1 /* 2 * linux/fs/jbd2/journal.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 * Generic filesystem journal-writing code; part of the ext2fs 13 * journaling system. 14 * 15 * This file manages journals: areas of disk reserved for logging 16 * transactional updates. This includes the kernel journaling thread 17 * which is responsible for scheduling updates to the log. 18 * 19 * We do not actually manage the physical storage of the journal in this 20 * file: that is left to a per-journal policy function, which allows us 21 * to store the journal within a filesystem-specified area for ext2 22 * journaling (ext2 can use a reserved inode for storing the log). 23 */ 24 25 #include <linux/module.h> 26 #include <linux/time.h> 27 #include <linux/fs.h> 28 #include <linux/jbd2.h> 29 #include <linux/errno.h> 30 #include <linux/slab.h> 31 #include <linux/init.h> 32 #include <linux/mm.h> 33 #include <linux/freezer.h> 34 #include <linux/pagemap.h> 35 #include <linux/kthread.h> 36 #include <linux/poison.h> 37 #include <linux/proc_fs.h> 38 #include <linux/debugfs.h> 39 #include <linux/seq_file.h> 40 #include <linux/math64.h> 41 #include <linux/hash.h> 42 #include <linux/log2.h> 43 #include <linux/vmalloc.h> 44 #include <linux/backing-dev.h> 45 #include <linux/bitops.h> 46 #include <linux/ratelimit.h> 47 48 #define CREATE_TRACE_POINTS 49 #include <trace/events/jbd2.h> 50 51 #include <asm/uaccess.h> 52 #include <asm/page.h> 53 #include <asm/system.h> 54 55 EXPORT_SYMBOL(jbd2_journal_extend); 56 EXPORT_SYMBOL(jbd2_journal_stop); 57 EXPORT_SYMBOL(jbd2_journal_lock_updates); 58 EXPORT_SYMBOL(jbd2_journal_unlock_updates); 59 EXPORT_SYMBOL(jbd2_journal_get_write_access); 60 EXPORT_SYMBOL(jbd2_journal_get_create_access); 61 EXPORT_SYMBOL(jbd2_journal_get_undo_access); 62 EXPORT_SYMBOL(jbd2_journal_set_triggers); 63 EXPORT_SYMBOL(jbd2_journal_dirty_metadata); 64 EXPORT_SYMBOL(jbd2_journal_release_buffer); 65 EXPORT_SYMBOL(jbd2_journal_forget); 66 #if 0 67 EXPORT_SYMBOL(journal_sync_buffer); 68 #endif 69 EXPORT_SYMBOL(jbd2_journal_flush); 70 EXPORT_SYMBOL(jbd2_journal_revoke); 71 72 EXPORT_SYMBOL(jbd2_journal_init_dev); 73 EXPORT_SYMBOL(jbd2_journal_init_inode); 74 EXPORT_SYMBOL(jbd2_journal_update_format); 75 EXPORT_SYMBOL(jbd2_journal_check_used_features); 76 EXPORT_SYMBOL(jbd2_journal_check_available_features); 77 EXPORT_SYMBOL(jbd2_journal_set_features); 78 EXPORT_SYMBOL(jbd2_journal_load); 79 EXPORT_SYMBOL(jbd2_journal_destroy); 80 EXPORT_SYMBOL(jbd2_journal_abort); 81 EXPORT_SYMBOL(jbd2_journal_errno); 82 EXPORT_SYMBOL(jbd2_journal_ack_err); 83 EXPORT_SYMBOL(jbd2_journal_clear_err); 84 EXPORT_SYMBOL(jbd2_log_wait_commit); 85 EXPORT_SYMBOL(jbd2_log_start_commit); 86 EXPORT_SYMBOL(jbd2_journal_start_commit); 87 EXPORT_SYMBOL(jbd2_journal_force_commit_nested); 88 EXPORT_SYMBOL(jbd2_journal_wipe); 89 EXPORT_SYMBOL(jbd2_journal_blocks_per_page); 90 EXPORT_SYMBOL(jbd2_journal_invalidatepage); 91 EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers); 92 EXPORT_SYMBOL(jbd2_journal_force_commit); 93 EXPORT_SYMBOL(jbd2_journal_file_inode); 94 EXPORT_SYMBOL(jbd2_journal_init_jbd_inode); 95 EXPORT_SYMBOL(jbd2_journal_release_jbd_inode); 96 EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate); 97 EXPORT_SYMBOL(jbd2_inode_cache); 98 99 static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *); 100 static void __journal_abort_soft (journal_t *journal, int errno); 101 static int jbd2_journal_create_slab(size_t slab_size); 102 103 /* 104 * Helper function used to manage commit timeouts 105 */ 106 107 static void commit_timeout(unsigned long __data) 108 { 109 struct task_struct * p = (struct task_struct *) __data; 110 111 wake_up_process(p); 112 } 113 114 /* 115 * kjournald2: The main thread function used to manage a logging device 116 * journal. 117 * 118 * This kernel thread is responsible for two things: 119 * 120 * 1) COMMIT: Every so often we need to commit the current state of the 121 * filesystem to disk. The journal thread is responsible for writing 122 * all of the metadata buffers to disk. 123 * 124 * 2) CHECKPOINT: We cannot reuse a used section of the log file until all 125 * of the data in that part of the log has been rewritten elsewhere on 126 * the disk. Flushing these old buffers to reclaim space in the log is 127 * known as checkpointing, and this thread is responsible for that job. 128 */ 129 130 static int kjournald2(void *arg) 131 { 132 journal_t *journal = arg; 133 transaction_t *transaction; 134 135 /* 136 * Set up an interval timer which can be used to trigger a commit wakeup 137 * after the commit interval expires 138 */ 139 setup_timer(&journal->j_commit_timer, commit_timeout, 140 (unsigned long)current); 141 142 /* Record that the journal thread is running */ 143 journal->j_task = current; 144 wake_up(&journal->j_wait_done_commit); 145 146 /* 147 * And now, wait forever for commit wakeup events. 148 */ 149 write_lock(&journal->j_state_lock); 150 151 loop: 152 if (journal->j_flags & JBD2_UNMOUNT) 153 goto end_loop; 154 155 jbd_debug(1, "commit_sequence=%d, commit_request=%d\n", 156 journal->j_commit_sequence, journal->j_commit_request); 157 158 if (journal->j_commit_sequence != journal->j_commit_request) { 159 jbd_debug(1, "OK, requests differ\n"); 160 write_unlock(&journal->j_state_lock); 161 del_timer_sync(&journal->j_commit_timer); 162 jbd2_journal_commit_transaction(journal); 163 write_lock(&journal->j_state_lock); 164 goto loop; 165 } 166 167 wake_up(&journal->j_wait_done_commit); 168 if (freezing(current)) { 169 /* 170 * The simpler the better. Flushing journal isn't a 171 * good idea, because that depends on threads that may 172 * be already stopped. 173 */ 174 jbd_debug(1, "Now suspending kjournald2\n"); 175 write_unlock(&journal->j_state_lock); 176 refrigerator(); 177 write_lock(&journal->j_state_lock); 178 } else { 179 /* 180 * We assume on resume that commits are already there, 181 * so we don't sleep 182 */ 183 DEFINE_WAIT(wait); 184 int should_sleep = 1; 185 186 prepare_to_wait(&journal->j_wait_commit, &wait, 187 TASK_INTERRUPTIBLE); 188 if (journal->j_commit_sequence != journal->j_commit_request) 189 should_sleep = 0; 190 transaction = journal->j_running_transaction; 191 if (transaction && time_after_eq(jiffies, 192 transaction->t_expires)) 193 should_sleep = 0; 194 if (journal->j_flags & JBD2_UNMOUNT) 195 should_sleep = 0; 196 if (should_sleep) { 197 write_unlock(&journal->j_state_lock); 198 schedule(); 199 write_lock(&journal->j_state_lock); 200 } 201 finish_wait(&journal->j_wait_commit, &wait); 202 } 203 204 jbd_debug(1, "kjournald2 wakes\n"); 205 206 /* 207 * Were we woken up by a commit wakeup event? 208 */ 209 transaction = journal->j_running_transaction; 210 if (transaction && time_after_eq(jiffies, transaction->t_expires)) { 211 journal->j_commit_request = transaction->t_tid; 212 jbd_debug(1, "woke because of timeout\n"); 213 } 214 goto loop; 215 216 end_loop: 217 write_unlock(&journal->j_state_lock); 218 del_timer_sync(&journal->j_commit_timer); 219 journal->j_task = NULL; 220 wake_up(&journal->j_wait_done_commit); 221 jbd_debug(1, "Journal thread exiting.\n"); 222 return 0; 223 } 224 225 static int jbd2_journal_start_thread(journal_t *journal) 226 { 227 struct task_struct *t; 228 229 t = kthread_run(kjournald2, journal, "jbd2/%s", 230 journal->j_devname); 231 if (IS_ERR(t)) 232 return PTR_ERR(t); 233 234 wait_event(journal->j_wait_done_commit, journal->j_task != NULL); 235 return 0; 236 } 237 238 static void journal_kill_thread(journal_t *journal) 239 { 240 write_lock(&journal->j_state_lock); 241 journal->j_flags |= JBD2_UNMOUNT; 242 243 while (journal->j_task) { 244 wake_up(&journal->j_wait_commit); 245 write_unlock(&journal->j_state_lock); 246 wait_event(journal->j_wait_done_commit, journal->j_task == NULL); 247 write_lock(&journal->j_state_lock); 248 } 249 write_unlock(&journal->j_state_lock); 250 } 251 252 /* 253 * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal. 254 * 255 * Writes a metadata buffer to a given disk block. The actual IO is not 256 * performed but a new buffer_head is constructed which labels the data 257 * to be written with the correct destination disk block. 258 * 259 * Any magic-number escaping which needs to be done will cause a 260 * copy-out here. If the buffer happens to start with the 261 * JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the 262 * magic number is only written to the log for descripter blocks. In 263 * this case, we copy the data and replace the first word with 0, and we 264 * return a result code which indicates that this buffer needs to be 265 * marked as an escaped buffer in the corresponding log descriptor 266 * block. The missing word can then be restored when the block is read 267 * during recovery. 268 * 269 * If the source buffer has already been modified by a new transaction 270 * since we took the last commit snapshot, we use the frozen copy of 271 * that data for IO. If we end up using the existing buffer_head's data 272 * for the write, then we *have* to lock the buffer to prevent anyone 273 * else from using and possibly modifying it while the IO is in 274 * progress. 275 * 276 * The function returns a pointer to the buffer_heads to be used for IO. 277 * 278 * We assume that the journal has already been locked in this function. 