1 /* 2 * linux/fs/jbd2/commit.c 3 * 4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998 5 * 6 * Copyright 1998 Red Hat corp --- All Rights Reserved 7 * 8 * This file is part of the Linux kernel and is made available under 9 * the terms of the GNU General Public License, version 2, or at your 10 * option, any later version, incorporated herein by reference. 11 * 12 * Journal commit routines for the generic filesystem journaling code; 13 * part of the ext2fs journaling system. 14 */ 15 16 #include <linux/time.h> 17 #include <linux/fs.h> 18 #include <linux/jbd2.h> 19 #include <linux/errno.h> 20 #include <linux/slab.h> 21 #include <linux/mm.h> 22 #include <linux/pagemap.h> 23 #include <linux/jiffies.h> 24 #include <linux/crc32.h> 25 #include <linux/writeback.h> 26 #include <linux/backing-dev.h> 27 #include <linux/bio.h> 28 #include <linux/blkdev.h> 29 #include <linux/bitops.h> 30 #include <trace/events/jbd2.h> 31 32 /* 33 * IO end handler for temporary buffer_heads handling writes to the journal. 34 */ 35 static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate) 36 { 37 struct buffer_head *orig_bh = bh->b_private; 38 39 BUFFER_TRACE(bh, ""); 40 if (uptodate) 41 set_buffer_uptodate(bh); 42 else 43 clear_buffer_uptodate(bh); 44 if (orig_bh) { 45 clear_bit_unlock(BH_Shadow, &orig_bh->b_state); 46 smp_mb__after_atomic(); 47 wake_up_bit(&orig_bh->b_state, BH_Shadow); 48 } 49 unlock_buffer(bh); 50 } 51 52 /* 53 * When an ext4 file is truncated, it is possible that some pages are not 54 * successfully freed, because they are attached to a committing transaction. 55 * After the transaction commits, these pages are left on the LRU, with no 56 * ->mapping, and with attached buffers. These pages are trivially reclaimable 57 * by the VM, but their apparent absence upsets the VM accounting, and it makes 58 * the numbers in /proc/meminfo look odd. 59 * 60 * So here, we have a buffer which has just come off the forget list. Look to 61 * see if we can strip all buffers from the backing page. 62 * 63 * Called under lock_journal(), and possibly under journal_datalist_lock. The 64 * caller provided us with a ref against the buffer, and we drop that here. 65 */ 66 static void release_buffer_page(struct buffer_head *bh) 67 { 68 struct page *page; 69 70 if (buffer_dirty(bh)) 71 goto nope; 72 if (atomic_read(&bh->b_count) != 1) 73 goto nope; 74 page = bh->b_page; 75 if (!page) 76 goto nope; 77 if (page->mapping) 78 goto nope; 79 80 /* OK, it's a truncated page */ 81 if (!trylock_page(page)) 82 goto nope; 83 84 get_page(page); 85 __brelse(bh); 86 try_to_free_buffers(page); 87 unlock_page(page); 88 put_page(page); 89 return; 90 91 nope: 92 __brelse(bh); 93 } 94 95 static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh) 96 { 97 struct commit_header *h; 98 __u32 csum; 99 100 if (!jbd2_journal_has_csum_v2or3(j)) 101 return; 102 103 h = (struct commit_header *)(bh->b_data); 104 h->h_chksum_type = 0; 105 h->h_chksum_size = 0; 106 h->h_chksum[0] = 0; 107 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize); 108 h->h_chksum[0] = cpu_to_be32(csum); 109 } 110 111 /* 112 * Done it all: now submit the commit record. We should have 113 * cleaned up our previous buffers by now, so if we are in abort 114 * mode we can now just skip the rest of the journal write 115 * entirely. 116 * 117 * Returns 1 if the journal needs to be aborted or 0 on success 118 */ 119 static int journal_submit_commit_record(journal_t *journal, 120 transaction_t *commit_transaction, 121 struct buffer_head **cbh, 122 __u32 crc32_sum) 123 { 124 struct commit_header *tmp; 125 struct buffer_head *bh; 126 int ret; 127 struct timespec64 now = current_kernel_time64(); 128 129 *cbh = NULL; 130 131 if (is_journal_aborted(journal)) 132 return 0; 133 134 bh = jbd2_journal_get_descriptor_buffer(commit_transaction, 135 JBD2_COMMIT_BLOCK); 136 if (!bh) 137 return 1; 138 139 tmp = (struct commit_header *)bh->b_data; 140 tmp->h_commit_sec = cpu_to_be64(now.tv_sec); 141 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec); 142 143 if (jbd2_has_feature_checksum(journal)) { 144 tmp->h_chksum_type = JBD2_CRC32_CHKSUM; 145 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE; 146 tmp->h_chksum[0] = cpu_to_be32(crc32_sum); 147 } 148 jbd2_commit_block_csum_set(journal, bh); 149 150 BUFFER_TRACE(bh, "submit commit block"); 151 lock_buffer(bh); 152 clear_buffer_dirty(bh); 153 set_buffer_uptodate(bh); 154 bh->b_end_io = journal_end_buffer_io_sync; 155 156 if (journal->j_flags & JBD2_BARRIER && 157 !jbd2_has_feature_async_commit(journal)) 158 ret = submit_bh(REQ_OP_WRITE, 159 REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh); 160 else 161 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh); 162 163 *cbh = bh; 164 return ret; 165 } 166 167 /* 168 * This function along with journal_submit_commit_record 169 * allows to write the commit record asynchronously. 