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 commit_transaction->t_flushed_data_blocks = 1; 223 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 224 smp_mb__after_clear_bit(); 225 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 226 } 227 spin_unlock(&journal->j_list_lock); 228 return ret; 229 } 230 231 /* 232 * Wait for data submitted for writeout, refile inodes to proper 233 * transaction if needed. 234 * 235 */ 236 static int journal_finish_inode_data_buffers(journal_t *journal, 237 transaction_t *commit_transaction) 238 { 239 struct jbd2_inode *jinode, *next_i; 240 int err, ret = 0; 241 242 /* For locking, see the comment in journal_submit_data_buffers() */ 243 spin_lock(&journal->j_list_lock); 244 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 245 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 246 spin_unlock(&journal->j_list_lock); 247 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping); 248 if (err) { 249 /* 250 * Because AS_EIO is cleared by 251 * filemap_fdatawait_range(), set it again so 252 * that user process can get -EIO from fsync(). 253 */ 254 set_bit(AS_EIO, 255 &jinode->i_vfs_inode->i_mapping->flags); 256 257 if (!ret) 258 ret = err; 259 } 260 spin_lock(&journal->j_list_lock); 261 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 262 smp_mb__after_clear_bit(); 263 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 264 } 265 266 /* Now refile inode to proper lists */ 267 list_for_each_entry_safe(jinode, next_i, 268 &commit_transaction->t_inode_list, i_list) { 269 list_del(&jinode->i_list); 270 if (jinode->i_next_transaction) { 271 jinode->i_transaction = jinode->i_next_transaction; 272 jinode->i_next_transaction = NULL; 273 list_add(&jinode->i_list, 274 &jinode->i_transaction->t_inode_list); 275 } else { 276 jinode->i_transaction = NULL; 277 } 278 } 279 spin_unlock(&journal->j_list_lock); 280 281 return ret; 282 } 283 284 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh) 285 { 286 struct page *page = bh->b_page; 287 char *addr; 288 __u32 checksum; 289 290 addr = kmap_atomic(page, KM_USER0); 291 checksum = crc32_be(crc32_sum, 292 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size); 293 kunmap_atomic(addr, KM_USER0); 294 295 return checksum; 296 } 297 298 static void write_tag_block(int tag_bytes, journal_block_tag_t *tag, 299 unsigned long long block) 300 { 301 tag->t_blocknr = cpu_to_be32(block & (u32)~0); 302 if (tag_bytes > JBD2_TAG_SIZE32) 303 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1); 304 } 305 306 /* 307 * jbd2_journal_commit_transaction 308 * 309 * The primary function for committing a transaction to the log. This 310 * function is called by the journal thread to begin a complete commit. 311 */ 312 void jbd2_journal_commit_transaction(journal_t *journal) 313 { 314 struct transaction_stats_s stats; 315 transaction_t *commit_transaction; 316 struct journal_head *jh, *new_jh, *descriptor; 317 struct buffer_head **wbuf = journal->j_wbuf; 318 int bufs; 319 int flags; 320 int err; 321 unsigned long long blocknr; 322 ktime_t start_time; 323 u64 commit_time; 324 char *tagp = NULL; 325 journal_header_t *header; 326 journal_block_tag_t *tag = NULL; 327 int space_left = 0; 328 int first_tag = 0; 329 int tag_flag; 330 int i, to_free = 0; 331 int tag_bytes = journal_tag_bytes(journal); 332 struct buffer_head *cbh = NULL; /* For transactional checksums */ 333 __u32 crc32_sum = ~0; 334 struct blk_plug plug; 335 336 /* 337 * First job: lock down the current transaction and wait for 338 * all outstanding updates to complete. 