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 <trace/events/jbd2.h> 30 31 /* 32 * Default IO end handler for temporary BJ_IO buffer_heads. 33 */ 34 static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate) 35 { 36 BUFFER_TRACE(bh, ""); 37 if (uptodate) 38 set_buffer_uptodate(bh); 39 else 40 clear_buffer_uptodate(bh); 41 unlock_buffer(bh); 42 } 43 44 /* 45 * When an ext4 file is truncated, it is possible that some pages are not 46 * successfully freed, because they are attached to a committing transaction. 47 * After the transaction commits, these pages are left on the LRU, with no 48 * ->mapping, and with attached buffers. These pages are trivially reclaimable 49 * by the VM, but their apparent absence upsets the VM accounting, and it makes 50 * the numbers in /proc/meminfo look odd. 51 * 52 * So here, we have a buffer which has just come off the forget list. Look to 53 * see if we can strip all buffers from the backing page. 54 * 55 * Called under lock_journal(), and possibly under journal_datalist_lock. The 56 * caller provided us with a ref against the buffer, and we drop that here. 57 */ 58 static void release_buffer_page(struct buffer_head *bh) 59 { 60 struct page *page; 61 62 if (buffer_dirty(bh)) 63 goto nope; 64 if (atomic_read(&bh->b_count) != 1) 65 goto nope; 66 page = bh->b_page; 67 if (!page) 68 goto nope; 69 if (page->mapping) 70 goto nope; 71 72 /* OK, it's a truncated page */ 73 if (!trylock_page(page)) 74 goto nope; 75 76 page_cache_get(page); 77 __brelse(bh); 78 try_to_free_buffers(page); 79 unlock_page(page); 80 page_cache_release(page); 81 return; 82 83 nope: 84 __brelse(bh); 85 } 86 87 /* 88 * Done it all: now submit the commit record. We should have 89 * cleaned up our previous buffers by now, so if we are in abort 90 * mode we can now just skip the rest of the journal write 91 * entirely. 92 * 93 * Returns 1 if the journal needs to be aborted or 0 on success 94 */ 95 static int journal_submit_commit_record(journal_t *journal, 96 transaction_t *commit_transaction, 97 struct buffer_head **cbh, 98 __u32 crc32_sum) 99 { 100 struct journal_head *descriptor; 101 struct commit_header *tmp; 102 struct buffer_head *bh; 103 int ret; 104 int barrier_done = 0; 105 struct timespec now = current_kernel_time(); 106 107 if (is_journal_aborted(journal)) 108 return 0; 109 110 descriptor = jbd2_journal_get_descriptor_buffer(journal); 111 if (!descriptor) 112 return 1; 113 114 bh = jh2bh(descriptor); 115 116 tmp = (struct commit_header *)bh->b_data; 117 tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); 118 tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK); 119 tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid); 120 tmp->h_commit_sec = cpu_to_be64(now.tv_sec); 121 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec); 122 123 if (JBD2_HAS_COMPAT_FEATURE(journal, 124 JBD2_FEATURE_COMPAT_CHECKSUM)) { 125 tmp->h_chksum_type = JBD2_CRC32_CHKSUM; 126 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE; 127 tmp->h_chksum[0] = cpu_to_be32(crc32_sum); 128 } 129 130 JBUFFER_TRACE(descriptor, "submit commit block"); 131 lock_buffer(bh); 132 clear_buffer_dirty(bh); 133 set_buffer_uptodate(bh); 134 bh->b_end_io = journal_end_buffer_io_sync; 135 136 if (journal->j_flags & JBD2_BARRIER && 137 !JBD2_HAS_INCOMPAT_FEATURE(journal, 138 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 139 set_buffer_ordered(bh); 140 barrier_done = 1; 141 } 142 ret = submit_bh(WRITE_SYNC_PLUG, bh); 143 if (barrier_done) 144 clear_buffer_ordered(bh); 145 146 /* is it possible for another commit to fail at roughly 147 * the same time as this one? If so, we don't want to 148 * trust the barrier flag in the super, but instead want 149 * to remember if we sent a barrier request 150 */ 151 if (ret == -EOPNOTSUPP && barrier_done) { 152 printk(KERN_WARNING 153 "JBD: barrier-based sync failed on %s - " 154 "disabling barriers\n", journal->j_devname); 155 spin_lock(&journal->j_state_lock); 156 journal->j_flags &= ~JBD2_BARRIER; 157 spin_unlock(&journal->j_state_lock); 158 159 /* And try again, without the barrier */ 160 lock_buffer(bh); 161 set_buffer_uptodate(bh); 162 clear_buffer_dirty(bh); 163 ret = submit_bh(WRITE_SYNC_PLUG, bh); 164 } 165 *cbh = bh; 166 return ret; 167 } 168 169 /* 170 * This function along with journal_submit_commit_record 171 * allows to write the commit record asynchronously. 