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/marker.h> 20 #include <linux/errno.h> 21 #include <linux/slab.h> 22 #include <linux/mm.h> 23 #include <linux/pagemap.h> 24 #include <linux/jiffies.h> 25 #include <linux/crc32.h> 26 #include <linux/writeback.h> 27 #include <linux/backing-dev.h> 28 #include <linux/bio.h> 29 30 /* 31 * Default IO end handler for temporary BJ_IO buffer_heads. 32 */ 33 static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate) 34 { 35 BUFFER_TRACE(bh, ""); 36 if (uptodate) 37 set_buffer_uptodate(bh); 38 else 39 clear_buffer_uptodate(bh); 40 unlock_buffer(bh); 41 } 42 43 /* 44 * When an ext4 file is truncated, it is possible that some pages are not 45 * successfully freed, because they are attached to a committing transaction. 46 * After the transaction commits, these pages are left on the LRU, with no 47 * ->mapping, and with attached buffers. These pages are trivially reclaimable 48 * by the VM, but their apparent absence upsets the VM accounting, and it makes 49 * the numbers in /proc/meminfo look odd. 50 * 51 * So here, we have a buffer which has just come off the forget list. Look to 52 * see if we can strip all buffers from the backing page. 53 * 54 * Called under lock_journal(), and possibly under journal_datalist_lock. The 55 * caller provided us with a ref against the buffer, and we drop that here. 56 */ 57 static void release_buffer_page(struct buffer_head *bh) 58 { 59 struct page *page; 60 61 if (buffer_dirty(bh)) 62 goto nope; 63 if (atomic_read(&bh->b_count) != 1) 64 goto nope; 65 page = bh->b_page; 66 if (!page) 67 goto nope; 68 if (page->mapping) 69 goto nope; 70 71 /* OK, it's a truncated page */ 72 if (!trylock_page(page)) 73 goto nope; 74 75 page_cache_get(page); 76 __brelse(bh); 77 try_to_free_buffers(page); 78 unlock_page(page); 79 page_cache_release(page); 80 return; 81 82 nope: 83 __brelse(bh); 84 } 85 86 /* 87 * Done it all: now submit the commit record. We should have 88 * cleaned up our previous buffers by now, so if we are in abort 89 * mode we can now just skip the rest of the journal write 90 * entirely. 91 * 92 * Returns 1 if the journal needs to be aborted or 0 on success 93 */ 94 static int journal_submit_commit_record(journal_t *journal, 95 transaction_t *commit_transaction, 96 struct buffer_head **cbh, 97 __u32 crc32_sum) 98 { 99 struct journal_head *descriptor; 100 struct commit_header *tmp; 101 struct buffer_head *bh; 102 int ret; 103 int barrier_done = 0; 104 struct timespec now = current_kernel_time(); 105 106 if (is_journal_aborted(journal)) 107 return 0; 108 109 descriptor = jbd2_journal_get_descriptor_buffer(journal); 110 if (!descriptor) 111 return 1; 112 113 bh = jh2bh(descriptor); 114 115 tmp = (struct commit_header *)bh->b_data; 116 tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); 117 tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK); 118 tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid); 119 tmp->h_commit_sec = cpu_to_be64(now.tv_sec); 120 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec); 121 122 if (JBD2_HAS_COMPAT_FEATURE(journal, 123 JBD2_FEATURE_COMPAT_CHECKSUM)) { 124 tmp->h_chksum_type = JBD2_CRC32_CHKSUM; 125 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE; 126 tmp->h_chksum[0] = cpu_to_be32(crc32_sum); 127 } 128 129 JBUFFER_TRACE(descriptor, "submit commit block"); 130 lock_buffer(bh); 131 clear_buffer_dirty(bh); 132 set_buffer_uptodate(bh); 133 bh->b_end_io = journal_end_buffer_io_sync; 134 135 if (journal->j_flags & JBD2_BARRIER && 136 !JBD2_HAS_INCOMPAT_FEATURE(journal, 137 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 138 set_buffer_ordered(bh); 139 barrier_done = 1; 140 } 141 ret = submit_bh(WRITE_SYNC, bh); 142 if (barrier_done) 143 clear_buffer_ordered(bh); 144 145 /* is it possible for another commit to fail at roughly 146 * the same time as this one? If so, we don't want to 147 * trust the barrier flag in the super, but instead want 148 * to remember if we sent a barrier request 149 */ 150 if (ret == -EOPNOTSUPP && barrier_done) { 151 printk(KERN_WARNING 152 "JBD: barrier-based sync failed on %s - " 153 "disabling barriers\n", journal->j_devname); 154 spin_lock(&journal->j_state_lock); 155 journal->j_flags &= ~JBD2_BARRIER; 156 spin_unlock(&journal->j_state_lock); 157 158 /* And try again, without the barrier */ 159 lock_buffer(bh); 160 set_buffer_uptodate(bh); 161 clear_buffer_dirty(bh); 162 ret = submit_bh(WRITE_SYNC, bh); 163 } 164 *cbh = bh; 165 return ret; 166 } 167 168 /* 169 * This function along with journal_submit_commit_record 170 * allows to write the commit record asynchronously. 