1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * linux/fs/jbd2/commit.c 4 * 5 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998 6 * 7 * Copyright 1998 Red Hat corp --- All Rights Reserved 8 * 9 * Journal commit routines for the generic filesystem journaling code; 10 * part of the ext2fs journaling system. 11 */ 12 13 #include <linux/time.h> 14 #include <linux/fs.h> 15 #include <linux/jbd2.h> 16 #include <linux/errno.h> 17 #include <linux/slab.h> 18 #include <linux/mm.h> 19 #include <linux/pagemap.h> 20 #include <linux/jiffies.h> 21 #include <linux/crc32.h> 22 #include <linux/writeback.h> 23 #include <linux/backing-dev.h> 24 #include <linux/bio.h> 25 #include <linux/blkdev.h> 26 #include <linux/bitops.h> 27 #include <trace/events/jbd2.h> 28 29 /* 30 * IO end handler for temporary buffer_heads handling writes to the journal. 31 */ 32 static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate) 33 { 34 struct buffer_head *orig_bh = bh->b_private; 35 36 BUFFER_TRACE(bh, ""); 37 if (uptodate) 38 set_buffer_uptodate(bh); 39 else 40 clear_buffer_uptodate(bh); 41 if (orig_bh) { 42 clear_bit_unlock(BH_Shadow, &orig_bh->b_state); 43 smp_mb__after_atomic(); 44 wake_up_bit(&orig_bh->b_state, BH_Shadow); 45 } 46 unlock_buffer(bh); 47 } 48 49 /* 50 * When an ext4 file is truncated, it is possible that some pages are not 51 * successfully freed, because they are attached to a committing transaction. 52 * After the transaction commits, these pages are left on the LRU, with no 53 * ->mapping, and with attached buffers. These pages are trivially reclaimable 54 * by the VM, but their apparent absence upsets the VM accounting, and it makes 55 * the numbers in /proc/meminfo look odd. 56 * 57 * So here, we have a buffer which has just come off the forget list. Look to 58 * see if we can strip all buffers from the backing page. 59 * 60 * Called under lock_journal(), and possibly under journal_datalist_lock. The 61 * caller provided us with a ref against the buffer, and we drop that here. 62 */ 63 static void release_buffer_page(struct buffer_head *bh) 64 { 65 struct page *page; 66 67 if (buffer_dirty(bh)) 68 goto nope; 69 if (atomic_read(&bh->b_count) != 1) 70 goto nope; 71 page = bh->b_page; 72 if (!page) 73 goto nope; 74 if (page->mapping) 75 goto nope; 76 77 /* OK, it's a truncated page */ 78 if (!trylock_page(page)) 79 goto nope; 80 81 get_page(page); 82 __brelse(bh); 83 try_to_free_buffers(page); 84 unlock_page(page); 85 put_page(page); 86 return; 87 88 nope: 89 __brelse(bh); 90 } 91 92 static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh) 93 { 94 struct commit_header *h; 95 __u32 csum; 96 97 if (!jbd2_journal_has_csum_v2or3(j)) 98 return; 99 100 h = (struct commit_header *)(bh->b_data); 101 h->h_chksum_type = 0; 102 h->h_chksum_size = 0; 103 h->h_chksum[0] = 0; 104 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize); 105 h->h_chksum[0] = cpu_to_be32(csum); 106 } 107 108 /* 109 * Done it all: now submit the commit record. We should have 110 * cleaned up our previous buffers by now, so if we are in abort 111 * mode we can now just skip the rest of the journal write 112 * entirely. 113 * 114 * Returns 1 if the journal needs to be aborted or 0 on success 115 */ 116 static int journal_submit_commit_record(journal_t *journal, 117 transaction_t *commit_transaction, 118 struct buffer_head **cbh, 119 __u32 crc32_sum) 120 { 121 struct commit_header *tmp; 122 struct buffer_head *bh; 123 int ret; 124 struct timespec64 now; 125 126 *cbh = NULL; 127 128 if (is_journal_aborted(journal)) 129 return 0; 130 131 bh = jbd2_journal_get_descriptor_buffer(commit_transaction, 132 JBD2_COMMIT_BLOCK); 133 if (!bh) 134 return 1; 135 136 tmp = (struct commit_header *)bh->b_data; 137 ktime_get_coarse_real_ts64(&now); 138 tmp->h_commit_sec = cpu_to_be64(now.tv_sec); 139 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec); 140 141 if (jbd2_has_feature_checksum(journal)) { 142 tmp->h_chksum_type = JBD2_CRC32_CHKSUM; 143 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE; 144 tmp->h_chksum[0] = cpu_to_be32(crc32_sum); 145 } 146 jbd2_commit_block_csum_set(journal, bh); 147 148 BUFFER_TRACE(bh, "submit commit block"); 149 lock_buffer(bh); 150 clear_buffer_dirty(bh); 151 set_buffer_uptodate(bh); 152 bh->b_end_io = journal_end_buffer_io_sync; 153 154 if (journal->j_flags & JBD2_BARRIER && 155 !jbd2_has_feature_async_commit(journal)) 156 ret = submit_bh(REQ_OP_WRITE, 157 REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh); 158 else 159 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh); 160 161 *cbh = bh; 162 return ret; 163 } 164 165 /* 166 * This function along with journal_submit_commit_record 167 * allows to write the commit record asynchronously. 