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 if (is_journal_aborted(journal)) 109 return 0; 110 111 descriptor = jbd2_journal_get_descriptor_buffer(journal); 112 if (!descriptor) 113 return 1; 114 115 bh = jh2bh(descriptor); 116 117 tmp = (struct commit_header *)bh->b_data; 118 tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); 119 tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK); 120 tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid); 121 tmp->h_commit_sec = cpu_to_be64(now.tv_sec); 122 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec); 123 124 if (JBD2_HAS_COMPAT_FEATURE(journal, 125 JBD2_FEATURE_COMPAT_CHECKSUM)) { 126 tmp->h_chksum_type = JBD2_CRC32_CHKSUM; 127 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE; 128 tmp->h_chksum[0] = cpu_to_be32(crc32_sum); 129 } 130 131 JBUFFER_TRACE(descriptor, "submit commit block"); 132 lock_buffer(bh); 133 clear_buffer_dirty(bh); 134 set_buffer_uptodate(bh); 135 bh->b_end_io = journal_end_buffer_io_sync; 136 137 if (journal->j_flags & JBD2_BARRIER && 138 !JBD2_HAS_INCOMPAT_FEATURE(journal, 139 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) 140 ret = submit_bh(WRITE_SYNC_PLUG | WRITE_FLUSH_FUA, bh); 141 else 142 ret = submit_bh(WRITE_SYNC_PLUG, bh); 143 144 *cbh = bh; 145 return ret; 146 } 147 148 /* 149 * This function along with journal_submit_commit_record 150 * allows to write the commit record asynchronously. 151 */ 152 static int journal_wait_on_commit_record(journal_t *journal, 153 struct buffer_head *bh) 154 { 155 int ret = 0; 156 157 clear_buffer_dirty(bh); 158 wait_on_buffer(bh); 159 160 if (unlikely(!buffer_uptodate(bh))) 161 ret = -EIO; 162 put_bh(bh); /* One for getblk() */ 163 jbd2_journal_put_journal_head(bh2jh(bh)); 164 165 return ret; 166 } 167 168 /* 169 * write the filemap data using writepage() address_space_operations. 170 * We don't do block allocation here even for delalloc. We don't 171 * use writepages() because with dealyed allocation we may be doing 172 * block allocation in writepages(). 173 */ 174 static int journal_submit_inode_data_buffers(struct address_space *mapping) 175 { 176 int ret; 177 struct writeback_control wbc = { 178 .sync_mode = WB_SYNC_ALL, 179 .nr_to_write = mapping->nrpages * 2, 180 .range_start = 0, 181 .range_end = i_size_read(mapping->host), 182 }; 183 184 ret = generic_writepages(mapping, &wbc); 185 return ret; 186 } 187 188 /* 189 * Submit all the data buffers of inode associated with the transaction to 190 * disk. 191 * 192 * We are in a committing transaction. Therefore no new inode can be added to 193 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently 194 * operate on from being released while we write out pages. 195 */ 196 static int journal_submit_data_buffers(journal_t *journal, 197 transaction_t *commit_transaction) 198 { 199 struct jbd2_inode *jinode; 200 int err, ret = 0; 201 struct address_space *mapping; 202 203 spin_lock(&journal->j_list_lock); 204 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 205 mapping = jinode->i_vfs_inode->i_mapping; 206 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 207 spin_unlock(&journal->j_list_lock); 208 /* 209 * submit the inode data buffers. We use writepage 210 * instead of writepages. Because writepages can do 211 * block allocation with delalloc. We need to write 212 * only allocated blocks here. 213 */ 214 trace_jbd2_submit_inode_data(jinode->i_vfs_inode); 215 err = journal_submit_inode_data_buffers(mapping); 216 if (!ret) 217 ret = err; 218 spin_lock(&journal->j_list_lock); 219 J_ASSERT(jinode->i_transaction == commit_transaction); 220 commit_transaction->t_flushed_data_blocks = 1; 221 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 222 smp_mb__after_clear_bit(); 223 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 224 } 225 spin_unlock(&journal->j_list_lock); 226 return ret; 227 } 228 229 /* 230 * Wait for data submitted for writeout, refile inodes to proper 231 * transaction if needed. 