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 folio *folio; 66 67 if (buffer_dirty(bh)) 68 goto nope; 69 if (atomic_read(&bh->b_count) != 1) 70 goto nope; 71 folio = bh->b_folio; 72 if (folio->mapping) 73 goto nope; 74 75 /* OK, it's a truncated page */ 76 if (!folio_trylock(folio)) 77 goto nope; 78 79 folio_get(folio); 80 __brelse(bh); 81 try_to_free_buffers(folio); 82 folio_unlock(folio); 83 folio_put(folio); 84 return; 85 86 nope: 87 __brelse(bh); 88 } 89 90 static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh) 91 { 92 struct commit_header *h; 93 __u32 csum; 94 95 if (!jbd2_journal_has_csum_v2or3(j)) 96 return; 97 98 h = (struct commit_header *)(bh->b_data); 99 h->h_chksum_type = 0; 100 h->h_chksum_size = 0; 101 h->h_chksum[0] = 0; 102 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize); 103 h->h_chksum[0] = cpu_to_be32(csum); 104 } 105 106 /* 107 * Done it all: now submit the commit record. We should have 108 * cleaned up our previous buffers by now, so if we are in abort 109 * mode we can now just skip the rest of the journal write 110 * entirely. 111 * 112 * Returns 1 if the journal needs to be aborted or 0 on success 113 */ 114 static int journal_submit_commit_record(journal_t *journal, 115 transaction_t *commit_transaction, 116 struct buffer_head **cbh, 117 __u32 crc32_sum) 118 { 119 struct commit_header *tmp; 120 struct buffer_head *bh; 121 struct timespec64 now; 122 blk_opf_t write_flags = REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS; 123 124 *cbh = NULL; 125 126 if (is_journal_aborted(journal)) 127 return 0; 128 129 bh = jbd2_journal_get_descriptor_buffer(commit_transaction, 130 JBD2_COMMIT_BLOCK); 131 if (!bh) 132 return 1; 133 134 tmp = (struct commit_header *)bh->b_data; 135 ktime_get_coarse_real_ts64(&now); 136 tmp->h_commit_sec = cpu_to_be64(now.tv_sec); 137 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec); 138 139 if (jbd2_has_feature_checksum(journal)) { 140 tmp->h_chksum_type = JBD2_CRC32_CHKSUM; 141 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE; 142 tmp->h_chksum[0] = cpu_to_be32(crc32_sum); 143 } 144 jbd2_commit_block_csum_set(journal, bh); 145 146 BUFFER_TRACE(bh, "submit commit block"); 147 lock_buffer(bh); 148 clear_buffer_dirty(bh); 149 set_buffer_uptodate(bh); 150 bh->b_end_io = journal_end_buffer_io_sync; 151 152 if (journal->j_flags & JBD2_BARRIER && 153 !jbd2_has_feature_async_commit(journal)) 154 write_flags |= REQ_PREFLUSH | REQ_FUA; 155 156 submit_bh(write_flags, bh); 157 *cbh = bh; 158 return 0; 159 } 160 161 /* 162 * This function along with journal_submit_commit_record 163 * allows to write the commit record asynchronously. 164 */ 165 static int journal_wait_on_commit_record(journal_t *journal, 166 struct buffer_head *bh) 167 { 168 int ret = 0; 169 170 clear_buffer_dirty(bh); 171 wait_on_buffer(bh); 172 173 if (unlikely(!buffer_uptodate(bh))) 174 ret = -EIO; 175 put_bh(bh); /* One for getblk() */ 176 177 return ret; 178 } 179 180 /* Send all the data buffers related to an inode */ 181 int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode) 182 { 183 if (!jinode || !(jinode->i_flags & JI_WRITE_DATA)) 184 return 0; 185 186 trace_jbd2_submit_inode_data(jinode->i_vfs_inode); 187 return journal->j_submit_inode_data_buffers(jinode); 188 189 } 190 EXPORT_SYMBOL(jbd2_submit_inode_data); 191 192 int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode) 193 { 194 if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) || 195 !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping) 196 return 0; 197 return filemap_fdatawait_range_keep_errors( 198 jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start, 199 jinode->i_dirty_end); 200 } 201 EXPORT_SYMBOL(jbd2_wait_inode_data); 202 203 /* 204 * Submit all the data buffers of inode associated with the transaction to 205 * disk. 206 * 207 * We are in a committing transaction. Therefore no new inode can be added to 208 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently 209 * operate on from being released while we write out pages. 210 */ 211 static int journal_submit_data_buffers(journal_t *journal, 212 transaction_t *commit_transaction) 213 { 214 struct jbd2_inode *jinode; 215 int err, ret = 0; 216 217 spin_lock(&journal->j_list_lock); 218 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 219 if (!