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
  33 static void put_transaction(struct btrfs_transaction *transaction)
  34 {
  35         WARN_ON(transaction->use_count == 0);
  36         transaction->use_count--;
  37         if (transaction->use_count == 0) {
  38                 WARN_ON(total_trans == 0);
  39                 total_trans--;
  40                 list_del_init(&transaction->list);
  41                 memset(transaction, 0, sizeof(*transaction));
  42                 kmem_cache_free(btrfs_transaction_cachep, transaction);
  43         }
  44 }
  45
  46 static int join_transaction(struct btrfs_root *root)
  47 {
  48         struct btrfs_transaction *cur_trans;
  49         cur_trans = root->fs_info->running_transaction;
  50         if (!cur_trans) {
  51                 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
  52                                              GFP_NOFS);
  53                 total_trans++;
  54                 BUG_ON(!cur_trans);
  55                 root->fs_info->generation++;
  56                 root->fs_info->running_transaction = cur_trans;
  57                 cur_trans->num_writers = 0;
  58                 cur_trans->transid = root->fs_info->generation;
  59                 init_waitqueue_head(&cur_trans->writer_wait);
  60                 init_waitqueue_head(&cur_trans->commit_wait);
  61                 cur_trans->in_commit = 0;
  62                 cur_trans->use_count = 1;
  63                 cur_trans->commit_done = 0;
  64                 cur_trans->start_time = get_seconds();
  65                 list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
  66                 init_bit_radix(&cur_trans->dirty_pages);
  67         }
  68         cur_trans->num_writers++;
  69         return 0;
  70 }
  71
  72 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
  73                                                    int num_blocks)
  74 {
  75         struct btrfs_trans_handle *h =
  76                 kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
  77         int ret;
  78         u64 running_trans_id;
  79
  80         mutex_lock(&root->fs_info->trans_mutex);
  81         ret = join_transaction(root);
  82         BUG_ON(ret);
  83         running_trans_id = root->fs_info->running_transaction->transid;
  84
  85         if (root != root->fs_info->tree_root && root->last_trans <
  86             running_trans_id) {
  87                 WARN_ON(root == root->fs_info->extent_root);
  88                 WARN_ON(root->ref_cows != 1);
  89                 if (root->root_item.refs != 0) {
  90                         radix_tree_tag_set(&root->fs_info->fs_roots_radix,
  91                                            (unsigned long)root->root_key.objectid,
  92                                            BTRFS_ROOT_TRANS_TAG);
  93                         root->commit_root = root->node;
  94                         get_bh(root->node);
  95                 } else {
  96                         WARN_ON(1);
  97                 }
  98         }
  99         root->last_trans = running_trans_id;
 100         h->transid = running_trans_id;
 101         h->transaction = root->fs_info->running_transaction;
 102         h->blocks_reserved = num_blocks;
 103         h->blocks_used = 0;
 104         h->block_group = NULL;
 105         root->fs_info->running_transaction->use_count++;
 106         mutex_unlock(&root->fs_info->trans_mutex);
 107         return h;
 108 }
 109
 110 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
 111                           struct btrfs_root *root)
 112 {
 113         struct btrfs_transaction *cur_trans;
 114
 115         mutex_lock(&root->fs_info->trans_mutex);
 116         cur_trans = root->fs_info->running_transaction;
 117         WARN_ON(cur_trans != trans->transaction);
 118         WARN_ON(cur_trans->num_writers < 1);
 119         cur_trans->num_writers--;
 120         if (waitqueue_active(&cur_trans->writer_wait))
 121                 wake_up(&cur_trans->writer_wait);
 122         put_transaction(cur_trans);
 123         mutex_unlock(&root->fs_info->trans_mutex);
 124         memset(trans, 0, sizeof(*trans));
 125         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 126         return 0;
 127 }
 128
 129
 130 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
 131                                      struct btrfs_root *root)
 132 {
 133         unsigned long gang[16];
 134         int ret;
 135         int i;
 136         int err;
 137         int werr = 0;
 138         struct page *page;
 139         struct radix_tree_root *dirty_pages;
 140         struct inode *btree_inode = root->fs_info->btree_inode;
 141
 142         if (!trans || !trans->transaction) {
 143                 return filemap_write_and_wait(btree_inode->i_mapping);
 144         }
 145         dirty_pages = &trans->transaction->dirty_pages;
 146         while(1) {
 147                 ret = find_first_radix_bit(dirty_pages, gang,
 148                                            0, ARRAY_SIZE(gang));
 149                 if (!ret)
 150                         break;
 151                 for (i = 0; i < ret; i++) {
 152                         /* FIXME EIO */
