         root->node = NULL;
 234         root->commit_root = NULL;
 235         root->blocksize = btrfs_super_blocksize(super);
 236         root->ref_cows = 0;
 237         memset(&root->current_insert, 0, sizeof(root->current_insert));
 238         memset(&root->last_insert, 0, sizeof(root->last_insert));
 239         memset(&root->root_key, 0, sizeof(root->root_key));
 240         memset(&root->root_item, 0, sizeof(root->root_item));
 241         return 0;
 242 }
 243
 244 static int find_and_setup_root(struct btrfs_super_block *super,
 245                                struct btrfs_root *tree_root, u64 objectid,
 246                                struct btrfs_root *root, int fp)
 247 {
 248         int ret;
 249
 250         __setup_root(super, root, objectid, fp);
 251         ret = btrfs_find_last_root(tree_root, objectid,
 252                                    &root->root_item, &root->root_key);
 253         BUG_ON(ret);
 254
 255         root->node = read_tree_block(root,
 256                                      btrfs_root_blocknr(&root->root_item));
 257         BUG_ON(!root->node);
 258         return 0;
 259 }
 260
 261 struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super)
 262 {
 263         struct btrfs_root *root = malloc(sizeof(struct btrfs_root));
 264         struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
 265         struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
 266         int fp;
 267         int ret;
 268
 269         root->extent_root = extent_root;
 270         root->tree_root = tree_root;
 271
 272         extent_root->extent_root = extent_root;
 273         extent_root->tree_root = tree_root;
 274
 275         tree_root->extent_root = extent_root;
 276         tree_root->tree_root = tree_root;
 277
 278         fp = open(filename, O_CREAT | O_RDWR, 0600);
 279         if (fp < 0) {
 280                 free(root);
 281                 return NULL;
 282         }
 283         INIT_RADIX_TREE(&root->cache_radix, GFP_KERNEL);
 284         INIT_RADIX_TREE(&root->pinned_radix, GFP_KERNEL);
 285         INIT_RADIX_TREE(&extent_root->pinned_radix, GFP_KERNEL);
 286         INIT_RADIX_TREE(&extent_root->cache_radix, GFP_KERNEL);
 287         INIT_RADIX_TREE(&tree_root->pinned_radix, GFP_KERNEL);
 288         INIT_RADIX_TREE(&tree_root->cache_radix, GFP_KERNEL);
 289
 290         ret = pread(fp, super, sizeof(struct btrfs_super_block),
 291                      BTRFS_SUPER_INFO_OFFSET);
 292         if (ret == 0 || btrfs_super_root(super) == 0) {
 293                 printf("making new FS!\n");
 294                 ret = mkfs(fp, 0, 1024);
 295                 if (ret)
 296                         return NULL;
 297                 ret = pread(fp, super, sizeof(struct btrfs_super_block),
 298                              BTRFS_SUPER_INFO_OFFSET);
 299                 if (ret != sizeof(struct btrfs_super_block))
 300                         return NULL;
 301         }
 302         BUG_ON(ret < 0);
 303
 304         __setup_root(super, tree_root, BTRFS_ROOT_TREE_OBJECTID, fp);
 305         tree_root->node = read_tree_block(tree_root, btrfs_super_root(super));
 306         BUG_ON(!tree_root->node);
 307
 308         ret = find_and_setup_root(super, tree_root, BTRFS_EXTENT_TREE_OBJECTID,
 309                                   extent_root, fp);
 310         BUG_ON(ret);
 311
 312         ret = find_and_setup_root(super, tree_root, BTRFS_FS_TREE_OBJECTID,
 313                                   root, fp);
 314         BUG_ON(ret);
 315
 316         root->commit_root = root->node;
 317         root->node->count++;
 318         root->ref_cows = 1;
 319         return root;
 320 }
 321
 322 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
 323                       *root, struct btrfs_super_block *s)
 324 {
 325         int ret;
 326         btrfs_set_super_root(s, root->tree_root->node->blocknr);
 327         ret = pwrite(root->fp, s, sizeof(*s),
 328                      BTRFS_SUPER_INFO_OFFSET);
 329         if (ret != sizeof(*s)) {
 330                 fprintf(stderr, "failed to write new super block err %d\n", ret);
 331                 return ret;
 332         }
 333         return 0;
 334 }
 335
 336 static int drop_cache(struct btrfs_root *root)
 337 {
 338         while(!list_empty(&root->cache)) {
 339                 struct btrfs_buffer *b = list_entry(root->cache.next,
 340                                                    struct btrfs_buffer, 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->running_transaction;
 352         btrfs_commit_transaction(trans, root, s);
 353         ret = commit_extent_and_tree_roots(trans, root->tree_root,
 354                                            root->extent_root);
 355         BUG_ON(ret);
 356         write_ctree_super(trans, root, s);
 357         drop_cache(root->extent_root);
 358         drop_cache(root->tree_root);
 359         drop_cache(root);
 360         BUG_ON(!list_empty(&root->trans));
 361         BUG_ON(!list_empty(&root->extent_root->trans));
 362         BUG_ON(!list_empty(&root->tree_root->trans));
 363
 364         close(root->fp);
 365         if (root->node)
 366                 btrfs_block_release(root, root->node);
 367         if (root->extent_root->node)
 368                 btrfs_block_release(root->extent_root, root->extent_root->node);
 369         if (root->tree_root->node)
 370                 btrfs_block_release(root->tree_root, root->tree_root->node);
 371         btrfs_block_release(root, root->commit_root);
 372         free(root);
 373         printf("on close %d blocks are allocated\n", allocated_blocks);
 374         return 0;
 375 }
 376
 377 void btrfs_block_release(struct btrfs_root *root, struct btrfs_buffer *buf)
 378 {
 379         buf->count--;
 380         if (buf->count < 0)
 381                 BUG();
 382         if (buf->count == 0) {
 383                 BUG_ON(!list_empty(&buf->cache));
 384                 BUG_ON(!list_empty(&buf->dirty));
 385                 if (!radix_tree_lookup(&root->cache_radix, buf->blocknr))
 386                         BUG();
 387                 radix_tree_delete(&root->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->cache_size == 0);
 393                 root->cache_size--;
 394         }
 395 }
 396