1 /* 2 * linux/fs/jbd2/commit.c 3 * 4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998 5 * 6 * Copyright 1998 Red Hat corp --- All Rights Reserved 7 * 8 * This file is part of the Linux kernel and is made available under 9 * the terms of the GNU General Public License, version 2, or at your 10 * option, any later version, incorporated herein by reference. 11 * 12 * Journal commit routines for the generic filesystem journaling code; 13 * part of the ext2fs journaling system. 14 */ 15 16 #include <linux/time.h> 17 #include <linux/fs.h> 18 #include <linux/jbd2.h> 19 #include <linux/errno.h> 20 #include <linux/slab.h> 21 #include <linux/mm.h> 22 #include <linux/pagemap.h> 23 #include <linux/jiffies.h> 24 #include <linux/crc32.h> 25 #include <linux/writeback.h> 26 #include <linux/backing-dev.h> 27 #include <linux/bio.h> 28 #include <linux/blkdev.h> 29 #include <linux/bitops.h> 30 #include <trace/events/jbd2.h> 31 32 /* 33 * IO end handler for temporary buffer_heads handling writes to the journal. 34 */ 35 static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate) 36 { 37 struct buffer_head *orig_bh = bh->b_private; 38 39 BUFFER_TRACE(bh, ""); 40 if (uptodate) 41 set_buffer_uptodate(bh); 42 else 43 clear_buffer_uptodate(bh); 44 if (orig_bh) { 45 clear_bit_unlock(BH_Shadow, &orig_bh->b_state); 46 smp_mb__after_atomic(); 47 wake_up_bit(&orig_bh->b_state, BH_Shadow); 48 } 49 unlock_buffer(bh); 50 } 51 52 /* 53 * When an ext4 file is truncated, it is possible that some pages are not 54 * successfully freed, because they are attached to a committing transaction. 55 * After the transaction commits, these pages are left on the LRU, with no 56 * ->mapping, and with attached buffers. These pages are trivially reclaimable 57 * by the VM, but their apparent absence upsets the VM accounting, and it makes 58 * the numbers in /proc/meminfo look odd. 59 * 60 * So here, we have a buffer which has just come off the forget list. Look to 61 * see if we can strip all buffers from the backing page. 62 * 63 * Called under lock_journal(), and possibly under journal_datalist_lock. The 64 * caller provided us with a ref against the buffer, and we drop that here. 65 */ 66 static void release_buffer_page(struct buffer_head *bh) 67 { 68 struct page *page; 69 70 if (buffer_dirty(bh)) 71 goto nope; 72 if (atomic_read(&bh->b_count) != 1) 73 goto nope; 74 page = bh->b_page; 75 if (!page) 76 goto nope; 77 if (page->mapping) 78 goto nope; 79 80 /* OK, it's a truncated page */ 81 if (!trylock_page(page)) 82 goto nope; 83 84 get_page(page); 85 __brelse(bh); 86 try_to_free_buffers(page); 87 unlock_page(page); 88 put_page(page); 89 return; 90 91 nope: 92 __brelse(bh); 93 } 94 95 static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh) 96 { 97 struct commit_header *h; 98 __u32 csum; 99 100 if (!jbd2_journal_has_csum_v2or3(j)) 101 return; 102 103 h = (struct commit_header *)(bh->b_data); 104 h->h_chksum_type = 0; 105 h->h_chksum_size = 0; 106 h->h_chksum[0] = 0; 107 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize); 108 h->h_chksum[0] = cpu_to_be32(csum); 109 } 110 111 /* 112 * Done it all: now submit the commit record. We should have 113 * cleaned up our previous buffers by now, so if we are in abort 114 * mode we can now just skip the rest of the journal write 115 * entirely. 116 * 117 * Returns 1 if the journal needs to be aborted or 0 on success 118 */ 119 static int journal_submit_commit_record(journal_t *journal, 120 transaction_t *commit_transaction, 121 struct buffer_head **cbh, 122 __u32 crc32_sum) 123 { 124 struct commit_header *tmp; 125 struct buffer_head *bh; 126 int ret; 127 struct timespec now = current_kernel_time(); 128 129 *cbh = NULL; 130 131 if (is_journal_aborted(journal)) 132 return 0; 133 134 bh = jbd2_journal_get_descriptor_buffer(commit_transaction, 135 JBD2_COMMIT_BLOCK); 136 if (!bh) 137 return 1; 138 139 tmp = (struct commit_header *)bh->b_data; 140 tmp->h_commit_sec = cpu_to_be64(now.tv_sec); 141 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec); 142 143 if (jbd2_has_feature_checksum(journal)) { 144 tmp->h_chksum_type = JBD2_CRC32_CHKSUM; 145 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE; 146 tmp->h_chksum[0] = cpu_to_be32(crc32_sum); 147 } 148 jbd2_commit_block_csum_set(journal, bh); 149 150 BUFFER_TRACE(bh, "submit commit block"); 151 lock_buffer(bh); 152 clear_buffer_dirty(bh); 153 set_buffer_uptodate(bh); 154 bh->b_end_io = journal_end_buffer_io_sync; 155 156 if (journal->j_flags & JBD2_BARRIER && 157 !jbd2_has_feature_async_commit(journal)) 158 ret = submit_bh(WRITE_SYNC | WRITE_FLUSH_FUA, bh); 159 else 160 ret = submit_bh(WRITE_SYNC, bh); 161 162 *cbh = bh; 163 return ret; 164 } 165 166 /* 167 * This function along with journal_submit_commit_record 168 * allows to write the commit record asynchronously. 