171 */ 172 static int journal_wait_on_commit_record(journal_t *journal, 173 struct buffer_head *bh) 174 { 175 int ret = 0; 176 177 retry: 178 clear_buffer_dirty(bh); 179 wait_on_buffer(bh); 180 if (buffer_eopnotsupp(bh) && (journal->j_flags & JBD2_BARRIER)) { 181 printk(KERN_WARNING 182 "JBD2: wait_on_commit_record: sync failed on %s - " 183 "disabling barriers\n", journal->j_devname); 184 spin_lock(&journal->j_state_lock); 185 journal->j_flags &= ~JBD2_BARRIER; 186 spin_unlock(&journal->j_state_lock); 187 188 lock_buffer(bh); 189 clear_buffer_dirty(bh); 190 set_buffer_uptodate(bh); 191 bh->b_end_io = journal_end_buffer_io_sync; 192 193 ret = submit_bh(WRITE_SYNC, bh); 194 if (ret) { 195 unlock_buffer(bh); 196 return ret; 197 } 198 goto retry; 199 } 200 201 if (unlikely(!buffer_uptodate(bh))) 202 ret = -EIO; 203 put_bh(bh); /* One for getblk() */ 204 jbd2_journal_put_journal_head(bh2jh(bh)); 205 206 return ret; 207 } 208 209 /* 210 * write the filemap data using writepage() address_space_operations. 211 * We don't do block allocation here even for delalloc. We don't 212 * use writepages() because with dealyed allocation we may be doing 213 * block allocation in writepages(). 214 */ 215 static int journal_submit_inode_data_buffers(struct address_space *mapping) 216 { 217 int ret; 218 struct writeback_control wbc = { 219 .sync_mode = WB_SYNC_ALL, 220 .nr_to_write = mapping->nrpages * 2, 221 .range_start = 0, 222 .range_end = i_size_read(mapping->host), 223 .for_writepages = 1, 224 }; 225 226 ret = generic_writepages(mapping, &wbc); 227 return ret; 228 } 229 230 /* 231 * Submit all the data buffers of inode associated with the transaction to 232 * disk. 233 * 234 * We are in a committing transaction. Therefore no new inode can be added to 235 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently 236 * operate on from being released while we write out pages. 237 */ 238 static int journal_submit_data_buffers(journal_t *journal, 239 transaction_t *commit_transaction) 240 { 241 struct jbd2_inode *jinode; 242 int err, ret = 0; 243 struct address_space *mapping; 244 245 spin_lock(&journal->j_list_lock); 246 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 247 mapping = jinode->i_vfs_inode->i_mapping; 248 jinode->i_flags |= JI_COMMIT_RUNNING; 249 spin_unlock(&journal->j_list_lock); 250 /* 251 * submit the inode data buffers. We use writepage 252 * instead of writepages. Because writepages can do 253 * block allocation with delalloc. We need to write 254 * only allocated blocks here. 255 */ 256 err = journal_submit_inode_data_buffers(mapping); 257 if (!ret) 258 ret = err; 259 spin_lock(&journal->j_list_lock); 260 J_ASSERT(jinode->i_transaction == commit_transaction); 261 jinode->i_flags &= ~JI_COMMIT_RUNNING; 262 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 263 } 264 spin_unlock(&journal->j_list_lock); 265 return ret; 266 } 267 268 /* 269 * Wait for data submitted for writeout, refile inodes to proper 270 * transaction if needed. 271 * 272 */ 273 static int journal_finish_inode_data_buffers(journal_t *journal, 274 transaction_t *commit_transaction) 275 { 276 struct jbd2_inode *jinode, *next_i; 277 int err, ret = 0; 278 279 /* For locking, see the comment in journal_submit_data_buffers() */ 280 spin_lock(&journal->j_list_lock); 281 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 282 jinode->i_flags |= JI_COMMIT_RUNNING; 283 spin_unlock(&journal->j_list_lock); 284 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping); 285 if (err) { 286 /* 287 * Because AS_EIO is cleared by 288 * wait_on_page_writeback_range(), set it again so 289 * that user process can get -EIO from fsync(). 