| 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 <linux/writeback.h> |
| 22 | #include <linux/pagemap.h> |
| 23 | #include <linux/blkdev.h> |
| 24 | #include "ctree.h" |
| 25 | #include "disk-io.h" |
| 26 | #include "transaction.h" |
| 27 | #include "locking.h" |
| 28 | #include "tree-log.h" |
| 29 | |
| 30 | #define BTRFS_ROOT_TRANS_TAG 0 |
| 31 | |
| 32 | static noinline void put_transaction(struct btrfs_transaction *transaction) |
| 33 | { |
| 34 | WARN_ON(transaction->use_count == 0); |
| 35 | transaction->use_count--; |
| 36 | if (transaction->use_count == 0) { |
| 37 | list_del_init(&transaction->list); |
| 38 | memset(transaction, 0, sizeof(*transaction)); |
| 39 | kmem_cache_free(btrfs_transaction_cachep, transaction); |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | static noinline void switch_commit_root(struct btrfs_root *root) |
| 44 | { |
| 45 | free_extent_buffer(root->commit_root); |
| 46 | root->commit_root = btrfs_root_node(root); |
| 47 | } |
| 48 | |
| 49 | /* |
| 50 | * either allocate a new transaction or hop into the existing one |
| 51 | */ |
| 52 | static noinline int join_transaction(struct btrfs_root *root) |
| 53 | { |
| 54 | struct btrfs_transaction *cur_trans; |
| 55 | cur_trans = root->fs_info->running_transaction; |
| 56 | if (!cur_trans) { |
| 57 | cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, |
| 58 | GFP_NOFS); |
| 59 | BUG_ON(!cur_trans); |
| 60 | root->fs_info->generation++; |
| 61 | cur_trans->num_writers = 1; |
| 62 | cur_trans->num_joined = 0; |
| 63 | cur_trans->transid = root->fs_info->generation; |
| 64 | init_waitqueue_head(&cur_trans->writer_wait); |
| 65 | init_waitqueue_head(&cur_trans->commit_wait); |
| 66 | cur_trans->in_commit = 0; |
| 67 | cur_trans->blocked = 0; |
| 68 | cur_trans->use_count = 1; |
| 69 | cur_trans->commit_done = 0; |
| 70 | cur_trans->start_time = get_seconds(); |
| 71 | |
| 72 | cur_trans->delayed_refs.root.rb_node = NULL; |
| 73 | cur_trans->delayed_refs.num_entries = 0; |
| 74 | cur_trans->delayed_refs.num_heads_ready = 0; |
| 75 | cur_trans->delayed_refs.num_heads = 0; |
| 76 | cur_trans->delayed_refs.flushing = 0; |
| 77 | cur_trans->delayed_refs.run_delayed_start = 0; |
| 78 | spin_lock_init(&cur_trans->delayed_refs.lock); |
| 79 | |
| 80 | INIT_LIST_HEAD(&cur_trans->pending_snapshots); |
| 81 | list_add_tail(&cur_trans->list, &root->fs_info->trans_list); |
| 82 | extent_io_tree_init(&cur_trans->dirty_pages, |
| 83 | root->fs_info->btree_inode->i_mapping, |
| 84 | GFP_NOFS); |
| 85 | spin_lock(&root->fs_info->new_trans_lock); |
| 86 | root->fs_info->running_transaction = cur_trans; |
| 87 | spin_unlock(&root->fs_info->new_trans_lock); |
| 88 | } else { |
| 89 | cur_trans->num_writers++; |
| 90 | cur_trans->num_joined++; |
| 91 | } |
| 92 | |
| 93 | return 0; |
| 94 | } |
| 95 | |
| 96 | /* |
| 97 | * this does all the record keeping required to make sure that a reference |
| 98 | * counted root is properly recorded in a given transaction. This is required |
| 99 | * to make sure the old root from before we joined the transaction is deleted |
| 100 | * when the transaction commits |
| 101 | */ |
| 102 | static noinline int record_root_in_trans(struct btrfs_trans_handle *trans, |
| 103 | struct btrfs_root *root) |
| 104 | { |
| 105 | if (root->ref_cows && root->last_trans < trans->transid) { |
| 106 | WARN_ON(root == root->fs_info->extent_root); |
| 107 | WARN_ON(root->commit_root != root->node); |
| 108 | |
| 109 | radix_tree_tag_set(&root->fs_info->fs_roots_radix, |
| 110 | (unsigned long)root->root_key.objectid, |
| 111 | BTRFS_ROOT_TRANS_TAG); |
| 112 | root->last_trans = trans->transid; |
| 113 | btrfs_init_reloc_root(trans, root); |
| 114 | } |
| 115 | return 0; |
| 116 | } |
| 117 | |
| 118 | int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans, |
| 119 | struct btrfs_root *root) |
| 120 | { |
| 121 | if (!root->ref_cows) |
| 122 | return 0; |
| 123 | |
| 124 | mutex_lock(&root->fs_info->trans_mutex); |
| 125 | if (root->last_trans == trans->transid) { |
| 126 | mutex_unlock(&root->fs_info->trans_mutex); |
| 127 | return 0; |
| 128 | } |
| 129 | |
| 130 | record_root_in_trans(trans, root); |
| 131 | mutex_unlock(&root->fs_info->trans_mutex); |
| 132 | return 0; |
| 133 | } |
| 134 | |
| 135 | /* wait for commit against the current transaction to become unblocked |
| 136 | * when this is done, it is safe to start a new transaction, but the current |
| 137 | * transaction might not be fully on disk. |
| 138 | */ |
| 139 | static void wait_current_trans(struct btrfs_root *root) |
| 140 | { |
| 141 | struct btrfs_transaction *cur_trans; |
| 142 | |
| 143 | cur_trans = root->fs_info->running_transaction; |