170 */ 171 static int journal_wait_on_commit_record(journal_t *journal, 172 struct buffer_head *bh) 173 { 174 int ret = 0; 175 176 clear_buffer_dirty(bh); 177 wait_on_buffer(bh); 178 179 if (unlikely(!buffer_uptodate(bh))) 180 ret = -EIO; 181 put_bh(bh); /* One for getblk() */ 182 183 return ret; 184 } 185 186 /* 187 * write the filemap data using writepage() address_space_operations. 188 * We don't do block allocation here even for delalloc. We don't 189 * use writepages() because with dealyed allocation we may be doing 190 * block allocation in writepages(). 191 */ 192 static int journal_submit_inode_data_buffers(struct address_space *mapping) 193 { 194 int ret; 195 struct writeback_control wbc = { 196 .sync_mode = WB_SYNC_ALL, 197 .nr_to_write = mapping->nrpages * 2, 198 .range_start = 0, 199 .range_end = i_size_read(mapping->host), 200 }; 201 202 ret = generic_writepages(mapping, &wbc); 203 return ret; 204 } 205 206 /* 207 * Submit all the data buffers of inode associated with the transaction to 208 * disk. 209 * 210 * We are in a committing transaction. Therefore no new inode can be added to 211 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently 212 * operate on from being released while we write out pages. 213 */ 214 static int journal_submit_data_buffers(journal_t *journal, 215 transaction_t *commit_transaction) 216 { 217 struct jbd2_inode *jinode; 218 int err, ret = 0; 219 struct address_space *mapping; 220 221 spin_lock(&journal->j_list_lock); 222 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 223 if (!(jinode->i_flags & JI_WRITE_DATA)) 224 continue; 225 mapping = jinode->i_vfs_inode->i_mapping; 226 jinode->i_flags |= JI_COMMIT_RUNNING; 227 spin_unlock(&journal->j_list_lock); 228 /* 229 * submit the inode data buffers. We use writepage 230 * instead of writepages. Because writepages can do 231 * block allocation with delalloc. We need to write 232 * only allocated blocks here. 233 */ 234 trace_jbd2_submit_inode_data(jinode->i_vfs_inode); 235 err = journal_submit_inode_data_buffers(mapping); 236 if (!ret) 237 ret = err; 238 spin_lock(&journal->j_list_lock); 239 J_ASSERT(jinode->i_transaction == commit_transaction); 240 jinode->i_flags &= ~JI_COMMIT_RUNNING; 241 smp_mb(); 242 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 243 } 244 spin_unlock(&journal->j_list_lock); 245 return ret; 246 } 247 248 /* 249 * Wait for data submitted for writeout, refile inodes to proper 250 * transaction if needed. 251 * 252 */ 253 static int journal_finish_inode_data_buffers(journal_t *journal, 254 transaction_t *commit_transaction) 255 { 256 struct jbd2_inode *jinode, *next_i; 257 int err, ret = 0; 258 259 /* For locking, see the comment in journal_submit_data_buffers() */ 260 spin_lock(&journal->j_list_lock); 261 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 262 if (!(jinode->i_flags & JI_WAIT_DATA)) 263 continue; 264 jinode->i_flags |= JI_COMMIT_RUNNING; 265 spin_unlock(&journal->j_list_lock); 266 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping); 267 if (err) { 268 /* 269 * Because AS_EIO is cleared by 270 * filemap_fdatawait_range(), set it again so 271 * that user process can get -EIO from fsync(). 272 */ 273 mapping_set_error(jinode->i_vfs_inode->i_mapping, -EIO); 274 275 if (!ret) 276 ret = err; 277 } 278 spin_lock(&journal->j_list_lock); 279 jinode->i_flags &= ~JI_COMMIT_RUNNING; 280 smp_mb(); 281 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 282 } 283 284 /* Now refile inode to proper lists */ 285 list_for_each_entry_safe(jinode, next_i, 286 &commit_transaction->t_inode_list, i_list) { 287 list_del(&jinode->i_list); 288 if (jinode->i_next_transaction) { 289 jinode->i_transaction = jinode->i_next_transaction; 290 jinode->i_next_transaction = NULL; 291 list_add(&jinode->i_list, 292 &jinode->i_transaction->t_inode_list); 293 } else { 294 jinode->i_transaction = NULL; 295 } 296 } 297 spin_unlock(&journal->j_list_lock); 298 299 return ret; 300 } 301 302 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh) 303 { 304 struct page *page = bh->b_page; 305 char *addr; 306 __u32 checksum; 307 308 addr = kmap_atomic(page); 309 checksum = crc32_be(crc32_sum, 310 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size); 311 kunmap_atomic(addr); 312 313 return checksum; 314 } 315 316 static void