279 * 280 * Return value: 281 * <0: Error 282 * >=0: Finished OK 283 * 284 * On success: 285 * Bit 0 set == escape performed on the data 286 * Bit 1 set == buffer copy-out performed (kfree the data after IO) 287 */ 288 289 int jbd2_journal_write_metadata_buffer(transaction_t *transaction, 290 struct journal_head *jh_in, 291 struct journal_head **jh_out, 292 unsigned long long blocknr) 293 { 294 int need_copy_out = 0; 295 int done_copy_out = 0; 296 int do_escape = 0; 297 char *mapped_data; 298 struct buffer_head *new_bh; 299 struct journal_head *new_jh; 300 struct page *new_page; 301 unsigned int new_offset; 302 struct buffer_head *bh_in = jh2bh(jh_in); 303 journal_t *journal = transaction->t_journal; 304 305 /* 306 * The buffer really shouldn't be locked: only the current committing 307 * transaction is allowed to write it, so nobody else is allowed 308 * to do any IO. 309 * 310 * akpm: except if we're journalling data, and write() output is 311 * also part of a shared mapping, and another thread has 312 * decided to launch a writepage() against this buffer. 313 */ 314 J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in)); 315 316 retry_alloc: 317 new_bh = alloc_buffer_head(GFP_NOFS); 318 if (!new_bh) { 319 /* 320 * Failure is not an option, but __GFP_NOFAIL is going 321 * away; so we retry ourselves here. 322 */ 323 congestion_wait(BLK_RW_ASYNC, HZ/50); 324 goto retry_alloc; 325 } 326 327 /* keep subsequent assertions sane */ 328 new_bh->b_state = 0; 329 init_buffer(new_bh, NULL, NULL); 330 atomic_set(&new_bh->b_count, 1); 331 new_jh = jbd2_journal_add_journal_head(new_bh); /* This sleeps */ 332 333 /* 334 * If a new transaction has already done a buffer copy-out, then 335 * we use that version of the data for the commit. 336 */ 337 jbd_lock_bh_state(bh_in); 338 repeat: 339 if (jh_in->b_frozen_data) { 340 done_copy_out = 1; 341 new_page = virt_to_page(jh_in->b_frozen_data); 342 new_offset = offset_in_page(jh_in->b_frozen_data); 343 } else { 344 new_page = jh2bh(jh_in)->b_page; 345 new_offset = offset_in_page(jh2bh(jh_in)->b_data); 346 } 347 348 mapped_data = kmap_atomic(new_page, KM_USER0); 349 /* 350 * Fire data frozen trigger if data already wasn't frozen. Do this 351 * before checking for escaping, as the trigger may modify the magic 352 * offset. If a copy-out happens afterwards, it will have the correct 353 * data in the buffer. 354 */ 355 if (!done_copy_out) 356 jbd2_buffer_frozen_trigger(jh_in, mapped_data + new_offset, 357 jh_in->b_triggers); 358 359 /* 360 * Check for escaping 361 */ 362 if (*((__be32 *)(mapped_data + new_offset)) == 363 cpu_to_be32(JBD2_MAGIC_NUMBER)) { 364 need_copy_out = 1; 365 do_escape = 1; 366 } 367 kunmap_atomic(mapped_data, KM_USER0); 368 369 /* 370 * Do we need to do a data copy? 371 */ 372 if (need_copy_out && !done_copy_out) { 373 char *tmp; 374 375 jbd_unlock_bh_state(bh_in); 376 tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS); 377 if (!tmp) { 378 jbd2_journal_put_journal_head(new_jh); 379 return -ENOMEM; 380 } 381 jbd_lock_bh_state(bh_in); 382 if (jh_in->b_frozen_data) { 383 jbd2_free(tmp, bh_in->b_size); 384 goto repeat; 385 } 386 387 jh_in->b_frozen_data = tmp; 388 mapped_data = kmap_atomic(new_page, KM_USER0); 389 memcpy(tmp, mapped_data + new_offset, jh2bh(jh_in)->b_size); 390 kunmap_atomic(mapped_data, KM_USER0); 391 392 new_page = virt_to_page(tmp); 393 new_offset = offset_in_page(tmp); 394 done_copy_out = 1; 395 396 /* 397 * This isn't strictly necessary, as we're using frozen 398 * data for the escaping, but it keeps consistency with 399 * b_frozen_data usage. 400 */ 401 jh_in->b_frozen_triggers = jh_in->b_triggers; 402 } 403 404 /* 405 * Did we need to do an escaping? Now we've done all the 406 * copying, we can finally do so. 407 */ 408 if (do_escape) { 409 mapped_data = kmap_atomic(new_page, KM_USER0); 410 *((unsigned int *)(mapped_data + new_offset)) = 0; 411 kunmap_atomic(mapped_data, KM_USER0); 412 } 413 414 set_bh_page(new_bh, new_page, new_offset); 415 new_jh->b_transaction = NULL; 416 new_bh->b_size = jh2bh(jh_in)->b_size; 417 new_bh->b_bdev = transaction->t_journal->j_dev; 418 new_bh->b_blocknr = blocknr; 419 set_buffer_mapped(new_bh); 420 set_buffer_dirty(new_bh); 421 422 *jh_out = new_jh; 423 424 /* 425 * The to-be-written buffer needs to get moved to the io queue, 426 * and the original buffer whose contents we are shadowing or 427 * copying is moved to the transaction's shadow queue. 428 */ 429 JBUFFER_TRACE(jh_in, "file as BJ_Shadow"); 430 spin_lock(&journal->j_list_lock); 431 __jbd2_journal_file_buffer(jh_in, transaction, BJ_Shadow); 432 spin_unlock(&journal->j_list_lock); 433 jbd_unlock_bh_state(bh_in); 434 435 JBUFFER_TRACE(new_jh, "file as BJ_IO"); 436 jbd2_journal_file_buffer(new_jh, transaction, BJ_IO); 437 438 return do_escape | (done_copy_out << 1); 439 } 440 441 /* 442 * Allocation code for the journal file. Manage the space left in the 443 * journal, so that we can begin checkpointing when appropriate. 444 */ 445 446 /* 447 * __jbd2_log_space_left: Return the number of free blocks left in the journal. 448 * 449 * Called with the journal already locked. 450 * 451 * Called under j_state_lock 452 */ 453 454 int __jbd2_log_space_left(journal_t *journal) 455 { 456 int left = journal->j_free; 457 458 /* assert_spin_locked(&journal->j_state_lock); */ 459 460 /* 461 * Be pessimistic here about the number of those free blocks which 462 * might be required for log descriptor control blocks. 463 */ 464 465 #define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */ 466 467 left -= MIN_LOG_RESERVED_BLOCKS; 468 469 if (left <= 0) 470 return 0; 471 left -= (left >> 3); 472 return left; 473 } 474 475 /* 476 * Called with j_state_lock locked for writing. 477 * Returns true if a transaction commit was started. 478 */ 479 int __jbd2_log_start_commit(journal_t *journal, tid_t target) 480 { 481 /* 482 * Are we already doing a recent enough commit? 483 */ 484 if (!tid_geq(journal->j_commit_request, target)) { 485 /* 486 * We want a new commit: OK, mark the request and wakeup the 487 * commit thread. We do _not_ do the commit ourselves. 488 */ 489 490 journal->j_commit_request = target; 491 jbd_debug(1, "JBD: requesting commit %d/%d\n", 492 journal->j_commit_request, 493 journal->j_commit_sequence); 494 wake_up(&journal->j_wait_commit); 495 return 1; 496 } 497 return 0; 498 } 499 500 int jbd2_log_start_commit(journal_t *journal, tid_t tid) 501 { 502 int ret; 503 504 write_lock(&journal->j_state_lock); 505 ret = __jbd2_log_start_commit(journal, tid); 506 write_unlock(&journal->j_state_lock); 507 return ret; 508 } 509 510 /* 511 * Force and wait upon a commit if the calling process is not within 512 * transaction. This is used for forcing out undo-protected data which contains 513 * bitmaps, when the fs is running out of space. 514 * 515 * We can only force the running transaction if we don't have an active handle; 516 * otherwise, we will deadlock. 517 * 518 * Returns true if a transaction was started. 519 */ 520 int jbd2_journal_force_commit_nested(journal_t *journal) 521 { 522 transaction_t *transaction = NULL; 523 tid_t tid; 524 int need_to_start = 0; 525 526 read_lock(&journal->j_state_lock); 527 if (journal->j_running_transaction && !current->journal_info) { 528 transaction = journal->j_running_transaction; 529 if (!tid_geq(journal->j_commit_request, transaction->t_tid)) 530 need_to_start = 1; 531 } else if (journal->j_committing_transaction) 532 transaction = journal->j_committing_transaction; 533 534 if (!transaction) { 535 read_unlock(&journal->j_state_lock); 536 return 0; /* Nothing to retry */ 537 } 538 539 tid = transaction->t_tid; 540 read_unlock(&journal->j_state_lock); 541 if (need_to_start) 542 jbd2_log_start_commit(journal, tid); 543 jbd2_log_wait_commit(journal, tid); 544 return 1; 545 } 546 547 /* 548 * Start a commit of the current running transaction (if any). Returns true 549 * if a transaction is going to be committed (or is currently already 550 * committing), and fills its tid in at *ptid 551 */ 552 int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid) 553 { 554 int ret = 0; 555 556 write_lock(&journal->j_state_lock); 557 if (journal->j_running_transaction) { 558 tid_t tid = journal->j_running_transaction->t_tid; 559 560 __jbd2_log_start_commit(journal, tid); 561 /* There's a running transaction and we've just made sure 562 * it's commit has been scheduled. */ 563 if (ptid) 564 *ptid = tid; 565 ret = 1; 566 } else if (journal->j_committing_transaction) { 567 /* 568 * If ext3_write_super() recently started a commit, then we 569 * have to wait for completion of that transaction 570 */ 571 if (ptid) 572 *ptid = journal->j_committing_transaction->t_tid; 573 ret = 1; 574 } 575 write_unlock(&journal->j_state_lock); 576 return ret; 577 } 578 579 /* 580 * Wait for a specified commit to complete. 