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                         radix_tree_tag_clear(&info->fs_roots_radix,
 368                                      (unsigned long)root->root_key.objectid,
 369                                      BTRFS_ROOT_DEFRAG_TAG);
 370                 }
 371         }
 372         btrfs_end_transaction(trans, tree_root);
 373         return err;
 374 }
 375
 376 static int drop_dirty_roots(struct btrfs_root *tree_root,
 377                             struct list_head *list)
 378 {
 379         struct dirty_root *dirty;
 380         struct btrfs_trans_handle *trans;
 381         int ret = 0;
 382         int err;
 383
 384         while(!list_empty(list)) {
 385                 mutex_lock(&tree_root->fs_info->fs_mutex);
 386                 dirty = list_entry(list->next, struct dirty_root, list);
 387                 list_del_init(&dirty->list);
 388
 389                 while(1) {
 390                         trans = btrfs_start_transaction(tree_root, 1);
 391                         ret = btrfs_drop_snapshot(trans, dirty->root);
 392                         if (ret != -EAGAIN) {
 393                                 break;
 394                         }
 395                         err = btrfs_update_root(trans,
 396                                         tree_root,
 397                                         &dirty->root->root_key,
 398                                         &dirty->root->root_item);
 399                         if (err)
 400                                 ret = err;
 401                         ret = btrfs_end_transaction(trans, tree_root);
 402                         BUG_ON(ret);
 403                         mutex_unlock(&tree_root->fs_info->fs_mutex);
 404
 405                         btrfs_btree_balance_dirty(tree_root);
 406                         schedule();
 407
 408                         mutex_lock(&tree_root->fs_info->fs_mutex);
 409                 }
 410                 BUG_ON(ret);
 411                 ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
 412                 if (ret)
 413                         break;
 414                 ret = btrfs_end_transaction(trans, tree_root);
 415                 BUG_ON(ret);
 416
 417                 kfree(dirty->root);
 418                 kfree(dirty);
 419                 mutex_unlock(&tree_root->fs_info->fs_mutex);
 420                 btrfs_btree_balance_dirty(tree_root);
 421                 schedule();
 422         }
 423         return ret;
 424 }
 425
 426 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 427                              struct btrfs_root *root)
 428 {
 429         int ret = 0;
 430         struct btrfs_transaction *cur_trans;
 431         struct btrfs_transaction *prev_trans = NULL;
 432         struct list_head dirty_fs_roots;
 433         struct radix_tree_root pinned_copy;
 434         DEFINE_WAIT(wait);
 435
 436         init_bit_radix(&pinned_copy);
 437         INIT_LIST_HEAD(&dirty_fs_roots);
 438
 439         mutex_lock(&root->fs_info->trans_mutex);
 440         if (trans->transaction->in_commit) {
 441                 cur_trans = trans->transaction;
 442                 trans->transaction->use_count++;
 443                 mutex_unlock(&root->fs_info->trans_mutex);
 444                 btrfs_end_transaction(trans, root);
 445
 446                 mutex_unlock(&root->fs_info->fs_mutex);
 447                 ret = wait_for_commit(root, cur_trans);
 448                 BUG_ON(ret);
 449                 put_transaction(cur_trans);
 450                 mutex_lock(&root->fs_info->fs_mutex);
 451                 return 0;
 452         }
 453         trans->transaction->in_commit = 1;
 454         cur_trans = trans->transaction;
 455         if (cur_trans->list.prev != &root->fs_info->trans_list) {
 456                 prev_trans = list_entry(cur_trans->list.prev,
 457                                         struct btrfs_transaction, list);
 458                 if (!prev_trans->commit_done) {
 459                         prev_trans->use_count++;
 460                         mutex_unlock(&root->fs_info->fs_mutex);
 461                         mutex_unlock(&root->fs_info->trans_mutex);
 462
 463                         wait_for_commit(root, prev_trans);
 464                         put_transaction(prev_trans);
 465
 466                         mutex_lock(&root->fs_info->fs_mutex);
 467                         mutex_lock(&root->fs_info->trans_mutex);
 468                 }
 469         }
 470         while (trans->transaction->num_writers > 1) {
 471                 WARN_ON(cur_trans != trans->transaction);
 472                 prepare_to_wait(&trans->transaction->writer_wait, &wait,
 473                                 TASK_UNINTERRUPTIBLE);
 474                 if (trans->transaction->num_writers <= 1)
 475                         break;
 476                 mutex_unlock(&root->fs_info->fs_mutex);