169 */ 170 static int journal_wait_on_commit_record(journal_t *journal, 171 struct buffer_head *bh) 172 { 173 int ret = 0; 174 175 clear_buffer_dirty(bh); 176 wait_on_buffer(bh); 177 178 if (unlikely(!buffer_uptodate(bh))) 179 ret = -EIO; 180 put_bh(bh); /* One for getblk() */ 181 182 return ret; 183 } 184 185 /* 186 * write the filemap data using writepage() address_space_operations. 187 * We don't do block allocation here even for delalloc. We don't 188 * use writepages() because with dealyed allocation we may be doing 189 * block allocation in writepages(). 190 */ 191 static int journal_submit_inode_data_buffers(struct address_space *mapping) 192 { 193 int ret; 194 struct writeback_control wbc = { 195 .sync_mode = WB_SYNC_ALL, 196 .nr_to_write = mapping->nrpages * 2, 197 .range_start = 0, 198 .range_end = i_size_read(mapping->host), 199 }; 200 201 ret = generic_writepages(mapping, &wbc); 202 return ret; 203 } 204 205 /* 206 * Submit all the data buffers of inode associated with the transaction to 207 * disk. 208 * 209 * We are in a committing transaction. Therefore no new inode can be added to 210 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently 211 * operate on from being released while we write out pages. 212 */ 213 static int journal_submit_data_buffers(journal_t *journal, 214 transaction_t *commit_transaction) 215 { 216 struct jbd2_inode *jinode; 217 int err, ret = 0; 218 struct address_space *mapping; 219 220 spin_lock(&journal->j_list_lock); 221 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 222 mapping = jinode->i_vfs_inode->i_mapping; 223 jinode->i_flags |= JI_COMMIT_RUNNING; 224 spin_unlock(&journal->j_list_lock); 225 /* 226 * submit the inode data buffers. We use writepage 227 * instead of writepages. Because writepages can do 228 * block allocation with delalloc. We need to write 229 * only allocated blocks here. 230 */ 231 trace_jbd2_submit_inode_data(jinode->i_vfs_inode); 232 err = journal_submit_inode_data_buffers(mapping); 233 if (!ret) 234 ret = err; 235 spin_lock(&journal->j_list_lock); 236 J_ASSERT(jinode->i_transaction == commit_transaction); 237 jinode->i_flags &= ~JI_COMMIT_RUNNING; 238 smp_mb(); 239 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 240 } 241 spin_unlock(&journal->j_list_lock); 242 return ret; 243 } 244 245 /* 246 * Wait for data submitted for writeout, refile inodes to proper 247 * transaction if needed. 248 * 249 */ 250 static int journal_finish_inode_data_buffers(journal_t *journal, 251 transaction_t *commit_transaction) 252 { 253 struct jbd2_inode *jinode, *next_i; 254 int err, ret = 0; 255 256 /* For locking, see the comment in journal_submit_data_buffers() */ 257 spin_lock(&journal->j_list_lock); 258 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 259 jinode->i_flags |= JI_COMMIT_RUNNING; 260 spin_unlock(&journal->j_list_lock); 261 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping); 262 if (err) { 263 /* 264 * Because AS_EIO is cleared by 265 * filemap_fdatawait_range(), set it again so 266 * that user process can get -EIO from fsync(). 267 */ 268 set_bit(AS_EIO, 269 &jinode->i_vfs_inode->i_mapping->flags); 270 271 if (!ret) 272 ret = err; 273 } 274 spin_lock(&journal->j_list_lock); 275 jinode->i_flags &= ~JI_COMMIT_RUNNING; 276 smp_mb(); 277 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 278 } 279 280 /* Now refile inode to proper lists */ 281 list_for_each_entry_safe(jinode, next_i, 282 &commit_transaction->t_inode_list, i_list) { 283 list_del(&jinode->i_list); 284 if (jinode->i_next_transaction) { 285 jinode->i_transaction = jinode->i_next_transaction; 286 jinode->i_next_transaction = NULL; 287 list_add(&jinode->i_list, 288 &jinode->i_transaction->t_inode_list); 289 } else { 290 jinode->i_transaction = NULL; 291 } 292 } 293 spin_unlock(&journal->j_list_lock); 294 295 return ret; 296 } 297 298 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh) 299 { 300 struct page *page = bh->b_page; 301 char *addr; 302 __u32 checksum; 303 304 addr = kmap_atomic(page); 305 checksum = crc32_be(crc32_sum, 306 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size); 307 kunmap_atomic(addr); 308 309 return checksum; 310 } 311 312 static void write_tag_block(journal_t *j, journal_block_tag_t *tag, 313 unsigned long long block) 314 { 315 tag->t_blocknr = cpu_to_be32(block & (u32)~0); 316 if (jbd2_has_feature_64bit(j)) 317 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1); 318 } 319 320 static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag, 321 struct buffer_head *bh, __u32 sequence) 322 { 323 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag; 324 struct page *page = bh->b_page; 325 __u8 *addr; 326 __u32 csum32; 327 __be32 seq; 328 329 if (!jbd2_journal_has_csum_v2or3(j)) 330 return; 331 332 seq = cpu_to_be32(sequence); 333 addr = kmap_atomic(page); 334 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq)); 335 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data), 336 bh->b_size); 337 kunmap_atomic(addr); 338 339 if (jbd2_has_feature_csum3(j)) 340 tag3->t_checksum = cpu_to_be32(csum32); 341 else 342 tag->t_checksum = cpu_to_be16(csum32); 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; 355 struct buffer_head *descriptor; 356 struct buffer_head **wbuf = journal->j_wbuf; 357 int bufs; 358 int flags; 359 int err; 360 unsigned long long blocknr; 361 ktime_t start_time; 362 u64 commit_time; 363 char *tagp = NULL; 364 journal_block_tag_t *tag = NULL; 365 int space_left = 0; 366 int first_tag = 0; 367 int tag_flag; 368 int i; 369 int tag_bytes = journal_tag_bytes(journal); 370 struct buffer_head *cbh = NULL; /* For transactional checksums */ 371 __u32 crc32_sum = ~0; 372 struct blk_plug plug; 373 /* Tail of the journal */ 374 unsigned long first_block; 375 tid_t first_tid; 376 int update_tail; 377 int csum_size = 0; 378 LIST_HEAD(io_bufs); 379 LIST_HEAD(log_bufs); 380 381 if (jbd2_journal_has_csum_v2or3(journal)) 382 csum_size = sizeof(struct jbd2_journal_block_tail); 383 384 /* 385 * First job: lock down the current transaction and wait for 386 * all outstanding updates to complete. 387 */ 388 389 /* Do we need to erase the effects of a prior jbd2_journal_flush? */ 390 if (journal->j_flags & JBD2_FLUSHED) { 391 jbd_debug(3, "super block updated\n"); 392 mutex_lock(&journal->j_checkpoint_mutex); 393 /* 394 * We hold j_checkpoint_mutex so tail cannot change under us. 395 * We don't need any special data guarantees for writing sb 396 * since journal is empty and it is ok for write to be 397 * flushed only with transaction commit. 398 */ 399 jbd2_journal_update_sb_log_tail(journal, 400 journal->j_tail_sequence, 401 journal->j_tail, 402 WRITE_SYNC); 403 mutex_unlock(&journal->j_checkpoint_mutex); 404 } else { 405 jbd_debug(3, "superblock not updated\n"); 406 } 407 408 J_ASSERT(journal->j_running_transaction != NULL); 409 J_ASSERT(journal->j_committing_transaction == NULL); 410 411 commit_transaction = journal->j_running_transaction; 412 413 trace_jbd2_start_commit(journal, commit_transaction); 414 jbd_debug(1, "JBD2: starting commit of transaction %d\n", 415 commit_transaction->t_tid); 416 417 write_lock(&journal->j_state_lock); 418 J_ASSERT(commit_transaction->t_state == T_RUNNING); 419 commit_transaction->t_state = T_LOCKED; 420 421 trace_jbd2_commit_locking(journal, commit_transaction); 422 stats.run.rs_wait = commit_transaction->t_max_wait; 423 stats.run.rs_request_delay = 0; 424 stats.run.rs_locked = jiffies; 425 if (commit_transaction->t_requested) 426 stats.run.rs_request_delay = 427 jbd2_time_diff(commit_transaction->t_requested, 428 stats.run.rs_locked); 429 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start, 430 stats.run.rs_locked); 431 432 spin_lock(&commit_transaction->t_handle_lock); 433 while (atomic_read(&commit_transaction->t_updates)) { 434 DEFINE_WAIT(wait); 435 436 prepare_to_wait(&journal->j_wait_updates, &wait, 437 TASK_UNINTERRUPTIBLE); 438 if (atomic_read(&commit_transaction->t_updates)) { 439 spin_unlock(&commit_transaction->t_handle_lock); 440 write_unlock(&journal->j_state_lock); 441 schedule(); 442 write_lock(&journal->j_state_lock); 443 spin_lock(&commit_transaction->t_handle_lock); 444 } 445 finish_wait(&journal->j_wait_updates, &wait); 446 } 447 spin_unlock(&commit_transaction->t_handle_lock); 448 449 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <= 450 journal->j_max_transaction_buffers); 451 452 /* 453 * First thing we are allowed to do is to discard any remaining 454 * BJ_Reserved buffers. Note, it is _not_ permissible to assume 455 * that there are no such buffers: if a large filesystem 456 * operation like a truncate needs to split itself over multiple 457 * transactions, then it may try to do a jbd2_journal_restart() while 458 * there are still BJ_Reserved buffers outstanding. These must 459 * be released cleanly from the current transaction. 