fs/btrfs/transaction.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/fs.h>
  20 #include <linux/sched.h>
  21 #include "ctree.h"
  22 #include "disk-io.h"
  23 #include "transaction.h"
  24
  25 static int total_trans = 0;
  26 extern struct kmem_cache *btrfs_trans_handle_cachep;
  27 extern struct kmem_cache *btrfs_transaction_cachep;
  28
  29 static struct workqueue_struct *trans_wq;
  30
  31 #define BTRFS_ROOT_TRANS_TAG 0
  32 #define BTRFS_ROOT_DEFRAG_TAG 1
  33
  34 static void put_transaction(struct btrfs_transaction *transaction)
  35 {
  36         WARN_ON(transaction->use_count == 0);
  37         transaction->use_count--;
  38         if (transaction->use_count == 0) {
  39                 WARN_ON(total_trans == 0);
  40                 total_trans--;
  41                 list_del_init(&transaction->list);
  42                 memset(transaction, 0, sizeof(*transaction));
  43                 kmem_cache_free(btrfs_transaction_cachep, transaction);
  44         }
  45 }
  46
  47 static int join_transaction(struct btrfs_root *root)
  48 {
  49         struct btrfs_transaction *cur_trans;
  50         cur_trans = root->fs_info->running_transaction;
  51         if (!cur_trans) {
  52                 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
  53                                              GFP_NOFS);
  54                 total_trans++;
  55                 BUG_ON(!cur_trans);
  56                 root->fs_info->generation++;
  57                 root->fs_info->running_transaction = cur_trans;
  58                 cur_trans->num_writers = 0;
  59                 cur_trans->transid = root->fs_info->generation;
  60                 init_waitqueue_head(&cur_trans->writer_wait);
  61                 init_waitqueue_head(&cur_trans->commit_wait);
  62                 cur_trans->in_commit = 0;
  63                 cur_trans->use_count = 1;
  64                 cur_trans->commit_done = 0;
  65                 cur_trans->start_time = get_seconds();
  66                 list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
  67                 init_bit_radix(&cur_trans->dirty_pages);
  68         }
  69         cur_trans->num_writers++;
  70         return 0;
  71 }
  72
  73 static int record_root_in_trans(struct btrfs_root *root)
  74 {
  75         u64 running_trans_id = root->fs_info->running_transaction->transid;
  76         if (root->ref_cows && root->last_trans < running_trans_id) {
  77                 WARN_ON(root == root->fs_info->extent_root);
  78                 if (root->root_item.refs != 0) {
  79                         radix_tree_tag_set(&root->fs_info->fs_roots_radix,
  80                                    (unsigned long)root->root_key.objectid,
  81                                    BTRFS_ROOT_TRANS_TAG);
  82                         radix_tree_tag_set(&root->fs_info->fs_roots_radix,
  83                                    (unsigned long)root->root_key.objectid,
  84                                    BTRFS_ROOT_DEFRAG_TAG);
  85                         root->commit_root = root->node;
  86                         get_bh(root->node);
  87                 } else {
  88                         WARN_ON(1);
  89                 }
  90                 root->last_trans = running_trans_id;
  91         }
  92         return 0;
  93 }
  94
  95 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
  96                                                    int num_blocks)
  97 {
  98         struct btrfs_trans_handle *h =
  99                 kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
 100         int ret;
 101
 102         mutex_lock(&root->fs_info->trans_mutex);
 103         ret = join_transaction(root);
 104         BUG_ON(ret);
 105
 106         record_root_in_trans(root);
 107         h->transid = root->fs_info->running_transaction->transid;
 108         h->transaction = root->fs_info->running_transaction;
 109         h->blocks_reserved = num_blocks;
 110         h->blocks_used = 0;
 111         h->block_group = NULL;
 112         h->alloc_exclude_nr = 0;
 113         h->alloc_exclude_start = 0;
 114         root->fs_info->running_transaction->use_count++;
 115         mutex_unlock(&root->fs_info->trans_mutex);
 116         return h;
 117 }
 118
 119 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
 120                           struct btrfs_root *root)
 121 {
 122         struct btrfs_transaction *cur_trans;
 123
 124         mutex_lock(&root->fs_info->trans_mutex);
 125         cur_trans = root->fs_info->running_transaction;
 126         WARN_ON(cur_trans != trans->transaction);
 127         WARN_ON(cur_trans->num_writers < 1);
 128         cur_trans->num_writers--;
 129         if (waitqueue_active(&cur_trans->writer_wait))
 130                 wake_up(&cur_trans->writer_wait);
 131         put_transaction(cur_trans);
 132         mutex_unlock(&root->fs_info->trans_mutex);
 133         memset(trans, 0, sizeof(*trans));
 134         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 135         return 0;