232 * 233 */ 234 static int journal_finish_inode_data_buffers(journal_t *journal, 235 transaction_t *commit_transaction) 236 { 237 struct jbd2_inode *jinode, *next_i; 238 int err, ret = 0; 239 240 /* For locking, see the comment in journal_submit_data_buffers() */ 241 spin_lock(&journal->j_list_lock); 242 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 243 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 244 spin_unlock(&journal->j_list_lock); 245 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping); 246 if (err) { 247 /* 248 * Because AS_EIO is cleared by 249 * filemap_fdatawait_range(), set it again so 250 * that user process can get -EIO from fsync(). 251 */ 252 set_bit(AS_EIO, 253 &jinode->i_vfs_inode->i_mapping->flags); 254 255 if (!ret) 256 ret = err; 257 } 258 spin_lock(&journal->j_list_lock); 259 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 260 smp_mb__after_clear_bit(); 261 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 262 } 263 264 /* Now refile inode to proper lists */ 265 list_for_each_entry_safe(jinode, next_i, 266 &commit_transaction->t_inode_list, i_list) { 267 list_del(&jinode->i_list); 268 if (jinode->i_next_transaction) { 269 jinode->i_transaction = jinode->i_next_transaction; 270 jinode->i_next_transaction = NULL; 271 list_add(&jinode->i_list, 272 &jinode->i_transaction->t_inode_list); 273 } else { 274 jinode->i_transaction = NULL; 275 } 276 } 277 spin_unlock(&journal->j_list_lock); 278 279 return ret; 280 } 281 282 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh) 283 { 284 struct page *page = bh->b_page; 285 char *addr; 286 __u32 checksum; 287 288 addr = kmap_atomic(page, KM_USER0); 289 checksum = crc32_be(crc32_sum, 290 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size); 291 kunmap_atomic(addr, KM_USER0); 292 293 return checksum; 294 } 295 296 static void write_tag_block(int tag_bytes, journal_block_tag_t *tag, 297 unsigned long long block) 298 { 299 tag->t_blocknr = cpu_to_be32(block & (u32)~0); 300 if (tag_bytes > JBD2_TAG_SIZE32) 301 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1); 302 } 303 304 /* 305 * jbd2_journal_commit_transaction 306 * 307 * The primary function for committing a transaction to the log. This 308 * function is called by the journal thread to begin a complete commit. 309 */ 310 void jbd2_journal_commit_transaction(journal_t *journal) 311 { 312 struct transaction_stats_s stats; 313 transaction_t *commit_transaction; 314 struct journal_head *jh, *new_jh, *descriptor; 315 struct buffer_head **wbuf = journal->j_wbuf; 316 int bufs; 317 int flags; 318 int err; 319 unsigned long long blocknr; 320 ktime_t start_time; 321 u64 commit_time; 322 char *tagp = NULL; 323 journal_header_t *header; 324 journal_block_tag_t *tag = NULL; 325 int space_left = 0; 326 int first_tag = 0; 327 int tag_flag; 328 int i, to_free = 0; 329 int tag_bytes = journal_tag_bytes(journal); 330 struct buffer_head *cbh = NULL; /* For transactional checksums */ 331 __u32 crc32_sum = ~0; 332 int write_op = WRITE_SYNC; 333 334 /* 335 * First job: lock down the current transaction and wait for 336 * all outstanding updates to complete. 