| 144 | if (cur_trans && cur_trans->blocked) { |
| 145 | DEFINE_WAIT(wait); |
| 146 | cur_trans->use_count++; |
| 147 | while (1) { |
| 148 | prepare_to_wait(&root->fs_info->transaction_wait, &wait, |
| 149 | TASK_UNINTERRUPTIBLE); |
| 150 | if (cur_trans->blocked) { |
| 151 | mutex_unlock(&root->fs_info->trans_mutex); |
| 152 | schedule(); |
| 153 | mutex_lock(&root->fs_info->trans_mutex); |
| 154 | finish_wait(&root->fs_info->transaction_wait, |
| 155 | &wait); |
| 156 | } else { |
| 157 | finish_wait(&root->fs_info->transaction_wait, |
| 158 | &wait); |
| 159 | break; |
| 160 | } |
| 161 | } |
| 162 | put_transaction(cur_trans); |
| 163 | } |
| 164 | } |
| 165 | |
| 166 | static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root, |
| 167 | int num_blocks, int wait) |
| 168 | { |
| 169 | struct btrfs_trans_handle *h = |
| 170 | kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS); |
| 171 | int ret; |
| 172 | |
| 173 | mutex_lock(&root->fs_info->trans_mutex); |
| 174 | if (!root->fs_info->log_root_recovering && |
| 175 | ((wait == 1 && !root->fs_info->open_ioctl_trans) || wait == 2)) |
| 176 | wait_current_trans(root); |
| 177 | ret = join_transaction(root); |
| 178 | BUG_ON(ret); |
| 179 | |
| 180 | h->transid = root->fs_info->running_transaction->transid; |
| 181 | h->transaction = root->fs_info->running_transaction; |
| 182 | h->blocks_reserved = num_blocks; |
| 183 | h->blocks_used = 0; |
| 184 | h->block_group = 0; |
| 185 | h->alloc_exclude_nr = 0; |
| 186 | h->alloc_exclude_start = 0; |
| 187 | h->delayed_ref_updates = 0; |
| 188 | |
| 189 | if (!current->journal_info) |
| 190 | current->journal_info = h; |
| 191 | |
| 192 | root->fs_info->running_transaction->use_count++; |
| 193 | record_root_in_trans(h, root); |
| 194 | mutex_unlock(&root->fs_info->trans_mutex); |
| 195 | return h; |
| 196 | } |
| 197 | |
| 198 | struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root, |
| 199 | int num_blocks) |
| 200 | { |
| 201 | return start_transaction(root, num_blocks, 1); |
| 202 | } |
| 203 | struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root, |
| 204 | int num_blocks) |
| 205 | { |
| 206 | return start_transaction(root, num_blocks, 0); |
| 207 | } |
| 208 | |
| 209 | struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r, |
| 210 | int num_blocks) |
| 211 | { |
| 212 | return start_transaction(r, num_blocks, 2); |
| 213 | } |
| 214 | |
| 215 | /* wait for a transaction commit to be fully complete */ |
| 216 | static noinline int wait_for_commit(struct btrfs_root *root, |
| 217 | struct btrfs_transaction *commit) |
| 218 | { |
| 219 | DEFINE_WAIT(wait); |
| 220 | mutex_lock(&root->fs_info->trans_mutex); |
| 221 | while (!commit->commit_done) { |
| 222 | prepare_to_wait(&commit->commit_wait, &wait, |
| 223 | TASK_UNINTERRUPTIBLE); |
| 224 | if (commit->commit_done) |
| 225 | break; |
| 226 | mutex_unlock(&root->fs_info->trans_mutex); |
| 227 | schedule(); |
| 228 | mutex_lock(&root->fs_info->trans_mutex); |
| 229 | } |
| 230 | mutex_unlock(&root->fs_info->trans_mutex); |
| 231 | finish_wait(&commit->commit_wait, &wait); |
| 232 | return 0; |
| 233 | } |
| 234 | |
| 235 | #if 0 |
| 236 | /* |
| 237 | * rate limit against the drop_snapshot code. This helps to slow down new |
| 238 | * operations if the drop_snapshot code isn't able to keep up. |
| 239 | */ |
| 240 | static void throttle_on_drops(struct btrfs_root *root) |
| 241 | { |
| 242 | struct btrfs_fs_info *info = root->fs_info; |
| 243 | int harder_count = 0; |
| 244 | |
| 245 | harder: |
| 246 | if (atomic_read(&info->throttles)) { |
| 247 | DEFINE_WAIT(wait); |
| 248 | int thr; |
| 249 | thr = atomic_read(&info->throttle_gen); |
| 250 | |
| 251 | do { |
| 252 | prepare_to_wait(&info->transaction_throttle, |
| 253 | &wait, TASK_UNINTERRUPTIBLE); |
| 254 | if (!atomic_read(&info->throttles)) { |
| 255 | finish_wait(&info->transaction_throttle, &wait); |
| 256 | break; |
| 257 | } |
| 258 | schedule(); |
| 259 | finish_wait(&info->transaction_throttle, &wait); |
| 260 | } while (thr == atomic_read(&info->throttle_gen)); |
| 261 | harder_count++; |
| 262 | |
| 263 | if (root->fs_info->total_ref_cache_size > 1 * 1024 * 1024 && |
| 264 | harder_count < 2) |
| 265 | goto harder; |
| 266 | |
| 267 | if (root->fs_info->total_ref_cache_size > 5 * 1024 * 1024 && |
| 268 | harder_count < 10) |
| 269 | goto harder; |
| 270 | |
| 271 | if (root->fs_info->total_ref_cache_size > 10 * 1024 * 1024 && |
| 272 | harder_count < 20) |
| 273 | goto harder; |
| 274 | } |
| 275 | } |
| 276 | #endif |
| 277 | |
| 278 | void btrfs_throttle(struct btrfs_root *root) |
| 279 | { |
| 280 | mutex_lock(&root->fs_info->trans_mutex); |