write_tag_block(journal_t *j, journal_block_tag_t *tag, 317 unsigned long long block) 318 { 319 tag->t_blocknr = cpu_to_be32(block & (u32)~0); 320 if (jbd2_has_feature_64bit(j)) 321 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1); 322 } 323 324 static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag, 325 struct buffer_head *bh, __u32 sequence) 326 { 327 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag; 328 struct page *page = bh->b_page; 329 __u8 *addr; 330 __u32 csum32; 331 __be32 seq; 332 333 if (!jbd2_journal_has_csum_v2or3(j)) 334 return; 335 336 seq = cpu_to_be32(sequence); 337 addr = kmap_atomic(page); 338 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq)); 339 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data), 340 bh->b_size); 341 kunmap_atomic(addr); 342 343 if (jbd2_has_feature_csum3(j)) 344 tag3->t_checksum = cpu_to_be32(csum32); 345 else 346 tag->t_checksum = cpu_to_be16(csum32); 347 } 348 /* 349 * jbd2_journal_commit_transaction 350 * 351 * The primary function for committing a transaction to the log. This 352 * function is called by the journal thread to begin a complete commit. 353 */ 354 void jbd2_journal_commit_transaction(journal_t *journal) 355 { 356 struct transaction_stats_s stats; 357 transaction_t *commit_transaction; 358 struct journal_head *jh; 359 struct buffer_head *descriptor; 360 struct buffer_head **wbuf = journal->j_wbuf; 361 int bufs; 362 int flags; 363 int err; 364 unsigned long long blocknr; 365 ktime_t start_time; 366 u64 commit_time; 367 char *tagp = NULL; 368 journal_block_tag_t *tag = NULL; 369 int space_left = 0; 370 int first_tag = 0; 371 int tag_flag; 372 int i; 373 int tag_bytes = journal_tag_bytes(journal); 374 struct buffer_head *cbh = NULL; /* For transactional checksums */ 375 __u32 crc32_sum = ~0; 376 struct blk_plug plug; 377 /* Tail of the journal */ 378 unsigned long first_block; 379 tid_t first_tid; 380 int update_tail; 381 int csum_size = 0; 382 LIST_HEAD(io_bufs); 383 LIST_HEAD(log_bufs); 384 385 if (jbd2_journal_has_csum_v2or3(journal)) 386 csum_size = sizeof(struct jbd2_journal_block_tail); 387 388 /* 389 * First job: lock down the current transaction and wait for 390 * all outstanding updates to complete. 391 */ 392 393 /* Do we need to erase the effects of a prior jbd2_journal_flush? */ 394 if (journal->j_flags & JBD2_FLUSHED) { 395 jbd_debug(3, "super block updated\n"); 396 mutex_lock_io(&journal->j_checkpoint_mutex); 397 /* 398 * We hold j_checkpoint_mutex so tail cannot change under us. 399 * We don't need any special data guarantees for writing sb 400 * since journal is empty and it is ok for write to be 401 * flushed only with transaction commit. 402 */ 403 jbd2_journal_update_sb_log_tail(journal, 404 journal->j_tail_sequence, 405 journal->j_tail, 406 REQ_SYNC); 407 mutex_unlock(&journal->j_checkpoint_mutex); 408 } else { 409 jbd_debug(3, "superblock not updated\n"); 410 } 411 412 J_ASSERT(journal->j_running_transaction != NULL); 413 J_ASSERT(journal->j_committing_transaction == NULL); 414 415 commit_transaction = journal->j_running_transaction; 416 417 trace_jbd2_start_commit(journal, commit_transaction); 418 jbd_debug(1, "JBD2: starting commit of transaction %d\n", 419 commit_transaction->t_tid); 420 421 write_lock(&journal->j_state_lock); 422 J_ASSERT(commit_transaction->t_state == T_RUNNING); 423 commit_transaction->t_state = T_LOCKED; 424 425 trace_jbd2_commit_locking(journal, commit_transaction); 426 stats.run.rs_wait = commit_transaction->t_max_wait; 427 stats.run.rs_request_delay = 0; 428 stats.run.rs_locked = jiffies; 429 if (commit_transaction->t_requested) 430 stats.run.rs_request_delay = 431 jbd2_time_diff(commit_transaction->t_requested, 432 stats.run.rs_locked); 433 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start, 434 stats.run.rs_locked); 435 436 spin_lock(&commit_transaction->t_handle_lock); 437 while (atomic_read(&commit_transaction->t_updates)) { 438 DEFINE_WAIT(wait); 439 440 prepare_to_wait(&journal->j_wait_updates, &wait, 441 TASK_UNINTERRUPTIBLE); 442 if (atomic_read(&commit_transaction->t_updates)) { 443 spin_unlock(&commit_transaction->t_handle_lock); 444 write_unlock(&journal->j_state_lock); 445 schedule(); 446 write_lock(&journal->j_state_lock); 447 spin_lock(&commit_transaction->t_handle_lock); 448 } 449 finish_wait(&journal->j_wait_updates, &wait); 450 } 451 spin_unlock(&commit_transaction->t_handle_lock); 452 453 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <= 454 journal->j_max_transaction_buffers); 455 456 /* 457 * First thing we are allowed to do is to discard any remaining 458 * BJ_Reserved buffers. Note, it is _not_ permissible to assume 459 * that there are no such buffers: if a large filesystem 460 * operation like a truncate needs to split itself over multiple 461 * transactions, then it may try to do a jbd2_journal_restart() while 462 * there are still BJ_Reserved buffers outstanding. These must 463 * be released cleanly from the current transaction. 