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 page_cache_get(page); 85 __brelse(bh); 86 try_to_free_buffers(page); 87 unlock_page(page); 88 page_cache_release(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_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2)) 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(journal); 135 if (!bh) 136 return 1; 137 138 tmp = (struct commit_header *)bh->b_data; 139 tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); 140 tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK); 141 tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid); 142 tmp->h_commit_sec = cpu_to_be64(now.tv_sec); 143 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec); 144 145 if (JBD2_HAS_COMPAT_FEATURE(journal, 146 JBD2_FEATURE_COMPAT_CHECKSUM)) { 147 tmp->h_chksum_type = JBD2_CRC32_CHKSUM; 148 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE; 149 tmp->h_chksum[0] = cpu_to_be32(crc32_sum); 150 } 151 jbd2_commit_block_csum_set(journal, bh); 152 153 BUFFER_TRACE(bh, "submit commit block"); 154 lock_buffer(bh); 155 clear_buffer_dirty(bh); 156 set_buffer_uptodate(bh); 157 bh->b_end_io = journal_end_buffer_io_sync; 158 159 if (journal->j_flags & JBD2_BARRIER && 160 !JBD2_HAS_INCOMPAT_FEATURE(journal, 161 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) 162 ret = submit_bh(WRITE_SYNC | WRITE_FLUSH_FUA, bh); 163 else 164 ret = submit_bh(WRITE_SYNC, bh); 165 166 *cbh = bh; 167 return ret; 168 } 169 170 /* 171 * This function along with journal_submit_commit_record 172 * allows to write the commit record asynchronously. 173 */ 174 static int journal_wait_on_commit_record(journal_t *journal, 175 struct buffer_head *bh) 176 { 177 int ret = 0; 178 179 clear_buffer_dirty(bh); 180 wait_on_buffer(bh); 181 182 if (unlikely(!buffer_uptodate(bh))) 183 ret = -EIO; 184 put_bh(bh); /* One for getblk() */ 185 186 return ret; 187 } 188 189 /* 190 * write the filemap data using writepage() address_space_operations. 191 * We don't do block allocation here even for delalloc. We don't 192 * use writepages() because with dealyed allocation we may be doing 193 * block allocation in writepages(). 194 */ 195 static int journal_submit_inode_data_buffers(struct address_space *mapping) 196 { 197 int ret; 198 struct writeback_control wbc = { 199 .sync_mode = WB_SYNC_ALL, 200 .nr_to_write = mapping->nrpages * 2, 201 .range_start = 0, 202 .range_end = i_size_read(mapping->host), 203 }; 204 205 ret = generic_writepages(mapping, &wbc); 206 return ret; 207 } 208 209 /* 210 * Submit all the data buffers of inode associated with the transaction to 211 * disk. 212 * 213 * We are in a committing transaction. Therefore no new inode can be added to 214 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently 215 * operate on from being released while we write out pages. 216 */ 217 static int journal_submit_data_buffers(journal_t *journal, 218 transaction_t *commit_transaction) 219 { 220 struct jbd2_inode *jinode; 221 int err, ret = 0; 222 struct address_space *mapping; 223 224 spin_lock(&journal->j_list_lock); 225 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 226 mapping = jinode->i_vfs_inode->i_mapping; 227 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 228 spin_unlock(&journal->j_list_lock); 229 /* 230 * submit the inode data buffers. We use writepage 231 * instead of writepages. Because writepages can do 232 * block allocation with delalloc. We need to write 233 * only allocated blocks here. 234 */ 235 trace_jbd2_submit_inode_data(jinode->i_vfs_inode); 236 err = journal_submit_inode_data_buffers(mapping); 237 if (!ret) 238 ret = err; 239 spin_lock(&journal->j_list_lock); 240 J_ASSERT(jinode->i_transaction == commit_transaction); 241 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 242 smp_mb__after_atomic(); 243 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 244 } 245 spin_unlock(&journal->j_list_lock); 246 return ret; 247 } 248 249 /* 250 * Wait for data submitted for writeout, refile inodes to proper 251 * transaction if needed. 