460 * 461 * In this case, the filesystem must still reserve write access 462 * again before modifying the buffer in the new transaction, but 463 * we do not require it to remember exactly which old buffers it 464 * has reserved. This is consistent with the existing behaviour 465 * that multiple jbd2_journal_get_write_access() calls to the same 466 * buffer are perfectly permissible. 467 */ 468 while (commit_transaction->t_reserved_list) { 469 jh = commit_transaction->t_reserved_list; 470 JBUFFER_TRACE(jh, "reserved, unused: refile"); 471 /* 472 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may 473 * leave undo-committed data. 474 */ 475 if (jh->b_committed_data) { 476 struct buffer_head *bh = jh2bh(jh); 477 478 jbd_lock_bh_state(bh); 479 jbd2_free(jh->b_committed_data, bh->b_size); 480 jh->b_committed_data = NULL; 481 jbd_unlock_bh_state(bh); 482 } 483 jbd2_journal_refile_buffer(journal, jh); 484 } 485 486 /* 487 * Now try to drop any written-back buffers from the journal's 488 * checkpoint lists. We do this *before* commit because it potentially 489 * frees some memory 490 */ 491 spin_lock(&journal->j_list_lock); 492 __jbd2_journal_clean_checkpoint_list(journal, false); 493 spin_unlock(&journal->j_list_lock); 494 495 jbd_debug(3, "JBD2: commit phase 1\n"); 496 497 /* 498 * Clear revoked flag to reflect there is no revoked buffers 499 * in the next transaction which is going to be started. 500 */ 501 jbd2_clear_buffer_revoked_flags(journal); 502 503 /* 504 * Switch to a new revoke table. 505 */ 506 jbd2_journal_switch_revoke_table(journal); 507 508 /* 509 * Reserved credits cannot be claimed anymore, free them 510 */ 511 atomic_sub(atomic_read(&journal->j_reserved_credits), 512 &commit_transaction->t_outstanding_credits); 513 514 trace_jbd2_commit_flushing(journal, commit_transaction); 515 stats.run.rs_flushing = jiffies; 516 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked, 517 stats.run.rs_flushing); 518 519 commit_transaction->t_state = T_FLUSH; 520 journal->j_committing_transaction = commit_transaction; 521 journal->j_running_transaction = NULL; 522 start_time = ktime_get(); 523 commit_transaction->t_log_start = journal->j_head; 524 wake_up(&journal->j_wait_transaction_locked); 525 write_unlock(&journal->j_state_lock); 526 527 jbd_debug(3, "JBD2: commit phase 2a\n"); 528 529 /* 530 * Now start flushing things to disk, in the order they appear 531 * on the transaction lists. Data blocks go first. 532 */ 533 err = journal_submit_data_buffers(journal, commit_transaction); 534 if (err) 535 jbd2_journal_abort(journal, err); 536 537 blk_start_plug(&plug); 538 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs); 539 540 jbd_debug(3, "JBD2: commit phase 2b\n"); 541 542 /* 543 * Way to go: we have now written out all of the data for a 544 * transaction! Now comes the tricky part: we need to write out 545 * metadata. Loop over the transaction's entire buffer list: 546 */ 547 write_lock(&journal->j_state_lock); 548 commit_transaction->t_state = T_COMMIT; 549 write_unlock(&journal->j_state_lock); 550 551 trace_jbd2_commit_logging(journal, commit_transaction); 552 stats.run.rs_logging = jiffies; 553 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing, 554 stats.run.rs_logging); 555 stats.run.rs_blocks = 556 atomic_read(&commit_transaction->t_outstanding_credits); 557 stats.run.rs_blocks_logged = 0; 558 559 J_ASSERT(commit_transaction->t_nr_buffers <= 560 atomic_read(&commit_transaction->t_outstanding_credits)); 561 562 err = 0; 563 bufs = 0; 564 descriptor = NULL; 565 while (commit_transaction->t_buffers) { 566 567 /* Find the next buffer to be journaled... */ 568 569 jh = commit_transaction->t_buffers; 570 571 /* If we're in abort mode, we just un-journal the buffer and 572 release it. */ 573 574 if (is_journal_aborted(journal)) { 575 clear_buffer_jbddirty(jh2bh(jh)); 576 JBUFFER_TRACE(jh, "journal is aborting: refile"); 577 jbd2_buffer_abort_trigger(jh, 578 jh->b_frozen_data ? 