(jinode->i_flags & JI_WRITE_DATA)) 220 continue; 221 jinode->i_flags |= JI_COMMIT_RUNNING; 222 spin_unlock(&journal->j_list_lock); 223 /* submit the inode data buffers. */ 224 trace_jbd2_submit_inode_data(jinode->i_vfs_inode); 225 if (journal->j_submit_inode_data_buffers) { 226 err = journal->j_submit_inode_data_buffers(jinode); 227 if (!ret) 228 ret = err; 229 } 230 spin_lock(&journal->j_list_lock); 231 J_ASSERT(jinode->i_transaction == commit_transaction); 232 jinode->i_flags &= ~JI_COMMIT_RUNNING; 233 smp_mb(); 234 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 235 } 236 spin_unlock(&journal->j_list_lock); 237 return ret; 238 } 239 240 int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode) 241 { 242 struct address_space *mapping = jinode->i_vfs_inode->i_mapping; 243 244 return filemap_fdatawait_range_keep_errors(mapping, 245 jinode->i_dirty_start, 246 jinode->i_dirty_end); 247 } 248 249 /* 250 * Wait for data submitted for writeout, refile inodes to proper 251 * transaction if needed. 252 * 253 */ 254 static int journal_finish_inode_data_buffers(journal_t *journal, 255 transaction_t *commit_transaction) 256 { 257 struct jbd2_inode *jinode, *next_i; 258 int err, ret = 0; 259 260 /* For locking, see the comment in journal_submit_data_buffers() */ 261 spin_lock(&journal->j_list_lock); 262 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 263 if (!(jinode->i_flags & JI_WAIT_DATA)) 264 continue; 265 jinode->i_flags |= JI_COMMIT_RUNNING; 266 spin_unlock(&journal->j_list_lock); 267 /* wait for the inode data buffers writeout. */ 268 if (journal->j_finish_inode_data_buffers) { 269 err = journal->j_finish_inode_data_buffers(jinode); 270 if (!ret) 271 ret = err; 272 } 273 cond_resched(); 274 spin_lock(&journal->j_list_lock); 275 jinode->i_flags &= ~JI_COMMIT_RUNNING; 276 smp_mb(); 277 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 278 } 279 280 /* Now refile inode to proper lists */ 281 list_for_each_entry_safe(jinode, next_i, 282 &commit_transaction->t_inode_list, i_list) { 283 list_del(&jinode->i_list); 284 if (jinode->i_next_transaction) { 285 jinode->i_transaction = jinode->i_next_transaction; 286 jinode->i_next_transaction = NULL; 287 list_add(&jinode->i_list, 288 &jinode->i_transaction->t_inode_list); 289 } else { 290 jinode->i_transaction = NULL; 291 jinode->i_dirty_start = 0; 292 jinode->i_dirty_end = 0; 293 } 294 } 295 spin_unlock(&journal->j_list_lock); 296 297 return ret; 298 } 299 300 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh) 301 { 302 char *addr; 303 __u32 checksum; 304 305 addr = kmap_local_folio(bh->b_folio, bh_offset(bh)); 306 checksum = crc32_be(crc32_sum, addr, bh->b_size); 307 kunmap_local(addr); 308 309 return checksum; 310 } 311 312 static void write_tag_block(journal_t *j, journal_block_tag_t *tag, 313 unsigned long long block) 314 { 315 tag->t_blocknr = cpu_to_be32(block & (u32)~0); 316 if (jbd2_has_feature_64bit(j)) 317 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1); 318 } 319 320 static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag, 321 struct buffer_head *bh, __u32 sequence) 322 { 323 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag; 324 __u8 *addr; 325 __u32 csum32; 326 __be32 seq; 327 328 if (!jbd2_journal_has_csum_v2or3(j)) 329 return; 330 331 seq = cpu_to_be32(sequence); 332 addr = kmap_local_folio(bh->b_folio, bh_offset(bh)); 333 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq)); 334 csum32 = jbd2_chksum(j, csum32, addr, bh->b_size); 335 kunmap_local(addr); 336 337 if (jbd2_has_feature_csum3(j)) 338 tag3->t_checksum = cpu_to_be32(csum32); 339 else 340 tag->t_checksum = cpu_to_be16(csum32); 341 } 342 /* 343 * jbd2_journal_commit_transaction 344 * 345 * The primary function for committing a transaction to the log. This 346 * function is called by the journal thread to begin a complete commit. 347 */ 348 void jbd2_journal_commit_transaction(journal_t *journal) 349 { 350 struct transaction_stats_s stats; 351 transaction_t *commit_transaction; 352 struct journal_head *jh; 353 struct buffer_head *descriptor; 354 struct buffer_head **wbuf = journal->j_wbuf; 355 int bufs; 356 int flags; 357 int err; 358 unsigned long long blocknr; 359 ktime_t start_time; 360 u64 commit_time; 361 char *tagp = NULL; 362 journal_block_tag_t *tag = NULL; 363 int space_left = 0; 364 int first_tag = 0; 365 int tag_flag; 366 int i; 367 int tag_bytes = journal_tag_bytes(journal); 368 struct buffer_head *cbh = NULL; /* For transactional checksums */ 369 __u32 crc32_sum = ~0; 370 struct blk_plug plug; 371 /* Tail of the journal */ 372 unsigned long first_block; 373 tid_t first_tid; 374 int update_tail; 375 int csum_size = 0; 376 LIST_HEAD(io_bufs); 377 LIST_HEAD(log_bufs); 378 379 if (jbd2_journal_has_csum_v2or3(journal)) 380 csum_size = sizeof(struct jbd2_journal_block_tail); 381 382 /* 383 * First job: lock down the current transaction and wait for 384 * all outstanding updates to complete. 