290 */ 291 set_bit(AS_EIO, 292 &jinode->i_vfs_inode->i_mapping->flags); 293 294 if (!ret) 295 ret = err; 296 } 297 spin_lock(&journal->j_list_lock); 298 jinode->i_flags &= ~JI_COMMIT_RUNNING; 299 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 300 } 301 302 /* Now refile inode to proper lists */ 303 list_for_each_entry_safe(jinode, next_i, 304 &commit_transaction->t_inode_list, i_list) { 305 list_del(&jinode->i_list); 306 if (jinode->i_next_transaction) { 307 jinode->i_transaction = jinode->i_next_transaction; 308 jinode->i_next_transaction = NULL; 309 list_add(&jinode->i_list, 310 &jinode->i_transaction->t_inode_list); 311 } else { 312 jinode->i_transaction = NULL; 313 } 314 } 315 spin_unlock(&journal->j_list_lock); 316 317 return ret; 318 } 319 320 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh) 321 { 322 struct page *page = bh->b_page; 323 char *addr; 324 __u32 checksum; 325 326 addr = kmap_atomic(page, KM_USER0); 327 checksum = crc32_be(crc32_sum, 328 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size); 329 kunmap_atomic(addr, KM_USER0); 330 331 return checksum; 332 } 333 334 static void write_tag_block(int tag_bytes, journal_block_tag_t *tag, 335 unsigned long long block) 336 { 337 tag->t_blocknr = cpu_to_be32(block & (u32)~0); 338 if (tag_bytes > JBD2_TAG_SIZE32) 339 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1); 340 } 341 342 /* 343 * jbd2_journal_commit_transaction 344 * 345 * The primary function for committing a transaction to the log. This 346 * function is called by the journal thread to begin a complete commit. 347 */ 348 void jbd2_journal_commit_transaction(journal_t *journal) 349 { 350 struct transaction_stats_s stats; 351 transaction_t *commit_transaction; 352 struct journal_head *jh, *new_jh, *descriptor; 353 struct buffer_head **wbuf = journal->j_wbuf; 354 int bufs; 355 int flags; 356 int err; 357 unsigned long long blocknr; 358 ktime_t start_time; 359 u64 commit_time; 360 char *tagp = NULL; 361 journal_header_t *header; 362 journal_block_tag_t *tag = NULL; 363 int space_left = 0; 364 int first_tag = 0; 365 int tag_flag; 366 int i, to_free = 0; 367 int tag_bytes = journal_tag_bytes(journal); 368 struct buffer_head *cbh = NULL; /* For transactional checksums */ 369 __u32 crc32_sum = ~0; 370 371 /* 372 * First job: lock down the current transaction and wait for 373 * all outstanding updates to complete. 374 */ 375 376 #ifdef COMMIT_STATS 377 spin_lock(&journal->j_list_lock); 378 summarise_journal_usage(journal); 379 spin_unlock(&journal->j_list_lock); 380 #endif 381 382 /* Do we need to erase the effects of a prior jbd2_journal_flush? */ 383 if (journal->j_flags & JBD2_FLUSHED) { 384 jbd_debug(3, "super block updated\n"); 385 jbd2_journal_update_superblock(journal, 1); 386 } else { 387 jbd_debug(3, "superblock not updated\n"); 388 } 389 390 J_ASSERT(journal->j_running_transaction != NULL); 391 J_ASSERT(journal->j_committing_transaction == NULL); 392 393 commit_transaction = journal->j_running_transaction; 394 J_ASSERT(commit_transaction->t_state == T_RUNNING); 395 396 trace_mark(jbd2_start_commit, "dev %s transaction %d", 397 journal->j_devname, commit_transaction->t_tid); 398 jbd_debug(1, "JBD: starting commit of transaction %d\n", 399 commit_transaction->t_tid); 400 401 spin_lock(&journal->j_state_lock); 402 commit_transaction->t_state = T_LOCKED; 403 404 stats.u.run.rs_wait = commit_transaction->t_max_wait; 405 stats.u.run.rs_locked = jiffies; 406 stats.u.run.rs_running = jbd2_time_diff(commit_transaction->t_start, 407 stats.u.run.rs_locked); 408 409 spin_lock(&commit_transaction->t_handle_lock); 410 while (commit_transaction->t_updates) { 411 DEFINE_WAIT(wait); 412 413 prepare_to_wait(&journal->j_wait_updates, &wait, 414 TASK_UNINTERRUPTIBLE); 415 if (commit_transaction->t_updates) { 416 spin_unlock(&commit_transaction->t_handle_lock); 417 spin_unlock(&journal->j_state_lock); 418 schedule(); 419 spin_lock(&journal->j_state_lock); 420 spin_lock(&commit_transaction->t_handle_lock); 421 } 422 finish_wait(&journal->j_wait_updates, &wait); 423 } 424 spin_unlock(&commit_transaction->t_handle_lock); 425 426 J_ASSERT (commit_transaction->t_outstanding_credits <= 427 journal->j_max_transaction_buffers); 428 429 /* 430 * First thing we are allowed to do is to discard any remaining 431 * BJ_Reserved buffers. Note, it is _not_ permissible to assume 432 * that there are no such buffers: if a large filesystem 433 * operation like a truncate needs to split itself over multiple 434 * transactions, then it may try to do a jbd2_journal_restart() while 435 * there are still BJ_Reserved buffers outstanding. These must 436 * be released cleanly from the current transaction. 