579 jh->b_frozen_triggers : 580 jh->b_triggers); 581 jbd2_journal_refile_buffer(journal, jh); 582 /* If that was the last one, we need to clean up 583 * any descriptor buffers which may have been 584 * already allocated, even if we are now 585 * aborting. */ 586 if (!commit_transaction->t_buffers) 587 goto start_journal_io; 588 continue; 589 } 590 591 /* Make sure we have a descriptor block in which to 592 record the metadata buffer. */ 593 594 if (!descriptor) { 595 J_ASSERT (bufs == 0); 596 597 jbd_debug(4, "JBD2: get descriptor\n"); 598 599 descriptor = jbd2_journal_get_descriptor_buffer( 600 commit_transaction, 601 JBD2_DESCRIPTOR_BLOCK); 602 if (!descriptor) { 603 jbd2_journal_abort(journal, -EIO); 604 continue; 605 } 606 607 jbd_debug(4, "JBD2: got buffer %llu (%p)\n", 608 (unsigned long long)descriptor->b_blocknr, 609 descriptor->b_data); 610 tagp = &descriptor->b_data[sizeof(journal_header_t)]; 611 space_left = descriptor->b_size - 612 sizeof(journal_header_t); 613 first_tag = 1; 614 set_buffer_jwrite(descriptor); 615 set_buffer_dirty(descriptor); 616 wbuf[bufs++] = descriptor; 617 618 /* Record it so that we can wait for IO 619 completion later */ 620 BUFFER_TRACE(descriptor, "ph3: file as descriptor"); 621 jbd2_file_log_bh(&log_bufs, descriptor); 622 } 623 624 /* Where is the buffer to be written? */ 625 626 err = jbd2_journal_next_log_block(journal, &blocknr); 627 /* If the block mapping failed, just abandon the buffer 628 and repeat this loop: we'll fall into the 629 refile-on-abort condition above. */ 630 if (err) { 631 jbd2_journal_abort(journal, err); 632 continue; 633 } 634 635 /* 636 * start_this_handle() uses t_outstanding_credits to determine 637 * the free space in the log, but this counter is changed 638 * by jbd2_journal_next_log_block() also. 639 */ 640 atomic_dec(&commit_transaction->t_outstanding_credits); 641 642 /* Bump b_count to prevent truncate from stumbling over 643 the shadowed buffer! @@@ This can go if we ever get 644 rid of the shadow pairing of buffers. */ 645 atomic_inc(&jh2bh(jh)->b_count); 646 647 /* 648 * Make a temporary IO buffer with which to write it out 649 * (this will requeue the metadata buffer to BJ_Shadow). 650 */ 651 set_bit(BH_JWrite, &jh2bh(jh)->b_state); 652 JBUFFER_TRACE(jh, "ph3: write metadata"); 653 flags = jbd2_journal_write_metadata_buffer(commit_transaction, 654 jh, &wbuf[bufs], blocknr); 655 if (flags < 0) { 656 jbd2_journal_abort(journal, flags); 657 continue; 658 } 659 jbd2_file_log_bh(&io_bufs, wbuf[bufs]); 660 661 /* Record the new block's tag in the current descriptor 662 buffer */ 663 664 tag_flag = 0; 665 if (flags & 1) 666 tag_flag |= JBD2_FLAG_ESCAPE; 667 if (!first_tag) 668 tag_flag |= JBD2_FLAG_SAME_UUID; 669 670 tag = (journal_block_tag_t *) tagp; 671 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr); 672 tag->t_flags = cpu_to_be16(tag_flag); 673 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs], 674 commit_transaction->t_tid); 675 tagp += tag_bytes; 676 space_left -= tag_bytes; 677 bufs++; 678 679 if (first_tag) { 680 memcpy (tagp, journal->j_uuid, 16); 681 tagp += 16; 682 space_left -= 16; 683 first_tag = 0; 684 } 685 686 /* If there's no more to do, or if the descriptor is full, 687 let the IO rip! */ 688 689 if (bufs == journal->j_wbufsize || 690 commit_transaction->t_buffers == NULL || 691 space_left < tag_bytes + 16 + csum_size) { 692 693 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs); 694 695 /* Write an end-of-descriptor marker before 696 submitting the IOs. "tag" still points to 697 the last tag we set up. */ 698 699 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG); 700 701 jbd2_descriptor_block_csum_set(journal, descriptor); 702 start_journal_io: 703 for (i = 0; i < bufs; i++) { 704 struct buffer_head *bh = wbuf[i]; 705 /* 706 * Compute checksum. 707 */ 708 if (jbd2_has_feature_checksum(journal)) { 709 crc32_sum = 710 jbd2_checksum_data(crc32_sum, bh); 711 } 712 713 lock_buffer(bh); 714 clear_buffer_dirty(bh); 715 set_buffer_uptodate(bh); 716 bh->b_end_io = journal_end_buffer_io_sync; 717 submit_bh(WRITE_SYNC, bh); 718 } 719 cond_resched(); 720 stats.run.rs_blocks_logged += bufs; 721 722 /* Force a new descriptor to be generated next 723 time round the loop. */ 724 descriptor = NULL; 725 bufs = 0; 726 } 727 } 728 729 err = journal_finish_inode_data_buffers(journal, commit_transaction); 730 if (err) { 731 printk(KERN_WARNING 732 "JBD2: Detected IO errors while flushing file data " 733 "on %s\n", journal->j_devname); 734 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR) 735 jbd2_journal_abort(journal, err); 736 err = 0; 737 } 738 739 /* 740 * Get current oldest transaction in the log before we issue flush 741 * to the filesystem device. After the flush we can be sure that 742 * blocks of all older transactions are checkpointed to persistent 743 * storage and we will be safe to update journal start in the 744 * superblock with the numbers we get here. 745 */ 746 update_tail = 747 jbd2_journal_get_log_tail(journal, &first_tid, &first_block); 