172 */ 173 static int journal_wait_on_commit_record(journal_t *journal, 174 struct buffer_head *bh) 175 { 176 int ret = 0; 177 178 retry: 179 clear_buffer_dirty(bh); 180 wait_on_buffer(bh); 181 if (buffer_eopnotsupp(bh) && (journal->j_flags & JBD2_BARRIER)) { 182 printk(KERN_WARNING 183 "JBD2: wait_on_commit_record: sync failed on %s - " 184 "disabling barriers\n", journal->j_devname); 185 spin_lock(&journal->j_state_lock); 186 journal->j_flags &= ~JBD2_BARRIER; 187 spin_unlock(&journal->j_state_lock); 188 189 lock_buffer(bh); 190 clear_buffer_dirty(bh); 191 set_buffer_uptodate(bh); 192 bh->b_end_io = journal_end_buffer_io_sync; 193 194 ret = submit_bh(WRITE_SYNC_PLUG, bh); 195 if (ret) { 196 unlock_buffer(bh); 197 return ret; 198 } 199 goto retry; 200 } 201 202 if (unlikely(!buffer_uptodate(bh))) 203 ret = -EIO; 204 put_bh(bh); /* One for getblk() */ 205 jbd2_journal_put_journal_head(bh2jh(bh)); 206 207 return ret; 208 } 209 210 /* 211 * write the filemap data using writepage() address_space_operations. 212 * We don't do block allocation here even for delalloc. We don't 213 * use writepages() because with dealyed allocation we may be doing 214 * block allocation in writepages(). 215 */ 216 static int journal_submit_inode_data_buffers(struct address_space *mapping) 217 { 218 int ret; 219 struct writeback_control wbc = { 220 .sync_mode = WB_SYNC_ALL, 221 .nr_to_write = mapping->nrpages * 2, 222 .range_start = 0, 223 .range_end = i_size_read(mapping->host), 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 trace_jbd2_submit_inode_data(jinode->i_vfs_inode); 257 err = journal_submit_inode_data_buffers(mapping); 258 if (!ret) 259 ret = err; 260 spin_lock(&journal->j_list_lock); 261 J_ASSERT(jinode->i_transaction == commit_transaction); 262 commit_transaction->t_flushed_data_blocks = 1; 263 jinode->i_flags &= ~JI_COMMIT_RUNNING; 264 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 265 } 266 spin_unlock(&journal->j_list_lock); 267 return ret; 268 } 269 270 /* 271 * Wait for data submitted for writeout, refile inodes to proper 272 * transaction if needed. 273 * 274 */ 275 static int journal_finish_inode_data_buffers(journal_t *journal, 276 transaction_t *commit_transaction) 277 { 278 struct jbd2_inode *jinode, *next_i; 279 int err, ret = 0; 280 281 /* For locking, see the comment in journal_submit_data_buffers() */ 282 spin_lock(&journal->j_list_lock); 283 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 284 jinode->i_flags |= JI_COMMIT_RUNNING; 285 spin_unlock(&journal->j_list_lock); 286 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping); 287 if (err) { 288 /* 289 * Because AS_EIO is cleared by 290 * filemap_fdatawait_range(), set it again so 291 * that user process can get -EIO from fsync(). 292 */ 293 set_bit(AS_EIO, 294 &jinode->i_vfs_inode->i_mapping->flags); 295 296 if (!ret) 297 ret = err; 298 } 299 spin_lock(&journal->j_list_lock); 300 jinode->i_flags &= ~JI_COMMIT_RUNNING; 301 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 302 } 303 304 /* Now refile inode to proper lists */ 305 list_for_each_entry_safe(jinode, next_i, 306 &commit_transaction->t_inode_list, i_list) { 307 list_del(&jinode->i_list); 308 if (jinode->i_next_transaction) { 309 jinode->i_transaction = jinode->i_next_transaction; 310 jinode->i_next_transaction = NULL; 311 list_add(&jinode->i_list, 312 &jinode->i_transaction->t_inode_list); 313 } else { 314 jinode->i_transaction = NULL; 315 } 316 } 317 spin_unlock(&journal->j_list_lock); 318 319 return ret; 320 } 321 322 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh) 323 { 324 struct page *page = bh->b_page; 325 char *addr; 326 __u32 checksum; 327 328 addr = kmap_atomic(page, KM_USER0); 329 checksum = crc32_be(crc32_sum, 330 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size); 331 kunmap_atomic(addr, KM_USER0); 332 333 return checksum; 334 } 335 336 static void write_tag_block(int tag_bytes, journal_block_tag_t *tag, 337 unsigned long long block) 338 { 339 tag->t_blocknr = cpu_to_be32(block & (u32)~0); 340 if (tag_bytes > JBD2_TAG_SIZE32) 341 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1); 342 } 343 344 /* 345 * jbd2_journal_commit_transaction 346 * 347 * The primary function for committing a transaction to the log. This 348 * function is called by the journal thread to begin a complete commit. 