fs/jbd2/journal.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * linux/fs/jbd2/journal.c
   4  *
   5  * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
   6  *
   7  * Copyright 1998 Red Hat corp --- All Rights Reserved
   8  *
   9  * Generic filesystem journal-writing code; part of the ext2fs
  10  * journaling system.
  11  *
  12  * This file manages journals: areas of disk reserved for logging
  13  * transactional updates.  This includes the kernel journaling thread
  14  * which is responsible for scheduling updates to the log.
  15  *
  16  * We do not actually manage the physical storage of the journal in this
  17  * file: that is left to a per-journal policy function, which allows us
  18  * to store the journal within a filesystem-specified area for ext2
  19  * journaling (ext2 can use a reserved inode for storing the log).
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/time.h>
  24 #include <linux/fs.h>
  25 #include <linux/jbd2.h>
  26 #include <linux/errno.h>
  27 #include <linux/slab.h>
  28 #include <linux/init.h>
  29 #include <linux/mm.h>
  30 #include <linux/freezer.h>
  31 #include <linux/pagemap.h>
  32 #include <linux/kthread.h>
  33 #include <linux/poison.h>
  34 #include <linux/proc_fs.h>
  35 #include <linux/seq_file.h>
  36 #include <linux/math64.h>
  37 #include <linux/hash.h>
  38 #include <linux/log2.h>
  39 #include <linux/vmalloc.h>
  40 #include <linux/backing-dev.h>
  41 #include <linux/bitops.h>
  42 #include <linux/ratelimit.h>
  43 #include <linux/sched/mm.h>
  44
  45 #define CREATE_TRACE_POINTS
  46 #include <trace/events/jbd2.h>
  47
  48 #include <linux/uaccess.h>
  49 #include <asm/page.h>
  50
  51 #ifdef CONFIG_JBD2_DEBUG
  52 ushort jbd2_journal_enable_debug __read_mostly;
  53 EXPORT_SYMBOL(jbd2_journal_enable_debug);
  54
  55 module_param_named(jbd2_debug, jbd2_journal_enable_debug, ushort, 0644);
  56 MODULE_PARM_DESC(jbd2_debug, "Debugging level for jbd2");
  57 #endif
  58
  59 EXPORT_SYMBOL(jbd2_journal_extend);
  60 EXPORT_SYMBOL(jbd2_journal_stop);
  61 EXPORT_SYMBOL(jbd2_journal_lock_updates);
  62 EXPORT_SYMBOL(jbd2_journal_unlock_updates);
  63 EXPORT_SYMBOL(jbd2_journal_get_write_access);
  64 EXPORT_SYMBOL(jbd2_journal_get_create_access);
  65 EXPORT_SYMBOL(jbd2_journal_get_undo_access);
  66 EXPORT_SYMBOL(jbd2_journal_set_triggers);
  67 EXPORT_SYMBOL(jbd2_journal_dirty_metadata);
  68 EXPORT_SYMBOL(jbd2_journal_forget);
  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_check_used_features);
  75 EXPORT_SYMBOL(jbd2_journal_check_available_features);
  76 EXPORT_SYMBOL(jbd2_journal_set_features);
  77 EXPORT_SYMBOL(jbd2_journal_load);
  78 EXPORT_SYMBOL(jbd2_journal_destroy);
  79 EXPORT_SYMBOL(jbd2_journal_abort);
  80 EXPORT_SYMBOL(jbd2_journal_errno);
  81 EXPORT_SYMBOL(jbd2_journal_ack_err);
  82 EXPORT_SYMBOL(jbd2_journal_clear_err);
  83 EXPORT_SYMBOL(jbd2_log_wait_commit);
  84 EXPORT_SYMBOL(jbd2_log_start_commit);
  85 EXPORT_SYMBOL(jbd2_journal_start_commit);
  86 EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
  87 EXPORT_SYMBOL(jbd2_journal_wipe);
  88 EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
  89 EXPORT_SYMBOL(jbd2_journal_invalidate_folio);
  90 EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
  91 EXPORT_SYMBOL(jbd2_journal_force_commit);
  92 EXPORT_SYMBOL(jbd2_journal_inode_ranged_write);
  93 EXPORT_SYMBOL(jbd2_journal_inode_ranged_wait);
  94 EXPORT_SYMBOL(jbd2_journal_submit_inode_data_buffers);
  95 EXPORT_SYMBOL(jbd2_journal_finish_inode_data_buffers);
  96 EXPORT_SYMBOL(jbd2_journal_init_jbd_inode);
  97 EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
  98 EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
  99 EXPORT_SYMBOL(jbd2_inode_cache);
 100
 101 static int jbd2_journal_create_slab(size_t slab_size);
 102
 103 #ifdef CONFIG_JBD2_DEBUG
 104 void __jbd2_debug(int level, const char *file, const char *func,
 105                   unsigned int line, const char *fmt, ...)
 106 {
 107         struct va_format vaf;
 108         va_list args;
 109
 110         if (level > jbd2_journal_enable_debug)
 111                 return;
 112         va_start(args, fmt);
 113         vaf.fmt = fmt;
 114         vaf.va = &args;
 115         printk(KERN_DEBUG "%s: (%s, %u): %pV", file, func, line, &vaf);
 116         va_end(args);
 117 }
 118 EXPORT_SYMBOL(__jbd2_debug);
 119 #endif
 120
 121 /* Checksumming functions */
 122 static int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb)
 123 {
 124         if (!jbd2_journal_has_csum_v2or3_feature(j))
 125                 return 1;
 126
 127         return sb->s_checksum_type == JBD2_CRC32C_CHKSUM;
 128 }
 129
 130 static __be32 jbd2_superblock_csum(journal_t *j, journal_superblock_t *sb)
 131 {
 132         __u32 csum;
 133         __be32 old_csum;
 134
 135         old_csum = sb->s_checksum;
 136         sb->s_checksum = 0;
 137         csum = jbd2_chksum(j, ~0, (char *)sb, sizeof(journal_superblock_t));
 138         sb->s_checksum = old_csum;
 139
 140         return cpu_to_be32(csum);
 141 }
 142
 143 /*
 144  * Helper function used to manage commit timeouts
 145  */
 146
 147 static void commit_timeout(struct timer_list *t)
 148 {
 149         journal_t *journal = from_timer(journal, t, j_commit_timer);
 150
 151         wake_up_process(journal->j_task);
 152 }
 153
 154 /*
 155  * kjournald2: The main thread function used to manage a logging device
 156  * journal.
 157  *
 158  * This kernel thread is responsible for two things:
 159  *
 160  * 1) COMMIT:  Every so often we need to commit the current state of the
 161  *    filesystem to disk.  The journal thread is responsible for writing
 162  *    all of the metadata buffers to disk. If a fast commit is ongoing
 163  *    journal thread waits until it's done and then continues from
 164  *    there on.
 165  *
 166  * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
 167  *    of the data in that part of the log has been rewritten elsewhere on
 168  *    the disk.  Flushing these old buffers to reclaim space in the log is
 169  *    known as checkpointing, and this thread is responsible for that job.
 170  */
 171
 172 static int kjournald2(void *arg)
 173 {
 174         journal_t *journal = arg;
 175         transaction_t *transaction;
 176
 177         /*
 178          * Set up an interval timer which can be used to trigger a commit wakeup
 179          * after the commit interval expires
 180          */
 181         timer_setup(&journal->j_commit_timer, commit_timeout, 0);
 182
 183         set_freezable();
 184
 185         /* Record that the journal thread is running */
 186         journal->j_task = current;
 187         wake_up(&journal->j_wait_done_commit);
 188
 189         /*
 190          * Make sure that no allocations from this kernel thread will ever
 191          * recurse to the fs layer because we are responsible for the
 192          * transaction commit and any fs involvement might get stuck waiting for
 193          * the trasn. commit.
 194          */
 195         memalloc_nofs_save();
 196
 197         /*
 198          * And now, wait forever for commit wakeup events.
 199          */
 200         write_lock(&journal->j_state_lock);
 201
 202 loop:
 203         if (journal->j_flags & JBD2_UNMOUNT)
 204                 goto end_loop;
 205
 206         jbd_debug(1, "commit_sequence=%u, commit_request=%u\n",
 207                 journal->j_commit_sequence, journal->j_commit_request);
 208
 209         if (journal->j_commit_sequence != journal->j_commit_request) {
 210                 jbd_debug(1, "OK, requests differ\n");
 211                 write_unlock(&journal->j_state_lock);
 212                 del_timer_sync(&journal->j_commit_timer);
 213                 jbd2_journal_commit_transaction(journal);
 214                 write_lock(&journal->j_state_lock);
 215                 goto loop;
 216         }
 217
 218         wake_up(&journal->j_wait_done_commit);
 219         if (freezing(current)) {
 220                 /*
 221                  * The simpler the better. Flushing journal isn't a
 222                  * good idea, because that depends on threads that may
 223                  * be already stopped.
 224                  */
 225                 jbd_debug(1, "Now suspending kjournald2\n");
 226                 write_unlock(&journal->j_state_lock);
 227                 try_to_freeze();
 228                 write_lock(&journal->j_state_lock);
 229         } else {
 230                 /*
 231                  * We assume on resume that commits are already there,
 232                  * so we don't sleep
 233                  */
 234                 DEFINE_WAIT(wait);
 235                 int should_sleep = 1;
 236
 237                 prepare_to_wait(&journal->j_wait_commit, &wait,
 238                                 TASK_INTERRUPTIBLE);
 239                 if (journal->j_commit_sequence != journal->j_commit_request)
 240                         should_sleep = 0;
 241                 transaction = journal->j_running_transaction;
 242                 if (transaction && time_after_eq(jiffies,
 243                                                 transaction->t_expires))
 244                         should_sleep = 0;
 245                 if (journal->j_flags & JBD2_UNMOUNT)
 246                         should_sleep = 0;
 247                 if (should_sleep) {
 248                         write_unlock(&journal->j_state_lock);
 249                         schedule();
 250                         write_lock(&journal->j_state_lock);
 251                 }
 252                 finish_wait(&journal->j_wait_commit, &wait);
 253         }
 254
 255         jbd_debug(1, "kjournald2 wakes\n");
 256
 257         /*
 258          * Were we woken up by a commit wakeup event?
 259          */
 260         transaction = journal->j_running_transaction;
 261         if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
 262                 journal->j_commit_request = transaction->t_tid;
 263                 jbd_debug(1, "woke because of timeout\n");
 264         }
 265         goto loop;
 266
 267 end_loop:
 268         del_timer_sync(&journal->j_commit_timer);
 269         journal->j_task = NULL;
 270         wake_up(&journal->j_wait_done_commit);
 271         jbd_debug(1, "Journal thread exiting.\n");
 272         write_unlock(&journal->j_state_lock);
 273         return 0;
 274 }
 275
 276 static int jbd2_journal_start_thread(journal_t *journal)
 277 {
 278         struct task_struct *t;
 279
 280         t = kthread_run(kjournald2, journal, "jbd2/%s",
 281                         journal->j_devname);
 282         if (IS_ERR(t))
 283                 return PTR_ERR(t);
 284
 285         wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
 286         return 0;
 287 }
 288
 289 static void journal_kill_thread(journal_t *journal)
 290 {
 291         write_lock(&journal->j_state_lock);
 292         journal->j_flags |= JBD2_UNMOUNT;
 293
 294         while (journal->j_task) {
 295                 write_unlock(&journal->j_state_lock);
 296                 wake_up(&journal->j_wait_commit);
 297                 wait_event(journal->j_wait_done_commit, journal->j_task == NULL);
 298                 write_lock(&journal->j_state_lock);
 299         }
 300         write_unlock(&journal->j_state_lock);
 301 }
 302
 303 /*
 304  * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
 305  *
 306  * Writes a metadata buffer to a given disk block.  The actual IO is not
 307  * performed but a new buffer_head is constructed which labels the data
 308  * to be written with the correct destination disk block.