464 * 465 * In this case, the filesystem must still reserve write access 466 * again before modifying the buffer in the new transaction, but 467 * we do not require it to remember exactly which old buffers it 468 * has reserved. This is consistent with the existing behaviour 469 * that multiple jbd2_journal_get_write_access() calls to the same 470 * buffer are perfectly permissible. 471 */ 472 while (commit_transaction->t_reserved_list) { 473 jh = commit_transaction->t_reserved_list; 474 JBUFFER_TRACE(jh, "reserved, unused: refile"); 475 /* 476 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may 477 * leave undo-committed data. 478 */ 479 if (jh->b_committed_data) { 480 struct buffer_head *bh = jh2bh(jh); 481 482 jbd_lock_bh_state(bh); 483 jbd2_free(jh->b_committed_data, bh->b_size); 484 jh->b_committed_data = NULL; 485 jbd_unlock_bh_state(bh); 486 } 487 jbd2_journal_refile_buffer(journal, jh); 488 } 489 490 /* 491 * Now try to drop any written-back buffers from the journal's 492 * checkpoint lists. We do this *before* commit because it potentially 493 * frees some memory 494 */ 495 spin_lock(&journal->j_list_lock); 496 __jbd2_journal_clean_checkpoint_list(journal, false); 497 spin_unlock(&journal->j_list_lock); 498 499 jbd_debug(3, "JBD2: commit phase 1\n"); 500 501 /* 502 * Clear revoked flag to reflect there is no revoked buffers 503 * in the next transaction which is going to be started. 504 */ 505 jbd2_clear_buffer_revoked_flags(journal); 506 507 /* 508 * Switch to a new revoke table. 509 */ 510 jbd2_journal_switch_revoke_table(journal); 511 512 /* 513 * Reserved credits cannot be claimed anymore, free them 514 */ 515 atomic_sub(atomic_read(&journal->j_reserved_credits), 516 &commit_transaction->t_outstanding_credits); 517 518 trace_jbd2_commit_flushing(journal, commit_transaction); 519 stats.run.rs_flushing = jiffies; 520 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked, 521 stats.run.rs_flushing); 522 523 commit_transaction->t_state = T_FLUSH; 524 journal->j_committing_transaction = commit_transaction; 525 journal->j_running_transaction = NULL; 526 start_time = ktime_get(); 527 commit_transaction->t_log_start = journal->j_head; 528 wake_up(&journal->j_wait_transaction_locked); 529 write_unlock(&journal->j_state_lock); 530 531 jbd_debug(3, "JBD2: commit phase 2a\n"); 532 533 /* 534 * Now start flushing things to disk, in the order they appear 535 * on the transaction lists. Data blocks go first. 536 */ 537 err = journal_submit_data_buffers(journal, commit_transaction); 538 if (err) 539 jbd2_journal_abort(journal, err); 540 541 blk_start_plug(&plug); 542 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs); 543 544 jbd_debug(3, "JBD2: commit phase 2b\n"); 545 546 /* 547 * Way to go: we have now written out all of the data for a 548 * transaction! Now comes the tricky part: we need to write out 549 * metadata. Loop over the transaction's entire buffer list: 550 */ 551 write_lock(&journal->j_state_lock); 552 commit_transaction->t_state = T_COMMIT; 553 write_unlock(&journal->j_state_lock); 554 555 trace_jbd2_commit_logging(journal, commit_transaction); 556 stats.run.rs_logging = jiffies; 557 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing, 558 stats.run.rs_logging); 559 stats.run.rs_blocks = 560 atomic_read(&commit_transaction->t_outstanding_credits); 561 stats.run.rs_blocks_logged = 0; 562 563 J_ASSERT(commit_transaction->t_nr_buffers <= 564 atomic_read(&commit_transaction->t_outstanding_credits)); 565 566 err = 0; 567 bufs = 0; 568 descriptor = NULL; 569 while (commit_transaction->t_buffers) { 570 571 /* Find the next buffer to be journaled... */ 572 573 jh = commit_transaction->t_buffers; 574 575 /* If we're in abort mode, we just un-journal the buffer and 576 release it. */ 577 578 if (is_journal_aborted(journal)) { 579 clear_buffer_jbddirty(jh2bh(jh)); 580 JBUFFER_TRACE(jh, "journal is aborting: refile"); 581 jbd2_buffer_abort_trigger(jh, 582 jh->b_frozen_data ? 