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->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         struct btrfs_root *root = malloc(sizeof(struct btrfs_root));
 271         struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
 272         struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
 273         struct btrfs_root *inode_root = malloc(sizeof(struct btrfs_root));
 274         struct btrfs_fs_info *fs_info = malloc(sizeof(*fs_info));
 275         int fp;
 276         int ret;
 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(&fs_info->cache_radix, GFP_KERNEL);
 284         INIT_RADIX_TREE(&fs_info->pinned_radix, GFP_KERNEL);
 285         INIT_LIST_HEAD(&fs_info->trans);
 286         INIT_LIST_HEAD(&fs_info->cache);
 287         fs_info->cache_size = 0;
 288         fs_info->fp = fp;
 289         fs_info->running_transaction = NULL;
 290         fs_info->fs_root = root;
 291         fs_info->tree_root = tree_root;
 292         fs_info->extent_root = extent_root;
 293         fs_info->inode_root = inode_root;
 294         fs_info->last_inode_alloc = 0;
 295         fs_info->last_inode_alloc_dirid = 0;
 296         fs_info->disk_super = super;
 297         memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
 298         memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
 299
 300         ret = pread(fp, super, sizeof(struct btrfs_super_block),
 301                      BTRFS_SUPER_INFO_OFFSET);
 302         if (ret == 0 || btrfs_super_root(super) == 0) {
 303                 BUG();
 304                 return NULL;
 305         }
 306         BUG_ON(ret < 0);
 307
 308         __setup_root(super, tree_root, fs_info, BTRFS_ROOT_TREE_OBJECTID, fp);
 309         tree_root->node = read_tree_block(tree_root, btrfs_super_root(super));
 310         BUG_ON(!tree_root->node);
 311
 312         ret = find_and_setup_root(super, tree_root, fs_info,
 313                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root, fp);
 314         BUG_ON(ret);
 315
 316         ret = find_and_setup_root(super, tree_root, fs_info,
 317                                   BTRFS_INODE_MAP_OBJECTID, inode_root, fp);
 318         BUG_ON(ret);
 319
 320         ret = find_and_setup_root(super, tree_root, fs_info,
 321                                   BTRFS_FS_TREE_OBJECTID, root, fp);
 322         BUG_ON(ret);
 323
 324         root->commit_root = root->node;
 325         root->node->count++;
 326         root->ref_cows = 1;
 327         root->fs_info->generation = root->root_key.offset + 1;
 328         return root;
 329 }
 330
 331 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
 332                       *root, struct btrfs_super_block *s)
 333 {
 334         int ret;
 335         btrfs_set_super_root(s, root->fs_info->tree_root->node->blocknr);
 336         ret = pwrite(root->fs_info->fp, s, sizeof(*s),
 337                      BTRFS_SUPER_INFO_OFFSET);
 338         if (ret != sizeof(*s)) {
 339                 fprintf(stderr, "failed to write new super block err %d\n", ret);
 340                 return ret;
 341         }
 342         return 0;
 343 }
 344
 345 static int drop_cache(struct btrfs_root *root)
 346 {
 347         while(!list_empty(&root->fs_info->cache)) {
 348                 struct btrfs_buffer *b = list_entry(root->fs_info->cache.next,
 349                                                     struct btrfs_buffer,
 350                                                     cache);
 351                 list_del_init(&b->cache);
 352                 btrfs_block_release(root, b);
 353         }
 354         return 0;
 355 }
 356 int close_ctree(struct btrfs_root *root, struct btrfs_super_block *s)
 357 {
 358         int ret;
 359         struct btrfs_trans_handle *trans;
 360
 361         trans = root->fs_info->running_transaction;
 362         btrfs_commit_transaction(trans, root, s);
 363         ret = commit_tree_roots(trans, root->fs_info);
 364         BUG_ON(ret);
 365         ret = __commit_transaction(trans, root);
 366         BUG_ON(ret);
 367         write_ctree_super(trans, root, s);
 368         drop_cache(root);
 369         BUG_ON(!list_empty(&root->fs_info->trans));
 370
 371         close(root->fs_info->fp);
 372         if (root->node)
 373                 btrfs_block_release(root, root->node);
 374         if (root->fs_info->extent_root->node)
 375                 btrfs_block_release(root->fs_info->extent_root,
 376                                     root->fs_info->extent_root->node);
 377         if (root->fs_info->inode_root->node)
 378                 btrfs_block_release(root->fs_info->inode_root,
 379                                     root->fs_info->inode_root->node);
 380         if (root->fs_info->tree_root->node)
 381                 btrfs_block_release(root->fs_info->tree_root,
 382                                     root->fs_info->tree_root->node);
 383         btrfs_block_release(root, root->commit_root);
 384         free(root);
 385         printf("on close %d blocks are allocated\n", allocated_blocks);
 386         return 0;
 387 }
 388
 389 void btrfs_block_release(struct btrfs_root *root, struct btrfs_buffer *buf)
 390 {
 391         buf->count--;
 392         if (buf->count < 0)
 393                 BUG();
 394         if (buf->count == 0) {
 395                 BUG_ON(!list_empty(&buf->cache));
 396                 BUG_ON(!list_empty(&buf->dirty));
 397                 if (!radix_tree_lookup(&root->fs_info->cache_radix,
 398                                        buf->blocknr))
 399                         BUG();
 400                 radix_tree_delete(&root->fs_info->cache_radix, buf->blocknr);
 401                 memset(buf, 0, sizeof(*buf));
 402                 free(buf);
 403                 BUG_ON(allocated_blocks == 0);
 404                 allocated_blocks--;
 405                 BUG_ON(root->fs_info->cache_size == 0);
 406                 root->fs_info->cache_size--;
 407         }
 408 }
 409