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 #include <asm/system.h> 32 33 /* 34 * Default IO end handler for temporary BJ_IO buffer_heads. 35 */ 36 static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate) 37 { 38 BUFFER_TRACE(bh, ""); 39 if (uptodate) 40 set_buffer_uptodate(bh); 41 else 42 clear_buffer_uptodate(bh); 43 unlock_buffer(bh); 44 } 45 46 /* 47 * When an ext4 file is truncated, it is possible that some pages are not 48 * successfully freed, because they are attached to a committing transaction. 49 * After the transaction commits, these pages are left on the LRU, with no 50 * ->mapping, and with attached buffers. These pages are trivially reclaimable 51 * by the VM, but their apparent absence upsets the VM accounting, and it makes 52 * the numbers in /proc/meminfo look odd. 53 * 54 * So here, we have a buffer which has just come off the forget list. Look to 55 * see if we can strip all buffers from the backing page. 56 * 57 * Called under lock_journal(), and possibly under journal_datalist_lock. The 58 * caller provided us with a ref against the buffer, and we drop that here. 59 */ 60 static void release_buffer_page(struct buffer_head *bh) 61 { 62 struct page *page; 63 64 if (buffer_dirty(bh)) 65 goto nope; 66 if (atomic_read(&bh->b_count) != 1) 67 goto nope; 68 page = bh->b_page; 69 if (!page) 70 goto nope; 71 if (page->mapping) 72 goto nope; 73 74 /* OK, it's a truncated page */ 75 if (!trylock_page(page)) 76 goto nope; 77 78 page_cache_get(page); 79 __brelse(bh); 80 try_to_free_buffers(page); 81 unlock_page(page); 82 page_cache_release(page); 83 return; 84 85 nope: 86 __brelse(bh); 87 } 88 89 /* 90 * Done it all: now submit the commit record. We should have 91 * cleaned up our previous buffers by now, so if we are in abort 92 * mode we can now just skip the rest of the journal write 93 * entirely. 94 * 95 * Returns 1 if the journal needs to be aborted or 0 on success 96 */ 97 static int journal_submit_commit_record(journal_t *journal, 98 transaction_t *commit_transaction, 99 struct buffer_head **cbh, 100 __u32 crc32_sum) 101 { 102 struct journal_head *descriptor; 103 struct commit_header *tmp; 104 struct buffer_head *bh; 105 int ret; 106 struct timespec now = current_kernel_time(); 107 108 *cbh = NULL; 109 110 if (is_journal_aborted(journal)) 111 return 0; 112 113 descriptor = jbd2_journal_get_descriptor_buffer(journal); 114 if (!descriptor) 115 return 1; 116 117 bh = jh2bh(descriptor); 118 119 tmp = (struct commit_header *)bh->b_data; 120 tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); 121 tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK); 122 tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid); 123 tmp->h_commit_sec = cpu_to_be64(now.tv_sec); 124 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec); 125 126 if (JBD2_HAS_COMPAT_FEATURE(journal, 127 JBD2_FEATURE_COMPAT_CHECKSUM)) { 128 tmp->h_chksum_type = JBD2_CRC32_CHKSUM; 129 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE; 130 tmp->h_chksum[0] = cpu_to_be32(crc32_sum); 131 } 132 133 JBUFFER_TRACE(descriptor, "submit commit block"); 134 lock_buffer(bh); 135 clear_buffer_dirty(bh); 136 set_buffer_uptodate(bh); 137 bh->b_end_io = journal_end_buffer_io_sync; 138 139 if (journal->j_flags & JBD2_BARRIER && 140 !JBD2_HAS_INCOMPAT_FEATURE(journal, 141 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) 142 ret = submit_bh(WRITE_SYNC | WRITE_FLUSH_FUA, bh); 143 else 144 ret = submit_bh(WRITE_SYNC, bh); 145 146 *cbh = bh; 147 return ret; 148 } 149 150 /* 151 * This function along with journal_submit_commit_record 152 * allows to write the commit record asynchronously. 153 */ 154 static int journal_wait_on_commit_record(journal_t *journal, 155 struct buffer_head *bh) 156 { 157 int ret = 0; 158 159 clear_buffer_dirty(bh); 160 wait_on_buffer(bh); 161 162 if (unlikely(!buffer_uptodate(bh))) 163 ret = -EIO; 164 put_bh(bh); /* One for getblk() */ 165 jbd2_journal_put_journal_head(bh2jh(bh)); 166 167 return ret; 168 } 169 170 /* 171 * write the filemap data using writepage() address_space_operations. 