437 * 438 * In this case, the filesystem must still reserve write access 439 * again before modifying the buffer in the new transaction, but 440 * we do not require it to remember exactly which old buffers it 441 * has reserved. This is consistent with the existing behaviour 442 * that multiple jbd2_journal_get_write_access() calls to the same 443 * buffer are perfectly permissable. 444 */ 445 while (commit_transaction->t_reserved_list) { 446 jh = commit_transaction->t_reserved_list; 447 JBUFFER_TRACE(jh, "reserved, unused: refile"); 448 /* 449 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may 450 * leave undo-committed data. 451 */ 452 if (jh->b_committed_data) { 453 struct buffer_head *bh = jh2bh(jh); 454 455 jbd_lock_bh_state(bh); 456 jbd2_free(jh->b_committed_data, bh->b_size); 457 jh->b_committed_data = NULL; 458 jbd_unlock_bh_state(bh); 459 } 460 jbd2_journal_refile_buffer(journal, jh); 461 } 462 463 /* 464 * Now try to drop any written-back buffers from the journal's 465 * checkpoint lists. We do this *before* commit because it potentially 466 * frees some memory 467 */ 468 spin_lock(&journal->j_list_lock); 469 __jbd2_journal_clean_checkpoint_list(journal); 470 spin_unlock(&journal->j_list_lock); 471 472 jbd_debug (3, "JBD: commit phase 1\n"); 473 474 /* 475 * Switch to a new revoke table. 476 */ 477 jbd2_journal_switch_revoke_table(journal); 478 479 stats.u.run.rs_flushing = jiffies; 480 stats.u.run.rs_locked = jbd2_time_diff(stats.u.run.rs_locked, 481 stats.u.run.rs_flushing); 482 483 commit_transaction->t_state = T_FLUSH; 484 journal->j_committing_transaction = commit_transaction; 485 journal->j_running_transaction = NULL; 486 start_time = ktime_get(); 487 commit_transaction->t_log_start = journal->j_head; 488 wake_up(&journal->j_wait_transaction_locked); 489 spin_unlock(&journal->j_state_lock); 490 491 jbd_debug (3, "JBD: commit phase 2\n"); 492 493 /* 494 * Now start flushing things to disk, in the order they appear 495 * on the transaction lists. Data blocks go first. 496 */ 497 err = journal_submit_data_buffers(journal, commit_transaction); 498 if (err) 499 jbd2_journal_abort(journal, err); 500 501 jbd2_journal_write_revoke_records(journal, commit_transaction); 502 503 jbd_debug(3, "JBD: commit phase 2\n"); 504 505 /* 506 * Way to go: we have now written out all of the data for a 507 * transaction! Now comes the tricky part: we need to write out 508 * metadata. Loop over the transaction's entire buffer list: 509 */ 510 spin_lock(&journal->j_state_lock); 511 commit_transaction->t_state = T_COMMIT; 512 spin_unlock(&journal->j_state_lock); 513 514 stats.u.run.rs_logging = jiffies; 515 stats.u.run.rs_flushing = jbd2_time_diff(stats.u.run.rs_flushing, 516 stats.u.run.rs_logging); 517 stats.u.run.rs_blocks = commit_transaction->t_outstanding_credits; 518 stats.u.run.rs_blocks_logged = 0; 519 520 J_ASSERT(commit_transaction->t_nr_buffers <= 521 commit_transaction->t_outstanding_credits); 522 523 err = 0; 524 descriptor = NULL; 525 bufs = 0; 526 while (commit_transaction->t_buffers) { 527 528 /* Find the next buffer to be journaled... */ 529 530 jh = commit_transaction->t_buffers; 531 532 /* If we're in abort mode, we just un-journal the buffer and 533 release it. */ 534 535 if (is_journal_aborted(journal)) { 536 clear_buffer_jbddirty(jh2bh(jh)); 537 JBUFFER_TRACE(jh, "journal is aborting: refile"); 538 jbd2_buffer_abort_trigger(jh, 539 jh->b_frozen_data ? 