583 jh->b_frozen_triggers : 584 jh->b_triggers); 585 jbd2_journal_refile_buffer(journal, jh); 586 /* If that was the last one, we need to clean up 587 * any descriptor buffers which may have been 588 * already allocated, even if we are now 589 * aborting. */ 590 if (!commit_transaction->t_buffers) 591 goto start_journal_io; 592 continue; 593 } 594 595 /* Make sure we have a descriptor block in which to 596 record the metadata buffer. */ 597 598 if (!descriptor) { 599 J_ASSERT (bufs == 0); 600 601 jbd_debug(4, "JBD2: get descriptor\n"); 602 603 descriptor = jbd2_journal_get_descriptor_buffer( 604 commit_transaction, 605 JBD2_DESCRIPTOR_BLOCK); 606 if (!descriptor) { 607 jbd2_journal_abort(journal, -EIO); 608 continue; 609 } 610 611 jbd_debug(4, "JBD2: got buffer %llu (%p)\n", 612 (unsigned long long)descriptor->b_blocknr, 613 descriptor->b_data); 614 tagp = &descriptor->b_data[sizeof(journal_header_t)]; 615 space_left = descriptor->b_size - 616 sizeof(journal_header_t); 617 first_tag = 1; 618 set_buffer_jwrite(descriptor); 619 set_buffer_dirty(descriptor); 620 wbuf[bufs++] = descriptor; 621 622 /* Record it so that we can wait for IO 623 completion later */ 624 BUFFER_TRACE(descriptor, "ph3: file as descriptor"); 625 jbd2_file_log_bh(&log_bufs, descriptor); 626 } 627 628 /* Where is the buffer to be written? */ 629 630 err = jbd2_journal_next_log_block(journal, &blocknr); 631 /* If the block mapping failed, just abandon the buffer 632 and repeat this loop: we'll fall into the 633 refile-on-abort condition above. */ 634 if (err) { 635 jbd2_journal_abort(journal, err); 636 continue; 637 } 638 639 /* 640 * start_this_handle() uses t_outstanding_credits to determine 641 * the free space in the log, but this counter is changed 642 * by jbd2_journal_next_log_block() also. 643 */ 644 atomic_dec(&commit_transaction->t_outstanding_credits); 645 646 /* Bump b_count to prevent truncate from stumbling over 647 the shadowed buffer! @@@ This can go if we ever get 648 rid of the shadow pairing of buffers. */ 649 atomic_inc(&jh2bh(jh)->b_count); 650 651 /* 652 * Make a temporary IO buffer with which to write it out 653 * (this will requeue the metadata buffer to BJ_Shadow). 654 */ 655 set_bit(BH_JWrite, &jh2bh(jh)->b_state); 656 JBUFFER_TRACE(jh, "ph3: write metadata"); 657 flags = jbd2_journal_write_metadata_buffer(commit_transaction, 658 jh, &wbuf[bufs], blocknr); 659 if (flags < 0) { 660 jbd2_journal_abort(journal, flags); 661 continue; 662 } 663 jbd2_file_log_bh(&io_bufs, wbuf[bufs]); 664 665 /* Record the new block's tag in the current descriptor 666 buffer */ 667 668 tag_flag = 0; 669 if (flags & 1) 670 tag_flag |= JBD2_FLAG_ESCAPE; 671 if (!first_tag) 672 tag_flag |= JBD2_FLAG_SAME_UUID; 673 674 tag = (journal_block_tag_t *) tagp; 675 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr); 676 tag->t_flags = cpu_to_be16(tag_flag); 677 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs], 678 commit_transaction->t_tid); 679 tagp += tag_bytes; 680 space_left -= tag_bytes; 681 bufs++; 682 683 if (first_tag) { 684 memcpy (tagp, journal->j_uuid, 16); 685 tagp += 16; 686 space_left -= 16; 687 first_tag = 0; 688 } 689 690 /* If there's no more to do, or if the descriptor is full, 691 let the IO rip! */ 692 693 if (bufs == journal->j_wbufsize || 694 commit_transaction->t_buffers == NULL || 695 space_left < tag_bytes + 16 + csum_size) { 696 697 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs); 698 699 /* Write an end-of-descriptor marker before 700 submitting the IOs. "tag" still points to 701 the last tag we set up. */ 702 703 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG); 704 705 jbd2_descriptor_block_csum_set(journal, descriptor); 706 start_journal_io: 707 for (i = 0; i < bufs; i++) { 708 struct buffer_head *bh = wbuf[i]; 709 /* 710 * Compute checksum. 711 */ 712 if (jbd2_has_feature_checksum(journal)) { 713 crc32_sum = 714 jbd2_checksum_data(crc32_sum, bh); 715 } 716 717 lock_buffer(bh); 718 clear_buffer_dirty(bh); 719 set_buffer_uptodate(bh); 720 bh->b_end_io = journal_end_buffer_io_sync; 721 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh); 722 } 723 cond_resched(); 724 stats.run.rs_blocks_logged += bufs; 725 726 /* Force a new descriptor to be generated next 727 time round the loop. */ 728 descriptor = NULL; 729 bufs = 0; 730 } 731 } 732 733 err = journal_finish_inode_data_buffers(journal, commit_transaction); 734 if (err) { 735 printk(KERN_WARNING 736 "JBD2: Detected IO errors while flushing file data " 737 "on %s\n", journal->j_devname); 738 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR) 739 jbd2_journal_abort(journal, err); 740 err = 0; 741 } 742 743 /* 744 * Get current oldest transaction in the log before we issue flush 745 * to the filesystem device. After the flush we can be sure that 746 * blocks of all older transactions are