| 281 | if (!root->fs_info->open_ioctl_trans) |
| 282 | wait_current_trans(root); |
| 283 | mutex_unlock(&root->fs_info->trans_mutex); |
| 284 | } |
| 285 | |
| 286 | static int __btrfs_end_transaction(struct btrfs_trans_handle *trans, |
| 287 | struct btrfs_root *root, int throttle) |
| 288 | { |
| 289 | struct btrfs_transaction *cur_trans; |
| 290 | struct btrfs_fs_info *info = root->fs_info; |
| 291 | int count = 0; |
| 292 | |
| 293 | while (count < 4) { |
| 294 | unsigned long cur = trans->delayed_ref_updates; |
| 295 | trans->delayed_ref_updates = 0; |
| 296 | if (cur && |
| 297 | trans->transaction->delayed_refs.num_heads_ready > 64) { |
| 298 | trans->delayed_ref_updates = 0; |
| 299 | |
| 300 | /* |
| 301 | * do a full flush if the transaction is trying |
| 302 | * to close |
| 303 | */ |
| 304 | if (trans->transaction->delayed_refs.flushing) |
| 305 | cur = 0; |
| 306 | btrfs_run_delayed_refs(trans, root, cur); |
| 307 | } else { |
| 308 | break; |
| 309 | } |
| 310 | count++; |
| 311 | } |
| 312 | |
| 313 | mutex_lock(&info->trans_mutex); |
| 314 | cur_trans = info->running_transaction; |
| 315 | WARN_ON(cur_trans != trans->transaction); |
| 316 | WARN_ON(cur_trans->num_writers < 1); |
| 317 | cur_trans->num_writers--; |
| 318 | |
| 319 | if (waitqueue_active(&cur_trans->writer_wait)) |
| 320 | wake_up(&cur_trans->writer_wait); |
| 321 | put_transaction(cur_trans); |
| 322 | mutex_unlock(&info->trans_mutex); |
| 323 | |
| 324 | if (current->journal_info == trans) |
| 325 | current->journal_info = NULL; |
| 326 | memset(trans, 0, sizeof(*trans)); |
| 327 | kmem_cache_free(btrfs_trans_handle_cachep, trans); |
| 328 | |
| 329 | return 0; |
| 330 | } |
| 331 | |
| 332 | int btrfs_end_transaction(struct btrfs_trans_handle *trans, |
| 333 | struct btrfs_root *root) |
| 334 | { |
| 335 | return __btrfs_end_transaction(trans, root, 0); |
| 336 | } |
| 337 | |
| 338 | int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans, |
| 339 | struct btrfs_root *root) |
| 340 | { |
| 341 | return __btrfs_end_transaction(trans, root, 1); |
| 342 | } |
| 343 | |
| 344 | /* |
| 345 | * when btree blocks are allocated, they have some corresponding bits set for |
| 346 | * them in one of two extent_io trees. This is used to make sure all of |
| 347 | * those extents are on disk for transaction or log commit |
| 348 | */ |
| 349 | int btrfs_write_and_wait_marked_extents(struct btrfs_root *root, |
| 350 | struct extent_io_tree *dirty_pages) |
| 351 | { |
| 352 | int ret; |
| 353 | int err = 0; |
| 354 | int werr = 0; |
| 355 | struct page *page; |
| 356 | struct inode *btree_inode = root->fs_info->btree_inode; |
| 357 | u64 start = 0; |
| 358 | u64 end; |
| 359 | unsigned long index; |
| 360 | |
| 361 | while (1) { |
| 362 | ret = find_first_extent_bit(dirty_pages, start, &start, &end, |
| 363 | EXTENT_DIRTY); |
| 364 | if (ret) |
| 365 | break; |
| 366 | while (start <= end) { |
| 367 | cond_resched(); |
| 368 | |
| 369 | index = start >> PAGE_CACHE_SHIFT; |
| 370 | start = (u64)(index + 1) << PAGE_CACHE_SHIFT; |
| 371 | page = find_get_page(btree_inode->i_mapping, index); |
| 372 | if (!page) |
| 373 | continue; |
| 374 | |
| 375 | btree_lock_page_hook(page); |
| 376 | if (!page->mapping) { |
| 377 | unlock_page(page); |
| 378 | page_cache_release(page); |
| 379 | continue; |
| 380 | } |
| 381 | |
| 382 | if (PageWriteback(page)) { |
| 383 | if (PageDirty(page)) |
| 384 | wait_on_page_writeback(page); |
| 385 | else { |
| 386 | unlock_page(page); |
| 387 | page_cache_release(page); |
| 388 | continue; |
| 389 | } |
| 390 | } |
| 391 | err = write_one_page(page, 0); |
| 392 | if (err) |
| 393 | werr = err; |
| 394 | page_cache_release(page); |
| 395 | } |
| 396 | } |
| 397 | while (1) { |
| 398 | ret = find_first_extent_bit(dirty_pages, 0, &start, &end, |
| 399 | EXTENT_DIRTY); |
| 400 | if (ret) |
| 401 | break; |
| 402 | |
| 403 | clear_extent_dirty(dirty_pages, start, end, GFP_NOFS); |
| 404 | while (start <= end) { |
| 405 | index = start >> PAGE_CACHE_SHIFT; |
| 406 | start = (u64)(index + 1) << PAGE_CACHE_SHIFT; |
| 407 | page = find_get_page(btree_inode->i_mapping, index); |
| 408 | if (!page) |
| 409 | continue; |
| 410 | if (PageDirty(page)) { |
| 411 | btree_lock_page_hook(page); |
| 412 | wait_on_page_writeback(page); |
| 413 | err = write_one_page(page, 0); |
| 414 | if (err) |
| 415 | werr = err; |
| 416 | } |
| 417 | wait_on_page_writeback(page); |
| 418 | page_cache_release(page); |
| 419 | cond_resched(); |
| 420 | } |
| 421 | } |
| 422 | if (err) |
| 423 | werr = err; |
| 424 | return werr; |
| 425 | } |
| 426 | |
| 427 | int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans, |