339 */ 340 341 #ifdef COMMIT_STATS 342 spin_lock(&journal->j_list_lock); 343 summarise_journal_usage(journal); 344 spin_unlock(&journal->j_list_lock); 345 #endif 346 347 /* Do we need to erase the effects of a prior jbd2_journal_flush? */ 348 if (journal->j_flags & JBD2_FLUSHED) { 349 jbd_debug(3, "super block updated\n"); 350 jbd2_journal_update_superblock(journal, 1); 351 } else { 352 jbd_debug(3, "superblock not updated\n"); 353 } 354 355 J_ASSERT(journal->j_running_transaction != NULL); 356 J_ASSERT(journal->j_committing_transaction == NULL); 357 358 commit_transaction = journal->j_running_transaction; 359 J_ASSERT(commit_transaction->t_state == T_RUNNING); 360 361 trace_jbd2_start_commit(journal, commit_transaction); 362 jbd_debug(1, "JBD: starting commit of transaction %d\n", 363 commit_transaction->t_tid); 364 365 write_lock(&journal->j_state_lock); 366 commit_transaction->t_state = T_LOCKED; 367 368 trace_jbd2_commit_locking(journal, commit_transaction); 369 stats.run.rs_wait = commit_transaction->t_max_wait; 370 stats.run.rs_locked = jiffies; 371 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start, 372 stats.run.rs_locked); 373 374 spin_lock(&commit_transaction->t_handle_lock); 375 while (atomic_read(&commit_transaction->t_updates)) { 376 DEFINE_WAIT(wait); 377 378 prepare_to_wait(&journal->j_wait_updates, &wait, 379 TASK_UNINTERRUPTIBLE); 380 if (atomic_read(&commit_transaction->t_updates)) { 381 spin_unlock(&commit_transaction->t_handle_lock); 382 write_unlock(&journal->j_state_lock); 383 schedule(); 384 write_lock(&journal->j_state_lock); 385 spin_lock(&commit_transaction->t_handle_lock); 386 } 387 finish_wait(&journal->j_wait_updates, &wait); 388 } 389 spin_unlock(&commit_transaction->t_handle_lock); 390 391 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <= 392 journal->j_max_transaction_buffers); 393 394 /* 395 * First thing we are allowed to do is to discard any remaining 396 * BJ_Reserved buffers. Note, it is _not_ permissible to assume 397 * that there are no such buffers: if a large filesystem 398 * operation like a truncate needs to split itself over multiple 399 * transactions, then it may try to do a jbd2_journal_restart() while 400 * there are still BJ_Reserved buffers outstanding. These must 401 * be released cleanly from the current transaction. 402 * 403 * In this case, the filesystem must still reserve write access 404 * again before modifying the buffer in the new transaction, but 405 * we do not require it to remember exactly which old buffers it 406 * has reserved. This is consistent with the existing behaviour 407 * that multiple jbd2_journal_get_write_access() calls to the same 408 * buffer are perfectly permissible. 409 */ 410 while (commit_transaction->t_reserved_list) { 411 jh = commit_transaction->t_reserved_list; 412 JBUFFER_TRACE(jh, "reserved, unused: refile"); 413 /* 414 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may 415 * leave undo-committed data. 416 */ 417 if (jh->b_committed_data) { 418 struct buffer_head *bh = jh2bh(jh); 419 420 jbd_lock_bh_state(bh); 421 jbd2_free(jh->b_committed_data, bh->b_size); 422 jh->b_committed_data = NULL; 423 jbd_unlock_bh_state(bh); 424 } 425 jbd2_journal_refile_buffer(journal, jh); 426 } 427 428 /* 429 * Now try to drop any written-back buffers from the journal's 430 * checkpoint lists. We do this *before* commit because it potentially 431 * frees some memory 432 */ 433 spin_lock(&journal->j_list_lock); 434 __jbd2_journal_clean_checkpoint_list(journal); 435 spin_unlock(&journal->j_list_lock); 436 437 jbd_debug (3, "JBD: commit phase 1\n"); 438 439 /* 440 * Switch to a new revoke table. 441 */ 442 jbd2_journal_switch_revoke_table(journal); 443 444 trace_jbd2_commit_flushing(journal, commit_transaction); 445 stats.run.rs_flushing = jiffies; 446 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked, 447 stats.run.rs_flushing); 448 449 commit_transaction->t_state = T_FLUSH; 450 journal->j_committing_transaction = commit_transaction; 451 journal->j_running_transaction = NULL; 452 start_time = ktime_get(); 453 commit_transaction->t_log_start = journal->j_head; 454 wake_up(&journal->j_wait_transaction_locked); 455 write_unlock(&journal->j_state_lock); 456 457 jbd_debug (3, "JBD: commit phase 2\n"); 458 459 /* 460 * Now start flushing things to disk, in the order they appear 461 * on the transaction lists. Data blocks go first. 