168 */ 169 static int journal_wait_on_commit_record(journal_t *journal, 170 struct buffer_head *bh) 171 { 172 int ret = 0; 173 174 clear_buffer_dirty(bh); 175 wait_on_buffer(bh); 176 177 if (unlikely(!buffer_uptodate(bh))) 178 ret = -EIO; 179 put_bh(bh); /* One for getblk() */ 180 181 return ret; 182 } 183 184 /* 185 * write the filemap data using writepage() address_space_operations. 186 * We don't do block allocation here even for delalloc. We don't 187 * use writepages() because with delayed allocation we may be doing 188 * block allocation in writepages(). 189 */ 190 static int journal_submit_inode_data_buffers(struct address_space *mapping, 191 loff_t dirty_start, loff_t dirty_end) 192 { 193 int ret; 194 struct writeback_control wbc = { 195 .sync_mode = WB_SYNC_ALL, 196 .nr_to_write = mapping->nrpages * 2, 197 .range_start = dirty_start, 198 .range_end = dirty_end, 199 }; 200 201 ret = generic_writepages(mapping, &wbc); 202 return ret; 203 } 204 205 /* 206 * Submit all the data buffers of inode associated with the transaction to 207 * disk. 208 * 209 * We are in a committing transaction. Therefore no new inode can be added to 210 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently 211 * operate on from being released while we write out pages. 212 */ 213 static int journal_submit_data_buffers(journal_t *journal, 214 transaction_t *commit_transaction) 215 { 216 struct jbd2_inode *jinode; 217 int err, ret = 0; 218 struct address_space *mapping; 219 220 spin_lock(&journal->j_list_lock); 221 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 222 loff_t dirty_start = jinode->i_dirty_start; 223 loff_t dirty_end = jinode->i_dirty_end; 224 225 if (!(jinode->i_flags & JI_WRITE_DATA)) 226 continue; 227 mapping = jinode->i_vfs_inode->i_mapping; 228 jinode->i_flags |= JI_COMMIT_RUNNING; 229 spin_unlock(&journal->j_list_lock); 230 /* 231 * submit the inode data buffers. We use writepage 232 * instead of writepages. Because writepages can do 233 * block allocation with delalloc. We need to write 234 * only allocated blocks here. 235 */ 236 trace_jbd2_submit_inode_data(jinode->i_vfs_inode); 237 err = journal_submit_inode_data_buffers(mapping, dirty_start, 238 dirty_end); 239 if (!ret) 240 ret = err; 241 spin_lock(&journal->j_list_lock); 242 J_ASSERT(jinode->i_transaction == commit_transaction); 243 jinode->i_flags &= ~JI_COMMIT_RUNNING; 244 smp_mb(); 245 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 246 } 247 spin_unlock(&journal->j_list_lock); 248 return ret; 249 } 250 251 /* 252 * Wait for data submitted for writeout, refile inodes to proper 253 * transaction if needed. 254 * 255 */ 256 static int journal_finish_inode_data_buffers(journal_t *journal, 257 transaction_t *commit_transaction) 258 { 259 struct jbd2_inode *jinode, *next_i; 260 int err, ret = 0; 261 262 /* For locking, see the comment in journal_submit_data_buffers() */ 263 spin_lock(&journal->j_list_lock); 264 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 265 loff_t dirty_start = jinode->i_dirty_start; 266 loff_t dirty_end = jinode->i_dirty_end; 267 268 if (!(jinode->i_flags & JI_WAIT_DATA)) 269 continue; 270 jinode->i_flags |= JI_COMMIT_RUNNING; 271 spin_unlock(&journal->j_list_lock); 272 err = filemap_fdatawait_range_keep_errors( 273 jinode->i_vfs_inode->i_mapping, dirty_start, 274 dirty_end); 275 if (!ret) 276 ret = err; 277 spin_lock(&journal->j_list_lock); 278 jinode->i_flags &= ~JI_COMMIT_RUNNING; 279 smp_mb(); 280 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 281 } 282 283 /* Now refile inode to proper lists */ 284 list_for_each_entry_safe(jinode, next_i, 285 &commit_transaction->t_inode_list, i_list) { 286 list_del(&jinode->i_list); 287 if (jinode->i_next_transaction) { 288 jinode->i_transaction = jinode->i_next_transaction; 289 jinode->i_next_transaction = NULL; 290 list_add(&jinode->i_list, 291 &jinode->i_transaction->t_inode_list); 292 } else { 293 jinode->i_transaction = NULL; 294 jinode->i_dirty_start = 0; 295 jinode->i_dirty_end = 0; 296 } 297 } 298 spin_unlock(&journal->j_list_lock); 299 300 return ret; 301 } 302 303 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh) 304 { 305 struct page *page = bh->b_page; 306 char *addr; 307 __u32 checksum; 308 309 addr = kmap_atomic(page); 310 checksum = crc32_be(crc32_sum, 311 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size); 312 kunmap_atomic(addr); 313 314 return checksum; 315 } 316 317 static void write_tag_block(journal_t *j, journal_block_tag_t *tag, 318 unsigned