 309  *
 310  * Any magic-number escaping which needs to be done will cause a
 311  * copy-out here.  If the buffer happens to start with the
 312  * JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the
 313  * magic number is only written to the log for descripter blocks.  In
 314  * this case, we copy the data and replace the first word with 0, and we
 315  * return a result code which indicates that this buffer needs to be
 316  * marked as an escaped buffer in the corresponding log descriptor
 317  * block.  The missing word can then be restored when the block is read
 318  * during recovery.
 319  *
 320  * If the source buffer has already been modified by a new transaction
 321  * since we took the last commit snapshot, we use the frozen copy of
 322  * that data for IO. If we end up using the existing buffer_head's data
 323  * for the write, then we have to make sure nobody modifies it while the
 324  * IO is in progress. do_get_write_access() handles this.
 325  *
 326  * The function returns a pointer to the buffer_head to be used for IO.
 327  *
 328  *
 329  * Return value:
 330  *  <0: Error
 331  * >=0: Finished OK
 332  *
 333  * On success:
 334  * Bit 0 set == escape performed on the data
 335  * Bit 1 set == buffer copy-out performed (kfree the data after IO)
 336  */
 337
 338 int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
 339                                   struct journal_head  *jh_in,
 340                                   struct buffer_head **bh_out,
 341                                   sector_t blocknr)
 342 {
 343         int need_copy_out = 0;
 344         int done_copy_out = 0;
 345         int do_escape = 0;
 346         char *mapped_data;
 347         struct buffer_head *new_bh;
 348         struct page *new_page;
 349         unsigned int new_offset;
 350         struct buffer_head *bh_in = jh2bh(jh_in);
 351         journal_t *journal = transaction->t_journal;
 352
 353         /*
 354          * The buffer really shouldn't be locked: only the current committing
 355          * transaction is allowed to write it, so nobody else is allowed
 356          * to do any IO.
 357          *
 358          * akpm: except if we're journalling data, and write() output is
 359          * also part of a shared mapping, and another thread has
 360          * decided to launch a writepage() against this buffer.
 361          */
 362         J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
 363
 364         new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
 365
 366         /* keep subsequent assertions sane */
 367         atomic_set(&new_bh->b_count, 1);
 368
 369         spin_lock(&jh_in->b_state_lock);
 370 repeat:
 371         /*
 372          * If a new transaction has already done a buffer copy-out, then
 373          * we use that version of the data for the commit.
 374          */
 375         if (jh_in->b_frozen_data) {
 376                 done_copy_out = 1;
 377                 new_page = virt_to_page(jh_in->b_frozen_data);
 378                 new_offset = offset_in_page(jh_in->b_frozen_data);
 379         } else {
 380                 new_page = jh2bh(jh_in)->b_page;
 381                 new_offset = offset_in_page(jh2bh(jh_in)->b_data);
 382         }
 383
 384         mapped_data = kmap_atomic(new_page);
 385         /*
 386          * Fire data frozen trigger if data already wasn't frozen.  Do this
 387          * before checking for escaping, as the trigger may modify the magic
 388          * offset.  If a copy-out happens afterwards, it will have the correct
 389          * data in the buffer.
 390          */
 391         if (!done_copy_out)
 392                 jbd2_buffer_frozen_trigger(jh_in, mapped_data + new_offset,
 393                                            jh_in->b_triggers);
 394
 395         /*
 396          * Check for escaping
 397          */
 398         if (*((__be32 *)(mapped_data + new_offset)) ==
 399                                 cpu_to_be32(JBD2_MAGIC_NUMBER)) {
 400                 need_copy_out = 1;
 401                 do_escape = 1;
 402         }
 403         kunmap_atomic(mapped_data);
 404
 405         /*
 406          * Do we need to do a data copy?
 407          */
 408         if (need_copy_out && !done_copy_out) {
 409                 char *tmp;
 410
 411                 spin_unlock(&jh_in->b_state_lock);
 412                 tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS);
 413                 if (!tmp) {
 414                         brelse(new_bh);
 415                         return -ENOMEM;
 416                 }
 417                 spin_lock(&jh_in->b_state_lock);
 418                 if (jh_in->b_frozen_data) {
 419                         jbd2_free(tmp, bh_in->b_size);
 420                         goto repeat;
 421                 }
 422
 423                 jh_in->b_frozen_data = tmp;
 424                 mapped_data = kmap_atomic(new_page);
 425                 memcpy(tmp, mapped_data + new_offset, bh_in->b_size);
 426                 kunmap_atomic(mapped_data);
 427
 428                 new_page = virt_to_page(tmp);
 429                 new_offset = offset_in_page(tmp);
 430                 done_copy_out = 1;
 431
 432                 /*
 433                  * This isn't strictly necessary, as we're using frozen
 434                  * data for the escaping, but it keeps consistency with
 435                  * b_frozen_data usage.
 436                  */
 437                 jh_in->b_frozen_triggers = jh_in->b_triggers;
 438         }
 439
 440         /*
 441          * Did we need to do an escaping?  Now we've done all the
 442          * copying, we can finally do so.
 443          */
 444         if (do_escape) {
 445                 mapped_data = kmap_atomic(new_page);
 446                 *((unsigned int *)(mapped_data + new_offset)) = 0;
 447                 kunmap_atomic(mapped_data);
 448         }
 449
 450         set_bh_page(new_bh, new_page, new_offset);
 451         new_bh->b_size = bh_in->b_size;
 452         new_bh->b_bdev = journal->j_dev;
 453         new_bh->b_blocknr = blocknr;
 454         new_bh->b_private = bh_in;
 455         set_buffer_mapped(new_bh);
 456         set_buffer_dirty(new_bh);
 457
 458         *bh_out = new_bh;
 459
 460         /*
 461          * The to-be-written buffer needs to get moved to the io queue,
 462          * and the original buffer whose contents we are shadowing or
 463          * copying is moved to the transaction's shadow queue.
 464          */
 465         JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
 466         spin_lock(&journal->j_list_lock);
 467         __jbd2_journal_file_buffer(jh_in, transaction, BJ_Shadow);
 468         spin_unlock(&journal->j_list_lock);
 469         set_buffer_shadow(bh_in);
 470         spin_unlock(&jh_in->b_state_lock);
 471
 472         return do_escape | (done_copy_out << 1);
 473 }
 474
 475 /*
 476  * Allocation code for the journal file.  Manage the space left in the
 477  * journal, so that we can begin checkpointing when appropriate.
 478  */
 479
 480 /*
 481  * Called with j_state_lock locked for writing.
 482  * Returns true if a transaction commit was started.
 483  */
 484 int __jbd2_log_start_commit(journal_t *journal, tid_t target)
 485 {
 486         /* Return if the txn has already requested to be committed */
 487         if (journal->j_commit_request == target)
 488                 return 0;
 489
 490         /*
 491          * The only transaction we can possibly wait upon is the
 492          * currently running transaction (if it exists).  Otherwise,
 493          * the target tid must be an old one.
 494          */
 495         if (journal->j_running_transaction &&
 496             journal->j_running_transaction->t_tid == target) {
 497                 /*
 498                  * We want a new commit: OK, mark the request and wakeup the
 499                  * commit thread.  We do _not_ do the commit ourselves.
 500                  */
 501
 502                 journal->j_commit_request = target;
 503                 jbd_debug(1, "JBD2: requesting commit %u/%u\n",
 504                           journal->j_commit_request,
 505                           journal->j_commit_sequence);
 506                 journal->j_running_transaction->t_requested = jiffies;
 507                 wake_up(&journal->j_wait_commit);
 508                 return 1;
 509         } else if (!tid_geq(journal->j_commit_request, target))
 510                 /* This should never happen, but if it does, preserve
 511                    the evidence before kjournald goes into a loop and
 512                    increments j_commit_sequence beyond all recognition. */
 513                 WARN_ONCE(1, "JBD2: bad log_start_commit: %u %u %u %u\n",
 514                           journal->j_commit_request,
 515                           journal->j_commit_sequence,
 516                           target, journal->j_running_transaction ?
 517                           journal->j_running_transaction->t_tid : 0);
 518         return 0;
 519 }
 520
 521 int jbd2_log_start_commit(journal_t *journal, tid_t tid)
 522 {
 523         int ret;
 524
 525         write_lock(&journal->j_state_lock);
 526         ret = __jbd2_log_start_commit(journal, tid);
 527         write_unlock(&journal->j_state_lock);
 528         return ret;
 529 }
 530
 531 /*
 532  * Force and wait any uncommitted transactions.  We can only force the running
 533  * transaction if we don't have an active handle, otherwise, we will deadlock.
 534  * Returns: <0 in case of error,
 535  *           0 if nothing to commit,
 536  *           1 if transaction was successfully committed.
 537  */
 538 static int __jbd2_journal_force_commit(journal_t *journal)
 539 {
 540         transaction_t *transaction = NULL;
 541         tid_t tid;
 542         int need_to_start = 0, ret = 0;
 543
 544         read_lock(&journal->j_state_lock);
 545         if (journal->j_running_transaction && !current->journal_info) {
 546                 transaction = journal->j_running_transaction;
 547                 if (!tid_geq(journal->j_commit_request, transaction->t_tid))
 548                         need_to_start = 1;
 549         } else if (journal->j_committing_transaction)
 550                 transaction = journal->j_committing_transaction;
 551
 552         if (!transaction) {
 553                 /* Nothing to commit */
 554                 read_unlock(&journal->j_state_lock);
 555                 return 0;
 556         }
 557         tid = transaction->t_tid;
 558         read_unlock(&journal->j_state_lock);
 559         if (need_to_start)
 560                 jbd2_log_start_commit(journal, tid);
 561         ret = jbd2_log_wait_commit(journal, tid);
 562         if (!ret)
 563                 ret = 1;
 564
 565         return ret;
 566 }
 567
 568 /**
 569  * jbd2_journal_force_commit_nested - Force and wait upon a commit if the
 570  * calling process is not within transaction.
 571  *
 572  * @journal: journal to force
 573  * Returns true if progress was made.
 574  *
 575  * This is used for forcing out undo-protected data which contains
 576  * bitmaps, when the fs is running out of space.
 577  */
 578 int jbd2_journal_force_commit_nested(journal_t *journal)
 579 {
 580         int ret;
 581
 582         ret = __jbd2_journal_force_commit(journal);
 583         return ret > 0;
 584 }
 585
 586 /**
 587  * jbd2_journal_force_commit() - force any uncommitted transactions
 588  * @journal: journal to force
 589  *
 590  * Caller want unconditional commit. We can only force the running transaction
 591  * if we don't have an active handle, otherwise, we will deadlock.