462 */ 463 err = journal_submit_data_buffers(journal, commit_transaction); 464 if (err) 465 jbd2_journal_abort(journal, err); 466 467 blk_start_plug(&plug); 468 jbd2_journal_write_revoke_records(journal, commit_transaction, 469 WRITE_SYNC); 470 blk_finish_plug(&plug); 471 472 jbd_debug(3, "JBD: commit phase 2\n"); 473 474 /* 475 * Way to go: we have now written out all of the data for a 476 * transaction! Now comes the tricky part: we need to write out 477 * metadata. Loop over the transaction's entire buffer list: 478 */ 479 write_lock(&journal->j_state_lock); 480 commit_transaction->t_state = T_COMMIT; 481 write_unlock(&journal->j_state_lock); 482 483 trace_jbd2_commit_logging(journal, commit_transaction); 484 stats.run.rs_logging = jiffies; 485 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing, 486 stats.run.rs_logging); 487 stats.run.rs_blocks = 488 atomic_read(&commit_transaction->t_outstanding_credits); 489 stats.run.rs_blocks_logged = 0; 490 491 J_ASSERT(commit_transaction->t_nr_buffers <= 492 atomic_read(&commit_transaction->t_outstanding_credits)); 493 494 err = 0; 495 descriptor = NULL; 496 bufs = 0; 497 blk_start_plug(&plug); 498 while (commit_transaction->t_buffers) { 499 500 /* Find the next buffer to be journaled... */ 501 502 jh = commit_transaction->t_buffers; 503 504 /* If we're in abort mode, we just un-journal the buffer and 505 release it. */ 506 507 if (is_journal_aborted(journal)) { 508 clear_buffer_jbddirty(jh2bh(jh)); 509 JBUFFER_TRACE(jh, "journal is aborting: refile"); 510 jbd2_buffer_abort_trigger(jh, 511 jh->b_frozen_data ? 512 jh->b_frozen_triggers : 513 jh->b_triggers); 514 jbd2_journal_refile_buffer(journal, jh); 515 /* If that was the last one, we need to clean up 516 * any descriptor buffers which may have been 517 * already allocated, even if we are now 518 * aborting. */ 519 if (!commit_transaction->t_buffers) 520 goto start_journal_io; 521 continue; 522 } 523 524 /* Make sure we have a descriptor block in which to 525 record the metadata buffer. */ 526 527 if (!descriptor) { 528 struct buffer_head *bh; 529 530 J_ASSERT (bufs == 0); 531 532 jbd_debug(4, "JBD: get descriptor\n"); 533 534 descriptor = jbd2_journal_get_descriptor_buffer(journal); 535 if (!descriptor) { 536 jbd2_journal_abort(journal, -EIO); 537 continue; 538 } 539 540 bh = jh2bh(descriptor); 541 jbd_debug(4, "JBD: got buffer %llu (%p)\n", 542 (unsigned long long)bh->b_blocknr, bh->b_data); 543 header = (journal_header_t *)&bh->b_data[0]; 544 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); 545 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK); 546 header->h_sequence = cpu_to_be32(commit_transaction->t_tid); 547 548 tagp = &bh->b_data[sizeof(journal_header_t)]; 549 space_left = bh->b_size - sizeof(journal_header_t); 550 first_tag = 1; 551 set_buffer_jwrite(bh); 552 set_buffer_dirty(bh); 553 wbuf[bufs++] = bh; 554 555 /* Record it so that we can wait for IO 556 completion later */ 557 BUFFER_TRACE(bh, "ph3: file as descriptor"); 558 jbd2_journal_file_buffer(descriptor, commit_transaction, 559 BJ_LogCtl); 560 } 561 562 /* Where is the buffer to be written? */ 563 564 err = jbd2_journal_next_log_block(journal, &blocknr); 565 /* If the block mapping failed, just abandon the buffer 566 and repeat this loop: we'll fall into the 567 refile-on-abort condition above. */ 568 if (err) { 569 jbd2_journal_abort(journal, err); 570 continue; 571 } 572 573 /* 574 * start_this_handle() uses t_outstanding_credits to determine 575 * the free space in the log, but this counter is changed 576 * by jbd2_journal_next_log_block() also. 