337 */ 338 339 #ifdef COMMIT_STATS 340 spin_lock(&journal->j_list_lock); 341 summarise_journal_usage(journal); 342 spin_unlock(&journal->j_list_lock); 343 #endif 344 345 /* Do we need to erase the effects of a prior jbd2_journal_flush? */ 346 if (journal->j_flags & JBD2_FLUSHED) { 347 jbd_debug(3, "super block updated\n"); 348 jbd2_journal_update_superblock(journal, 1); 349 } else { 350 jbd_debug(3, "superblock not updated\n"); 351 } 352 353 J_ASSERT(journal->j_running_transaction != NULL); 354 J_ASSERT(journal->j_committing_transaction == NULL); 355 356 commit_transaction = journal->j_running_transaction; 357 J_ASSERT(commit_transaction->t_state == T_RUNNING); 358 359 trace_jbd2_start_commit(journal, commit_transaction); 360 jbd_debug(1, "JBD: starting commit of transaction %d\n", 361 commit_transaction->t_tid); 362 363 write_lock(&journal->j_state_lock); 364 commit_transaction->t_state = T_LOCKED; 365 366 /* 367 * Use plugged writes here, since we want to submit several before 368 * we unplug the device. We don't do explicit unplugging in here, 369 * instead we rely on sync_buffer() doing the unplug for us. 370 */ 371 if (commit_transaction->t_synchronous_commit) 372 write_op = WRITE_SYNC_PLUG; 373 trace_jbd2_commit_locking(journal, commit_transaction); 374 stats.run.rs_wait = commit_transaction->t_max_wait; 375 stats.run.rs_locked = jiffies; 376 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start, 377 stats.run.rs_locked); 378 379 spin_lock(&commit_transaction->t_handle_lock); 380 while (atomic_read(&commit_transaction->t_updates)) { 381 DEFINE_WAIT(wait); 382 383 prepare_to_wait(&journal->j_wait_updates, &wait, 384 TASK_UNINTERRUPTIBLE); 385 if (atomic_read(&commit_transaction->t_updates)) { 386 spin_unlock(&commit_transaction->t_handle_lock); 387 write_unlock(&journal->j_state_lock); 388 schedule(); 389 write_lock(&journal->j_state_lock); 390 spin_lock(&commit_transaction->t_handle_lock); 391 } 392 finish_wait(&journal->j_wait_updates, &wait); 393 } 394 spin_unlock(&commit_transaction->t_handle_lock); 395 396 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <= 397 journal->j_max_transaction_buffers); 398 399 /* 400 * First thing we are allowed to do is to discard any remaining 401 * BJ_Reserved buffers. Note, it is _not_ permissible to assume 402 * that there are no such buffers: if a large filesystem 403 * operation like a truncate needs to split itself over multiple 404 * transactions, then it may try to do a jbd2_journal_restart() while 405 * there are still BJ_Reserved buffers outstanding. These must 406 * be released cleanly from the current transaction. 407 * 408 * In this case, the filesystem must still reserve write access 409 * again before modifying the buffer in the new transaction, but 410 * we do not require it to remember exactly which old buffers it 411 * has reserved. This is consistent with the existing behaviour 412 * that multiple jbd2_journal_get_write_access() calls to the same 413 * buffer are perfectly permissable. 414 */ 415 while (commit_transaction->t_reserved_list) { 416 jh = commit_transaction->t_reserved_list; 417 JBUFFER_TRACE(jh, "reserved, unused: refile"); 418 /* 419 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may 420 * leave undo-committed data. 421 */ 422 if (jh->b_committed_data) { 423 struct buffer_head *bh = jh2bh(jh); 424 425 jbd_lock_bh_state(bh); 426 jbd2_free(jh->b_committed_data, bh->b_size); 427 jh->b_committed_data = NULL; 428 jbd_unlock_bh_state(bh); 429 } 430 jbd2_journal_refile_buffer(journal, jh); 431 } 432 433 /* 434 * Now try to drop any written-back buffers from the journal's 435 * checkpoint lists. We do this *before* commit because it potentially 436 * frees some memory 437 */ 438 spin_lock(&journal->j_list_lock); 439 __jbd2_journal_clean_checkpoint_list(journal); 440 spin_unlock(&journal->j_list_lock); 441 442 jbd_debug (3, "JBD: commit phase 1\n"); 443 444 /* 445 * Switch to a new revoke table. 446 */ 447 jbd2_journal_switch_revoke_table(journal); 448 449 trace_jbd2_commit_flushing(journal, commit_transaction); 450 stats.run.rs_flushing = jiffies; 451 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked, 452 stats.run.rs_flushing); 453 454 commit_transaction->t_state = T_FLUSH; 455 journal->j_committing_transaction = commit_transaction; 456 journal->j_running_transaction = NULL; 457 start_time = ktime_get(); 458 commit_transaction->t_log_start = journal->j_head; 459 wake_up(&journal->j_wait_transaction_locked); 460 write_unlock(&journal->j_state_lock); 461 462 jbd_debug (3, "JBD: commit phase 2\n"); 463 464 /* 465 * Now start flushing things to disk, in the order they appear 466 * on the transaction lists. Data blocks go first. 