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 int write_op = WRITE; 371 372 /* 373 * First job: lock down the current transaction and wait for 374 * all outstanding updates to complete. 375 */ 376 377 #ifdef COMMIT_STATS 378 spin_lock(&journal->j_list_lock); 379 summarise_journal_usage(journal); 380 spin_unlock(&journal->j_list_lock); 381 #endif 382 383 /* Do we need to erase the effects of a prior jbd2_journal_flush? */ 384 if (journal->j_flags & JBD2_FLUSHED) { 385 jbd_debug(3, "super block updated\n"); 386 jbd2_journal_update_superblock(journal, 1); 387 } else { 388 jbd_debug(3, "superblock not updated\n"); 389 } 390 391 J_ASSERT(journal->j_running_transaction != NULL); 392 J_ASSERT(journal->j_committing_transaction == NULL); 393 394 commit_transaction = journal->j_running_transaction; 395 J_ASSERT(commit_transaction->t_state == T_RUNNING); 396 397 trace_mark(jbd2_start_commit, "dev %s transaction %d", 398 journal->j_devname, commit_transaction->t_tid); 399 jbd_debug(1, "JBD: starting commit of transaction %d\n", 400 commit_transaction->t_tid); 401 402 spin_lock(&journal->j_state_lock); 403 commit_transaction->t_state = T_LOCKED; 404 405 if (commit_transaction->t_synchronous_commit) 406 write_op = WRITE_SYNC; 407 stats.u.run.rs_wait = commit_transaction->t_max_wait; 408 stats.u.run.rs_locked = jiffies; 409 stats.u.run.rs_running = jbd2_time_diff(commit_transaction->t_start, 410 stats.u.run.rs_locked); 411 412 spin_lock(&commit_transaction->t_handle_lock); 413 while (commit_transaction->t_updates) { 414 DEFINE_WAIT(wait); 415 416 prepare_to_wait(&journal->j_wait_updates, &wait, 417 TASK_UNINTERRUPTIBLE); 418 if (commit_transaction->t_updates) { 419 spin_unlock(&commit_transaction->t_handle_lock); 420 spin_unlock(&journal->j_state_lock); 421 schedule(); 422 spin_lock(&journal->j_state_lock); 423 spin_lock(&commit_transaction->t_handle_lock); 424 } 425 finish_wait(&journal->j_wait_updates, &wait); 426 } 427 spin_unlock(&commit_transaction->t_handle_lock); 428 429 J_ASSERT (commit_transaction->t_outstanding_credits <= 430 journal->j_max_transaction_buffers); 431 432 /* 433 * First thing we are allowed to do is to discard any remaining 434 * BJ_Reserved buffers. Note, it is _not_ permissible to assume 435 * that there are no such buffers: if a large filesystem 436 * operation like a truncate needs to split itself over multiple 437 * transactions, then it may try to do a jbd2_journal_restart() while 438 * there are still BJ_Reserved buffers outstanding. These must 439 * be released cleanly from the current transaction. 440 * 441 * In this case, the filesystem must still reserve write access 442 * again before modifying the buffer in the new transaction, but 443 * we do not require it to remember exactly which old buffers it 444 * has reserved. This is consistent with the existing behaviour 445 * that multiple jbd2_journal_get_write_access() calls to the same 446 * buffer are perfectly permissable. 