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
  13 static int allocated_blocks = 0;
  14 int cache_max = 10000;
  15
  16 static int check_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
  17 {
  18         if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
  19                 BUG();
  20         if (root->node && btrfs_header_parentid(&buf->node.header) !=
  21             btrfs_header_parentid(&root->node->node.header))
  22                 BUG();
  23         return 0;
  24 }
  25
  26 static int free_some_buffers(struct btrfs_root *root)
  27 {
  28         struct list_head *node, *next;
  29         struct btrfs_buffer *b;
  30         if (root->cache_size < cache_max)
  31                 return 0;
  32         list_for_each_safe(node, next, &root->cache) {
  33                 b = list_entry(node, struct btrfs_buffer, cache);
  34                 if (b->count == 1) {
  35                         BUG_ON(!list_empty(&b->dirty));
  36                         list_del_init(&b->cache);
  37                         btrfs_block_release(root, b);
  38                         if (root->cache_size < cache_max)
  39                                 break;
  40                 }
  41         }
  42         return 0;
  43 }
  44
  45 struct btrfs_buffer *alloc_tree_block(struct btrfs_root *root, u64 blocknr)
  46 {
  47         struct btrfs_buffer *buf;
  48         int ret;
  49
  50         buf = malloc(sizeof(struct btrfs_buffer) + root->blocksize);
  51         if (!buf)
  52                 return buf;
  53         allocated_blocks++;
  54         buf->blocknr = blocknr;
  55         buf->count = 2;
  56         INIT_LIST_HEAD(&buf->dirty);
  57         free_some_buffers(root);
  58         radix_tree_preload(GFP_KERNEL);
  59         ret = radix_tree_insert(&root->cache_radix, blocknr, buf);
  60         radix_tree_preload_end();
  61         list_add_tail(&buf->cache, &root->cache);
  62         root->cache_size++;
  63         if (ret) {
  64                 free(buf);
  65                 return NULL;
  66         }
  67         return buf;
  68 }
  69
  70 struct btrfs_buffer *find_tree_block(struct btrfs_root *root, u64 blocknr)
  71 {
  72         struct btrfs_buffer *buf;
  73         buf = radix_tree_lookup(&root->cache_radix, blocknr);
  74         if (buf) {
  75                 buf->count++;
  76         } else {
  77                 buf = alloc_tree_block(root, blocknr);
  78                 if (!buf) {
  79                         BUG();
  80                         return NULL;
  81                 }
  82         }
  83         return buf;
  84 }
  85
  86 struct btrfs_buffer *read_tree_block(struct btrfs_root *root, u64 blocknr)
  87 {
  88         loff_t offset = blocknr * root->blocksize;
  89         struct btrfs_buffer *buf;
  90         int ret;
  91
  92         buf = radix_tree_lookup(&root->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->fp, &buf->node, root->blocksize, offset);
 100                 if (ret != root->blocksize) {
 101                         free(buf);
 102                         return NULL;
 103                 }
 104         }
 105         if (check_tree_block(root, buf))
 106                 BUG();
 107         return buf;
 108 }
 109
 110 int dirty_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
 111 {
 112         if (!list_empty(&buf->dirty))
 113                 return 0;
 114         list_add_tail(&buf->dirty, &root->trans);
 115         buf->count++;
 116         return 0;
 117 }
 118
 119 int clean_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
 120 {
 121         if (!list_empty(&buf->dirty)) {
 122                 list_del_init(&buf->dirty);
 123                 btrfs_block_release(root, buf);
 124         }
 125         return 0;
 126 }
 127
 128 int write_tree_block(struct btrfs_root *root, struct btrfs_buffer *buf)
 129 {
 130         u64 blocknr = buf->blocknr;
 131         loff_t offset = blocknr * root->blocksize;
 132         int ret;
 133
 134         if (buf->blocknr != btrfs_header_blocknr(&buf->node.header))
 135                 BUG();
 136         ret = pwrite(root->fp, &buf->node, root->blocksize, offset);
 137         if (ret != root->blocksize)
 138                 return ret;
 139         return 0;
 140 }
 141
 142 static int __commit_transaction(struct btrfs_root *root)
 143 {
 144         struct btrfs_buffer *b;
 145         int ret = 0;
 146         int wret;
 147         while(!list_empty(&root->trans)) {
 148                 b = list_entry(root->trans.next, struct btrfs_buffer, dirty);
 149                 list_del_init(&b->dirty);
 150                 wret = write_tree_block(root, b);