748 749 write_lock(&journal->j_state_lock); 750 if (update_tail) { 751 long freed = first_block - journal->j_tail; 752 753 if (first_block < journal->j_tail) 754 freed += journal->j_last - journal->j_first; 755 /* Update tail only if we free significant amount of space */ 756 if (freed < journal->j_maxlen / 4) 757 update_tail = 0; 758 } 759 J_ASSERT(commit_transaction->t_state == T_COMMIT); 760 commit_transaction->t_state = T_COMMIT_DFLUSH; 761 write_unlock(&journal->j_state_lock); 762 763 /* 764 * If the journal is not located on the file system device, 765 * then we must flush the file system device before we issue 766 * the commit record 767 */ 768 if (commit_transaction->t_need_data_flush && 769 (journal->j_fs_dev != journal->j_dev) && 770 (journal->j_flags & JBD2_BARRIER)) 771 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL); 772 773 /* Done it all: now write the commit record asynchronously. */ 774 if (jbd2_has_feature_async_commit(journal)) { 775 err = journal_submit_commit_record(journal, commit_transaction, 776 &cbh, crc32_sum); 777 if (err) 778 __jbd2_journal_abort_hard(journal); 779 } 780 781 blk_finish_plug(&plug); 782 783 /* Lo and behold: we have just managed to send a transaction to 784 the log. Before we can commit it, wait for the IO so far to 785 complete. Control buffers being written are on the 786 transaction's t_log_list queue, and metadata buffers are on 787 the io_bufs list. 788 789 Wait for the buffers in reverse order. That way we are 790 less likely to be woken up until all IOs have completed, and 791 so we incur less scheduling load. 792 */ 793 794 jbd_debug(3, "JBD2: commit phase 3\n"); 795 796 while (!list_empty(&io_bufs)) { 797 struct buffer_head *bh = list_entry(io_bufs.prev, 798 struct buffer_head, 799 b_assoc_buffers); 800 801 wait_on_buffer(bh); 802 cond_resched(); 803 804 if (unlikely(!buffer_uptodate(bh))) 805 err = -EIO; 806 jbd2_unfile_log_bh(bh); 807 808 /* 809 * The list contains temporary buffer heads created by 810 * jbd2_journal_write_metadata_buffer(). 811 */ 812 BUFFER_TRACE(bh, "dumping temporary bh"); 813 __brelse(bh); 814 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); 815 free_buffer_head(bh); 816 817 /* We also have to refile the corresponding shadowed buffer */ 818 jh = commit_transaction->t_shadow_list->b_tprev; 819 bh = jh2bh(jh); 820 clear_buffer_jwrite(bh); 821 J_ASSERT_BH(bh, buffer_jbddirty(bh)); 822 J_ASSERT_BH(bh, !buffer_shadow(bh)); 823 824 /* The metadata is now released for reuse, but we need 825 to remember it against this transaction so that when 826 we finally commit, we can do any checkpointing 827 required. */ 828 JBUFFER_TRACE(jh, "file as BJ_Forget"); 829 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget); 830 JBUFFER_TRACE(jh, "brelse shadowed buffer"); 831 __brelse(bh); 832 } 833 834 J_ASSERT (commit_transaction->t_shadow_list == NULL); 835 836 jbd_debug(3, "JBD2: commit phase 4\n"); 837 838 /* Here we wait for the revoke record and descriptor record buffers */ 839 while (!list_empty(&log_bufs)) { 840 struct buffer_head *bh; 841 842 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers); 843 wait_on_buffer(bh); 844 cond_resched(); 845 846 if (unlikely(!buffer_uptodate(bh))) 847 err = -EIO; 848 849 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); 850 clear_buffer_jwrite(bh); 851 jbd2_unfile_log_bh(bh); 852 __brelse(bh); /* One for getblk */ 853 /* AKPM: bforget here */ 854 } 855 856 if (err) 857 jbd2_journal_abort(journal, err); 858 859 jbd_debug(3, "JBD2: commit phase 5\n"); 860 write_lock(&journal->j_state_lock); 861 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH); 862 commit_transaction->t_state = T_COMMIT_JFLUSH; 863 write_unlock(&journal->j_state_lock); 864 865 if (!jbd2_has_feature_async_commit(journal)) { 866 err = journal_submit_commit_record(journal, commit_transaction, 867 &cbh, crc32_sum); 868 if (err) 869 __jbd2_journal_abort_hard(journal); 870 } 871 if (cbh) 872 err = journal_wait_on_commit_record(journal, cbh); 873 if (jbd2_has_feature_async_commit(journal) && 874 journal->j_flags & JBD2_BARRIER) { 875 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL); 876 } 877 878 if (err) 879 jbd2_journal_abort(journal, err); 880 881 /* 882 * Now disk caches for filesystem device are flushed so we are safe to 883 * erase checkpointed transactions from the log by updating journal 884 * superblock. 