577 */ 578 atomic_dec(&commit_transaction->t_outstanding_credits); 579 580 /* Bump b_count to prevent truncate from stumbling over 581 the shadowed buffer! @@@ This can go if we ever get 582 rid of the BJ_IO/BJ_Shadow pairing of buffers. */ 583 atomic_inc(&jh2bh(jh)->b_count); 584 585 /* Make a temporary IO buffer with which to write it out 586 (this will requeue both the metadata buffer and the 587 temporary IO buffer). new_bh goes on BJ_IO*/ 588 589 set_bit(BH_JWrite, &jh2bh(jh)->b_state); 590 /* 591 * akpm: jbd2_journal_write_metadata_buffer() sets 592 * new_bh->b_transaction to commit_transaction. 593 * We need to clean this up before we release new_bh 594 * (which is of type BJ_IO) 595 */ 596 JBUFFER_TRACE(jh, "ph3: write metadata"); 597 flags = jbd2_journal_write_metadata_buffer(commit_transaction, 598 jh, &new_jh, blocknr); 599 if (flags < 0) { 600 jbd2_journal_abort(journal, flags); 601 continue; 602 } 603 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state); 604 wbuf[bufs++] = jh2bh(new_jh); 605 606 /* Record the new block's tag in the current descriptor 607 buffer */ 608 609 tag_flag = 0; 610 if (flags & 1) 611 tag_flag |= JBD2_FLAG_ESCAPE; 612 if (!first_tag) 613 tag_flag |= JBD2_FLAG_SAME_UUID; 614 615 tag = (journal_block_tag_t *) tagp; 616 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr); 617 tag->t_flags = cpu_to_be32(tag_flag); 618 tagp += tag_bytes; 619 space_left -= tag_bytes; 620 621 if (first_tag) { 622 memcpy (tagp, journal->j_uuid, 16); 623 tagp += 16; 624 space_left -= 16; 625 first_tag = 0; 626 } 627 628 /* If there's no more to do, or if the descriptor is full, 629 let the IO rip! */ 630 631 if (bufs == journal->j_wbufsize || 632 commit_transaction->t_buffers == NULL || 633 space_left < tag_bytes + 16) { 634 635 jbd_debug(4, "JBD: Submit %d IOs\n", bufs); 636 637 /* Write an end-of-descriptor marker before 638 submitting the IOs. "tag" still points to 639 the last tag we set up. */ 640 641 tag->t_flags |= cpu_to_be32(JBD2_FLAG_LAST_TAG); 642 643 start_journal_io: 644 for (i = 0; i < bufs; i++) { 645 struct buffer_head *bh = wbuf[i]; 646 /* 647 * Compute checksum. 648 */ 649 if (JBD2_HAS_COMPAT_FEATURE(journal, 650 JBD2_FEATURE_COMPAT_CHECKSUM)) { 651 crc32_sum = 652 jbd2_checksum_data(crc32_sum, bh); 653 } 654 655 lock_buffer(bh); 656 clear_buffer_dirty(bh); 657 set_buffer_uptodate(bh); 658 bh->b_end_io = journal_end_buffer_io_sync; 659 submit_bh(WRITE_SYNC, bh); 660 } 661 cond_resched(); 662 stats.run.rs_blocks_logged += bufs; 663 664 /* Force a new descriptor to be generated next 665 time round the loop. */ 666 descriptor = NULL; 667 bufs = 0; 668 } 669 } 670 671 err = journal_finish_inode_data_buffers(journal, commit_transaction); 672 if (err) { 673 printk(KERN_WARNING 674 "JBD2: Detected IO errors while flushing file data " 675 "on %s\n", journal->j_devname); 676 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR) 677 jbd2_journal_abort(journal, err); 678 err = 0; 679 } 680 681 /* 682 * If the journal is not located on the file system device, 683 * then we must flush the file system device before we issue 684 * the commit record 685 */ 686 if (commit_transaction->t_flushed_data_blocks && 687 (journal->j_fs_dev != journal->j_dev) && 688 (journal->j_flags & JBD2_BARRIER)) 689 blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL); 690 691 /* Done it all: now write the commit record asynchronously. */ 692 if (JBD2_HAS_INCOMPAT_FEATURE(journal, 693 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 694 err = journal_submit_commit_record(journal, commit_transaction, 695 &cbh, crc32_sum); 696 if (err) 697 __jbd2_journal_abort_hard(journal); 698 } 699 700 blk_finish_plug(&plug); 701 702 /* Lo and behold: we have just managed to send a transaction to 703 the log. Before we can commit it, wait for the IO so far to 704 complete. Control buffers being written are on the 705 transaction's t_log_list queue, and metadata buffers are on 706 the t_iobuf_list queue. 