| 428 | struct btrfs_root *root) |
| 429 | { |
| 430 | if (!trans || !trans->transaction) { |
| 431 | struct inode *btree_inode; |
| 432 | btree_inode = root->fs_info->btree_inode; |
| 433 | return filemap_write_and_wait(btree_inode->i_mapping); |
| 434 | } |
| 435 | return btrfs_write_and_wait_marked_extents(root, |
| 436 | &trans->transaction->dirty_pages); |
| 437 | } |
| 438 | |
| 439 | /* |
| 440 | * this is used to update the root pointer in the tree of tree roots. |
| 441 | * |
| 442 | * But, in the case of the extent allocation tree, updating the root |
| 443 | * pointer may allocate blocks which may change the root of the extent |
| 444 | * allocation tree. |
| 445 | * |
| 446 | * So, this loops and repeats and makes sure the cowonly root didn't |
| 447 | * change while the root pointer was being updated in the metadata. |
| 448 | */ |
| 449 | static int update_cowonly_root(struct btrfs_trans_handle *trans, |
| 450 | struct btrfs_root *root) |
| 451 | { |
| 452 | int ret; |
| 453 | u64 old_root_bytenr; |
| 454 | struct btrfs_root *tree_root = root->fs_info->tree_root; |
| 455 | |
| 456 | btrfs_write_dirty_block_groups(trans, root); |
| 457 | |
| 458 | while (1) { |
| 459 | old_root_bytenr = btrfs_root_bytenr(&root->root_item); |
| 460 | if (old_root_bytenr == root->node->start) |
| 461 | break; |
| 462 | |
| 463 | btrfs_set_root_node(&root->root_item, root->node); |
| 464 | ret = btrfs_update_root(trans, tree_root, |
| 465 | &root->root_key, |
| 466 | &root->root_item); |
| 467 | BUG_ON(ret); |
| 468 | |
| 469 | ret = btrfs_write_dirty_block_groups(trans, root); |
| 470 | BUG_ON(ret); |
| 471 | } |
| 472 | |
| 473 | if (root != root->fs_info->extent_root) |
| 474 | switch_commit_root(root); |
| 475 | |
| 476 | return 0; |
| 477 | } |
| 478 | |
| 479 | /* |
| 480 | * update all the cowonly tree roots on disk |
| 481 | */ |
| 482 | static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans, |
| 483 | struct btrfs_root *root) |
| 484 | { |
| 485 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 486 | struct list_head *next; |
| 487 | struct extent_buffer *eb; |
| 488 | int ret; |
| 489 | |
| 490 | ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); |
| 491 | BUG_ON(ret); |
| 492 | |
| 493 | eb = btrfs_lock_root_node(fs_info->tree_root); |
| 494 | btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb); |
| 495 | btrfs_tree_unlock(eb); |
| 496 | free_extent_buffer(eb); |
| 497 | |
| 498 | ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); |
| 499 | BUG_ON(ret); |
| 500 | |
| 501 | while (!list_empty(&fs_info->dirty_cowonly_roots)) { |
| 502 | next = fs_info->dirty_cowonly_roots.next; |
| 503 | list_del_init(next); |
| 504 | root = list_entry(next, struct btrfs_root, dirty_list); |
| 505 | |
| 506 | update_cowonly_root(trans, root); |
| 507 | } |
| 508 | |
| 509 | down_write(&fs_info->extent_commit_sem); |
| 510 | switch_commit_root(fs_info->extent_root); |
| 511 | up_write(&fs_info->extent_commit_sem); |
| 512 | |
| 513 | return 0; |
| 514 | } |
| 515 | |
| 516 | /* |
| 517 | * dead roots are old snapshots that need to be deleted. This allocates |
| 518 | * a dirty root struct and adds it into the list of dead roots that need to |
| 519 | * be deleted |
| 520 | */ |
| 521 | int btrfs_add_dead_root(struct btrfs_root *root) |
| 522 | { |
| 523 | mutex_lock(&root->fs_info->trans_mutex); |
| 524 | list_add(&root->root_list, &root->fs_info->dead_roots); |
| 525 | mutex_unlock(&root->fs_info->trans_mutex); |
| 526 | return 0; |
| 527 | } |
| 528 | |
| 529 | /* |
| 530 | * update all the cowonly tree roots on disk |
| 531 | */ |
| 532 | static noinline int commit_fs_roots(struct btrfs_trans_handle *trans, |
| 533 | struct btrfs_root *root) |
| 534 | { |
| 535 | struct btrfs_root *gang[8]; |
| 536 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 537 | int i; |
| 538 | int ret; |
| 539 | int err = 0; |
| 540 | |
| 541 | while (1) { |
| 542 | ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix, |
| 543 | (void **)gang, 0, |
| 544 | ARRAY_SIZE(gang), |
| 545 | BTRFS_ROOT_TRANS_TAG); |
| 546 | if (ret == 0) |
| 547 | break; |
| 548 | for (i = 0; i < ret; i++) { |
| 549 | root = gang[i]; |
| 550 | radix_tree_tag_clear(&fs_info->fs_roots_radix, |
| 551 | (unsigned long)root->root_key.objectid, |
| 552 | BTRFS_ROOT_TRANS_TAG); |
| 553 | |
| 554 | btrfs_free_log(trans, root); |
| 555 | btrfs_update_reloc_root(trans, root); |
| 556 | |
| 557 | if (root->commit_root != root->node) { |
| 558 | switch_commit_root(root); |
| 559 | btrfs_set_root_node(&root->root_item, |
| 560 | root->node); |
| 561 | } |
| 562 | |
| 563 | err = btrfs_update_root(trans, fs_info->tree_root, |
| 564 | &root->root_key, |