172 * We don't do block allocation here even for delalloc. We don't 173 * use writepages() because with dealyed allocation we may be doing 174 * block allocation in writepages(). 175 */ 176 static int journal_submit_inode_data_buffers(struct address_space *mapping) 177 { 178 int ret; 179 struct writeback_control wbc = { 180 .sync_mode = WB_SYNC_ALL, 181 .nr_to_write = mapping->nrpages * 2, 182 .range_start = 0, 183 .range_end = i_size_read(mapping->host), 184 }; 185 186 ret = generic_writepages(mapping, &wbc); 187 return ret; 188 } 189 190 /* 191 * Submit all the data buffers of inode associated with the transaction to 192 * disk. 193 * 194 * We are in a committing transaction. Therefore no new inode can be added to 195 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently 196 * operate on from being released while we write out pages. 197 */ 198 static int journal_submit_data_buffers(journal_t *journal, 199 transaction_t *commit_transaction) 200 { 201 struct jbd2_inode *jinode; 202 int err, ret = 0; 203 struct address_space *mapping; 204 205 spin_lock(&journal->j_list_lock); 206 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 207 mapping = jinode->i_vfs_inode->i_mapping; 208 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 209 spin_unlock(&journal->j_list_lock); 210 /* 211 * submit the inode data buffers. We use writepage 212 * instead of writepages. Because writepages can do 213 * block allocation with delalloc. We need to write 214 * only allocated blocks here. 215 */ 216 trace_jbd2_submit_inode_data(jinode->i_vfs_inode); 217 err = journal_submit_inode_data_buffers(mapping); 218 if (!ret) 219 ret = err; 220 spin_lock(&journal->j_list_lock); 221 J_ASSERT(jinode->i_transaction == commit_transaction); 222 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 223 smp_mb__after_clear_bit(); 224 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 225 } 226 spin_unlock(&journal->j_list_lock); 227 return ret; 228 } 229 230 /* 231 * Wait for data submitted for writeout, refile inodes to proper 232 * transaction if needed. 233 * 234 */ 235 static int journal_finish_inode_data_buffers(journal_t *journal, 236 transaction_t *commit_transaction) 237 { 238 struct jbd2_inode *jinode, *next_i; 239 int err, ret = 0; 240 241 /* For locking, see the comment in journal_submit_data_buffers() */ 242 spin_lock(&journal->j_list_lock); 243 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 244 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 245 spin_unlock(&journal->j_list_lock); 246 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping); 247 if (err) { 248 /* 249 * Because AS_EIO is cleared by 250 * filemap_fdatawait_range(), set it again so 251 * that user process can get -EIO from fsync(). 252 */ 253 set_bit(AS_EIO, 254 &jinode->i_vfs_inode->i_mapping->flags); 255 256 if (!ret) 257 ret = err; 258 } 259 spin_lock(&journal->j_list_lock); 260 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 261 smp_mb__after_clear_bit(); 262 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 263 } 264 265 /* Now refile inode to proper lists */ 266 list_for_each_entry_safe(jinode, next_i, 267 &commit_transaction->t_inode_list, i_list) { 268 list_del(&jinode->i_list); 269 if (jinode->i_next_transaction) { 270 jinode->i_transaction = jinode->i_next_transaction; 271 jinode->i_next_transaction = NULL; 272 list_add(&jinode->i_list, 273 &jinode->i_transaction->t_inode_list); 274 } else { 275 jinode->i_transaction = NULL; 276 } 277 } 278 spin_unlock(&journal->j_list_lock); 279 280 return ret; 281 } 282 283 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh) 284 { 285 struct page *page = bh->b_page; 286 char *addr; 287 __u32 checksum; 288 289 addr = kmap_atomic(page, KM_USER0); 290 checksum = crc32_be(crc32_sum, 291 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size); 292 kunmap_atomic(addr, KM_USER0); 293 294 return checksum; 295 } 296 297 static void write_tag_block(int tag_bytes, journal_block_tag_t *tag, 298 unsigned long long block) 299 { 300 tag->t_blocknr = cpu_to_be32(block & (u32)~0); 301 if (tag_bytes > JBD2_TAG_SIZE32) 302 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1); 303 } 304 305 /* 306 * jbd2_journal_commit_transaction 307 * 308 * The primary function for committing a transaction to the log. This 309 * function is called by the journal thread to begin a complete commit. 