252 * 253 */ 254 static int journal_finish_inode_data_buffers(journal_t *journal, 255 transaction_t *commit_transaction) 256 { 257 struct jbd2_inode *jinode, *next_i; 258 int err, ret = 0; 259 260 /* For locking, see the comment in journal_submit_data_buffers() */ 261 spin_lock(&journal->j_list_lock); 262 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { 263 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 264 spin_unlock(&journal->j_list_lock); 265 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping); 266 if (err) { 267 /* 268 * Because AS_EIO is cleared by 269 * filemap_fdatawait_range(), set it again so 270 * that user process can get -EIO from fsync(). 271 */ 272 set_bit(AS_EIO, 273 &jinode->i_vfs_inode->i_mapping->flags); 274 275 if (!ret) 276 ret = err; 277 } 278 spin_lock(&journal->j_list_lock); 279 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags); 280 smp_mb__after_atomic(); 281 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); 282 } 283 284 /* Now refile inode to proper lists */ 285 list_for_each_entry_safe(jinode, next_i, 286 &commit_transaction->t_inode_list, i_list) { 287 list_del(&jinode->i_list); 288 if (jinode->i_next_transaction) { 289 jinode->i_transaction = jinode->i_next_transaction; 290 jinode->i_next_transaction = NULL; 291 list_add(&jinode->i_list, 292 &jinode->i_transaction->t_inode_list); 293 } else { 294 jinode->i_transaction = NULL; 295 } 296 } 297 spin_unlock(&journal->j_list_lock); 298 299 return ret; 300 } 301 302 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh) 303 { 304 struct page *page = bh->b_page; 305 char *addr; 306 __u32 checksum; 307 308 addr = kmap_atomic(page); 309 checksum = crc32_be(crc32_sum, 310 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size); 311 kunmap_atomic(addr); 312 313 return checksum; 314 } 315 316 static void write_tag_block(int tag_bytes, journal_block_tag_t *tag, 317 unsigned long long block) 318 { 319 tag->t_blocknr = cpu_to_be32(block & (u32)~0); 320 if (tag_bytes > JBD2_TAG_SIZE32) 321 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1); 322 } 323 324 static void jbd2_descr_block_csum_set(journal_t *j, 325 struct buffer_head *bh) 326 { 327 struct jbd2_journal_block_tail *tail; 328 __u32 csum; 329 330 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2)) 331 return; 332 333 tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize - 334 sizeof(struct jbd2_journal_block_tail)); 335 tail->t_checksum = 0; 336 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize); 337 tail->t_checksum = cpu_to_be32(csum); 338 } 339 340 static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag, 341 struct buffer_head *bh, __u32 sequence) 342 { 343 struct page *page = bh->b_page; 344 __u8 *addr; 345 __u32 csum32; 346 __be32 seq; 347 348 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2)) 349 return; 350 351 seq = cpu_to_be32(sequence); 352 addr = kmap_atomic(page); 353 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq)); 354 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data), 355 bh->b_size); 356 kunmap_atomic(addr); 357 358 /* We only have space to store the lower 16 bits of the crc32c. */ 359 tag->t_checksum = cpu_to_be16(csum32); 360 } 361 /* 362 * jbd2_journal_commit_transaction 363 * 364 * The primary function for committing a transaction to the log. This 365 * function is called by the journal thread to begin a complete commit. 366 */ 367 void jbd2_journal_commit_transaction(journal_t *journal) 368 { 369 struct transaction_stats_s stats; 370 transaction_t *commit_transaction; 371 struct journal_head *jh; 372 struct buffer_head *descriptor; 373 struct buffer_head **wbuf = journal->j_wbuf; 374 int bufs; 375 int flags; 376 int err; 377 unsigned long long blocknr; 378 ktime_t start_time; 379 u64 commit_time; 380 char *tagp = NULL; 381 journal_header_t *header; 382 journal_block_tag_t *tag = NULL; 383 int space_left = 0; 384 int first_tag = 0; 385 int tag_flag; 386 int i; 387 int tag_bytes = journal_tag_bytes(journal); 388 struct buffer_head *cbh = NULL; /* For transactional checksums */ 389 __u32 crc32_sum = ~0; 390 struct blk_plug plug; 391 /* Tail of the journal */ 392 unsigned long first_block; 393 tid_t first_tid; 394 int update_tail; 395 int csum_size = 0; 396 LIST_HEAD(io_bufs); 397 LIST_HEAD(log_bufs); 398 399 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2)) 400 csum_size = sizeof(struct jbd2_journal_block_tail); 401 402 /* 403 * First job: lock down the current transaction and wait for 404 * all outstanding updates to complete. 