707 708 Wait for the buffers in reverse order. That way we are 709 less likely to be woken up until all IOs have completed, and 710 so we incur less scheduling load. 711 */ 712 713 jbd_debug(3, "JBD: commit phase 3\n"); 714 715 /* 716 * akpm: these are BJ_IO, and j_list_lock is not needed. 717 * See __journal_try_to_free_buffer. 718 */ 719 wait_for_iobuf: 720 while (commit_transaction->t_iobuf_list != NULL) { 721 struct buffer_head *bh; 722 723 jh = commit_transaction->t_iobuf_list->b_tprev; 724 bh = jh2bh(jh); 725 if (buffer_locked(bh)) { 726 wait_on_buffer(bh); 727 goto wait_for_iobuf; 728 } 729 if (cond_resched()) 730 goto wait_for_iobuf; 731 732 if (unlikely(!buffer_uptodate(bh))) 733 err = -EIO; 734 735 clear_buffer_jwrite(bh); 736 737 JBUFFER_TRACE(jh, "ph4: unfile after journal write"); 738 jbd2_journal_unfile_buffer(journal, jh); 739 740 /* 741 * ->t_iobuf_list should contain only dummy buffer_heads 742 * which were created by jbd2_journal_write_metadata_buffer(). 743 */ 744 BUFFER_TRACE(bh, "dumping temporary bh"); 745 jbd2_journal_put_journal_head(jh); 746 __brelse(bh); 747 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); 748 free_buffer_head(bh); 749 750 /* We also have to unlock and free the corresponding 751 shadowed buffer */ 752 jh = commit_transaction->t_shadow_list->b_tprev; 753 bh = jh2bh(jh); 754 clear_bit(BH_JWrite, &bh->b_state); 755 J_ASSERT_BH(bh, buffer_jbddirty(bh)); 756 757 /* The metadata is now released for reuse, but we need 758 to remember it against this transaction so that when 759 we finally commit, we can do any checkpointing 760 required. */ 761 JBUFFER_TRACE(jh, "file as BJ_Forget"); 762 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget); 763 /* Wake up any transactions which were waiting for this 764 IO to complete */ 765 wake_up_bit(&bh->b_state, BH_Unshadow); 766 JBUFFER_TRACE(jh, "brelse shadowed buffer"); 767 __brelse(bh); 768 } 769 770 J_ASSERT (commit_transaction->t_shadow_list == NULL); 771 772 jbd_debug(3, "JBD: commit phase 4\n"); 773 774 /* Here we wait for the revoke record and descriptor record buffers */ 775 wait_for_ctlbuf: 776 while (commit_transaction->t_log_list != NULL) { 777 struct buffer_head *bh; 778 779 jh = commit_transaction->t_log_list->b_tprev; 780 bh = jh2bh(jh); 781 if (buffer_locked(bh)) { 782 wait_on_buffer(bh); 783 goto wait_for_ctlbuf; 784 } 785 if (cond_resched()) 786 goto wait_for_ctlbuf; 787 788 if (unlikely(!buffer_uptodate(bh))) 789 err = -EIO; 790 791 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); 792 clear_buffer_jwrite(bh); 793 jbd2_journal_unfile_buffer(journal, jh); 794 jbd2_journal_put_journal_head(jh); 795 __brelse(bh); /* One for getblk */ 796 /* AKPM: bforget here */ 797 } 798 799 if (err) 800 jbd2_journal_abort(journal, err); 801 802 jbd_debug(3, "JBD: commit phase 5\n"); 803 804 if (!JBD2_HAS_INCOMPAT_FEATURE(journal, 805 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 806 err = journal_submit_commit_record(journal, commit_transaction, 807 &cbh, crc32_sum); 808 if (err) 809 __jbd2_journal_abort_hard(journal); 810 } 811 if (cbh) 812 err = journal_wait_on_commit_record(journal, cbh); 813 if (JBD2_HAS_INCOMPAT_FEATURE(journal, 814 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) && 815 journal->j_flags & JBD2_BARRIER) { 816 blkdev_issue_flush(journal->j_dev, GFP_KERNEL, NULL); 817 } 818 819 if (err) 820 jbd2_journal_abort(journal, err); 821 822 /* End of a transaction! Finally, we can do checkpoint 823 processing: any buffers committed as a result of this 824 transaction can be removed from any checkpoint list it was on 825 before. */ 826 827 jbd_debug(3, "JBD: commit phase 6\n"); 828 829 J_ASSERT(list_empty(&commit_transaction->t_inode_list)); 