 592  */
 593 int jbd2_journal_force_commit(journal_t *journal)
 594 {
 595         int ret;
 596
 597         J_ASSERT(!current->journal_info);
 598         ret = __jbd2_journal_force_commit(journal);
 599         if (ret > 0)
 600                 ret = 0;
 601         return ret;
 602 }
 603
 604 /*
 605  * Start a commit of the current running transaction (if any).  Returns true
 606  * if a transaction is going to be committed (or is currently already
 607  * committing), and fills its tid in at *ptid
 608  */
 609 int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid)
 610 {
 611         int ret = 0;
 612
 613         write_lock(&journal->j_state_lock);
 614         if (journal->j_running_transaction) {
 615                 tid_t tid = journal->j_running_transaction->t_tid;
 616
 617                 __jbd2_log_start_commit(journal, tid);
 618                 /* There's a running transaction and we've just made sure
 619                  * it's commit has been scheduled. */
 620                 if (ptid)
 621                         *ptid = tid;
 622                 ret = 1;
 623         } else if (journal->j_committing_transaction) {
 624                 /*
 625                  * If commit has been started, then we have to wait for
 626                  * completion of that transaction.
 627                  */
 628                 if (ptid)
 629                         *ptid = journal->j_committing_transaction->t_tid;
 630                 ret = 1;
 631         }
 632         write_unlock(&journal->j_state_lock);
 633         return ret;
 634 }
 635
 636 /*
 637  * Return 1 if a given transaction has not yet sent barrier request
 638  * connected with a transaction commit. If 0 is returned, transaction
 639  * may or may not have sent the barrier. Used to avoid sending barrier
 640  * twice in common cases.
 641  */
 642 int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid)
 643 {
 644         int ret = 0;
 645         transaction_t *commit_trans;
 646
 647         if (!(journal->j_flags & JBD2_BARRIER))
 648                 return 0;
 649         read_lock(&journal->j_state_lock);
 650         /* Transaction already committed? */
 651         if (tid_geq(journal->j_commit_sequence, tid))
 652                 goto out;
 653         commit_trans = journal->j_committing_transaction;
 654         if (!commit_trans || commit_trans->t_tid != tid) {
 655                 ret = 1;
 656                 goto out;
 657         }
 658         /*
 659          * Transaction is being committed and we already proceeded to
 660          * submitting a flush to fs partition?
 661          */
 662         if (journal->j_fs_dev != journal->j_dev) {
 663                 if (!commit_trans->t_need_data_flush ||
 664                     commit_trans->t_state >= T_COMMIT_DFLUSH)
 665                         goto out;
 666         } else {
 667                 if (commit_trans->t_state >= T_COMMIT_JFLUSH)
 668                         goto out;
 669         }
 670         ret = 1;
 671 out:
 672         read_unlock(&journal->j_state_lock);
 673         return ret;
 674 }
 675 EXPORT_SYMBOL(jbd2_trans_will_send_data_barrier);
 676
 677 /*
 678  * Wait for a specified commit to complete.
 679  * The caller may not hold the journal lock.
 680  */
 681 int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
 682 {
 683         int err = 0;
 684
 685         read_lock(&journal->j_state_lock);
 686 #ifdef CONFIG_PROVE_LOCKING
 687         /*
 688          * Some callers make sure transaction is already committing and in that
 689          * case we cannot block on open handles anymore. So don't warn in that
 690          * case.
 691          */
 692         if (tid_gt(tid, journal->j_commit_sequence) &&
 693             (!journal->j_committing_transaction ||
 694              journal->j_committing_transaction->t_tid != tid)) {
 695                 read_unlock(&journal->j_state_lock);
 696                 jbd2_might_wait_for_commit(journal);
 697                 read_lock(&journal->j_state_lock);
 698         }
 699 #endif
 700 #ifdef CONFIG_JBD2_DEBUG
 701         if (!tid_geq(journal->j_commit_request, tid)) {
 702                 printk(KERN_ERR
 703                        "%s: error: j_commit_request=%u, tid=%u\n",
 704                        __func__, journal->j_commit_request, tid);
 705         }
 706 #endif
 707         while (tid_gt(tid, journal->j_commit_sequence)) {
 708                 jbd_debug(1, "JBD2: want %u, j_commit_sequence=%u\n",
 709                                   tid, journal->j_commit_sequence);
 710                 read_unlock(&journal->j_state_lock);
 711                 wake_up(&journal->j_wait_commit);
 712                 wait_event(journal->j_wait_done_commit,
 713                                 !tid_gt(tid, journal->j_commit_sequence));
 714                 read_lock(&journal->j_state_lock);
 715         }
 716         read_unlock(&journal->j_state_lock);
 717
 718         if (unlikely(is_journal_aborted(journal)))
 719                 err = -EIO;
 720         return err;
 721 }
 722
 723 /*
 724  * Start a fast commit. If there's an ongoing fast or full commit wait for
 725  * it to complete. Returns 0 if a new fast commit was started. Returns -EALREADY
 726  * if a fast commit is not needed, either because there's an already a commit
 727  * going on or this tid has already been committed. Returns -EINVAL if no jbd2
 728  * commit has yet been performed.
 729  */
 730 int jbd2_fc_begin_commit(journal_t *journal, tid_t tid)
 731 {
 732         if (unlikely(is_journal_aborted(journal)))
 733                 return -EIO;
 734         /*
 735          * Fast commits only allowed if at least one full commit has
 736          * been processed.
 737          */
 738         if (!journal->j_stats.ts_tid)
 739                 return -EINVAL;
 740
 741         write_lock(&journal->j_state_lock);
 742         if (tid <= journal->j_commit_sequence) {
 743                 write_unlock(&journal->j_state_lock);
 744                 return -EALREADY;
 745         }
 746
 747         if (journal->j_flags & JBD2_FULL_COMMIT_ONGOING ||
 748             (journal->j_flags & JBD2_FAST_COMMIT_ONGOING)) {
 749                 DEFINE_WAIT(wait);
 750
 751                 prepare_to_wait(&journal->j_fc_wait, &wait,
 752                                 TASK_UNINTERRUPTIBLE);
 753                 write_unlock(&journal->j_state_lock);
 754                 schedule();
 755                 finish_wait(&journal->j_fc_wait, &wait);
 756                 return -EALREADY;
 757         }
 758         journal->j_flags |= JBD2_FAST_COMMIT_ONGOING;
 759         write_unlock(&journal->j_state_lock);
 760         jbd2_journal_lock_updates(journal);
 761
 762         return 0;
 763 }
 764 EXPORT_SYMBOL(jbd2_fc_begin_commit);
 765
 766 /*
 767  * Stop a fast commit. If fallback is set, this function starts commit of
 768  * TID tid before any other fast commit can start.
 769  */
 770 static int __jbd2_fc_end_commit(journal_t *journal, tid_t tid, bool fallback)
 771 {
 772         jbd2_journal_unlock_updates(journal);
 773         if (journal->j_fc_cleanup_callback)
 774                 journal->j_fc_cleanup_callback(journal, 0, tid);
 775         write_lock(&journal->j_state_lock);
 776         journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
 777         if (fallback)
 778                 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
 779         write_unlock(&journal->j_state_lock);
 780         wake_up(&journal->j_fc_wait);
 781         if (fallback)
 782                 return jbd2_complete_transaction(journal, tid);
 783         return 0;
 784 }
 785
 786 int jbd2_fc_end_commit(journal_t *journal)
 787 {
 788         return __jbd2_fc_end_commit(journal, 0, false);
 789 }
 790 EXPORT_SYMBOL(jbd2_fc_end_commit);
 791
 792 int jbd2_fc_end_commit_fallback(journal_t *journal)
 793 {
 794         tid_t tid;
 795
 796         read_lock(&journal->j_state_lock);
 797         tid = journal->j_running_transaction ?
 798                 journal->j_running_transaction->t_tid : 0;
 799         read_unlock(&journal->j_state_lock);
 800         return __jbd2_fc_end_commit(journal, tid, true);
 801 }
 802 EXPORT_SYMBOL(jbd2_fc_end_commit_fallback);
 803
 804 /* Return 1 when transaction with given tid has already committed. */
 805 int jbd2_transaction_committed(journal_t *journal, tid_t tid)
 806 {
 807         int ret = 1;
 808
 809         read_lock(&journal->j_state_lock);
 810         if (journal->j_running_transaction &&
 811             journal->j_running_transaction->t_tid == tid)
 812                 ret = 0;
 813         if (journal->j_committing_transaction &&
 814             journal->j_committing_transaction->t_tid == tid)
 815                 ret = 0;
 816         read_unlock(&journal->j_state_lock);
 817         return ret;
 818 }
 819 EXPORT_SYMBOL(jbd2_transaction_committed);
 820
 821 /*
 822  * When this function returns the transaction corresponding to tid
 823  * will be completed.  If the transaction has currently running, start
 824  * committing that transaction before waiting for it to complete.  If
 825  * the transaction id is stale, it is by definition already completed,
 826  * so just return SUCCESS.
 827  */
 828 int jbd2_complete_transaction(journal_t *journal, tid_t tid)
 829 {
 830         int     need_to_wait = 1;
 831
 832         read_lock(&journal->j_state_lock);
 833         if (journal->j_running_transaction &&
 834             journal->j_running_transaction->t_tid == tid) {
 835                 if (journal->j_commit_request != tid) {
 836                         /* transaction not yet started, so request it */
 837                         read_unlock(&journal->j_state_lock);
 838                         jbd2_log_start_commit(journal, tid);
 839                         goto wait_commit;
 840                 }
 841         } else if (!(journal->j_committing_transaction &&
 842                      journal->j_committing_transaction->t_tid == tid))
 843                 need_to_wait = 0;
 844         read_unlock(&journal->j_state_lock);
 845         if (!need_to_wait)
 846                 return 0;
 847 wait_commit:
 848         return jbd2_log_wait_commit(journal, tid);
 849 }
 850 EXPORT_SYMBOL(jbd2_complete_transaction);
 851
 852 /*
 853  * Log buffer allocation routines:
 854  */
 855
 856 int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
 857 {
 858         unsigned long blocknr;
 859
 860         write_lock(&journal->j_state_lock);
 861         J_ASSERT(journal->j_free > 1);
 862
 863         blocknr = journal->j_head;
 864         journal->j_head++;
 865         journal->j_free--;
 866         if (journal->j_head == journal->j_last)
 867                 journal->j_head = journal->j_first;
 868         write_unlock(&journal->j_state_lock);
 869         return jbd2_journal_bmap(journal, blocknr, retp);
 870 }
 871
 872 /* Map one fast commit buffer for use by the file system */
 873 int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out)
 874 {
 875         unsigned long long pblock;
 876         unsigned long blocknr;
 877         int ret = 0;
 878         struct buffer_head *bh;
 879         int fc_off;
 880
 881         *bh_out = NULL;
 882
 883         if (journal->j_fc_off + journal->j_fc_first < journal->j_fc_last) {
 884                 fc_off = journal->j_fc_off;
 885                 blocknr = journal->j_fc_first + fc_off;
 886                 journal->j_fc_off++;
 887         } else {
 888                 ret = -EINVAL;
 889         }
 890
 891         if (ret)
 892                 return ret;
 893
 894         ret = jbd2_journal_bmap(journal, blocknr, &pblock);
 895         if (ret)
 896                 return ret;
 897
 898         bh = __getblk(journal->j_dev, pblock, journal->j_blocksize);
 899         if (!bh)
 900                 return -ENOMEM;
 901
 902
 903         journal->j_fc_wbuf[fc_off] = bh;
 904
 905         *bh_out = bh;
 906
 907         return 0;
 908 }
 909 EXPORT_SYMBOL(jbd2_fc_get_buf);
 910
 911 /*
 912  * Wait on fast commit buffers that were allocated by jbd2_fc_get_buf
 913  * for completion.