405 */ 406 407 /* Do we need to erase the effects of a prior jbd2_journal_flush? */ 408 if (journal->j_flags & JBD2_FLUSHED) { 409 jbd_debug(3, "super block updated\n"); 410 mutex_lock(&journal->j_checkpoint_mutex); 411 /* 412 * We hold j_checkpoint_mutex so tail cannot change under us. 413 * We don't need any special data guarantees for writing sb 414 * since journal is empty and it is ok for write to be 415 * flushed only with transaction commit. 416 */ 417 jbd2_journal_update_sb_log_tail(journal, 418 journal->j_tail_sequence, 419 journal->j_tail, 420 WRITE_SYNC); 421 mutex_unlock(&journal->j_checkpoint_mutex); 422 } else { 423 jbd_debug(3, "superblock not updated\n"); 424 } 425 426 J_ASSERT(journal->j_running_transaction != NULL); 427 J_ASSERT(journal->j_committing_transaction == NULL); 428 429 commit_transaction = journal->j_running_transaction; 430 431 trace_jbd2_start_commit(journal, commit_transaction); 432 jbd_debug(1, "JBD2: starting commit of transaction %d\n", 433 commit_transaction->t_tid); 434 435 write_lock(&journal->j_state_lock); 436 J_ASSERT(commit_transaction->t_state == T_RUNNING); 437 commit_transaction->t_state = T_LOCKED; 438 439 trace_jbd2_commit_locking(journal, commit_transaction); 440 stats.run.rs_wait = commit_transaction->t_max_wait; 441 stats.run.rs_request_delay = 0; 442 stats.run.rs_locked = jiffies; 443 if (commit_transaction->t_requested) 444 stats.run.rs_request_delay = 445 jbd2_time_diff(commit_transaction->t_requested, 446 stats.run.rs_locked); 447 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start, 448 stats.run.rs_locked); 449 450 spin_lock(&commit_transaction->t_handle_lock); 451 while (atomic_read(&commit_transaction->t_updates)) { 452 DEFINE_WAIT(wait); 453 454 prepare_to_wait(&journal->j_wait_updates, &wait, 455 TASK_UNINTERRUPTIBLE); 456 if (atomic_read(&commit_transaction->t_updates)) { 457 spin_unlock(&commit_transaction->t_handle_lock); 458 write_unlock(&journal->j_state_lock); 459 schedule(); 460 write_lock(&journal->j_state_lock); 461 spin_lock(&commit_transaction->t_handle_lock); 462 } 463 finish_wait(&journal->j_wait_updates, &wait); 464 } 465 spin_unlock(&commit_transaction->t_handle_lock); 466 467 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <= 468 journal->j_max_transaction_buffers); 469 470 /* 471 * First thing we are allowed to do is to discard any remaining 472 * BJ_Reserved buffers. Note, it is _not_ permissible to assume 473 * that there are no such buffers: if a large filesystem 474 * operation like a truncate needs to split itself over multiple 475 * transactions, then it may try to do a jbd2_journal_restart() while 476 * there are still BJ_Reserved buffers outstanding. These must 477 * be released cleanly from the current transaction. 478 * 479 * In this case, the filesystem must still reserve write access 480 * again before modifying the buffer in the new transaction, but 481 * we do not require it to remember exactly which old buffers it 482 * has reserved. This is consistent with the existing behaviour 483 * that multiple jbd2_journal_get_write_access() calls to the same 484 * buffer are perfectly permissible. 485 */ 486 while (commit_transaction->t_reserved_list) { 487 jh = commit_transaction->t_reserved_list; 488 JBUFFER_TRACE(jh, "reserved, unused: refile"); 489 /* 490 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may 491 * leave undo-committed data. 492 */ 493 if (jh->b_committed_data) { 494 struct buffer_head *bh = jh2bh(jh); 495 496 jbd_lock_bh_state(bh); 497 jbd2_free(jh->b_committed_data, bh->b_size); 498 jh->b_committed_data = NULL; 499 jbd_unlock_bh_state(bh); 500 } 501 jbd2_journal_refile_buffer(journal, jh); 502 } 503 504 /* 505 * Now try to drop any written-back buffers from the journal's 506 * checkpoint lists. We do this *before* commit because it potentially 507 * frees some memory 508 */ 509 spin_lock(&journal->j_list_lock); 510 __jbd2_journal_clean_checkpoint_list(journal); 511 spin_unlock(&journal->j_list_lock); 512 513 jbd_debug(3, "JBD2: commit phase 1\n"); 514 515 /* 516 * Clear revoked flag to reflect there is no revoked buffers 517 * in the next transaction which is going to be started. 518 */ 519 jbd2_clear_buffer_revoked_flags(journal); 520 521 /* 522 * Switch to a new revoke table. 