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_PLUG, 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_PLUG, 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_PLUG, 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 /* 406 * Use plugged writes here, since we want to submit several before 407 * we unplug the device. We don't do explicit unplugging in here, 408 * instead we rely on sync_buffer() doing the unplug for us. 409 */ 410 if (commit_transaction->t_synchronous_commit) 411 write_op = WRITE_SYNC_PLUG; 412 stats.u.run.rs_wait = commit_transaction->t_max_wait; 413 stats.u.run.rs_locked = jiffies; 414 stats.u.run.rs_running = jbd2_time_diff(commit_transaction->t_start, 415 stats.u.run.rs_locked); 416 417 spin_lock(&commit_transaction->t_handle_lock); 418 while (commit_transaction->t_updates) { 419 DEFINE_WAIT(wait); 420 421 prepare_to_wait(&journal->j_wait_updates, &wait, 422 TASK_UNINTERRUPTIBLE); 423 if (commit_transaction->t_updates) { 424 spin_unlock(&commit_transaction->t_handle_lock); 425 spin_unlock(&journal->j_state_lock); 426 schedule(); 427 spin_lock(&journal->j_state_lock); 428 spin_lock(&commit_transaction->t_handle_lock); 429 } 430 finish_wait(&journal->j_wait_updates, &wait); 431 } 432 spin_unlock(&commit_transaction->t_handle_lock); 433 434 J_ASSERT (commit_transaction->t_outstanding_credits <= 435 journal->j_max_transaction_buffers); 436 437 /* 438 * First thing we are allowed to do is to discard any remaining 439 * BJ_Reserved buffers. Note, it is _not_ permissible to assume 440 * that there are no such buffers: if a large filesystem 441 * operation like a truncate needs to split itself over multiple 442 * transactions, then it may try to do a jbd2_journal_restart() while 443 * there are still BJ_Reserved buffers outstanding. These must 444 * be released cleanly from the current transaction. 445 * 446 * In this case, the filesystem must still reserve write access 447 * again before modifying the buffer in the new transaction, but 448 * we do not require it to remember exactly which old buffers it 449 * has reserved. This is consistent with the existing behaviour 450 * that multiple jbd2_journal_get_write_access() calls to the same 451 * buffer are perfectly permissable. 452 */ 453 while (commit_transaction->t_reserved_list) { 454 jh = commit_transaction->t_reserved_list; 455 JBUFFER_TRACE(jh, "reserved, unused: refile"); 456 /* 457 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may 458 * leave undo-committed data. 459 */ 460 if (jh->b_committed_data) { 461 struct buffer_head *bh = jh2bh(jh); 462 463 jbd_lock_bh_state(bh); 464 jbd2_free(jh->b_committed_data, bh->b_size); 465 jh->b_committed_data = NULL; 466 jbd_unlock_bh_state(bh); 467 } 468 jbd2_journal_refile_buffer(journal, jh); 469 } 470 471 /* 472 * Now try to drop any written-back buffers from the journal's 473 * checkpoint lists. We do this *before* commit because it potentially 474 * frees some memory 475 */ 476 spin_lock(&journal->j_list_lock); 477 __jbd2_journal_clean_checkpoint_list(journal); 478 spin_unlock(&journal->j_list_lock); 479 480 jbd_debug (3, "JBD: commit phase 1\n"); 481 482 /* 483 * Switch to a new revoke table. 484 */ 485 jbd2_journal_switch_revoke_table(journal); 486 487 stats.u.run.rs_flushing = jiffies; 488 stats.u.run.rs_locked = jbd2_time_diff(stats.u.run.rs_locked, 489 stats.u.run.rs_flushing); 490 491 commit_transaction->t_state = T_FLUSH; 492 journal->j_committing_transaction = commit_transaction; 493 journal->j_running_transaction = NULL; 494 start_time = ktime_get(); 495 commit_transaction->t_log_start = journal->j_head; 496 wake_up(&journal->j_wait_transaction_locked); 497 spin_unlock(&journal->j_state_lock); 498 499 jbd_debug (3, "JBD: commit phase 2\n"); 500 501 /* 502 * Now start flushing things to disk, in the order they appear 503 * on the transaction lists. Data blocks go first. 