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