 914  */
 915 int jbd2_fc_wait_bufs(journal_t *journal, int num_blks)
 916 {
 917         struct buffer_head *bh;
 918         int i, j_fc_off;
 919
 920         j_fc_off = journal->j_fc_off;
 921
 922         /*
 923          * Wait in reverse order to minimize chances of us being woken up before
 924          * all IOs have completed
 925          */
 926         for (i = j_fc_off - 1; i >= j_fc_off - num_blks; i--) {
 927                 bh = journal->j_fc_wbuf[i];
 928                 wait_on_buffer(bh);
 929                 put_bh(bh);
 930                 journal->j_fc_wbuf[i] = NULL;
 931                 if (unlikely(!buffer_uptodate(bh)))
 932                         return -EIO;
 933         }
 934
 935         return 0;
 936 }
 937 EXPORT_SYMBOL(jbd2_fc_wait_bufs);
 938
 939 int jbd2_fc_release_bufs(journal_t *journal)
 940 {
 941         struct buffer_head *bh;
 942         int i, j_fc_off;
 943
 944         j_fc_off = journal->j_fc_off;
 945
 946         for (i = j_fc_off - 1; i >= 0; i--) {
 947                 bh = journal->j_fc_wbuf[i];
 948                 if (!bh)
 949                         break;
 950                 put_bh(bh);
 951                 journal->j_fc_wbuf[i] = NULL;
 952         }
 953
 954         return 0;
 955 }
 956 EXPORT_SYMBOL(jbd2_fc_release_bufs);
 957
 958 /*
 959  * Conversion of logical to physical block numbers for the journal
 960  *
 961  * On external journals the journal blocks are identity-mapped, so
 962  * this is a no-op.  If needed, we can use j_blk_offset - everything is
 963  * ready.
 964  */
 965 int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
 966                  unsigned long long *retp)
 967 {
 968         int err = 0;
 969         unsigned long long ret;
 970         sector_t block = 0;
 971
 972         if (journal->j_inode) {
 973                 block = blocknr;
 974                 ret = bmap(journal->j_inode, &block);
 975
 976                 if (ret || !block) {
 977                         printk(KERN_ALERT "%s: journal block not found "
 978                                         "at offset %lu on %s\n",
 979                                __func__, blocknr, journal->j_devname);
 980                         err = -EIO;
 981                         jbd2_journal_abort(journal, err);
 982                 } else {
 983                         *retp = block;
 984                 }
 985
 986         } else {
 987                 *retp = blocknr; /* +journal->j_blk_offset */
 988         }
 989         return err;
 990 }
 991
 992 /*
 993  * We play buffer_head aliasing tricks to write data/metadata blocks to
 994  * the journal without copying their contents, but for journal
 995  * descriptor blocks we do need to generate bona fide buffers.
 996  *
 997  * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
 998  * the buffer's contents they really should run flush_dcache_page(bh->b_page).
 999  * But we don't bother doing that, so there will be coherency problems with
1000  * mmaps of blockdevs which hold live JBD-controlled filesystems.
1001  */
1002 struct buffer_head *
1003 jbd2_journal_get_descriptor_buffer(transaction_t *transaction, int type)
1004 {
1005         journal_t *journal = transaction->t_journal;
1006         struct buffer_head *bh;
1007         unsigned long long blocknr;
1008         journal_header_t *header;
1009         int err;
1010
1011         err = jbd2_journal_next_log_block(journal, &blocknr);
1012
1013         if (err)
1014                 return NULL;
1015
1016         bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
1017         if (!bh)
1018                 return NULL;
1019         atomic_dec(&transaction->t_outstanding_credits);
1020         lock_buffer(bh);
1021         memset(bh->b_data, 0, journal->j_blocksize);
1022         header = (journal_header_t *)bh->b_data;
1023         header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
1024         header->h_blocktype = cpu_to_be32(type);
1025         header->h_sequence = cpu_to_be32(transaction->t_tid);
1026         set_buffer_uptodate(bh);
1027         unlock_buffer(bh);
1028         BUFFER_TRACE(bh, "return this buffer");
1029         return bh;
1030 }
1031
1032 void jbd2_descriptor_block_csum_set(journal_t *j, struct buffer_head *bh)
1033 {
1034         struct jbd2_journal_block_tail *tail;
1035         __u32 csum;
1036
1037         if (!jbd2_journal_has_csum_v2or3(j))
1038                 return;
1039
1040         tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize -
1041                         sizeof(struct jbd2_journal_block_tail));
1042         tail->t_checksum = 0;
1043         csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
1044         tail->t_checksum = cpu_to_be32(csum);
1045 }
1046
1047 /*
1048  * Return tid of the oldest transaction in the journal and block in the journal
1049  * where the transaction starts.
1050  *
1051  * If the journal is now empty, return which will be the next transaction ID
1052  * we will write and where will that transaction start.
1053  *
1054  * The return value is 0 if journal tail cannot be pushed any further, 1 if
1055  * it can.
1056  */
1057 int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
1058                               unsigned long *block)
1059 {
1060         transaction_t *transaction;
1061         int ret;
1062
1063         read_lock(&journal->j_state_lock);
1064         spin_lock(&journal->j_list_lock);
1065         transaction = journal->j_checkpoint_transactions;
1066         if (transaction) {
1067                 *tid = transaction->t_tid;
1068                 *block = transaction->t_log_start;
1069         } else if ((transaction = journal->j_committing_transaction) != NULL) {
1070                 *tid = transaction->t_tid;
1071                 *block = transaction->t_log_start;
1072         } else if ((transaction = journal->j_running_transaction) != NULL) {
1073                 *tid = transaction->t_tid;
1074                 *block = journal->j_head;
1075         } else {
1076                 *tid = journal->j_transaction_sequence;
1077                 *block = journal->j_head;
1078         }
1079         ret = tid_gt(*tid, journal->j_tail_sequence);
1080         spin_unlock(&journal->j_list_lock);
1081         read_unlock(&journal->j_state_lock);
1082
1083         return ret;
1084 }
1085
1086 /*
1087  * Update information in journal structure and in on disk journal superblock
1088  * about log tail. This function does not check whether information passed in
1089  * really pushes log tail further. It's responsibility of the caller to make
1090  * sure provided log tail information is valid (e.g. by holding
1091  * j_checkpoint_mutex all the time between computing log tail and calling this
1092  * function as is the case with jbd2_cleanup_journal_tail()).
1093  *
1094  * Requires j_checkpoint_mutex
1095  */
1096 int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
1097 {
1098         unsigned long freed;
1099         int ret;
1100
1101         BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1102
1103         /*
1104          * We cannot afford for write to remain in drive's caches since as
1105          * soon as we update j_tail, next transaction can start reusing journal
1106          * space and if we lose sb update during power failure we'd replay
1107          * old transaction with possibly newly overwritten data.
1108          */
1109         ret = jbd2_journal_update_sb_log_tail(journal, tid, block,
1110                                               REQ_SYNC | REQ_FUA);
1111         if (ret)
1112                 goto out;
1113
1114         write_lock(&journal->j_state_lock);
1115         freed = block - journal->j_tail;
1116         if (block < journal->j_tail)
1117                 freed += journal->j_last - journal->j_first;
1118
1119         trace_jbd2_update_log_tail(journal, tid, block, freed);
1120         jbd_debug(1,
1121                   "Cleaning journal tail from %u to %u (offset %lu), "
1122                   "freeing %lu\n",
1123                   journal->j_tail_sequence, tid, block, freed);
1124
1125         journal->j_free += freed;
1126         journal->j_tail_sequence = tid;
1127         journal->j_tail = block;
1128         write_unlock(&journal->j_state_lock);
1129
1130 out:
1131         return ret;
1132 }
1133
1134 /*
1135  * This is a variation of __jbd2_update_log_tail which checks for validity of
1136  * provided log tail and locks j_checkpoint_mutex. So it is safe against races
1137  * with other threads updating log tail.
1138  */
1139 void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
1140 {
1141         mutex_lock_io(&journal->j_checkpoint_mutex);
1142         if (tid_gt(tid, journal->j_tail_sequence))
1143                 __jbd2_update_log_tail(journal, tid, block);
1144         mutex_unlock(&journal->j_checkpoint_mutex);
1145 }
1146
1147 struct jbd2_stats_proc_session {
1148         journal_t *journal;
1149         struct transaction_stats_s *stats;
1150         int start;
1151         int max;
1152 };
1153
1154 static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos)
1155 {
1156         return *pos ? NULL : SEQ_START_TOKEN;
1157 }
1158
1159 static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos)
1160 {
1161         (*pos)++;
1162         return NULL;
1163 }
1164
1165 static int jbd2_seq_info_show(struct seq_file *seq, void *v)
1166 {
1167         struct jbd2_stats_proc_session *s = seq->private;
1168
1169         if (v != SEQ_START_TOKEN)
1170                 return 0;
1171         seq_printf(seq, "%lu transactions (%lu requested), "
1172                    "each up to %u blocks\n",
1173                    s->stats->ts_tid, s->stats->ts_requested,
1174                    s->journal->j_max_transaction_buffers);
1175         if (s->stats->ts_tid == 0)
1176                 return 0;
1177         seq_printf(seq, "average: \n  %ums waiting for transaction\n",
1178             jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid));
1179         seq_printf(seq, "  %ums request delay\n",
1180             (s->stats->ts_requested == 0) ? 0 :
1181             jiffies_to_msecs(s->stats->run.rs_request_delay /
1182                              s->stats->ts_requested));
1183         seq_printf(seq, "  %ums running transaction\n",
1184             jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid));
1185         seq_printf(seq, "  %ums transaction was being locked\n",
1186             jiffies_to_msecs(s->stats->run.rs_locked / s->stats->ts_tid));
1187         seq_printf(seq, "  %ums flushing data (in ordered mode)\n",
1188             jiffies_to_msecs(s->stats->run.rs_flushing / s->stats->ts_tid));
1189         seq_printf(seq, "  %ums logging transaction\n",
1190             jiffies_to_msecs(s->stats->run.rs_logging / s->stats->ts_tid));
1191         seq_printf(seq, "  %lluus average transaction commit time\n",
1192                    div_u64(s->journal->j_average_commit_time, 1000));
1193         seq_printf(seq, "  %lu handles per transaction\n",
1194             s->stats->run.rs_handle_count / s->stats->ts_tid);
1195         seq_printf(seq, "  %lu blocks per transaction\n",
1196             s->stats->run.rs_blocks / s->stats->ts_tid);
1197         seq_printf(seq, "  %lu logged blocks per transaction\n",
1198             s->stats->run.rs_blocks_logged / s->stats->ts_tid);
1199         return 0;
1200 }
1201
1202 static void jbd2_seq_info_stop(struct seq_file *seq, void *v)
1203 {
1204 }
1205
1206 static const struct seq_operations jbd2_seq_info_ops = {
1207         .start  = jbd2_seq_info_start,
1208         .next   = jbd2_seq_info_next,
1209         .stop   = jbd2_seq_info_stop,
1210         .show   = jbd2_seq_info_show,
1211 };
1212
1213 static int jbd2_seq_info_open(struct inode *inode, struct file *file)
1214 {
1215         journal_t *journal = pde_data(inode);
1216         struct jbd2_stats_proc_session *s;
1217         int rc, size;
1218
1219         s = kmalloc(sizeof(*s), GFP_KERNEL);
1220         if (s == NULL)
1221                 return -ENOMEM;
1222         size = sizeof(struct transaction_stats_s);
1223         s->stats = kmalloc(size, GFP_KERNEL);
1224         if (s->stats == NULL) {
1225                 kfree(s);
1226                 return -ENOMEM;
1227         }
1228         spin_lock(&journal->j_history_lock);
1229         memcpy(s->stats, &journal->j_stats, size);
1230         s->journal = journal;
1231         spin_unlock(&journal->j_history_lock);
1232
1233         rc = seq_open(file, &jbd2_seq_info_ops);
1234         if (rc == 0) {
1235                 struct seq_file *m = file->private_data;
1236                 m->private = s;
1237         } else {
1238                 kfree(s->stats);
1239                 kfree(s);
1240         }
1241         return rc;
1242
1243 }
1244
1245 static int jbd2_seq_info_release(struct inode *inode, struct file *file)
1246 {
1247         struct seq_file *seq = file->private_data;
1248         struct jbd2_stats_proc_session *s = seq->private;
1249         kfree(s->stats);
1250         kfree(s);
1251         return seq_release(inode, file);
1252 }
1253
1254 static const struct proc_ops jbd2_info_proc_ops = {
1255         .proc_open      = jbd2_seq_info_open,
1256         .proc_read      = seq_read,
1257         .proc_lseek     = seq_lseek,
1258         .proc_release   = jbd2_seq_info_release,
1259 };
1260
1261 static struct proc_dir_entry *proc_jbd2_stats;
1262
1263 static void jbd2_stats_proc_init(journal_t *journal)
1264 {
1265         journal->j_proc_entry = proc_mkdir(journal->j_devname, proc_jbd2_stats);
1266         if (journal->j_proc_entry) {
1267                 proc_create_data("info", S_IRUGO, journal->j_proc_entry,
1268                                  &jbd2_info_proc_ops, journal);
1269         }
1270 }
1271
1272 static void jbd2_stats_proc_exit(journal_t *journal)
1273 {
1274         remove_proc_entry("info", journal->j_proc_entry);
1275         remove_proc_entry(journal->j_devname, proc_jbd2_stats);
1276 }
1277
1278 /* Minimum size of descriptor tag */
1279 static int jbd2_min_tag_size(void)
1280 {
1281         /*
1282          * Tag with 32-bit block numbers does not use last four bytes of the
1283          * structure
1284          */
1285         return sizeof(journal_block_tag_t) - 4;
1286 }
1287
1288 /**
1289  * jbd2_journal_shrink_scan()
1290  * @shrink: shrinker to work on
1291  * @sc: reclaim request to process
1292  *
1293  * Scan the checkpointed buffer on the checkpoint list and release the
1294  * journal_head.