long long block) 319 { 320 tag->t_blocknr = cpu_to_be32(block & (u32)~0); 321 if (jbd2_has_feature_64bit(j)) 322 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1); 323 } 324 325 static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag, 326 struct buffer_head *bh, __u32 sequence) 327 { 328 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag; 329 struct page *page = bh->b_page; 330 __u8 *addr; 331 __u32 csum32; 332 __be32 seq; 333 334 if (!jbd2_journal_has_csum_v2or3(j)) 335 return; 336 337 seq = cpu_to_be32(sequence); 338 addr = kmap_atomic(page); 339 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq)); 340 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data), 341 bh->b_size); 342 kunmap_atomic(addr); 343 344 if (jbd2_has_feature_csum3(j)) 345 tag3->t_checksum = cpu_to_be32(csum32); 346 else 347 tag->t_checksum = cpu_to_be16(csum32); 348 } 349 /* 350 * jbd2_journal_commit_transaction 351 * 352 * The primary function for committing a transaction to the log. This 353 * function is called by the journal thread to begin a complete commit. 354 */ 355 void jbd2_journal_commit_transaction(journal_t *journal) 356 { 357 struct transaction_stats_s stats; 358 transaction_t *commit_transaction; 359 struct journal_head *jh; 360 struct buffer_head *descriptor; 361 struct buffer_head **wbuf = journal->j_wbuf; 362 int bufs; 363 int flags; 364 int err; 365 unsigned long long blocknr; 366 ktime_t start_time; 367 u64 commit_time; 368 char *tagp = NULL; 369 journal_block_tag_t *tag = NULL; 370 int space_left = 0; 371 int first_tag = 0; 372 int tag_flag; 373 int i; 374 int tag_bytes = journal_tag_bytes(journal); 375 struct buffer_head *cbh = NULL; /* For transactional checksums */ 376 __u32 crc32_sum = ~0; 377 struct blk_plug plug; 378 /* Tail of the journal */ 379 unsigned long first_block; 380 tid_t first_tid; 381 int update_tail; 382 int csum_size = 0; 383 LIST_HEAD(io_bufs); 384 LIST_HEAD(log_bufs); 385 386 if (jbd2_journal_has_csum_v2or3(journal)) 387 csum_size = sizeof(struct jbd2_journal_block_tail); 388 389 /* 390 * First job: lock down the current transaction and wait for 391 * all outstanding updates to complete. 392 */ 393 394 /* Do we need to erase the effects of a prior jbd2_journal_flush? */ 395 if (journal->j_flags & JBD2_FLUSHED) { 396 jbd_debug(3, "super block updated\n"); 397 mutex_lock_io(&journal->j_checkpoint_mutex); 398 /* 399 * We hold j_checkpoint_mutex so tail cannot change under us. 400 * We don't need any special data guarantees for writing sb 401 * since journal is empty and it is ok for write to be 402 * flushed only with transaction commit. 403 */ 404 jbd2_journal_update_sb_log_tail(journal, 405 journal->j_tail_sequence, 406 journal->j_tail, 407 REQ_SYNC); 408 mutex_unlock(&journal->j_checkpoint_mutex); 409 } else { 410 jbd_debug(3, "superblock not updated\n"); 411 } 412 413 J_ASSERT(journal->j_running_transaction != NULL); 414 J_ASSERT(journal->j_committing_transaction == NULL); 415 416 commit_transaction = journal->j_running_transaction; 417 418 trace_jbd2_start_commit(journal, commit_transaction); 419 jbd_debug(1, "JBD2: starting commit of transaction %d\n", 420 commit_transaction->t_tid); 421 422 write_lock(&journal->j_state_lock); 423 J_ASSERT(commit_transaction->t_state == T_RUNNING); 424 commit_transaction->t_state = T_LOCKED; 425 426 trace_jbd2_commit_locking(journal, commit_transaction); 427 stats.run.rs_wait = commit_transaction->t_max_wait; 428 stats.run.rs_request_delay = 0; 429 stats.run.rs_locked = jiffies; 430 if (commit_transaction->t_requested) 431 stats.run.rs_request_delay = 432 jbd2_time_diff(commit_transaction->t_requested, 433 stats.run.rs_locked); 434 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start, 435 stats.run.rs_locked); 436 437 spin_lock(&commit_transaction->t_handle_lock); 438 while (atomic_read(&commit_transaction->t_updates)) { 439 DEFINE_WAIT(wait); 440 441 prepare_to_wait(&journal->j_wait_updates, &wait, 442 TASK_UNINTERRUPTIBLE); 443 if (atomic_read(&commit_transaction->t_updates)) { 444 spin_unlock(&commit_transaction->t_handle_lock); 445 write_unlock(&journal->j_state_lock); 446 schedule(); 447 write_lock(&journal->j_state_lock); 448 spin_lock(&commit_transaction->t_handle_lock); 449 } 450 finish_wait(&journal->j_wait_updates, &wait); 451 } 452 spin_unlock(&commit_transaction->t_handle_lock); 453 commit_transaction->t_state = T_SWITCH; 454 write_unlock(&journal->j_state_lock); 455 456 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <= 457 journal->j_max_transaction_buffers); 458 459 /* 460 * First thing we are allowed to do is to discard any remaining 461 * BJ_Reserved buffers. Note, it is _not_ permissible to assume 462 * that there are no such buffers: if a large filesystem 463 * operation like a truncate needs to split itself over multiple 464 * transactions, then it may try to do a jbd2_journal_restart() while 465 * there are still BJ_Reserved buffers outstanding. These must 466 * be released cleanly from the current transaction. 