 136 }
 137
 138
 139 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
 140                                      struct btrfs_root *root)
 141 {
 142         unsigned long gang[16];
 143         int ret;
 144         int i;
 145         int err;
 146         int werr = 0;
 147         struct page *page;
 148         struct radix_tree_root *dirty_pages;
 149         struct inode *btree_inode = root->fs_info->btree_inode;
 150
 151         if (!trans || !trans->transaction) {
 152                 return filemap_write_and_wait(btree_inode->i_mapping);
 153         }
 154         dirty_pages = &trans->transaction->dirty_pages;
 155         while(1) {
 156                 ret = find_first_radix_bit(dirty_pages, gang,
 157                                            0, ARRAY_SIZE(gang));
 158                 if (!ret)
 159                         break;
 160                 for (i = 0; i < ret; i++) {
 161                         /* FIXME EIO */
 162                         clear_radix_bit(dirty_pages, gang[i]);
 163                         page = find_lock_page(btree_inode->i_mapping,
 164                                               gang[i]);
 165                         if (!page)
 166                                 continue;
 167                         if (PageWriteback(page)) {
 168                                 if (PageDirty(page))
 169                                         wait_on_page_writeback(page);
 170                                 else {
 171                                         unlock_page(page);
 172                                         page_cache_release(page);
 173                                         continue;
 174                                 }
 175                         }
 176                         err = write_one_page(page, 0);
 177                         if (err)
 178                                 werr = err;
 179                         page_cache_release(page);
 180                 }
 181         }
 182         err = filemap_fdatawait(btree_inode->i_mapping);
 183         if (err)
 184                 werr = err;
 185         return werr;
 186 }
 187
 188 int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
 189                             struct btrfs_root *root)
 190 {
 191         int ret;
 192         u64 old_extent_block;
 193         struct btrfs_fs_info *fs_info = root->fs_info;
 194         struct btrfs_root *tree_root = fs_info->tree_root;
 195         struct btrfs_root *extent_root = fs_info->extent_root;
 196
 197         btrfs_write_dirty_block_groups(trans, extent_root);
 198         while(1) {
 199                 old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
 200                 if (old_extent_block == bh_blocknr(extent_root->node))
 201                         break;
 202                 btrfs_set_root_blocknr(&extent_root->root_item,
 203                                        bh_blocknr(extent_root->node));
 204                 ret = btrfs_update_root(trans, tree_root,
 205                                         &extent_root->root_key,
 206                                         &extent_root->root_item);
 207                 BUG_ON(ret);
 208                 btrfs_write_dirty_block_groups(trans, extent_root);
 209         }
 210         return 0;
 211 }
 212
 213 static int wait_for_commit(struct btrfs_root *root,
 214                            struct btrfs_transaction *commit)
 215 {
 216         DEFINE_WAIT(wait);
 217         mutex_lock(&root->fs_info->trans_mutex);
 218         while(!commit->commit_done) {
 219                 prepare_to_wait(&commit->commit_wait, &wait,
 220                                 TASK_UNINTERRUPTIBLE);
 221                 if (commit->commit_done)
 222                         break;
 223                 mutex_unlock(&root->fs_info->trans_mutex);
 224                 schedule();
 225                 mutex_lock(&root->fs_info->trans_mutex);
 226         }
 227         mutex_unlock(&root->fs_info->trans_mutex);
 228         finish_wait(&commit->commit_wait, &wait);
 229         return 0;
 230 }
 231
 232 struct dirty_root {
 233         struct list_head list;
 234         struct btrfs_root *root;
 235 };
 236
 237 int btrfs_add_dead_root(struct btrfs_root *root, struct list_head *dead_list)
 238 {
 239         struct dirty_root *dirty;
 240
 241         dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
 242         if (!dirty)
 243                 return -ENOMEM;
 244         dirty->root = root;
 245         list_add(&dirty->list, dead_list);
 246         return 0;
 247 }
 248
 249 static int add_dirty_roots(struct btrfs_trans_handle *trans,
 250                            struct radix_tree_root *radix,
 251                            struct list_head *list)
 252 {
 253         struct dirty_root *dirty;
 254         struct btrfs_root *gang[8];
 255         struct btrfs_root *root;
 256         int i;
 257         int ret;
 258         int err = 0;
 259         u32 refs;
 260