385 */ 386 387 /* Do we need to erase the effects of a prior jbd2_journal_flush? */ 388 if (journal->j_flags & JBD2_FLUSHED) { 389 jbd2_debug(3, "super block updated\n"); 390 mutex_lock_io(&journal->j_checkpoint_mutex); 391 /* 392 * We hold j_checkpoint_mutex so tail cannot change under us. 393 * We don't need any special data guarantees for writing sb 394 * since journal is empty and it is ok for write to be 395 * flushed only with transaction commit. 396 */ 397 jbd2_journal_update_sb_log_tail(journal, 398 journal->j_tail_sequence, 399 journal->j_tail, 0); 400 mutex_unlock(&journal->j_checkpoint_mutex); 401 } else { 402 jbd2_debug(3, "superblock not updated\n"); 403 } 404 405 J_ASSERT(journal->j_running_transaction != NULL); 406 J_ASSERT(journal->j_committing_transaction == NULL); 407 408 write_lock(&journal->j_state_lock); 409 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING; 410 while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) { 411 DEFINE_WAIT(wait); 412 413 prepare_to_wait(&journal->j_fc_wait, &wait, 414 TASK_UNINTERRUPTIBLE); 415 write_unlock(&journal->j_state_lock); 416 schedule(); 417 write_lock(&journal->j_state_lock); 418 finish_wait(&journal->j_fc_wait, &wait); 419 /* 420 * TODO: by blocking fast commits here, we are increasing 421 * fsync() latency slightly. Strictly speaking, we don't need 422 * to block fast commits until the transaction enters T_FLUSH 423 * state. So an optimization is possible where we block new fast 424 * commits here and wait for existing ones to complete 425 * just before we enter T_FLUSH. That way, the existing fast 426 * commits and this full commit can proceed parallely. 427 */ 428 } 429 write_unlock(&journal->j_state_lock); 430 431 commit_transaction = journal->j_running_transaction; 432 433 trace_jbd2_start_commit(journal, commit_transaction); 434 jbd2_debug(1, "JBD2: starting commit of transaction %d\n", 435 commit_transaction->t_tid); 436 437 write_lock(&journal->j_state_lock); 438 journal->j_fc_off = 0; 439 J_ASSERT(commit_transaction->t_state == T_RUNNING); 440 commit_transaction->t_state = T_LOCKED; 441 442 trace_jbd2_commit_locking(journal, commit_transaction); 443 stats.run.rs_wait = commit_transaction->t_max_wait; 444 stats.run.rs_request_delay = 0; 445 stats.run.rs_locked = jiffies; 446 if (commit_transaction->t_requested) 447 stats.run.rs_request_delay = 448 jbd2_time_diff(commit_transaction->t_requested, 449 stats.run.rs_locked); 450 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start, 451 stats.run.rs_locked); 452 453 // waits for any t_updates to finish 454 jbd2_journal_wait_updates(journal); 455 456 commit_transaction->t_state = T_SWITCH; 457 458 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <= 459 journal->j_max_transaction_buffers); 460 461 /* 462 * First thing we are allowed to do is to discard any remaining 463 * BJ_Reserved buffers. Note, it is _not_ permissible to assume 464 * that there are no such buffers: if a large filesystem 465 * operation like a truncate needs to split itself over multiple 466 * transactions, then it may try to do a jbd2_journal_restart() while 467 * there are still BJ_Reserved buffers outstanding. These must 468 * be released cleanly from the current transaction. 469 * 470 * In this case, the filesystem must still reserve write access 471 * again before modifying the buffer in the new transaction, but 472 * we do not require it to remember exactly which old buffers it 473 * has reserved. This is consistent with the existing behaviour 474 * that multiple jbd2_journal_get_write_access() calls to the same 475 * buffer are perfectly permissible. 476 * We use journal->j_state_lock here to serialize processing of 477 * t_reserved_list with eviction of buffers from journal_unmap_buffer(). 