 151                 if (wret)
 152                         ret = wret;
 153                 btrfs_block_release(root, b);
 154         }
 155         return ret;
 156 }
 157
 158 static int commit_extent_and_tree_roots(struct btrfs_root *tree_root,
 159                                         struct btrfs_root *extent_root)
 160 {
 161         int ret;
 162         u64 old_extent_block;
 163
 164         while(1) {
 165                 old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
 166                 if (old_extent_block == extent_root->node->blocknr)
 167                         break;
 168                 btrfs_set_root_blocknr(&extent_root->root_item,
 169                                        extent_root->node->blocknr);
 170                 ret = btrfs_update_root(tree_root,
 171                                         &extent_root->root_key,
 172                                         &extent_root->root_item);
 173                 BUG_ON(ret);
 174         }
 175         __commit_transaction(extent_root);
 176         __commit_transaction(tree_root);
 177         return 0;
 178 }
 179
 180 int btrfs_commit_transaction(struct btrfs_root *root,
 181                              struct btrfs_super_block *s)
 182 {
 183         int ret = 0;
 184         struct btrfs_buffer *snap = root->commit_root;
 185         struct btrfs_key snap_key;
 186
 187         ret = __commit_transaction(root);
 188         BUG_ON(ret);
 189
 190         if (root->commit_root == root->node)
 191                 return 0;
 192
 193         memcpy(&snap_key, &root->root_key, sizeof(snap_key));
 194         root->root_key.offset++;
 195
 196         btrfs_set_root_blocknr(&root->root_item, root->node->blocknr);
 197         ret = btrfs_insert_root(root->tree_root, &root->root_key,
 198                                 &root->root_item);
 199         BUG_ON(ret);
 200
 201         ret = commit_extent_and_tree_roots(root->tree_root, root->extent_root);
 202         BUG_ON(ret);
 203
 204         write_ctree_super(root, s);
 205         btrfs_finish_extent_commit(root->extent_root);
 206         btrfs_finish_extent_commit(root->tree_root);
 207
 208         root->commit_root = root->node;
 209         root->node->count++;
 210         ret = btrfs_drop_snapshot(root, snap);
 211         BUG_ON(ret);
 212
 213         ret = btrfs_del_root(root->tree_root, &snap_key);
 214         BUG_ON(ret);
 215
 216         return ret;
 217 }
 218
 219 static int __setup_root(struct btrfs_super_block *super,
 220                         struct btrfs_root *root, u64 objectid, int fp)
 221 {
 222         INIT_LIST_HEAD(&root->trans);
 223         INIT_LIST_HEAD(&root->cache);
 224         root->cache_size = 0;
 225         root->fp = fp;
 226         root->node = NULL;
 227         root->commit_root = NULL;
 228         root->blocksize = btrfs_super_blocksize(super);
 229         root->ref_cows = 0;
 230         memset(&root->current_insert, 0, sizeof(root->current_insert));
 231         memset(&root->last_insert, 0, sizeof(root->last_insert));
 232         memset(&root->root_key, 0, sizeof(root->root_key));
 233         memset(&root->root_item, 0, sizeof(root->root_item));
 234         return 0;
 235 }
 236
 237 static int find_and_setup_root(struct btrfs_super_block *super,
 238                                struct btrfs_root *tree_root, u64 objectid,
 239                                struct btrfs_root *root, int fp)
 240 {
 241         int ret;
 242
 243         __setup_root(super, root, objectid, fp);
 244         ret = btrfs_find_last_root(tree_root, objectid,
 245                                    &root->root_item, &root->root_key);
 246         BUG_ON(ret);
 247
 248         root->node = read_tree_block(root,
 249                                      btrfs_root_blocknr(&root->root_item));
 250         BUG_ON(!root->node);
 251         return 0;
 252 }
 253
 254 struct btrfs_root *open_ctree(char *filename, struct btrfs_super_block *super)
 255 {
 256         struct btrfs_root *root = malloc(sizeof(struct btrfs_root));
 257         struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
 258         struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
 259         int fp;
 260         int ret;
 261
 262         root->extent_root = extent_root;
 263         root->tree_root = tree_root;
 264
 265         extent_root->extent_root = extent_root;
 266         extent_root->tree_root = tree_root;
 267
 268         tree_root->extent_root = extent_root;
 269         tree_root->tree_root = tree_root;
 270
 271         fp = open(filename, O_CREAT | O_RDWR, 0600);
 272         if (fp < 0) {