310 */ 311 void jbd2_journal_commit_transaction(journal_t *journal) 312 { 313 struct transaction_stats_s stats; 314 transaction_t *commit_transaction; 315 struct journal_head *jh, *new_jh, *descriptor; 316 struct buffer_head **wbuf = journal->j_wbuf; 317 int bufs; 318 int flags; 319 int err; 320 unsigned long long blocknr; 321 ktime_t start_time; 322 u64 commit_time; 323 char *tagp = NULL; 324 journal_header_t *header; 325 journal_block_tag_t *tag = NULL; 326 int space_left = 0; 327 int first_tag = 0; 328 int tag_flag; 329 int i, to_free = 0; 330 int tag_bytes = journal_tag_bytes(journal); 331 struct buffer_head *cbh = NULL; /* For transactional checksums */ 332 __u32 crc32_sum = ~0; 333 struct blk_plug plug; 334 335 /* 336 * First job: lock down the current transaction and wait for 337 * all outstanding updates to complete. 338 */ 339 340 /* Do we need to erase the effects of a prior jbd2_journal_flush? */ 341 if (journal->j_flags & JBD2_FLUSHED) { 342 jbd_debug(3, "super block updated\n"); 343 jbd2_journal_update_superblock(journal, 1); 344 } else { 345 jbd_debug(3, "superblock not updated\n"); 346 } 347 348 J_ASSERT(journal->j_running_transaction != NULL); 349 J_ASSERT(journal->j_committing_transaction == NULL); 350 351 commit_transaction = journal->j_running_transaction; 352 J_ASSERT(commit_transaction->t_state == T_RUNNING); 353 354 trace_jbd2_start_commit(journal, commit_transaction); 355 jbd_debug(1, "JBD2: starting commit of transaction %d\n", 356 commit_transaction->t_tid); 357 358 write_lock(&journal->j_state_lock); 359 commit_transaction->t_state = T_LOCKED; 360 361 trace_jbd2_commit_locking(journal, commit_transaction); 362 stats.run.rs_wait = commit_transaction->t_max_wait; 363 stats.run.rs_locked = jiffies; 364 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start, 365 stats.run.rs_locked); 366 367 spin_lock(&commit_transaction->t_handle_lock); 368 while (atomic_read(&commit_transaction->t_updates)) { 369 DEFINE_WAIT(wait); 370 371 prepare_to_wait(&journal->j_wait_updates, &wait, 372 TASK_UNINTERRUPTIBLE); 373 if (atomic_read(&commit_transaction->t_updates)) { 374 spin_unlock(&commit_transaction->t_handle_lock); 375 write_unlock(&journal->j_state_lock); 376 schedule(); 377 write_lock(&journal->j_state_lock); 378 spin_lock(&commit_transaction->t_handle_lock); 379 } 380 finish_wait(&journal->j_wait_updates, &wait); 381 } 382 spin_unlock(&commit_transaction->t_handle_lock); 383 384 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <= 385 journal->j_max_transaction_buffers); 386 387 /* 388 * First thing we are allowed to do is to discard any remaining 389 * BJ_Reserved buffers. Note, it is _not_ permissible to assume 390 * that there are no such buffers: if a large filesystem 391 * operation like a truncate needs to split itself over multiple 392 * transactions, then it may try to do a jbd2_journal_restart() while 393 * there are still BJ_Reserved buffers outstanding. These must 394 * be released cleanly from the current transaction. 395 * 396 * In this case, the filesystem must still reserve write access 397 * again before modifying the buffer in the new transaction, but 398 * we do not require it to remember exactly which old buffers it 399 * has reserved. This is consistent with the existing behaviour 400 * that multiple jbd2_journal_get_write_access() calls to the same 401 * buffer are perfectly permissible. 402 */ 403 while (commit_transaction->t_reserved_list) { 404 jh = commit_transaction->t_reserved_list; 405 JBUFFER_TRACE(jh, "reserved, unused: refile"); 406 /* 407 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may 408 * leave undo-committed data. 409 */ 410 if (jh->b_committed_data) { 411 struct buffer_head *bh = jh2bh(jh); 412 413 jbd_lock_bh_state(bh); 414 jbd2_free(jh->b_committed_data, bh->b_size); 415 jh->b_committed_data = NULL; 416 jbd_unlock_bh_state(bh); 417 } 418 jbd2_journal_refile_buffer(journal, jh); 419 } 420 421 /* 422 * Now try to drop any written-back buffers from the journal's 423 * checkpoint lists. We do this *before* commit because it potentially 424 * frees some memory 425 */ 426 spin_lock(&journal->j_list_lock); 427 __jbd2_journal_clean_checkpoint_list(journal); 428 spin_unlock(&journal->j_list_lock); 429 430 jbd_debug(3, "JBD2: commit phase 1\n"); 431 432 /* 433 * Switch to a new revoke table. 