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