fs/btrfs/transaction.c

   1 #include <linux/module.h>
   2 #include <linux/fs.h>
   3 #include "ctree.h"
   4 #include "disk-io.h"
   5 #include "transaction.h"
   6
   7 static int total_trans = 0;
   8 extern struct kmem_cache *btrfs_trans_handle_cachep;
   9 extern struct kmem_cache *btrfs_transaction_cachep;
  10
  11 static struct workqueue_struct *trans_wq;
  12
  13 #define BTRFS_ROOT_TRANS_TAG 0
  14
  15 #define TRANS_MAGIC 0xE1E10E
  16 static void put_transaction(struct btrfs_transaction *transaction)
  17 {
  18         WARN_ON(transaction->use_count == 0);
  19         transaction->use_count--;
  20         WARN_ON(transaction->magic != TRANS_MAGIC);
  21         if (transaction->use_count == 0) {
  22                 WARN_ON(total_trans == 0);
  23                 total_trans--;
  24                 list_del_init(&transaction->list);
  25                 memset(transaction, 0, sizeof(*transaction));
  26                 kmem_cache_free(btrfs_transaction_cachep, transaction);
  27         }
  28 }
  29
  30 static int join_transaction(struct btrfs_root *root)
  31 {
  32         struct btrfs_transaction *cur_trans;
  33         cur_trans = root->fs_info->running_transaction;
  34         if (!cur_trans) {
  35                 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
  36                                              GFP_NOFS);
  37                 total_trans++;
  38                 BUG_ON(!cur_trans);
  39                 root->fs_info->generation++;
  40                 root->fs_info->running_transaction = cur_trans;
  41                 cur_trans->num_writers = 0;
  42                 cur_trans->transid = root->fs_info->generation;
  43                 init_waitqueue_head(&cur_trans->writer_wait);
  44                 init_waitqueue_head(&cur_trans->commit_wait);
  45                 cur_trans->magic = TRANS_MAGIC;
  46                 cur_trans->in_commit = 0;
  47                 cur_trans->use_count = 1;
  48                 cur_trans->commit_done = 0;
  49                 cur_trans->start_time = get_seconds();
  50                 list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
  51                 init_bit_radix(&cur_trans->dirty_pages);
  52         }
  53         cur_trans->num_writers++;
  54         return 0;
  55 }
  56
  57 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
  58                                                    int num_blocks)
  59 {
  60         struct btrfs_trans_handle *h =
  61                 kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
  62         int ret;
  63         u64 running_trans_id;
  64
  65         mutex_lock(&root->fs_info->trans_mutex);
  66         ret = join_transaction(root);
  67         BUG_ON(ret);
  68         running_trans_id = root->fs_info->running_transaction->transid;
  69
  70         if (root != root->fs_info->tree_root && root->last_trans <
  71             running_trans_id) {
  72                 radix_tree_tag_set(&root->fs_info->fs_roots_radix,
  73                                    (unsigned long)root->root_key.objectid,
  74                                    BTRFS_ROOT_TRANS_TAG);
  75                 root->commit_root = root->node;
  76                 get_bh(root->node);
  77         }
  78         root->last_trans = running_trans_id;
  79         h->transid = running_trans_id;
  80         h->transaction = root->fs_info->running_transaction;
  81         h->blocks_reserved = num_blocks;
  82         h->blocks_used = 0;
  83         h->block_group = NULL;
  84         root->fs_info->running_transaction->use_count++;
  85         mutex_unlock(&root->fs_info->trans_mutex);
  86         h->magic = h->magic2 = TRANS_MAGIC;
  87         return h;
  88 }
  89
  90 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
  91                           struct btrfs_root *root)
  92 {
  93         struct btrfs_transaction *cur_trans;
  94
  95         WARN_ON(trans->magic != TRANS_MAGIC);
  96         WARN_ON(trans->magic2 != TRANS_MAGIC);
  97         mutex_lock(&root->fs_info->trans_mutex);
  98         cur_trans = root->fs_info->running_transaction;
  99         WARN_ON(cur_trans->num_writers < 1);
 100         if (waitqueue_active(&cur_trans->writer_wait))
 101                 wake_up(&cur_trans->writer_wait);
 102         cur_trans->num_writers--;
 103         put_transaction(cur_trans);
 104         mutex_unlock(&root->fs_info->trans_mutex);
