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 spin_lock(&jh->b_state_lock); 486 jbd2_free(jh->b_committed_data, bh->b_size); 487 jh->b_committed_data = NULL; 488 spin_unlock(&jh->b_state_lock); 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 = commit_transaction->t_nr_buffers; 564 stats.run.rs_blocks_logged = 0; 565 566 J_ASSERT(commit_transaction->t_nr_buffers <= 567 atomic_read(&commit_transaction->t_outstanding_credits)); 568 569 err = 0; 570 bufs = 0; 571 descriptor = NULL; 572 while (commit_transaction->t_buffers) { 573 574 /* Find the next buffer to be journaled... */ 575 576 jh = commit_transaction->t_buffers; 577 578 /* If we're in abort mode, we just un-journal the buffer and 579 release it. */ 580 581 if (is_journal_aborted(journal)) { 582 clear_buffer_jbddirty(jh2bh(jh)); 583 JBUFFER_TRACE(jh, "journal is aborting: refile"); 584 jbd2_buffer_abort_trigger(jh, 585 jh->b_frozen_data ? 586 jh->b_frozen_triggers : 587 jh->b_triggers); 588 jbd2_journal_refile_buffer(journal, jh); 589 /* If that was the last one, we need to clean up 590 * any descriptor buffers which may have been 591 * already allocated, even if we are now 592 * aborting. */ 593 if (!commit_transaction->t_buffers) 594 goto start_journal_io; 595 continue; 596 } 597 598 /* Make sure we have a descriptor block in which to 599 record the metadata buffer. */ 600 601 if (!descriptor) { 602 J_ASSERT (bufs == 0); 603 604 jbd_debug(4, "JBD2: get descriptor\n"); 605 606 descriptor = jbd2_journal_get_descriptor_buffer( 607 commit_transaction, 608 JBD2_DESCRIPTOR_BLOCK); 609 if (!descriptor) { 610 jbd2_journal_abort(journal, -EIO); 611 continue; 612 } 613 614 jbd_debug(4, "JBD2: got buffer %llu (%p)\n", 615 (unsigned long long)descriptor->b_blocknr, 616 descriptor->b_data); 617 tagp = &descriptor->b_data[sizeof(journal_header_t)]; 618 space_left = descriptor->b_size - 619 sizeof(journal_header_t); 620 first_tag = 1; 621 set_buffer_jwrite(descriptor); 622 set_buffer_dirty(descriptor); 623 wbuf[bufs++] = descriptor; 624 625 /* Record it so that we can wait for IO 626 completion later */ 627 BUFFER_TRACE(descriptor, "ph3: file as descriptor"); 628 jbd2_file_log_bh(&log_bufs, descriptor); 629 } 630 631 /* Where is the buffer to be written? */ 632 633 err = jbd2_journal_next_log_block(journal, &blocknr); 634 /* If the block mapping failed, just abandon the buffer 635 and repeat this loop: we'll fall into the 636 refile-on-abort condition above. */ 637 if (err) { 638 jbd2_journal_abort(journal, err); 639 continue; 640 } 641 642 /* 643 * start_this_handle() uses t_outstanding_credits to determine 644 * the free space in the log. 645 */ 646 atomic_dec(&commit_transaction->t_outstanding_credits); 647 648 /* Bump b_count to prevent truncate from stumbling over 649 the shadowed buffer! @@@ This can go if we ever get 650 rid of the shadow pairing of buffers. */ 651 atomic_inc(&jh2bh(jh)->b_count); 652 653 /* 654 * Make a temporary IO buffer with which to write it out 655 * (this will requeue the metadata buffer to BJ_Shadow). 656 */ 657 set_bit(BH_JWrite, &jh2bh(jh)->b_state); 658 JBUFFER_TRACE(jh, "ph3: write metadata"); 659 flags = jbd2_journal_write_metadata_buffer(commit_transaction, 660 jh, &wbuf[bufs], blocknr); 661 if (flags < 0) { 662 jbd2_journal_abort(journal, flags); 663 continue; 664 } 665 jbd2_file_log_bh(&io_bufs, wbuf[bufs]); 666 667 /* Record the new block's tag in the current descriptor 668 buffer */ 669 670 tag_flag = 0; 671 if (flags & 1) 672 tag_flag |= JBD2_FLAG_ESCAPE; 673 if (!first_tag) 674 tag_flag |= JBD2_FLAG_SAME_UUID; 675 676 tag = (journal_block_tag_t *) tagp; 677 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr); 678 tag->t_flags = cpu_to_be16(tag_flag); 679 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs], 680 commit_transaction->t_tid); 681 tagp += tag_bytes; 682 space_left -= tag_bytes; 683 bufs++; 684 685 if (first_tag) { 686 memcpy (tagp, journal->j_uuid, 16); 687 tagp += 16; 688 space_left -= 16; 689 first_tag = 0; 690 } 691 692 /* If there's no more to do, or if the descriptor is full, 693 let the IO rip! */ 694 695 if (bufs == journal->j_wbufsize || 696 commit_transaction->t_buffers == NULL || 697 space_left < tag_bytes + 16 + csum_size) { 698 699 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs); 700 701 /* Write an end-of-descriptor marker before 702 submitting the IOs. "tag" still points to 703 the last tag we set up. */ 704 705 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG); 706 start_journal_io: 707 if (descriptor) 708 jbd2_descriptor_block_csum_set(journal, 709 descriptor); 710 711 for (i = 0; i < bufs; i++) { 712 struct buffer_head *bh = wbuf[i]; 713 /* 714 * Compute checksum. 715 */ 716 if (jbd2_has_feature_checksum(journal)) { 717 crc32_sum = 718 jbd2_checksum_data(crc32_sum, bh); 719 } 720 721 lock_buffer(bh); 722 clear_buffer_dirty(bh); 723 set_buffer_uptodate(bh); 724 bh->b_end_io = journal_end_buffer_io_sync; 725 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh); 726 } 727 cond_resched(); 728 729 /* Force a new descriptor to be generated next 730 time round the loop. */ 731 descriptor = NULL; 732 bufs = 0; 733 } 734 } 735 736 err = journal_finish_inode_data_buffers(journal, commit_transaction); 737 if (err) { 738 printk(KERN_WARNING 739 "JBD2: Detected IO errors while flushing file data " 740 "on %s\n", journal->j_devname); 741 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR) 742 jbd2_journal_abort(journal, err); 743 err = 0; 744 } 745 746 /* 747 * Get current oldest transaction in the log before we issue flush 748 * to the filesystem device. After the flush we can be sure that 749 * blocks of all older transactions are checkpointed to persistent 750 * storage and we will be safe to update journal start in the 751 * superblock with the numbers we get here. 752 */ 753 update_tail = 754 jbd2_journal_get_log_tail(journal, &first_tid, &first_block); 755 756 write_lock(&journal->j_state_lock); 757 if (update_tail) { 758 long freed = first_block - journal->j_tail; 759 760 if (first_block < journal->j_tail) 761 freed += journal->j_last - journal->j_first; 762 /* Update tail only if we free significant amount of space */ 763 if (freed < journal->j_maxlen / 4) 764 update_tail = 0; 765 } 766 J_ASSERT(commit_transaction->t_state == T_COMMIT); 767 commit_transaction->t_state = T_COMMIT_DFLUSH; 768 write_unlock(&journal->j_state_lock); 769 770 /* 771 * If the journal is not located on the file system device, 772 * then we must flush the file system device before we issue 773 * the commit record 774 */ 775 if (commit_transaction->t_need_data_flush && 776 (journal->j_fs_dev != journal->j_dev) && 777 (journal->j_flags & JBD2_BARRIER)) 778 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL); 779 780 /* Done it all: now write the commit record asynchronously. */ 781 if (jbd2_has_feature_async_commit(journal)) { 782 err = journal_submit_commit_record(journal, commit_transaction, 783 &cbh, crc32_sum); 784 if (err) 785 __jbd2_journal_abort_hard(journal); 786 } 787 788 blk_finish_plug(&plug); 789 790 /* Lo and behold: we have just managed to send a transaction to 791 the log. Before we can commit it, wait for the IO so far to 792 complete. Control buffers being written are on the 793 transaction's t_log_list queue, and metadata buffers are on 794 the io_bufs list. 795 796 Wait for the buffers in reverse order. That way we are 797 less likely to be woken up until all IOs have completed, and 798 so we incur less scheduling load. 799 */ 800 801 jbd_debug(3, "JBD2: commit phase 3\n"); 802 803 while (!list_empty(&io_bufs)) { 804 struct buffer_head *bh = list_entry(io_bufs.prev, 805 struct buffer_head, 806 b_assoc_buffers); 807 808 wait_on_buffer(bh); 809 cond_resched(); 810 811 if (unlikely(!buffer_uptodate(bh))) 812 err = -EIO; 813 jbd2_unfile_log_bh(bh); 814 stats.run.rs_blocks_logged++; 815 816 /* 817 * The list contains temporary buffer heads created by 818 * jbd2_journal_write_metadata_buffer(). 