434 */ 435 jbd2_journal_switch_revoke_table(journal); 436 437 trace_jbd2_commit_flushing(journal, commit_transaction); 438 stats.run.rs_flushing = jiffies; 439 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked, 440 stats.run.rs_flushing); 441 442 commit_transaction->t_state = T_FLUSH; 443 journal->j_committing_transaction = commit_transaction; 444 journal->j_running_transaction = NULL; 445 start_time = ktime_get(); 446 commit_transaction->t_log_start = journal->j_head; 447 wake_up(&journal->j_wait_transaction_locked); 448 write_unlock(&journal->j_state_lock); 449 450 jbd_debug(3, "JBD2: commit phase 2\n"); 451 452 /* 453 * Now start flushing things to disk, in the order they appear 454 * on the transaction lists. Data blocks go first. 455 */ 456 err = journal_submit_data_buffers(journal, commit_transaction); 457 if (err) 458 jbd2_journal_abort(journal, err); 459 460 blk_start_plug(&plug); 461 jbd2_journal_write_revoke_records(journal, commit_transaction, 462 WRITE_SYNC); 463 blk_finish_plug(&plug); 464 465 jbd_debug(3, "JBD2: commit phase 2\n"); 466 467 /* 468 * Way to go: we have now written out all of the data for a 469 * transaction! Now comes the tricky part: we need to write out 470 * metadata. Loop over the transaction's entire buffer list: 471 */ 472 write_lock(&journal->j_state_lock); 473 commit_transaction->t_state = T_COMMIT; 474 write_unlock(&journal->j_state_lock); 475 476 trace_jbd2_commit_logging(journal, commit_transaction); 477 stats.run.rs_logging = jiffies; 478 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing, 479 stats.run.rs_logging); 480 stats.run.rs_blocks = 481 atomic_read(&commit_transaction->t_outstanding_credits); 482 stats.run.rs_blocks_logged = 0; 483 484 J_ASSERT(commit_transaction->t_nr_buffers <= 485 atomic_read(&commit_transaction->t_outstanding_credits)); 486 487 err = 0; 488 descriptor = NULL; 489 bufs = 0; 490 blk_start_plug(&plug); 491 while (commit_transaction->t_buffers) { 492 493 /* Find the next buffer to be journaled... */ 494 495 jh = commit_transaction->t_buffers; 496 497 /* If we're in abort mode, we just un-journal the buffer and 498 release it. */ 499 500 if (is_journal_aborted(journal)) { 501 clear_buffer_jbddirty(jh2bh(jh)); 502 JBUFFER_TRACE(jh, "journal is aborting: refile"); 503 jbd2_buffer_abort_trigger(jh, 504 jh->b_frozen_data ? 505 jh->b_frozen_triggers : 506 jh->b_triggers); 507 jbd2_journal_refile_buffer(journal, jh); 508 /* If that was the last one, we need to clean up 509 * any descriptor buffers which may have been 510 * already allocated, even if we are now 511 * aborting. */ 512 if (!commit_transaction->t_buffers) 513 goto start_journal_io; 514 continue; 515 } 516 517 /* Make sure we have a descriptor block in which to 518 record the metadata buffer. */ 519 520 if (!descriptor) { 521 struct buffer_head *bh; 522 523 J_ASSERT (bufs == 0); 524 525 jbd_debug(4, "JBD2: get descriptor\n"); 526 527 descriptor = jbd2_journal_get_descriptor_buffer(journal); 528 if (!descriptor) { 529 jbd2_journal_abort(journal, -EIO); 530 continue; 531 } 532 533 bh = jh2bh(descriptor); 534 jbd_debug(4, "JBD2: got buffer %llu (%p)\n", 535 (unsigned long long)bh->b_blocknr, bh->b_data); 536 header = (journal_header_t *)&bh->b_data[0]; 537 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); 538 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK); 539 header->h_sequence = cpu_to_be32(commit_transaction->t_tid); 540 541 tagp = &bh->b_data[sizeof(journal_header_t)]; 542 space_left = bh->b_size - sizeof(journal_header_t); 543 first_tag = 1; 544 set_buffer_jwrite(bh); 545 set_buffer_dirty(bh); 546 wbuf[bufs++] = bh; 547 548 /* Record it so that we can wait for IO 549 completion later */ 550 BUFFER_TRACE(bh, "ph3: file as descriptor"); 551 