349 */ 350 void jbd2_journal_commit_transaction(journal_t *journal) 351 { 352 struct transaction_stats_s stats; 353 transaction_t *commit_transaction; 354 struct journal_head *jh, *new_jh, *descriptor; 355 struct buffer_head **wbuf = journal->j_wbuf; 356 int bufs; 357 int flags; 358 int err; 359 unsigned long long blocknr; 360 ktime_t start_time; 361 u64 commit_time; 362 char *tagp = NULL; 363 journal_header_t *header; 364 journal_block_tag_t *tag = NULL; 365 int space_left = 0; 366 int first_tag = 0; 367 int tag_flag; 368 int i, to_free = 0; 369 int tag_bytes = journal_tag_bytes(journal); 370 struct buffer_head *cbh = NULL; /* For transactional checksums */ 371 __u32 crc32_sum = ~0; 372 int write_op = WRITE; 373 374 /* 375 * First job: lock down the current transaction and wait for 376 * all outstanding updates to complete. 377 */ 378 379 #ifdef COMMIT_STATS 380 spin_lock(&journal->j_list_lock); 381 summarise_journal_usage(journal); 382 spin_unlock(&journal->j_list_lock); 383 #endif 384 385 /* Do we need to erase the effects of a prior jbd2_journal_flush? */ 386 if (journal->j_flags & JBD2_FLUSHED) { 387 jbd_debug(3, "super block updated\n"); 388 jbd2_journal_update_superblock(journal, 1); 389 } else { 390 jbd_debug(3, "superblock not updated\n"); 391 } 392 393 J_ASSERT(journal->j_running_transaction != NULL); 394 J_ASSERT(journal->j_committing_transaction == NULL); 395 396 commit_transaction = journal->j_running_transaction; 397 J_ASSERT(commit_transaction->t_state == T_RUNNING); 398 399 trace_jbd2_start_commit(journal, commit_transaction); 400 jbd_debug(1, "JBD: starting commit of transaction %d\n", 401 commit_transaction->t_tid); 402 403 spin_lock(&journal->j_state_lock); 404 commit_transaction->t_state = T_LOCKED; 405 406 /* 407 * Use plugged writes here, since we want to submit several before 408 * we unplug the device. We don't do explicit unplugging in here, 409 * instead we rely on sync_buffer() doing the unplug for us. 410 */ 411 if (commit_transaction->t_synchronous_commit) 412 write_op = WRITE_SYNC_PLUG; 413 trace_jbd2_commit_locking(journal, commit_transaction); 414 stats.run.rs_wait = commit_transaction->t_max_wait; 415 stats.run.rs_locked = jiffies; 416 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start, 417 stats.run.rs_locked); 418 419 spin_lock(&commit_transaction->t_handle_lock); 420 while (commit_transaction->t_updates) { 421 DEFINE_WAIT(wait); 422 423 prepare_to_wait(&journal->j_wait_updates, &wait, 424 TASK_UNINTERRUPTIBLE); 425 if (commit_transaction->t_updates) { 426 spin_unlock(&commit_transaction->t_handle_lock); 427 spin_unlock(&journal->j_state_lock); 428 schedule(); 429 spin_lock(&journal->j_state_lock); 430 spin_lock(&commit_transaction->t_handle_lock); 431 } 432 finish_wait(&journal->j_wait_updates, &wait); 433 } 434 spin_unlock(&commit_transaction->t_handle_lock); 435 436 J_ASSERT (commit_transaction->t_outstanding_credits <= 437 journal->j_max_transaction_buffers); 438 439 /* 440 * First thing we are allowed to do is to discard any remaining 441 * BJ_Reserved buffers. Note, it is _not_ permissible to assume 442 * that there are no such buffers: if a large filesystem 443 * operation like a truncate needs to split itself over multiple 444 * transactions, then it may try to do a jbd2_journal_restart() while 445 * there are still BJ_Reserved buffers outstanding. These must 446 * be released cleanly from the current transaction. 447 * 448 * In this case, the filesystem must still reserve write access 449 * again before modifying the buffer in the new transaction, but 450 * we do not require it to remember exactly which old buffers it 451 * has reserved. This is consistent with the existing behaviour 452 * that multiple jbd2_journal_get_write_access() calls to the same 453 * buffer are perfectly permissable. 