819 */ 820 BUFFER_TRACE(bh, "dumping temporary bh"); 821 __brelse(bh); 822 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); 823 free_buffer_head(bh); 824 825 /* We also have to refile the corresponding shadowed buffer */ 826 jh = commit_transaction->t_shadow_list->b_tprev; 827 bh = jh2bh(jh); 828 clear_buffer_jwrite(bh); 829 J_ASSERT_BH(bh, buffer_jbddirty(bh)); 830 J_ASSERT_BH(bh, !buffer_shadow(bh)); 831 832 /* The metadata is now released for reuse, but we need 833 to remember it against this transaction so that when 834 we finally commit, we can do any checkpointing 835 required. */ 836 JBUFFER_TRACE(jh, "file as BJ_Forget"); 837 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget); 838 JBUFFER_TRACE(jh, "brelse shadowed buffer"); 839 __brelse(bh); 840 } 841 842 J_ASSERT (commit_transaction->t_shadow_list == NULL); 843 844 jbd_debug(3, "JBD2: commit phase 4\n"); 845 846 /* Here we wait for the revoke record and descriptor record buffers */ 847 while (!list_empty(&log_bufs)) { 848 struct buffer_head *bh; 849 850 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers); 851 wait_on_buffer(bh); 852 cond_resched(); 853 854 if (unlikely(!buffer_uptodate(bh))) 855 err = -EIO; 856 857 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); 858 clear_buffer_jwrite(bh); 859 jbd2_unfile_log_bh(bh); 860 stats.run.rs_blocks_logged++; 861 __brelse(bh); /* One for getblk */ 862 /* AKPM: bforget here */ 863 } 864 865 if (err) 866 jbd2_journal_abort(journal, err); 867 868 jbd_debug(3, "JBD2: commit phase 5\n"); 869 write_lock(&journal->j_state_lock); 870 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH); 871 commit_transaction->t_state = T_COMMIT_JFLUSH; 872 write_unlock(&journal->j_state_lock); 873 874 if (!jbd2_has_feature_async_commit(journal)) { 875 err = journal_submit_commit_record(journal, commit_transaction, 876 &cbh, crc32_sum); 877 if (err) 878 __jbd2_journal_abort_hard(journal); 879 } 880 if (cbh) 881 err = journal_wait_on_commit_record(journal, cbh); 882 stats.run.rs_blocks_logged++; 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 WARN_ON_ONCE( 892 atomic_read(&commit_transaction->t_outstanding_credits) < 0); 893 894 /* 895 * Now disk caches for filesystem device are flushed so we are safe to 896 * erase checkpointed transactions from the log by updating journal 897 * superblock. 898 */ 899 if (update_tail) 900 jbd2_update_log_tail(journal, first_tid, first_block); 901 902 /* End of a transaction! Finally, we can do checkpoint 903 processing: any buffers committed as a result of this 904 transaction can be removed from any checkpoint list it was on 905 before. */ 906 907 jbd_debug(3, "JBD2: commit phase 6\n"); 908 909 J_ASSERT(list_empty(&commit_transaction->t_inode_list)); 910 J_ASSERT(commit_transaction->t_buffers == NULL); 911 J_ASSERT(commit_transaction->t_checkpoint_list == NULL); 912 J_ASSERT(commit_transaction->t_shadow_list == NULL); 913 914 restart_loop: 915 /* 916 * As there are other places (journal_unmap_buffer()) adding buffers 917 * to this list we have to be careful and hold the j_list_lock. 918 */ 919 spin_lock(&journal->j_list_lock); 920 while (commit_transaction->t_forget) { 921 transaction_t *cp_transaction; 922 struct buffer_head *bh; 923 int try_to_free = 0; 924 bool drop_ref; 925 926 jh = commit_transaction->t_forget; 927 spin_unlock(&journal->j_list_lock); 928 bh = jh2bh(jh); 929 /* 930 * Get a reference so that bh cannot be freed before we are 931 * done with it. 932 */ 933 get_bh(bh); 934 spin_lock(&jh->b_state_lock); 935 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction); 936 937 /* 938 * If there is undo-protected committed data against 939 * this buffer, then we can remove it now. If it is a 940 * buffer needing such protection, the old frozen_data 941 * field now