 153                         clear_radix_bit(dirty_pages, gang[i]);
 154                         page = find_lock_page(btree_inode->i_mapping,
 155                                               gang[i]);
 156                         if (!page)
 157                                 continue;
 158                         err = write_one_page(page, 0);
 159                         if (err)
 160                                 werr = err;
 161                         page_cache_release(page);
 162                 }
 163         }
 164         err = filemap_fdatawait(btree_inode->i_mapping);
 165         if (err)
 166                 werr = err;
 167         return werr;
 168 }
 169
 170 int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
 171                             struct btrfs_root *root)
 172 {
 173         int ret;
 174         u64 old_extent_block;
 175         struct btrfs_fs_info *fs_info = root->fs_info;
 176         struct btrfs_root *tree_root = fs_info->tree_root;
 177         struct btrfs_root *extent_root = fs_info->extent_root;
 178
 179         btrfs_write_dirty_block_groups(trans, extent_root);
 180         while(1) {
 181                 old_extent_block = btrfs_root_blocknr(&extent_root->root_item);
 182                 if (old_extent_block == bh_blocknr(extent_root->node))
 183                         break;
 184                 btrfs_set_root_blocknr(&extent_root->root_item,
 185                                        bh_blocknr(extent_root->node));
 186                 ret = btrfs_update_root(trans, tree_root,
 187                                         &extent_root->root_key,
 188                                         &extent_root->root_item);
 189                 BUG_ON(ret);
 190                 btrfs_write_dirty_block_groups(trans, extent_root);
 191         }
 192         return 0;
 193 }
 194
 195 static int wait_for_commit(struct btrfs_root *root,
 196                            struct btrfs_transaction *commit)
 197 {
 198         DEFINE_WAIT(wait);
 199         mutex_lock(&root->fs_info->trans_mutex);
 200         while(!commit->commit_done) {
 201                 prepare_to_wait(&commit->commit_wait, &wait,
 202                                 TASK_UNINTERRUPTIBLE);
 203                 if (commit->commit_done)
 204                         break;
 205                 mutex_unlock(&root->fs_info->trans_mutex);
 206                 schedule();
 207                 mutex_lock(&root->fs_info->trans_mutex);
 208         }
 209         mutex_unlock(&root->fs_info->trans_mutex);
 210         finish_wait(&commit->commit_wait, &wait);
 211         return 0;
 212 }
 213
 214 struct dirty_root {
 215         struct list_head list;
 216         struct btrfs_root *root;
 217 };
 218
 219 int btrfs_add_dead_root(struct btrfs_root *root, struct list_head *dead_list)
 220 {
 221         struct dirty_root *dirty;
 222
 223         dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
 224         if (!dirty)
 225                 return -ENOMEM;
 226         dirty->root = root;
 227         list_add(&dirty->list, dead_list);
 228         return 0;
 229 }
 230
 231 static int add_dirty_roots(struct btrfs_trans_handle *trans,
 232                            struct radix_tree_root *radix,
 233                            struct list_head *list)
 234 {
 235         struct dirty_root *dirty;
 236         struct btrfs_root *gang[8];
 237         struct btrfs_root *root;
 238         int i;
 239         int ret;
 240         int err = 0;
 241         u32 refs;
 242
 243         while(1) {
 244                 ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
 245                                                  ARRAY_SIZE(gang),
 246                                                  BTRFS_ROOT_TRANS_TAG);
 247                 if (ret == 0)
 248                         break;
 249                 for (i = 0; i < ret; i++) {
 250                         root = gang[i];
 251                         radix_tree_tag_clear(radix,
 252                                      (unsigned long)root->root_key.objectid,
 253                                      BTRFS_ROOT_TRANS_TAG);
 254                         if (root->commit_root == root->node) {
 255                                 WARN_ON(bh_blocknr(root->node) !=
 256                                         btrfs_root_blocknr(&root->root_item));
 257                                 brelse(root->commit_root);
 258                                 root->commit_root = NULL;
 259                                 continue;
 260                         }
 261                         dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
 262                         BUG_ON(!dirty);
 263                         dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS);
 264                         BUG_ON(!dirty->root);
 265
 266                         memset(&root->root_item.drop_progress, 0,
 267                                sizeof(struct btrfs_disk_key));
 268                         root->root_item.drop_level = 0;
 269
 270                         memcpy(dirty->root, root, sizeof(*root));
 271                         dirty->root->node = root->commit_root;
 272                         root->commit_root = NULL;
 273