454 */ 455 while (commit_transaction->t_reserved_list) { 456 jh = commit_transaction->t_reserved_list; 457 JBUFFER_TRACE(jh, "reserved, unused: refile"); 458 /* 459 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may 460 * leave undo-committed data. 461 */ 462 if (jh->b_committed_data) { 463 struct buffer_head *bh = jh2bh(jh); 464 465 jbd_lock_bh_state(bh); 466 jbd2_free(jh->b_committed_data, bh->b_size); 467 jh->b_committed_data = NULL; 468 jbd_unlock_bh_state(bh); 469 } 470 jbd2_journal_refile_buffer(journal, jh); 471 } 472 473 /* 474 * Now try to drop any written-back buffers from the journal's 475 * checkpoint lists. We do this *before* commit because it potentially 476 * frees some memory 477 */ 478 spin_lock(&journal->j_list_lock); 479 __jbd2_journal_clean_checkpoint_list(journal); 480 spin_unlock(&journal->j_list_lock); 481 482 jbd_debug (3, "JBD: commit phase 1\n"); 483 484 /* 485 * Switch to a new revoke table. 486 */ 487 jbd2_journal_switch_revoke_table(journal); 488 489 trace_jbd2_commit_flushing(journal, commit_transaction); 490 stats.run.rs_flushing = jiffies; 491 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked, 492 stats.run.rs_flushing); 493 494 commit_transaction->t_state = T_FLUSH; 495 journal->j_committing_transaction = commit_transaction; 496 journal->j_running_transaction = NULL; 497 start_time = ktime_get(); 498 commit_transaction->t_log_start = journal->j_head; 499 wake_up(&journal->j_wait_transaction_locked); 500 spin_unlock(&journal->j_state_lock); 501 502 jbd_debug (3, "JBD: commit phase 2\n"); 503 504 /* 505 * Now start flushing things to disk, in the order they appear 506 * on the transaction lists. Data blocks go first. 507 */ 508 err = journal_submit_data_buffers(journal, commit_transaction); 509 if (err) 510 jbd2_journal_abort(journal, err); 511 512 jbd2_journal_write_revoke_records(journal, commit_transaction, 513 write_op); 514 515 jbd_debug(3, "JBD: commit phase 2\n"); 516 517 /* 518 * Way to go: we have now written out all of the data for a 519 * transaction! Now comes the tricky part: we need to write out 520 * metadata. Loop over the transaction's entire buffer list: 521 */ 522 spin_lock(&journal->j_state_lock); 523 commit_transaction->t_state = T_COMMIT; 524 spin_unlock(&journal->j_state_lock); 525 526 trace_jbd2_commit_logging(journal, commit_transaction); 527 stats.run.rs_logging = jiffies; 528 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing, 529 stats.run.rs_logging); 530 stats.run.rs_blocks = commit_transaction->t_outstanding_credits; 531 stats.run.rs_blocks_logged = 0; 532 533 J_ASSERT(commit_transaction->t_nr_buffers <= 534 commit_transaction->t_outstanding_credits); 535 536 err = 0; 537 descriptor = NULL; 538 bufs = 0; 539 while (commit_transaction->t_buffers) { 540 541 /* Find the next buffer to be journaled... */ 542 543 jh = commit_transaction->t_buffers; 544 545 /* If we're in abort mode, we just un-journal the buffer and 546 release it. */ 547 548 if (is_journal_aborted(journal)) { 549 clear_buffer_jbddirty(jh2bh(jh)); 550 JBUFFER_TRACE(jh, "journal is aborting: refile"); 551 jbd2_buffer_abort_trigger(jh, 552 jh->b_frozen_data ? 553 jh->b_frozen_triggers : 554 jh->b_triggers); 555 jbd2_journal_refile_buffer(journal, jh); 556 /* If that was the last one, we need to clean up 557 * any descriptor buffers which may have been 558 * already allocated, even if we are now 559 * aborting. */ 560 if (!commit_transaction->t_buffers) 561 goto start_journal_io; 562 continue; 563 } 564 565 /* Make sure we have a descriptor block in which to 566 record the metadata buffer. */ 567 568 if (!descriptor) { 569 struct buffer_head *bh; 570 571 J_ASSERT (bufs == 0); 572 573 jbd_debug(4, "JBD: get descriptor\n"); 574 575 descriptor = jbd2_journal_get_descriptor_buffer(journal); 576 if (!descriptor) { 577 jbd2_journal_abort(journal, -EIO); 578 continue; 579 } 580 581 bh = jh2bh(descriptor); 582 jbd_debug(4, "JBD: got buffer %llu (%p)\n", 583 (unsigned