478 */ 479 while (commit_transaction->t_reserved_list) { 480 jh = commit_transaction->t_reserved_list; 481 JBUFFER_TRACE(jh, "reserved, unused: refile"); 482 /* 483 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may 484 * leave undo-committed data. 485 */ 486 if (jh->b_committed_data) { 487 struct buffer_head *bh = jh2bh(jh); 488 489 spin_lock(&jh->b_state_lock); 490 jbd2_free(jh->b_committed_data, bh->b_size); 491 jh->b_committed_data = NULL; 492 spin_unlock(&jh->b_state_lock); 493 } 494 jbd2_journal_refile_buffer(journal, jh); 495 } 496 497 write_unlock(&journal->j_state_lock); 498 /* 499 * Now try to drop any written-back buffers from the journal's 500 * checkpoint lists. We do this *before* commit because it potentially 501 * frees some memory 502 */ 503 spin_lock(&journal->j_list_lock); 504 __jbd2_journal_clean_checkpoint_list(journal, false); 505 spin_unlock(&journal->j_list_lock); 506 507 jbd2_debug(3, "JBD2: commit phase 1\n"); 508 509 /* 510 * Clear revoked flag to reflect there is no revoked buffers 511 * in the next transaction which is going to be started. 512 */ 513 jbd2_clear_buffer_revoked_flags(journal); 514 515 /* 516 * Switch to a new revoke table. 517 */ 518 jbd2_journal_switch_revoke_table(journal); 519 520 write_lock(&journal->j_state_lock); 521 /* 522 * Reserved credits cannot be claimed anymore, free them 523 */ 524 atomic_sub(atomic_read(&journal->j_reserved_credits), 525 &commit_transaction->t_outstanding_credits); 526 527 trace_jbd2_commit_flushing(journal, commit_transaction); 528 stats.run.rs_flushing = jiffies; 529 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked, 530 stats.run.rs_flushing); 531 532 commit_transaction->t_state = T_FLUSH; 533 journal->j_committing_transaction = commit_transaction; 534 journal->j_running_transaction = NULL; 535 start_time = ktime_get(); 536 commit_transaction->t_log_start = journal->j_head; 537 wake_up_all(&journal->j_wait_transaction_locked); 538 write_unlock(&journal->j_state_lock); 539 540 jbd2_debug(3, "JBD2: commit phase 2a\n"); 541 542 /* 543 * Now start flushing things to disk, in the order they appear 544 * on the transaction lists. Data blocks go first. 545 */ 546 err = journal_submit_data_buffers(journal, commit_transaction); 547 if (err) 548 jbd2_journal_abort(journal, err); 549 550 blk_start_plug(&plug); 551 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs); 552 553 jbd2_debug(3, "JBD2: commit phase 2b\n"); 554 555 /* 556 * Way to go: we have now written out all of the data for a 557 * transaction! Now comes the tricky part: we need to write out 558 * metadata. Loop over the transaction's entire buffer list: 559 */ 560 write_lock(&journal->j_state_lock); 561 commit_transaction->t_state = T_COMMIT; 562 write_unlock(&journal->j_state_lock); 563 564 trace_jbd2_commit_logging(journal, commit_transaction); 565 stats.run.rs_logging = jiffies; 566 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing, 567 stats.run.rs_logging); 568 stats.run.rs_blocks = commit_transaction->t_nr_buffers; 569 stats.run.rs_blocks_logged = 0; 570 571 J_ASSERT(commit_transaction->t_nr_buffers <= 572 atomic_read(&commit_transaction->t_outstanding_credits)); 573 574 err = 0; 575 bufs = 0; 576 descriptor = NULL; 577 while (commit_transaction->t_buffers) { 578 579 /* Find the next buffer to be journaled... */ 580 581 jh = commit_transaction->t_buffers; 582 583 /* If we're in abort mode, we just un-journal the buffer and 584 release it. */ 585 586 if (is_journal_aborted(journal)) { 587 clear_buffer_jbddirty(jh2bh(jh)); 588 JBUFFER_TRACE(jh, "journal is aborting: refile"); 589 jbd2_buffer_abort_trigger(jh, 590 jh->b_frozen_data ? 591 jh->b_frozen_triggers : 592 jh->b_triggers); 593 jbd2_journal_refile_buffer(journal, jh); 594 /* If that was the last one, we need to clean up 595 * any descriptor buffers which may have been 596 * already allocated, even if we are now 597 * aborting. */ 598 if (!commit_transaction->t_buffers) 599 goto start_journal_io; 600 continue; 601 } 602 603 /* Make sure we have a descriptor block in which to 604 record the metadata buffer. */ 605 606 if (!descriptor) { 607 J_ASSERT (bufs == 0); 608 609 jbd2_debug(4, "JBD2: get descriptor\n"); 610 611 descriptor = jbd2_journal_get_descriptor_buffer( 612 commit_transaction, 613 JBD2_DESCRIPTOR_BLOCK); 614 if (!descriptor) { 615 jbd2_journal_abort(journal, -EIO); 616 continue; 617 } 618 619 jbd2_debug(4, "JBD2: got buffer %llu (%p)\n", 620 (unsigned long long)descriptor->b_blocknr, 621 descriptor->b_data); 622 tagp = &descriptor->b_data[sizeof(journal_header_t)]; 623 space_left = descriptor->b_size - 624 sizeof(journal_header_t); 625 first_tag = 1; 626 set_buffer_jwrite(descriptor); 627 set_buffer_dirty(descriptor); 628 wbuf[bufs++] = descriptor; 629 630 /* Record it so that we can wait for IO 631 completion later */ 632 BUFFER_TRACE(descriptor, "ph3: file as descriptor"); 633 jbd2_file_log_bh(&log_bufs, descriptor); 634 } 635 636 /* Where is the buffer to be written? */ 637 638 err = jbd2_journal_next_log_block(journal, &blocknr); 