581 * The caller may not hold the journal lock. 582 */ 583 int jbd2_log_wait_commit(journal_t *journal, tid_t tid) 584 { 585 int err = 0; 586 587 read_lock(&journal->j_state_lock); 588 #ifdef CONFIG_JBD2_DEBUG 589 if (!tid_geq(journal->j_commit_request, tid)) { 590 printk(KERN_EMERG 591 "%s: error: j_commit_request=%d, tid=%d\n", 592 __func__, journal->j_commit_request, tid); 593 } 594 #endif 595 while (tid_gt(tid, journal->j_commit_sequence)) { 596 jbd_debug(1, "JBD: want %d, j_commit_sequence=%d\n", 597 tid, journal->j_commit_sequence); 598 wake_up(&journal->j_wait_commit); 599 read_unlock(&journal->j_state_lock); 600 wait_event(journal->j_wait_done_commit, 601 !tid_gt(tid, journal->j_commit_sequence)); 602 read_lock(&journal->j_state_lock); 603 } 604 read_unlock(&journal->j_state_lock); 605 606 if (unlikely(is_journal_aborted(journal))) { 607 printk(KERN_EMERG "journal commit I/O error\n"); 608 err = -EIO; 609 } 610 return err; 611 } 612 613 /* 614 * Log buffer allocation routines: 615 */ 616 617 int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp) 618 { 619 unsigned long blocknr; 620 621 write_lock(&journal->j_state_lock); 622 J_ASSERT(journal->j_free > 1); 623 624 blocknr = journal->j_head; 625 journal->j_head++; 626 journal->j_free--; 627 if (journal->j_head == journal->j_last) 628 journal->j_head = journal->j_first; 629 write_unlock(&journal->j_state_lock); 630 return jbd2_journal_bmap(journal, blocknr, retp); 631 } 632 633 /* 634 * Conversion of logical to physical block numbers for the journal 635 * 636 * On external journals the journal blocks are identity-mapped, so 637 * this is a no-op. If needed, we can use j_blk_offset - everything is 638 * ready. 639 */ 640 int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr, 641 unsigned long long *retp) 642 { 643 int err = 0; 644 unsigned long long ret; 645 646 if (journal->j_inode) { 647 ret = bmap(journal->j_inode, blocknr); 648 if (ret) 649 *retp = ret; 650 else { 651 printk(KERN_ALERT "%s: journal block not found " 652 "at offset %lu on %s\n", 653 __func__, blocknr, journal->j_devname); 654 err = -EIO; 655 __journal_abort_soft(journal, err); 656 } 657 } else { 658 *retp = blocknr; /* +journal->j_blk_offset */ 659 } 660 return err; 661 } 662 663 /* 664 * We play buffer_head aliasing tricks to write data/metadata blocks to 665 * the journal without copying their contents, but for journal 666 * descriptor blocks we do need to generate bona fide buffers. 667 * 668 * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying 669 * the buffer's contents they really should run flush_dcache_page(bh->b_page). 670 * But we don't bother doing that, so there will be coherency problems with 671 * mmaps of blockdevs which hold live JBD-controlled filesystems. 672 */ 673 struct journal_head *jbd2_journal_get_descriptor_buffer(journal_t *journal) 674 { 675 struct buffer_head *bh; 676 unsigned long long blocknr; 677 int err; 678 679 err = jbd2_journal_next_log_block(journal, &blocknr); 680 681 if (err) 682 return NULL; 683 684 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); 685 if (!bh) 686 return NULL; 687 lock_buffer(bh); 688 memset(bh->b_data, 0, journal->j_blocksize); 689 set_buffer_uptodate(bh); 690 unlock_buffer(bh); 691 BUFFER_TRACE(bh, "return this buffer"); 692 return jbd2_journal_add_journal_head(bh); 693 } 694 695 struct jbd2_stats_proc_session { 696 journal_t *journal; 697 struct transaction_stats_s *stats; 698 int start; 699 int max; 700 }; 701 702 static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos) 703 { 704 return *pos ? NULL : SEQ_START_TOKEN; 705 } 706 707 static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos) 708 { 709 return NULL; 710 } 711 712 static int jbd2_seq_info_show(struct seq_file *seq, void *v) 713 { 714 struct jbd2_stats_proc_session *s = seq->private; 715 716 if (v != SEQ_START_TOKEN) 717 return 0; 718 seq_printf(seq, "%lu transaction, each up to %u blocks\n", 719 s->stats->ts_tid, 720 s->journal->j_max_transaction_buffers); 721 if (s->stats->ts_tid == 0) 722 return 0; 723 seq_printf(seq, "average: \n %ums waiting for transaction\n", 724 jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid)); 725 seq_printf(seq, " %ums running transaction\n", 726 jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid)); 727 seq_printf(seq, " %ums transaction was being locked\n", 728 jiffies_to_msecs(s->stats->run.rs_locked / s->stats->ts_tid)); 729 seq_printf(seq, " %ums flushing data (in ordered mode)\n", 730 jiffies_to_msecs(s->stats->run.rs_flushing / s->stats->ts_tid)); 731 seq_printf(seq, " %ums logging transaction\n", 732 jiffies_to_msecs(s->stats->run.rs_logging / s->stats->ts_tid)); 733 seq_printf(seq, " %lluus average transaction commit time\n", 734 div_u64(s->journal->j_average_commit_time, 1000)); 735 seq_printf(seq, " %lu handles per transaction\n", 736 s->stats->run.rs_handle_count / s->stats->ts_tid); 737 seq_printf(seq, " %lu blocks per transaction\n", 738 s->stats->run.rs_blocks / s->stats->ts_tid); 739 seq_printf(seq, " %lu logged blocks per transaction\n", 740 s->stats->run.rs_blocks_logged / s->stats->ts_tid); 741 return 0; 742 } 743 744 static void jbd2_seq_info_stop(struct seq_file *seq, void *v) 745 { 746 } 747 748 static const struct seq_operations jbd2_seq_info_ops = { 749 .start = jbd2_seq_info_start, 750 .next = jbd2_seq_info_next, 751 .stop = jbd2_seq_info_stop, 752 .show = jbd2_seq_info_show, 753 }; 754 755 static int jbd2_seq_info_open(struct inode *inode, struct file *file) 756 { 757 journal_t *journal = PDE(inode)->data; 758 struct jbd2_stats_proc_session *s; 759 int rc, size; 760 761 s = kmalloc(sizeof(*s), GFP_KERNEL); 762 if (s == NULL) 763 return -ENOMEM; 764 size = sizeof(struct transaction_stats_s); 765 s->stats = kmalloc(size, GFP_KERNEL); 766 if (s->stats == NULL) { 767 kfree(s); 768 return -ENOMEM; 769 } 770 spin_lock(&journal->j_history_lock); 771 memcpy(s->stats, &journal->j_stats, size); 772 s->journal = journal; 773 spin_unlock(&journal->j_history_lock); 774 775 rc = seq_open(file, &jbd2_seq_info_ops); 776 if (rc == 0) { 777 struct seq_file *m = file->private_data; 778 m->private = s; 779 } else { 780 kfree(s->stats); 781 kfree(s); 782 } 783 return rc; 784 785 } 786 787 static int jbd2_seq_info_release(struct inode *inode, struct file *file) 788 { 789 struct seq_file *seq = file->private_data; 790 struct jbd2_stats_proc_session *s = seq->private; 791 kfree(s->stats); 792 kfree(s); 793 return seq_release(inode, file); 794 } 795 796 static const struct file_operations jbd2_seq_info_fops = { 797 .owner = THIS_MODULE, 798 .open = jbd2_seq_info_open, 799 .read = seq_read, 800 .llseek = seq_lseek, 801 .release = jbd2_seq_info_release, 802 }; 803 804 static struct proc_dir_entry *proc_jbd2_stats; 805 806 static void jbd2_stats_proc_init(journal_t *journal) 807 { 808 journal->j_proc_entry = proc_mkdir(journal->j_devname, proc_jbd2_stats); 809 if (journal->j_proc_entry) { 810 proc_create_data("info", S_IRUGO, journal->j_proc_entry, 811 &jbd2_seq_info_fops, journal); 812 } 813 } 814 815 static void jbd2_stats_proc_exit(journal_t *journal) 816 { 817 remove_proc_entry("info", journal->j_proc_entry); 818 remove_proc_entry(journal->j_devname, proc_jbd2_stats); 819 } 820 821 /* 822 * Management for journal control blocks: functions to create and 823 * destroy journal_t structures, and to initialise and read existing 824 * journal blocks from disk. */ 825 826 /* First: create and setup a journal_t object in memory. We initialise 827 * very few fields yet: that has to wait until we have created the 828 * journal structures from from scratch, or loaded them from disk. */ 829 830 static journal_t * journal_init_common (void) 831 { 832 journal_t *journal; 833 int err; 834 835 journal = kzalloc(sizeof(*journal), GFP_KERNEL); 836 if (!journal) 837 return NULL; 838 839 init_waitqueue_head(&journal->j_wait_transaction_locked); 840 init_waitqueue_head(&journal->j_wait_logspace); 841 init_waitqueue_head(&journal->j_wait_done_commit); 842 init_waitqueue_head(&journal->j_wait_checkpoint); 843 init_waitqueue_head(&journal->j_wait_commit); 844 init_waitqueue_head(&journal->j_wait_updates); 845 mutex_init(&journal->j_barrier); 846 mutex_init(&journal->j_checkpoint_mutex); 847 spin_lock_init(&journal->j_revoke_lock); 848 spin_lock_init(&journal->j_list_lock); 849 rwlock_init(&journal->j_state_lock); 850 851 journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE); 852 journal->j_min_batch_time = 0; 853 journal->j_max_batch_time = 15000; /* 15ms */ 854 855 /* The journal is marked for error until we succeed with recovery! */ 856 journal->j_flags = JBD2_ABORT; 857 858 /* Set up a default-sized revoke table for the new mount. */ 859 err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH); 860 if (err) { 861 kfree(journal); 862 return NULL; 863 } 864 865 spin_lock_init(&journal->j_history_lock); 866 867 return journal; 868 } 869 870 /* jbd2_journal_init_dev and jbd2_journal_init_inode: 871 * 872 * Create a journal structure assigned some fixed set of disk blocks to 873 * the journal. We don't actually touch those disk blocks yet, but we 874 * need to set up all of the mapping information to tell the journaling 875 * system where the journal blocks are. 876 * 877 */ 878 879 /** 880 * journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure 881 * @bdev: Block device on which to create the journal 882 * @fs_dev: Device which hold journalled filesystem for this journal. 883 * @start: Block nr Start of journal. 884 * @len: Length of the journal in blocks. 885 * @blocksize: blocksize of journalling device 886 * 887 * Returns: a newly created journal_t * 888 * 889 * jbd2_journal_init_dev creates a journal which maps a fixed contiguous 890 * range of blocks on an arbitrary block device. 