| 565 | &root->root_item); |
| 566 | if (err) |
| 567 | break; |
| 568 | } |
| 569 | } |
| 570 | return err; |
| 571 | } |
| 572 | |
| 573 | /* |
| 574 | * defrag a given btree. If cacheonly == 1, this won't read from the disk, |
| 575 | * otherwise every leaf in the btree is read and defragged. |
| 576 | */ |
| 577 | int btrfs_defrag_root(struct btrfs_root *root, int cacheonly) |
| 578 | { |
| 579 | struct btrfs_fs_info *info = root->fs_info; |
| 580 | int ret; |
| 581 | struct btrfs_trans_handle *trans; |
| 582 | unsigned long nr; |
| 583 | |
| 584 | smp_mb(); |
| 585 | if (root->defrag_running) |
| 586 | return 0; |
| 587 | trans = btrfs_start_transaction(root, 1); |
| 588 | while (1) { |
| 589 | root->defrag_running = 1; |
| 590 | ret = btrfs_defrag_leaves(trans, root, cacheonly); |
| 591 | nr = trans->blocks_used; |
| 592 | btrfs_end_transaction(trans, root); |
| 593 | btrfs_btree_balance_dirty(info->tree_root, nr); |
| 594 | cond_resched(); |
| 595 | |
| 596 | trans = btrfs_start_transaction(root, 1); |
| 597 | if (root->fs_info->closing || ret != -EAGAIN) |
| 598 | break; |
| 599 | } |
| 600 | root->defrag_running = 0; |
| 601 | smp_mb(); |
| 602 | btrfs_end_transaction(trans, root); |
| 603 | return 0; |
| 604 | } |
| 605 | |
| 606 | #if 0 |
| 607 | /* |
| 608 | * when dropping snapshots, we generate a ton of delayed refs, and it makes |
| 609 | * sense not to join the transaction while it is trying to flush the current |
| 610 | * queue of delayed refs out. |
| 611 | * |
| 612 | * This is used by the drop snapshot code only |
| 613 | */ |
| 614 | static noinline int wait_transaction_pre_flush(struct btrfs_fs_info *info) |
| 615 | { |
| 616 | DEFINE_WAIT(wait); |
| 617 | |
| 618 | mutex_lock(&info->trans_mutex); |
| 619 | while (info->running_transaction && |
| 620 | info->running_transaction->delayed_refs.flushing) { |
| 621 | prepare_to_wait(&info->transaction_wait, &wait, |
| 622 | TASK_UNINTERRUPTIBLE); |
| 623 | mutex_unlock(&info->trans_mutex); |
| 624 | |
| 625 | schedule(); |
| 626 | |
| 627 | mutex_lock(&info->trans_mutex); |
| 628 | finish_wait(&info->transaction_wait, &wait); |
| 629 | } |
| 630 | mutex_unlock(&info->trans_mutex); |
| 631 | return 0; |
| 632 | } |
| 633 | |
| 634 | /* |
| 635 | * Given a list of roots that need to be deleted, call btrfs_drop_snapshot on |
| 636 | * all of them |
| 637 | */ |
| 638 | int btrfs_drop_dead_root(struct btrfs_root *root) |
| 639 | { |
| 640 | struct btrfs_trans_handle *trans; |
| 641 | struct btrfs_root *tree_root = root->fs_info->tree_root; |
| 642 | unsigned long nr; |
| 643 | int ret; |
| 644 | |
| 645 | while (1) { |
| 646 | /* |
| 647 | * we don't want to jump in and create a bunch of |
| 648 | * delayed refs if the transaction is starting to close |
| 649 | */ |
| 650 | wait_transaction_pre_flush(tree_root->fs_info); |
| 651 | trans = btrfs_start_transaction(tree_root, 1); |
| 652 | |
| 653 | /* |
| 654 | * we've joined a transaction, make sure it isn't |
| 655 | * closing right now |
| 656 | */ |
| 657 | if (trans->transaction->delayed_refs.flushing) { |
| 658 | btrfs_end_transaction(trans, tree_root); |
| 659 | continue; |
| 660 | } |
| 661 | |
| 662 | ret = btrfs_drop_snapshot(trans, root); |
| 663 | if (ret != -EAGAIN) |
| 664 | break; |
| 665 | |
| 666 | ret = btrfs_update_root(trans, tree_root, |
| 667 | &root->root_key, |
| 668 | &root->root_item); |
| 669 | if (ret) |
| 670 | break; |
| 671 | |
| 672 | nr = trans->blocks_used; |
| 673 | ret = btrfs_end_transaction(trans, tree_root); |
| 674 | BUG_ON(ret); |
| 675 | |
| 676 | btrfs_btree_balance_dirty(tree_root, nr); |
| 677 | cond_resched(); |
| 678 | } |
| 679 | BUG_ON(ret); |
| 680 | |
| 681 | ret = btrfs_del_root(trans, tree_root, &root->root_key); |
| 682 | BUG_ON(ret); |
| 683 | |
| 684 | nr = trans->blocks_used; |
| 685 | ret = btrfs_end_transaction(trans, tree_root); |
| 686 | BUG_ON(ret); |
| 687 | |
| 688 | free_extent_buffer(root->node); |
| 689 | free_extent_buffer(root->commit_root); |
| 690 | kfree(root); |
| 691 | |
| 692 | btrfs_btree_balance_dirty(tree_root, nr); |
| 693 | return ret; |
| 694 | } |
| 695 | #endif |
| 696 | |
| 697 | /* |
| 698 | * new snapshots need to be created at a very specific time in the |
| 699 | * transaction commit. This does the actual creation |
| 700 | */ |
| 701 | static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans, |
| 702 | struct btrfs_fs_info *fs_info, |
| 703 | struct btrfs_pending_snapshot *pending) |
| 704 | { |
| 705 | struct btrfs_key key; |
| 706 | struct btrfs_root_item *new_root_item; |
| 707 | struct btrfs_root *tree_root = fs_info->tree_root; |
| 708 | struct btrfs_root *root = pending->root; |