639 /* If the block mapping failed, just abandon the buffer 640 and repeat this loop: we'll fall into the 641 refile-on-abort condition above. */ 642 if (err) { 643 jbd2_journal_abort(journal, err); 644 continue; 645 } 646 647 /* 648 * start_this_handle() uses t_outstanding_credits to determine 649 * the free space in the log. 650 */ 651 atomic_dec(&commit_transaction->t_outstanding_credits); 652 653 /* Bump b_count to prevent truncate from stumbling over 654 the shadowed buffer! @@@ This can go if we ever get 655 rid of the shadow pairing of buffers. */ 656 atomic_inc(&jh2bh(jh)->b_count); 657 658 /* 659 * Make a temporary IO buffer with which to write it out 660 * (this will requeue the metadata buffer to BJ_Shadow). 661 */ 662 set_bit(BH_JWrite, &jh2bh(jh)->b_state); 663 JBUFFER_TRACE(jh, "ph3: write metadata"); 664 flags = jbd2_journal_write_metadata_buffer(commit_transaction, 665 jh, &wbuf[bufs], blocknr); 666 if (flags < 0) { 667 jbd2_journal_abort(journal, flags); 668 continue; 669 } 670 jbd2_file_log_bh(&io_bufs, wbuf[bufs]); 671 672 /* Record the new block's tag in the current descriptor 673 buffer */ 674 675 tag_flag = 0; 676 if (flags & 1) 677 tag_flag |= JBD2_FLAG_ESCAPE; 678 if (!first_tag) 679 tag_flag |= JBD2_FLAG_SAME_UUID; 680 681 tag = (journal_block_tag_t *) tagp; 682 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr); 683 tag->t_flags = cpu_to_be16(tag_flag); 684 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs], 685 commit_transaction->t_tid); 686 tagp += tag_bytes; 687 space_left -= tag_bytes; 688 bufs++; 689 690 if (first_tag) { 691 memcpy (tagp, journal->j_uuid, 16); 692 tagp += 16; 693 space_left -= 16; 694 first_tag = 0; 695 } 696 697 /* If there's no more to do, or if the descriptor is full, 698 let the IO rip! */ 699 700 if (bufs == journal->j_wbufsize || 701 commit_transaction->t_buffers == NULL || 702 space_left < tag_bytes + 16 + csum_size) { 703 704 jbd2_debug(4, "JBD2: Submit %d IOs\n", bufs); 705 706 /* Write an end-of-descriptor marker before 707 submitting the IOs. "tag" still points to 708 the last tag we set up. */ 709 710 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG); 711 start_journal_io: 712 if (descriptor) 713 jbd2_descriptor_block_csum_set(journal, 714 descriptor); 715 716 for (i = 0; i < bufs; i++) { 717 struct buffer_head *bh = wbuf[i]; 718 719 /* 720 * Compute checksum. 721 */ 722 if (jbd2_has_feature_checksum(journal)) { 723 crc32_sum = 724 jbd2_checksum_data(crc32_sum, bh); 725 } 726 727 lock_buffer(bh); 728 clear_buffer_dirty(bh); 729 set_buffer_uptodate(bh); 730 bh->b_end_io = journal_end_buffer_io_sync; 731 submit_bh(REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS, 732 bh); 733 } 734 cond_resched(); 735 736 /* Force a new descriptor to be generated next 737 time round the loop. */ 738 descriptor = NULL; 739 bufs = 0; 740 } 741 } 742 743 err = journal_finish_inode_data_buffers(journal, commit_transaction); 744 if (err) { 745 printk(KERN_WARNING 746 "JBD2: Detected IO errors while flushing file data " 747 "on %s\n", journal->j_devname); 748 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR) 749 jbd2_journal_abort(journal, err); 750 err = 0; 751 } 752 753 /* 754 * Get current oldest transaction in the log before we issue flush 755 * to the filesystem device. After the flush we can be sure that 756 * blocks of all older transactions are checkpointed to persistent 757 * storage and we will be safe to update journal start in the 758 * superblock with the numbers we get here. 759 */ 760 update_tail = 761 jbd2_journal_get_log_tail(journal, &first_tid, &first_block); 762 763 write_lock(&journal->j_state_lock); 764 if (update_tail) { 765 long freed = first_block - journal->j_tail; 766 767 if (first_block < journal->j_tail) 768 freed += journal->j_last - journal->j_first; 769 /* Update tail only if we free significant amount of space */ 770 if (freed < jbd2_journal_get_max_txn_bufs(journal)) 771 update_tail = 0; 772 } 773 J_ASSERT(commit_transaction->t_state == T_COMMIT); 774 commit_transaction->t_state = T_COMMIT_DFLUSH; 775 write_unlock(&journal->j_state_lock); 776 777 /* 778 * If the journal is not located on the file system device, 779 * then we must flush the file system device before we issue 780 * the commit record 781 */ 782 if (commit_transaction->t_need_data_flush && 783 (journal->j_fs_dev != journal->j_dev) && 784 (journal->j_flags & JBD2_BARRIER)) 785 blkdev_issue_flush(journal->j_fs_dev); 786 787 /* Done it all: now write the