523 */ 524 jbd2_journal_switch_revoke_table(journal); 525 526 /* 527 * Reserved credits cannot be claimed anymore, free them 528 */ 529 atomic_sub(atomic_read(&journal->j_reserved_credits), 530 &commit_transaction->t_outstanding_credits); 531 532 trace_jbd2_commit_flushing(journal, commit_transaction); 533 stats.run.rs_flushing = jiffies; 534 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked, 535 stats.run.rs_flushing); 536 537 commit_transaction->t_state = T_FLUSH; 538 journal->j_committing_transaction = commit_transaction; 539 journal->j_running_transaction = NULL; 540 start_time = ktime_get(); 541 commit_transaction->t_log_start = journal->j_head; 542 wake_up(&journal->j_wait_transaction_locked); 543 write_unlock(&journal->j_state_lock); 544 545 jbd_debug(3, "JBD2: commit phase 2a\n"); 546 547 /* 548 * Now start flushing things to disk, in the order they appear 549 * on the transaction lists. Data blocks go first. 550 */ 551 err = journal_submit_data_buffers(journal, commit_transaction); 552 if (err) 553 jbd2_journal_abort(journal, err); 554 555 blk_start_plug(&plug); 556 jbd2_journal_write_revoke_records(journal, commit_transaction, 557 &log_bufs, WRITE_SYNC); 558 559 jbd_debug(3, "JBD2: commit phase 2b\n"); 560 561 /* 562 * Way to go: we have now written out all of the data for a 563 * transaction! Now comes the tricky part: we need to write out 564 * metadata. Loop over the transaction's entire buffer list: 565 */ 566 write_lock(&journal->j_state_lock); 567 commit_transaction->t_state = T_COMMIT; 568 write_unlock(&journal->j_state_lock); 569 570 trace_jbd2_commit_logging(journal, commit_transaction); 571 stats.run.rs_logging = jiffies; 572 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing, 573 stats.run.rs_logging); 574 stats.run.rs_blocks = 575 atomic_read(&commit_transaction->t_outstanding_credits); 576 stats.run.rs_blocks_logged = 0; 577 578 J_ASSERT(commit_transaction->t_nr_buffers <= 579 atomic_read(&commit_transaction->t_outstanding_credits)); 580 581 err = 0; 582 bufs = 0; 583 descriptor = NULL; 584 while (commit_transaction->t_buffers) { 585 586 /* Find the next buffer to be journaled... */ 587 588 jh = commit_transaction->t_buffers; 589 590 /* If we're in abort mode, we just un-journal the buffer and 591 release it. */ 592 593 if (is_journal_aborted(journal)) { 594 clear_buffer_jbddirty(jh2bh(jh)); 595 JBUFFER_TRACE(jh, "journal is aborting: refile"); 596 jbd2_buffer_abort_trigger(jh, 597 jh->b_frozen_data ? 598 jh->b_frozen_triggers : 599 jh->b_triggers); 600 jbd2_journal_refile_buffer(journal, jh); 601 /* If that was the last one, we need to clean up 602 * any descriptor buffers which may have been 603 * already allocated, even if we are now 604 * aborting. */ 605 if (!commit_transaction->t_buffers) 606 goto start_journal_io; 607 continue; 608 } 609 610 /* Make sure we have a descriptor block in which to 611 record the metadata buffer. */ 612 613 if (!descriptor) { 614 J_ASSERT (bufs == 0); 615 616 jbd_debug(4, "JBD2: get descriptor\n"); 617 618 descriptor = jbd2_journal_get_descriptor_buffer(journal); 619 if (!descriptor) { 620 jbd2_journal_abort(journal, -EIO); 621 continue; 622 } 623 624 jbd_debug(4, "JBD2: got buffer %llu (%p)\n", 625 (unsigned long long)descriptor->b_blocknr, 626 descriptor->b_data); 627 header = (journal_header_t *)descriptor->b_data; 628 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); 629 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK); 630 header->h_sequence = cpu_to_be32(commit_transaction->t_tid); 631 632 tagp = &descriptor->b_data[sizeof(journal_header_t)]; 633 space_left = descriptor->b_size - 634 sizeof(journal_header_t); 635 first_tag = 1; 636 set_buffer_jwrite(descriptor); 637 set_buffer_dirty(descriptor); 638 wbuf[bufs++] = descriptor; 639 640 /* Record it so that we can wait for IO 641 completion later */ 642 BUFFER_TRACE(descriptor, "ph3: file as descriptor"); 643 jbd2_file_log_bh(&log_bufs, descriptor); 644 } 645 646 /* Where is the buffer to be written? */ 647 648 err = jbd2_journal_next_log_block(journal, &blocknr); 649 /* If the block mapping failed, just abandon the buffer 650 and repeat this loop: we'll fall into the 651 refile-on-abort condition above. */ 652 if (err) { 653 jbd2_journal_abort(journal, err); 654 continue; 655 } 656 657 /* 658 * start_this_handle() uses t_outstanding_credits to determine 659 * the free space in the log, but this counter is changed 660 * by jbd2_journal_next_log_block() also. 661 */ 662 atomic_dec(&commit_transaction->t_outstanding_credits); 663 664 /* Bump b_count to prevent truncate from stumbling over 665 the shadowed buffer! @@@ This can go if we ever get 666 rid of the shadow pairing of buffers. */ 667 atomic_inc(&jh2bh(jh)->b_count); 668 669 /* 670 * Make a temporary IO buffer with which to write it out 671 * (this will requeue the metadata buffer to BJ_Shadow). 