891 * 892 */ 893 journal_t * jbd2_journal_init_dev(struct block_device *bdev, 894 struct block_device *fs_dev, 895 unsigned long long start, int len, int blocksize) 896 { 897 journal_t *journal = journal_init_common(); 898 struct buffer_head *bh; 899 char *p; 900 int n; 901 902 if (!journal) 903 return NULL; 904 905 /* journal descriptor can store up to n blocks -bzzz */ 906 journal->j_blocksize = blocksize; 907 journal->j_dev = bdev; 908 journal->j_fs_dev = fs_dev; 909 journal->j_blk_offset = start; 910 journal->j_maxlen = len; 911 bdevname(journal->j_dev, journal->j_devname); 912 p = journal->j_devname; 913 while ((p = strchr(p, '/'))) 914 *p = '!'; 915 jbd2_stats_proc_init(journal); 916 n = journal->j_blocksize / sizeof(journal_block_tag_t); 917 journal->j_wbufsize = n; 918 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL); 919 if (!journal->j_wbuf) { 920 printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n", 921 __func__); 922 goto out_err; 923 } 924 925 bh = __getblk(journal->j_dev, start, journal->j_blocksize); 926 if (!bh) { 927 printk(KERN_ERR 928 "%s: Cannot get buffer for journal superblock\n", 929 __func__); 930 goto out_err; 931 } 932 journal->j_sb_buffer = bh; 933 journal->j_superblock = (journal_superblock_t *)bh->b_data; 934 935 return journal; 936 out_err: 937 kfree(journal->j_wbuf); 938 jbd2_stats_proc_exit(journal); 939 kfree(journal); 940 return NULL; 941 } 942 943 /** 944 * journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode. 945 * @inode: An inode to create the journal in 946 * 947 * jbd2_journal_init_inode creates a journal which maps an on-disk inode as 948 * the journal. The inode must exist already, must support bmap() and 949 * must have all data blocks preallocated. 950 */ 951 journal_t * jbd2_journal_init_inode (struct inode *inode) 952 { 953 struct buffer_head *bh; 954 journal_t *journal = journal_init_common(); 955 char *p; 956 int err; 957 int n; 958 unsigned long long blocknr; 959 960 if (!journal) 961 return NULL; 962 963 journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev; 964 journal->j_inode = inode; 965 bdevname(journal->j_dev, journal->j_devname); 966 p = journal->j_devname; 967 while ((p = strchr(p, '/'))) 968 *p = '!'; 969 p = journal->j_devname + strlen(journal->j_devname); 970 sprintf(p, "-%lu", journal->j_inode->i_ino); 971 jbd_debug(1, 972 "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n", 973 journal, inode->i_sb->s_id, inode->i_ino, 974 (long long) inode->i_size, 975 inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize); 976 977 journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits; 978 journal->j_blocksize = inode->i_sb->s_blocksize; 979 jbd2_stats_proc_init(journal); 980 981 /* journal descriptor can store up to n blocks -bzzz */ 982 n = journal->j_blocksize / sizeof(journal_block_tag_t); 983 journal->j_wbufsize = n; 984 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL); 985 if (!journal->j_wbuf) { 986 printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n", 987 __func__); 988 goto out_err; 989 } 990 991 err = jbd2_journal_bmap(journal, 0, &blocknr); 992 /* If that failed, give up */ 993 if (err) { 994 printk(KERN_ERR "%s: Cannnot locate journal superblock\n", 995 __func__); 996 goto out_err; 997 } 998 999 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); 1000 if (!bh) { 1001 printk(KERN_ERR 1002 "%s: Cannot get buffer for journal superblock\n", 1003 __func__); 1004 goto out_err; 1005 } 1006 journal->j_sb_buffer = bh; 1007 journal->j_superblock = (journal_superblock_t *)bh->b_data; 1008 1009 return journal; 1010 out_err: 1011 kfree(journal->j_wbuf); 1012 jbd2_stats_proc_exit(journal); 1013 kfree(journal); 1014 return NULL; 1015 } 1016 1017 /* 1018 * If the journal init or create aborts, we need to mark the journal 1019 * superblock as being NULL to prevent the journal destroy from writing 1020 * back a bogus superblock. 1021 */ 1022 static void journal_fail_superblock (journal_t *journal) 1023 { 1024 struct buffer_head *bh = journal->j_sb_buffer; 1025 brelse(bh); 1026 journal->j_sb_buffer = NULL; 1027 } 1028 1029 /* 1030 * Given a journal_t structure, initialise the various fields for 1031 * startup of a new journaling session. We use this both when creating 1032 * a journal, and after recovering an old journal to reset it for 1033 * subsequent use. 1034 */ 1035 1036 static int journal_reset(journal_t *journal) 1037 { 1038 journal_superblock_t *sb = journal->j_superblock; 1039 unsigned long long first, last; 1040 1041 first = be32_to_cpu(sb->s_first); 1042 last = be32_to_cpu(sb->s_maxlen); 1043 if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) { 1044 printk(KERN_ERR "JBD: Journal too short (blocks %llu-%llu).\n", 1045 first, last); 1046 journal_fail_superblock(journal); 1047 return -EINVAL; 1048 } 1049 1050 journal->j_first = first; 1051 journal->j_last = last; 1052 1053 journal->j_head = first; 1054 journal->j_tail = first; 1055 journal->j_free = last - first; 1056 1057 journal->j_tail_sequence = journal->j_transaction_sequence; 1058 journal->j_commit_sequence = journal->j_transaction_sequence - 1; 1059 journal->j_commit_request = journal->j_commit_sequence; 1060 1061 journal->j_max_transaction_buffers = journal->j_maxlen / 4; 1062 1063 /* Add the dynamic fields and write it to disk. */ 1064 jbd2_journal_update_superblock(journal, 1); 1065 return jbd2_journal_start_thread(journal); 1066 } 1067 1068 /** 1069 * void jbd2_journal_update_superblock() - Update journal sb on disk. 1070 * @journal: The journal to update. 1071 * @wait: Set to '0' if you don't want to wait for IO completion. 1072 * 1073 * Update a journal's dynamic superblock fields and write it to disk, 1074 * optionally waiting for the IO to complete. 1075 */ 1076 void jbd2_journal_update_superblock(journal_t *journal, int wait) 1077 { 1078 journal_superblock_t *sb = journal->j_superblock; 1079 struct buffer_head *bh = journal->j_sb_buffer; 1080 1081 /* 1082 * As a special case, if the on-disk copy is already marked as needing 1083 * no recovery (s_start == 0) and there are no outstanding transactions 1084 * in the filesystem, then we can safely defer the superblock update 1085 * until the next commit by setting JBD2_FLUSHED. This avoids 1086 * attempting a write to a potential-readonly device. 1087 */ 1088 if (sb->s_start == 0 && journal->j_tail_sequence == 1089 journal->j_transaction_sequence) { 1090 jbd_debug(1,"JBD: Skipping superblock update on recovered sb " 1091 "(start %ld, seq %d, errno %d)\n", 1092 journal->j_tail, journal->j_tail_sequence, 1093 journal->j_errno); 1094 goto out; 1095 } 1096 1097 if (buffer_write_io_error(bh)) { 1098 /* 1099 * Oh, dear. A previous attempt to write the journal 1100 * superblock failed. This could happen because the 1101 * USB device was yanked out. Or it could happen to 1102 * be a transient write error and maybe the block will 1103 * be remapped. Nothing we can do but to retry the 1104 * write and hope for the best. 1105 */ 1106 printk(KERN_ERR "JBD2: previous I/O error detected " 1107 "for journal superblock update for %s.\n", 1108 journal->j_devname); 1109 clear_buffer_write_io_error(bh); 1110 set_buffer_uptodate(bh); 1111 } 1112 1113 read_lock(&journal->j_state_lock); 1114 jbd_debug(1,"JBD: updating superblock (start %ld, seq %d, errno %d)\n", 1115 journal->j_tail, journal->j_tail_sequence, journal->j_errno); 1116 1117 sb->s_sequence = cpu_to_be32(journal->j_tail_sequence); 1118 sb->s_start = cpu_to_be32(journal->j_tail); 1119 sb->s_errno = cpu_to_be32(journal->j_errno); 1120 read_unlock(&journal->j_state_lock); 1121 1122 BUFFER_TRACE(bh, "marking dirty"); 1123 mark_buffer_dirty(bh); 1124 if (wait) { 1125 sync_dirty_buffer(bh); 1126 if (buffer_write_io_error(bh)) { 1127 printk(KERN_ERR "JBD2: I/O error detected " 1128 "when updating journal superblock for %s.\n", 1129 journal->j_devname); 1130 clear_buffer_write_io_error(bh); 1131 set_buffer_uptodate(bh); 1132 } 1133 } else 1134 write_dirty_buffer(bh, WRITE); 1135 1136 out: 1137 /* If we have just flushed the log (by marking s_start==0), then 1138 * any future commit will have to be careful to update the 1139 * superblock again to re-record the true start of the log. */ 1140 1141 write_lock(&journal->j_state_lock); 1142 if (sb->s_start) 1143 journal->j_flags &= ~JBD2_FLUSHED; 1144 else 1145 journal->j_flags |= JBD2_FLUSHED; 1146 write_unlock(&journal->j_state_lock); 1147 } 1148 1149 /* 1150 * Read the superblock for a given journal, performing initial 1151 * validation of the format. 