points to a committed version of the 942 * buffer, so rotate that field to the new committed 943 * data. 944 * 945 * Otherwise, we can just throw away the frozen data now. 946 * 947 * We also know that the frozen data has already fired 948 * its triggers if they exist, so we can clear that too. 949 */ 950 if (jh->b_committed_data) { 951 jbd2_free(jh->b_committed_data, bh->b_size); 952 jh->b_committed_data = NULL; 953 if (jh->b_frozen_data) { 954 jh->b_committed_data = jh->b_frozen_data; 955 jh->b_frozen_data = NULL; 956 jh->b_frozen_triggers = NULL; 957 } 958 } else if (jh->b_frozen_data) { 959 jbd2_free(jh->b_frozen_data, bh->b_size); 960 jh->b_frozen_data = NULL; 961 jh->b_frozen_triggers = NULL; 962 } 963 964 spin_lock(&journal->j_list_lock); 965 cp_transaction = jh->b_cp_transaction; 966 if (cp_transaction) { 967 JBUFFER_TRACE(jh, "remove from old cp transaction"); 968 cp_transaction->t_chp_stats.cs_dropped++; 969 __jbd2_journal_remove_checkpoint(jh); 970 } 971 972 /* Only re-checkpoint the buffer_head if it is marked 973 * dirty. If the buffer was added to the BJ_Forget list 974 * by jbd2_journal_forget, it may no longer be dirty and 975 * there's no point in keeping a checkpoint record for 976 * it. */ 977 978 /* 979 * A buffer which has been freed while still being journaled by 980 * a previous transaction. 981 */ 982 if (buffer_freed(bh)) { 983 /* 984 * If the running transaction is the one containing 985 * "add to orphan" operation (b_next_transaction != 986 * NULL), we have to wait for that transaction to 987 * commit before we can really get rid of the buffer. 988 * So just clear b_modified to not confuse transaction 989 * credit accounting and refile the buffer to 990 * BJ_Forget of the running transaction. If the just 991 * committed transaction contains "add to orphan" 992 * operation, we can completely invalidate the buffer 993 * now. We are rather through in that since the 994 * buffer may be still accessible when blocksize < 995 * pagesize and it is attached to the last partial 996 * page. 997 */ 998 jh->b_modified = 0; 999 if (!jh->b_next_transaction) { 1000 clear_buffer_freed(bh); 1001 clear_buffer_jbddirty(bh); 1002 clear_buffer_mapped(bh); 1003 clear_buffer_new(bh); 1004 clear_buffer_req(bh); 1005 bh->b_bdev = NULL; 1006 } 1007 } 1008 1009 if (buffer_jbddirty(bh)) { 1010 JBUFFER_TRACE(jh, "add to new checkpointing trans"); 1011 __jbd2_journal_insert_checkpoint(jh, commit_transaction); 1012 if (is_journal_aborted(journal)) 1013 clear_buffer_jbddirty(bh); 1014 } else { 1015 J_ASSERT_BH(bh, !buffer_dirty(bh)); 1016 /* 1017 * The buffer on BJ_Forget list and not jbddirty means 1018 * it has been freed by this transaction and hence it 1019 * could not have been reallocated until this 1020 * transaction has committed. *BUT* it could be 1021 * reallocated once we have written all the data to 1022 * disk and before we process the buffer on BJ_Forget 1023 * list. 1024 */ 1025 if (!jh->b_next_transaction) 1026 try_to_free = 1; 1027 } 1028 JBUFFER_TRACE(jh, "refile or unfile buffer"); 1029 drop_ref = __jbd2_journal_refile_buffer(jh); 1030 spin_unlock(&jh->b_state_lock); 1031 if (drop_ref) 1032 jbd2_journal_put_journal_head(jh); 1033 if (try_to_free) 1034 release_buffer_page(bh); /* Drops bh reference */ 1035 else 1036 __brelse(bh); 1037 cond_resched_lock(&journal->j_list_lock); 1038 } 1039 spin_unlock(&journal->j_list_lock); 1040 /* 1041 * This is a bit sleazy. We use j_list_lock to protect transition 1042 * of a transaction into T_FINISHED state and calling 1043 * __jbd2_journal_drop_transaction(). Otherwise we could race with 1044 * other checkpointing code processing the transaction... 1045 */ 1046 write_lock(&journal->j_state_lock); 1047 spin_lock(&journal->j_list_lock); 1048 /* 1049 * Now recheck if some buffers did not get attached to the transaction 1050 * while the lock was dropped... 