 261         while(1) {
 262                 ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
 263                                                  ARRAY_SIZE(gang),
 264                                                  BTRFS_ROOT_TRANS_TAG);
 265                 if (ret == 0)
 266                         break;
 267                 for (i = 0; i < ret; i++) {
 268                         root = gang[i];
 269                         radix_tree_tag_clear(radix,
 270                                      (unsigned long)root->root_key.objectid,
 271                                      BTRFS_ROOT_TRANS_TAG);
 272                         if (root->commit_root == root->node) {
 273                                 WARN_ON(bh_blocknr(root->node) !=
 274                                         btrfs_root_blocknr(&root->root_item));
 275                                 brelse(root->commit_root);
 276                                 root->commit_root = NULL;
 277                                 continue;
 278                         }
 279                         dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
 280                         BUG_ON(!dirty);
 281                         dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS);
 282                         BUG_ON(!dirty->root);
 283
 284                         memset(&root->root_item.drop_progress, 0,
 285                                sizeof(struct btrfs_disk_key));
 286                         root->root_item.drop_level = 0;
 287
 288                         memcpy(dirty->root, root, sizeof(*root));
 289                         dirty->root->node = root->commit_root;
 290                         root->commit_root = NULL;
 291
 292                         root->root_key.offset = root->fs_info->generation;
 293                         btrfs_set_root_blocknr(&root->root_item,
 294                                                bh_blocknr(root->node));
 295                         err = btrfs_insert_root(trans, root->fs_info->tree_root,
 296                                                 &root->root_key,
 297                                                 &root->root_item);
 298                         if (err)
 299                                 break;
 300
 301                         refs = btrfs_root_refs(&dirty->root->root_item);
 302                         btrfs_set_root_refs(&dirty->root->root_item, refs - 1);
 303                         err = btrfs_update_root(trans, root->fs_info->tree_root,
 304                                                 &dirty->root->root_key,
 305                                                 &dirty->root->root_item);
 306
 307                         BUG_ON(err);
 308                         if (refs == 1) {
 309                                 list_add(&dirty->list, list);
 310                         } else {
 311                                 WARN_ON(1);
 312                                 kfree(dirty->root);
 313                                 kfree(dirty);
 314                         }
 315                 }
 316         }
 317         return err;
 318 }
 319
 320 int btrfs_defrag_dirty_roots(struct btrfs_fs_info *info)
 321 {
 322         struct btrfs_root *gang[1];
 323         struct btrfs_root *root;
 324         struct btrfs_root *tree_root = info->tree_root;
 325         struct btrfs_trans_handle *trans;
 326         int i;
 327         int ret;
 328         int err = 0;
 329         u64 last = 0;
 330
 331         trans = btrfs_start_transaction(tree_root, 1);
 332         while(1) {
 333                 ret = radix_tree_gang_lookup_tag(&info->fs_roots_radix,
 334                                                  (void **)gang, last,
 335                                                  ARRAY_SIZE(gang),
 336                                                  BTRFS_ROOT_DEFRAG_TAG);
 337                 if (ret == 0)
 338                         break;
 339                 for (i = 0; i < ret; i++) {
 340                         root = gang[i];
 341                         last = root->root_key.objectid + 1;
 342                         radix_tree_tag_clear(&info->fs_roots_radix,
 343                                      (unsigned long)root->root_key.objectid,
 344                                      BTRFS_ROOT_DEFRAG_TAG);
 345                         if (root->defrag_running)
 346                                 continue;
 347
 348                         while (1) {
 349                                 mutex_lock(&root->fs_info->trans_mutex);
 350                                 record_root_in_trans(root);
 351                                 mutex_unlock(&root->fs_info->trans_mutex);
 352
 353                                 root->defrag_running = 1;
 354                                 err = btrfs_defrag_leaves(trans, root, 1);
 355                                 btrfs_end_transaction(trans, tree_root);
 356                                 mutex_unlock(&info->fs_mutex);
 357