1152 */ 1153 1154 static int journal_get_superblock(journal_t *journal) 1155 { 1156 struct buffer_head *bh; 1157 journal_superblock_t *sb; 1158 int err = -EIO; 1159 1160 bh = journal->j_sb_buffer; 1161 1162 J_ASSERT(bh != NULL); 1163 if (!buffer_uptodate(bh)) { 1164 ll_rw_block(READ, 1, &bh); 1165 wait_on_buffer(bh); 1166 if (!buffer_uptodate(bh)) { 1167 printk (KERN_ERR 1168 "JBD: IO error reading journal superblock\n"); 1169 goto out; 1170 } 1171 } 1172 1173 sb = journal->j_superblock; 1174 1175 err = -EINVAL; 1176 1177 if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) || 1178 sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) { 1179 printk(KERN_WARNING "JBD: no valid journal superblock found\n"); 1180 goto out; 1181 } 1182 1183 switch(be32_to_cpu(sb->s_header.h_blocktype)) { 1184 case JBD2_SUPERBLOCK_V1: 1185 journal->j_format_version = 1; 1186 break; 1187 case JBD2_SUPERBLOCK_V2: 1188 journal->j_format_version = 2; 1189 break; 1190 default: 1191 printk(KERN_WARNING "JBD: unrecognised superblock format ID\n"); 1192 goto out; 1193 } 1194 1195 if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen) 1196 journal->j_maxlen = be32_to_cpu(sb->s_maxlen); 1197 else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) { 1198 printk (KERN_WARNING "JBD: journal file too short\n"); 1199 goto out; 1200 } 1201 1202 return 0; 1203 1204 out: 1205 journal_fail_superblock(journal); 1206 return err; 1207 } 1208 1209 /* 1210 * Load the on-disk journal superblock and read the key fields into the 1211 * journal_t. 1212 */ 1213 1214 static int load_superblock(journal_t *journal) 1215 { 1216 int err; 1217 journal_superblock_t *sb; 1218 1219 err = journal_get_superblock(journal); 1220 if (err) 1221 return err; 1222 1223 sb = journal->j_superblock; 1224 1225 journal->j_tail_sequence = be32_to_cpu(sb->s_sequence); 1226 journal->j_tail = be32_to_cpu(sb->s_start); 1227 journal->j_first = be32_to_cpu(sb->s_first); 1228 journal->j_last = be32_to_cpu(sb->s_maxlen); 1229 journal->j_errno = be32_to_cpu(sb->s_errno); 1230 1231 return 0; 1232 } 1233 1234 1235 /** 1236 * int jbd2_journal_load() - Read journal from disk. 1237 * @journal: Journal to act on. 1238 * 1239 * Given a journal_t structure which tells us which disk blocks contain 1240 * a journal, read the journal from disk to initialise the in-memory 1241 * structures. 1242 */ 1243 int jbd2_journal_load(journal_t *journal) 1244 { 1245 int err; 1246 journal_superblock_t *sb; 1247 1248 err = load_superblock(journal); 1249 if (err) 1250 return err; 1251 1252 sb = journal->j_superblock; 1253 /* If this is a V2 superblock, then we have to check the 1254 * features flags on it. */ 1255 1256 if (journal->j_format_version >= 2) { 1257 if ((sb->s_feature_ro_compat & 1258 ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) || 1259 (sb->s_feature_incompat & 1260 ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) { 1261 printk (KERN_WARNING 1262 "JBD: Unrecognised features on journal\n"); 1263 return -EINVAL; 1264 } 1265 } 1266 1267 /* 1268 * Create a slab for this blocksize 1269 */ 1270 err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize)); 1271 if (err) 1272 return err; 1273 1274 /* Let the recovery code check whether it needs to recover any 1275 * data from the journal. */ 1276 if (jbd2_journal_recover(journal)) 1277 goto recovery_error; 1278 1279 if (journal->j_failed_commit) { 1280 printk(KERN_ERR "JBD2: journal transaction %u on %s " 1281 "is corrupt.\n", journal->j_failed_commit, 1282 journal->j_devname); 1283 return -EIO; 1284 } 1285 1286 /* OK, we've finished with the dynamic journal bits: 1287 * reinitialise the dynamic contents of the superblock in memory 1288 * and reset them on disk. */ 1289 if (journal_reset(journal)) 1290 goto recovery_error; 1291 1292 journal->j_flags &= ~JBD2_ABORT; 1293 journal->j_flags |= JBD2_LOADED; 1294 return 0; 1295 1296 recovery_error: 1297 printk (KERN_WARNING "JBD: recovery failed\n"); 1298 return -EIO; 1299 } 1300 1301 /** 1302 * void jbd2_journal_destroy() - Release a journal_t structure. 1303 * @journal: Journal to act on. 1304 * 1305 * Release a journal_t structure once it is no longer in use by the 1306 * journaled object. 1307 * Return <0 if we couldn't clean up the journal. 1308 */ 1309 int jbd2_journal_destroy(journal_t *journal) 1310 { 1311 int err = 0; 1312 1313 /* Wait for the commit thread to wake up and die. */ 1314 journal_kill_thread(journal); 1315 1316 /* Force a final log commit */ 1317 if (journal->j_running_transaction) 1318 jbd2_journal_commit_transaction(journal); 1319 1320 /* Force any old transactions to disk */ 1321 1322 /* Totally anal locking here... */ 1323 spin_lock(&journal->j_list_lock); 1324 while (journal->j_checkpoint_transactions != NULL) { 1325 spin_unlock(&journal->j_list_lock); 1326 mutex_lock(&journal->j_checkpoint_mutex); 1327 jbd2_log_do_checkpoint(journal); 1328 mutex_unlock(&journal->j_checkpoint_mutex); 1329 spin_lock(&journal->j_list_lock); 1330 } 1331 1332 J_ASSERT(journal->j_running_transaction == NULL); 1333 J_ASSERT(journal->j_committing_transaction == NULL); 1334 J_ASSERT(journal->j_checkpoint_transactions == NULL); 1335 spin_unlock(&journal->j_list_lock); 1336 1337 if (journal->j_sb_buffer) { 1338 if (!is_journal_aborted(journal)) { 1339 /* We can now mark the journal as empty. */ 1340 journal->j_tail = 0; 1341 journal->j_tail_sequence = 1342 ++journal->j_transaction_sequence; 1343 jbd2_journal_update_superblock(journal, 1); 1344 } else { 1345 err = -EIO; 1346 } 1347 brelse(journal->j_sb_buffer); 1348 } 1349 1350 if (journal->j_proc_entry) 1351 jbd2_stats_proc_exit(journal); 1352 if (journal->j_inode) 1353 iput(journal->j_inode); 1354 if (journal->j_revoke) 1355 jbd2_journal_destroy_revoke(journal); 1356 kfree(journal->j_wbuf); 1357 kfree(journal); 1358 1359 return err; 1360 } 1361 1362 1363 /** 1364 *int jbd2_journal_check_used_features () - Check if features specified are used. 1365 * @journal: Journal to check. 1366 * @compat: bitmask of compatible features 1367 * @ro: bitmask of features that force read-only mount 1368 * @incompat: bitmask of incompatible features 1369 * 1370 * Check whether the journal uses all of a given set of 1371 * features. Return true (non-zero) if it does. 1372 **/ 1373 1374 int jbd2_journal_check_used_features (journal_t *journal, unsigned long compat, 1375 unsigned long ro, unsigned long incompat) 1376 { 1377 journal_superblock_t *sb; 1378 1379 if (!compat && !ro && !incompat) 1380 return 1; 1381 /* Load journal superblock if it is not loaded yet. */ 1382 if (journal->j_format_version == 0 && 1383 journal_get_superblock(journal) != 0) 1384 return 0; 1385 if (journal->j_format_version == 1) 1386 return 0; 1387 1388 sb = journal->j_superblock; 1389 1390 if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) && 1391 ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) && 1392 ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat)) 1393 return 1; 1394 1395 return 0; 1396 } 1397 1398 /** 1399 * int jbd2_journal_check_available_features() - Check feature set in journalling layer 1400 * @journal: Journal to check. 1401 * @compat: bitmask of compatible features 1402 * @ro: bitmask of features that force read-only mount 1403 * @incompat: bitmask of incompatible features 1404 * 1405 * Check whether the journaling code supports the use of 1406 * all of a given set of features on this journal. Return true 1407 * (non-zero) if it can. */ 1408 1409 int jbd2_journal_check_available_features (journal_t *journal, unsigned long compat, 1410 unsigned long ro, unsigned long incompat) 1411 { 1412 if (!compat && !ro && !incompat) 1413 return 1; 1414 1415 /* We can support any known requested features iff the 1416 * superblock is in version 2. Otherwise we fail to support any 1417 * extended sb features. */ 1418 1419 if (journal->j_format_version != 2) 1420 return 0; 1421 1422 if ((compat & JBD2_KNOWN_COMPAT_FEATURES) == compat && 1423 (ro & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro && 1424 (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat) 1425 return 1; 1426 1427 return 0; 1428 } 1429 1430 /** 1431 * int jbd2_journal_set_features () - Mark a given journal feature in the superblock 1432 * @journal: Journal to act on. 1433 * @compat: bitmask of compatible features 1434 * @ro: bitmask of features that force read-only mount 1435 * @incompat: bitmask of incompatible features 1436 * 1437 * Mark a given journal feature as present on the 1438 * superblock. Returns true if the requested features could be set. 1439 * 1440 */ 1441 1442 int jbd2_journal_set_features (journal_t *journal, unsigned long compat, 1443 unsigned long ro, unsigned long incompat) 1444 { 1445 journal_superblock_t *sb; 1446 1447 if (jbd2_journal_check_used_features(journal, compat, ro, incompat)) 1448 return 1; 1449 1450 if (!jbd2_journal_check_available_features(journal, compat, ro, incompat)) 1451 return 0; 1452 1453 jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n", 1454 compat, ro, incompat); 1455 1456 sb = journal->j_superblock; 1457 1458 sb->s_feature_compat |= cpu_to_be32(compat); 1459 sb->s_feature_ro_compat |= cpu_to_be32(ro); 1460 sb->s_feature_incompat |= cpu_to_be32(incompat); 1461 1462 return 1; 1463 } 1464 1465 /* 1466 * jbd2_journal_clear_features () - Clear a given journal feature in the 1467 * superblock 1468 * @journal: Journal to act on. 1469 * @compat: bitmask of compatible features 1470 * @ro: bitmask of features that force read-only mount 1471 * @incompat: bitmask of incompatible features 1472 * 1473 * Clear a given journal feature as present on the 1474 * superblock. 1475 */ 1476 void jbd2_journal_clear_features(journal_t *journal, unsigned long compat, 1477 unsigned long ro, unsigned long incompat) 1478 { 1479 journal_superblock_t *sb; 1480 1481 jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n", 1482 compat, ro, incompat); 1483 1484 sb = journal->j_superblock; 1485 1486 sb->s_feature_compat &= ~cpu_to_be32(compat); 1487 sb->s_feature_ro_compat &= ~cpu_to_be32(ro); 1488 sb->s_feature_incompat &= ~cpu_to_be32(incompat); 1489 } 1490 EXPORT_SYMBOL(jbd2_journal_clear_features); 1491 1492 /** 1493 * int jbd2_journal_update_format () - Update on-disk journal structure. 1494 * @journal: Journal to act on. 1495 * 1496 * Given an initialised but unloaded journal struct, poke about in the 1497 * on-disk structure to update it to the most recent supported version. 