467 * 468 * In this case, the filesystem must still reserve write access 469 * again before modifying the buffer in the new transaction, but 470 * we do not require it to remember exactly which old buffers it 471 * has reserved. This is consistent with the existing behaviour 472 * that multiple jbd2_journal_get_write_access() calls to the same 473 * buffer are perfectly permissible. 474 */ 475 while (commit_transaction->t_reserved_list) { 476 jh = commit_transaction->t_reserved_list; 477 JBUFFER_TRACE(jh, "reserved, unused: refile"); 478 /* 479 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may 480 * leave undo-committed data. 481 */ 482 if (jh->b_committed_data) { 483 struct buffer_head *bh = jh2bh(jh); 484 485 jbd_lock_bh_state(bh); 486 jbd2_free(jh->b_committed_data, bh->b_size); 487 jh->b_committed_data = NULL; 488 jbd_unlock_bh_state(bh); 489 } 490 jbd2_journal_refile_buffer(journal, jh); 491 } 492 493 /* 494 * Now try to drop any written-back buffers from the journal's 495 * checkpoint lists. We do this *before* commit because it potentially 496 * frees some memory 497 */ 498 spin_lock(&journal->j_list_lock); 499 __jbd2_journal_clean_checkpoint_list(journal, false); 500 spin_unlock(&journal->j_list_lock); 501 502 jbd_debug(3, "JBD2: commit phase 1\n"); 503 504 /* 505 * Clear revoked flag to reflect there is no revoked buffers 506 * in the next transaction which is going to be started. 507 */ 508 jbd2_clear_buffer_revoked_flags(journal); 509 510 /* 511 * Switch to a new revoke table. 512 */ 513 jbd2_journal_switch_revoke_table(journal); 514 515 /* 516 * Reserved credits cannot be claimed anymore, free them 517 */ 518 atomic_sub(atomic_read(&journal->j_reserved_credits), 519 &commit_transaction->t_outstanding_credits); 520 521 write_lock(&journal->j_state_lock); 522 trace_jbd2_commit_flushing(journal, commit_transaction); 523 stats.run.rs_flushing = jiffies; 524 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked, 525 stats.run.rs_flushing); 526 527 commit_transaction->t_state = T_FLUSH; 528 journal->j_committing_transaction = commit_transaction; 529 journal->j_running_transaction = NULL; 530 start_time = ktime_get(); 531 commit_transaction->t_log_start = journal->j_head; 532 wake_up(&journal->j_wait_transaction_locked); 533 write_unlock(&journal->j_state_lock); 534 535 jbd_debug(3, "JBD2: commit phase 2a\n"); 536 537 /* 538 * Now start flushing things to disk, in the order they appear 539 * on the transaction lists. Data blocks go first. 540 */ 541 err = journal_submit_data_buffers(journal, commit_transaction); 542 if (err) 543 jbd2_journal_abort(journal, err); 544 545 blk_start_plug(&plug); 546 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs); 547 548 jbd_debug(3, "JBD2: commit phase 2b\n"); 549 550 /* 551 * Way to go: we have now written out all of the data for a 552 * transaction! Now comes the tricky part: we need to write out 553 * metadata. Loop over the transaction's entire buffer list: 554 */ 555 write_lock(&journal->j_state_lock); 556 commit_transaction->t_state = T_COMMIT; 557 write_unlock(&journal->j_state_lock); 558 559 trace_jbd2_commit_logging(journal, commit_transaction); 560 stats.run.rs_logging = jiffies; 561 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing, 562 stats.run.rs_logging); 563 stats.run.rs_blocks = 564 atomic_read(&commit_transaction->t_outstanding_credits); 565 stats.run.rs_blocks_logged = 0; 566 567 J_ASSERT(commit_transaction->t_nr_buffers <= 568 atomic_read(&commit_transaction->t_outstanding_credits)); 569 570 err = 0; 571 bufs = 0; 572 descriptor = NULL; 573 while (commit_transaction->t_buffers) { 574 575 /* Find the next buffer to be journaled... */ 576 577 jh = commit_transaction->t_buffers; 578 579 /* If we're in abort mode, we just un-journal the buffer and 580 release it. */ 581 582 if (is_journal_aborted(journal)) { 583 clear_buffer_jbddirty(jh2bh(jh)); 584 JBUFFER_TRACE(jh, "journal is aborting: refile"); 585 jbd2_buffer_abort_trigger(jh, 586 jh->b_frozen_data ? 