540 jh->b_frozen_triggers : 541 jh->b_triggers); 542 jbd2_journal_refile_buffer(journal, jh); 543 /* If that was the last one, we need to clean up 544 * any descriptor buffers which may have been 545 * already allocated, even if we are now 546 * aborting. */ 547 if (!commit_transaction->t_buffers) 548 goto start_journal_io; 549 continue; 550 } 551 552 /* Make sure we have a descriptor block in which to 553 record the metadata buffer. */ 554 555 if (!descriptor) { 556 struct buffer_head *bh; 557 558 J_ASSERT (bufs == 0); 559 560 jbd_debug(4, "JBD: get descriptor\n"); 561 562 descriptor = jbd2_journal_get_descriptor_buffer(journal); 563 if (!descriptor) { 564 jbd2_journal_abort(journal, -EIO); 565 continue; 566 } 567 568 bh = jh2bh(descriptor); 569 jbd_debug(4, "JBD: got buffer %llu (%p)\n", 570 (unsigned long long)bh->b_blocknr, bh->b_data); 571 header = (journal_header_t *)&bh->b_data[0]; 572 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); 573 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK); 574 header->h_sequence = cpu_to_be32(commit_transaction->t_tid); 575 576 tagp = &bh->b_data[sizeof(journal_header_t)]; 577 space_left = bh->b_size - sizeof(journal_header_t); 578 first_tag = 1; 579 set_buffer_jwrite(bh); 580 set_buffer_dirty(bh); 581 wbuf[bufs++] = bh; 582 583 /* Record it so that we can wait for IO 584 completion later */ 585 BUFFER_TRACE(bh, "ph3: file as descriptor"); 586 jbd2_journal_file_buffer(descriptor, commit_transaction, 587 BJ_LogCtl); 588 } 589 590 /* Where is the buffer to be written? */ 591 592 err = jbd2_journal_next_log_block(journal, &blocknr); 593 /* If the block mapping failed, just abandon the buffer 594 and repeat this loop: we'll fall into the 595 refile-on-abort condition above. */ 596 if (err) { 597 jbd2_journal_abort(journal, err); 598 continue; 599 } 600 601 /* 602 * start_this_handle() uses t_outstanding_credits to determine 603 * the free space in the log, but this counter is changed 604 * by jbd2_journal_next_log_block() also. 605 */ 606 commit_transaction->t_outstanding_credits--; 607 608 /* Bump b_count to prevent truncate from stumbling over 609 the shadowed buffer! @@@ This can go if we ever get 610 rid of the BJ_IO/BJ_Shadow pairing of buffers. */ 611 atomic_inc(&jh2bh(jh)->b_count); 612 613 /* Make a temporary IO buffer with which to write it out 614 (this will requeue both the metadata buffer and the 615 temporary IO buffer). new_bh goes on BJ_IO*/ 616 617 set_bit(BH_JWrite, &jh2bh(jh)->b_state); 618 /* 619 * akpm: jbd2_journal_write_metadata_buffer() sets 620 * new_bh->b_transaction to commit_transaction. 621 * We need to clean this up before we release new_bh 622 * (which is of type BJ_IO) 623 */ 624 JBUFFER_TRACE(jh, "ph3: write metadata"); 625 flags = jbd2_journal_write_metadata_buffer(commit_transaction, 626 jh, &new_jh, blocknr); 627 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state); 628 wbuf[bufs++] = jh2bh(new_jh); 629 630 /* Record the new block's tag in the current descriptor 631 buffer */ 632 633 tag_flag = 0; 634 if (flags & 1) 635 tag_flag |= JBD2_FLAG_ESCAPE; 636 if (!first_tag) 637 tag_flag |= JBD2_FLAG_SAME_UUID; 638 639 tag = (journal_block_tag_t *) tagp; 640 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr); 641 tag->t_flags = cpu_to_be32(tag_flag); 642 tagp += tag_bytes; 643 space_left -= tag_bytes; 644 645 if (first_tag) { 646 memcpy (tagp, journal->j_uuid, 16); 647 tagp += 16; 648 space_left -= 16; 649 first_tag = 0; 650 } 651 652 /* If there's no more to do, or if the descriptor is full, 653 let the IO rip! */ 654 655 if (bufs == journal->j_wbufsize || 656 commit_transaction->t_buffers == NULL || 657 space_left < tag_bytes + 16) { 658 659 jbd_debug(4, "JBD: Submit %d IOs\n", bufs); 660 661 /* Write an end-of-descriptor marker before 662 submitting the IOs. "tag" still points to 663 the last tag we set up. */ 664 665 tag->t_flags |= cpu_to_be32(JBD2_FLAG_LAST_TAG); 666 667 start_journal_io: 668 for (i = 0; i < bufs; i++) { 669 struct buffer_head *bh = wbuf[i]; 670 /* 671 * Compute checksum. 672 */ 673 if (JBD2_HAS_COMPAT_FEATURE(journal, 674 JBD2_FEATURE_COMPAT_CHECKSUM)) { 675 crc32_sum = 676 jbd2_checksum_data(crc32_sum, bh); 677 } 678 679 lock_buffer(bh); 680 clear_buffer_dirty(bh); 681 set_buffer_uptodate(bh); 682 bh->b_end_io = journal_end_buffer_io_sync; 683 submit_bh(WRITE, bh); 684 } 685 cond_resched(); 686 stats.u.run.rs_blocks_logged += bufs; 687 688 /* Force a new descriptor to be generated next 689 time round the loop. */ 690 descriptor = NULL; 691 bufs = 0; 692 } 693 } 694 695 /* Done it all: now write the commit record asynchronously. */ 696 697 if (JBD2_HAS_INCOMPAT_FEATURE(journal, 698 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 699 err = journal_submit_commit_record(journal, commit_transaction, 700 &cbh, crc32_sum); 701 if (err) 702 __jbd2_journal_abort_hard(journal); 703 } 704 705 /* 706 * This is the right place to wait for data buffers both for ASYNC 707 * and !ASYNC commit. If commit is ASYNC, we need to wait only after 708 * the commit block went to disk (which happens above). If commit is 709 * SYNC, we need to wait for data buffers before we start writing 710 * commit block, which happens below in such setting. 