jbd2_journal_file_buffer(descriptor, commit_transaction, 552 BJ_LogCtl); 553 } 554 555 /* Where is the buffer to be written? */ 556 557 err = jbd2_journal_next_log_block(journal, &blocknr); 558 /* If the block mapping failed, just abandon the buffer 559 and repeat this loop: we'll fall into the 560 refile-on-abort condition above. */ 561 if (err) { 562 jbd2_journal_abort(journal, err); 563 continue; 564 } 565 566 /* 567 * start_this_handle() uses t_outstanding_credits to determine 568 * the free space in the log, but this counter is changed 569 * by jbd2_journal_next_log_block() also. 570 */ 571 atomic_dec(&commit_transaction->t_outstanding_credits); 572 573 /* Bump b_count to prevent truncate from stumbling over 574 the shadowed buffer! @@@ This can go if we ever get 575 rid of the BJ_IO/BJ_Shadow pairing of buffers. */ 576 atomic_inc(&jh2bh(jh)->b_count); 577 578 /* Make a temporary IO buffer with which to write it out 579 (this will requeue both the metadata buffer and the 580 temporary IO buffer). new_bh goes on BJ_IO*/ 581 582 set_bit(BH_JWrite, &jh2bh(jh)->b_state); 583 /* 584 * akpm: jbd2_journal_write_metadata_buffer() sets 585 * new_bh->b_transaction to commit_transaction. 586 * We need to clean this up before we release new_bh 587 * (which is of type BJ_IO) 588 */ 589 JBUFFER_TRACE(jh, "ph3: write metadata"); 590 flags = jbd2_journal_write_metadata_buffer(commit_transaction, 591 jh, &new_jh, blocknr); 592 if (flags < 0) { 593 jbd2_journal_abort(journal, flags); 594 continue; 595 } 596 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state); 597 wbuf[bufs++] = jh2bh(new_jh); 598 599 /* Record the new block's tag in the current descriptor 600 buffer */ 601 602 tag_flag = 0; 603 if (flags & 1) 604 tag_flag |= JBD2_FLAG_ESCAPE; 605 if (!first_tag) 606 tag_flag |= JBD2_FLAG_SAME_UUID; 607 608 tag = (journal_block_tag_t *) tagp; 609 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr); 610 tag->t_flags = cpu_to_be32(tag_flag); 611 tagp += tag_bytes; 612 space_left -= tag_bytes; 613 614 if (first_tag) { 615 memcpy (tagp, journal->j_uuid, 16); 616 tagp += 16; 617 space_left -= 16; 618 first_tag = 0; 619 } 620 621 /* If there's no more to do, or if the descriptor is full, 622 let the IO rip! */ 623 624 if (bufs == journal->j_wbufsize || 625 commit_transaction->t_buffers == NULL || 626 space_left < tag_bytes + 16) { 627 628 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs); 629 630 /* Write an end-of-descriptor marker before 631 submitting the IOs. "tag" still points to 632 the last tag we set up. */ 633 634 tag->t_flags |= cpu_to_be32(JBD2_FLAG_LAST_TAG); 635 636 start_journal_io: 637 for (i = 0; i < bufs; i++) { 638 struct buffer_head *bh = wbuf[i]; 639 /* 640 * Compute checksum. 641 */ 642 if (JBD2_HAS_COMPAT_FEATURE(journal, 643 JBD2_FEATURE_COMPAT_CHECKSUM)) { 644 crc32_sum = 645 jbd2_checksum_data(crc32_sum, bh); 646 } 647 648 lock_buffer(bh); 649 clear_buffer_dirty(bh); 650 set_buffer_uptodate(bh); 651 bh->b_end_io = journal_end_buffer_io_sync; 652 submit_bh(WRITE_SYNC, bh); 653 } 654 cond_resched(); 655 stats.run.rs_blocks_logged += bufs; 656 657 /* Force a new descriptor to be generated next 658 time round the loop. */ 659 descriptor = NULL; 660 bufs = 0; 661 } 662 } 663 664 err = journal_finish_inode_data_buffers(journal, commit_transaction); 665 if (err) { 666 printk(KERN_WARNING 667 "JBD2: Detected IO errors while flushing file data " 668 "on %s\n", journal->j_devname); 669 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR) 670 jbd2_journal_abort(journal, err); 671 err = 0; 672 } 673 674 write_lock(&journal->j_state_lock); 675 J_ASSERT(commit_transaction->t_state == T_COMMIT); 676 commit_transaction->t_state = T_COMMIT_DFLUSH; 677 write_unlock(&journal->j_state_lock); 678 /* 679 * If the journal is not located on the file system device, 680 * then we must flush the file system device before we issue 681 * the commit record 682 */ 683 if (commit_transaction->t_need_data_flush && 684 (journal->j_fs_dev != journal->j_dev) && 685 (journal->j_flags & JBD2_BARRIER)) 686 blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL); 687 688 /* Done it all: now write the commit record asynchronously. */ 689 if (JBD2_HAS_INCOMPAT_FEATURE(journal, 690 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 691 err = journal_submit_commit_record(journal, commit_transaction, 692 &cbh, crc32_sum); 693 if (err) 694 __jbd2_journal_abort_hard(journal); 695 } 696 697 blk_finish_plug(&plug); 698 699 /* Lo and behold: we have just managed to send a transaction to 700 the log. Before we can commit it, wait for the IO so far to 701 complete. Control buffers being written are on the 702 transaction's t_log_list queue, and metadata buffers are on 703 the t_iobuf_list queue. 