447 */ 448 while (commit_transaction->t_reserved_list) { 449 jh = commit_transaction->t_reserved_list; 450 JBUFFER_TRACE(jh, "reserved, unused: refile"); 451 /* 452 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may 453 * leave undo-committed data. 454 */ 455 if (jh->b_committed_data) { 456 struct buffer_head *bh = jh2bh(jh); 457 458 jbd_lock_bh_state(bh); 459 jbd2_free(jh->b_committed_data, bh->b_size); 460 jh->b_committed_data = NULL; 461 jbd_unlock_bh_state(bh); 462 } 463 jbd2_journal_refile_buffer(journal, jh); 464 } 465 466 /* 467 * Now try to drop any written-back buffers from the journal's 468 * checkpoint lists. We do this *before* commit because it potentially 469 * frees some memory 470 */ 471 spin_lock(&journal->j_list_lock); 472 __jbd2_journal_clean_checkpoint_list(journal); 473 spin_unlock(&journal->j_list_lock); 474 475 jbd_debug (3, "JBD: commit phase 1\n"); 476 477 /* 478 * Switch to a new revoke table. 479 */ 480 jbd2_journal_switch_revoke_table(journal); 481 482 stats.u.run.rs_flushing = jiffies; 483 stats.u.run.rs_locked = jbd2_time_diff(stats.u.run.rs_locked, 484 stats.u.run.rs_flushing); 485 486 commit_transaction->t_state = T_FLUSH; 487 journal->j_committing_transaction = commit_transaction; 488 journal->j_running_transaction = NULL; 489 start_time = ktime_get(); 490 commit_transaction->t_log_start = journal->j_head; 491 wake_up(&journal->j_wait_transaction_locked); 492 spin_unlock(&journal->j_state_lock); 493 494 jbd_debug (3, "JBD: commit phase 2\n"); 495 496 /* 497 * Now start flushing things to disk, in the order they appear 498 * on the transaction lists. Data blocks go first. 499 */ 500 err = journal_submit_data_buffers(journal, commit_transaction); 501 if (err) 502 jbd2_journal_abort(journal, err); 503 504 jbd2_journal_write_revoke_records(journal, commit_transaction); 505 506 jbd_debug(3, "JBD: commit phase 2\n"); 507 508 /* 509 * Way to go: we have now written out all of the data for a 510 * transaction! Now comes the tricky part: we need to write out 511 * metadata. Loop over the transaction's entire buffer list: 512 */ 513 spin_lock(&journal->j_state_lock); 514 commit_transaction->t_state = T_COMMIT; 515 spin_unlock(&journal->j_state_lock); 516 517 stats.u.run.rs_logging = jiffies; 518 stats.u.run.rs_flushing = jbd2_time_diff(stats.u.run.rs_flushing, 519 stats.u.run.rs_logging); 520 stats.u.run.rs_blocks = commit_transaction->t_outstanding_credits; 521 stats.u.run.rs_blocks_logged = 0; 522 523 J_ASSERT(commit_transaction->t_nr_buffers <= 524 commit_transaction->t_outstanding_credits); 525 526 err = 0; 527 descriptor = NULL; 528 bufs = 0; 529 while (commit_transaction->t_buffers) { 530 531 /* Find the next buffer to be journaled... */ 532 533 jh = commit_transaction->t_buffers; 534 535 /* If we're in abort mode, we just un-journal the buffer and 536 release it. */ 537 538 if (is_journal_aborted(journal)) { 539 clear_buffer_jbddirty(jh2bh(jh)); 540 JBUFFER_TRACE(jh, "journal is aborting: refile"); 541 jbd2_buffer_abort_trigger(jh, 542 jh->b_frozen_data ? 543 jh->b_frozen_triggers : 544 jh->b_triggers); 545 jbd2_journal_refile_buffer(journal, jh); 546 /* If that was the last one, we need to clean up 547 * any descriptor buffers which may have been 548 * already allocated, even if we are now 549 * aborting. */ 550 if (!commit_transaction->t_buffers) 551 goto start_journal_io; 552 continue; 553 } 554 555 /* Make sure we have a descriptor block in which to 556 record the metadata buffer. */ 557 558 if (!descriptor) { 559 struct buffer_head *bh; 560 561 J_ASSERT (bufs == 0); 562 563 jbd_debug(4, "JBD: get descriptor\n"); 564 565 descriptor = jbd2_journal_get_descriptor_buffer(journal); 566 if (!descriptor) { 567 