711 */ 712 err = journal_finish_inode_data_buffers(journal, commit_transaction); 713 if (err) { 714 printk(KERN_WARNING 715 "JBD2: Detected IO errors while flushing file data " 716 "on %s\n", journal->j_devname); 717 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR) 718 jbd2_journal_abort(journal, err); 719 err = 0; 720 } 721 722 /* Lo and behold: we have just managed to send a transaction to 723 the log. Before we can commit it, wait for the IO so far to 724 complete. Control buffers being written are on the 725 transaction's t_log_list queue, and metadata buffers are on 726 the t_iobuf_list queue. 727 728 Wait for the buffers in reverse order. That way we are 729 less likely to be woken up until all IOs have completed, and 730 so we incur less scheduling load. 731 */ 732 733 jbd_debug(3, "JBD: commit phase 3\n"); 734 735 /* 736 * akpm: these are BJ_IO, and j_list_lock is not needed. 737 * See __journal_try_to_free_buffer. 738 */ 739 wait_for_iobuf: 740 while (commit_transaction->t_iobuf_list != NULL) { 741 struct buffer_head *bh; 742 743 jh = commit_transaction->t_iobuf_list->b_tprev; 744 bh = jh2bh(jh); 745 if (buffer_locked(bh)) { 746 wait_on_buffer(bh); 747 goto wait_for_iobuf; 748 } 749 if (cond_resched()) 750 goto wait_for_iobuf; 751 752 if (unlikely(!buffer_uptodate(bh))) 753 err = -EIO; 754 755 clear_buffer_jwrite(bh); 756 757 JBUFFER_TRACE(jh, "ph4: unfile after journal write"); 758 jbd2_journal_unfile_buffer(journal, jh); 759 760 /* 761 * ->t_iobuf_list should contain only dummy buffer_heads 762 * which were created by jbd2_journal_write_metadata_buffer(). 763 */ 764 BUFFER_TRACE(bh, "dumping temporary bh"); 765 jbd2_journal_put_journal_head(jh); 766 __brelse(bh); 767 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); 768 free_buffer_head(bh); 769 770 /* We also have to unlock and free the corresponding 771 shadowed buffer */ 772 jh = commit_transaction->t_shadow_list->b_tprev; 773 bh = jh2bh(jh); 774 clear_bit(BH_JWrite, &bh->b_state); 775 J_ASSERT_BH(bh, buffer_jbddirty(bh)); 776 777 /* The metadata is now released for reuse, but we need 778 to remember it against this transaction so that when 779 we finally commit, we can do any checkpointing 780 required. */ 781 JBUFFER_TRACE(jh, "file as BJ_Forget"); 782 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget); 783 /* Wake up any transactions which were waiting for this 784 IO to complete */ 785 wake_up_bit(&bh->b_state, BH_Unshadow); 786 JBUFFER_TRACE(jh, "brelse shadowed buffer"); 787 __brelse(bh); 788 } 789 790 J_ASSERT (commit_transaction->t_shadow_list == NULL); 791 792 jbd_debug(3, "JBD: commit phase 4\n"); 793 794 /* Here we wait for the revoke record and descriptor record buffers */ 795 wait_for_ctlbuf: 796 while (commit_transaction->t_log_list != NULL) { 797 struct buffer_head *bh; 798 799 jh = commit_transaction->t_log_list->b_tprev; 800 bh = jh2bh(jh); 801 if (buffer_locked(bh)) { 802 wait_on_buffer(bh); 803 goto wait_for_ctlbuf; 804 } 805 if (cond_resched()) 806 goto wait_for_ctlbuf; 807 808 if (unlikely(!buffer_uptodate(bh))) 809 err = -EIO; 810 811 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); 812 clear_buffer_jwrite(bh); 813 jbd2_journal_unfile_buffer(journal, jh); 814 jbd2_journal_put_journal_head(jh); 815 __brelse(bh); /* One for getblk */ 816 /* AKPM: bforget here */ 817 } 818 819 if (err) 820 jbd2_journal_abort(journal, err); 821 822 jbd_debug(3, "JBD: commit phase 5\n"); 823 824 if (!JBD2_HAS_INCOMPAT_FEATURE(journal, 825 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 826 err = journal_submit_commit_record(journal, commit_transaction, 827 &cbh, crc32_sum); 828 if (err) 829 __jbd2_journal_abort_hard(journal); 