672 */ 673 set_bit(BH_JWrite, &jh2bh(jh)->b_state); 674 JBUFFER_TRACE(jh, "ph3: write metadata"); 675 flags = jbd2_journal_write_metadata_buffer(commit_transaction, 676 jh, &wbuf[bufs], blocknr); 677 if (flags < 0) { 678 jbd2_journal_abort(journal, flags); 679 continue; 680 } 681 jbd2_file_log_bh(&io_bufs, wbuf[bufs]); 682 683 /* Record the new block's tag in the current descriptor 684 buffer */ 685 686 tag_flag = 0; 687 if (flags & 1) 688 tag_flag |= JBD2_FLAG_ESCAPE; 689 if (!first_tag) 690 tag_flag |= JBD2_FLAG_SAME_UUID; 691 692 tag = (journal_block_tag_t *) tagp; 693 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr); 694 tag->t_flags = cpu_to_be16(tag_flag); 695 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs], 696 commit_transaction->t_tid); 697 tagp += tag_bytes; 698 space_left -= tag_bytes; 699 bufs++; 700 701 if (first_tag) { 702 memcpy (tagp, journal->j_uuid, 16); 703 tagp += 16; 704 space_left -= 16; 705 first_tag = 0; 706 } 707 708 /* If there's no more to do, or if the descriptor is full, 709 let the IO rip! */ 710 711 if (bufs == journal->j_wbufsize || 712 commit_transaction->t_buffers == NULL || 713 space_left < tag_bytes + 16 + csum_size) { 714 715 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs); 716 717 /* Write an end-of-descriptor marker before 718 submitting the IOs. "tag" still points to 719 the last tag we set up. */ 720 721 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG); 722 723 jbd2_descr_block_csum_set(journal, descriptor); 724 start_journal_io: 725 for (i = 0; i < bufs; i++) { 726 struct buffer_head *bh = wbuf[i]; 727 /* 728 * Compute checksum. 729 */ 730 if (JBD2_HAS_COMPAT_FEATURE(journal, 731 JBD2_FEATURE_COMPAT_CHECKSUM)) { 732 crc32_sum = 733 jbd2_checksum_data(crc32_sum, bh); 734 } 735 736 lock_buffer(bh); 737 clear_buffer_dirty(bh); 738 set_buffer_uptodate(bh); 739 bh->b_end_io = journal_end_buffer_io_sync; 740 submit_bh(WRITE_SYNC, bh); 741 } 742 cond_resched(); 743 stats.run.rs_blocks_logged += bufs; 744 745 /* Force a new descriptor to be generated next 746 time round the loop. */ 747 descriptor = NULL; 748 bufs = 0; 749 } 750 } 751 752 err = journal_finish_inode_data_buffers(journal, commit_transaction); 753 if (err) { 754 printk(KERN_WARNING 755 "JBD2: Detected IO errors while flushing file data " 756 "on %s\n", journal->j_devname); 757 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR) 758 jbd2_journal_abort(journal, err); 759 err = 0; 760 } 761 762 /* 763 * Get current oldest transaction in the log before we issue flush 764 * to the filesystem device. After the flush we can be sure that 765 * blocks of all older transactions are checkpointed to persistent 766 * storage and we will be safe to update journal start in the 767 * superblock with the numbers we get here. 768 */ 769 update_tail = 770 jbd2_journal_get_log_tail(journal, &first_tid, &first_block); 771 772 write_lock(&journal->j_state_lock); 773 if (update_tail) { 774 long freed = first_block - journal->j_tail; 775 776 if (first_block < journal->j_tail) 777 freed += journal->j_last - journal->j_first; 778 /* Update tail only if we free significant amount of space */ 779 if (freed < journal->j_maxlen / 4) 780 update_tail = 0; 781 } 782 J_ASSERT(commit_transaction->t_state == T_COMMIT); 783 commit_transaction->t_state = T_COMMIT_DFLUSH; 784 write_unlock(&journal->j_state_lock); 785 786 /* 787 * If the journal is not located on the file system device, 788 * then we must flush the file system device before we issue 789 * the commit record 790 */ 791 if (commit_transaction->t_need_data_flush && 792 (journal->j_fs_dev != journal->j_dev) && 793 (journal->j_flags & JBD2_BARRIER)) 794 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL); 795 796 /* Done it all: now write the commit record asynchronously. */ 797 if (JBD2_HAS_INCOMPAT_FEATURE(journal, 798 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 799 err = journal_submit_commit_record(journal, commit_transaction, 800 &cbh, crc32_sum); 801 if (err) 802 __jbd2_journal_abort_hard(journal); 803 } 804 805 blk_finish_plug(&plug); 806 807 /* Lo and behold: we have just managed to send a transaction to 808 the log. Before we can commit it, wait for the IO so far to 809 complete. Control buffers being written are on the 810 transaction's t_log_list queue, and metadata buffers are on 811 the io_bufs list. 812 813 Wait for the buffers in reverse order. That way we are 814 less likely to be woken up until all IOs have completed, and 815 so we incur less scheduling load. 816 */ 817 818 jbd_debug(3, "JBD2: commit phase 3\n"); 819 820 while (!list_empty(&io_bufs)) { 821 struct buffer_head *bh = list_entry(io_bufs.prev, 822 struct buffer_head, 823 b_assoc_buffers); 824 825 wait_on_buffer(bh); 826 cond_resched(); 827 828 if (unlikely(!buffer_uptodate(bh))) 829 err = -EIO; 830 jbd2_unfile_log_bh(bh); 831 832 /* 833 * The list contains temporary buffer heads created by 834 * jbd2_journal_write_metadata_buffer(). 835 */ 836 BUFFER_TRACE(bh, "dumping temporary bh"); 837 __brelse(bh); 838 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0); 839 free_buffer_head(bh); 840 841 /* We also have to refile the corresponding shadowed buffer */ 842 jh = commit_transaction->t_shadow_list->b_tprev; 843 bh = jh2bh(jh); 844 clear_buffer_jwrite(bh); 845 J_ASSERT_BH(bh, buffer_jbddirty(bh)); 846 J_ASSERT_BH(bh, !buffer_shadow(bh)); 847 848 /* The metadata is now released for reuse, but we need 849 to remember it against this transaction so that when 850 we finally commit, we can do any checkpointing 851 required. */ 852 JBUFFER_TRACE(jh, "file as BJ_Forget"); 853 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget); 854 JBUFFER_TRACE(jh, "brelse shadowed buffer"); 855 __brelse(bh); 856 } 857 858 J_ASSERT (commit_transaction->t_shadow_list == NULL); 859 860 jbd_debug(3, "JBD2: commit phase 4\n"); 861 862 /* Here we wait for the revoke record and descriptor record buffers */ 863 while (!list_empty(&log_bufs)) { 864 struct buffer_head *bh; 865 866 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers); 867 wait_on_buffer(bh); 868 cond_resched(); 869 870 if (unlikely(!buffer_uptodate(bh))) 871 err = -EIO; 872 873 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile"); 874 clear_buffer_jwrite(bh); 875 jbd2_unfile_log_bh(bh); 876 __brelse(bh); /* One for getblk */ 877 /* AKPM: bforget here */ 878 } 879 880 if (err) 881 jbd2_journal_abort(journal, err); 882 883 jbd_debug(3, "JBD2: commit phase 5\n"); 884 write_lock(&journal->j_state_lock); 885 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH); 886 commit_transaction->t_state = T_COMMIT_JFLUSH; 887 write_unlock(&journal->j_state_lock); 888 889 if (!JBD2_HAS_INCOMPAT_FEATURE(journal, 890 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 891 err = journal_submit_commit_record(journal, commit_transaction, 892 &cbh, crc32_sum); 893 if (err) 894 __jbd2_journal_abort_hard(journal); 895 } 896 if (cbh) 897 err = journal_wait_on_commit_record(journal, cbh); 898 if (JBD2_HAS_INCOMPAT_FEATURE(journal, 899 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) && 900 journal->j_flags & JBD2_BARRIER) { 901 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL); 902 } 903 904 if (err) 905 jbd2_journal_abort(journal, err); 906 907 /* 908 * Now disk caches for filesystem device are flushed so we are safe to 909 * erase checkpointed transactions from the log by updating journal 910 * superblock. 