704 705 Wait for the buffers in reverse order. That way we are 706 less likely to be woken up until all IOs have completed, and 707 so we incur less scheduling load. 708 */ 709 710 jbd_debug(3, "JBD2: commit phase 3\n"); 711 712 /* 713 * akpm: these are BJ_IO, and j_list_lock is not needed. 714 * See __journal_try_to_free_buffer. 715 */ 716 wait_for_iobuf: 717 while (commit_transaction->t_iobuf_list != NULL) { 718 struct buffer_head *bh; 719 720 jh = commit_transaction->t_iobuf_list->b_tprev; 721 bh = jh2bh(jh); 722 if (buffer_locked(bh)) { 723 wait_on_buffer(bh); 724 goto wait_for_iobuf; 725 } 726 if (cond_resched()) 727 goto wait_for_iobuf; 728 729 if (unlikely(!buffer_uptodate(bh))) 730 err = -EIO; 731 732 clear_buffer_jwrite(bh); 733 734 JBUFFER_TRACE(jh, "ph4: unfile after journal write"); 735 jbd2_journal_unfile_buffer(journal, jh); 736 737 /* 738 * ->t_iobuf_list should contain only dummy buffer_heads 739 * which were created by jbd2_journal_write_metadata_buffer(). 740 */ 741 BUFFER_TRACE(bh, "dumping temporary bh"); 742 jbd2_journal_put_journal_head(jh); 743 __brelse(bh); 744 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); 745 free_buffer_head(bh); 746 747 /* We also have to unlock and free the corresponding 748 shadowed buffer */ 749 jh = commit_transaction->t_shadow_list->b_tprev; 750 bh = jh2bh(jh); 751 clear_bit(BH_JWrite, &bh->b_state); 752 J_ASSERT_BH(bh, buffer_jbddirty(bh)); 753 754 /* The metadata is now released for reuse, but we need 755 to remember it against this transaction so that when 756 we finally commit, we can do any checkpointing 757 required. */ 758 JBUFFER_TRACE(jh, "file as BJ_Forget"); 759 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget); 760 /* 761 * Wake up any transactions which were waiting for this IO to 762 * complete. The barrier must be here so that changes by 763 * jbd2_journal_file_buffer() take effect before wake_up_bit() 764 * does the waitqueue check. 765 */ 766 smp_mb(); 767 wake_up_bit(&bh->b_state, BH_Unshadow); 768 JBUFFER_TRACE(jh, "brelse shadowed buffer"); 769 __brelse(bh); 770 } 771 772 J_ASSERT (commit_transaction->t_shadow_list == NULL); 773 774 jbd_debug(3, "JBD2: commit phase 4\n"); 775 776 /* Here we wait for the revoke record and descriptor record buffers */ 777 wait_for_ctlbuf: 778 while (commit_transaction->t_log_list != NULL) { 779 struct buffer_head *bh; 780 781 jh = commit_transaction->t_log_list->b_tprev; 782 bh = jh2bh(jh); 783 if (buffer_locked(bh)) { 784 wait_on_buffer(bh); 785 goto wait_for_ctlbuf; 786 } 787 if (cond_resched()) 788 goto wait_for_ctlbuf; 789 790 if (unlikely(!buffer_uptodate(bh))) 791 err = -EIO; 792 793 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); 794 clear_buffer_jwrite(bh); 795 jbd2_journal_unfile_buffer(journal, jh); 796 jbd2_journal_put_journal_head(jh); 797 __brelse(bh); /* One for getblk */ 798 /* AKPM: bforget here */ 799 } 800 801 if (err) 802 jbd2_journal_abort(journal, err); 803 804 jbd_debug(3, "JBD2: commit phase 5\n"); 805 write_lock(&journal->j_state_lock); 806 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH); 807 commit_transaction->t_state = T_COMMIT_JFLUSH; 808 write_unlock(&journal->j_state_lock); 809 810 if (!JBD2_HAS_INCOMPAT_FEATURE(journal, 811 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 812 err = journal_submit_commit_record(journal, commit_transaction, 813 &cbh, crc32_sum); 814 if (err) 815 __jbd2_journal_abort_hard(journal); 816 } 817 if (cbh) 818 err = journal_wait_on_commit_record(journal, cbh); 819 