 358                                 btrfs_btree_balance_dirty(root);
 359                                 cond_resched();
 360
 361                                 mutex_lock(&info->fs_mutex);
 362                                 trans = btrfs_start_transaction(tree_root, 1);
 363                                 if (err != -EAGAIN)
 364                                         break;
 365                         }
 366                         root->defrag_running = 0;
 367                 }
 368         }
 369         btrfs_end_transaction(trans, tree_root);
 370         return err;
 371 }
 372
 373 static int drop_dirty_roots(struct btrfs_root *tree_root,
 374                             struct list_head *list)
 375 {
 376         struct dirty_root *dirty;
 377         struct btrfs_trans_handle *trans;
 378         int ret = 0;
 379         int err;
 380
 381         while(!list_empty(list)) {
 382                 mutex_lock(&tree_root->fs_info->fs_mutex);
 383                 dirty = list_entry(list->next, struct dirty_root, list);
 384                 list_del_init(&dirty->list);
 385
 386                 while(1) {
 387                         trans = btrfs_start_transaction(tree_root, 1);
 388                         ret = btrfs_drop_snapshot(trans, dirty->root);
 389                         if (ret != -EAGAIN) {
 390                                 break;
 391                         }
 392                         err = btrfs_update_root(trans,
 393                                         tree_root,
 394                                         &dirty->root->root_key,
 395                                         &dirty->root->root_item);
 396                         if (err)
 397                                 ret = err;
 398                         ret = btrfs_end_transaction(trans, tree_root);
 399                         BUG_ON(ret);
 400                         mutex_unlock(&tree_root->fs_info->fs_mutex);
 401
 402                         btrfs_btree_balance_dirty(tree_root);
 403                         schedule();
 404
 405                         mutex_lock(&tree_root->fs_info->fs_mutex);
 406                 }
 407                 BUG_ON(ret);
 408                 ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
 409                 if (ret)
 410                         break;
 411                 ret = btrfs_end_transaction(trans, tree_root);
 412                 BUG_ON(ret);
 413
 414                 kfree(dirty->root);
 415                 kfree(dirty);
 416                 mutex_unlock(&tree_root->fs_info->fs_mutex);
 417                 btrfs_btree_balance_dirty(tree_root);
 418                 schedule();
 419         }
 420         return ret;
 421 }
 422
 423 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 424                              struct btrfs_root *root)
 425 {
 426         int ret = 0;
 427         struct btrfs_transaction *cur_trans;
 428         struct btrfs_transaction *prev_trans = NULL;
 429         struct list_head dirty_fs_roots;
 430         struct radix_tree_root pinned_copy;
 431         DEFINE_WAIT(wait);
 432
 433         init_bit_radix(&pinned_copy);
 434         INIT_LIST_HEAD(&dirty_fs_roots);
 435
 436         mutex_lock(&root->fs_info->trans_mutex);
 437         if (trans->transaction->in_commit) {
 438                 cur_trans = trans->transaction;
 439                 trans->transaction->use_count++;
 440                 mutex_unlock(&root->fs_info->trans_mutex);
 441                 btrfs_end_transaction(trans, root);
 442
 443                 mutex_unlock(&root->fs_info->fs_mutex);
 444                 ret = wait_for_commit(root, cur_trans);
 445                 BUG_ON(ret);
 446                 put_transaction(cur_trans);
 447                 mutex_lock(&root->fs_info->fs_mutex);
 448                 return 0;
 449         }
 450         trans->transaction->in_commit = 1;
 451         cur_trans = trans->transaction;
 452         if (cur_trans->list.prev != &root->fs_info->trans_list) {
 453                 prev_trans = list_entry(cur_trans->list.prev,
 454                                         struct btrfs_transaction, list);
 455                 if (!prev_trans->commit_done) {
 456                         prev_trans->use_count++;
 457                         mutex_unlock(&root->fs_info->fs_mutex);
 458                         mutex_unlock(&root->fs_info->trans_mutex);
 459
 460                         wait_for_commit(root, prev_trans);
 461                         put_transaction(prev_trans);
 462
 463                         mutex_lock(&root->fs_info->fs_mutex);
 464                         mutex_lock(&root->fs_info->trans_mutex);
 465                 }
 466         }
 467         while (trans->transaction->num_writers > 1) {
 468                 WARN_ON(cur_trans != trans->transaction);
 469                 prepare_to_wait(&trans->transaction->writer_wait, &wait,
 470                                 TASK_UNINTERRUPTIBLE);
 471                 if (trans->transaction->num_writers <= 1)