911 */ 912 if (update_tail) 913 jbd2_update_log_tail(journal, first_tid, first_block); 914 915 /* End of a transaction! Finally, we can do checkpoint 916 processing: any buffers committed as a result of this 917 transaction can be removed from any checkpoint list it was on 918 before. */ 919 920 jbd_debug(3, "JBD2: commit phase 6\n"); 921 922 J_ASSERT(list_empty(&commit_transaction->t_inode_list)); 923 J_ASSERT(commit_transaction->t_buffers == NULL); 924 J_ASSERT(commit_transaction->t_checkpoint_list == NULL); 925 J_ASSERT(commit_transaction->t_shadow_list == NULL); 926 927 restart_loop: 928 /* 929 * As there are other places (journal_unmap_buffer()) adding buffers 930 * to this list we have to be careful and hold the j_list_lock. 931 */ 932 spin_lock(&journal->j_list_lock); 933 while (commit_transaction->t_forget) { 934 transaction_t *cp_transaction; 935 struct buffer_head *bh; 936 int try_to_free = 0; 937 938 jh = commit_transaction->t_forget; 939 spin_unlock(&journal->j_list_lock); 940 bh = jh2bh(jh); 941 /* 942 * Get a reference so that bh cannot be freed before we are 943 * done with it. 944 */ 945 get_bh(bh); 946 jbd_lock_bh_state(bh); 947 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction); 948 949 /* 950 * If there is undo-protected committed data against 951 * this buffer, then we can remove it now. If it is a 952 * buffer needing such protection, the old frozen_data 953 * field now points to a committed version of the 954 * buffer, so rotate that field to the new committed 955 * data. 956 * 957 * Otherwise, we can just throw away the frozen data now. 958 * 959 * We also know that the frozen data has already fired 960 * its triggers if they exist, so we can clear that too. 961 */ 962 if (jh->b_committed_data) { 963 jbd2_free(jh->b_committed_data, bh->b_size); 964 jh->b_committed_data = NULL; 965 if (jh->b_frozen_data) { 966 jh->b_committed_data = jh->b_frozen_data; 967 jh->b_frozen_data = NULL; 968 jh->b_frozen_triggers = NULL; 969 } 970 } else if (jh->b_frozen_data) { 971 jbd2_free(jh->b_frozen_data, bh->b_size); 972 jh->b_frozen_data = NULL; 973 jh->b_frozen_triggers = NULL; 974 } 975 976 spin_lock(&journal->j_list_lock); 977 cp_transaction = jh->b_cp_transaction; 978 if (cp_transaction) { 979 JBUFFER_TRACE(jh, "remove from old cp transaction"); 980 cp_transaction->t_chp_stats.cs_dropped++; 981 __jbd2_journal_remove_checkpoint(jh); 982 } 983 984 /* Only re-checkpoint the buffer_head if it is marked 985 * dirty. If the buffer was added to the BJ_Forget list 986 * by jbd2_journal_forget, it may no longer be dirty and 987 * there's no point in keeping a checkpoint record for 988 * it. */ 989 990 /* 991 * A buffer which has been freed while still being journaled by 992 * a previous transaction. 993 */ 994 if (buffer_freed(bh)) { 995 /* 996 * If the running transaction is the one containing 997 * "add to orphan" operation (b_next_transaction != 998 * NULL), we have to wait for that transaction to 999 * commit before we can really get rid of the buffer. 1000 * So just clear b_modified to not confuse transaction 1001 * credit accounting and refile the buffer to 1002 * BJ_Forget of the running transaction. If the just 1003 * committed transaction contains "add to orphan" 1004 * operation, we can completely invalidate the buffer 1005 * now. We are rather through in that since the 1006 * buffer may be still accessible when blocksize < 1007 * pagesize and it is attached to the last partial 1008 * page. 1009 */ 1010 jh->b_modified = 0; 1011 if (!jh->b_next_transaction) { 1012 clear_buffer_freed(bh); 1013 clear_buffer_jbddirty(bh); 1014 clear_buffer_mapped(bh); 1015 clear_buffer_new(bh); 1016 clear_buffer_req(bh); 1017 bh->b_bdev = NULL; 1018 } 1019 } 1020 1021 if (buffer_jbddirty(bh)) { 1022 JBUFFER_TRACE(jh, "add to new checkpointing trans"); 1023 __jbd2_journal_insert_checkpoint(jh, commit_transaction); 1024 if (is_journal_aborted(journal)) 1025 clear_buffer_jbddirty(bh); 1026 } else { 1027 J_ASSERT_BH(bh, !buffer_dirty(bh)); 1028 /* 1029 * The buffer on BJ_Forget list and not jbddirty means 1030 * it has been freed by this transaction and hence it 1031 * could not have been reallocated until this 1032 * transaction has committed. *BUT* it could be 1033 * reallocated once we have written all the data to 1034 * disk and before we process the buffer on BJ_Forget 1035 * list. 1036 */ 1037 if (!jh->b_next_transaction) 1038 try_to_free = 1; 1039 } 1040 JBUFFER_TRACE(jh, "refile or unfile buffer"); 1041 __jbd2_journal_refile_buffer(jh); 1042 jbd_unlock_bh_state(bh); 1043 if (try_to_free) 1044 release_buffer_page(bh); /* Drops bh reference */ 1045 else 1046 __brelse(bh); 1047 cond_resched_lock(&journal->j_list_lock); 1048 } 1049 spin_unlock(&journal->j_list_lock); 1050 /* 1051 * This is a bit sleazy. We use j_list_lock to protect transition 1052 * of a transaction into T_FINISHED state and calling 1053 * __jbd2_journal_drop_transaction(). Otherwise we could race with 1054 * other checkpointing code processing the transaction... 