885 */ 886 if (update_tail) 887 jbd2_update_log_tail(journal, first_tid, first_block); 888 889 /* End of a transaction! Finally, we can do checkpoint 890 processing: any buffers committed as a result of this 891 transaction can be removed from any checkpoint list it was on 892 before. */ 893 894 jbd_debug(3, "JBD2: commit phase 6\n"); 895 896 J_ASSERT(list_empty(&commit_transaction->t_inode_list)); 897 J_ASSERT(commit_transaction->t_buffers == NULL); 898 J_ASSERT(commit_transaction->t_checkpoint_list == NULL); 899 J_ASSERT(commit_transaction->t_shadow_list == NULL); 900 901 restart_loop: 902 /* 903 * As there are other places (journal_unmap_buffer()) adding buffers 904 * to this list we have to be careful and hold the j_list_lock. 905 */ 906 spin_lock(&journal->j_list_lock); 907 while (commit_transaction->t_forget) { 908 transaction_t *cp_transaction; 909 struct buffer_head *bh; 910 int try_to_free = 0; 911 912 jh = commit_transaction->t_forget; 913 spin_unlock(&journal->j_list_lock); 914 bh = jh2bh(jh); 915 /* 916 * Get a reference so that bh cannot be freed before we are 917 * done with it. 918 */ 919 get_bh(bh); 920 jbd_lock_bh_state(bh); 921 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction); 922 923 /* 924 * If there is undo-protected committed data against 925 * this buffer, then we can remove it now. If it is a 926 * buffer needing such protection, the old frozen_data 927 * field now points to a committed version of the 928 * buffer, so rotate that field to the new committed 929 * data. 930 * 931 * Otherwise, we can just throw away the frozen data now. 932 * 933 * We also know that the frozen data has already fired 934 * its triggers if they exist, so we can clear that too. 935 */ 936 if (jh->b_committed_data) { 937 jbd2_free(jh->b_committed_data, bh->b_size); 938 jh->b_committed_data = NULL; 939 if (jh->b_frozen_data) { 940 jh->b_committed_data = jh->b_frozen_data; 941 jh->b_frozen_data = NULL; 942 jh->b_frozen_triggers = NULL; 943 } 944 } else if (jh->b_frozen_data) { 945 jbd2_free(jh->b_frozen_data, bh->b_size); 946 jh->b_frozen_data = NULL; 947 jh->b_frozen_triggers = NULL; 948 } 949 950 spin_lock(&journal->j_list_lock); 951 cp_transaction = jh->b_cp_transaction; 952 if (cp_transaction) { 953 JBUFFER_TRACE(jh, "remove from old cp transaction"); 954 cp_transaction->t_chp_stats.cs_dropped++; 955 __jbd2_journal_remove_checkpoint(jh); 956 } 957 958 /* Only re-checkpoint the buffer_head if it is marked 959 * dirty. If the buffer was added to the BJ_Forget list 960 * by jbd2_journal_forget, it may no longer be dirty and 961 * there's no point in keeping a checkpoint record for 962 * it. */ 963 964 /* 965 * A buffer which has been freed while still being journaled by 966 * a previous transaction. 967 */ 968 if (buffer_freed(bh)) { 969 /* 970 * If the running transaction is the one containing 971 * "add to orphan" operation (b_next_transaction != 972 * NULL), we have to wait for that transaction to 973 * commit before we can really get rid of the buffer. 974 * So just clear b_modified to not confuse transaction 975 * credit accounting and refile the buffer to 976 * BJ_Forget of the running transaction. If the just 977 * committed transaction contains "add to orphan" 978 * operation, we can completely invalidate the buffer 979 * now. We are rather through in that since the 980 * buffer may be still accessible when blocksize < 981 * pagesize and it is attached to the last partial 982 * page. 983 */ 984 jh->b_modified = 0; 985 if (!jh->b_next_transaction) { 986 clear_buffer_freed(bh); 987 clear_buffer_jbddirty(bh); 988 clear_buffer_mapped(bh); 989 clear_buffer_new(bh); 990 clear_buffer_req(bh); 991 bh->b_bdev = NULL; 992 } 993 } 994 995 if (buffer_jbddirty(bh)) { 996 JBUFFER_TRACE(jh, "add to new checkpointing trans"); 997 __jbd2_journal_insert_checkpoint(jh, commit_transaction); 998 if (is_journal_aborted(journal)) 999 clear_buffer_jbddirty(bh); 1000 } else { 1001 J_ASSERT_BH(bh, !buffer_dirty(bh)); 1002 /* 1003 * The buffer on BJ_Forget list and not jbddirty means 1004 * it has been freed by this transaction and hence it 1005 * could not have been reallocated until this 1006 * transaction has committed. *BUT* it could be 1007 * reallocated once we have written all the data to 1008 * disk and before we process the buffer on BJ_Forget 1009 * list. 1010 */ 1011 if (!jh->b_next_transaction) 1012 try_to_free = 1; 1013 } 1014 JBUFFER_TRACE(jh, "refile or unfile buffer"); 1015 __jbd2_journal_refile_buffer(jh); 1016 jbd_unlock_bh_state(bh); 1017 if (try_to_free) 1018 release_buffer_page(bh); /* Drops bh reference */ 1019 else 1020 __brelse(bh); 1021 cond_resched_lock(&journal->j_list_lock); 1022 } 1023 spin_unlock(&journal->j_list_lock); 1024 /* 1025 * This is a bit sleazy. We use j_list_lock to protect transition 1026 * of a transaction into T_FINISHED state and calling 1027 * __jbd2_journal_drop_transaction(). Otherwise we could race with 1028 * other checkpointing code processing the transaction... 