| 709 | struct extent_buffer *tmp; |
| 710 | struct extent_buffer *old; |
| 711 | int ret; |
| 712 | u64 objectid; |
| 713 | |
| 714 | new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS); |
| 715 | if (!new_root_item) { |
| 716 | ret = -ENOMEM; |
| 717 | goto fail; |
| 718 | } |
| 719 | ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid); |
| 720 | if (ret) |
| 721 | goto fail; |
| 722 | |
| 723 | record_root_in_trans(trans, root); |
| 724 | btrfs_set_root_last_snapshot(&root->root_item, trans->transid); |
| 725 | memcpy(new_root_item, &root->root_item, sizeof(*new_root_item)); |
| 726 | |
| 727 | key.objectid = objectid; |
| 728 | /* record when the snapshot was created in key.offset */ |
| 729 | key.offset = trans->transid; |
| 730 | btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY); |
| 731 | |
| 732 | old = btrfs_lock_root_node(root); |
| 733 | btrfs_cow_block(trans, root, old, NULL, 0, &old); |
| 734 | btrfs_set_lock_blocking(old); |
| 735 | |
| 736 | btrfs_copy_root(trans, root, old, &tmp, objectid); |
| 737 | btrfs_tree_unlock(old); |
| 738 | free_extent_buffer(old); |
| 739 | |
| 740 | btrfs_set_root_node(new_root_item, tmp); |
| 741 | ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key, |
| 742 | new_root_item); |
| 743 | btrfs_tree_unlock(tmp); |
| 744 | free_extent_buffer(tmp); |
| 745 | if (ret) |
| 746 | goto fail; |
| 747 | |
| 748 | key.offset = (u64)-1; |
| 749 | memcpy(&pending->root_key, &key, sizeof(key)); |
| 750 | fail: |
| 751 | kfree(new_root_item); |
| 752 | btrfs_unreserve_metadata_space(root, 6); |
| 753 | return ret; |
| 754 | } |
| 755 | |
| 756 | static noinline int finish_pending_snapshot(struct btrfs_fs_info *fs_info, |
| 757 | struct btrfs_pending_snapshot *pending) |
| 758 | { |
| 759 | int ret; |
| 760 | int namelen; |
| 761 | u64 index = 0; |
| 762 | struct btrfs_trans_handle *trans; |
| 763 | struct inode *parent_inode; |
| 764 | struct inode *inode; |
| 765 | struct btrfs_root *parent_root; |
| 766 | |
| 767 | parent_inode = pending->dentry->d_parent->d_inode; |
| 768 | parent_root = BTRFS_I(parent_inode)->root; |
| 769 | trans = btrfs_join_transaction(parent_root, 1); |
| 770 | |
| 771 | /* |
| 772 | * insert the directory item |
| 773 | */ |
| 774 | namelen = strlen(pending->name); |
| 775 | ret = btrfs_set_inode_index(parent_inode, &index); |
| 776 | ret = btrfs_insert_dir_item(trans, parent_root, |
| 777 | pending->name, namelen, |
| 778 | parent_inode->i_ino, |
| 779 | &pending->root_key, BTRFS_FT_DIR, index); |
| 780 | |
| 781 | if (ret) |
| 782 | goto fail; |
| 783 | |
| 784 | btrfs_i_size_write(parent_inode, parent_inode->i_size + namelen * 2); |
| 785 | ret = btrfs_update_inode(trans, parent_root, parent_inode); |
| 786 | BUG_ON(ret); |
| 787 | |
| 788 | ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root, |
| 789 | pending->root_key.objectid, |
| 790 | parent_root->root_key.objectid, |
| 791 | parent_inode->i_ino, index, pending->name, |
| 792 | namelen); |
| 793 | |
| 794 | BUG_ON(ret); |
| 795 | |
| 796 | inode = btrfs_lookup_dentry(parent_inode, pending->dentry); |
| 797 | d_instantiate(pending->dentry, inode); |
| 798 | fail: |
| 799 | btrfs_end_transaction(trans, fs_info->fs_root); |
| 800 | return ret; |
| 801 | } |
| 802 | |
| 803 | /* |
| 804 | * create all the snapshots we've scheduled for creation |
| 805 | */ |
| 806 | static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans, |
| 807 | struct btrfs_fs_info *fs_info) |
| 808 | { |
| 809 | struct btrfs_pending_snapshot *pending; |
| 810 | struct list_head *head = &trans->transaction->pending_snapshots; |
| 811 | int ret; |
| 812 | |
| 813 | list_for_each_entry(pending, head, list) { |
| 814 | ret = create_pending_snapshot(trans, fs_info, pending); |
| 815 | BUG_ON(ret); |
| 816 | } |
| 817 | return 0; |
| 818 | } |
| 819 | |
| 820 | static noinline int finish_pending_snapshots(struct btrfs_trans_handle *trans, |
| 821 | struct btrfs_fs_info *fs_info) |
| 822 | { |
| 823 | struct btrfs_pending_snapshot *pending; |
| 824 | struct list_head *head = &trans->transaction->pending_snapshots; |
| 825 | int ret; |
| 826 | |
| 827 | while (!list_empty(head)) { |
| 828 | pending = list_entry(head->next, |
| 829 | struct btrfs_pending_snapshot, list); |
| 830 | ret = finish_pending_snapshot(fs_info, pending); |
| 831 | BUG_ON(ret); |
| 832 | list_del(&pending->list); |
| 833 | kfree(pending->name); |
| 834 | kfree(pending); |
| 835 | } |
| 836 | return 0; |
| 837 | } |
| 838 | |
| 839 | static void update_super_roots(struct btrfs_root *root) |
| 840 | { |
| 841 | struct btrfs_root_item *root_item; |
| 842 | struct btrfs_super_block *super; |
| 843 | |
| 844 | super = &root->fs_info->super_copy; |