long long)bh->b_blocknr, bh->b_data); 584 header = (journal_header_t *)&bh->b_data[0]; 585 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); 586 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK); 587 header->h_sequence = cpu_to_be32(commit_transaction->t_tid); 588 589 tagp = &bh->b_data[sizeof(journal_header_t)]; 590 space_left = bh->b_size - sizeof(journal_header_t); 591 first_tag = 1; 592 set_buffer_jwrite(bh); 593 set_buffer_dirty(bh); 594 wbuf[bufs++] = bh; 595 596 /* Record it so that we can wait for IO 597 completion later */ 598 BUFFER_TRACE(bh, "ph3: file as descriptor"); 599 jbd2_journal_file_buffer(descriptor, commit_transaction, 600 BJ_LogCtl); 601 } 602 603 /* Where is the buffer to be written? */ 604 605 err = jbd2_journal_next_log_block(journal, &blocknr); 606 /* If the block mapping failed, just abandon the buffer 607 and repeat this loop: we'll fall into the 608 refile-on-abort condition above. */ 609 if (err) { 610 jbd2_journal_abort(journal, err); 611 continue; 612 } 613 614 /* 615 * start_this_handle() uses t_outstanding_credits to determine 616 * the free space in the log, but this counter is changed 617 * by jbd2_journal_next_log_block() also. 618 */ 619 commit_transaction->t_outstanding_credits--; 620 621 /* Bump b_count to prevent truncate from stumbling over 622 the shadowed buffer! @@@ This can go if we ever get 623 rid of the BJ_IO/BJ_Shadow pairing of buffers. */ 624 atomic_inc(&jh2bh(jh)->b_count); 625 626 /* Make a temporary IO buffer with which to write it out 627 (this will requeue both the metadata buffer and the 628 temporary IO buffer). new_bh goes on BJ_IO*/ 629 630 set_bit(BH_JWrite, &jh2bh(jh)->b_state); 631 /* 632 * akpm: jbd2_journal_write_metadata_buffer() sets 633 * new_bh->b_transaction to commit_transaction. 634 * We need to clean this up before we release new_bh 635 * (which is of type BJ_IO) 636 */ 637 JBUFFER_TRACE(jh, "ph3: write metadata"); 638 flags = jbd2_journal_write_metadata_buffer(commit_transaction, 639 jh, &new_jh, blocknr); 640 if (flags < 0) { 641 jbd2_journal_abort(journal, flags); 642 continue; 643 } 644 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state); 645 wbuf[bufs++] = jh2bh(new_jh); 646 647 /* Record the new block's tag in the current descriptor 648 buffer */ 649 650 tag_flag = 0; 651 if (flags & 1) 652 tag_flag |= JBD2_FLAG_ESCAPE; 653 if (!first_tag) 654 tag_flag |= JBD2_FLAG_SAME_UUID; 655 656 tag = (journal_block_tag_t *) tagp; 657 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr); 658 tag->t_flags = cpu_to_be32(tag_flag); 659 tagp += tag_bytes; 660 space_left -= tag_bytes; 661 662 if (first_tag) { 663 memcpy (tagp, journal->j_uuid, 16); 664 tagp += 16; 665 space_left -= 16; 666 first_tag = 0; 667 } 668 669 /* If there's no more to do, or if the descriptor is full, 670 let the IO rip! */ 671 672 if (bufs == journal->j_wbufsize || 673 commit_transaction->t_buffers == NULL || 674 space_left < tag_bytes + 16) { 675 676 jbd_debug(4, "JBD: Submit %d IOs\n", bufs); 677 678 /* Write an end-of-descriptor marker before 679 submitting the IOs. "tag" still points to 680 the last tag we set up. */ 681 682 tag->t_flags |= cpu_to_be32(JBD2_FLAG_LAST_TAG); 683 684 start_journal_io: 685 for (i = 0; i < bufs; i++) { 686 struct buffer_head *bh = wbuf[i]; 687 /* 688 * Compute checksum. 689 */ 690 if (JBD2_HAS_COMPAT_FEATURE(journal, 691 JBD2_FEATURE_COMPAT_CHECKSUM)) { 692 crc32_sum = 693 jbd2_checksum_data(crc32_sum, bh); 694 } 695 696 lock_buffer(bh); 697 clear_buffer_dirty(bh); 698 set_buffer_uptodate(bh); 699 bh->b_end_io = journal_end_buffer_io_sync; 700 submit_bh(write_op, bh); 701 } 702 cond_resched(); 703 stats.run.rs_blocks_logged += bufs; 704 705 /* Force a new descriptor to be generated next 706 time round the loop. */ 707 descriptor = NULL; 708 bufs = 0; 709 } 710 } 711 712 /* 713 * If the journal is not located on the file system device, 714 * then we must flush the file system device before we issue 715 * the commit record 716 */ 717 if (commit_transaction->t_flushed_data_blocks && 718 (journal->j_fs_dev != journal->j_dev) && 719 (journal->j_flags & JBD2_BARRIER)) 