830 J_ASSERT(commit_transaction->t_buffers == NULL); 831 J_ASSERT(commit_transaction->t_checkpoint_list == NULL); 832 J_ASSERT(commit_transaction->t_iobuf_list == NULL); 833 J_ASSERT(commit_transaction->t_shadow_list == NULL); 834 J_ASSERT(commit_transaction->t_log_list == NULL); 835 836 restart_loop: 837 /* 838 * As there are other places (journal_unmap_buffer()) adding buffers 839 * to this list we have to be careful and hold the j_list_lock. 840 */ 841 spin_lock(&journal->j_list_lock); 842 while (commit_transaction->t_forget) { 843 transaction_t *cp_transaction; 844 struct buffer_head *bh; 845 846 jh = commit_transaction->t_forget; 847 spin_unlock(&journal->j_list_lock); 848 bh = jh2bh(jh); 849 jbd_lock_bh_state(bh); 850 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction); 851 852 /* 853 * If there is undo-protected committed data against 854 * this buffer, then we can remove it now. If it is a 855 * buffer needing such protection, the old frozen_data 856 * field now points to a committed version of the 857 * buffer, so rotate that field to the new committed 858 * data. 859 * 860 * Otherwise, we can just throw away the frozen data now. 861 * 862 * We also know that the frozen data has already fired 863 * its triggers if they exist, so we can clear that too. 864 */ 865 if (jh->b_committed_data) { 866 jbd2_free(jh->b_committed_data, bh->b_size); 867 jh->b_committed_data = NULL; 868 if (jh->b_frozen_data) { 869 jh->b_committed_data = jh->b_frozen_data; 870 jh->b_frozen_data = NULL; 871 jh->b_frozen_triggers = NULL; 872 } 873 } else if (jh->b_frozen_data) { 874 jbd2_free(jh->b_frozen_data, bh->b_size); 875 jh->b_frozen_data = NULL; 876 jh->b_frozen_triggers = NULL; 877 } 878 879 spin_lock(&journal->j_list_lock); 880 cp_transaction = jh->b_cp_transaction; 881 if (cp_transaction) { 882 JBUFFER_TRACE(jh, "remove from old cp transaction"); 883 cp_transaction->t_chp_stats.cs_dropped++; 884 __jbd2_journal_remove_checkpoint(jh); 885 } 886 887 /* Only re-checkpoint the buffer_head if it is marked 888 * dirty. If the buffer was added to the BJ_Forget list 889 * by jbd2_journal_forget, it may no longer be dirty and 890 * there's no point in keeping a checkpoint record for 891 * it. */ 892 893 /* A buffer which has been freed while still being 894 * journaled by a previous transaction may end up still 895 * being dirty here, but we want to avoid writing back 896 * that buffer in the future after the "add to orphan" 897 * operation been committed, That's not only a performance 898 * gain, it also stops aliasing problems if the buffer is 899 * left behind for writeback and gets reallocated for another 900 * use in a different page. */ 901 if (buffer_freed(bh) && !jh->b_next_transaction) { 902 clear_buffer_freed(bh); 903 clear_buffer_jbddirty(bh); 904 } 905 906 if (buffer_jbddirty(bh)) { 907 JBUFFER_TRACE(jh, "add to new checkpointing trans"); 908 __jbd2_journal_insert_checkpoint(jh, commit_transaction); 909 if (is_journal_aborted(journal)) 910 clear_buffer_jbddirty(bh); 911 JBUFFER_TRACE(jh, "refile for checkpoint writeback"); 912 __jbd2_journal_refile_buffer(jh); 913 jbd_unlock_bh_state(bh); 914 } else { 915 J_ASSERT_BH(bh, !buffer_dirty(bh)); 916 /* The buffer on BJ_Forget list and not jbddirty means 917 * it has been freed by this transaction and hence it 918 * could not have been reallocated until this 919 * transaction has committed. *BUT* it could be 920 * reallocated once we have written all the data to 921 * disk and before we process the buffer on BJ_Forget 922 * list. */ 923 JBUFFER_TRACE(jh, "refile or unfile freed buffer"); 924 __jbd2_journal_refile_buffer(jh); 925 if (!jh->b_transaction) { 926 jbd_unlock_bh_state(bh); 927 /* needs a brelse */ 928 jbd2_journal_remove_journal_head(bh); 929 release_buffer_page(bh); 930 } else 931 jbd_unlock_bh_state(bh); 932 } 933 cond_resched_lock(&journal->j_list_lock); 934 } 935 spin_unlock(&journal->j_list_lock); 936 /* 937 * This is a bit sleazy. We use j_list_lock to protect transition 938 * of a transaction into T_FINISHED state and calling 939 * __jbd2_journal_drop_transaction(). Otherwise we could race with 940 * other checkpointing code processing the transaction... 