if (JBD2_HAS_INCOMPAT_FEATURE(journal, 820 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) && 821 journal->j_flags & JBD2_BARRIER) { 822 blkdev_issue_flush(journal->j_dev, GFP_KERNEL, NULL); 823 } 824 825 if (err) 826 jbd2_journal_abort(journal, err); 827 828 /* End of a transaction! Finally, we can do checkpoint 829 processing: any buffers committed as a result of this 830 transaction can be removed from any checkpoint list it was on 831 before. */ 832 833 jbd_debug(3, "JBD2: commit phase 6\n"); 834 835 J_ASSERT(list_empty(&commit_transaction->t_inode_list)); 836 J_ASSERT(commit_transaction->t_buffers == NULL); 837 J_ASSERT(commit_transaction->t_checkpoint_list == NULL); 838 J_ASSERT(commit_transaction->t_iobuf_list == NULL); 839 J_ASSERT(commit_transaction->t_shadow_list == NULL); 840 J_ASSERT(commit_transaction->t_log_list == NULL); 841 842 restart_loop: 843 /* 844 * As there are other places (journal_unmap_buffer()) adding buffers 845 * to this list we have to be careful and hold the j_list_lock. 846 */ 847 spin_lock(&journal->j_list_lock); 848 while (commit_transaction->t_forget) { 849 transaction_t *cp_transaction; 850 struct buffer_head *bh; 851 int try_to_free = 0; 852 853 jh = commit_transaction->t_forget; 854 spin_unlock(&journal->j_list_lock); 855 bh = jh2bh(jh); 856 /* 857 * Get a reference so that bh cannot be freed before we are 858 * done with it. 859 */ 860 get_bh(bh); 861 jbd_lock_bh_state(bh); 862 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction); 863 864 /* 865 * If there is undo-protected committed data against 866 * this buffer, then we can remove it now. If it is a 867 * buffer needing such protection, the old frozen_data 868 * field now points to a committed version of the 869 * buffer, so rotate that field to the new committed 870 * data. 871 * 872 * Otherwise, we can just throw away the frozen data now. 873 * 874 * We also know that the frozen data has already fired 875 * its triggers if they exist, so we can clear that too. 876 */ 877 if (jh->b_committed_data) { 878 jbd2_free(jh->b_committed_data, bh->b_size); 879 jh->b_committed_data = NULL; 880 if (jh->b_frozen_data) { 881 jh->b_committed_data = jh->b_frozen_data; 882 jh->b_frozen_data = NULL; 883 jh->b_frozen_triggers = NULL; 884 } 885 } else if (jh->b_frozen_data) { 886 jbd2_free(jh->b_frozen_data, bh->b_size); 887 jh->b_frozen_data = NULL; 888 jh->b_frozen_triggers = NULL; 889 } 890 891 spin_lock(&journal->j_list_lock); 892 cp_transaction = jh->b_cp_transaction; 893 if (cp_transaction) { 894 JBUFFER_TRACE(jh, "remove from old cp transaction"); 895 cp_transaction->t_chp_stats.cs_dropped++; 896 __jbd2_journal_remove_checkpoint(jh); 897 } 898 899 /* Only re-checkpoint the buffer_head if it is marked 900 * dirty. If the buffer was added to the BJ_Forget list 901 * by jbd2_journal_forget, it may no longer be dirty and 902 * there's no point in keeping a checkpoint record for 903 * it. */ 904 905 /* A buffer which has been freed while still being 906 * journaled by a previous transaction may end up still 907 * being dirty here, but we want to avoid writing back 908 * that buffer in the future after the "add to orphan" 909 * operation been committed, That's not only a performance 910 * gain, it also stops aliasing problems if the buffer is 911 * left behind for writeback and gets reallocated for another 912 * use in a different page. */ 913 if (buffer_freed(bh) && !jh->b_next_transaction) { 914 clear_buffer_freed(bh); 915 clear_buffer_jbddirty(bh); 916 } 917 918 if (buffer_jbddirty(bh)) { 919 JBUFFER_TRACE(jh, "add to new checkpointing trans"); 920 __jbd2_journal_insert_checkpoint(jh, commit_transaction); 921 if (is_journal_aborted(journal)) 922 clear_buffer_jbddirty(bh); 923 } else { 924 J_ASSERT_BH(bh, !buffer_dirty(bh)); 925 /* 926 * The buffer on BJ_Forget list and not jbddirty means 927 * it has been freed by this transaction and hence it 928 * could not have been reallocated until this 929 * transaction has committed. *BUT* it could be 930 * reallocated once we have written all the data to 931 * disk and before we process the buffer on BJ_Forget 932 * list. 933 */ 