587 jh->b_frozen_triggers : 588 jh->b_triggers); 589 jbd2_journal_refile_buffer(journal, jh); 590 /* If that was the last one, we need to clean up 591 * any descriptor buffers which may have been 592 * already allocated, even if we are now 593 * aborting. */ 594 if (!commit_transaction->t_buffers) 595 goto start_journal_io; 596 continue; 597 } 598 599 /* Make sure we have a descriptor block in which to 600 record the metadata buffer. */ 601 602 if (!descriptor) { 603 J_ASSERT (bufs == 0); 604 605 jbd_debug(4, "JBD2: get descriptor\n"); 606 607 descriptor = jbd2_journal_get_descriptor_buffer( 608 commit_transaction, 609 JBD2_DESCRIPTOR_BLOCK); 610 if (!descriptor) { 611 jbd2_journal_abort(journal, -EIO); 612 continue; 613 } 614 615 jbd_debug(4, "JBD2: got buffer %llu (%p)\n", 616 (unsigned long long)descriptor->b_blocknr, 617 descriptor->b_data); 618 tagp = &descriptor->b_data[sizeof(journal_header_t)]; 619 space_left = descriptor->b_size - 620 sizeof(journal_header_t); 621 first_tag = 1; 622 set_buffer_jwrite(descriptor); 623 set_buffer_dirty(descriptor); 624 wbuf[bufs++] = descriptor; 625 626 /* Record it so that we can wait for IO 627 completion later */ 628 BUFFER_TRACE(descriptor, "ph3: file as descriptor"); 629 jbd2_file_log_bh(&log_bufs, descriptor); 630 } 631 632 /* Where is the buffer to be written? */ 633 634 err = jbd2_journal_next_log_block(journal, &blocknr); 635 /* If the block mapping failed, just abandon the buffer 636 and repeat this loop: we'll fall into the 637 refile-on-abort condition above. */ 638 if (err) { 639 jbd2_journal_abort(journal, err); 640 continue; 641 } 642 643 /* 644 * start_this_handle() uses t_outstanding_credits to determine 645 * the free space in the log, but this counter is changed 646 * by jbd2_journal_next_log_block() also. 647 */ 648 atomic_dec(&commit_transaction->t_outstanding_credits); 649 650 /* Bump b_count to prevent truncate from stumbling over 651 the shadowed buffer! @@@ This can go if we ever get 652 rid of the shadow pairing of buffers. */ 653 atomic_inc(&jh2bh(jh)->b_count); 654 655 /* 656 * Make a temporary IO buffer with which to write it out 657 * (this will requeue the metadata buffer to BJ_Shadow). 658 */ 659 set_bit(BH_JWrite, &jh2bh(jh)->b_state); 660 JBUFFER_TRACE(jh, "ph3: write metadata"); 661 flags = jbd2_journal_write_metadata_buffer(commit_transaction, 662 jh, &wbuf[bufs], blocknr); 663 if (flags < 0) { 664 jbd2_journal_abort(journal, flags); 665 continue; 666 } 667 jbd2_file_log_bh(&io_bufs, wbuf[bufs]); 668 669 /* Record the new block's tag in the current descriptor 670 buffer */ 671 672 tag_flag = 0; 673 if (flags & 1) 674 tag_flag |= JBD2_FLAG_ESCAPE; 675 if (!first_tag) 676 tag_flag |= JBD2_FLAG_SAME_UUID; 677 678 tag = (journal_block_tag_t *) tagp; 679 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr); 680 tag->t_flags = cpu_to_be16(tag_flag); 681 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs], 682 commit_transaction->t_tid); 683 tagp += tag_bytes; 684 space_left -= tag_bytes; 685 bufs++; 686 687 if (first_tag) { 688 memcpy (tagp, journal->j_uuid, 16); 689 tagp += 16; 690 space_left -= 16; 691 first_tag = 0; 692 } 693 694 /* If there's no more to do, or if the descriptor is full, 695 let the IO rip! */ 696 697 if (bufs == journal->j_wbufsize || 698 commit_transaction->t_buffers == NULL || 699 space_left < tag_bytes + 16 + csum_size) { 700 701 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs); 702 703 /* Write an end-of-descriptor marker before 704 submitting the IOs. "tag" still points to 705 the last tag we set up. */ 706 707 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG); 708 start_journal_io: 709 if (descriptor) 710 jbd2_descriptor_block_csum_set(journal, 711 descriptor); 712 713 for (i = 0; i < bufs; i++) { 714 struct buffer_head *bh = wbuf[i]; 715 /* 716 * Compute checksum. 717 */ 718 if (jbd2_has_feature_checksum(journal)) { 719 crc32_sum = 720 jbd2_checksum_data(crc32_sum, bh); 721 } 722 723 lock_buffer(bh); 724 clear_buffer_dirty(bh); 725 set_buffer_uptodate(bh); 726 bh->b_end_io = journal_end_buffer_io_sync; 727 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh); 728 } 729 cond_resched(); 730 stats.run.rs_blocks_logged += bufs; 731 732 /* Force a new descriptor to be generated next 733 time round the loop. */ 734 descriptor = NULL; 735 bufs = 0; 736 } 737 } 738 739 err = journal_finish_inode_data_buffers(journal, commit_transaction); 740 if (err) { 741 printk(KERN_WARNING 742 "JBD2: Detected IO errors while flushing file data " 743 "on %s\n", journal->j_devname); 744 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR) 745 jbd2_journal_abort(journal, err); 746 err = 0; 747 } 748 749 /* 750 * Get current oldest transaction in the log before we issue flush 751 * to the filesystem device. After the flush we can be sure that 752 * blocks of all older transactions are checkpointed to persistent 753 * storage and we will be safe to update journal start in the 754 * superblock with the numbers we get here. 755 */ 756 update_tail = 757 jbd2_journal_get_log_tail(journal, &first_tid, &first_block); 758 759 write_lock(&journal->j_state_lock); 760 if (update_tail) { 761 long freed = first_block - journal->j_tail; 762 763 if (first_block < journal->j_tail) 764 freed += journal->j_last - journal->j_first; 765 /* Update tail only if we free significant amount of space */ 766 if (freed < journal->j_maxlen / 4) 767 update_tail = 0; 768 } 769 J_ASSERT(commit_transaction->t_state == T_COMMIT); 770 commit_transaction->t_state = T_COMMIT_DFLUSH; 771 write_unlock(&journal->j_state_lock); 772 773 /* 774 * If the journal is not located on the file system device, 775 * then we must flush the file system device before we issue 776 * the commit record 777 */ 778 if (commit_transaction->t_need_data_flush && 779 (journal->j_fs_dev != journal->j_dev) && 780 (journal->j_flags & JBD2_BARRIER)) 781 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL); 782 783 /* Done it all: now write the commit record asynchronously. */ 784 if (jbd2_has_feature_async_commit(journal)) { 785 err = journal_submit_commit_record(journal, commit_transaction, 786 &cbh, crc32_sum); 787 if (err) 788 __jbd2_journal_abort_hard(journal); 789 } 790 791 blk_finish_plug(&plug); 792 793 /* Lo and behold: we have just managed to send a transaction to 794 the log. Before we can commit it, wait for the IO so far to 795 complete. Control buffers being written are on the 796 transaction's t_log_list queue, and metadata buffers are on 797 the io_bufs list. 798 799 Wait for the buffers in reverse order. That way we are 800 less likely to be woken up until all IOs have completed, and 801 so we incur less scheduling load. 802 */ 803 804 jbd_debug(3, "JBD2: commit phase 3\n"); 805 806 while (!list_empty(&io_bufs)) { 807 struct buffer_head *bh = list_entry(io_bufs.prev, 808 struct buffer_head, 809 b_assoc_buffers); 810 811 wait_on_buffer(bh); 812 cond_resched(); 813 814 if (unlikely(!buffer_uptodate(bh))) 815 err = -EIO; 816 jbd2_unfile_log_bh(bh); 817 818 /* 819 * The list contains temporary buffer heads created by 820 * jbd2_journal_write_metadata_buffer(). 821 */ 822 BUFFER_TRACE(bh, "dumping temporary bh"); 823 __brelse(bh); 824 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); 825 free_buffer_head(bh); 826 827 /* We also have to refile the corresponding shadowed buffer */ 828 jh = commit_transaction->t_shadow_list->b_tprev; 829 bh = jh2bh(jh); 830 clear_buffer_jwrite(bh); 831 J_ASSERT_BH(bh, buffer_jbddirty(bh)); 832 J_ASSERT_BH(bh, !buffer_shadow(bh)); 833 834 /* The metadata is now released for reuse, but we need 835 to remember it against this transaction so that when 836 we finally commit, we can do any checkpointing 837 required. */ 838 JBUFFER_TRACE(jh, "file as BJ_Forget"); 839 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget); 840 JBUFFER_TRACE(jh, "brelse shadowed buffer"); 841 __brelse(bh); 842 } 843 844 J_ASSERT (commit_transaction->t_shadow_list == NULL); 845 846 jbd_debug(3, "JBD2: commit phase 4\n"); 847 848 /* Here we wait for the revoke record and descriptor record buffers */ 849 while (!list_empty(&log_bufs)) { 850 struct buffer_head *bh; 851 852 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers); 853 wait_on_buffer(bh); 854 cond_resched(); 855 856 if (unlikely(!buffer_uptodate(bh))) 857 err = -EIO; 858 859 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); 860 clear_buffer_jwrite(bh); 861 jbd2_unfile_log_bh(bh); 862 __brelse(bh); /* One for getblk */ 863 /* AKPM: bforget here */ 864 } 865 866 if (err) 867 jbd2_journal_abort(journal, err); 868 869 jbd_debug(3, "JBD2: commit phase 5\n"); 870 write_lock(&journal->j_state_lock); 871 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH); 872 commit_transaction->t_state = T_COMMIT_JFLUSH; 873 write_unlock(&journal->j_state_lock); 874 875 if (!jbd2_has_feature_async_commit(journal)) { 876 err = journal_submit_commit_record(journal, commit_transaction, 877 &cbh, crc32_sum); 878 if (err) 879 __jbd2_journal_abort_hard(journal); 880 } 881 if (cbh) 882 err = journal_wait_on_commit_record(journal, cbh); 883 if (jbd2_has_feature_async_commit(journal) && 884 journal->j_flags & JBD2_BARRIER) { 885 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL); 886 } 887 888 if (err) 889 jbd2_journal_abort(journal, err); 890 891 /* 892 * Now disk caches for filesystem device are flushed so we are safe to 893 * erase checkpointed transactions from the log by updating journal 894 * superblock. 