jbd2_journal_abort(journal, -EIO); 568 continue; 569 } 570 571 bh = jh2bh(descriptor); 572 jbd_debug(4, "JBD: got buffer %llu (%p)\n", 573 (unsigned long long)bh->b_blocknr, bh->b_data); 574 header = (journal_header_t *)&bh->b_data[0]; 575 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); 576 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK); 577 header->h_sequence = cpu_to_be32(commit_transaction->t_tid); 578 579 tagp = &bh->b_data[sizeof(journal_header_t)]; 580 space_left = bh->b_size - sizeof(journal_header_t); 581 first_tag = 1; 582 set_buffer_jwrite(bh); 583 set_buffer_dirty(bh); 584 wbuf[bufs++] = bh; 585 586 /* Record it so that we can wait for IO 587 completion later */ 588 BUFFER_TRACE(bh, "ph3: file as descriptor"); 589 jbd2_journal_file_buffer(descriptor, commit_transaction, 590 BJ_LogCtl); 591 } 592 593 /* Where is the buffer to be written? */ 594 595 err = jbd2_journal_next_log_block(journal, &blocknr); 596 /* If the block mapping failed, just abandon the buffer 597 and repeat this loop: we'll fall into the 598 refile-on-abort condition above. */ 599 if (err) { 600 jbd2_journal_abort(journal, err); 601 continue; 602 } 603 604 /* 605 * start_this_handle() uses t_outstanding_credits to determine 606 * the free space in the log, but this counter is changed 607 * by jbd2_journal_next_log_block() also. 608 */ 609 commit_transaction->t_outstanding_credits--; 610 611 /* Bump b_count to prevent truncate from stumbling over 612 the shadowed buffer! @@@ This can go if we ever get 613 rid of the BJ_IO/BJ_Shadow pairing of buffers. */ 614 atomic_inc(&jh2bh(jh)->b_count); 615 616 /* Make a temporary IO buffer with which to write it out 617 (this will requeue both the metadata buffer and the 618 temporary IO buffer). new_bh goes on BJ_IO*/ 619 620 set_bit(BH_JWrite, &jh2bh(jh)->b_state); 621 /* 622 * akpm: jbd2_journal_write_metadata_buffer() sets 623 * new_bh->b_transaction to commit_transaction. 624 * We need to clean this up before we release new_bh 625 * (which is of type BJ_IO) 626 */ 627 JBUFFER_TRACE(jh, "ph3: write metadata"); 628 flags = jbd2_journal_write_metadata_buffer(commit_transaction, 629 jh, &new_jh, blocknr); 630 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state); 631 wbuf[bufs++] = jh2bh(new_jh); 632 633 /* Record the new block's tag in the current descriptor 634 buffer */ 635 636 tag_flag = 0; 637 if (flags & 1) 638 tag_flag |= JBD2_FLAG_ESCAPE; 639 if (!first_tag) 640 tag_flag |= JBD2_FLAG_SAME_UUID; 641 642 tag = (journal_block_tag_t *) tagp; 643 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr); 644 tag->t_flags = cpu_to_be32(tag_flag); 645 tagp += tag_bytes; 646 space_left -= tag_bytes; 647 648 if (first_tag) { 649 memcpy (tagp, journal->j_uuid, 16); 650 tagp += 16; 651 space_left -= 16; 652 first_tag = 0; 653 } 654 655 /* If there's no more to do, or if the descriptor is full, 656 let the IO rip! */ 657 658 if (bufs == journal->j_wbufsize || 659 commit_transaction->t_buffers == NULL || 660 space_left < tag_bytes + 16) { 661 662 jbd_debug(4, "JBD: Submit %d IOs\n", bufs); 663 664 /* Write an end-of-descriptor marker before 665 submitting the IOs. "tag" still points to 666 the last tag we set up. */ 667 668 tag->t_flags |= cpu_to_be32(JBD2_FLAG_LAST_TAG); 669 670 start_journal_io: 671 for (i = 0; i < bufs; i++) { 672 struct buffer_head *bh = wbuf[i]; 673 /* 674 * Compute checksum. 