504 */ 505 err = journal_submit_data_buffers(journal, commit_transaction); 506 if (err) 507 jbd2_journal_abort(journal, err); 508 509 jbd2_journal_write_revoke_records(journal, commit_transaction, 510 write_op); 511 512 jbd_debug(3, "JBD: commit phase 2\n"); 513 514 /* 515 * Way to go: we have now written out all of the data for a 516 * transaction! Now comes the tricky part: we need to write out 517 * metadata. Loop over the transaction's entire buffer list: 518 */ 519 spin_lock(&journal->j_state_lock); 520 commit_transaction->t_state = T_COMMIT; 521 spin_unlock(&journal->j_state_lock); 522 523 stats.u.run.rs_logging = jiffies; 524 stats.u.run.rs_flushing = jbd2_time_diff(stats.u.run.rs_flushing, 525 stats.u.run.rs_logging); 526 stats.u.run.rs_blocks = commit_transaction->t_outstanding_credits; 527 stats.u.run.rs_blocks_logged = 0; 528 529 J_ASSERT(commit_transaction->t_nr_buffers <= 530 commit_transaction->t_outstanding_credits); 531 532 err = 0; 533 descriptor = NULL; 534 bufs = 0; 535 while (commit_transaction->t_buffers) { 536 537 /* Find the next buffer to be journaled... */ 538 539 jh = commit_transaction->t_buffers; 540 541 /* If we're in abort mode, we just un-journal the buffer and 542 release it. */ 543 544 if (is_journal_aborted(journal)) { 545 clear_buffer_jbddirty(jh2bh(jh)); 546 JBUFFER_TRACE(jh, "journal is aborting: refile"); 547 jbd2_buffer_abort_trigger(jh, 548 jh->b_frozen_data ? 549 jh->b_frozen_triggers : 550 jh->b_triggers); 551 jbd2_journal_refile_buffer(journal, jh); 552 /* If that was the last one, we need to clean up 553 * any descriptor buffers which may have been 554 * already allocated, even if we are now 555 * aborting. */ 556 if (!commit_transaction->t_buffers) 557 goto start_journal_io; 558 continue; 559 } 560 561 /* Make sure we have a descriptor block in which to 562 record the metadata buffer. */ 563 564 if (!descriptor) { 565 struct buffer_head *bh; 566 567 J_ASSERT (bufs == 0); 568 569 jbd_debug(4, "JBD: get descriptor\n"); 570 571 descriptor = jbd2_journal_get_descriptor_buffer(journal); 572 if (!descriptor) { 573 jbd2_journal_abort(journal, -EIO); 574 continue; 575 } 576 577 bh = jh2bh(descriptor); 578 jbd_debug(4, "JBD: got buffer %llu (%p)\n", 579 (unsigned long long)bh->b_blocknr, bh->b_data); 580 header = (journal_header_t *)&bh->b_data[0]; 581 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); 582 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK); 583 header->h_sequence = cpu_to_be32(commit_transaction->t_tid); 584 585 tagp = &bh->b_data[sizeof(journal_header_t)]; 586 space_left = bh->b_size - sizeof(journal_header_t); 587 first_tag = 1; 588 set_buffer_jwrite(bh); 589 set_buffer_dirty(bh); 590 wbuf[bufs++] = bh; 591 592 /* Record it so that we can wait for IO 593 completion later */ 594 BUFFER_TRACE(bh, "ph3: file as descriptor"); 595 jbd2_journal_file_buffer(descriptor, commit_transaction, 596 BJ_LogCtl); 597 } 598 599 /* Where is the buffer to be written? */ 600 601 err = jbd2_journal_next_log_block(journal, &blocknr); 602 /* If the block mapping failed, just abandon the buffer 603 and repeat this loop: we'll fall into the 604 refile-on-abort condition above. */ 605 if (err) { 606 jbd2_journal_abort(journal, err); 607 continue; 608 } 609 610 /* 611 * start_this_handle() uses t_outstanding_credits to determine 612 * the free space in the log, but this counter is changed 613 * by jbd2_journal_next_log_block() also. 614 */ 615 commit_transaction->t_outstanding_credits--; 616 617 /* Bump b_count to prevent truncate from stumbling over 618 the shadowed buffer! @@@ This can go if we ever get 619 rid of the BJ_IO/BJ_Shadow pairing of buffers. */ 620 atomic_inc(&jh2bh(jh)->b_count); 621 622 /* Make a temporary IO buffer with which to write it out 623 (this will requeue both the metadata buffer and the 624 temporary IO buffer). new_bh goes on BJ_IO*/ 625 626 set_bit(BH_JWrite, &jh2bh(jh)->b_state); 627 /* 628 * akpm: jbd2_journal_write_metadata_buffer() sets 629 * new_bh->b_transaction to commit_transaction. 