1029 */ 1030 write_lock(&journal->j_state_lock); 1031 spin_lock(&journal->j_list_lock); 1032 /* 1033 * Now recheck if some buffers did not get attached to the transaction 1034 * while the lock was dropped... 1035 */ 1036 if (commit_transaction->t_forget) { 1037 spin_unlock(&journal->j_list_lock); 1038 write_unlock(&journal->j_state_lock); 1039 goto restart_loop; 1040 } 1041 1042 /* Add the transaction to the checkpoint list 1043 * __journal_remove_checkpoint() can not destroy transaction 1044 * under us because it is not marked as T_FINISHED yet */ 1045 if (journal->j_checkpoint_transactions == NULL) { 1046 journal->j_checkpoint_transactions = commit_transaction; 1047 commit_transaction->t_cpnext = commit_transaction; 1048 commit_transaction->t_cpprev = commit_transaction; 1049 } else { 1050 commit_transaction->t_cpnext = 1051 journal->j_checkpoint_transactions; 1052 commit_transaction->t_cpprev = 1053 commit_transaction->t_cpnext->t_cpprev; 1054 commit_transaction->t_cpnext->t_cpprev = 1055 commit_transaction; 1056 commit_transaction->t_cpprev->t_cpnext = 1057 commit_transaction; 1058 } 1059 spin_unlock(&journal->j_list_lock); 1060 1061 /* Done with this transaction! */ 1062 1063 jbd_debug(3, "JBD2: commit phase 7\n"); 1064 1065 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH); 1066 1067 commit_transaction->t_start = jiffies; 1068 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging, 1069 commit_transaction->t_start); 1070 1071 /* 1072 * File the transaction statistics 1073 */ 1074 stats.ts_tid = commit_transaction->t_tid; 1075 stats.run.rs_handle_count = 1076 atomic_read(&commit_transaction->t_handle_count); 1077 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev, 1078 commit_transaction->t_tid, &stats.run); 1079 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0; 1080 1081 commit_transaction->t_state = T_COMMIT_CALLBACK; 1082 J_ASSERT(commit_transaction == journal->j_committing_transaction); 1083 journal->j_commit_sequence = commit_transaction->t_tid; 1084 journal->j_committing_transaction = NULL; 1085 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); 1086 1087 /* 1088 * weight the commit time higher than the average time so we don't 1089 * react too strongly to vast changes in the commit time 1090 */ 1091 if (likely(journal->j_average_commit_time)) 1092 journal->j_average_commit_time = (commit_time + 1093 journal->j_average_commit_time*3) / 4; 1094 else 1095 journal->j_average_commit_time = commit_time; 1096 1097 write_unlock(&journal->j_state_lock); 1098 1099 if (journal->j_commit_callback) 1100 journal->j_commit_callback(journal, commit_transaction); 1101 1102 trace_jbd2_end_commit(journal, commit_transaction); 1103 jbd_debug(1, "JBD2: commit %d complete, head %d\n", 1104 journal->j_commit_sequence, journal->j_tail_sequence); 1105 1106 write_lock(&journal->j_state_lock); 1107 spin_lock(&journal->j_list_lock); 1108 commit_transaction->t_state = T_FINISHED; 1109 /* Check if the transaction can be dropped now that we are finished */ 1110 if (commit_transaction->t_checkpoint_list == NULL && 1111 commit_transaction->t_checkpoint_io_list == NULL) { 1112 __jbd2_journal_drop_transaction(journal, commit_transaction); 1113 jbd2_journal_free_transaction(commit_transaction); 1114 } 1115 spin_unlock(&journal->j_list_lock); 1116 write_unlock(&journal->j_state_lock); 1117 wake_up(&journal->j_wait_done_commit); 1118 1119 /* 1120 * Calculate overall stats 1121 */ 1122 spin_lock(&journal->j_history_lock); 1123 journal->j_stats.ts_tid++; 1124 journal->j_stats.ts_requested += stats.ts_requested; 1125 journal->j_stats.run.rs_wait += stats.run.rs_wait; 1126 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay; 1127 journal->j_stats.run.rs_running += stats.run.rs_running; 1128 journal->j_stats.run.rs_locked += stats.run.rs_locked; 1129 journal->j_stats.run.rs_flushing += stats.run.rs_flushing; 1130 journal->j_stats.run.rs_logging += stats.run.rs_logging; 1131 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count; 1132 journal->j_stats.run.rs_blocks += stats.run.rs_blocks; 1133 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged; 1134 spin_unlock(&journal->j_history_lock); 1135 } 1136