675 */ 676 if (JBD2_HAS_COMPAT_FEATURE(journal, 677 JBD2_FEATURE_COMPAT_CHECKSUM)) { 678 crc32_sum = 679 jbd2_checksum_data(crc32_sum, bh); 680 } 681 682 lock_buffer(bh); 683 clear_buffer_dirty(bh); 684 set_buffer_uptodate(bh); 685 bh->b_end_io = journal_end_buffer_io_sync; 686 submit_bh(write_op, bh); 687 } 688 cond_resched(); 689 stats.u.run.rs_blocks_logged += bufs; 690 691 /* Force a new descriptor to be generated next 692 time round the loop. */ 693 descriptor = NULL; 694 bufs = 0; 695 } 696 } 697 698 /* Done it all: now write the commit record asynchronously. */ 699 700 if (JBD2_HAS_INCOMPAT_FEATURE(journal, 701 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 702 err = journal_submit_commit_record(journal, commit_transaction, 703 &cbh, crc32_sum); 704 if (err) 705 __jbd2_journal_abort_hard(journal); 706 } 707 708 /* 709 * This is the right place to wait for data buffers both for ASYNC 710 * and !ASYNC commit. If commit is ASYNC, we need to wait only after 711 * the commit block went to disk (which happens above). If commit is 712 * SYNC, we need to wait for data buffers before we start writing 713 * commit block, which happens below in such setting. 714 */ 715 err = journal_finish_inode_data_buffers(journal, commit_transaction); 716 if (err) { 717 printk(KERN_WARNING 718 "JBD2: Detected IO errors while flushing file data " 719 "on %s\n", journal->j_devname); 720 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR) 721 jbd2_journal_abort(journal, err); 722 err = 0; 723 } 724 725 /* Lo and behold: we have just managed to send a transaction to 726 the log. Before we can commit it, wait for the IO so far to 727 complete. Control buffers being written are on the 728 transaction's t_log_list queue, and metadata buffers are on 729 the t_iobuf_list queue. 730 731 Wait for the buffers in reverse order. That way we are 732 less likely to be woken up until all IOs have completed, and 733 so we incur less scheduling load. 734 */ 735 736 jbd_debug(3, "JBD: commit phase 3\n"); 737 738 /* 739 * akpm: these are BJ_IO, and j_list_lock is not needed. 740 * See __journal_try_to_free_buffer. 741 */ 742 wait_for_iobuf: 743 while (commit_transaction->t_iobuf_list != NULL) { 744 struct buffer_head *bh; 745 746 jh = commit_transaction->t_iobuf_list->b_tprev; 747 bh = jh2bh(jh); 748 if (buffer_locked(bh)) { 749 wait_on_buffer(bh); 750 goto wait_for_iobuf; 751 } 752 if (cond_resched()) 753 goto wait_for_iobuf; 754 755 if (unlikely(!buffer_uptodate(bh))) 756 err = -EIO; 757 758 clear_buffer_jwrite(bh); 759 760 JBUFFER_TRACE(jh, "ph4: unfile after journal write"); 761 jbd2_journal_unfile_buffer(journal, jh); 762 763 /* 764 * ->t_iobuf_list should contain only dummy buffer_heads 765 * which were created by jbd2_journal_write_metadata_buffer(). 766 */ 767 BUFFER_TRACE(bh, "dumping temporary bh"); 768 jbd2_journal_put_journal_head(jh); 769 __brelse(bh); 770 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); 771 free_buffer_head(bh); 772 773 /* We also have to unlock and free the corresponding 774 shadowed buffer */ 775 jh = commit_transaction->t_shadow_list->b_tprev; 776 bh = jh2bh(jh); 777 clear_bit(BH_JWrite, &bh->b_state); 778 J_ASSERT_BH(bh, buffer_jbddirty(bh)); 779 780 /* The metadata is now released for reuse, but we need 781 to remember