 105         memset(trans, 0, sizeof(*trans));
 106         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 107         return 0;
 108 }
 109
 110
 111 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
 112                                      struct btrfs_root *root)
 113 {
 114         unsigned long gang[16];
 115         int ret;
 116         int i;
 117         int err;
 118         int werr = 0;
 119         struct page *page;
 120         struct radix_tree_root *dirty_pages;
 121         struct inode *btree_inode = root->fs_info->btree_inode;
 122
 123         if (!trans || !trans->transaction) {
 124                 return filemap_write_and_wait(btree_inode->i_mapping);
 125         }
 126         dirty_pages = &trans->transaction->dirty_pages;
 127         while(1) {
 128                 ret = find_first_radix_bit(dirty_pages, gang,
 129                                            0, ARRAY_SIZE(gang));
 130                 if (!ret)
 131                         break;
 132                 for (i = 0; i < ret; i++) {
 133                         /* FIXME EIO */
 134                         clear_radix_bit(dirty_pages, gang[i]);
 135                         page = find_lock_page(btree_inode->i_mapping,
 136                                               gang[i]);
 137                         if (!page)
 138                                 continue;
 139                         err = write_one_page(page, 0);
 140                         if (err)
 141                                 werr = err;
 142                         page_cache_release(page);
 143                 }
 144         }
 145         err = filemap_fdatawait(btree_inode->i_mapping);
 146         if (err)
 147                 werr = err;
 148         return werr;
 149 }
 150
 151 int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
 152                             struct btrfs_root *root)
 153 {
 154         int ret;
 155         u64 old_extent_block;
 156         struct btrfs_fs_info *fs_info = root->fs_info;
 157         struct btrfs_root *tree_root = fs_info->tree_root;
 158         struct btrfs_root *extent_root = fs_info->extent_root;
 159         struct btrfs_root *dev_root = fs_info->dev_root;
 160
 161         if (btrfs_super_device_root(fs_info->disk_super) !=
 162             bh_blocknr(dev_root->node)) {
 163                 btrfs_set_super_device_root(fs_info->disk_super,
 164                                             bh_blocknr(dev_root->node));
 165         }
 166         btrfs_write_dirty_block_groups(trans, extent_root);
 167         while(1) {
 168                 old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
 169                 if (old_extent_block == bh_blocknr(extent_root->node))
 170                         break;
 171                 btrfs_set_root_blocknr(&extent_root->root_item,
 172                                        bh_blocknr(extent_root->node));
 173                 ret = btrfs_update_root(trans, tree_root,
 174                                         &extent_root->root_key,
 175                                         &extent_root->root_item);
 176                 BUG_ON(ret);
 177                 btrfs_write_dirty_block_groups(trans, extent_root);
 178         }
 179         return 0;
 180 }
 181
 182 static int wait_for_commit(struct btrfs_root *root,
 183                            struct btrfs_transaction *commit)
 184 {
 185         DEFINE_WAIT(wait);
 186         while(!commit->commit_done) {
 187                 prepare_to_wait(&commit->commit_wait, &wait,
 188                                 TASK_UNINTERRUPTIBLE);
 189                 if (commit->commit_done)
 190                         break;
 191                 mutex_unlock(&root->fs_info->trans_mutex);
 192                 schedule();
 193                 mutex_lock(&root->fs_info->trans_mutex);
 194         }
 195         finish_wait(&commit->commit_wait, &wait);
 196         return 0;
 197 }
 198
 199 struct dirty_root {
 200         struct list_head list;
 201         struct btrfs_key snap_key;
 202         struct buffer_head *commit_root;
 203         struct btrfs_root *root;
 204 };
 205
 206 static int add_dirty_roots(struct btrfs_trans_handle *trans,
 207                            struct radix_tree_root *radix,
 208                            struct list_head *list)
 209 {
 210         struct dirty_root *dirty;
 211         struct btrfs_root *gang[8];