630 * We need to clean this up before we release new_bh 631 * (which is of type BJ_IO) 632 */ 633 JBUFFER_TRACE(jh, "ph3: write metadata"); 634 flags = jbd2_journal_write_metadata_buffer(commit_transaction, 635 jh, &new_jh, blocknr); 636 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state); 637 wbuf[bufs++] = jh2bh(new_jh); 638 639 /* Record the new block's tag in the current descriptor 640 buffer */ 641 642 tag_flag = 0; 643 if (flags & 1) 644 tag_flag |= JBD2_FLAG_ESCAPE; 645 if (!first_tag) 646 tag_flag |= JBD2_FLAG_SAME_UUID; 647 648 tag = (journal_block_tag_t *) tagp; 649 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr); 650 tag->t_flags = cpu_to_be32(tag_flag); 651 tagp += tag_bytes; 652 space_left -= tag_bytes; 653 654 if (first_tag) { 655 memcpy (tagp, journal->j_uuid, 16); 656 tagp += 16; 657 space_left -= 16; 658 first_tag = 0; 659 } 660 661 /* If there's no more to do, or if the descriptor is full, 662 let the IO rip! */ 663 664 if (bufs == journal->j_wbufsize || 665 commit_transaction->t_buffers == NULL || 666 space_left < tag_bytes + 16) { 667 668 jbd_debug(4, "JBD: Submit %d IOs\n", bufs); 669 670 /* Write an end-of-descriptor marker before 671 submitting the IOs. "tag" still points to 672 the last tag we set up. */ 673 674 tag->t_flags |= cpu_to_be32(JBD2_FLAG_LAST_TAG); 675 676 start_journal_io: 677 for (i = 0; i < bufs; i++) { 678 struct buffer_head *bh = wbuf[i]; 679 /* 680 * Compute checksum. 681 */ 682 if (JBD2_HAS_COMPAT_FEATURE(journal, 683 JBD2_FEATURE_COMPAT_CHECKSUM)) { 684 crc32_sum = 685 jbd2_checksum_data(crc32_sum, bh); 686 } 687 688 lock_buffer(bh); 689 clear_buffer_dirty(bh); 690 set_buffer_uptodate(bh); 691 bh->b_end_io = journal_end_buffer_io_sync; 692 submit_bh(write_op, bh); 693 } 694 cond_resched(); 695 stats.u.run.rs_blocks_logged += bufs; 696 697 /* Force a new descriptor to be generated next 698 time round the loop. */ 699 descriptor = NULL; 700 bufs = 0; 701 } 702 } 703 704 /* Done it all: now write the commit record asynchronously. */ 705 706 if (JBD2_HAS_INCOMPAT_FEATURE(journal, 707 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 708 err = journal_submit_commit_record(journal, commit_transaction, 709 &cbh, crc32_sum); 710 if (err) 711 __jbd2_journal_abort_hard(journal); 712 } 713 714 /* 715 * This is the right place to wait for data buffers both for ASYNC 716 * and !ASYNC commit. If commit is ASYNC, we need to wait only after 717 * the commit block went to disk (which happens above). If commit is 718 * SYNC, we need to wait for data buffers before we start writing 719 * commit block, which happens below in such setting. 720 */ 721 err = journal_finish_inode_data_buffers(journal, commit_transaction); 722 if (err) { 723 printk(KERN_WARNING 724 "JBD2: Detected IO errors while flushing file data " 725 "on %s\n", journal->j_devname); 726 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR) 727 jbd2_journal_abort(journal, err); 728 err = 0; 729 } 730 731 /* Lo and behold: we have just managed to send a transaction to 732 the log. Before we can commit it, wait for the IO so far to 733 complete. Control buffers being written are on the 734 transaction's t_log_list queue, and metadata buffers are on 735 the t_iobuf_list queue. 736 737 Wait for the buffers in reverse order. That way we are 738 less likely to be woken up until all IOs have completed, and 739 so we incur less scheduling load. 740 */ 741 742 jbd_debug(3, "JBD: commit phase 3\n"); 743 744 /* 745 * akpm: these are BJ_IO, and j_list_lock is not needed. 