934 if (!jh->b_next_transaction) 935 try_to_free = 1; 936 } 937 JBUFFER_TRACE(jh, "refile or unfile buffer"); 938 __jbd2_journal_refile_buffer(jh); 939 jbd_unlock_bh_state(bh); 940 if (try_to_free) 941 release_buffer_page(bh); /* Drops bh reference */ 942 else 943 __brelse(bh); 944 cond_resched_lock(&journal->j_list_lock); 945 } 946 spin_unlock(&journal->j_list_lock); 947 /* 948 * This is a bit sleazy. We use j_list_lock to protect transition 949 * of a transaction into T_FINISHED state and calling 950 * __jbd2_journal_drop_transaction(). Otherwise we could race with 951 * other checkpointing code processing the transaction... 952 */ 953 write_lock(&journal->j_state_lock); 954 spin_lock(&journal->j_list_lock); 955 /* 956 * Now recheck if some buffers did not get attached to the transaction 957 * while the lock was dropped... 958 */ 959 if (commit_transaction->t_forget) { 960 spin_unlock(&journal->j_list_lock); 961 write_unlock(&journal->j_state_lock); 962 goto restart_loop; 963 } 964 965 /* Done with this transaction! */ 966 967 jbd_debug(3, "JBD2: commit phase 7\n"); 968 969 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH); 970 971 commit_transaction->t_start = jiffies; 972 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging, 973 commit_transaction->t_start); 974 975 /* 976 * File the transaction statistics 977 */ 978 stats.ts_tid = commit_transaction->t_tid; 979 stats.run.rs_handle_count = 980 atomic_read(&commit_transaction->t_handle_count); 981 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev, 982 commit_transaction->t_tid, &stats.run); 983 984 /* 985 * Calculate overall stats 986 */ 987 spin_lock(&journal->j_history_lock); 988 journal->j_stats.ts_tid++; 989 journal->j_stats.run.rs_wait += stats.run.rs_wait; 990 journal->j_stats.run.rs_running += stats.run.rs_running; 991 journal->j_stats.run.rs_locked += stats.run.rs_locked; 992 journal->j_stats.run.rs_flushing += stats.run.rs_flushing; 993 journal->j_stats.run.rs_logging += stats.run.rs_logging; 994 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count; 995 journal->j_stats.run.rs_blocks += stats.run.rs_blocks; 996 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged; 997 spin_unlock(&journal->j_history_lock); 998 999 commit_transaction->t_state = T_FINISHED; 1000 J_ASSERT(commit_transaction == journal->j_committing_transaction); 1001 journal->j_commit_sequence = commit_transaction->t_tid; 1002 journal->j_committing_transaction = NULL; 1003 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); 1004 1005 /* 1006 * weight the commit time higher than the average time so we don't 1007 * react too strongly to vast changes in the commit time 1008 */ 1009 if (likely(journal->j_average_commit_time)) 1010 journal->j_average_commit_time = (commit_time + 1011 journal->j_average_commit_time*3) / 4; 1012 else 1013 journal->j_average_commit_time = commit_time; 1014 write_unlock(&journal->j_state_lock); 1015 1016 if (commit_transaction->t_checkpoint_list == NULL && 1017 commit_transaction->t_checkpoint_io_list == NULL) { 1018 __jbd2_journal_drop_transaction(journal, commit_transaction); 1019 to_free = 1; 1020 } else { 1021 if (journal->j_checkpoint_transactions == NULL) { 1022 journal->j_checkpoint_transactions = commit_transaction; 1023 commit_transaction->t_cpnext = commit_transaction; 1024 commit_transaction->t_cpprev = commit_transaction; 1025 } else { 1026 commit_transaction->t_cpnext = 1027 journal->j_checkpoint_transactions; 1028 commit_transaction->t_cpprev = 1029 commit_transaction->t_cpnext->t_cpprev; 1030 commit_transaction->t_cpnext->t_cpprev = 1031 commit_transaction; 1032 commit_transaction->t_cpprev->t_cpnext = 1033 commit_transaction; 1034 } 1035 } 1036 spin_unlock(&journal->j_list_lock); 1037 1038 if (journal->j_commit_callback) 1039 journal->j_commit_callback(journal, commit_transaction); 1040 1041 trace_jbd2_end_commit(journal, commit_transaction); 1042 jbd_debug(1, "JBD2: commit %d complete, head %d\n", 1043 journal->j_commit_sequence, journal->j_tail_sequence); 1044 if (to_free) 1045 kfree(commit_transaction); 1046 1047 wake_up(&journal->j_wait_done_commit); 1048 } 1049