it against this transaction so that when 782 we finally commit, we can do any checkpointing 783 required. */ 784 JBUFFER_TRACE(jh, "file as BJ_Forget"); 785 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget); 786 /* Wake up any transactions which were waiting for this 787 IO to complete */ 788 wake_up_bit(&bh->b_state, BH_Unshadow); 789 JBUFFER_TRACE(jh, "brelse shadowed buffer"); 790 __brelse(bh); 791 } 792 793 J_ASSERT (commit_transaction->t_shadow_list == NULL); 794 795 jbd_debug(3, "JBD: commit phase 4\n"); 796 797 /* Here we wait for the revoke record and descriptor record buffers */ 798 wait_for_ctlbuf: 799 while (commit_transaction->t_log_list != NULL) { 800 struct buffer_head *bh; 801 802 jh = commit_transaction->t_log_list->b_tprev; 803 bh = jh2bh(jh); 804 if (buffer_locked(bh)) { 805 wait_on_buffer(bh); 806 goto wait_for_ctlbuf; 807 } 808 if (cond_resched()) 809 goto wait_for_ctlbuf; 810 811 if (unlikely(!buffer_uptodate(bh))) 812 err = -EIO; 813 814 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); 815 clear_buffer_jwrite(bh); 816 jbd2_journal_unfile_buffer(journal, jh); 817 jbd2_journal_put_journal_head(jh); 818 __brelse(bh); /* One for getblk */ 819 /* AKPM: bforget here */ 820 } 821 822 if (err) 823 jbd2_journal_abort(journal, err); 824 825 jbd_debug(3, "JBD: commit phase 5\n"); 826 827 if (!JBD2_HAS_INCOMPAT_FEATURE(journal, 828 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 829 err = journal_submit_commit_record(journal, commit_transaction, 830 &cbh, crc32_sum); 831 if (err) 832 __jbd2_journal_abort_hard(journal); 833 } 834 if (!err && !is_journal_aborted(journal)) 835 err = journal_wait_on_commit_record(journal, cbh); 836 837 if (err) 838 jbd2_journal_abort(journal, err); 839 840 /* End of a transaction! Finally, we can do checkpoint 841 processing: any buffers committed as a result of this 842 transaction can be removed from any checkpoint list it was on 843 before. */ 844 845 jbd_debug(3, "JBD: commit phase 6\n"); 846 847 J_ASSERT(list_empty(&commit_transaction->t_inode_list)); 848 J_ASSERT(commit_transaction->t_buffers == NULL); 849 J_ASSERT(commit_transaction->t_checkpoint_list == NULL); 850 J_ASSERT(commit_transaction->t_iobuf_list == NULL); 851 J_ASSERT(commit_transaction->t_shadow_list == NULL); 852 J_ASSERT(commit_transaction->t_log_list == NULL); 853 854 restart_loop: 855 /* 856 * As there are other places (journal_unmap_buffer()) adding buffers 857 * to this list we have to be careful and hold the j_list_lock. 858 */ 859 spin_lock(&journal->j_list_lock); 860 while (commit_transaction->t_forget) { 861 transaction_t *cp_transaction; 862 struct buffer_head *bh; 863 864 jh = commit_transaction->t_forget; 865 spin_unlock(&journal->j_list_lock); 866 bh = jh2bh(jh); 867 jbd_lock_bh_state(bh); 868 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction || 869 jh->b_transaction == journal->j_running_transaction); 870 871 /* 872 * If there is undo-protected committed data against 873 * this buffer, then we can remove it now. If it is a 874 * buffer needing such protection, the old frozen_data 875 * field now points to a committed version of the 876 * buffer, so rotate that field to the new committed 877 * data. 878 * 879 * Otherwise, we can just throw away the frozen data now. 880 * 881 * We also know that the frozen data has already