 274                         root->root_key.offset = root->fs_info->generation;
 275                         btrfs_set_root_blocknr(&root->root_item,
 276                                                bh_blocknr(root->node));
 277                         err = btrfs_insert_root(trans, root->fs_info->tree_root,
 278                                                 &root->root_key,
 279                                                 &root->root_item);
 280                         if (err)
 281                                 break;
 282
 283                         refs = btrfs_root_refs(&dirty->root->root_item);
 284                         btrfs_set_root_refs(&dirty->root->root_item, refs - 1);
 285                         err = btrfs_update_root(trans, root->fs_info->tree_root,
 286                                                 &dirty->root->root_key,
 287                                                 &dirty->root->root_item);
 288
 289                         BUG_ON(err);
 290                         if (refs == 1) {
 291                                 list_add(&dirty->list, list);
 292                         } else {
 293                                 WARN_ON(1);
 294                                 kfree(dirty->root);
 295                                 kfree(dirty);
 296                         }
 297                 }
 298         }
 299         return err;
 300 }
 301
 302 static int drop_dirty_roots(struct btrfs_root *tree_root,
 303                             struct list_head *list)
 304 {
 305         struct dirty_root *dirty;
 306         struct btrfs_trans_handle *trans;
 307         int ret = 0;
 308         int err;
 309
 310         while(!list_empty(list)) {
 311                 mutex_lock(&tree_root->fs_info->fs_mutex);
 312                 dirty = list_entry(list->next, struct dirty_root, list);
 313                 list_del_init(&dirty->list);
 314
 315                 while(1) {
 316                         trans = btrfs_start_transaction(tree_root, 1);
 317                         ret = btrfs_drop_snapshot(trans, dirty->root);
 318                         if (ret != -EAGAIN) {
 319                                 break;
 320                         }
 321                         err = btrfs_update_root(trans,
 322                                         tree_root,
 323                                         &dirty->root->root_key,
 324                                         &dirty->root->root_item);
 325                         if (err)
 326                                 ret = err;
 327                         ret = btrfs_end_transaction(trans, tree_root);
 328                         BUG_ON(ret);
 329                 }
 330                 BUG_ON(ret);
 331                 ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
 332                 if (ret)
 333                         break;
 334                 ret = btrfs_end_transaction(trans, tree_root);
 335                 BUG_ON(ret);
 336
 337                 kfree(dirty->root);
 338                 kfree(dirty);
 339                 mutex_unlock(&tree_root->fs_info->fs_mutex);
 340                 btrfs_btree_balance_dirty(tree_root);
 341         }
 342         return ret;
 343 }
 344
 345 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
 346                              struct btrfs_root *root)
 347 {
 348         int ret = 0;
 349         struct btrfs_transaction *cur_trans;
 350         struct btrfs_transaction *prev_trans = NULL;
 351         struct list_head dirty_fs_roots;
 352         struct radix_tree_root pinned_copy;
 353         DEFINE_WAIT(wait);
 354
 355         init_bit_radix(&pinned_copy);
 356         INIT_LIST_HEAD(&dirty_fs_roots);
 357
 358         mutex_lock(&root->fs_info->trans_mutex);
 359         if (trans->transaction->in_commit) {
 360                 cur_trans = trans->transaction;
 361                 trans->transaction->use_count++;
 362                 mutex_unlock(&root->fs_info->trans_mutex);
 363                 btrfs_end_transaction(trans, root);
 364
 365                 mutex_unlock(&root->fs_info->fs_mutex);
 366                 ret = wait_for_commit(root, cur_trans);
 367                 BUG_ON(ret);
 368                 put_transaction(cur_trans);
 369                 mutex_lock(&root->fs_info->fs_mutex);
 370                 return 0;
 371         }
 372         trans->transaction->in_commit = 1;
 373         cur_trans = trans->transaction;
 374         if (cur_trans->list.prev != &root->fs_info->trans_list) {
 375                 prev_trans = list_entry(cur_trans->list.prev,
 376                                         struct btrfs_transaction, list);
 377                 if (!prev_trans->commit_done) {
 378                         prev_trans->use_count++;
 379                         mutex_unlock(&root->fs_info->fs_mutex);
 380                         mutex_unlock(&root->fs_info->trans_mutex);
 381
 382                         wait_for_commit(root, prev_trans);
 383                         put_transaction(prev_trans);
 384
 385                         mutex_lock(&root->fs_info->fs_mutex);
 386                         mutex_lock(&root->fs_info->trans_mutex);
 387                 }
 388         }
 389         while (trans->transaction->num_writers > 1) {