1295  */
1296 static unsigned long jbd2_journal_shrink_scan(struct shrinker *shrink,
1297                                               struct shrink_control *sc)
1298 {
1299         journal_t *journal = container_of(shrink, journal_t, j_shrinker);
1300         unsigned long nr_to_scan = sc->nr_to_scan;
1301         unsigned long nr_shrunk;
1302         unsigned long count;
1303
1304         count = percpu_counter_read_positive(&journal->j_checkpoint_jh_count);
1305         trace_jbd2_shrink_scan_enter(journal, sc->nr_to_scan, count);
1306
1307         nr_shrunk = jbd2_journal_shrink_checkpoint_list(journal, &nr_to_scan);
1308
1309         count = percpu_counter_read_positive(&journal->j_checkpoint_jh_count);
1310         trace_jbd2_shrink_scan_exit(journal, nr_to_scan, nr_shrunk, count);
1311
1312         return nr_shrunk;
1313 }
1314
1315 /**
1316  * jbd2_journal_shrink_count()
1317  * @shrink: shrinker to work on
1318  * @sc: reclaim request to process
1319  *
1320  * Count the number of checkpoint buffers on the checkpoint list.
1321  */
1322 static unsigned long jbd2_journal_shrink_count(struct shrinker *shrink,
1323                                                struct shrink_control *sc)
1324 {
1325         journal_t *journal = container_of(shrink, journal_t, j_shrinker);
1326         unsigned long count;
1327
1328         count = percpu_counter_read_positive(&journal->j_checkpoint_jh_count);
1329         trace_jbd2_shrink_count(journal, sc->nr_to_scan, count);
1330
1331         return count;
1332 }
1333
1334 /*
1335  * Management for journal control blocks: functions to create and
1336  * destroy journal_t structures, and to initialise and read existing
1337  * journal blocks from disk.  */
1338
1339 /* First: create and setup a journal_t object in memory.  We initialise
1340  * very few fields yet: that has to wait until we have created the
1341  * journal structures from from scratch, or loaded them from disk. */
1342
1343 static journal_t *journal_init_common(struct block_device *bdev,
1344                         struct block_device *fs_dev,
1345                         unsigned long long start, int len, int blocksize)
1346 {
1347         static struct lock_class_key jbd2_trans_commit_key;
1348         journal_t *journal;
1349         int err;
1350         struct buffer_head *bh;
1351         int n;
1352
1353         journal = kzalloc(sizeof(*journal), GFP_KERNEL);
1354         if (!journal)
1355                 return NULL;
1356
1357         init_waitqueue_head(&journal->j_wait_transaction_locked);
1358         init_waitqueue_head(&journal->j_wait_done_commit);
1359         init_waitqueue_head(&journal->j_wait_commit);
1360         init_waitqueue_head(&journal->j_wait_updates);
1361         init_waitqueue_head(&journal->j_wait_reserved);
1362         init_waitqueue_head(&journal->j_fc_wait);
1363         mutex_init(&journal->j_abort_mutex);
1364         mutex_init(&journal->j_barrier);
1365         mutex_init(&journal->j_checkpoint_mutex);
1366         spin_lock_init(&journal->j_revoke_lock);
1367         spin_lock_init(&journal->j_list_lock);
1368         rwlock_init(&journal->j_state_lock);
1369
1370         journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE);
1371         journal->j_min_batch_time = 0;
1372         journal->j_max_batch_time = 15000; /* 15ms */
1373         atomic_set(&journal->j_reserved_credits, 0);
1374
1375         /* The journal is marked for error until we succeed with recovery! */
1376         journal->j_flags = JBD2_ABORT;
1377
1378         /* Set up a default-sized revoke table for the new mount. */
1379         err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
1380         if (err)
1381                 goto err_cleanup;
1382
1383         spin_lock_init(&journal->j_history_lock);
1384
1385         lockdep_init_map(&journal->j_trans_commit_map, "jbd2_handle",
1386                          &jbd2_trans_commit_key, 0);
1387
1388         /* journal descriptor can store up to n blocks -bzzz */
1389         journal->j_blocksize = blocksize;
1390         journal->j_dev = bdev;
1391         journal->j_fs_dev = fs_dev;
1392         journal->j_blk_offset = start;
1393         journal->j_total_len = len;
1394         /* We need enough buffers to write out full descriptor block. */
1395         n = journal->j_blocksize / jbd2_min_tag_size();
1396         journal->j_wbufsize = n;
1397         journal->j_fc_wbuf = NULL;
1398         journal->j_wbuf = kmalloc_array(n, sizeof(struct buffer_head *),
1399                                         GFP_KERNEL);
1400         if (!journal->j_wbuf)
1401                 goto err_cleanup;
1402
1403         bh = getblk_unmovable(journal->j_dev, start, journal->j_blocksize);
1404         if (!bh) {
1405                 pr_err("%s: Cannot get buffer for journal superblock\n",
1406                         __func__);
1407                 goto err_cleanup;
1408         }
1409         journal->j_sb_buffer = bh;
1410         journal->j_superblock = (journal_superblock_t *)bh->b_data;
1411
1412         journal->j_shrink_transaction = NULL;
1413         journal->j_shrinker.scan_objects = jbd2_journal_shrink_scan;
1414         journal->j_shrinker.count_objects = jbd2_journal_shrink_count;
1415         journal->j_shrinker.seeks = DEFAULT_SEEKS;
1416         journal->j_shrinker.batch = journal->j_max_transaction_buffers;
1417
1418         if (percpu_counter_init(&journal->j_checkpoint_jh_count, 0, GFP_KERNEL))
1419                 goto err_cleanup;
1420
1421         if (register_shrinker(&journal->j_shrinker)) {
1422                 percpu_counter_destroy(&journal->j_checkpoint_jh_count);
1423                 goto err_cleanup;
1424         }
1425         return journal;
1426
1427 err_cleanup:
1428         brelse(journal->j_sb_buffer);
1429         kfree(journal->j_wbuf);
1430         jbd2_journal_destroy_revoke(journal);
1431         kfree(journal);
1432         return NULL;
1433 }
1434
1435 /* jbd2_journal_init_dev and jbd2_journal_init_inode:
1436  *
1437  * Create a journal structure assigned some fixed set of disk blocks to
1438  * the journal.  We don't actually touch those disk blocks yet, but we
1439  * need to set up all of the mapping information to tell the journaling
1440  * system where the journal blocks are.
1441  *
1442  */
1443
1444 /**
1445  *  journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
1446  *  @bdev: Block device on which to create the journal
1447  *  @fs_dev: Device which hold journalled filesystem for this journal.
1448  *  @start: Block nr Start of journal.
1449  *  @len:  Length of the journal in blocks.
1450  *  @blocksize: blocksize of journalling device
1451  *
1452  *  Returns: a newly created journal_t *
1453  *
1454  *  jbd2_journal_init_dev creates a journal which maps a fixed contiguous
1455  *  range of blocks on an arbitrary block device.
1456  *
1457  */
1458 journal_t *jbd2_journal_init_dev(struct block_device *bdev,
1459                         struct block_device *fs_dev,
1460                         unsigned long long start, int len, int blocksize)
1461 {
1462         journal_t *journal;
1463
1464         journal = journal_init_common(bdev, fs_dev, start, len, blocksize);
1465         if (!journal)
1466                 return NULL;
1467
1468         bdevname(journal->j_dev, journal->j_devname);
1469         strreplace(journal->j_devname, '/', '!');
1470         jbd2_stats_proc_init(journal);
1471
1472         return journal;
1473 }
1474
1475 /**
1476  *  journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
1477  *  @inode: An inode to create the journal in
1478  *
1479  * jbd2_journal_init_inode creates a journal which maps an on-disk inode as
1480  * the journal.  The inode must exist already, must support bmap() and
1481  * must have all data blocks preallocated.
1482  */
1483 journal_t *jbd2_journal_init_inode(struct inode *inode)
1484 {
1485         journal_t *journal;
1486         sector_t blocknr;
1487         char *p;
1488         int err = 0;
1489
1490         blocknr = 0;
1491         err = bmap(inode, &blocknr);
1492
1493         if (err || !blocknr) {
1494                 pr_err("%s: Cannot locate journal superblock\n",
1495                         __func__);
1496                 return NULL;
1497         }
1498
1499         jbd_debug(1, "JBD2: inode %s/%ld, size %lld, bits %d, blksize %ld\n",
1500                   inode->i_sb->s_id, inode->i_ino, (long long) inode->i_size,
1501                   inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
1502
1503         journal = journal_init_common(inode->i_sb->s_bdev, inode->i_sb->s_bdev,
1504                         blocknr, inode->i_size >> inode->i_sb->s_blocksize_bits,
1505                         inode->i_sb->s_blocksize);
1506         if (!journal)
1507                 return NULL;
1508
1509         journal->j_inode = inode;
1510         bdevname(journal->j_dev, journal->j_devname);
1511         p = strreplace(journal->j_devname, '/', '!');
1512         sprintf(p, "-%lu", journal->j_inode->i_ino);
1513         jbd2_stats_proc_init(journal);
1514
1515         return journal;
1516 }
1517
1518 /*
1519  * If the journal init or create aborts, we need to mark the journal
1520  * superblock as being NULL to prevent the journal destroy from writing
1521  * back a bogus superblock.