fired 882 * its triggers if they exist, so we can clear that too. 883 */ 884 if (jh->b_committed_data) { 885 jbd2_free(jh->b_committed_data, bh->b_size); 886 jh->b_committed_data = NULL; 887 if (jh->b_frozen_data) { 888 jh->b_committed_data = jh->b_frozen_data; 889 jh->b_frozen_data = NULL; 890 jh->b_frozen_triggers = NULL; 891 } 892 } else if (jh->b_frozen_data) { 893 jbd2_free(jh->b_frozen_data, bh->b_size); 894 jh->b_frozen_data = NULL; 895 jh->b_frozen_triggers = NULL; 896 } 897 898 spin_lock(&journal->j_list_lock); 899 cp_transaction = jh->b_cp_transaction; 900 if (cp_transaction) { 901 JBUFFER_TRACE(jh, "remove from old cp transaction"); 902 cp_transaction->t_chp_stats.cs_dropped++; 903 __jbd2_journal_remove_checkpoint(jh); 904 } 905 906 /* Only re-checkpoint the buffer_head if it is marked 907 * dirty. If the buffer was added to the BJ_Forget list 908 * by jbd2_journal_forget, it may no longer be dirty and 909 * there's no point in keeping a checkpoint record for 910 * it. */ 911 912 /* A buffer which has been freed while still being 913 * journaled by a previous transaction may end up still 914 * being dirty here, but we want to avoid writing back 915 * that buffer in the future now that the last use has 916 * been committed. That's not only a performance gain, 917 * it also stops aliasing problems if the buffer is left 918 * behind for writeback and gets reallocated for another 919 * use in a different page. */ 920 if (buffer_freed(bh)) { 921 clear_buffer_freed(bh); 922 clear_buffer_jbddirty(bh); 923 } 924 925 if (buffer_jbddirty(bh)) { 926 JBUFFER_TRACE(jh, "add to new checkpointing trans"); 927 __jbd2_journal_insert_checkpoint(jh, commit_transaction); 928 if (is_journal_aborted(journal)) 929 clear_buffer_jbddirty(bh); 930 JBUFFER_TRACE(jh, "refile for checkpoint writeback"); 931 __jbd2_journal_refile_buffer(jh); 932 jbd_unlock_bh_state(bh); 933 } else { 934 J_ASSERT_BH(bh, !buffer_dirty(bh)); 935 /* The buffer on BJ_Forget list and not jbddirty means 936 * it has been freed by this transaction and hence it 937 * could not have been reallocated until this 938 * transaction has committed. *BUT* it could be 939 * reallocated once we have written all the data to 940 * disk and before we process the buffer on BJ_Forget 941 * list. */ 942 JBUFFER_TRACE(jh, "refile or unfile freed buffer"); 943 __jbd2_journal_refile_buffer(jh); 944 if (!jh->b_transaction) { 945 jbd_unlock_bh_state(bh); 946 /* needs a brelse */ 947 jbd2_journal_remove_journal_head(bh); 948 release_buffer_page(bh); 949 } else 950 jbd_unlock_bh_state(bh); 951 } 952 cond_resched_lock(&journal->j_list_lock); 953 } 954 spin_unlock(&journal->j_list_lock); 955 /* 956 * This is a bit sleazy. We use j_list_lock to protect transition 957 * of a transaction into T_FINISHED state and calling 958 * __jbd2_journal_drop_transaction(). Otherwise we could race with 959 * other checkpointing code processing the transaction... 960 */ 961 spin_lock(&journal->j_state_lock); 962 spin_lock(&journal->j_list_lock); 963 /* 964 * Now recheck if some buffers did not get attached to the transaction 965 * while the lock was dropped... 