checkpointed to persistent 747 * storage and we will be safe to update journal start in the 748 * superblock with the numbers we get here. 749 */ 750 update_tail = 751 jbd2_journal_get_log_tail(journal, &first_tid, &first_block); 752 753 write_lock(&journal->j_state_lock); 754 if (update_tail) { 755 long freed = first_block - journal->j_tail; 756 757 if (first_block < journal->j_tail) 758 freed += journal->j_last - journal->j_first; 759 /* Update tail only if we free significant amount of space */ 760 if (freed < journal->j_maxlen / 4) 761 update_tail = 0; 762 } 763 J_ASSERT(commit_transaction->t_state == T_COMMIT); 764 commit_transaction->t_state = T_COMMIT_DFLUSH; 765 write_unlock(&journal->j_state_lock); 766 767 /* 768 * If the journal is not located on the file system device, 769 * then we must flush the file system device before we issue 770 * the commit record 771 */ 772 if (commit_transaction->t_need_data_flush && 773 (journal->j_fs_dev != journal->j_dev) && 774 (journal->j_flags & JBD2_BARRIER)) 775 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL); 776 777 /* Done it all: now write the commit record asynchronously. */ 778 if (jbd2_has_feature_async_commit(journal)) { 779 err = journal_submit_commit_record(journal, commit_transaction, 780 &cbh, crc32_sum); 781 if (err) 782 __jbd2_journal_abort_hard(journal); 783 } 784 785 blk_finish_plug(&plug); 786 787 /* Lo and behold: we have just managed to send a transaction to 788 the log. Before we can commit it, wait for the IO so far to 789 complete. Control buffers being written are on the 790 transaction's t_log_list queue, and metadata buffers are on 791 the io_bufs list. 792 793 Wait for the buffers in reverse order. That way we are 794 less likely to be woken up until all IOs have completed, and 795 so we incur less scheduling load. 796 */ 797 798 jbd_debug(3, "JBD2: commit phase 3\n"); 799 800 while (!list_empty(&io_bufs)) { 801 struct buffer_head *bh = list_entry(io_bufs.prev, 802 struct buffer_head, 803 b_assoc_buffers); 804 805 wait_on_buffer(bh); 806 cond_resched(); 807 808 if (unlikely(!buffer_uptodate(bh))) 809 err = -EIO; 810 jbd2_unfile_log_bh(bh); 811 812 /* 813 * The list contains temporary buffer heads created by 814 * jbd2_journal_write_metadata_buffer(). 815 */ 816 BUFFER_TRACE(bh, "dumping temporary bh"); 817 __brelse(bh); 818 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); 819 free_buffer_head(bh); 820 821 /* We also have to refile the corresponding shadowed buffer */ 822 jh = commit_transaction->t_shadow_list->b_tprev; 823 bh = jh2bh(jh); 824 clear_buffer_jwrite(bh); 825 J_ASSERT_BH(bh, buffer_jbddirty(bh)); 826 J_ASSERT_BH(bh, !buffer_shadow(bh)); 827 828 /* The metadata is now released for reuse, but we need 829 to remember it against this transaction so that when 830 we finally commit, we can do any checkpointing 831 required. */ 832 JBUFFER_TRACE(jh, "file as BJ_Forget"); 833 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget); 834 JBUFFER_TRACE(jh, "brelse shadowed buffer"); 835 __brelse(bh); 836 } 837 838 J_ASSERT (commit_transaction->t_shadow_list == NULL); 839 840 jbd_debug(3, "JBD2: commit phase 4\n"); 841 842 /* Here we wait for the revoke record and descriptor record buffers */ 843 while (!list_empty(&log_bufs)) { 844 struct buffer_head *bh; 845 846 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers); 847 wait_on_buffer(bh); 848 cond_resched(); 849 850 if (unlikely(!buffer_uptodate(bh))) 851 err = -EIO; 852 853 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); 854 clear_buffer_jwrite(bh); 855 jbd2_unfile_log_bh(bh); 856 __brelse(bh); /* One for getblk */ 857 /* AKPM: bforget here */ 858 } 859 860 if (err) 861 jbd2_journal_abort(journal, err); 862 863 jbd_debug(3, "JBD2: commit phase 5\n"); 864 write_lock(&journal->j_state_lock); 865 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH); 866 commit_transaction->t_state = T_COMMIT_JFLUSH; 867 write_unlock(&journal->j_state_lock); 868 869 if (!jbd2_has_feature_async_commit(journal)) { 870 err = journal_submit_commit_record(journal, commit_transaction, 871 &cbh, crc32_sum); 872 if (err) 873 __jbd2_journal_abort_hard(journal); 874 } 875 if (cbh) 876 err = journal_wait_on_commit_record(journal, cbh); 877 if (jbd2_has_feature_async_commit(journal) && 878 journal->j_flags & JBD2_BARRIER) { 879 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL); 880 } 881 882 if (err) 883 jbd2_journal_abort(journal, err); 884 885 /* 886 * Now disk caches for filesystem device are flushed so we are safe to 887 * erase checkpointed transactions from the log by updating journal 888 * superblock. 