1498 */ 1499 int jbd2_journal_update_format (journal_t *journal) 1500 { 1501 journal_superblock_t *sb; 1502 int err; 1503 1504 err = journal_get_superblock(journal); 1505 if (err) 1506 return err; 1507 1508 sb = journal->j_superblock; 1509 1510 switch (be32_to_cpu(sb->s_header.h_blocktype)) { 1511 case JBD2_SUPERBLOCK_V2: 1512 return 0; 1513 case JBD2_SUPERBLOCK_V1: 1514 return journal_convert_superblock_v1(journal, sb); 1515 default: 1516 break; 1517 } 1518 return -EINVAL; 1519 } 1520 1521 static int journal_convert_superblock_v1(journal_t *journal, 1522 journal_superblock_t *sb) 1523 { 1524 int offset, blocksize; 1525 struct buffer_head *bh; 1526 1527 printk(KERN_WARNING 1528 "JBD: Converting superblock from version 1 to 2.\n"); 1529 1530 /* Pre-initialise new fields to zero */ 1531 offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb); 1532 blocksize = be32_to_cpu(sb->s_blocksize); 1533 memset(&sb->s_feature_compat, 0, blocksize-offset); 1534 1535 sb->s_nr_users = cpu_to_be32(1); 1536 sb->s_header.h_blocktype = cpu_to_be32(JBD2_SUPERBLOCK_V2); 1537 journal->j_format_version = 2; 1538 1539 bh = journal->j_sb_buffer; 1540 BUFFER_TRACE(bh, "marking dirty"); 1541 mark_buffer_dirty(bh); 1542 sync_dirty_buffer(bh); 1543 return 0; 1544 } 1545 1546 1547 /** 1548 * int jbd2_journal_flush () - Flush journal 1549 * @journal: Journal to act on. 1550 * 1551 * Flush all data for a given journal to disk and empty the journal. 1552 * Filesystems can use this when remounting readonly to ensure that 1553 * recovery does not need to happen on remount. 1554 */ 1555 1556 int jbd2_journal_flush(journal_t *journal) 1557 { 1558 int err = 0; 1559 transaction_t *transaction = NULL; 1560 unsigned long old_tail; 1561 1562 write_lock(&journal->j_state_lock); 1563 1564 /* Force everything buffered to the log... */ 1565 if (journal->j_running_transaction) { 1566 transaction = journal->j_running_transaction; 1567 __jbd2_log_start_commit(journal, transaction->t_tid); 1568 } else if (journal->j_committing_transaction) 1569 transaction = journal->j_committing_transaction; 1570 1571 /* Wait for the log commit to complete... */ 1572 if (transaction) { 1573 tid_t tid = transaction->t_tid; 1574 1575 write_unlock(&journal->j_state_lock); 1576 jbd2_log_wait_commit(journal, tid); 1577 } else { 1578 write_unlock(&journal->j_state_lock); 1579 } 1580 1581 /* ...and flush everything in the log out to disk. */ 1582 spin_lock(&journal->j_list_lock); 1583 while (!err && journal->j_checkpoint_transactions != NULL) { 1584 spin_unlock(&journal->j_list_lock); 1585 mutex_lock(&journal->j_checkpoint_mutex); 1586 err = jbd2_log_do_checkpoint(journal); 1587 mutex_unlock(&journal->j_checkpoint_mutex); 1588 spin_lock(&journal->j_list_lock); 1589 } 1590 spin_unlock(&journal->j_list_lock); 1591 1592 if (is_journal_aborted(journal)) 1593 return -EIO; 1594 1595 jbd2_cleanup_journal_tail(journal); 1596 1597 /* Finally, mark the journal as really needing no recovery. 1598 * This sets s_start==0 in the underlying superblock, which is 1599 * the magic code for a fully-recovered superblock. Any future 1600 * commits of data to the journal will restore the current 1601 * s_start value. */ 1602 write_lock(&journal->j_state_lock); 1603 old_tail = journal->j_tail; 1604 journal->j_tail = 0; 1605 write_unlock(&journal->j_state_lock); 1606 jbd2_journal_update_superblock(journal, 1); 1607 write_lock(&journal->j_state_lock); 1608 journal->j_tail = old_tail; 1609 1610 J_ASSERT(!journal->j_running_transaction); 1611 J_ASSERT(!journal->j_committing_transaction); 1612 J_ASSERT(!journal->j_checkpoint_transactions); 1613 J_ASSERT(journal->j_head == journal->j_tail); 1614 J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence); 1615 write_unlock(&journal->j_state_lock); 1616 return 0; 1617 } 1618 1619 /** 1620 * int jbd2_journal_wipe() - Wipe journal contents 1621 * @journal: Journal to act on. 1622 * @write: flag (see below) 1623 * 1624 * Wipe out all of the contents of a journal, safely. This will produce 1625 * a warning if the journal contains any valid recovery information. 1626 * Must be called between journal_init_*() and jbd2_journal_load(). 1627 * 1628 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise 1629 * we merely suppress recovery. 1630 */ 1631 1632 int jbd2_journal_wipe(journal_t *journal, int write) 1633 { 1634 int err = 0; 1635 1636 J_ASSERT (!(journal->j_flags & JBD2_LOADED)); 1637 1638 err = load_superblock(journal); 1639 if (err) 1640 return err; 1641 1642 if (!journal->j_tail) 1643 goto no_recovery; 1644 1645 printk (KERN_WARNING "JBD: %s recovery information on journal\n", 1646 write ? "Clearing" : "Ignoring"); 1647 1648 err = jbd2_journal_skip_recovery(journal); 1649 if (write) 1650 jbd2_journal_update_superblock(journal, 1); 1651 1652 no_recovery: 1653 return err; 1654 } 1655 1656 /* 1657 * Journal abort has very specific semantics, which we describe 1658 * for journal abort. 1659 * 1660 * Two internal functions, which provide abort to the jbd layer 1661 * itself are here. 1662 */ 1663 1664 /* 1665 * Quick version for internal journal use (doesn't lock the journal). 1666 * Aborts hard --- we mark the abort as occurred, but do _nothing_ else, 1667 * and don't attempt to make any other journal updates. 1668 */ 1669 void __jbd2_journal_abort_hard(journal_t *journal) 1670 { 1671 transaction_t *transaction; 1672 1673 if (journal->j_flags & JBD2_ABORT) 1674 return; 1675 1676 printk(KERN_ERR "Aborting journal on device %s.\n", 1677 journal->j_devname); 1678 1679 write_lock(&journal->j_state_lock); 1680 journal->j_flags |= JBD2_ABORT; 1681 transaction = journal->j_running_transaction; 1682 if (transaction) 1683 __jbd2_log_start_commit(journal, transaction->t_tid); 1684 write_unlock(&journal->j_state_lock); 1685 } 1686 1687 /* Soft abort: record the abort error status in the journal superblock, 1688 * but don't do any other IO. */ 1689 static void __journal_abort_soft (journal_t *journal, int errno) 1690 { 1691 if (journal->j_flags & JBD2_ABORT) 1692 return; 1693 1694 if (!journal->j_errno) 1695 journal->j_errno = errno; 1696 1697 __jbd2_journal_abort_hard(journal); 1698 1699 if (errno) 1700 jbd2_journal_update_superblock(journal, 1); 1701 } 1702 1703 /** 1704 * void jbd2_journal_abort () - Shutdown the journal immediately. 1705 * @journal: the journal to shutdown. 1706 * @errno: an error number to record in the journal indicating 1707 * the reason for the shutdown. 1708 * 1709 * Perform a complete, immediate shutdown of the ENTIRE 1710 * journal (not of a single transaction). This operation cannot be 1711 * undone without closing and reopening the journal. 1712 * 1713 * The jbd2_journal_abort function is intended to support higher level error 1714 * recovery mechanisms such as the ext2/ext3 remount-readonly error 1715 * mode. 1716 * 1717 * Journal abort has very specific semantics. Any existing dirty, 1718 * unjournaled buffers in the main filesystem will still be written to 1719 * disk by bdflush, but the journaling mechanism will be suspended 1720 * immediately and no further transaction commits will be honoured. 1721 * 1722 * Any dirty, journaled buffers will be written back to disk without 1723 * hitting the journal. Atomicity cannot be guaranteed on an aborted 1724 * filesystem, but we _do_ attempt to leave as much data as possible 1725 * behind for fsck to use for cleanup. 1726 * 1727 * Any attempt to get a new transaction handle on a journal which is in 1728 * ABORT state will just result in an -EROFS error return. A 1729 * jbd2_journal_stop on an existing handle will return -EIO if we have 1730 * entered abort state during the update. 1731 * 1732 * Recursive transactions are not disturbed by journal abort until the 1733 * final jbd2_journal_stop, which will receive the -EIO error. 1734 * 1735 * Finally, the jbd2_journal_abort call allows the caller to supply an errno 1736 * which will be recorded (if possible) in the journal superblock. This 1737 * allows a client to record failure conditions in the middle of a 1738 * transaction without having to complete the transaction to record the 1739 * failure to disk. ext3_error, for example, now uses this 1740 * functionality. 1741 * 1742 * Errors which originate from within the journaling layer will NOT 1743 * supply an errno; a null errno implies that absolutely no further 1744 * writes are done to the journal (unless there are any already in 1745 * progress). 1746 * 1747 */ 1748 1749 void jbd2_journal_abort(journal_t *journal, int errno) 1750 { 1751 __journal_abort_soft(journal, errno); 1752 } 1753 1754 /** 1755 * int jbd2_journal_errno () - returns the journal's error state. 1756 * @journal: journal to examine. 1757 * 1758 * This is the errno number set with jbd2_journal_abort(), the last 1759 * time the journal was mounted - if the journal was stopped 1760 * without calling abort this will be 0. 1761 * 1762 * If the journal has been aborted on this mount time -EROFS will 1763 * be returned. 