830 } 831 if (!err && !is_journal_aborted(journal)) 832 err = journal_wait_on_commit_record(journal, cbh); 833 834 if (err) 835 jbd2_journal_abort(journal, err); 836 837 /* End of a transaction! Finally, we can do checkpoint 838 processing: any buffers committed as a result of this 839 transaction can be removed from any checkpoint list it was on 840 before. */ 841 842 jbd_debug(3, "JBD: commit phase 6\n"); 843 844 J_ASSERT(list_empty(&commit_transaction->t_inode_list)); 845 J_ASSERT(commit_transaction->t_buffers == NULL); 846 J_ASSERT(commit_transaction->t_checkpoint_list == NULL); 847 J_ASSERT(commit_transaction->t_iobuf_list == NULL); 848 J_ASSERT(commit_transaction->t_shadow_list == NULL); 849 J_ASSERT(commit_transaction->t_log_list == NULL); 850 851 restart_loop: 852 /* 853 * As there are other places (journal_unmap_buffer()) adding buffers 854 * to this list we have to be careful and hold the j_list_lock. 855 */ 856 spin_lock(&journal->j_list_lock); 857 while (commit_transaction->t_forget) { 858 transaction_t *cp_transaction; 859 struct buffer_head *bh; 860 861 jh = commit_transaction->t_forget; 862 spin_unlock(&journal->j_list_lock); 863 bh = jh2bh(jh); 864 jbd_lock_bh_state(bh); 865 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction || 866 jh->b_transaction == journal->j_running_transaction); 867 868 /* 869 * If there is undo-protected committed data against 870 * this buffer, then we can remove it now. If it is a 871 * buffer needing such protection, the old frozen_data 872 * field now points to a committed version of the 873 * buffer, so rotate that field to the new committed 874 * data. 875 * 876 * Otherwise, we can just throw away the frozen data now. 877 * 878 * We also know that the frozen data has already fired 879 * its triggers if they exist, so we can clear that too. 880 */ 881 if (jh->b_committed_data) { 882 jbd2_free(jh->b_committed_data, bh->b_size); 883 jh->b_committed_data = NULL; 884 if (jh->b_frozen_data) { 885 jh->b_committed_data = jh->b_frozen_data; 886 jh->b_frozen_data = NULL; 887 jh->b_frozen_triggers = NULL; 888 } 889 } else if (jh->b_frozen_data) { 890 jbd2_free(jh->b_frozen_data, bh->b_size); 891 jh->b_frozen_data = NULL; 892 jh->b_frozen_triggers = NULL; 893 } 894 895 spin_lock(&journal->j_list_lock); 896 cp_transaction = jh->b_cp_transaction; 897 if (cp_transaction) { 898 JBUFFER_TRACE(jh, "remove from old cp transaction"); 899 cp_transaction->t_chp_stats.cs_dropped++; 900 __jbd2_journal_remove_checkpoint(jh); 901 } 902 903 /* Only re-checkpoint the buffer_head if it is marked 904 * dirty. If the buffer was added to the BJ_Forget list 905 * by jbd2_journal_forget, it may no longer be dirty and 906 * there's no point in keeping a checkpoint record for 907 * it. */ 908 909 /* A buffer which has been freed while still being 910 * journaled by a previous transaction may end up still 911 * being dirty here, but we want to avoid writing back 912 * that buffer in the future now that the last use has 913 * been committed. That's not only a performance gain, 914 * it also stops aliasing problems if the buffer is left 915 * behind for writeback and gets reallocated for another 916 * use in a different page. */ 917 if (buffer_freed(bh)) { 918 clear_buffer_freed(bh); 919 clear_buffer_jbddirty(bh); 920 } 921 922 if (buffer_jbddirty(bh)) { 923 JBUFFER_TRACE(jh, "add to new checkpointing trans"); 924 __jbd2_journal_insert_checkpoint(jh, commit_transaction); 925 if (is_journal_aborted(journal)) 926 clear_buffer_jbddirty(bh); 927 JBUFFER_TRACE(jh, "refile for checkpoint writeback"); 928 __jbd2_journal_refile_buffer(jh); 929 jbd_unlock_bh_state(bh); 930 } else { 931 J_ASSERT_BH(bh, !buffer_dirty(bh)); 932 /* The buffer on BJ_Forget list and not jbddirty means 933 * it has been freed by this transaction and hence it 934 * could not have been reallocated until this 935 * transaction has committed. *BUT* it could be 936 * reallocated once we have written all the data to 937 * disk and before we process the buffer on BJ_Forget 938 * list. */ 939 JBUFFER_TRACE(jh, "refile or unfile freed buffer"); 940 __jbd2_journal_refile_buffer(jh); 941 if (!jh->b_transaction) { 942 jbd_unlock_bh_state(bh); 943 /* needs a brelse */ 944 jbd2_journal_remove_journal_head(bh); 945 release_buffer_page(bh); 946 } else 947 jbd_unlock_bh_state(bh); 948 } 949 cond_resched_lock(&journal->j_list_lock); 950 } 951 spin_unlock(&journal->j_list_lock); 952 /* 953 * This is a bit sleazy. We use j_list_lock to protect transition 954 * of a transaction into T_FINISHED state and calling 955 * __jbd2_journal_drop_transaction(). Otherwise we could race with 956 * other checkpointing code processing the transaction... 