1055 */ 1056 write_lock(&journal->j_state_lock); 1057 spin_lock(&journal->j_list_lock); 1058 /* 1059 * Now recheck if some buffers did not get attached to the transaction 1060 * while the lock was dropped... 1061 */ 1062 if (commit_transaction->t_forget) { 1063 spin_unlock(&journal->j_list_lock); 1064 write_unlock(&journal->j_state_lock); 1065 goto restart_loop; 1066 } 1067 1068 /* Add the transaction to the checkpoint list 1069 * __journal_remove_checkpoint() can not destroy transaction 1070 * under us because it is not marked as T_FINISHED yet */ 1071 if (journal->j_checkpoint_transactions == NULL) { 1072 journal->j_checkpoint_transactions = commit_transaction; 1073 commit_transaction->t_cpnext = commit_transaction; 1074 commit_transaction->t_cpprev = commit_transaction; 1075 } else { 1076 commit_transaction->t_cpnext = 1077 journal->j_checkpoint_transactions; 1078 commit_transaction->t_cpprev = 1079 commit_transaction->t_cpnext->t_cpprev; 1080 commit_transaction->t_cpnext->t_cpprev = 1081 commit_transaction; 1082 commit_transaction->t_cpprev->t_cpnext = 1083 commit_transaction; 1084 } 1085 spin_unlock(&journal->j_list_lock); 1086 1087 /* Done with this transaction! */ 1088 1089 jbd_debug(3, "JBD2: commit phase 7\n"); 1090 1091 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH); 1092 1093 commit_transaction->t_start = jiffies; 1094 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging, 1095 commit_transaction->t_start); 1096 1097 /* 1098 * File the transaction statistics 1099 */ 1100 stats.ts_tid = commit_transaction->t_tid; 1101 stats.run.rs_handle_count = 1102 atomic_read(&commit_transaction->t_handle_count); 1103 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev, 1104 commit_transaction->t_tid, &stats.run); 1105 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0; 1106 1107 commit_transaction->t_state = T_COMMIT_CALLBACK; 1108 J_ASSERT(commit_transaction == journal->j_committing_transaction); 1109 journal->j_commit_sequence = commit_transaction->t_tid; 1110 journal->j_committing_transaction = NULL; 1111 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time)); 1112 1113 /* 1114 * weight the commit time higher than the average time so we don't 1115 * react too strongly to vast changes in the commit time 1116 */ 1117 if (likely(journal->j_average_commit_time)) 1118 journal->j_average_commit_time = (commit_time + 1119 journal->j_average_commit_time*3) / 4; 1120 else 1121 journal->j_average_commit_time = commit_time; 1122 1123 write_unlock(&journal->j_state_lock); 1124 1125 if (journal->j_commit_callback) 1126 journal->j_commit_callback(journal, commit_transaction); 1127 1128 trace_jbd2_end_commit(journal, commit_transaction); 1129 jbd_debug(1, "JBD2: commit %d complete, head %d\n", 1130 journal->j_commit_sequence, journal->j_tail_sequence); 1131 1132 write_lock(&journal->j_state_lock); 1133 spin_lock(&journal->j_list_lock); 1134 commit_transaction->t_state = T_FINISHED; 1135 /* Check if the transaction can be dropped now that we are finished */ 1136 if (commit_transaction->t_checkpoint_list == NULL && 1137 commit_transaction->t_checkpoint_io_list == NULL) { 1138 __jbd2_journal_drop_transaction(journal, commit_transaction); 1139 jbd2_journal_free_transaction(commit_transaction); 1140 } 1141 spin_unlock(&journal->j_list_lock); 1142 write_unlock(&journal->j_state_lock); 1143 wake_up(&journal->j_wait_done_commit); 1144 1145 /* 1146 * Calculate overall stats 1147 */ 1148 spin_lock(&journal->j_history_lock); 1149 journal->j_stats.ts_tid++; 1150 journal->j_stats.ts_requested += stats.ts_requested; 1151 journal->j_stats.run.rs_wait += stats.run.rs_wait; 1152 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay; 1153 journal->j_stats.run.rs_running += stats.run.rs_running; 1154 journal->j_stats.run.rs_locked += stats.run.rs_locked; 1155 journal->j_stats.run.rs_flushing += stats.run.rs_flushing; 1156 journal->j_stats.run.rs_logging += stats.run.rs_logging; 1157 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count; 1158 journal->j_stats.run.rs_blocks += stats.run.rs_blocks; 1159 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged; 1160 spin_unlock(&journal->j_history_lock); 1161 } 1162