1764 */ 1765 int jbd2_journal_errno(journal_t *journal) 1766 { 1767 int err; 1768 1769 read_lock(&journal->j_state_lock); 1770 if (journal->j_flags & JBD2_ABORT) 1771 err = -EROFS; 1772 else 1773 err = journal->j_errno; 1774 read_unlock(&journal->j_state_lock); 1775 return err; 1776 } 1777 1778 /** 1779 * int jbd2_journal_clear_err () - clears the journal's error state 1780 * @journal: journal to act on. 1781 * 1782 * An error must be cleared or acked to take a FS out of readonly 1783 * mode. 1784 */ 1785 int jbd2_journal_clear_err(journal_t *journal) 1786 { 1787 int err = 0; 1788 1789 write_lock(&journal->j_state_lock); 1790 if (journal->j_flags & JBD2_ABORT) 1791 err = -EROFS; 1792 else 1793 journal->j_errno = 0; 1794 write_unlock(&journal->j_state_lock); 1795 return err; 1796 } 1797 1798 /** 1799 * void jbd2_journal_ack_err() - Ack journal err. 1800 * @journal: journal to act on. 1801 * 1802 * An error must be cleared or acked to take a FS out of readonly 1803 * mode. 1804 */ 1805 void jbd2_journal_ack_err(journal_t *journal) 1806 { 1807 write_lock(&journal->j_state_lock); 1808 if (journal->j_errno) 1809 journal->j_flags |= JBD2_ACK_ERR; 1810 write_unlock(&journal->j_state_lock); 1811 } 1812 1813 int jbd2_journal_blocks_per_page(struct inode *inode) 1814 { 1815 return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits); 1816 } 1817 1818 /* 1819 * helper functions to deal with 32 or 64bit block numbers. 1820 */ 1821 size_t journal_tag_bytes(journal_t *journal) 1822 { 1823 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) 1824 return JBD2_TAG_SIZE64; 1825 else 1826 return JBD2_TAG_SIZE32; 1827 } 1828 1829 /* 1830 * JBD memory management 1831 * 1832 * These functions are used to allocate block-sized chunks of memory 1833 * used for making copies of buffer_head data. Very often it will be 1834 * page-sized chunks of data, but sometimes it will be in 1835 * sub-page-size chunks. (For example, 16k pages on Power systems 1836 * with a 4k block file system.) For blocks smaller than a page, we 1837 * use a SLAB allocator. There are slab caches for each block size, 1838 * which are allocated at mount time, if necessary, and we only free 1839 * (all of) the slab caches when/if the jbd2 module is unloaded. For 1840 * this reason we don't need to a mutex to protect access to 1841 * jbd2_slab[] allocating or releasing memory; only in 1842 * jbd2_journal_create_slab(). 1843 */ 1844 #define JBD2_MAX_SLABS 8 1845 static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS]; 1846 1847 static const char *jbd2_slab_names[JBD2_MAX_SLABS] = { 1848 "jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k", 1849 "jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k" 1850 }; 1851 1852 1853 static void jbd2_journal_destroy_slabs(void) 1854 { 1855 int i; 1856 1857 for (i = 0; i < JBD2_MAX_SLABS; i++) { 1858 if (jbd2_slab[i]) 1859 kmem_cache_destroy(jbd2_slab[i]); 1860 jbd2_slab[i] = NULL; 1861 } 1862 } 1863 1864 static int jbd2_journal_create_slab(size_t size) 1865 { 1866 static DEFINE_MUTEX(jbd2_slab_create_mutex); 1867 int i = order_base_2(size) - 10; 1868 size_t slab_size; 1869 1870 if (size == PAGE_SIZE) 1871 return 0; 1872 1873 if (i >= JBD2_MAX_SLABS) 1874 return -EINVAL; 1875 1876 if (unlikely(i < 0)) 1877 i = 0; 1878 mutex_lock(&jbd2_slab_create_mutex); 1879 if (jbd2_slab[i]) { 1880 mutex_unlock(&jbd2_slab_create_mutex); 1881 return 0; /* Already created */ 1882 } 1883 1884 slab_size = 1 << (i+10); 1885 jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size, 1886 slab_size, 0, NULL); 1887 mutex_unlock(&jbd2_slab_create_mutex); 1888 if (!jbd2_slab[i]) { 1889 printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n"); 1890 return -ENOMEM; 1891 } 1892 return 0; 1893 } 1894 1895 static struct kmem_cache *get_slab(size_t size) 1896 { 1897 int i = order_base_2(size) - 10; 1898 1899 BUG_ON(i >= JBD2_MAX_SLABS); 1900 if (unlikely(i < 0)) 1901 i = 0; 1902 BUG_ON(jbd2_slab[i] == NULL); 1903 return jbd2_slab[i]; 1904 } 1905 1906 void *jbd2_alloc(size_t size, gfp_t flags) 1907 { 1908 void *ptr; 1909 1910 BUG_ON(size & (size-1)); /* Must be a power of 2 */ 1911 1912 flags |= __GFP_REPEAT; 1913 if (size == PAGE_SIZE) 1914 ptr = (void *)__get_free_pages(flags, 0); 1915 else if (size > PAGE_SIZE) { 1916 int order = get_order(size); 1917 1918 if (order < 3) 1919 ptr = (void *)__get_free_pages(flags, order); 1920 else 1921 ptr = vmalloc(size); 1922 } else 1923 ptr = kmem_cache_alloc(get_slab(size), flags); 1924 1925 /* Check alignment; SLUB has gotten this wrong in the past, 1926 * and this can lead to user data corruption! */ 1927 BUG_ON(((unsigned long) ptr) & (size-1)); 1928 1929 return ptr; 1930 } 1931 1932 void jbd2_free(void *ptr, size_t size) 1933 { 1934 if (size == PAGE_SIZE) { 1935 free_pages((unsigned long)ptr, 0); 1936 return; 1937 } 1938 if (size > PAGE_SIZE) { 1939 int order = get_order(size); 1940 1941 if (order < 3) 1942 free_pages((unsigned long)ptr, order); 1943 else 1944 vfree(ptr); 1945 return; 1946 } 1947 kmem_cache_free(get_slab(size), ptr); 1948 }; 1949 1950 /* 1951 * Journal_head storage management 1952 */ 1953 static struct kmem_cache *jbd2_journal_head_cache; 1954 #ifdef CONFIG_JBD2_DEBUG 1955 static atomic_t nr_journal_heads = ATOMIC_INIT(0); 1956 #endif 1957 1958 static int journal_init_jbd2_journal_head_cache(void) 1959 { 1960 int retval; 1961 1962 J_ASSERT(jbd2_journal_head_cache == NULL); 1963 jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head", 1964 sizeof(struct journal_head), 1965 0, /* offset */ 1966 SLAB_TEMPORARY, /* flags */ 1967 NULL); /* ctor */ 1968 retval = 0; 1969 if (!jbd2_journal_head_cache) { 1970 retval = -ENOMEM; 1971 printk(KERN_EMERG "JBD: no memory for journal_head cache\n"); 1972 } 1973 return retval; 1974 } 1975 1976 static void jbd2_journal_destroy_jbd2_journal_head_cache(void) 1977 { 1978 if (jbd2_journal_head_cache) { 1979 kmem_cache_destroy(jbd2_journal_head_cache); 1980 jbd2_journal_head_cache = NULL; 1981 } 1982 } 1983 1984 /* 1985 * journal_head splicing and dicing 1986 */ 1987 static struct journal_head *journal_alloc_journal_head(void) 1988 { 1989 struct journal_head *ret; 1990 1991 #ifdef CONFIG_JBD2_DEBUG 1992 atomic_inc(&nr_journal_heads); 1993 #endif 1994 ret = kmem_cache_alloc(jbd2_journal_head_cache, GFP_NOFS); 1995 if (!ret) { 1996 jbd_debug(1, "out of memory for journal_head\n"); 1997 pr_notice_ratelimited("ENOMEM in %s, retrying.\n", __func__); 1998 while (!ret) { 1999 yield(); 2000 ret = kmem_cache_alloc(jbd2_journal_head_cache, GFP_NOFS); 2001 } 2002 } 2003 return ret; 2004 } 2005 2006 static void journal_free_journal_head(struct journal_head *jh) 2007 { 2008 #ifdef CONFIG_JBD2_DEBUG 2009 atomic_dec(&nr_journal_heads); 2010 memset(jh, JBD2_POISON_FREE, sizeof(*jh)); 2011 #endif 2012 kmem_cache_free(jbd2_journal_head_cache, jh); 2013 } 2014 2015 /* 2016 * A journal_head is attached to a buffer_head whenever JBD has an 2017 * interest in the buffer. 2018 * 2019 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit 2020 * is set. This bit is tested in core kernel code where we need to take 2021 * JBD-specific actions. Testing the zeroness of ->b_private is not reliable 2022 * there. 2023 * 2024 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one. 2025 * 2026 * When a buffer has its BH_JBD bit set it is immune from being released by 2027 * core kernel code, mainly via ->b_count. 2028 * 2029 * A journal_head may be detached from its buffer_head when the journal_head's 2030 * b_transaction, b_cp_transaction and b_next_transaction pointers are NULL. 2031 * Various places in JBD call jbd2_journal_remove_journal_head() to indicate that the 2032 * journal_head can be dropped if needed. 2033 * 2034 * Various places in the kernel want to attach a journal_head to a buffer_head 2035 * _before_ attaching the journal_head to a transaction. To protect the 2036 * journal_head in this situation, jbd2_journal_add_journal_head elevates the 2037 * journal_head's b_jcount refcount by one. The caller must call 2038 * jbd2_journal_put_journal_head() to undo this. 2039 * 2040 * So the typical usage would be: 2041 * 2042 * (Attach a journal_head if needed. Increments b_jcount) 2043 * struct journal_head *jh = jbd2_journal_add_journal_head(bh); 2044 * ... 2045 * jh->b_transaction = xxx; 2046 * jbd2_journal_put_journal_head(jh); 2047 * 2048 * Now, the journal_head's b_jcount is zero, but it is safe from being released 2049 * because it has a non-zero b_transaction. 2050 */ 2051 2052 /* 2053 * Give a buffer_head a journal_head. 2054 * 2055 * Doesn't need the journal lock. 2056 * May sleep. 2057 */ 2058 struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh) 2059 { 2060 struct journal_head *jh; 2061 struct journal_head *new_jh = NULL; 2062 2063 repeat: 2064 if (!buffer_jbd(bh)) { 2065 new_jh = journal_alloc_journal_head(); 2066 memset(new_jh, 0, sizeof(*new_jh)); 2067 } 2068 2069 jbd_lock_bh_journal_head(bh); 2070 if (buffer_jbd(bh)) { 2071 jh = bh2jh(bh); 2072 } else { 2073 J_ASSERT_BH(bh, 2074 (atomic_read(&bh->b_count) > 0) || 2075 (bh->b_page && bh->b_page->mapping)); 2076 2077 if (!new_jh) { 2078 jbd_unlock_bh_journal_head(bh); 2079 goto repeat; 2080 } 2081 2082 jh = new_jh; 2083 new_jh = NULL; /* We consumed it */ 2084 set_buffer_jbd(bh); 2085 bh->b_private = jh; 2086 jh->b_bh = bh; 2087 get_bh(bh); 2088 BUFFER_TRACE(bh, "added journal_head"); 2089 } 2090 jh->b_jcount++; 2091 jbd_unlock_bh_journal_head(bh); 2092 if (new_jh) 2093 journal_free_journal_head(new_jh); 2094 return bh->b_private; 2095 } 2096 2097 /* 2098 * Grab a ref against this buffer_head's journal_head. If it ended up not 2099 * having a journal_head, return NULL 2100 */ 2101 struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh) 2102 { 2103 struct journal_head *jh = NULL; 2104 2105 jbd_lock_bh_journal_head(bh); 2106 if (buffer_jbd(bh)) { 2107 jh = bh2jh(bh); 2108 jh->b_jcount++; 2109 } 2110 jbd_unlock_bh_journal_head(bh); 2111 return jh; 2112 } 2113 2114 static void __journal_remove_journal_head(struct buffer_head *bh) 2115 { 2116 struct journal_head *jh = bh2jh(bh); 2117 2118 J_ASSERT_JH(jh, jh->b_jcount >= 0); 2119 2120 get_bh(bh); 2121 if (jh->b_jcount == 0) { 2122 if (jh->b_transaction == NULL && 2123 jh->b_next_transaction == NULL && 2124 jh->b_cp_transaction == NULL) { 2125 J_ASSERT_JH(jh, jh->b_jlist == BJ_None); 2126 J_ASSERT_BH(bh, buffer_jbd(bh)); 2127 J_ASSERT_BH(bh, jh2bh(jh) == bh); 2128 BUFFER_TRACE(bh, "remove journal_head"); 2129 if (jh->b_frozen_data) { 2130 printk(KERN_WARNING "%s: freeing " 2131 "b_frozen_data\n", 2132 __func__); 2133 jbd2_free(jh->b_frozen_data, bh->b_size); 2134 } 2135 if (jh->b_committed_data) { 2136 printk(KERN_WARNING "%s: freeing " 2137 "b_committed_data\n", 2138 __func__); 2139 jbd2_free(jh->b_committed_data, bh->b_size); 2140 } 2141 bh->b_private = NULL; 2142 jh->b_bh = NULL; /* debug, really */ 2143 clear_buffer_jbd(bh); 2144 __brelse(bh); 2145 journal_free_journal_head(jh); 2146 } else { 2147 BUFFER_TRACE(bh, "journal_head was locked"); 2148 } 2149 } 2150 } 2151 2152 /* 2153 * jbd2_journal_remove_journal_head(): if the buffer isn't attached to a transaction 2154 * and has a zero b_jcount then remove and release its journal_head. If we did 2155 * see that the buffer is not used by any transaction we also "logically" 2156 * decrement ->b_count. 