467 */ 468 err = journal_submit_data_buffers(journal, commit_transaction); 469 if (err) 470 jbd2_journal_abort(journal, err); 471 472 jbd2_journal_write_revoke_records(journal, commit_transaction, 473 write_op); 474 475 jbd_debug(3, "JBD: commit phase 2\n"); 476 477 /* 478 * Way to go: we have now written out all of the data for a 479 * transaction! Now comes the tricky part: we need to write out 480 * metadata. Loop over the transaction's entire buffer list: 481 */ 482 write_lock(&journal->j_state_lock); 483 commit_transaction->t_state = T_COMMIT; 484 write_unlock(&journal->j_state_lock); 485 486 trace_jbd2_commit_logging(journal, commit_transaction); 487 stats.run.rs_logging = jiffies; 488 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing, 489 stats.run.rs_logging); 490 stats.run.rs_blocks = 491 atomic_read(&commit_transaction->t_outstanding_credits); 492 stats.run.rs_blocks_logged = 0; 493 494 J_ASSERT(commit_transaction->t_nr_buffers <= 495 atomic_read(&commit_transaction->t_outstanding_credits)); 496 497 err = 0; 498 descriptor = NULL; 499 bufs = 0; 500 while (commit_transaction->t_buffers) { 501 502 /* Find the next buffer to be journaled... */ 503 504 jh = commit_transaction->t_buffers; 505 506 /* If we're in abort mode, we just un-journal the buffer and 507 release it. */ 508 509 if (is_journal_aborted(journal)) { 510 clear_buffer_jbddirty(jh2bh(jh)); 511 JBUFFER_TRACE(jh, "journal is aborting: refile"); 512 jbd2_buffer_abort_trigger(jh, 513 jh->b_frozen_data ? 514 jh->b_frozen_triggers : 515 jh->b_triggers); 516 jbd2_journal_refile_buffer(journal, jh); 517 /* If that was the last one, we need to clean up 518 * any descriptor buffers which may have been 519 * already allocated, even if we are now 520 * aborting. */ 521 if (!commit_transaction->t_buffers) 522 goto start_journal_io; 523 continue; 524 } 525 526 /* Make sure we have a descriptor block in which to 527 record the metadata buffer. */ 528 529 if (!descriptor) { 530 struct buffer_head *bh; 531 532 J_ASSERT (bufs == 0); 533 534 jbd_debug(4, "JBD: get descriptor\n"); 535 536 descriptor = jbd2_journal_get_descriptor_buffer(journal); 537 if (!descriptor) { 538 jbd2_journal_abort(journal, -EIO); 539 continue; 540 } 541 542 bh = jh2bh(descriptor); 543 jbd_debug(4, "JBD: got buffer %llu (%p)\n", 544 (unsigned long long)bh->b_blocknr, bh->b_data); 545 header = (journal_header_t *)&bh->b_data[0]; 546 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); 547 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK); 548 header->h_sequence = cpu_to_be32(commit_transaction->t_tid); 549 550 tagp = &bh->b_data[sizeof(journal_header_t)]; 551 space_left = bh->b_size - sizeof(journal_header_t); 552 first_tag = 1; 553 set_buffer_jwrite(bh); 554 set_buffer_dirty(bh); 555 wbuf[bufs++] = bh; 556 557 /* Record it so that we can wait for IO 558 completion later */ 559 BUFFER_TRACE(bh, "ph3: file as descriptor"); 560 jbd2_journal_file_buffer(descriptor, commit_transaction, 561 BJ_LogCtl); 562 } 563 564 /* Where is the buffer to be written? */ 565 566 err = jbd2_journal_next_log_block(journal, &blocknr); 567 /* If the block mapping failed, just abandon the buffer 568 and repeat this loop: we'll fall into the 569 refile-on-abort condition above. */ 570 if (err) { 571 jbd2_journal_abort(journal, err); 572 continue; 573 } 574 575 /* 576 * start_this_handle() uses t_outstanding_credits to determine 577 * the free space in the log, but this counter is changed 578 * by