| 845 | |
| 846 | root_item = &root->fs_info->chunk_root->root_item; |
| 847 | super->chunk_root = root_item->bytenr; |
| 848 | super->chunk_root_generation = root_item->generation; |
| 849 | super->chunk_root_level = root_item->level; |
| 850 | |
| 851 | root_item = &root->fs_info->tree_root->root_item; |
| 852 | super->root = root_item->bytenr; |
| 853 | super->generation = root_item->generation; |
| 854 | super->root_level = root_item->level; |
| 855 | } |
| 856 | |
| 857 | int btrfs_transaction_in_commit(struct btrfs_fs_info *info) |
| 858 | { |
| 859 | int ret = 0; |
| 860 | spin_lock(&info->new_trans_lock); |
| 861 | if (info->running_transaction) |
| 862 | ret = info->running_transaction->in_commit; |
| 863 | spin_unlock(&info->new_trans_lock); |
| 864 | return ret; |
| 865 | } |
| 866 | |
| 867 | int btrfs_commit_transaction(struct btrfs_trans_handle *trans, |
| 868 | struct btrfs_root *root) |
| 869 | { |
| 870 | unsigned long joined = 0; |
| 871 | unsigned long timeout = 1; |
| 872 | struct btrfs_transaction *cur_trans; |
| 873 | struct btrfs_transaction *prev_trans = NULL; |
| 874 | DEFINE_WAIT(wait); |
| 875 | int ret; |
| 876 | int should_grow = 0; |
| 877 | unsigned long now = get_seconds(); |
| 878 | int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT); |
| 879 | |
| 880 | btrfs_run_ordered_operations(root, 0); |
| 881 | |
| 882 | /* make a pass through all the delayed refs we have so far |
| 883 | * any runnings procs may add more while we are here |
| 884 | */ |
| 885 | ret = btrfs_run_delayed_refs(trans, root, 0); |
| 886 | BUG_ON(ret); |
| 887 | |
| 888 | cur_trans = trans->transaction; |
| 889 | /* |
| 890 | * set the flushing flag so procs in this transaction have to |
| 891 | * start sending their work down. |
| 892 | */ |
| 893 | cur_trans->delayed_refs.flushing = 1; |
| 894 | |
| 895 | ret = btrfs_run_delayed_refs(trans, root, 0); |
| 896 | BUG_ON(ret); |
| 897 | |
| 898 | mutex_lock(&root->fs_info->trans_mutex); |
| 899 | if (cur_trans->in_commit) { |
| 900 | cur_trans->use_count++; |
| 901 | mutex_unlock(&root->fs_info->trans_mutex); |
| 902 | btrfs_end_transaction(trans, root); |
| 903 | |
| 904 | ret = wait_for_commit(root, cur_trans); |
| 905 | BUG_ON(ret); |
| 906 | |
| 907 | mutex_lock(&root->fs_info->trans_mutex); |
| 908 | put_transaction(cur_trans); |
| 909 | mutex_unlock(&root->fs_info->trans_mutex); |
| 910 | |
| 911 | return 0; |
| 912 | } |
| 913 | |
| 914 | trans->transaction->in_commit = 1; |
| 915 | trans->transaction->blocked = 1; |
| 916 | if (cur_trans->list.prev != &root->fs_info->trans_list) { |
| 917 | prev_trans = list_entry(cur_trans->list.prev, |
| 918 | struct btrfs_transaction, list); |
| 919 | if (!prev_trans->commit_done) { |
| 920 | prev_trans->use_count++; |
| 921 | mutex_unlock(&root->fs_info->trans_mutex); |
| 922 | |
| 923 | wait_for_commit(root, prev_trans); |
| 924 | |
| 925 | mutex_lock(&root->fs_info->trans_mutex); |
| 926 | put_transaction(prev_trans); |
| 927 | } |
| 928 | } |
| 929 | |
| 930 | if (now < cur_trans->start_time || now - cur_trans->start_time < 1) |
| 931 | should_grow = 1; |
| 932 | |
| 933 | do { |
| 934 | int snap_pending = 0; |
| 935 | joined = cur_trans->num_joined; |
| 936 | if (!list_empty(&trans->transaction->pending_snapshots)) |
| 937 | snap_pending = 1; |
| 938 | |
| 939 | WARN_ON(cur_trans != trans->transaction); |
| 940 | prepare_to_wait(&cur_trans->writer_wait, &wait, |
| 941 | TASK_UNINTERRUPTIBLE); |
| 942 | |
| 943 | if (cur_trans->num_writers > 1) |
| 944 | timeout = MAX_SCHEDULE_TIMEOUT; |
| 945 | else if (should_grow) |
| 946 | timeout = 1; |
| 947 | |
| 948 | mutex_unlock(&root->fs_info->trans_mutex); |
| 949 | |
| 950 | if (flush_on_commit) { |
| 951 | btrfs_start_delalloc_inodes(root); |
| 952 | ret = btrfs_wait_ordered_extents(root, 0); |
| 953 | BUG_ON(ret); |
| 954 | } else if (snap_pending) { |
| 955 | ret = btrfs_wait_ordered_extents(root, 1); |
| 956 | BUG_ON(ret); |
| 957 | } |
| 958 | |
| 959 | /* |
| 960 | * rename don't use btrfs_join_transaction, so, once we |
| 961 | * set the transaction to blocked above, we aren't going |
| 962 | * to get any new ordered operations. We can safely run |
| 963 | * it here and no for sure that nothing new will be added |
| 964 | * to the list |
| 965 | */ |
| 966 | btrfs_run_ordered_operations(root, 1); |
| 967 | |
| 968 | smp_mb(); |
| 969 | if (cur_trans->num_writers > 1 || should_grow) |
| 970 | schedule_timeout(timeout); |
| 971 | |
| 972 | mutex_lock(&root->fs_info->trans_mutex); |
| 973 | finish_wait(&cur_trans->writer_wait, &wait); |
| 974 | } while (cur_trans->num_writers > 1 || |
| 975 | (should_grow && cur_trans->num_joined != joined)); |