 273                 free(root);
 274                 return NULL;
 275         }
 276         INIT_RADIX_TREE(&root->cache_radix, GFP_KERNEL);
 277         INIT_RADIX_TREE(&root->pinned_radix, GFP_KERNEL);
 278         INIT_RADIX_TREE(&extent_root->pinned_radix, GFP_KERNEL);
 279         INIT_RADIX_TREE(&extent_root->cache_radix, GFP_KERNEL);
 280         INIT_RADIX_TREE(&tree_root->pinned_radix, GFP_KERNEL);
 281         INIT_RADIX_TREE(&tree_root->cache_radix, GFP_KERNEL);
 282
 283         ret = pread(fp, super, sizeof(struct btrfs_super_block),
 284                      BTRFS_SUPER_INFO_OFFSET);
 285         if (ret == 0 || btrfs_super_root(super) == 0) {
 286                 printf("making new FS!\n");
 287                 ret = mkfs(fp, 0, 1024);
 288                 if (ret)
 289                         return NULL;
 290                 ret = pread(fp, super, sizeof(struct btrfs_super_block),
 291                              BTRFS_SUPER_INFO_OFFSET);
 292                 if (ret != sizeof(struct btrfs_super_block))
 293                         return NULL;
 294         }
 295         BUG_ON(ret < 0);
 296
 297         __setup_root(super, tree_root, BTRFS_ROOT_TREE_OBJECTID, fp);
 298         tree_root->node = read_tree_block(tree_root, btrfs_super_root(super));
 299         BUG_ON(!tree_root->node);
 300
 301         ret = find_and_setup_root(super, tree_root, BTRFS_EXTENT_TREE_OBJECTID,
 302                                   extent_root, fp);
 303         BUG_ON(ret);
 304
 305         ret = find_and_setup_root(super, tree_root, BTRFS_FS_TREE_OBJECTID,
 306                                   root, fp);
 307         BUG_ON(ret);
 308
 309         root->commit_root = root->node;
 310         root->node->count++;
 311         root->ref_cows = 1;
 312         return root;
 313 }
 314
 315 int write_ctree_super(struct btrfs_root *root, struct btrfs_super_block *s)
 316 {
 317         int ret;
 318         btrfs_set_super_root(s, root->tree_root->node->blocknr);
 319         ret = pwrite(root->fp, s, sizeof(*s),
 320                      BTRFS_SUPER_INFO_OFFSET);
 321         if (ret != sizeof(*s)) {
 322                 fprintf(stderr, "failed to write new super block err %d\n", ret);
 323                 return ret;
 324         }
 325         return 0;
 326 }
 327
 328 static int drop_cache(struct btrfs_root *root)
 329 {
 330         while(!list_empty(&root->cache)) {
 331                 struct btrfs_buffer *b = list_entry(root->cache.next,
 332                                                    struct btrfs_buffer, cache);
 333                 list_del_init(&b->cache);
 334                 btrfs_block_release(root, b);
 335         }
 336         return 0;
 337 }
 338 int close_ctree(struct btrfs_root *root, struct btrfs_super_block *s)
 339 {
 340         int ret;
 341         btrfs_commit_transaction(root, s);
 342         ret = commit_extent_and_tree_roots(root->tree_root, root->extent_root);
 343         BUG_ON(ret);
 344         write_ctree_super(root, s);
 345         drop_cache(root->extent_root);
 346         drop_cache(root->tree_root);
 347         drop_cache(root);
 348         BUG_ON(!list_empty(&root->trans));
 349         BUG_ON(!list_empty(&root->extent_root->trans));
 350         BUG_ON(!list_empty(&root->tree_root->trans));
 351
 352         close(root->fp);
 353         if (root->node)
 354                 btrfs_block_release(root, root->node);
 355         if (root->extent_root->node)
 356                 btrfs_block_release(root->extent_root, root->extent_root->node);
 357         if (root->tree_root->node)
 358                 btrfs_block_release(root->tree_root, root->tree_root->node);
 359         btrfs_block_release(root, root->commit_root);
 360         free(root);
 361         printf("on close %d blocks are allocated\n", allocated_blocks);
 362         return 0;
 363 }
 364
 365 void btrfs_block_release(struct btrfs_root *root, struct btrfs_buffer *buf)
 366 {
 367         buf->count--;
 368         if (buf->count < 0)
 369                 BUG();
 370         if (buf->count == 0) {
 371                 BUG_ON(!list_empty(&buf->cache));
 372                 BUG_ON(!list_empty(&buf->dirty));
 373                 if (!radix_tree_lookup(&root->cache_radix, buf->blocknr))
 374                         BUG();
 375                 radix_tree_delete(&root->cache_radix, buf->blocknr);
 376                 memset(buf, 0, sizeof(*buf));
 377                 free(buf);
 378                 BUG_ON(allocated_blocks == 0);
 379                 allocated_blocks--;
 380                 BUG_ON(root->cache_size == 0);
 381                 root->cache_size--;
 382         }
 383 }
 384