 212         struct btrfs_root *root;
 213         int i;
 214         int ret;
 215         int err;
 216         while(1) {
 217                 ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
 218                                                  ARRAY_SIZE(gang),
 219                                                  BTRFS_ROOT_TRANS_TAG);
 220                 if (ret == 0)
 221                         break;
 222                 for (i = 0; i < ret; i++) {
 223                         root = gang[i];
 224                         radix_tree_tag_clear(radix,
 225                                      (unsigned long)root->root_key.objectid,
 226                                      BTRFS_ROOT_TRANS_TAG);
 227                         if (root->commit_root == root->node) {
 228                                 WARN_ON(bh_blocknr(root->node) !=
 229                                         btrfs_root_blocknr(&root->root_item));
 230                                 brelse(root->commit_root);
 231                                 root->commit_root = NULL;
 232                                 continue;
 233                         }
 234                         dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
 235                         BUG_ON(!dirty);
 236                         memcpy(&dirty->snap_key, &root->root_key,
 237                                sizeof(root->root_key));
 238                         dirty->commit_root = root->commit_root;
 239                         root->commit_root = NULL;
 240                         dirty->root = root;
 241                         root->root_key.offset = root->fs_info->generation;
 242                         btrfs_set_root_blocknr(&root->root_item,
 243                                                bh_blocknr(root->node));
 244                         err = btrfs_insert_root(trans, root->fs_info->tree_root,
 245                                                 &root->root_key,
 246                                                 &root->root_item);
 247                         BUG_ON(err);
 248                         list_add(&dirty->list, list);
 249                 }
 250         }
 251         return 0;
 252 }
 253
 254 static int drop_dirty_roots(struct btrfs_root *tree_root,
 255                             struct list_head *list)
 256 {
 257         struct dirty_root *dirty;
 258         struct btrfs_trans_handle *trans;
 259         int ret;
 260
 261         while(!list_empty(list)) {
 262                 dirty = list_entry(list->next, struct dirty_root, list);
 263                 list_del_init(&dirty->list);
 264                 trans = btrfs_start_transaction(tree_root, 1);
 265                 ret = btrfs_drop_snapshot(trans, dirty->root,
 266                                           dirty->commit_root);
 267                 BUG_ON(ret);
 268
 269                 ret = btrfs_del_root(trans, tree_root, &dirty->snap_key);
 270                 BUG_ON(ret);
 271                 ret = btrfs_end_transaction(trans, tree_root);
 272                 BUG_ON(ret);
 273                 kfree(dirty);
 274         }
 275         return 0;
 276 }
 277
 278 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 279                              struct btrfs_root *root)
 280 {
 281         int ret = 0;
 282         struct btrfs_transaction *cur_trans;
 283         struct btrfs_transaction *prev_trans = NULL;
 284         struct list_head dirty_fs_roots;
 285         DEFINE_WAIT(wait);
 286
 287         INIT_LIST_HEAD(&dirty_fs_roots);
 288
 289         mutex_lock(&root->fs_info->trans_mutex);
 290         if (trans->transaction->in_commit) {
 291                 cur_trans = trans->transaction;
 292                 trans->transaction->use_count++;
 293                 btrfs_end_transaction(trans, root);
 294                 ret = wait_for_commit(root, cur_trans);
 295                 BUG_ON(ret);
 296                 put_transaction(cur_trans);
 297                 mutex_unlock(&root->fs_info->trans_mutex);
 298                 return 0;
 299         }
 300         cur_trans = trans->transaction;
 301         trans->transaction->in_commit = 1;
 302         while (trans->transaction->num_writers > 1) {
 303                 WARN_ON(cur_trans != trans->transaction);
 304                 prepare_to_wait(&trans->transaction->writer_wait, &wait,
 305                                 TASK_UNINTERRUPTIBLE);