 390                 WARN_ON(cur_trans != trans->transaction);
 391                 prepare_to_wait(&trans->transaction->writer_wait, &wait,
 392                                 TASK_UNINTERRUPTIBLE);
 393                 if (trans->transaction->num_writers <= 1)
 394                         break;
 395                 mutex_unlock(&root->fs_info->fs_mutex);
 396                 mutex_unlock(&root->fs_info->trans_mutex);
 397                 schedule();
 398                 mutex_lock(&root->fs_info->fs_mutex);
 399                 mutex_lock(&root->fs_info->trans_mutex);
 400                 finish_wait(&trans->transaction->writer_wait, &wait);
 401         }
 402         finish_wait(&trans->transaction->writer_wait, &wait);
 403         WARN_ON(cur_trans != trans->transaction);
 404         ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix,
 405                               &dirty_fs_roots);
 406         BUG_ON(ret);
 407
 408         ret = btrfs_commit_tree_roots(trans, root);
 409         BUG_ON(ret);
 410
 411         cur_trans = root->fs_info->running_transaction;
 412         root->fs_info->running_transaction = NULL;
 413         btrfs_set_super_generation(&root->fs_info->super_copy,
 414                                    cur_trans->transid);
 415         btrfs_set_super_root(&root->fs_info->super_copy,
 416                              bh_blocknr(root->fs_info->tree_root->node));
 417         memcpy(root->fs_info->disk_super, &root->fs_info->super_copy,
 418                sizeof(root->fs_info->super_copy));
 419
 420         btrfs_copy_pinned(root, &pinned_copy);
 421
 422         mutex_unlock(&root->fs_info->trans_mutex);
 423         mutex_unlock(&root->fs_info->fs_mutex);
 424         ret = btrfs_write_and_wait_transaction(trans, root);
 425         BUG_ON(ret);
 426         write_ctree_super(trans, root);
 427         mutex_lock(&root->fs_info->fs_mutex);
 428         btrfs_finish_extent_commit(trans, root, &pinned_copy);
 429         mutex_lock(&root->fs_info->trans_mutex);
 430         cur_trans->commit_done = 1;
 431         wake_up(&cur_trans->commit_wait);
 432         put_transaction(cur_trans);
 433         put_transaction(cur_trans);
 434         if (root->fs_info->closing)
 435                 list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
 436         else
 437                 list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
 438         mutex_unlock(&root->fs_info->trans_mutex);
 439         kmem_cache_free(btrfs_trans_handle_cachep, trans);
 440
 441         if (root->fs_info->closing) {
 442                 mutex_unlock(&root->fs_info->fs_mutex);
 443                 drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
 444                 mutex_lock(&root->fs_info->fs_mutex);
 445         }
 446         return ret;
 447 }
 448
 449 void btrfs_transaction_cleaner(struct work_struct *work)
 450 {
 451         struct btrfs_fs_info *fs_info = container_of(work,
 452                                                      struct btrfs_fs_info,
 453                                                      trans_work.work);
 454
 455         struct btrfs_root *root = fs_info->tree_root;
 456         struct btrfs_transaction *cur;
 457         struct btrfs_trans_handle *trans;
 458         struct list_head dirty_roots;
 459         unsigned long now;
 460         unsigned long delay = HZ * 30;
 461         int ret;
 462
 463         INIT_LIST_HEAD(&dirty_roots);
 464         mutex_lock(&root->fs_info->fs_mutex);
 465         mutex_lock(&root->fs_info->trans_mutex);
 466         cur = root->fs_info->running_transaction;
 467         if (!cur) {
 468                 mutex_unlock(&root->fs_info->trans_mutex);
 469                 goto out;
 470         }
 471         now = get_seconds();
 472         if (now < cur->start_time || now - cur->start_time < 30) {
 473                 mutex_unlock(&root->fs_info->trans_mutex);
 474                 delay = HZ * 5;
 475                 goto out;
 476         }
 477         mutex_unlock(&root->fs_info->trans_mutex);
 478         trans = btrfs_start_transaction(root, 1);
 479         ret = btrfs_commit_transaction(trans, root);
 480 out:
 481         mutex_unlock(&root->fs_info->fs_mutex);
 482
 483         mutex_lock(&root->fs_info->trans_mutex);
 484         list_splice_init(&root->fs_info->dead_roots, &dirty_roots);
 485         mutex_unlock(&root->fs_info->trans_mutex);
 486
 487         if (!list_empty(&dirty_roots)) {
 488                 drop_dirty_roots(root, &dirty_roots);
 489         }
 490         btrfs_transaction_queue_work(root, delay);
 491 }
 492
 493 void btrfs_transaction_queue_work(struct btrfs_root *root, int delay)
 494 {
 495         queue_delayed_work(trans_wq, &root->fs_info->trans_work, delay);
 496 }
 497
 498 void btrfs_transaction_flush_work(struct btrfs_root *root)
 499 {
 500         cancel_rearming_delayed_workqueue(trans_wq, &root->fs_info->trans_work);
 501         flush_workqueue(trans_wq);
 502 }
 503
 504 void __init btrfs_init_transaction_sys(void)
 505 {
 506         trans_wq = create_workqueue("btrfs");
 507 }
 508
 509 void __exit btrfs_exit_transaction_sys(void)
 510 {
 511         destroy_workqueue(trans_wq);
 512 }
 513