889 */ 890 if (update_tail) 891 jbd2_update_log_tail(journal, first_tid, first_block); 892 893 /* End of a transaction! Finally, we can do checkpoint 894 processing: any buffers committed as a result of this 895 transaction can be removed from any checkpoint list it was on 896 before. */ 897 898 jbd_debug(3, "JBD2: commit phase 6\n"); 899 900 J_ASSERT(list_empty(&commit_transaction->t_inode_list)); 901 J_ASSERT(commit_transaction->t_buffers == NULL); 902 J_ASSERT(commit_transaction->t_checkpoint_list == NULL); 903 J_ASSERT(commit_transaction->t_shadow_list == NULL); 904 905 restart_loop: 906 /* 907 * As there are other places (journal_unmap_buffer()) adding buffers 908 * to this list we have to be careful and hold the j_list_lock. 909 */ 910 spin_lock(&journal->j_list_lock); 911 while (commit_transaction->t_forget) { 912 transaction_t *cp_transaction; 913 struct buffer_head *bh; 914 int try_to_free = 0; 915 916 jh = commit_transaction->t_forget; 917 spin_unlock(&journal->j_list_lock); 918 bh = jh2bh(jh); 919 /* 920 * Get a reference so that bh cannot be freed before we are 921 * done with it. 922 */ 923 get_bh(bh); 924 jbd_lock_bh_state(bh); 925 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction); 926 927 /* 928 * If there is undo-protected committed data against 929 * this buffer, then we can remove it now. If it is a 930 * buffer needing such protection, the old frozen_data 931 * field now points to a committed version of the 932 * buffer, so rotate that field to the new committed 933 * data. 934 * 935 * Otherwise, we can just throw away the frozen data now. 936 * 937 * We also know that the frozen data has already fired 938 * its triggers if they exist, so we can clear that too. 939 */ 940 if (jh->b_committed_data) { 941 jbd2_free(jh->b_committed_data, bh->b_size); 942 jh->b_committed_data = NULL; 943 if (jh->b_frozen_data) { 944 jh->b_committed_data = jh->b_frozen_data; 945 jh->b_frozen_data = NULL; 946 jh->b_frozen_triggers = NULL; 947 } 948 } else if (jh->b_frozen_data) { 949 jbd2_free(jh->b_frozen_data, bh->b_size); 950 jh->b_frozen_data = NULL; 951 jh->b_frozen_triggers = NULL; 952 } 953 954 spin_lock(&journal->j_list_lock); 955 cp_transaction = jh->b_cp_transaction; 956 if (cp_transaction) { 957 JBUFFER_TRACE(jh, "remove from old cp transaction"); 958 cp_transaction->t_chp_stats.cs_dropped++; 959 __jbd2_journal_remove_checkpoint(jh); 960 } 961 962 /* Only re-checkpoint the buffer_head if it is marked 963 * dirty. If the buffer was added to the BJ_Forget list 964 * by jbd2_journal_forget, it may no longer be dirty and 965 * there's no point in keeping a checkpoint record for 966 * it. */ 967 968 /* 969 * A buffer which has been freed while still being journaled by 970 * a previous transaction. 971 */ 972 if (buffer_freed(bh)) { 973 /* 974 * If the running transaction is the one containing 975 * "add to orphan" operation (b_next_transaction != 976 * NULL), we have to wait for that transaction to 977 * commit before we can really get rid of the buffer. 978 * So just clear b_modified to not confuse transaction 979 * credit accounting and refile the buffer to 980 * BJ_Forget of the running transaction. If the just 981 * committed transaction contains "add to orphan" 982 * operation, we can completely invalidate the buffer 983 * now. We are rather through in that since the 984 * buffer may be still accessible when blocksize < 985 * pagesize and it is attached to the last partial 986 * page. 987 */ 988 jh->b_modified = 0; 989 if (!jh->b_next_transaction) { 990 clear_buffer_freed(bh); 991 clear_buffer_jbddirty(bh); 992 clear_buffer_mapped(bh); 993 clear_buffer_new(bh); 994 clear_buffer_req(bh); 995 bh->b_bdev = NULL; 996 } 997 } 998 999 if (buffer_jbddirty(bh)) { 1000 JBUFFER_TRACE(jh, "add to new checkpointing trans"); 1001 __jbd2_journal_insert_checkpoint(jh, commit_transaction); 1002 if (is_journal_aborted(journal)) 1003 clear_buffer_jbddirty(bh); 1004 } else { 1005 J_ASSERT_BH(bh, !buffer_dirty(bh)); 1006 /* 1007 * The buffer on BJ_Forget list and not jbddirty means 1008 * it has been freed by this transaction and hence it 1009 * could not have been reallocated until this 1010 * transaction has committed. *BUT* it could be 1011 * reallocated once we have written all the data to 1012 * disk and before we process the buffer on BJ_Forget 1013 * list. 1014 */ 1015 if (!jh->b_next_transaction) 1016 try_to_free = 1; 1017 } 1018 JBUFFER_TRACE(jh, "refile or unfile buffer"); 1019 __jbd2_journal_refile_buffer(jh); 1020 jbd_unlock_bh_state(bh); 1021 if (try_to_free) 1022 release_buffer_page(bh); /* Drops bh reference */ 1023 else 1024 __brelse(bh); 1025 cond_resched_lock(&journal->j_list_lock); 1026 } 1027 spin_unlock(&journal->j_list_lock); 1028 /* 1029 * This is a bit sleazy. We use j_list_lock to protect transition 1030 * of a transaction into T_FINISHED state and calling 1031 * __jbd2_journal_drop_transaction(). Otherwise we could race with 1032 * other checkpointing code processing the transaction... 