 306                 if (trans->transaction->num_writers <= 1)
 307                         break;
 308                 mutex_unlock(&root->fs_info->trans_mutex);
 309                 schedule();
 310                 mutex_lock(&root->fs_info->trans_mutex);
 311                 finish_wait(&trans->transaction->writer_wait, &wait);
 312         }
 313         finish_wait(&trans->transaction->writer_wait, &wait);
 314         WARN_ON(cur_trans != trans->transaction);
 315         add_dirty_roots(trans, &root->fs_info->fs_roots_radix, &dirty_fs_roots);
 316         ret = btrfs_commit_tree_roots(trans, root);
 317         BUG_ON(ret);
 318         cur_trans = root->fs_info->running_transaction;
 319         root->fs_info->running_transaction = NULL;
 320         if (cur_trans->list.prev != &root->fs_info->trans_list) {
 321                 prev_trans = list_entry(cur_trans->list.prev,
 322                                         struct btrfs_transaction, list);
 323                 if (prev_trans->commit_done)
 324                         prev_trans = NULL;
 325                 else
 326                         prev_trans->use_count++;
 327         }
 328         mutex_unlock(&root->fs_info->trans_mutex);
 329         mutex_unlock(&root->fs_info->fs_mutex);
 330         ret = btrfs_write_and_wait_transaction(trans, root);
 331         if (prev_trans) {
 332                 mutex_lock(&root->fs_info->trans_mutex);
 333                 wait_for_commit(root, prev_trans);
 334                 put_transaction(prev_trans);
 335                 mutex_unlock(&root->fs_info->trans_mutex);
 336         }
 337         btrfs_set_super_generation(root->fs_info->disk_super,
 338                                    cur_trans->transid);
 339         BUG_ON(ret);
 340         write_ctree_super(trans, root);
 341
 342         mutex_lock(&root->fs_info->fs_mutex);
 343         btrfs_finish_extent_commit(trans, root);
 344         mutex_lock(&root->fs_info->trans_mutex);
 345         cur_trans->commit_done = 1;
 346         wake_up(&cur_trans->commit_wait);
 347         put_transaction(cur_trans);
 348         put_transaction(cur_trans);
 349         mutex_unlock(&root->fs_info->trans_mutex);
 350         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 351
 352         drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
 353         return ret;
 354 }
 355
 356 void btrfs_transaction_cleaner(struct work_struct *work)
 357 {
 358         struct btrfs_fs_info *fs_info = container_of(work,
 359                                                      struct btrfs_fs_info,
 360                                                      trans_work.work);
 361
 362         struct btrfs_root *root = fs_info->tree_root;
 363         struct btrfs_transaction *cur;
 364         struct btrfs_trans_handle *trans;
 365         unsigned long now;
 366         unsigned long delay = HZ * 30;
 367         int ret;
 368
 369 printk("btrfs transaction cleaner\n");
 370         mutex_lock(&root->fs_info->fs_mutex);
 371         mutex_lock(&root->fs_info->trans_mutex);
 372         cur = root->fs_info->running_transaction;
 373         if (!cur) {
 374                 mutex_unlock(&root->fs_info->trans_mutex);
 375                 goto out;
 376         }
 377         now = get_seconds();
 378         if (now < cur->start_time || now - cur->start_time < 30) {
 379                 mutex_unlock(&root->fs_info->trans_mutex);
 380                 delay = HZ * 5;
 381                 goto out;
 382         }
 383         mutex_unlock(&root->fs_info->trans_mutex);
 384 printk("forcing commit\n");
 385         trans = btrfs_start_transaction(root, 1);
 386         ret = btrfs_commit_transaction(trans, root);
 387 out:
 388         mutex_unlock(&root->fs_info->fs_mutex);
 389         btrfs_transaction_queue_work(root, delay);
 390 }
 391
 392 void btrfs_transaction_queue_work(struct btrfs_root *root, int delay)
 393 {
 394         queue_delayed_work(trans_wq, &root->fs_info->trans_work, delay);
 395 }
 396
 397 void btrfs_transaction_flush_work(struct btrfs_root *root)
 398 {
 399         cancel_rearming_delayed_workqueue(trans_wq, &root->fs_info->trans_work);
 400         flush_workqueue(trans_wq);
 401 }
 402
 403 void __init btrfs_init_transaction_sys(void)
 404 {
 405         trans_wq = create_workqueue("btrfs");
 406 }
 407
 408 void __exit btrfs_exit_transaction_sys(void)
 409 {
 410         destroy_workqueue(trans_wq);
 411 }
 412