 477                 mutex_unlock(&root->fs_info->trans_mutex);
 478                 schedule();
 479                 mutex_lock(&root->fs_info->fs_mutex);
 480                 mutex_lock(&root->fs_info->trans_mutex);
 481                 finish_wait(&trans->transaction->writer_wait, &wait);
 482         }
 483         finish_wait(&trans->transaction->writer_wait, &wait);
 484         WARN_ON(cur_trans != trans->transaction);
 485         ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix,
 486                               &dirty_fs_roots);
 487         BUG_ON(ret);
 488
 489         ret = btrfs_commit_tree_roots(trans, root);
 490         BUG_ON(ret);
 491
 492         cur_trans = root->fs_info->running_transaction;
 493         root->fs_info->running_transaction = NULL;
 494         btrfs_set_super_generation(&root->fs_info->super_copy,
 495                                    cur_trans->transid);
 496         btrfs_set_super_root(&root->fs_info->super_copy,
 497                              bh_blocknr(root->fs_info->tree_root->node));
 498         memcpy(root->fs_info->disk_super, &root->fs_info->super_copy,
 499                sizeof(root->fs_info->super_copy));
 500
 501         btrfs_copy_pinned(root, &pinned_copy);
 502
 503         mutex_unlock(&root->fs_info->trans_mutex);
 504         mutex_unlock(&root->fs_info->fs_mutex);
 505         ret = btrfs_write_and_wait_transaction(trans, root);
 506         BUG_ON(ret);
 507         write_ctree_super(trans, root);
 508         mutex_lock(&root->fs_info->fs_mutex);
 509         btrfs_finish_extent_commit(trans, root, &pinned_copy);
 510         mutex_lock(&root->fs_info->trans_mutex);
 511         cur_trans->commit_done = 1;
 512         wake_up(&cur_trans->commit_wait);
 513         put_transaction(cur_trans);
 514         put_transaction(cur_trans);
 515         if (root->fs_info->closing)
 516                 list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
 517         else
 518                 list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
 519         mutex_unlock(&root->fs_info->trans_mutex);
 520         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 521
 522         if (root->fs_info->closing) {
 523                 mutex_unlock(&root->fs_info->fs_mutex);
 524                 drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
 525                 mutex_lock(&root->fs_info->fs_mutex);
 526         }
 527         return ret;
 528 }
 529
 530 void btrfs_transaction_cleaner(struct work_struct *work)
 531 {
 532         struct btrfs_fs_info *fs_info = container_of(work,
 533                                                      struct btrfs_fs_info,
 534                                                      trans_work.work);
 535
 536         struct btrfs_root *root = fs_info->tree_root;
 537         struct btrfs_transaction *cur;
 538         struct btrfs_trans_handle *trans;
 539         struct list_head dirty_roots;
 540         unsigned long now;
 541         unsigned long delay = HZ * 30;
 542         int ret;
 543
 544         INIT_LIST_HEAD(&dirty_roots);
 545         mutex_lock(&root->fs_info->fs_mutex);
 546         mutex_lock(&root->fs_info->trans_mutex);
 547         cur = root->fs_info->running_transaction;
 548         if (!cur) {
 549                 mutex_unlock(&root->fs_info->trans_mutex);
 550                 goto out;
 551         }
 552         now = get_seconds();
 553         if (now < cur->start_time || now - cur->start_time < 30) {
 554                 mutex_unlock(&root->fs_info->trans_mutex);
 555                 delay = HZ * 5;
 556                 goto out;
 557         }
 558         mutex_unlock(&root->fs_info->trans_mutex);
 559         btrfs_defrag_dirty_roots(root->fs_info);
 560         trans = btrfs_start_transaction(root, 1);
 561         ret = btrfs_commit_transaction(trans, root);
 562 out:
 563         mutex_unlock(&root->fs_info->fs_mutex);
 564
 565         mutex_lock(&root->fs_info->trans_mutex);
 566         list_splice_init(&root->fs_info->dead_roots, &dirty_roots);
 567         mutex_unlock(&root->fs_info->trans_mutex);
 568
 569         if (!list_empty(&dirty_roots)) {
 570                 drop_dirty_roots(root, &dirty_roots);
 571         }
 572         btrfs_transaction_queue_work(root, delay);
 573 }
 574
 575 void btrfs_transaction_queue_work(struct btrfs_root *root, int delay)
 576 {
 577         queue_delayed_work(trans_wq, &root->fs_info->trans_work, delay);
 578 }
 579
 580 void btrfs_transaction_flush_work(struct btrfs_root *root)
 581 {
 582         cancel_rearming_delayed_workqueue(trans_wq, &root->fs_info->trans_work);
 583         flush_workqueue(trans_wq);
 584 }
 585
 586 void __init btrfs_init_transaction_sys(void)
 587 {
 588         trans_wq = create_workqueue("btrfs");
 589 }
 590
 591 void __exit btrfs_exit_transaction_sys(void)
 592 {
 593         destroy_workqueue(trans_wq);
 594 }
 595