1033 */ 1034 write_lock(&journal->j_state_lock); 1035 spin_lock(&journal->j_list_lock); 1036 /* 1037 * Now recheck if some buffers did not get attached to the transaction 1038 * while the lock was dropped... 1039 */ 1040 if (commit_transaction->t_forget) { 1041 spin_unlock(&journal->j_list_lock); 1042 write_unlock(&journal->j_state_lock); 1043 goto restart_loop; 1044 } 1045 1046 /* Add the transaction to the checkpoint list 1047 * __journal_remove_checkpoint() can not destroy transaction 1048 * under us because it is not marked as T_FINISHED yet */ 1049 if (journal->j_checkpoint_transactions == NULL) { 1050 journal->j_checkpoint_transactions = commit_transaction; 1051 commit_transaction->t_cpnext = commit_transaction; 1052 commit_transaction->t_cpprev = commit_transaction; 1053 } else { 1054 commit_transaction->t_cpnext = 1055 journal->j_checkpoint_transactions; 1056 commit_transaction->t_cpprev = 1057 commit_transaction->t_cpnext->t_cpprev; 1058 commit_transaction->t_cpnext->t_cpprev = 1059 commit_transaction; 1060 commit_transaction->t_cpprev->t_cpnext = 1061 commit_transaction; 1062 } 1063 spin_unlock(&journal->j_list_lock); 1064 1065 /* Done with this transaction! */ 1066 1067 jbd_debug(3, "JBD2: commit phase 7\n"); 1068 1069 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH); 1070 1071 commit_transaction->t_start = jiffies; 1072 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging, 1073 commit_transaction->t_start); 1074 1075 /* 1076 * File the transaction statistics 1077 */ 1078 stats.ts_tid = commit_transaction->t_tid; 1079 stats.run.rs_handle_count = 1080 atomic_read(&commit_transaction->t_handle_count); 1081 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev, 1082 commit_transaction->t_tid, &stats.run); 1083 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0; 1084 1085 commit_transaction->t_state = T_COMMIT_CALLBACK; 1086 J_ASSERT(commit_transaction == journal->j_committing_transaction); 1087 journal->j_commit_sequence = commit_transaction->t_tid; 1088 journal->j_committing_transaction = NULL; 1089 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); 1090 1091 /* 1092 * weight the commit time higher than the average time so we don't 1093 * react too strongly to vast changes in the commit time 1094 */ 1095 if (likely(journal->j_average_commit_time)) 1096 journal->j_average_commit_time = (commit_time + 1097 journal->j_average_commit_time*3) / 4; 1098 else 1099 journal->j_average_commit_time = commit_time; 1100 1101 write_unlock(&journal->j_state_lock); 1102 1103 if (journal->j_commit_callback) 1104 journal->j_commit_callback(journal, commit_transaction); 1105 1106 trace_jbd2_end_commit(journal, commit_transaction); 1107 jbd_debug(1, "JBD2: commit %d complete, head %d\n", 1108 journal->j_commit_sequence, journal->j_tail_sequence); 1109 1110 write_lock(&journal->j_state_lock); 1111 spin_lock(&journal->j_list_lock); 1112 commit_transaction->t_state = T_FINISHED; 1113 /* Check if the transaction can be dropped now that we are finished */ 1114 if (commit_transaction->t_checkpoint_list == NULL && 1115 commit_transaction->t_checkpoint_io_list == NULL) { 1116 __jbd2_journal_drop_transaction(journal, commit_transaction); 1117 jbd2_journal_free_transaction(commit_transaction); 1118 } 1119 spin_unlock(&journal->j_list_lock); 1120 write_unlock(&journal->j_state_lock); 1121 wake_up(&journal->j_wait_done_commit); 1122 1123 /* 1124 * Calculate overall stats 1125 */ 1126 spin_lock(&journal->j_history_lock); 1127 journal->j_stats.ts_tid++; 1128 journal->j_stats.ts_requested += stats.ts_requested; 1129 journal->j_stats.run.rs_wait += stats.run.rs_wait; 1130 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay; 1131 journal->j_stats.run.rs_running += stats.run.rs_running; 1132 journal->j_stats.run.rs_locked += stats.run.rs_locked; 1133 journal->j_stats.run.rs_flushing += stats.run.rs_flushing; 1134 journal->j_stats.run.rs_logging += stats.run.rs_logging; 1135 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count; 1136 journal->j_stats.run.rs_blocks += stats.run.rs_blocks; 1137 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged; 1138 spin_unlock(&journal->j_history_lock); 1139 } 1140