 472                         break;
 473                 mutex_unlock(&root->fs_info->fs_mutex);
 474                 mutex_unlock(&root->fs_info->trans_mutex);
 475                 schedule();
 476                 mutex_lock(&root->fs_info->fs_mutex);
 477                 mutex_lock(&root->fs_info->trans_mutex);
 478                 finish_wait(&trans->transaction->writer_wait, &wait);
 479         }
 480         finish_wait(&trans->transaction->writer_wait, &wait);
 481         WARN_ON(cur_trans != trans->transaction);
 482         ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix,
 483                               &dirty_fs_roots);
 484         BUG_ON(ret);
 485
 486         ret = btrfs_commit_tree_roots(trans, root);
 487         BUG_ON(ret);
 488
 489         cur_trans = root->fs_info->running_transaction;
 490         root->fs_info->running_transaction = NULL;
 491         btrfs_set_super_generation(&root->fs_info->super_copy,
 492                                    cur_trans->transid);
 493         btrfs_set_super_root(&root->fs_info->super_copy,
 494                              bh_blocknr(root->fs_info->tree_root->node));
 495         memcpy(root->fs_info->disk_super, &root->fs_info->super_copy,
 496                sizeof(root->fs_info->super_copy));
 497
 498         btrfs_copy_pinned(root, &pinned_copy);
 499
 500         mutex_unlock(&root->fs_info->trans_mutex);
 501         mutex_unlock(&root->fs_info->fs_mutex);
 502         ret = btrfs_write_and_wait_transaction(trans, root);
 503         BUG_ON(ret);
 504         write_ctree_super(trans, root);
 505         mutex_lock(&root->fs_info->fs_mutex);
 506         btrfs_finish_extent_commit(trans, root, &pinned_copy);
 507         mutex_lock(&root->fs_info->trans_mutex);
 508         cur_trans->commit_done = 1;
 509         wake_up(&cur_trans->commit_wait);
 510         put_transaction(cur_trans);
 511         put_transaction(cur_trans);
 512         if (root->fs_info->closing)
 513                 list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
 514         else
 515                 list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
 516         mutex_unlock(&root->fs_info->trans_mutex);
 517         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 518
 519         if (root->fs_info->closing) {
 520                 mutex_unlock(&root->fs_info->fs_mutex);
 521                 drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
 522                 mutex_lock(&root->fs_info->fs_mutex);
 523         }
 524         return ret;
 525 }
 526
 527 void btrfs_transaction_cleaner(struct work_struct *work)
 528 {
 529         struct btrfs_fs_info *fs_info = container_of(work,
 530                                                      struct btrfs_fs_info,
 531                                                      trans_work.work);
 532
 533         struct btrfs_root *root = fs_info->tree_root;
 534         struct btrfs_transaction *cur;
 535         struct btrfs_trans_handle *trans;
 536         struct list_head dirty_roots;
 537         unsigned long now;
 538         unsigned long delay = HZ * 30;
 539         int ret;
 540
 541         INIT_LIST_HEAD(&dirty_roots);
 542         mutex_lock(&root->fs_info->fs_mutex);
 543         mutex_lock(&root->fs_info->trans_mutex);
 544         cur = root->fs_info->running_transaction;
 545         if (!cur) {
 546                 mutex_unlock(&root->fs_info->trans_mutex);
 547                 goto out;
 548         }
 549         now = get_seconds();
 550         if (now < cur->start_time || now - cur->start_time < 30) {
 551                 mutex_unlock(&root->fs_info->trans_mutex);
 552                 delay = HZ * 5;
 553                 goto out;
 554         }
 555         mutex_unlock(&root->fs_info->trans_mutex);
 556         btrfs_defrag_dirty_roots(root->fs_info);
 557         trans = btrfs_start_transaction(root, 1);
 558         ret = btrfs_commit_transaction(trans, root);
 559 out:
 560         mutex_unlock(&root->fs_info->fs_mutex);
 561
 562         mutex_lock(&root->fs_info->trans_mutex);
 563         list_splice_init(&root->fs_info->dead_roots, &dirty_roots);
 564         mutex_unlock(&root->fs_info->trans_mutex);
 565
 566         if (!list_empty(&dirty_roots)) {
 567                 drop_dirty_roots(root, &dirty_roots);
 568         }
 569         btrfs_transaction_queue_work(root, delay);
 570 }
 571
 572 void btrfs_transaction_queue_work(struct btrfs_root *root, int delay)
 573 {
 574         queue_delayed_work(trans_wq, &root->fs_info->trans_work, delay);
 575 }
 576
 577 void btrfs_transaction_flush_work(struct btrfs_root *root)
 578 {
 579         cancel_rearming_delayed_workqueue(trans_wq, &root->fs_info->trans_work);
 580         flush_workqueue(trans_wq);
 581 }
 582
 583 void __init btrfs_init_transaction_sys(void)
 584 {
 585         trans_wq = create_workqueue("btrfs");
 586 }
 587
 588 void __exit btrfs_exit_transaction_sys(void)
 589 {
 590         destroy_workqueue(trans_wq);
 591 }
 592