commit record asynchronously. */ 788 if (jbd2_has_feature_async_commit(journal)) { 789 err = journal_submit_commit_record(journal, commit_transaction, 790 &cbh, crc32_sum); 791 if (err) 792 jbd2_journal_abort(journal, err); 793 } 794 795 blk_finish_plug(&plug); 796 797 /* Lo and behold: we have just managed to send a transaction to 798 the log. Before we can commit it, wait for the IO so far to 799 complete. Control buffers being written are on the 800 transaction's t_log_list queue, and metadata buffers are on 801 the io_bufs list. 802 803 Wait for the buffers in reverse order. That way we are 804 less likely to be woken up until all IOs have completed, and 805 so we incur less scheduling load. 806 */ 807 808 jbd2_debug(3, "JBD2: commit phase 3\n"); 809 810 while (!list_empty(&io_bufs)) { 811 struct buffer_head *bh = list_entry(io_bufs.prev, 812 struct buffer_head, 813 b_assoc_buffers); 814 815 wait_on_buffer(bh); 816 cond_resched(); 817 818 if (unlikely(!buffer_uptodate(bh))) 819 err = -EIO; 820 jbd2_unfile_log_bh(bh); 821 stats.run.rs_blocks_logged++; 822 823 /* 824 * The list contains temporary buffer heads created by 825 * jbd2_journal_write_metadata_buffer(). 826 */ 827 BUFFER_TRACE(bh, "dumping temporary bh"); 828 __brelse(bh); 829 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); 830 free_buffer_head(bh); 831 832 /* We also have to refile the corresponding shadowed buffer */ 833 jh = commit_transaction->t_shadow_list->b_tprev; 834 bh = jh2bh(jh); 835 clear_buffer_jwrite(bh); 836 J_ASSERT_BH(bh, buffer_jbddirty(bh)); 837 J_ASSERT_BH(bh, !buffer_shadow(bh)); 838 839 /* The metadata is now released for reuse, but we need 840 to remember it against this transaction so that when 841 we finally commit, we can do any checkpointing 842 required. */ 843 JBUFFER_TRACE(jh, "file as BJ_Forget"); 844 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget); 845 JBUFFER_TRACE(jh, "brelse shadowed buffer"); 846 __brelse(bh); 847 } 848 849 J_ASSERT (commit_transaction->t_shadow_list == NULL); 850 851 jbd2_debug(3, "JBD2: commit phase 4\n"); 852 853 /* Here we wait for the revoke record and descriptor record buffers */ 854 while (!list_empty(&log_bufs)) { 855 struct buffer_head *bh; 856 857 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers); 858 wait_on_buffer(bh); 859 cond_resched(); 860 861 if (unlikely(!buffer_uptodate(bh))) 862 err = -EIO; 863 864 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); 865 clear_buffer_jwrite(bh); 866 jbd2_unfile_log_bh(bh); 867 stats.run.rs_blocks_logged++; 868 __brelse(bh); /* One for getblk */ 869 /* AKPM: bforget here */ 870 } 871 872 if (err) 873 jbd2_journal_abort(journal, err); 874 875 jbd2_debug(3, "JBD2: commit phase 5\n"); 876 write_lock(&journal->j_state_lock); 877 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH); 878 commit_transaction->t_state = T_COMMIT_JFLUSH; 879 write_unlock(&journal->j_state_lock); 880 881 if (!jbd2_has_feature_async_commit(journal)) { 882 err = journal_submit_commit_record(journal, commit_transaction, 883 &cbh, crc32_sum); 884 if (err) 885 jbd2_journal_abort(journal, err); 886 } 887 if (cbh) 888 err = journal_wait_on_commit_record(journal, cbh); 889 stats.run.rs_blocks_logged++; 890 if (jbd2_has_feature_async_commit(journal) && 891 journal->j_flags & JBD2_BARRIER) { 892 blkdev_issue_flush(journal->j_dev); 893 } 894 895 if (err) 896 jbd2_journal_abort(journal, err); 897 898 WARN_ON_ONCE( 899 atomic_read(&commit_transaction->t_outstanding_credits) < 0); 900 901 /* 902 * Now disk caches for filesystem device are flushed so we are safe to 903 * erase checkpointed transactions from the log by updating journal 904 * superblock. 905 */ 906 if (update_tail) 907 jbd2_update_log_tail(journal, first_tid, first_block); 908 909 /* End of a transaction! Finally, we can do checkpoint 910 processing: any buffers committed as a result of this 911 transaction can be removed from any checkpoint list it was on 912 before. */ 913 914 jbd2_debug(3, "JBD2: commit phase 6\n"); 915 916 J_ASSERT(list_empty(&commit_transaction->t_inode_list)); 917 J_ASSERT(commit_transaction->t_buffers == NULL); 918 J_ASSERT(commit_transaction->t_checkpoint_list == NULL); 919 J_ASSERT(commit_transaction->t_shadow_list == NULL); 920 921 restart_loop: 922 /* 923 * As there are other places (journal_unmap_buffer()) adding buffers 924 * to this list we have to be careful and hold the j_list_lock. 925 */ 926 spin_lock(&journal->j_list_lock); 927 while (commit_transaction->t_forget) { 928 transaction_t *cp_transaction; 929 struct buffer_head *bh; 930 int try_to_free = 0; 931 bool drop_ref; 932 933 jh = commit_transaction->t_forget; 934 spin_unlock(&journal->j_list_lock); 935 bh = jh2bh(jh); 936 /* 937 * Get a reference so that bh cannot be freed before we are 938 * done with it. 939 */ 940 get_bh(bh); 941 spin_lock(&jh->b_state_lock); 942 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction); 943 944 /* 945 * If there is undo-protected committed data against 946 * this buffer, then we can remove it now. If it is a 947 * buffer needing such protection, the old frozen_data 948 * field now points to a committed version of the 949 * buffer, so rotate that field to the new committed 950 * data. 951 * 952 * Otherwise, we can just throw away the frozen data now. 953 * 954 * We also know that the frozen data has already fired 955 * its triggers if they exist, so we can clear that too. 956 */ 957 if (jh->b_committed_data) { 958 jbd2_free(jh->b_committed_data, bh->b_size); 959 jh->b_committed_data = NULL; 960 if (jh->b_frozen_data) { 961 jh->b_committed_data = jh->b_frozen_data; 962 jh->b_frozen_data = NULL; 963 jh->b_frozen_triggers = NULL; 964 } 965 } else if (jh->b_frozen_data) { 966 jbd2_free(jh->b_frozen_data, bh->b_size); 967 jh->b_frozen_data = NULL; 968 jh->b_frozen_triggers = NULL; 969 } 970 971 spin_lock(&journal->j_list_lock); 972 cp_transaction = jh->b_cp_transaction; 973 if (cp_transaction) { 974 JBUFFER_TRACE(jh, "remove from old cp transaction"); 975 cp_transaction->t_chp_stats.cs_dropped++; 976 __jbd2_journal_remove_checkpoint(jh); 977 } 978 979 /* Only re-checkpoint the buffer_head if it is marked 980 * dirty. If the buffer was added to the BJ_Forget list 981 * by jbd2_journal_forget, it may no longer be dirty and 982 * there's no point in keeping a checkpoint record for 983 * it. */ 984 985 /* 986 * A buffer which has been freed while still being journaled 987 * by a previous transaction, refile the buffer to BJ_Forget of 988 * the running transaction. If the just committed transaction 989 * contains "add to orphan" operation, we can completely 990 * invalidate the buffer now. We are rather through in that 991 * since the buffer may be still accessible when blocksize < 992 * pagesize and it is attached to the last partial page. 993 */ 994 if (buffer_freed(bh) && !jh->b_next_transaction) { 995 struct address_space *mapping; 996 997 clear_buffer_freed(bh); 998 clear_buffer_jbddirty(bh); 999 1000 /* 1001 * Block device buffers need to stay mapped all the 1002 * time, so it is enough to clear buffer_jbddirty and 1003 * buffer_freed bits. For the file mapping buffers (i.e. 1004 * journalled data) we need to unmap buffer and clear 1005 * more bits. We also need to be careful about the check 1006 * because the data page mapping can get cleared under 1007 * our hands. Note that if mapping == NULL, we don't 1008 * need to make buffer unmapped because the page is 1009 * already detached from the mapping and buffers cannot 1010 * get reused. 1011 */ 1012 mapping = READ_ONCE(bh->b_folio->mapping); 1013 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) { 1014 clear_buffer_mapped(bh); 1015 clear_buffer_new(bh); 1016 clear_buffer_req(bh); 1017 bh->b_bdev = NULL; 1018 } 1019 } 1020 1021 if (buffer_jbddirty(bh)) { 1022 JBUFFER_TRACE(jh, "add to new checkpointing trans"); 1023 __jbd2_journal_insert_checkpoint(jh, commit_transaction); 1024 if (is_journal_aborted(journal)) 1025 clear_buffer_jbddirty(bh); 1026 } else { 1027 J_ASSERT_BH(bh, !buffer_dirty(bh)); 1028 /* 1029 * The buffer on BJ_Forget list and not jbddirty means 1030 * it has been freed by this transaction and hence it 1031 * could not have been reallocated until this 1032 * transaction has committed. *BUT* it could be 1033 * reallocated once we have written all the data to 1034 * disk and before we process the buffer on BJ_Forget 1035 * list. 1036 */ 1037 if (!jh->b_next_transaction) 1038 try_to_free = 1; 1039 } 1040 JBUFFER_TRACE(jh, "refile or unfile buffer"); 1041 drop_ref = __jbd2_journal_refile_buffer(jh); 1042 spin_unlock(&jh->b_state_lock); 1043 if (drop_ref) 1044 jbd2_journal_put_journal_head(jh); 1045 if (try_to_free) 1046 release_buffer_page(bh); /* Drops bh reference */ 1047 else 1048 __brelse(bh); 1049 cond_resched_lock(&journal->j_list_lock); 1050 } 1051 spin_unlock(&journal->j_list_lock); 1052 /* 1053 * This is a bit sleazy. We use j_list_lock to protect transition 1054 * of a transaction into T_FINISHED state and calling 1055 * __jbd2_journal_drop_transaction(). Otherwise we could race with 1056 * other checkpointing code processing the transaction... 