720 blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL, 721 BLKDEV_IFL_WAIT); 722 723 /* Done it all: now write the commit record asynchronously. */ 724 if (JBD2_HAS_INCOMPAT_FEATURE(journal, 725 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 726 err = journal_submit_commit_record(journal, commit_transaction, 727 &cbh, crc32_sum); 728 if (err) 729 __jbd2_journal_abort_hard(journal); 730 if (journal->j_flags & JBD2_BARRIER) 731 blkdev_issue_flush(journal->j_dev, GFP_KERNEL, NULL, 732 BLKDEV_IFL_WAIT); 733 } 734 735 err = journal_finish_inode_data_buffers(journal, commit_transaction); 736 if (err) { 737 printk(KERN_WARNING 738 "JBD2: Detected IO errors while flushing file data " 739 "on %s\n", journal->j_devname); 740 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR) 741 jbd2_journal_abort(journal, err); 742 err = 0; 743 } 744 745 /* Lo and behold: we have just managed to send a transaction to 746 the log. Before we can commit it, wait for the IO so far to 747 complete. Control buffers being written are on the 748 transaction's t_log_list queue, and metadata buffers are on 749 the t_iobuf_list queue. 750 751 Wait for the buffers in reverse order. That way we are 752 less likely to be woken up until all IOs have completed, and 753 so we incur less scheduling load. 754 */ 755 756 jbd_debug(3, "JBD: commit phase 3\n"); 757 758 /* 759 * akpm: these are BJ_IO, and j_list_lock is not needed. 760 * See __journal_try_to_free_buffer. 761 */ 762 wait_for_iobuf: 763 while (commit_transaction->t_iobuf_list != NULL) { 764 struct buffer_head *bh; 765 766 jh = commit_transaction->t_iobuf_list->b_tprev; 767 bh = jh2bh(jh); 768 if (buffer_locked(bh)) { 769 wait_on_buffer(bh); 770 goto wait_for_iobuf; 771 } 772 if (cond_resched()) 773 goto wait_for_iobuf; 774 775 if (unlikely(!buffer_uptodate(bh))) 776 err = -EIO; 777 778 clear_buffer_jwrite(bh); 779 780 JBUFFER_TRACE(jh, "ph4: unfile after journal write"); 781 jbd2_journal_unfile_buffer(journal, jh); 782 783 /* 784 * ->t_iobuf_list should contain only dummy buffer_heads 785 * which were created by jbd2_journal_write_metadata_buffer(). 786 */ 787 BUFFER_TRACE(bh, "dumping temporary bh"); 788 jbd2_journal_put_journal_head(jh); 789 __brelse(bh); 790 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); 791 free_buffer_head(bh); 792 793 /* We also have to unlock and free the corresponding 794 shadowed buffer */ 795 jh = commit_transaction->t_shadow_list->b_tprev; 796 bh = jh2bh(jh); 797 clear_bit(BH_JWrite, &bh->b_state); 798 J_ASSERT_BH(bh, buffer_jbddirty(bh)); 799 800 /* The metadata is now released for reuse, but we need 801 to remember it against this transaction so that when 802 we finally commit, we can do any checkpointing 803 required. */ 804 JBUFFER_TRACE(jh, "file as BJ_Forget"); 805 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget); 806 /* Wake up any transactions which were waiting for this 807 IO to complete */ 808 wake_up_bit(&bh->b_state, BH_Unshadow); 809 JBUFFER_TRACE(jh, "brelse shadowed buffer"); 810 __brelse(bh); 811 } 812 813 J_ASSERT (commit_transaction->t_shadow_list == NULL); 814 815 jbd_debug(3, "JBD: commit phase 4\n"); 816 817 /* Here we wait for the revoke record and descriptor record buffers */ 818 wait_for_ctlbuf: 819 while (commit_transaction->t_log_list != NULL) { 820 struct buffer_head *bh; 821 822 jh = commit_transaction->t_log_list->b_tprev; 823 bh = jh2bh(jh); 824 if (buffer_locked(bh)) { 825 wait_on_buffer(bh); 826 goto wait_for_ctlbuf; 827 } 828 if (cond_resched()) 829 goto wait_for_ctlbuf; 830 831 if (unlikely(!buffer_uptodate(bh))) 832 err = -EIO; 833 834 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); 835 clear_buffer_jwrite(bh); 836 jbd2_journal_unfile_buffer(journal, jh); 837 jbd2_journal_put_journal_head(jh); 838 __brelse(bh); /* One for getblk */ 839 /* AKPM: bforget here */ 840 } 841 842 if (err) 843 jbd2_journal_abort(journal, err); 844 845 jbd_debug(3, "JBD: commit phase 5\n"); 846 847 if (!JBD2_HAS_INCOMPAT_FEATURE(journal, 848 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 849 err = journal_submit_commit_record(journal, commit_transaction, 