1522  */
1523 static void journal_fail_superblock(journal_t *journal)
1524 {
1525         struct buffer_head *bh = journal->j_sb_buffer;
1526         brelse(bh);
1527         journal->j_sb_buffer = NULL;
1528 }
1529
1530 /*
1531  * Given a journal_t structure, initialise the various fields for
1532  * startup of a new journaling session.  We use this both when creating
1533  * a journal, and after recovering an old journal to reset it for
1534  * subsequent use.
1535  */
1536
1537 static int journal_reset(journal_t *journal)
1538 {
1539         journal_superblock_t *sb = journal->j_superblock;
1540         unsigned long long first, last;
1541
1542         first = be32_to_cpu(sb->s_first);
1543         last = be32_to_cpu(sb->s_maxlen);
1544         if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) {
1545                 printk(KERN_ERR "JBD2: Journal too short (blocks %llu-%llu).\n",
1546                        first, last);
1547                 journal_fail_superblock(journal);
1548                 return -EINVAL;
1549         }
1550
1551         journal->j_first = first;
1552         journal->j_last = last;
1553
1554         journal->j_head = journal->j_first;
1555         journal->j_tail = journal->j_first;
1556         journal->j_free = journal->j_last - journal->j_first;
1557
1558         journal->j_tail_sequence = journal->j_transaction_sequence;
1559         journal->j_commit_sequence = journal->j_transaction_sequence - 1;
1560         journal->j_commit_request = journal->j_commit_sequence;
1561
1562         journal->j_max_transaction_buffers = jbd2_journal_get_max_txn_bufs(journal);
1563
1564         /*
1565          * Now that journal recovery is done, turn fast commits off here. This
1566          * way, if fast commit was enabled before the crash but if now FS has
1567          * disabled it, we don't enable fast commits.
1568          */
1569         jbd2_clear_feature_fast_commit(journal);
1570
1571         /*
1572          * As a special case, if the on-disk copy is already marked as needing
1573          * no recovery (s_start == 0), then we can safely defer the superblock
1574          * update until the next commit by setting JBD2_FLUSHED.  This avoids
1575          * attempting a write to a potential-readonly device.
1576          */
1577         if (sb->s_start == 0) {
1578                 jbd_debug(1, "JBD2: Skipping superblock update on recovered sb "
1579                         "(start %ld, seq %u, errno %d)\n",
1580                         journal->j_tail, journal->j_tail_sequence,
1581                         journal->j_errno);
1582                 journal->j_flags |= JBD2_FLUSHED;
1583         } else {
1584                 /* Lock here to make assertions happy... */
1585                 mutex_lock_io(&journal->j_checkpoint_mutex);
1586                 /*
1587                  * Update log tail information. We use REQ_FUA since new
1588                  * transaction will start reusing journal space and so we
1589                  * must make sure information about current log tail is on
1590                  * disk before that.
1591                  */
1592                 jbd2_journal_update_sb_log_tail(journal,
1593                                                 journal->j_tail_sequence,
1594                                                 journal->j_tail,
1595                                                 REQ_SYNC | REQ_FUA);
1596                 mutex_unlock(&journal->j_checkpoint_mutex);
1597         }
1598         return jbd2_journal_start_thread(journal);
1599 }
1600
1601 /*
1602  * This function expects that the caller will have locked the journal
1603  * buffer head, and will return with it unlocked
1604  */
1605 static int jbd2_write_superblock(journal_t *journal, int write_flags)
1606 {
1607         struct buffer_head *bh = journal->j_sb_buffer;
1608         journal_superblock_t *sb = journal->j_superblock;
1609         int ret;
1610
1611         /* Buffer got discarded which means block device got invalidated */
1612         if (!buffer_mapped(bh)) {
1613                 unlock_buffer(bh);
1614                 return -EIO;
1615         }
1616
1617         trace_jbd2_write_superblock(journal, write_flags);
1618         if (!(journal->j_flags & JBD2_BARRIER))
1619                 write_flags &= ~(REQ_FUA | REQ_PREFLUSH);
1620         if (buffer_write_io_error(bh)) {
1621                 /*
1622                  * Oh, dear.  A previous attempt to write the journal
1623                  * superblock failed.  This could happen because the
1624                  * USB device was yanked out.  Or it could happen to
1625                  * be a transient write error and maybe the block will
1626                  * be remapped.  Nothing we can do but to retry the
1627                  * write and hope for the best.
1628                  */
1629                 printk(KERN_ERR "JBD2: previous I/O error detected "
1630                        "for journal superblock update for %s.\n",
1631                        journal->j_devname);
1632                 clear_buffer_write_io_error(bh);
1633                 set_buffer_uptodate(bh);
1634         }
1635         if (jbd2_journal_has_csum_v2or3(journal))
1636                 sb->s_checksum = jbd2_superblock_csum(journal, sb);
1637         get_bh(bh);
1638         bh->b_end_io = end_buffer_write_sync;
1639         ret = submit_bh(REQ_OP_WRITE, write_flags, bh);
1640         wait_on_buffer(bh);
1641         if (buffer_write_io_error(bh)) {
1642                 clear_buffer_write_io_error(bh);
1643                 set_buffer_uptodate(bh);
1644                 ret = -EIO;
1645         }
1646         if (ret) {
1647                 printk(KERN_ERR "JBD2: Error %d detected when updating "
1648                        "journal superblock for %s.\n", ret,
1649                        journal->j_devname);
1650                 if (!is_journal_aborted(journal))
1651                         jbd2_journal_abort(journal, ret);
1652         }
1653
1654         return ret;
1655 }
1656
1657 /**
1658  * jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk.
1659  * @journal: The journal to update.
1660  * @tail_tid: TID of the new transaction at the tail of the log
1661  * @tail_block: The first block of the transaction at the tail of the log
1662  * @write_op: With which operation should we write the journal sb
1663  *
1664  * Update a journal's superblock information about log tail and write it to
1665  * disk, waiting for the IO to complete.
1666  */
1667 int jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
1668                                      unsigned long tail_block, int write_op)
1669 {
1670         journal_superblock_t *sb = journal->j_superblock;
1671         int ret;
1672
1673         if (is_journal_aborted(journal))
1674                 return -EIO;
1675         if (test_bit(JBD2_CHECKPOINT_IO_ERROR, &journal->j_atomic_flags)) {
1676                 jbd2_journal_abort(journal, -EIO);
1677                 return -EIO;
1678         }
1679
1680         BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1681         jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
1682                   tail_block, tail_tid);
1683
1684         lock_buffer(journal->j_sb_buffer);
1685         sb->s_sequence = cpu_to_be32(tail_tid);
1686         sb->s_start    = cpu_to_be32(tail_block);
1687
1688         ret = jbd2_write_superblock(journal, write_op);
1689         if (ret)
1690                 goto out;
1691
1692         /* Log is no longer empty */
1693         write_lock(&journal->j_state_lock);
1694         WARN_ON(!sb->s_sequence);
1695         journal->j_flags &= ~JBD2_FLUSHED;
1696         write_unlock(&journal->j_state_lock);
1697
1698 out:
1699         return ret;
1700 }
1701
1702 /**
1703  * jbd2_mark_journal_empty() - Mark on disk journal as empty.
1704  * @journal: The journal to update.
1705  * @write_op: With which operation should we write the journal sb
1706  *
1707  * Update a journal's dynamic superblock fields to show that journal is empty.
1708  * Write updated superblock to disk waiting for IO to complete.
1709  */
1710 static void jbd2_mark_journal_empty(journal_t *journal, int write_op)
1711 {
1712         journal_superblock_t *sb = journal->j_superblock;
1713         bool had_fast_commit = false;
1714
1715         BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1716         lock_buffer(journal->j_sb_buffer);
1717         if (sb->s_start == 0) {         /* Is it already empty? */
1718                 unlock_buffer(journal->j_sb_buffer);
1719                 return;
1720         }
1721
1722         jbd_debug(1, "JBD2: Marking journal as empty (seq %u)\n",
1723                   journal->j_tail_sequence);
1724
1725         sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
1726         sb->s_start    = cpu_to_be32(0);
1727         if (jbd2_has_feature_fast_commit(journal)) {
1728                 /*
1729                  * When journal is clean, no need to commit fast commit flag and
1730                  * make file system incompatible with older kernels.
1731                  */
1732                 jbd2_clear_feature_fast_commit(journal);
1733                 had_fast_commit = true;
1734         }
1735
1736         jbd2_write_superblock(journal, write_op);
1737
1738         if (had_fast_commit)
1739                 jbd2_set_feature_fast_commit(journal);
1740
1741         /* Log is no longer empty */
1742         write_lock(&journal->j_state_lock);
1743         journal->j_flags |= JBD2_FLUSHED;
1744         write_unlock(&journal->j_state_lock);
1745 }
1746
1747 /**
1748  * __jbd2_journal_erase() - Discard or zeroout journal blocks (excluding superblock)
1749  * @journal: The journal to erase.
1750  * @flags: A discard/zeroout request is sent for each physically contigous
1751  *      region of the journal. Either JBD2_JOURNAL_FLUSH_DISCARD or
1752  *      JBD2_JOURNAL_FLUSH_ZEROOUT must be set to determine which operation
1753  *      to perform.
1754  *
1755  * Note: JBD2_JOURNAL_FLUSH_ZEROOUT attempts to use hardware offload. Zeroes
1756  * will be explicitly written if no hardware offload is available, see
1757  * blkdev_issue_zeroout for more details.
1758  */
1759 static int __jbd2_journal_erase(journal_t *journal, unsigned int flags)
1760 {
1761         int err = 0;
1762         unsigned long block, log_offset; /* logical */
1763         unsigned long long phys_block, block_start, block_stop; /* physical */
1764         loff_t byte_start, byte_stop, byte_count;
1765
1766         /* flags must be set to either discard or zeroout */
1767         if ((flags & ~JBD2_JOURNAL_FLUSH_VALID) || !flags ||
1768                         ((flags & JBD2_JOURNAL_FLUSH_DISCARD) &&
1769                         (flags & JBD2_JOURNAL_FLUSH_ZEROOUT)))
1770                 return -EINVAL;
1771
1772         if ((flags & JBD2_JOURNAL_FLUSH_DISCARD) &&
1773             !bdev_max_discard_sectors(journal->j_dev))
1774                 return -EOPNOTSUPP;
1775
1776         /*
1777          * lookup block mapping and issue discard/zeroout for each
1778          * contiguous region
1779          */
1780         log_offset = be32_to_cpu(journal->j_superblock->s_first);
1781         block_start =  ~0ULL;
1782         for (block = log_offset; block < journal->j_total_len; block++) {
1783                 err = jbd2_journal_bmap(journal, block, &phys_block);
1784                 if (err) {
1785                         pr_err("JBD2: bad block at offset %lu", block);
1786                         return err;
1787                 }
1788
1789                 if (block_start == ~0ULL) {
1790                         block_start = phys_block;
1791                         block_stop = block_start - 1;
1792                 }
1793
1794                 /*
1795                  * last block not contiguous with current block,
1796                  * process last contiguous region and return to this block on
1797                  * next loop
1798                  */
1799                 if (phys_block != block_stop + 1) {
1800                         block--;
1801                 } else {
1802                         block_stop++;
1803                         /*
1804                          * if this isn't the last block of journal,
1805                          * no need to process now because next block may also
1806                          * be part of this contiguous region
1807                          */
1808                         if (block != journal->j_total_len - 1)
1809                                 continue;
1810                 }
1811
1812                 /*
1813                  * end of contiguous region or this is last block of journal,
1814                  * take care of the region
1815                  */
1816                 byte_start = block_start * journal->j_blocksize;
1817                 byte_stop = block_stop * journal->j_blocksize;
1818                 byte_count = (block_stop - block_start + 1) *
1819                                 journal->j_blocksize;
1820
1821                 truncate_inode_pages_range(journal->j_dev->bd_inode->i_mapping,
1822                                 byte_start, byte_stop);
1823
1824                 if (flags & JBD2_JOURNAL_FLUSH_DISCARD) {
1825                         err = blkdev_issue_discard(journal->j_dev,
1826                                         byte_start >> SECTOR_SHIFT,
1827                                         byte_count >> SECTOR_SHIFT,
1828                                         GFP_NOFS);
1829                 } else if (flags & JBD2_JOURNAL_FLUSH_ZEROOUT) {
1830                         err = blkdev_issue_zeroout(journal->j_dev,
1831                                         byte_start >> SECTOR_SHIFT,
1832                                         byte_count >> SECTOR_SHIFT,
1833                                         GFP_NOFS, 0);
1834                 }
1835
1836                 if (unlikely(err != 0)) {
1837                         pr_err("JBD2: (error %d) unable to wipe journal at physical blocks %llu - %llu",
1838                                         err, block_start, block_stop);
1839                         return err;
1840                 }
1841
1842                 /* reset start and stop after processing a region */
1843                 block_start = ~0ULL;
1844         }
1845
1846         return blkdev_issue_flush(journal->j_dev);
1847 }
1848
1849 /**
1850  * jbd2_journal_update_sb_errno() - Update error in the journal.