895 */ 896 if (update_tail) 897 jbd2_update_log_tail(journal, first_tid, first_block); 898 899 /* End of a transaction! Finally, we can do checkpoint 900 processing: any buffers committed as a result of this 901 transaction can be removed from any checkpoint list it was on 902 before. */ 903 904 jbd_debug(3, "JBD2: commit phase 6\n"); 905 906 J_ASSERT(list_empty(&commit_transaction->t_inode_list)); 907 J_ASSERT(commit_transaction->t_buffers == NULL); 908 J_ASSERT(commit_transaction->t_checkpoint_list == NULL); 909 J_ASSERT(commit_transaction->t_shadow_list == NULL); 910 911 restart_loop: 912 /* 913 * As there are other places (journal_unmap_buffer()) adding buffers 914 * to this list we have to be careful and hold the j_list_lock. 915 */ 916 spin_lock(&journal->j_list_lock); 917 while (commit_transaction->t_forget) { 918 transaction_t *cp_transaction; 919 struct buffer_head *bh; 920 int try_to_free = 0; 921 922 jh = commit_transaction->t_forget; 923 spin_unlock(&journal->j_list_lock); 924 bh = jh2bh(jh); 925 /* 926 * Get a reference so that bh cannot be freed before we are 927 * done with it. 928 */ 929 get_bh(bh); 930 jbd_lock_bh_state(bh); 931 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction); 932 933 /* 934 * If there is undo-protected committed data against 935 * this buffer, then we can remove it now. If it is a 936 * buffer needing such protection, the old frozen_data 937 * field now points to a committed version of the 938 * buffer, so rotate that field to the new committed 939 * data. 940 * 941 * Otherwise, we can just throw away the frozen data now. 942 * 943 * We also know that the frozen data has already fired 944 * its triggers if they exist, so we can clear that too. 945 */ 946 if (jh->b_committed_data) { 947 jbd2_free(jh->b_committed_data, bh->b_size); 948 jh->b_committed_data = NULL; 949 if (jh->b_frozen_data) { 950 jh->b_committed_data = jh->b_frozen_data; 951 jh->b_frozen_data = NULL; 952 jh->b_frozen_triggers = NULL; 953 } 954 } else if (jh->b_frozen_data) { 955 jbd2_free(jh->b_frozen_data, bh->b_size); 956 jh->b_frozen_data = NULL; 957 jh->b_frozen_triggers = NULL; 958 } 959 960 spin_lock(&journal->j_list_lock); 961 cp_transaction = jh->b_cp_transaction; 962 if (cp_transaction) { 963 JBUFFER_TRACE(jh, "remove from old cp transaction"); 964 cp_transaction->t_chp_stats.cs_dropped++; 965 __jbd2_journal_remove_checkpoint(jh); 966 } 967 968 /* Only re-checkpoint the buffer_head if it is marked 969 * dirty. If the buffer was added to the BJ_Forget list 970 * by jbd2_journal_forget, it may no longer be dirty and 971 * there's no point in keeping a checkpoint record for 972 * it. */ 973 974 /* 975 * A buffer which has been freed while still being journaled by 976 * a previous transaction. 977 */ 978 if (buffer_freed(bh)) { 979 /* 980 * If the running transaction is the one containing 981 * "add to orphan" operation (b_next_transaction != 982 * NULL), we have to wait for that transaction to 983 * commit before we can really get rid of the buffer. 984 * So just clear b_modified to not confuse transaction 985 * credit accounting and refile the buffer to 986 * BJ_Forget of the running transaction. If the just 987 * committed transaction contains "add to orphan" 988 * operation, we can completely invalidate the buffer 989 * now. We are rather through in that since the 990 * buffer may be still accessible when blocksize < 991 * pagesize and it is attached to the last partial 992 * page. 993 */ 994 jh->b_modified = 0; 995 if (!jh->b_next_transaction) { 996 clear_buffer_freed(bh); 997 clear_buffer_jbddirty(bh); 998 clear_buffer_mapped(bh); 999 clear_buffer_new(bh); 1000 clear_buffer_req(bh); 1001 bh->b_bdev = NULL; 1002 } 1003 } 1004 1005 if (buffer_jbddirty(bh)) { 1006 JBUFFER_TRACE(jh, "add to new checkpointing trans"); 1007 __jbd2_journal_insert_checkpoint(jh, commit_transaction); 1008 if (is_journal_aborted(journal)) 1009 clear_buffer_jbddirty(bh); 1010 } else { 1011 J_ASSERT_BH(bh, !buffer_dirty(bh)); 1012 /* 1013 * The buffer on BJ_Forget list and not jbddirty means 1014 * it has been freed by this transaction and hence it 1015 * could not have been reallocated until this 1016 * transaction has committed. *BUT* it could be 1017 * reallocated once we have written all the data to 1018 * disk and before we process the buffer on BJ_Forget 1019 * list. 1020 */ 1021 if (!jh->b_next_transaction) 1022 try_to_free = 1; 1023 } 1024 JBUFFER_TRACE(jh, "refile or unfile buffer"); 1025 __jbd2_journal_refile_buffer(jh); 1026 jbd_unlock_bh_state(bh); 1027 if (try_to_free) 1028 release_buffer_page(bh); /* Drops bh reference */ 1029 else 1030 __brelse(bh); 1031 cond_resched_lock(&journal->j_list_lock); 1032 } 1033 spin_unlock(&journal->j_list_lock); 1034 /* 1035 * This is a bit sleazy. We use j_list_lock to protect transition 1036 * of a transaction into T_FINISHED state and calling 1037 * __jbd2_journal_drop_transaction(). Otherwise we could race with 1038 * other checkpointing code processing the transaction... 