850 &cbh, crc32_sum); 851 if (err) 852 __jbd2_journal_abort_hard(journal); 853 } 854 if (!err && !is_journal_aborted(journal)) 855 err = journal_wait_on_commit_record(journal, cbh); 856 857 if (err) 858 jbd2_journal_abort(journal, err); 859 860 /* End of a transaction! Finally, we can do checkpoint 861 processing: any buffers committed as a result of this 862 transaction can be removed from any checkpoint list it was on 863 before. */ 864 865 jbd_debug(3, "JBD: commit phase 6\n"); 866 867 J_ASSERT(list_empty(&commit_transaction->t_inode_list)); 868 J_ASSERT(commit_transaction->t_buffers == NULL); 869 J_ASSERT(commit_transaction->t_checkpoint_list == NULL); 870 J_ASSERT(commit_transaction->t_iobuf_list == NULL); 871 J_ASSERT(commit_transaction->t_shadow_list == NULL); 872 J_ASSERT(commit_transaction->t_log_list == NULL); 873 874 restart_loop: 875 /* 876 * As there are other places (journal_unmap_buffer()) adding buffers 877 * to this list we have to be careful and hold the j_list_lock. 878 */ 879 spin_lock(&journal->j_list_lock); 880 while (commit_transaction->t_forget) { 881 transaction_t *cp_transaction; 882 struct buffer_head *bh; 883 884 jh = commit_transaction->t_forget; 885 spin_unlock(&journal->j_list_lock); 886 bh = jh2bh(jh); 887 jbd_lock_bh_state(bh); 888 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction); 889 890 /* 891 * If there is undo-protected committed data against 892 * this buffer, then we can remove it now. If it is a 893 * buffer needing such protection, the old frozen_data 894 * field now points to a committed version of the 895 * buffer, so rotate that field to the new committed 896 * data. 897 * 898 * Otherwise, we can just throw away the frozen data now. 899 * 900 * We also know that the frozen data has already fired 901 * its triggers if they exist, so we can clear that too. 902 */ 903 if (jh->b_committed_data) { 904 jbd2_free(jh->b_committed_data, bh->b_size); 905 jh->b_committed_data = NULL; 906 if (jh->b_frozen_data) { 907 jh->b_committed_data = jh->b_frozen_data; 908 jh->b_frozen_data = NULL; 909 jh->b_frozen_triggers = NULL; 910 } 911 } else if (jh->b_frozen_data) { 912 jbd2_free(jh->b_frozen_data, bh->b_size); 913 jh->b_frozen_data = NULL; 914 jh->b_frozen_triggers = NULL; 915 } 916 917 spin_lock(&journal->j_list_lock); 918 cp_transaction = jh->b_cp_transaction; 919 if (cp_transaction) { 920 JBUFFER_TRACE(jh, "remove from old cp transaction"); 921 cp_transaction->t_chp_stats.cs_dropped++; 922 __jbd2_journal_remove_checkpoint(jh); 923 } 924 925 /* Only re-checkpoint the buffer_head if it is marked 926 * dirty. If the buffer was added to the BJ_Forget list 927 * by jbd2_journal_forget, it may no longer be dirty and 928 * there's no point in keeping a checkpoint record for 929 * it. */ 930 931 /* A buffer which has been freed while still being 932 * journaled by a previous transaction may end up still 933 * being dirty here, but we want to avoid writing back 934 * that buffer in the future after the "add to orphan" 935 * operation been committed, That's not only a performance 936 * gain, it also stops aliasing problems if the buffer is 937 * left behind for writeback and gets reallocated for another 938 * use in a different page. */ 939 if (buffer_freed(bh) && !jh->b_next_transaction) { 940 clear_buffer_freed(bh); 941 clear_buffer_jbddirty(bh); 942 } 943 944 if (buffer_jbddirty(bh)) { 945 JBUFFER_TRACE(jh, "add to new checkpointing trans"); 946 __jbd2_journal_insert_checkpoint(jh, commit_transaction); 947 if (is_journal_aborted(journal)) 948 clear_buffer_jbddirty(bh); 949 JBUFFER_TRACE(jh, "refile for checkpoint writeback"); 950 __jbd2_journal_refile_buffer(jh); 951 jbd_unlock_bh_state(bh); 952 } else { 953 J_ASSERT_BH(bh, !buffer_dirty(bh)); 954 /* The buffer on BJ_Forget list and not jbddirty means 955 * it has been freed by this transaction and hence it 956 * could not have been reallocated until this 957 * transaction has committed. *BUT* it could be 958 * reallocated once we have written all the data to 959 * disk and before we process the buffer on BJ_Forget 960 * list. */ 961 JBUFFER_TRACE(jh, "refile