941 */ 942 write_lock(&journal->j_state_lock); 943 spin_lock(&journal->j_list_lock); 944 /* 945 * Now recheck if some buffers did not get attached to the transaction 946 * while the lock was dropped... 947 */ 948 if (commit_transaction->t_forget) { 949 spin_unlock(&journal->j_list_lock); 950 write_unlock(&journal->j_state_lock); 951 goto restart_loop; 952 } 953 954 /* Done with this transaction! */ 955 956 jbd_debug(3, "JBD: commit phase 7\n"); 957 958 J_ASSERT(commit_transaction->t_state == T_COMMIT); 959 960 commit_transaction->t_start = jiffies; 961 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging, 962 commit_transaction->t_start); 963 964 /* 965 * File the transaction statistics 966 */ 967 stats.ts_tid = commit_transaction->t_tid; 968 stats.run.rs_handle_count = 969 atomic_read(&commit_transaction->t_handle_count); 970 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev, 971 commit_transaction->t_tid, &stats.run); 972 973 /* 974 * Calculate overall stats 975 */ 976 spin_lock(&journal->j_history_lock); 977 journal->j_stats.ts_tid++; 978 journal->j_stats.run.rs_wait += stats.run.rs_wait; 979 journal->j_stats.run.rs_running += stats.run.rs_running; 980 journal->j_stats.run.rs_locked += stats.run.rs_locked; 981 journal->j_stats.run.rs_flushing += stats.run.rs_flushing; 982 journal->j_stats.run.rs_logging += stats.run.rs_logging; 983 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count; 984 journal->j_stats.run.rs_blocks += stats.run.rs_blocks; 985 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged; 986 spin_unlock(&journal->j_history_lock); 987 988 commit_transaction->t_state = T_FINISHED; 989 J_ASSERT(commit_transaction == journal->j_committing_transaction); 990 journal->j_commit_sequence = commit_transaction->t_tid; 991 journal->j_committing_transaction = NULL; 992 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); 993 994 /* 995 * weight the commit time higher than the average time so we don't 996 * react too strongly to vast changes in the commit time 997 */ 998 if (likely(journal->j_average_commit_time)) 999 journal->j_average_commit_time = (commit_time + 1000 journal->j_average_commit_time*3) / 4; 1001 else 1002 journal->j_average_commit_time = commit_time; 1003 write_unlock(&journal->j_state_lock); 1004 1005 if (commit_transaction->t_checkpoint_list == NULL && 1006 commit_transaction->t_checkpoint_io_list == NULL) { 1007 __jbd2_journal_drop_transaction(journal, commit_transaction); 1008 to_free = 1; 1009 } else { 1010 if (journal->j_checkpoint_transactions == NULL) { 1011 journal->j_checkpoint_transactions = commit_transaction; 1012 commit_transaction->t_cpnext = commit_transaction; 1013 commit_transaction->t_cpprev = commit_transaction; 1014 } else { 1015 commit_transaction->t_cpnext = 1016 journal->j_checkpoint_transactions; 1017 commit_transaction->t_cpprev = 1018 commit_transaction->t_cpnext->t_cpprev; 1019 commit_transaction->t_cpnext->t_cpprev = 1020 commit_transaction; 1021 commit_transaction->t_cpprev->t_cpnext = 1022 commit_transaction; 1023 } 1024 } 1025 spin_unlock(&journal->j_list_lock); 1026 1027 if (journal->j_commit_callback) 1028 journal->j_commit_callback(journal, commit_transaction); 1029 1030 trace_jbd2_end_commit(journal, commit_transaction); 1031 jbd_debug(1, "JBD: commit %d complete, head %d\n", 1032 journal->j_commit_sequence, journal->j_tail_sequence); 1033 if (to_free) 1034 kfree(commit_transaction); 1035 1036 wake_up(&journal->j_wait_done_commit); 1037 } 1038