957 */ 958 spin_lock(&journal->j_state_lock); 959 spin_lock(&journal->j_list_lock); 960 /* 961 * Now recheck if some buffers did not get attached to the transaction 962 * while the lock was dropped... 963 */ 964 if (commit_transaction->t_forget) { 965 spin_unlock(&journal->j_list_lock); 966 spin_unlock(&journal->j_state_lock); 967 goto restart_loop; 968 } 969 970 /* Done with this transaction! */ 971 972 jbd_debug(3, "JBD: commit phase 7\n"); 973 974 J_ASSERT(commit_transaction->t_state == T_COMMIT); 975 976 commit_transaction->t_start = jiffies; 977 stats.u.run.rs_logging = jbd2_time_diff(stats.u.run.rs_logging, 978 commit_transaction->t_start); 979 980 /* 981 * File the transaction for history 982 */ 983 stats.ts_type = JBD2_STATS_RUN; 984 stats.ts_tid = commit_transaction->t_tid; 985 stats.u.run.rs_handle_count = commit_transaction->t_handle_count; 986 spin_lock(&journal->j_history_lock); 987 memcpy(journal->j_history + journal->j_history_cur, &stats, 988 sizeof(stats)); 989 if (++journal->j_history_cur == journal->j_history_max) 990 journal->j_history_cur = 0; 991 992 /* 993 * Calculate overall stats 994 */ 995 journal->j_stats.ts_tid++; 996 journal->j_stats.u.run.rs_wait += stats.u.run.rs_wait; 997 journal->j_stats.u.run.rs_running += stats.u.run.rs_running; 998 journal->j_stats.u.run.rs_locked += stats.u.run.rs_locked; 999 journal->j_stats.u.run.rs_flushing += stats.u.run.rs_flushing; 1000 journal->j_stats.u.run.rs_logging += stats.u.run.rs_logging; 1001 journal->j_stats.u.run.rs_handle_count += stats.u.run.rs_handle_count; 1002 journal->j_stats.u.run.rs_blocks += stats.u.run.rs_blocks; 1003 journal->j_stats.u.run.rs_blocks_logged += stats.u.run.rs_blocks_logged; 1004 spin_unlock(&journal->j_history_lock); 1005 1006 commit_transaction->t_state = T_FINISHED; 1007 J_ASSERT(commit_transaction == journal->j_committing_transaction); 1008 journal->j_commit_sequence = commit_transaction->t_tid; 1009 journal->j_committing_transaction = NULL; 1010 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); 1011 1012 /* 1013 * weight the commit time higher than the average time so we don't 1014 * react too strongly to vast changes in the commit time 1015 */ 1016 if (likely(journal->j_average_commit_time)) 1017 journal->j_average_commit_time = (commit_time + 1018 journal->j_average_commit_time*3) / 4; 1019 else 1020 journal->j_average_commit_time = commit_time; 1021 spin_unlock(&journal->j_state_lock); 1022 1023 if (commit_transaction->t_checkpoint_list == NULL && 1024 commit_transaction->t_checkpoint_io_list == NULL) { 1025 __jbd2_journal_drop_transaction(journal, commit_transaction); 1026 to_free = 1; 1027 } else { 1028 if (journal->j_checkpoint_transactions == NULL) { 1029 journal->j_checkpoint_transactions = commit_transaction; 1030 commit_transaction->t_cpnext = commit_transaction; 1031 commit_transaction->t_cpprev = commit_transaction; 1032 } else { 1033 commit_transaction->t_cpnext = 1034 journal->j_checkpoint_transactions; 1035 commit_transaction->t_cpprev = 1036 commit_transaction->t_cpnext->t_cpprev; 1037 commit_transaction->t_cpnext->t_cpprev = 1038 commit_transaction; 1039 commit_transaction->t_cpprev->t_cpnext = 1040 commit_transaction; 1041 } 1042 } 1043 spin_unlock(&journal->j_list_lock); 1044 1045 if (journal->j_commit_callback) 1046 journal->j_commit_callback(journal, commit_transaction); 1047 1048 trace_mark(jbd2_end_commit, "dev %s transaction %d head %d", 1049 journal->j_devname, commit_transaction->t_tid, 1050 journal->j_tail_sequence); 1051 jbd_debug(1, "JBD: commit %d complete, head %d\n", 1052 journal->j_commit_sequence, journal->j_tail_sequence); 1053 if (to_free) 1054 kfree(commit_transaction); 1055 1056 wake_up(&journal->j_wait_done_commit); 1057 } 1058