jbd2_journal_next_log_block() also. 579 */ 580 atomic_dec(&commit_transaction->t_outstanding_credits); 581 582 /* Bump b_count to prevent truncate from stumbling over 583 the shadowed buffer! @@@ This can go if we ever get 584 rid of the BJ_IO/BJ_Shadow pairing of buffers. */ 585 atomic_inc(&jh2bh(jh)->b_count); 586 587 /* Make a temporary IO buffer with which to write it out 588 (this will requeue both the metadata buffer and the 589 temporary IO buffer). new_bh goes on BJ_IO*/ 590 591 set_bit(BH_JWrite, &jh2bh(jh)->b_state); 592 /* 593 * akpm: jbd2_journal_write_metadata_buffer() sets 594 * new_bh->b_transaction to commit_transaction. 595 * We need to clean this up before we release new_bh 596 * (which is of type BJ_IO) 597 */ 598 JBUFFER_TRACE(jh, "ph3: write metadata"); 599 flags = jbd2_journal_write_metadata_buffer(commit_transaction, 600 jh, &new_jh, blocknr); 601 if (flags < 0) { 602 jbd2_journal_abort(journal, flags); 603 continue; 604 } 605 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state); 606 wbuf[bufs++] = jh2bh(new_jh); 607 608 /* Record the new block's tag in the current descriptor 609 buffer */ 610 611 tag_flag = 0; 612 if (flags & 1) 613 tag_flag |= JBD2_FLAG_ESCAPE; 614 if (!first_tag) 615 tag_flag |= JBD2_FLAG_SAME_UUID; 616 617 tag = (journal_block_tag_t *) tagp; 618 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr); 619 tag->t_flags = cpu_to_be32(tag_flag); 620 tagp += tag_bytes; 621 space_left -= tag_bytes; 622 623 if (first_tag) { 624 memcpy (tagp, journal->j_uuid, 16); 625 tagp += 16; 626 space_left -= 16; 627 first_tag = 0; 628 } 629 630 /* If there's no more to do, or if the descriptor is full, 631 let the IO rip! */ 632 633 if (bufs == journal->j_wbufsize || 634 commit_transaction->t_buffers == NULL || 635 space_left < tag_bytes + 16) { 636 637 jbd_debug(4, "JBD: Submit %d IOs\n", bufs); 638 639 /* Write an end-of-descriptor marker before 640 submitting the IOs. "tag" still points to 641 the last tag we set up. */ 642 643 tag->t_flags |= cpu_to_be32(JBD2_FLAG_LAST_TAG); 644 645 start_journal_io: 646 for (i = 0; i < bufs; i++) { 647 struct buffer_head *bh = wbuf[i]; 648 /* 649 * Compute checksum. 650 */ 651 if (JBD2_HAS_COMPAT_FEATURE(journal, 652 JBD2_FEATURE_COMPAT_CHECKSUM)) { 653 crc32_sum = 654 jbd2_checksum_data(crc32_sum, bh); 655 } 656 657 lock_buffer(bh); 658 clear_buffer_dirty(bh); 659 set_buffer_uptodate(bh); 660 bh->b_end_io = journal_end_buffer_io_sync; 661 submit_bh(write_op, bh); 662 } 663 cond_resched(); 664 stats.run.rs_blocks_logged += bufs; 665 666 /* Force a new descriptor to be generated next 667 time round the loop. */ 668 descriptor = NULL; 669 bufs = 0; 670 } 671 } 672 673 err = journal_finish_inode_data_buffers(journal, commit_transaction); 674 if (err) { 675 printk(KERN_WARNING 676 "JBD2: Detected IO errors while flushing file data " 677 "on %s\n", journal->j_devname); 678 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR) 679 jbd2_journal_abort(journal, err); 680 err = 0; 681 } 682 683 /* 684 * If the journal is not located on the file system device, 685 * then we must flush the file system device before we issue 686 * the commit record 687 */ 688 if (commit_transaction->t_flushed_data_blocks && 689 (journal->j_fs_dev != journal->j_dev) && 690 (journal->j_flags & JBD2_BARRIER)) 691 blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL); 692 693 /* Done it all: now write the commit record asynchronously. */ 694 if (JBD2_HAS_INCOMPAT_FEATURE(journal, 695 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 696 err = journal_submit_commit_record(journal, commit_transaction, 697 &cbh, crc32_sum); 698 if (err) 699 __jbd2_journal_abort_hard(journal); 700 } 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 (!err && !is_journal_aborted(journal)) 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