1039 */ 1040 write_lock(&journal->j_state_lock); 1041 spin_lock(&journal->j_list_lock); 1042 /* 1043 * Now recheck if some buffers did not get attached to the transaction 1044 * while the lock was dropped... 1045 */ 1046 if (commit_transaction->t_forget) { 1047 spin_unlock(&journal->j_list_lock); 1048 write_unlock(&journal->j_state_lock); 1049 goto restart_loop; 1050 } 1051 1052 /* Add the transaction to the checkpoint list 1053 * __journal_remove_checkpoint() can not destroy transaction 1054 * under us because it is not marked as T_FINISHED yet */ 1055 if (journal->j_checkpoint_transactions == NULL) { 1056 journal->j_checkpoint_transactions = commit_transaction; 1057 commit_transaction->t_cpnext = commit_transaction; 1058 commit_transaction->t_cpprev = commit_transaction; 1059 } else { 1060 commit_transaction->t_cpnext = 1061 journal->j_checkpoint_transactions; 1062 commit_transaction->t_cpprev = 1063 commit_transaction->t_cpnext->t_cpprev; 1064 commit_transaction->t_cpnext->t_cpprev = 1065 commit_transaction; 1066 commit_transaction->t_cpprev->t_cpnext = 1067 commit_transaction; 1068 } 1069 spin_unlock(&journal->j_list_lock); 1070 1071 /* Done with this transaction! */ 1072 1073 jbd_debug(3, "JBD2: commit phase 7\n"); 1074 1075 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH); 1076 1077 commit_transaction->t_start = jiffies; 1078 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging, 1079 commit_transaction->t_start); 1080 1081 /* 1082 * File the transaction statistics 1083 */ 1084 stats.ts_tid = commit_transaction->t_tid; 1085 stats.run.rs_handle_count = 1086 atomic_read(&commit_transaction->t_handle_count); 1087 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev, 1088 commit_transaction->t_tid, &stats.run); 1089 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0; 1090 1091 commit_transaction->t_state = T_COMMIT_CALLBACK; 1092 J_ASSERT(commit_transaction == journal->j_committing_transaction); 1093 journal->j_commit_sequence = commit_transaction->t_tid; 1094 journal->j_committing_transaction = NULL; 1095 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); 1096 1097 /* 1098 * weight the commit time higher than the average time so we don't 1099 * react too strongly to vast changes in the commit time 1100 */ 1101 if (likely(journal->j_average_commit_time)) 1102 journal->j_average_commit_time = (commit_time + 1103 journal->j_average_commit_time*3) / 4; 1104 else 1105 journal->j_average_commit_time = commit_time; 1106 1107 write_unlock(&journal->j_state_lock); 1108 1109 if (journal->j_commit_callback) 1110 journal->j_commit_callback(journal, commit_transaction); 1111 1112 trace_jbd2_end_commit(journal, commit_transaction); 1113 jbd_debug(1, "JBD2: commit %d complete, head %d\n", 1114 journal->j_commit_sequence, journal->j_tail_sequence); 1115 1116 write_lock(&journal->j_state_lock); 1117 spin_lock(&journal->j_list_lock); 1118 commit_transaction->t_state = T_FINISHED; 1119 /* Check if the transaction can be dropped now that we are finished */ 1120 if (commit_transaction->t_checkpoint_list == NULL && 1121 commit_transaction->t_checkpoint_io_list == NULL) { 1122 __jbd2_journal_drop_transaction(journal, commit_transaction); 1123 jbd2_journal_free_transaction(commit_transaction); 1124 } 1125 spin_unlock(&journal->j_list_lock); 1126 write_unlock(&journal->j_state_lock); 1127 wake_up(&journal->j_wait_done_commit); 1128 1129 /* 1130 * Calculate overall stats 1131 */ 1132 spin_lock(&journal->j_history_lock); 1133 journal->j_stats.ts_tid++; 1134 journal->j_stats.ts_requested += stats.ts_requested; 1135 journal->j_stats.run.rs_wait += stats.run.rs_wait; 1136 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay; 1137 journal->j_stats.run.rs_running += stats.run.rs_running; 1138 journal->j_stats.run.rs_locked += stats.run.rs_locked; 1139 journal->j_stats.run.rs_flushing += stats.run.rs_flushing; 1140 journal->j_stats.run.rs_logging += stats.run.rs_logging; 1141 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count; 1142 journal->j_stats.run.rs_blocks += stats.run.rs_blocks; 1143 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged; 1144 spin_unlock(&journal->j_history_lock); 1145 } 1146