746 * See __journal_try_to_free_buffer. 747 */ 748 wait_for_iobuf: 749 while (commit_transaction->t_iobuf_list != NULL) { 750 struct buffer_head *bh; 751 752 jh = commit_transaction->t_iobuf_list->b_tprev; 753 bh = jh2bh(jh); 754 if (buffer_locked(bh)) { 755 wait_on_buffer(bh); 756 goto wait_for_iobuf; 757 } 758 if (cond_resched()) 759 goto wait_for_iobuf; 760 761 if (unlikely(!buffer_uptodate(bh))) 762 err = -EIO; 763 764 clear_buffer_jwrite(bh); 765 766 JBUFFER_TRACE(jh, "ph4: unfile after journal write"); 767 jbd2_journal_unfile_buffer(journal, jh); 768 769 /* 770 * ->t_iobuf_list should contain only dummy buffer_heads 771 * which were created by jbd2_journal_write_metadata_buffer(). 772 */ 773 BUFFER_TRACE(bh, "dumping temporary bh"); 774 jbd2_journal_put_journal_head(jh); 775 __brelse(bh); 776 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); 777 free_buffer_head(bh); 778 779 /* We also have to unlock and free the corresponding 780 shadowed buffer */ 781 jh = commit_transaction->t_shadow_list->b_tprev; 782 bh = jh2bh(jh); 783 clear_bit(BH_JWrite, &bh->b_state); 784 J_ASSERT_BH(bh, buffer_jbddirty(bh)); 785 786 /* The metadata is now released for reuse, but we need 787 to remember it against this transaction so that when 788 we finally commit, we can do any checkpointing 789 required. */ 790 JBUFFER_TRACE(jh, "file as BJ_Forget"); 791 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget); 792 /* Wake up any transactions which were waiting for this 793 IO to complete */ 794 wake_up_bit(&bh->b_state, BH_Unshadow); 795 JBUFFER_TRACE(jh, "brelse shadowed buffer"); 796 __brelse(bh); 797 } 798 799 J_ASSERT (commit_transaction->t_shadow_list == NULL); 800 801 jbd_debug(3, "JBD: commit phase 4\n"); 802 803 /* Here we wait for the revoke record and descriptor record buffers */ 804 wait_for_ctlbuf: 805 while (commit_transaction->t_log_list != NULL) { 806 struct buffer_head *bh; 807 808 jh = commit_transaction->t_log_list->b_tprev; 809 bh = jh2bh(jh); 810 if (buffer_locked(bh)) { 811 wait_on_buffer(bh); 812 goto wait_for_ctlbuf; 813 } 814 if (cond_resched()) 815 goto wait_for_ctlbuf; 816 817 if (unlikely(!buffer_uptodate(bh))) 818 err = -EIO; 819 820 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); 821 clear_buffer_jwrite(bh); 822 jbd2_journal_unfile_buffer(journal, jh); 823 jbd2_journal_put_journal_head(jh); 824 __brelse(bh); /* One for getblk */ 825 /* AKPM: bforget here */ 826 } 827 828 if (err) 829 jbd2_journal_abort(journal, err); 830 831 jbd_debug(3, "JBD: commit phase 5\n"); 832 833 if (!JBD2_HAS_INCOMPAT_FEATURE(journal, 834 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 835 err = journal_submit_commit_record(journal, commit_transaction, 836 &cbh, crc32_sum); 837 if (err) 838 __jbd2_journal_abort_hard(journal); 839 } 840 if (!err && !is_journal_aborted(journal)) 841 err = journal_wait_on_commit_record(journal, cbh); 842 843 if (err) 844 jbd2_journal_abort(journal, err); 845 846 /* End of a transaction! Finally, we can do checkpoint 847 processing: any buffers committed as a result of this 848 transaction can be removed from any checkpoint list it was on 849 before. */ 850 851 jbd_debug(3, "JBD: commit phase 6\n"); 852 853 J_ASSERT(list_empty(&commit_transaction->t_inode_list)); 854 J_ASSERT(commit_transaction->t_buffers == NULL); 855 J_ASSERT(commit_transaction->t_checkpoint_list == NULL); 856 J_ASSERT(commit_transaction->t_iobuf_list == NULL); 857 J_ASSERT(commit_transaction->t_shadow_list == NULL); 858 J_ASSERT(commit_transaction->t_log_list == NULL); 859 860 restart_loop: 861 /* 862 * As there are other places (journal_unmap_buffer()) adding buffers 863 * to this list we