or unfile freed buffer"); 962 __jbd2_journal_refile_buffer(jh); 963 if (!jh->b_transaction) { 964 jbd_unlock_bh_state(bh); 965 /* needs a brelse */ 966 jbd2_journal_remove_journal_head(bh); 967 release_buffer_page(bh); 968 } else 969 jbd_unlock_bh_state(bh); 970 } 971 cond_resched_lock(&journal->j_list_lock); 972 } 973 spin_unlock(&journal->j_list_lock); 974 /* 975 * This is a bit sleazy. We use j_list_lock to protect transition 976 * of a transaction into T_FINISHED state and calling 977 * __jbd2_journal_drop_transaction(). Otherwise we could race with 978 * other checkpointing code processing the transaction... 979 */ 980 spin_lock(&journal->j_state_lock); 981 spin_lock(&journal->j_list_lock); 982 /* 983 * Now recheck if some buffers did not get attached to the transaction 984 * while the lock was dropped... 985 */ 986 if (commit_transaction->t_forget) { 987 spin_unlock(&journal->j_list_lock); 988 spin_unlock(&journal->j_state_lock); 989 goto restart_loop; 990 } 991 992 /* Done with this transaction! */ 993 994 jbd_debug(3, "JBD: commit phase 7\n"); 995 996 J_ASSERT(commit_transaction->t_state == T_COMMIT); 997 998 commit_transaction->t_start = jiffies; 999 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging, 1000 commit_transaction->t_start); 1001 1002 /* 1003 * File the transaction statistics 1004 */ 1005 stats.ts_tid = commit_transaction->t_tid; 1006 stats.run.rs_handle_count = commit_transaction->t_handle_count; 1007 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev, 1008 commit_transaction->t_tid, &stats.run); 1009 1010 /* 1011 * Calculate overall stats 1012 */ 1013 spin_lock(&journal->j_history_lock); 1014 journal->j_stats.ts_tid++; 1015 journal->j_stats.run.rs_wait += stats.run.rs_wait; 1016 journal->j_stats.run.rs_running += stats.run.rs_running; 1017 journal->j_stats.run.rs_locked += stats.run.rs_locked; 1018 journal->j_stats.run.rs_flushing += stats.run.rs_flushing; 1019 journal->j_stats.run.rs_logging += stats.run.rs_logging; 1020 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count; 1021 journal->j_stats.run.rs_blocks += stats.run.rs_blocks; 1022 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged; 1023 spin_unlock(&journal->j_history_lock); 1024 1025 commit_transaction->t_state = T_FINISHED; 1026 J_ASSERT(commit_transaction == journal->j_committing_transaction); 1027 journal->j_commit_sequence = commit_transaction->t_tid; 1028 journal->j_committing_transaction = NULL; 1029 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); 1030 1031 /* 1032 * weight the commit time higher than the average time so we don't 1033 * react too strongly to vast changes in the commit time 1034 */ 1035 if (likely(journal->j_average_commit_time)) 1036 journal->j_average_commit_time = (commit_time + 1037 journal->j_average_commit_time*3) / 4; 1038 else 1039 journal->j_average_commit_time = commit_time; 1040 spin_unlock(&journal->j_state_lock); 1041 1042 if (commit_transaction->t_checkpoint_list == NULL && 1043 commit_transaction->t_checkpoint_io_list == NULL) { 1044 __jbd2_journal_drop_transaction(journal, commit_transaction); 1045 to_free = 1; 1046 } else { 1047 if (journal->j_checkpoint_transactions == NULL) { 1048 journal->j_checkpoint_transactions = commit_transaction; 1049 commit_transaction->t_cpnext = commit_transaction; 1050 commit_transaction->t_cpprev = commit_transaction; 1051 } else { 1052 commit_transaction->t_cpnext = 1053 journal->j_checkpoint_transactions; 1054 commit_transaction->t_cpprev = 1055 commit_transaction->t_cpnext->t_cpprev; 1056 commit_transaction->t_cpnext->t_cpprev = 1057 commit_transaction; 1058 commit_transaction->t_cpprev->t_cpnext = 1059 commit_transaction; 1060 } 1061 } 1062 spin_unlock(&journal->j_list_lock); 1063 1064 if (journal->j_commit_callback) 1065 journal->j_commit_callback(journal, commit_transaction); 1066 1067 trace_jbd2_end_commit(journal, commit_transaction); 1068 jbd_debug(1, "JBD: commit %d complete, head %d\n", 1069 journal->j_commit_sequence, journal->j_tail_sequence); 1070 if (to_free) 1071 kfree(commit_transaction); 1072 1073 wake_up(&journal->j_wait_done_commit); 1074 } 1075