1051 */ 1052 if (commit_transaction->t_forget) { 1053 spin_unlock(&journal->j_list_lock); 1054 write_unlock(&journal->j_state_lock); 1055 goto restart_loop; 1056 } 1057 1058 /* Add the transaction to the checkpoint list 1059 * __journal_remove_checkpoint() can not destroy transaction 1060 * under us because it is not marked as T_FINISHED yet */ 1061 if (journal->j_checkpoint_transactions == NULL) { 1062 journal->j_checkpoint_transactions = commit_transaction; 1063 commit_transaction->t_cpnext = commit_transaction; 1064 commit_transaction->t_cpprev = commit_transaction; 1065 } else { 1066 commit_transaction->t_cpnext = 1067 journal->j_checkpoint_transactions; 1068 commit_transaction->t_cpprev = 1069 commit_transaction->t_cpnext->t_cpprev; 1070 commit_transaction->t_cpnext->t_cpprev = 1071 commit_transaction; 1072 commit_transaction->t_cpprev->t_cpnext = 1073 commit_transaction; 1074 } 1075 spin_unlock(&journal->j_list_lock); 1076 1077 /* Done with this transaction! */ 1078 1079 jbd_debug(3, "JBD2: commit phase 7\n"); 1080 1081 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH); 1082 1083 commit_transaction->t_start = jiffies; 1084 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging, 1085 commit_transaction->t_start); 1086 1087 /* 1088 * File the transaction statistics 1089 */ 1090 stats.ts_tid = commit_transaction->t_tid; 1091 stats.run.rs_handle_count = 1092 atomic_read(&commit_transaction->t_handle_count); 1093 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev, 1094 commit_transaction->t_tid, &stats.run); 1095 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0; 1096 1097 commit_transaction->t_state = T_COMMIT_CALLBACK; 1098 J_ASSERT(commit_transaction == journal->j_committing_transaction); 1099 journal->j_commit_sequence = commit_transaction->t_tid; 1100 journal->j_committing_transaction = NULL; 1101 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); 1102 1103 /* 1104 * weight the commit time higher than the average time so we don't 1105 * react too strongly to vast changes in the commit time 1106 */ 1107 if (likely(journal->j_average_commit_time)) 1108 journal->j_average_commit_time = (commit_time + 1109 journal->j_average_commit_time*3) / 4; 1110 else 1111 journal->j_average_commit_time = commit_time; 1112 1113 write_unlock(&journal->j_state_lock); 1114 1115 if (journal->j_commit_callback) 1116 journal->j_commit_callback(journal, commit_transaction); 1117 1118 trace_jbd2_end_commit(journal, commit_transaction); 1119 jbd_debug(1, "JBD2: commit %d complete, head %d\n", 1120 journal->j_commit_sequence, journal->j_tail_sequence); 1121 1122 write_lock(&journal->j_state_lock); 1123 spin_lock(&journal->j_list_lock); 1124 commit_transaction->t_state = T_FINISHED; 1125 /* Check if the transaction can be dropped now that we are finished */ 1126 if (commit_transaction->t_checkpoint_list == NULL && 1127 commit_transaction->t_checkpoint_io_list == NULL) { 1128 __jbd2_journal_drop_transaction(journal, commit_transaction); 1129 jbd2_journal_free_transaction(commit_transaction); 1130 } 1131 spin_unlock(&journal->j_list_lock); 1132 write_unlock(&journal->j_state_lock); 1133 wake_up(&journal->j_wait_done_commit); 1134 1135 /* 1136 * Calculate overall stats 1137 */ 1138 spin_lock(&journal->j_history_lock); 1139 journal->j_stats.ts_tid++; 1140 journal->j_stats.ts_requested += stats.ts_requested; 1141 journal->j_stats.run.rs_wait += stats.run.rs_wait; 1142 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay; 1143 journal->j_stats.run.rs_running += stats.run.rs_running; 1144 journal->j_stats.run.rs_locked += stats.run.rs_locked; 1145 journal->j_stats.run.rs_flushing += stats.run.rs_flushing; 1146 journal->j_stats.run.rs_logging += stats.run.rs_logging; 1147 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count; 1148 journal->j_stats.run.rs_blocks += stats.run.rs_blocks; 1149 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged; 1150 spin_unlock(&journal->j_history_lock); 1151 } 1152