966 */ 967 if (commit_transaction->t_forget) { 968 spin_unlock(&journal->j_list_lock); 969 spin_unlock(&journal->j_state_lock); 970 goto restart_loop; 971 } 972 973 /* Done with this transaction! */ 974 975 jbd_debug(3, "JBD: commit phase 7\n"); 976 977 J_ASSERT(commit_transaction->t_state == T_COMMIT); 978 979 commit_transaction->t_start = jiffies; 980 stats.u.run.rs_logging = jbd2_time_diff(stats.u.run.rs_logging, 981 commit_transaction->t_start); 982 983 /* 984 * File the transaction for history 985 */ 986 stats.ts_type = JBD2_STATS_RUN; 987 stats.ts_tid = commit_transaction->t_tid; 988 stats.u.run.rs_handle_count = commit_transaction->t_handle_count; 989 spin_lock(&journal->j_history_lock); 990 memcpy(journal->j_history + journal->j_history_cur, &stats, 991 sizeof(stats)); 992 if (++journal->j_history_cur == journal->j_history_max) 993 journal->j_history_cur = 0; 994 995 /* 996 * Calculate overall stats 997 */ 998 journal->j_stats.ts_tid++; 999 journal->j_stats.u.run.rs_wait += stats.u.run.rs_wait; 1000 journal->j_stats.u.run.rs_running += stats.u.run.rs_running; 1001 journal->j_stats.u.run.rs_locked += stats.u.run.rs_locked; 1002 journal->j_stats.u.run.rs_flushing += stats.u.run.rs_flushing; 1003 journal->j_stats.u.run.rs_logging += stats.u.run.rs_logging; 1004 journal->j_stats.u.run.rs_handle_count += stats.u.run.rs_handle_count; 1005 journal->j_stats.u.run.rs_blocks += stats.u.run.rs_blocks; 1006 journal->j_stats.u.run.rs_blocks_logged += stats.u.run.rs_blocks_logged; 1007 spin_unlock(&journal->j_history_lock); 1008 1009 commit_transaction->t_state = T_FINISHED; 1010 J_ASSERT(commit_transaction == journal->j_committing_transaction); 1011 journal->j_commit_sequence = commit_transaction->t_tid; 1012 journal->j_committing_transaction = NULL; 1013 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); 1014 1015 /* 1016 * weight the commit time higher than the average time so we don't 1017 * react too strongly to vast changes in the commit time 1018 */ 1019 if (likely(journal->j_average_commit_time)) 1020 journal->j_average_commit_time = (commit_time + 1021 journal->j_average_commit_time*3) / 4; 1022 else 1023 journal->j_average_commit_time = commit_time; 1024 spin_unlock(&journal->j_state_lock); 1025 1026 if (commit_transaction->t_checkpoint_list == NULL && 1027 commit_transaction->t_checkpoint_io_list == NULL) { 1028 __jbd2_journal_drop_transaction(journal, commit_transaction); 1029 to_free = 1; 1030 } else { 1031 if (journal->j_checkpoint_transactions == NULL) { 1032 journal->j_checkpoint_transactions = commit_transaction; 1033 commit_transaction->t_cpnext = commit_transaction; 1034 commit_transaction->t_cpprev = commit_transaction; 1035 } else { 1036 commit_transaction->t_cpnext = 1037 journal->j_checkpoint_transactions; 1038 commit_transaction->t_cpprev = 1039 commit_transaction->t_cpnext->t_cpprev; 1040 commit_transaction->t_cpnext->t_cpprev = 1041 commit_transaction; 1042 commit_transaction->t_cpprev->t_cpnext = 1043 commit_transaction; 1044 } 1045 } 1046 spin_unlock(&journal->j_list_lock); 1047 1048 if (journal->j_commit_callback) 1049 journal->j_commit_callback(journal, commit_transaction); 1050 1051 trace_mark(jbd2_end_commit, "dev %s transaction %d head %d", 1052 journal->j_devname, commit_transaction->t_tid, 1053 journal->j_tail_sequence); 1054 jbd_debug(1, "JBD: commit %d complete, head %d\n", 1055 journal->j_commit_sequence, journal->j_tail_sequence); 1056 if (to_free) 1057 kfree(commit_transaction); 1058 1059 wake_up(&journal->j_wait_done_commit); 1060 } 1061