| 976 | |
| 977 | ret = create_pending_snapshots(trans, root->fs_info); |
| 978 | BUG_ON(ret); |
| 979 | |
| 980 | ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1); |
| 981 | BUG_ON(ret); |
| 982 | |
| 983 | WARN_ON(cur_trans != trans->transaction); |
| 984 | |
| 985 | /* btrfs_commit_tree_roots is responsible for getting the |
| 986 | * various roots consistent with each other. Every pointer |
| 987 | * in the tree of tree roots has to point to the most up to date |
| 988 | * root for every subvolume and other tree. So, we have to keep |
| 989 | * the tree logging code from jumping in and changing any |
| 990 | * of the trees. |
| 991 | * |
| 992 | * At this point in the commit, there can't be any tree-log |
| 993 | * writers, but a little lower down we drop the trans mutex |
| 994 | * and let new people in. By holding the tree_log_mutex |
| 995 | * from now until after the super is written, we avoid races |
| 996 | * with the tree-log code. |
| 997 | */ |
| 998 | mutex_lock(&root->fs_info->tree_log_mutex); |
| 999 | |
| 1000 | ret = commit_fs_roots(trans, root); |
| 1001 | BUG_ON(ret); |
| 1002 | |
| 1003 | /* commit_fs_roots gets rid of all the tree log roots, it is now |
| 1004 | * safe to free the root of tree log roots |
| 1005 | */ |
| 1006 | btrfs_free_log_root_tree(trans, root->fs_info); |
| 1007 | |
| 1008 | ret = commit_cowonly_roots(trans, root); |
| 1009 | BUG_ON(ret); |
| 1010 | |
| 1011 | btrfs_prepare_extent_commit(trans, root); |
| 1012 | |
| 1013 | cur_trans = root->fs_info->running_transaction; |
| 1014 | spin_lock(&root->fs_info->new_trans_lock); |
| 1015 | root->fs_info->running_transaction = NULL; |
| 1016 | spin_unlock(&root->fs_info->new_trans_lock); |
| 1017 | |
| 1018 | btrfs_set_root_node(&root->fs_info->tree_root->root_item, |
| 1019 | root->fs_info->tree_root->node); |
| 1020 | switch_commit_root(root->fs_info->tree_root); |
| 1021 | |
| 1022 | btrfs_set_root_node(&root->fs_info->chunk_root->root_item, |
| 1023 | root->fs_info->chunk_root->node); |
| 1024 | switch_commit_root(root->fs_info->chunk_root); |
| 1025 | |
| 1026 | update_super_roots(root); |
| 1027 | |
| 1028 | if (!root->fs_info->log_root_recovering) { |
| 1029 | btrfs_set_super_log_root(&root->fs_info->super_copy, 0); |
| 1030 | btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0); |
| 1031 | } |
| 1032 | |
| 1033 | memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy, |
| 1034 | sizeof(root->fs_info->super_copy)); |
| 1035 | |
| 1036 | trans->transaction->blocked = 0; |
| 1037 | |
| 1038 | wake_up(&root->fs_info->transaction_wait); |
| 1039 | |
| 1040 | mutex_unlock(&root->fs_info->trans_mutex); |
| 1041 | ret = btrfs_write_and_wait_transaction(trans, root); |
| 1042 | BUG_ON(ret); |
| 1043 | write_ctree_super(trans, root, 0); |
| 1044 | |
| 1045 | /* |
| 1046 | * the super is written, we can safely allow the tree-loggers |
| 1047 | * to go about their business |
| 1048 | */ |
| 1049 | mutex_unlock(&root->fs_info->tree_log_mutex); |
| 1050 | |
| 1051 | btrfs_finish_extent_commit(trans, root); |
| 1052 | |
| 1053 | /* do the directory inserts of any pending snapshot creations */ |
| 1054 | finish_pending_snapshots(trans, root->fs_info); |
| 1055 | |
| 1056 | mutex_lock(&root->fs_info->trans_mutex); |
| 1057 | |
| 1058 | cur_trans->commit_done = 1; |
| 1059 | |
| 1060 | root->fs_info->last_trans_committed = cur_trans->transid; |
| 1061 | |
| 1062 | wake_up(&cur_trans->commit_wait); |
| 1063 | |
| 1064 | put_transaction(cur_trans); |
| 1065 | put_transaction(cur_trans); |
| 1066 | |
| 1067 | mutex_unlock(&root->fs_info->trans_mutex); |
| 1068 | |
| 1069 | if (current->journal_info == trans) |
| 1070 | current->journal_info = NULL; |
| 1071 | |
| 1072 | kmem_cache_free(btrfs_trans_handle_cachep, trans); |
| 1073 | return ret; |
| 1074 | } |
| 1075 | |
| 1076 | /* |
| 1077 | * interface function to delete all the snapshots we have scheduled for deletion |
| 1078 | */ |
| 1079 | int btrfs_clean_old_snapshots(struct btrfs_root *root) |
| 1080 | { |
| 1081 | LIST_HEAD(list); |
| 1082 | struct btrfs_fs_info *fs_info = root->fs_info; |
| 1083 | |
| 1084 | mutex_lock(&fs_info->trans_mutex); |
| 1085 | list_splice_init(&fs_info->dead_roots, &list); |
| 1086 | mutex_unlock(&fs_info->trans_mutex); |
| 1087 | |
| 1088 | while (!list_empty(&list)) { |
| 1089 | root = list_entry(list.next, struct btrfs_root, root_list); |
| 1090 | list_del(&root->root_list); |
| 1091 | |
| 1092 | if (btrfs_header_backref_rev(root->node) < |
| 1093 | BTRFS_MIXED_BACKREF_REV) |
| 1094 | btrfs_drop_snapshot(root, 0); |
| 1095 | else |
| 1096 | btrfs_drop_snapshot(root, 1); |
| 1097 | } |
| 1098 | return 0; |
| 1099 | } |