1851  * @journal: The journal to update.
1852  *
1853  * Update a journal's errno.  Write updated superblock to disk waiting for IO
1854  * to complete.
1855  */
1856 void jbd2_journal_update_sb_errno(journal_t *journal)
1857 {
1858         journal_superblock_t *sb = journal->j_superblock;
1859         int errcode;
1860
1861         lock_buffer(journal->j_sb_buffer);
1862         errcode = journal->j_errno;
1863         if (errcode == -ESHUTDOWN)
1864                 errcode = 0;
1865         jbd_debug(1, "JBD2: updating superblock error (errno %d)\n", errcode);
1866         sb->s_errno    = cpu_to_be32(errcode);
1867
1868         jbd2_write_superblock(journal, REQ_SYNC | REQ_FUA);
1869 }
1870 EXPORT_SYMBOL(jbd2_journal_update_sb_errno);
1871
1872 static int journal_revoke_records_per_block(journal_t *journal)
1873 {
1874         int record_size;
1875         int space = journal->j_blocksize - sizeof(jbd2_journal_revoke_header_t);
1876
1877         if (jbd2_has_feature_64bit(journal))
1878                 record_size = 8;
1879         else
1880                 record_size = 4;
1881
1882         if (jbd2_journal_has_csum_v2or3(journal))
1883                 space -= sizeof(struct jbd2_journal_block_tail);
1884         return space / record_size;
1885 }
1886
1887 /*
1888  * Read the superblock for a given journal, performing initial
1889  * validation of the format.
1890  */
1891 static int journal_get_superblock(journal_t *journal)
1892 {
1893         struct buffer_head *bh;
1894         journal_superblock_t *sb;
1895         int err = -EIO;
1896
1897         bh = journal->j_sb_buffer;
1898
1899         J_ASSERT(bh != NULL);
1900         if (!buffer_uptodate(bh)) {
1901                 ll_rw_block(REQ_OP_READ, 0, 1, &bh);
1902                 wait_on_buffer(bh);
1903                 if (!buffer_uptodate(bh)) {
1904                         printk(KERN_ERR
1905                                 "JBD2: IO error reading journal superblock\n");
1906                         goto out;
1907                 }
1908         }
1909
1910         if (buffer_verified(bh))
1911                 return 0;
1912
1913         sb = journal->j_superblock;
1914
1915         err = -EINVAL;
1916
1917         if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
1918             sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1919                 printk(KERN_WARNING "JBD2: no valid journal superblock found\n");
1920                 goto out;
1921         }
1922
1923         switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1924         case JBD2_SUPERBLOCK_V1:
1925                 journal->j_format_version = 1;
1926                 break;
1927         case JBD2_SUPERBLOCK_V2:
1928                 journal->j_format_version = 2;
1929                 break;
1930         default:
1931                 printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n");
1932                 goto out;
1933         }
1934
1935         if (be32_to_cpu(sb->s_maxlen) < journal->j_total_len)
1936                 journal->j_total_len = be32_to_cpu(sb->s_maxlen);
1937         else if (be32_to_cpu(sb->s_maxlen) > journal->j_total_len) {
1938                 printk(KERN_WARNING "JBD2: journal file too short\n");
1939                 goto out;
1940         }
1941
1942         if (be32_to_cpu(sb->s_first) == 0 ||
1943             be32_to_cpu(sb->s_first) >= journal->j_total_len) {
1944                 printk(KERN_WARNING
1945                         "JBD2: Invalid start block of journal: %u\n",
1946                         be32_to_cpu(sb->s_first));
1947                 goto out;
1948         }
1949
1950         if (jbd2_has_feature_csum2(journal) &&
1951             jbd2_has_feature_csum3(journal)) {
1952                 /* Can't have checksum v2 and v3 at the same time! */
1953                 printk(KERN_ERR "JBD2: Can't enable checksumming v2 and v3 "
1954                        "at the same time!\n");
1955                 goto out;
1956         }
1957
1958         if (jbd2_journal_has_csum_v2or3_feature(journal) &&
1959             jbd2_has_feature_checksum(journal)) {
1960                 /* Can't have checksum v1 and v2 on at the same time! */
1961                 printk(KERN_ERR "JBD2: Can't enable checksumming v1 and v2/3 "
1962                        "at the same time!\n");
1963                 goto out;
1964         }
1965
1966         if (!jbd2_verify_csum_type(journal, sb)) {
1967                 printk(KERN_ERR "JBD2: Unknown checksum type\n");
1968                 goto out;
1969         }
1970
1971         /* Load the checksum driver */
1972         if (jbd2_journal_has_csum_v2or3_feature(journal)) {
1973                 journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
1974                 if (IS_ERR(journal->j_chksum_driver)) {
1975                         printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
1976                         err = PTR_ERR(journal->j_chksum_driver);
1977                         journal->j_chksum_driver = NULL;
1978                         goto out;
1979                 }
1980         }
1981
1982         if (jbd2_journal_has_csum_v2or3(journal)) {
1983                 /* Check superblock checksum */
1984                 if (sb->s_checksum != jbd2_superblock_csum(journal, sb)) {
1985                         printk(KERN_ERR "JBD2: journal checksum error\n");
1986                         err = -EFSBADCRC;
1987                         goto out;
1988                 }
1989
1990                 /* Precompute checksum seed for all metadata */
1991                 journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
1992                                                    sizeof(sb->s_uuid));
1993         }
1994
1995         journal->j_revoke_records_per_block =
1996                                 journal_revoke_records_per_block(journal);
1997         set_buffer_verified(bh);
1998
1999         return 0;
2000
2001 out:
2002         journal_fail_superblock(journal);
2003         return err;
2004 }
2005
2006 /*
2007  * Load the on-disk journal superblock and read the key fields into the
2008  * journal_t.
2009  */
2010
2011 static int load_superblock(journal_t *journal)
2012 {
2013         int err;
2014         journal_superblock_t *sb;
2015         int num_fc_blocks;
2016
2017         err = journal_get_superblock(journal);
2018         if (err)
2019                 return err;
2020
2021         sb = journal->j_superblock;
2022
2023         journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
2024         journal->j_tail = be32_to_cpu(sb->s_start);
2025         journal->j_first = be32_to_cpu(sb->s_first);
2026         journal->j_errno = be32_to_cpu(sb->s_errno);
2027         journal->j_last = be32_to_cpu(sb->s_maxlen);
2028
2029         if (jbd2_has_feature_fast_commit(journal)) {
2030                 journal->j_fc_last = be32_to_cpu(sb->s_maxlen);
2031                 num_fc_blocks = jbd2_journal_get_num_fc_blks(sb);
2032                 if (journal->j_last - num_fc_blocks >= JBD2_MIN_JOURNAL_BLOCKS)
2033                         journal->j_last = journal->j_fc_last - num_fc_blocks;
2034                 journal->j_fc_first = journal->j_last + 1;
2035                 journal->j_fc_off = 0;
2036         }
2037
2038         return 0;
2039 }
2040
2041
2042 /**
2043  * jbd2_journal_load() - Read journal from disk.
2044  * @journal: Journal to act on.
2045  *
2046  * Given a journal_t structure which tells us which disk blocks contain
2047  * a journal, read the journal from disk to initialise the in-memory
2048  * structures.
2049  */
2050 int jbd2_journal_load(journal_t *journal)
2051 {
2052         int err;
2053         journal_superblock_t *sb;
2054
2055         err = load_superblock(journal);
2056         if (err)
2057                 return err;
2058
2059         sb = journal->j_superblock;
2060         /* If this is a V2 superblock, then we have to check the
2061          * features flags on it. */
2062
2063         if (journal->j_format_version >= 2) {
2064                 if ((sb->s_feature_ro_compat &
2065                      ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) ||
2066                     (sb->s_feature_incompat &
2067                      ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) {
2068                         printk(KERN_WARNING
2069                                 "JBD2: Unrecognised features on journal\n");
2070                         return -EINVAL;
2071                 }
2072         }
2073
2074         /*
2075          * Create a slab for this blocksize
2076          */
2077         err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize));
2078         if (err)
2079                 return err;
2080
2081         /* Let the recovery code check whether it needs to recover any
2082          * data from the journal. */
2083         if (jbd2_journal_recover(journal))
2084                 goto recovery_error;
2085
2086         if (journal->j_failed_commit) {
2087                 printk(KERN_ERR "JBD2: journal transaction %u on %s "
2088                        "is corrupt.\n", journal->j_failed_commit,
2089                        journal->j_devname);
2090                 return -EFSCORRUPTED;
2091         }
2092         /*
2093          * clear JBD2_ABORT flag initialized in journal_init_common
2094          * here to update log tail information with the newest seq.
2095          */
2096         journal->j_flags &= ~JBD2_ABORT;
2097
2098         /* OK, we've finished with the dynamic journal bits:
2099          * reinitialise the dynamic contents of the superblock in memory
2100          * and reset them on disk. */
2101         if (journal_reset(journal))
2102                 goto recovery_error;
2103
2104         journal->j_flags |= JBD2_LOADED;
2105         return 0;
2106
2107 recovery_error:
2108         printk(KERN_WARNING "JBD2: recovery failed\n");
2109         return -EIO;
2110 }
2111
2112 /**
2113  * jbd2_journal_destroy() - Release a journal_t structure.
2114  * @journal: Journal to act on.
2115  *
2116  * Release a journal_t structure once it is no longer in use by the
2117  * journaled object.
2118  * Return <0 if we couldn't clean up the journal.