have to be careful and hold the j_list_lock. 864 */ 865 spin_lock(&journal->j_list_lock); 866 while (commit_transaction->t_forget) { 867 transaction_t *cp_transaction; 868 struct buffer_head *bh; 869 870 jh = commit_transaction->t_forget; 871 spin_unlock(&journal->j_list_lock); 872 bh = jh2bh(jh); 873 jbd_lock_bh_state(bh); 874 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction || 875 jh->b_transaction == journal->j_running_transaction); 876 877 /* 878 * If there is undo-protected committed data against 879 * this buffer, then we can remove it now. If it is a 880 * buffer needing such protection, the old frozen_data 881 * field now points to a committed version of the 882 * buffer, so rotate that field to the new committed 883 * data. 884 * 885 * Otherwise, we can just throw away the frozen data now. 886 * 887 * We also know that the frozen data has already fired 888 * its triggers if they exist, so we can clear that too. 889 */ 890 if (jh->b_committed_data) { 891 jbd2_free(jh->b_committed_data, bh->b_size); 892 jh->b_committed_data = NULL; 893 if (jh->b_frozen_data) { 894 jh->b_committed_data = jh->b_frozen_data; 895 jh->b_frozen_data = NULL; 896 jh->b_frozen_triggers = NULL; 897 } 898 } else if (jh->b_frozen_data) { 899 jbd2_free(jh->b_frozen_data, bh->b_size); 900 jh->b_frozen_data = NULL; 901 jh->b_frozen_triggers = NULL; 902 } 903 904 spin_lock(&journal->j_list_lock); 905 cp_transaction = jh->b_cp_transaction; 906 if (cp_transaction) { 907 JBUFFER_TRACE(jh, "remove from old cp transaction"); 908 cp_transaction->t_chp_stats.cs_dropped++; 909 __jbd2_journal_remove_checkpoint(jh); 910 } 911 912 /* Only re-checkpoint the buffer_head if it is marked 913 * dirty. If the buffer was added to the BJ_Forget list 914 * by jbd2_journal_forget, it may no longer be dirty and 915 * there's no point in keeping a checkpoint record for 916 * it. */ 917 918 /* A buffer which has been freed while still being 919 * journaled by a previous transaction may end up still 920 * being dirty here, but we want to avoid writing back 921 * that buffer in the future now that the last use has 922 * been committed. That's not only a performance gain, 923 * it also stops aliasing problems if the buffer is left 924 * behind for writeback and gets reallocated for another 925 * use in a different page. */ 926 if (buffer_freed(bh)) { 927 clear_buffer_freed(bh); 928 clear_buffer_jbddirty(bh); 929 } 930 931 if (buffer_jbddirty(bh)) { 932 JBUFFER_TRACE(jh, "add to new checkpointing trans"); 933 __jbd2_journal_insert_checkpoint(jh, commit_transaction); 934 if (is_journal_aborted(journal)) 935 clear_buffer_jbddirty(bh); 936 JBUFFER_TRACE(jh, "refile for checkpoint writeback"); 937 __jbd2_journal_refile_buffer(jh); 938 jbd_unlock_bh_state(bh); 939 } else { 940 J_ASSERT_BH(bh, !buffer_dirty(bh)); 941 /* The buffer on BJ_Forget list and not jbddirty means 942 * it has been freed by this transaction and hence it 943 * could not have been reallocated until this 944 * transaction has committed. *BUT* it could be 945 * reallocated once we have written all the data to 946 * disk and before we process the buffer on BJ_Forget 947 * list. */ 948 JBUFFER_TRACE(jh, "refile or unfile freed buffer"); 949 __jbd2_journal_refile_buffer(jh); 950 if (!jh->b_transaction) { 951 jbd_unlock_bh_state(bh); 952 /* needs a brelse */ 953 jbd2_journal_remove_journal_head(bh); 954 release_buffer_page(bh); 955 } else 956 jbd_unlock_bh_state(bh); 957 } 958 cond_resched_lock(&journal->j_list_lock); 959 } 960 spin_unlock(&journal->j_list_lock); 961 /* 962 * This is a bit sleazy. We use j_list_lock to protect transition 963 * of a transaction into T_FINISHED state and calling 964 * __jbd2_journal_drop_transaction(). Otherwise we could race with 965 * other checkpointing code processing the transaction... 