1057 */ 1058 write_lock(&journal->j_state_lock); 1059 spin_lock(&journal->j_list_lock); 1060 /* 1061 * Now recheck if some buffers did not get attached to the transaction 1062 * while the lock was dropped... 1063 */ 1064 if (commit_transaction->t_forget) { 1065 spin_unlock(&journal->j_list_lock); 1066 write_unlock(&journal->j_state_lock); 1067 goto restart_loop; 1068 } 1069 1070 /* Add the transaction to the checkpoint list 1071 * __journal_remove_checkpoint() can not destroy transaction 1072 * under us because it is not marked as T_FINISHED yet */ 1073 if (journal->j_checkpoint_transactions == NULL) { 1074 journal->j_checkpoint_transactions = commit_transaction; 1075 commit_transaction->t_cpnext = commit_transaction; 1076 commit_transaction->t_cpprev = commit_transaction; 1077 } else { 1078 commit_transaction->t_cpnext = 1079 journal->j_checkpoint_transactions; 1080 commit_transaction->t_cpprev = 1081 commit_transaction->t_cpnext->t_cpprev; 1082 commit_transaction->t_cpnext->t_cpprev = 1083 commit_transaction; 1084 commit_transaction->t_cpprev->t_cpnext = 1085 commit_transaction; 1086 } 1087 spin_unlock(&journal->j_list_lock); 1088 1089 /* Done with this transaction! */ 1090 1091 jbd2_debug(3, "JBD2: commit phase 7\n"); 1092 1093 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH); 1094 1095 commit_transaction->t_start = jiffies; 1096 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging, 1097 commit_transaction->t_start); 1098 1099 /* 1100 * File the transaction statistics 1101 */ 1102 stats.ts_tid = commit_transaction->t_tid; 1103 stats.run.rs_handle_count = 1104 atomic_read(&commit_transaction->t_handle_count); 1105 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev, 1106 commit_transaction->t_tid, &stats.run); 1107 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0; 1108 1109 commit_transaction->t_state = T_COMMIT_CALLBACK; 1110 J_ASSERT(commit_transaction == journal->j_committing_transaction); 1111 journal->j_commit_sequence = commit_transaction->t_tid; 1112 journal->j_committing_transaction = NULL; 1113 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); 1114 1115 /* 1116 * weight the commit time higher than the average time so we don't 1117 * react too strongly to vast changes in the commit time 1118 */ 1119 if (likely(journal->j_average_commit_time)) 1120 journal->j_average_commit_time = (commit_time + 1121 journal->j_average_commit_time*3) / 4; 1122 else 1123 journal->j_average_commit_time = commit_time; 1124 1125 write_unlock(&journal->j_state_lock); 1126 1127 if (journal->j_commit_callback) 1128 journal->j_commit_callback(journal, commit_transaction); 1129 if (journal->j_fc_cleanup_callback) 1130 journal->j_fc_cleanup_callback(journal, 1, commit_transaction->t_tid); 1131 1132 trace_jbd2_end_commit(journal, commit_transaction); 1133 jbd2_debug(1, "JBD2: commit %d complete, head %d\n", 1134 journal->j_commit_sequence, journal->j_tail_sequence); 1135 1136 write_lock(&journal->j_state_lock); 1137 journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING; 1138 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING; 1139 spin_lock(&journal->j_list_lock); 1140 commit_transaction->t_state = T_FINISHED; 1141 /* Check if the transaction can be dropped now that we are finished */ 1142 if (commit_transaction->t_checkpoint_list == NULL) { 1143 __jbd2_journal_drop_transaction(journal, commit_transaction); 1144 jbd2_journal_free_transaction(commit_transaction); 1145 } 1146 spin_unlock(&journal->j_list_lock); 1147 write_unlock(&journal->j_state_lock); 1148 wake_up(&journal->j_wait_done_commit); 1149 wake_up(&journal->j_fc_wait); 1150 1151 /* 1152 * Calculate overall stats 1153 */ 1154 spin_lock(&journal->j_history_lock); 1155 journal->j_stats.ts_tid++; 1156 journal->j_stats.ts_requested += stats.ts_requested; 1157 journal->j_stats.run.rs_wait += stats.run.rs_wait; 1158 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay; 1159 journal->j_stats.run.rs_running += stats.run.rs_running; 1160 journal->j_stats.run.rs_locked += stats.run.rs_locked; 1161 journal->j_stats.run.rs_flushing += stats.run.rs_flushing; 1162 journal->j_stats.run.rs_logging += stats.run.rs_logging; 1163 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count; 1164 journal->j_stats.run.rs_blocks += stats.run.rs_blocks; 1165 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged; 1166 spin_unlock(&journal->j_history_lock); 1167 } 1168