2157 * 2158 * We in fact take an additional increment on ->b_count as a convenience, 2159 * because the caller usually wants to do additional things with the bh 2160 * after calling here. 2161 * The caller of jbd2_journal_remove_journal_head() *must* run __brelse(bh) at some 2162 * time. Once the caller has run __brelse(), the buffer is eligible for 2163 * reaping by try_to_free_buffers(). 2164 */ 2165 void jbd2_journal_remove_journal_head(struct buffer_head *bh) 2166 { 2167 jbd_lock_bh_journal_head(bh); 2168 __journal_remove_journal_head(bh); 2169 jbd_unlock_bh_journal_head(bh); 2170 } 2171 2172 /* 2173 * Drop a reference on the passed journal_head. If it fell to zero then try to 2174 * release the journal_head from the buffer_head. 2175 */ 2176 void jbd2_journal_put_journal_head(struct journal_head *jh) 2177 { 2178 struct buffer_head *bh = jh2bh(jh); 2179 2180 jbd_lock_bh_journal_head(bh); 2181 J_ASSERT_JH(jh, jh->b_jcount > 0); 2182 --jh->b_jcount; 2183 if (!jh->b_jcount && !jh->b_transaction) { 2184 __journal_remove_journal_head(bh); 2185 __brelse(bh); 2186 } 2187 jbd_unlock_bh_journal_head(bh); 2188 } 2189 2190 /* 2191 * Initialize jbd inode head 2192 */ 2193 void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode) 2194 { 2195 jinode->i_transaction = NULL; 2196 jinode->i_next_transaction = NULL; 2197 jinode->i_vfs_inode = inode; 2198 jinode->i_flags = 0; 2199 INIT_LIST_HEAD(&jinode->i_list); 2200 } 2201 2202 /* 2203 * Function to be called before we start removing inode from memory (i.e., 2204 * clear_inode() is a fine place to be called from). It removes inode from 2205 * transaction's lists. 2206 */ 2207 void jbd2_journal_release_jbd_inode(journal_t *journal, 2208 struct jbd2_inode *jinode) 2209 { 2210 if (!journal) 2211 return; 2212 restart: 2213 spin_lock(&journal->j_list_lock); 2214 /* Is commit writing out inode - we have to wait */ 2215 if (test_bit(__JI_COMMIT_RUNNING, &jinode->i_flags)) { 2216 wait_queue_head_t *wq; 2217 DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING); 2218 wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING); 2219 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE); 2220 spin_unlock(&journal->j_list_lock); 2221 schedule(); 2222 finish_wait(wq, &wait.wait); 2223 goto restart; 2224 } 2225 2226 if (jinode->i_transaction) { 2227 list_del(&jinode->i_list); 2228 jinode->i_transaction = NULL; 2229 } 2230 spin_unlock(&journal->j_list_lock); 2231 } 2232 2233 /* 2234 * debugfs tunables 2235 */ 2236 #ifdef CONFIG_JBD2_DEBUG 2237 u8 jbd2_journal_enable_debug __read_mostly; 2238 EXPORT_SYMBOL(jbd2_journal_enable_debug); 2239 2240 #define JBD2_DEBUG_NAME "jbd2-debug" 2241 2242 static struct dentry *jbd2_debugfs_dir; 2243 static struct dentry *jbd2_debug; 2244 2245 static void __init jbd2_create_debugfs_entry(void) 2246 { 2247 jbd2_debugfs_dir = debugfs_create_dir("jbd2", NULL); 2248 if (jbd2_debugfs_dir) 2249 jbd2_debug = debugfs_create_u8(JBD2_DEBUG_NAME, 2250 S_IRUGO | S_IWUSR, 2251 jbd2_debugfs_dir, 2252 &jbd2_journal_enable_debug); 2253 } 2254 2255 static void __exit jbd2_remove_debugfs_entry(void) 2256 { 2257 debugfs_remove(jbd2_debug); 2258 debugfs_remove(jbd2_debugfs_dir); 2259 } 2260 2261 #else 2262 2263 static void __init jbd2_create_debugfs_entry(void) 2264 { 2265 } 2266 2267 static void __exit jbd2_remove_debugfs_entry(void) 2268 { 2269 } 2270 2271 #endif 2272 2273 #ifdef CONFIG_PROC_FS 2274 2275 #define JBD2_STATS_PROC_NAME "fs/jbd2" 2276 2277 static void __init jbd2_create_jbd_stats_proc_entry(void) 2278 { 2279 proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL); 2280 } 2281 2282 static void __exit jbd2_remove_jbd_stats_proc_entry(void) 2283 { 2284 if (proc_jbd2_stats) 2285 remove_proc_entry(JBD2_STATS_PROC_NAME, NULL); 2286 } 2287 2288 #else 2289 2290 #define jbd2_create_jbd_stats_proc_entry() do {} while (0) 2291 #define jbd2_remove_jbd_stats_proc_entry() do {} while (0) 2292 2293 #endif 2294 2295 struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache; 2296 2297 static int __init journal_init_handle_cache(void) 2298 { 2299 jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY); 2300 if (jbd2_handle_cache == NULL) { 2301 printk(KERN_EMERG "JBD2: failed to create handle cache\n"); 2302 return -ENOMEM; 2303 } 2304 jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0); 2305 if (jbd2_inode_cache == NULL) { 2306 printk(KERN_EMERG "JBD2: failed to create inode cache\n"); 2307 kmem_cache_destroy(jbd2_handle_cache); 2308 return -ENOMEM; 2309 } 2310 return 0; 2311 } 2312 2313 static void jbd2_journal_destroy_handle_cache(void) 2314 { 2315 if (jbd2_handle_cache) 2316 kmem_cache_destroy(jbd2_handle_cache); 2317 if (jbd2_inode_cache) 2318 kmem_cache_destroy(jbd2_inode_cache); 2319 2320 } 2321 2322 /* 2323 * Module startup and shutdown 2324 */ 2325 2326 static int __init journal_init_caches(void) 2327 { 2328 int ret; 2329 2330 ret = jbd2_journal_init_revoke_caches(); 2331 if (ret == 0) 2332 ret = journal_init_jbd2_journal_head_cache(); 2333 if (ret == 0) 2334 ret = journal_init_handle_cache(); 2335 return ret; 2336 } 2337 2338 static void jbd2_journal_destroy_caches(void) 2339 { 2340 jbd2_journal_destroy_revoke_caches(); 2341 jbd2_journal_destroy_jbd2_journal_head_cache(); 2342 jbd2_journal_destroy_handle_cache(); 2343 jbd2_journal_destroy_slabs(); 2344 } 2345 2346 static int __init journal_init(void) 2347 { 2348 int ret; 2349 2350 BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024); 2351 2352 ret = journal_init_caches(); 2353 if (ret == 0) { 2354 jbd2_create_debugfs_entry(); 2355 jbd2_create_jbd_stats_proc_entry(); 2356 } else { 2357 jbd2_journal_destroy_caches(); 2358 } 2359 return ret; 2360 } 2361 2362 static void __exit journal_exit(void) 2363 { 2364 #ifdef CONFIG_JBD2_DEBUG 2365 int n = atomic_read(&nr_journal_heads); 2366 if (n) 2367 printk(KERN_EMERG "JBD: leaked %d journal_heads!\n", n); 2368 #endif 2369 jbd2_remove_debugfs_entry(); 2370 jbd2_remove_jbd_stats_proc_entry(); 2371 jbd2_journal_destroy_caches(); 2372 } 2373 2374 /* 2375 * jbd2_dev_to_name is a utility function used by the jbd2 and ext4 2376 * tracing infrastructure to map a dev_t to a device name. 2377 * 2378 * The caller should use rcu_read_lock() in order to make sure the 2379 * device name stays valid until its done with it. We use 2380 * rcu_read_lock() as well to make sure we're safe in case the caller 2381 * gets sloppy, and because rcu_read_lock() is cheap and can be safely 2382 * nested. 2383 */ 2384 struct devname_cache { 2385 struct rcu_head rcu; 2386 dev_t device; 2387 char devname[BDEVNAME_SIZE]; 2388 }; 2389 #define CACHE_SIZE_BITS 6 2390 static struct devname_cache *devcache[1 << CACHE_SIZE_BITS]; 2391 static DEFINE_SPINLOCK(devname_cache_lock); 2392 2393 static void free_devcache(struct rcu_head *rcu) 2394 { 2395 kfree(rcu); 2396 } 2397 2398 const char *jbd2_dev_to_name(dev_t device) 2399 { 2400 int i = hash_32(device, CACHE_SIZE_BITS); 2401 char *ret; 2402 struct block_device *bd; 2403 static struct devname_cache *new_dev; 2404 2405 rcu_read_lock(); 2406 if (devcache[i] && devcache[i]->device == device) { 2407 ret = devcache[i]->devname; 2408 rcu_read_unlock(); 2409 return ret; 2410 } 2411 rcu_read_unlock(); 2412 2413 new_dev = kmalloc(sizeof(struct devname_cache), GFP_KERNEL); 2414 if (!new_dev) 2415 return "NODEV-ALLOCFAILURE"; /* Something non-NULL */ 2416 spin_lock(&devname_cache_lock); 2417 if (devcache[i]) { 2418 if (devcache[i]->device == device) { 2419 kfree(new_dev); 2420 ret = devcache[i]->devname; 2421 spin_unlock(&devname_cache_lock); 2422 return ret; 2423 } 2424 call_rcu(&devcache[i]->rcu, free_devcache); 2425 } 2426 devcache[i] = new_dev; 2427 devcache[i]->device = device; 2428 bd = bdget(device); 2429 if (bd) { 2430 bdevname(bd, devcache[i]->devname); 2431 bdput(bd); 2432 } else 2433 __bdevname(device, devcache[i]->devname); 2434 ret = devcache[i]->devname; 2435 spin_unlock(&devname_cache_lock); 2436 return ret; 2437 } 2438 EXPORT_SYMBOL(jbd2_dev_to_name); 2439 2440 MODULE_LICENSE("GPL"); 2441 module_init(journal_init); 2442 module_exit(journal_exit); 2443 2444