966 */ 967 spin_lock(&journal->j_state_lock); 968 spin_lock(&journal->j_list_lock); 969 /* 970 * Now recheck if some buffers did not get attached to the transaction 971 * while the lock was dropped... 972 */ 973 if (commit_transaction->t_forget) { 974 spin_unlock(&journal->j_list_lock); 975 spin_unlock(&journal->j_state_lock); 976 goto restart_loop; 977 } 978 979 /* Done with this transaction! */ 980 981 jbd_debug(3, "JBD: commit phase 7\n"); 982 983 J_ASSERT(commit_transaction->t_state == T_COMMIT); 984 985 commit_transaction->t_start = jiffies; 986 stats.u.run.rs_logging = jbd2_time_diff(stats.u.run.rs_logging, 987 commit_transaction->t_start); 988 989 /* 990 * File the transaction for history 991 */ 992 stats.ts_type = JBD2_STATS_RUN; 993 stats.ts_tid = commit_transaction->t_tid; 994 stats.u.run.rs_handle_count = commit_transaction->t_handle_count; 995 spin_lock(&journal->j_history_lock); 996 memcpy(journal->j_history + journal->j_history_cur, &stats, 997 sizeof(stats)); 998 if (++journal->j_history_cur == journal->j_history_max) 999 journal->j_history_cur = 0; 1000 1001 /* 1002 * Calculate overall stats 1003 */ 1004 journal->j_stats.ts_tid++; 1005 journal->j_stats.u.run.rs_wait += stats.u.run.rs_wait; 1006 journal->j_stats.u.run.rs_running += stats.u.run.rs_running; 1007 journal->j_stats.u.run.rs_locked += stats.u.run.rs_locked; 1008 journal->j_stats.u.run.rs_flushing += stats.u.run.rs_flushing; 1009 journal->j_stats.u.run.rs_logging += stats.u.run.rs_logging; 1010 journal->j_stats.u.run.rs_handle_count += stats.u.run.rs_handle_count; 1011 journal->j_stats.u.run.rs_blocks += stats.u.run.rs_blocks; 1012 journal->j_stats.u.run.rs_blocks_logged += stats.u.run.rs_blocks_logged; 1013 spin_unlock(&journal->j_history_lock); 1014 1015 commit_transaction->t_state = T_FINISHED; 1016 J_ASSERT(commit_transaction == journal->j_committing_transaction); 1017 journal->j_commit_sequence = commit_transaction->t_tid; 1018 journal->j_committing_transaction = NULL; 1019 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); 1020 1021 /* 1022 * weight the commit time higher than the average time so we don't 1023 * react too strongly to vast changes in the commit time 1024 */ 1025 if (likely(journal->j_average_commit_time)) 1026 journal->j_average_commit_time = (commit_time + 1027 journal->j_average_commit_time*3) / 4; 1028 else 1029 journal->j_average_commit_time = commit_time; 1030 spin_unlock(&journal->j_state_lock); 1031 1032 if (commit_transaction->t_checkpoint_list == NULL && 1033 commit_transaction->t_checkpoint_io_list == NULL) { 1034 __jbd2_journal_drop_transaction(journal, commit_transaction); 1035 to_free = 1; 1036 } else { 1037 if (journal->j_checkpoint_transactions == NULL) { 1038 journal->j_checkpoint_transactions = commit_transaction; 1039 commit_transaction->t_cpnext = commit_transaction; 1040 commit_transaction->t_cpprev = commit_transaction; 1041 } else { 1042 commit_transaction->t_cpnext = 1043 journal->j_checkpoint_transactions; 1044 commit_transaction->t_cpprev = 1045 commit_transaction->t_cpnext->t_cpprev; 1046 commit_transaction->t_cpnext->t_cpprev = 1047 commit_transaction; 1048 commit_transaction->t_cpprev->t_cpnext = 1049 commit_transaction; 1050 } 1051 } 1052 spin_unlock(&journal->j_list_lock); 1053 1054 if (journal->j_commit_callback) 1055 journal->j_commit_callback(journal, commit_transaction); 1056 1057 trace_mark(jbd2_end_commit, "dev %s transaction %d head %d", 1058 journal->j_devname, commit_transaction->t_tid, 1059 journal->j_tail_sequence); 1060 jbd_debug(1, "JBD: commit %d complete, head %d\n", 1061 journal->j_commit_sequence, journal->j_tail_sequence); 1062 if (to_free) 1063 kfree(commit_transaction); 1064 1065 wake_up(&journal->j_wait_done_commit); 1066 } 1067