2119  */
2120 int jbd2_journal_destroy(journal_t *journal)
2121 {
2122         int err = 0;
2123
2124         /* Wait for the commit thread to wake up and die. */
2125         journal_kill_thread(journal);
2126
2127         /* Force a final log commit */
2128         if (journal->j_running_transaction)
2129                 jbd2_journal_commit_transaction(journal);
2130
2131         /* Force any old transactions to disk */
2132
2133         /* Totally anal locking here... */
2134         spin_lock(&journal->j_list_lock);
2135         while (journal->j_checkpoint_transactions != NULL) {
2136                 spin_unlock(&journal->j_list_lock);
2137                 mutex_lock_io(&journal->j_checkpoint_mutex);
2138                 err = jbd2_log_do_checkpoint(journal);
2139                 mutex_unlock(&journal->j_checkpoint_mutex);
2140                 /*
2141                  * If checkpointing failed, just free the buffers to avoid
2142                  * looping forever
2143                  */
2144                 if (err) {
2145                         jbd2_journal_destroy_checkpoint(journal);
2146                         spin_lock(&journal->j_list_lock);
2147                         break;
2148                 }
2149                 spin_lock(&journal->j_list_lock);
2150         }
2151
2152         J_ASSERT(journal->j_running_transaction == NULL);
2153         J_ASSERT(journal->j_committing_transaction == NULL);
2154         J_ASSERT(journal->j_checkpoint_transactions == NULL);
2155         spin_unlock(&journal->j_list_lock);
2156
2157         /*
2158          * OK, all checkpoint transactions have been checked, now check the
2159          * write out io error flag and abort the journal if some buffer failed
2160          * to write back to the original location, otherwise the filesystem
2161          * may become inconsistent.
2162          */
2163         if (!is_journal_aborted(journal) &&
2164             test_bit(JBD2_CHECKPOINT_IO_ERROR, &journal->j_atomic_flags))
2165                 jbd2_journal_abort(journal, -EIO);
2166
2167         if (journal->j_sb_buffer) {
2168                 if (!is_journal_aborted(journal)) {
2169                         mutex_lock_io(&journal->j_checkpoint_mutex);
2170
2171                         write_lock(&journal->j_state_lock);
2172                         journal->j_tail_sequence =
2173                                 ++journal->j_transaction_sequence;
2174                         write_unlock(&journal->j_state_lock);
2175
2176                         jbd2_mark_journal_empty(journal,
2177                                         REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
2178                         mutex_unlock(&journal->j_checkpoint_mutex);
2179                 } else
2180                         err = -EIO;
2181                 brelse(journal->j_sb_buffer);
2182         }
2183
2184         if (journal->j_shrinker.flags & SHRINKER_REGISTERED) {
2185                 percpu_counter_destroy(&journal->j_checkpoint_jh_count);
2186                 unregister_shrinker(&journal->j_shrinker);
2187         }
2188         if (journal->j_proc_entry)
2189                 jbd2_stats_proc_exit(journal);
2190         iput(journal->j_inode);
2191         if (journal->j_revoke)
2192                 jbd2_journal_destroy_revoke(journal);
2193         if (journal->j_chksum_driver)
2194                 crypto_free_shash(journal->j_chksum_driver);
2195         kfree(journal->j_fc_wbuf);
2196         kfree(journal->j_wbuf);
2197         kfree(journal);
2198
2199         return err;
2200 }
2201
2202
2203 /**
2204  * jbd2_journal_check_used_features() - Check if features specified are used.
2205  * @journal: Journal to check.
2206  * @compat: bitmask of compatible features
2207  * @ro: bitmask of features that force read-only mount
2208  * @incompat: bitmask of incompatible features
2209  *
2210  * Check whether the journal uses all of a given set of
2211  * features.  Return true (non-zero) if it does.
2212  **/
2213
2214 int jbd2_journal_check_used_features(journal_t *journal, unsigned long compat,
2215                                  unsigned long ro, unsigned long incompat)
2216 {
2217         journal_superblock_t *sb;
2218
2219         if (!compat && !ro && !incompat)
2220                 return 1;
2221         /* Load journal superblock if it is not loaded yet. */
2222         if (journal->j_format_version == 0 &&
2223             journal_get_superblock(journal) != 0)
2224                 return 0;
2225         if (journal->j_format_version == 1)
2226                 return 0;
2227
2228         sb = journal->j_superblock;
2229
2230         if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
2231             ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
2232             ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
2233                 return 1;
2234
2235         return 0;
2236 }
2237
2238 /**
2239  * jbd2_journal_check_available_features() - Check feature set in journalling layer
2240  * @journal: Journal to check.
2241  * @compat: bitmask of compatible features
2242  * @ro: bitmask of features that force read-only mount
2243  * @incompat: bitmask of incompatible features
2244  *
2245  * Check whether the journaling code supports the use of
2246  * all of a given set of features on this journal.  Return true
2247  * (non-zero) if it can. */
2248
2249 int jbd2_journal_check_available_features(journal_t *journal, unsigned long compat,
2250                                       unsigned long ro, unsigned long incompat)
2251 {
2252         if (!compat && !ro && !incompat)
2253                 return 1;
2254
2255         /* We can support any known requested features iff the
2256          * superblock is in version 2.  Otherwise we fail to support any
2257          * extended sb features. */
2258
2259         if (journal->j_format_version != 2)
2260                 return 0;
2261
2262         if ((compat   & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
2263             (ro       & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro &&
2264             (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat)
2265                 return 1;
2266
2267         return 0;
2268 }
2269
2270 static int
2271 jbd2_journal_initialize_fast_commit(journal_t *journal)
2272 {
2273         journal_superblock_t *sb = journal->j_superblock;
2274         unsigned long long num_fc_blks;
2275
2276         num_fc_blks = jbd2_journal_get_num_fc_blks(sb);
2277         if (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS)
2278                 return -ENOSPC;
2279
2280         /* Are we called twice? */
2281         WARN_ON(journal->j_fc_wbuf != NULL);
2282         journal->j_fc_wbuf = kmalloc_array(num_fc_blks,
2283                                 sizeof(struct buffer_head *), GFP_KERNEL);
2284         if (!journal->j_fc_wbuf)
2285                 return -ENOMEM;
2286
2287         journal->j_fc_wbufsize = num_fc_blks;
2288         journal->j_fc_last = journal->j_last;
2289         journal->j_last = journal->j_fc_last - num_fc_blks;
2290         journal->j_fc_first = journal->j_last + 1;
2291         journal->j_fc_off = 0;
2292         journal->j_free = journal->j_last - journal->j_first;
2293         journal->j_max_transaction_buffers =
2294                 jbd2_journal_get_max_txn_bufs(journal);
2295
2296         return 0;
2297 }
2298
2299 /**
2300  * jbd2_journal_set_features() - Mark a given journal feature in the superblock
2301  * @journal: Journal to act on.
2302  * @compat: bitmask of compatible features
2303  * @ro: bitmask of features that force read-only mount
2304  * @incompat: bitmask of incompatible features
2305  *
2306  * Mark a given journal feature as present on the
2307  * superblock.  Returns true if the requested features could be set.
2308  *
2309  */
2310
2311 int jbd2_journal_set_features(journal_t *journal, unsigned long compat,
2312                           unsigned long ro, unsigned long incompat)
2313 {
2314 #define INCOMPAT_FEATURE_ON(f) \
2315                 ((incompat & (f)) && !(sb->s_feature_incompat & cpu_to_be32(f)))
2316 #define COMPAT_FEATURE_ON(f) \
2317                 ((compat & (f)) && !(sb->s_feature_compat & cpu_to_be32(f)))
2318         journal_superblock_t *sb;
2319
2320         if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
2321                 return 1;
2322
2323         if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
2324                 return 0;
2325
2326         /* If enabling v2 checksums, turn on v3 instead */
2327         if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V2) {
2328                 incompat &= ~JBD2_FEATURE_INCOMPAT_CSUM_V2;
2329                 incompat |= JBD2_FEATURE_INCOMPAT_CSUM_V3;
2330         }
2331
2332         /* Asking for checksumming v3 and v1?  Only give them v3. */
2333         if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V3 &&
2334             compat & JBD2_FEATURE_COMPAT_CHECKSUM)
2335                 compat &= ~JBD2_FEATURE_COMPAT_CHECKSUM;
2336
2337         jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
2338                   compat, ro, incompat);
2339
2340         sb = journal->j_superblock;
2341
2342         if (incompat & JBD2_FEATURE_INCOMPAT_FAST_COMMIT) {
2343                 if (jbd2_journal_initialize_fast_commit(journal)) {
2344                         pr_err("JBD2: Cannot enable fast commits.\n");
2345                         return 0;
2346                 }
2347         }
2348
2349         /* Load the checksum driver if necessary */
2350         if ((journal->j_chksum_driver == NULL) &&
2351             INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
2352                 journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
2353                 if (IS_ERR(journal->j_chksum_driver)) {
2354                         printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
2355                         journal->j_chksum_driver = NULL;
2356                         return 0;
2357                 }
2358                 /* Precompute checksum seed for all metadata */
2359                 journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
2360                                                    sizeof(sb->s_uuid));
2361         }
2362
2363         lock_buffer(journal->j_sb_buffer);
2364
2365         /* If enabling v3 checksums, update superblock */
2366         if (INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
2367                 sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
2368                 sb->s_feature_compat &=
2369                         ~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
2370         }
2371
2372         /* If enabling v1 checksums, downgrade superblock */
2373         if (COMPAT_FEATURE_ON(JBD2_FEATURE_COMPAT_CHECKSUM))
2374                 sb->s_feature_incompat &=
2375                         ~cpu_to_be32(JBD2_FEATURE_INCOMPAT_CSUM_V2 |
2376                                      JBD2_FEATURE_INCOMPAT_CSUM_V3);
2377
2378         sb->s_feature_compat    |= cpu_to_be32(compat);
2379         sb->s_feature_ro_compat |= cpu_to_be32(ro);
2380         sb->s_feature_incompat  |= cpu_to_be32(incompat);
2381         unlock_buffer(journal->j_sb_buffer);
2382         journal->j_revoke_records_per_block =
2383                                 journal_revoke_records_per_block(journal);
2384
2385         return 1;
2386 #undef COMPAT_FEATURE_ON
2387 #undef INCOMPAT_FEATURE_ON
2388 }
2389
2390 /*
2391  * jbd2_journal_clear_features() - Clear a given journal feature in the
2392  *                                  superblock
2393  * @journal: Journal to act on.
2394  * @compat: bitmask of compatible features
2395  * @ro: bitmask of features that force read-only mount
2396  * @incompat: bitmask of incompatible features
2397  *
2398  * Clear a given journal feature as present on the
2399  * superblock.
2400  */
2401 void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
2402                                 unsigned long ro, unsigned long incompat)
2403 {
2404         journal_superblock_t *sb;
2405
2406         jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
2407                   compat, ro, incompat);
2408
2409         sb = journal->j_superblock;
2410
2411         sb->s_feature_compat    &= ~cpu_to_be32(compat);
2412         sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
2413         sb->s_feature_incompat  &= ~cpu_to_be32(incompat);
2414         journal->j_revoke_records_per_block =
2415                                 journal_revoke_records_per_block(journal);
2416 }
2417 EXPORT_SYMBOL(jbd2_journal_clear_features);
2418
2419 /**
2420  * jbd2_journal_flush() - Flush journal
2421  * @journal: Journal to act on.
2422  * @flags: optional operation on the journal blocks after the flush (see below)
2423  *
2424  * Flush all data for a given journal to disk and empty the journal.
2425  * Filesystems can use this when remounting readonly to ensure that
2426  * recovery does not need to happen on remount. Optionally, a discard or zeroout
2427  * can be issued on the journal blocks after flushing.
2428  *
2429  * flags:
2430  *      JBD2_JOURNAL_FLUSH_DISCARD: issues discards for the journal blocks
2431  *      JBD2_JOURNAL_FLUSH_ZEROOUT: issues zeroouts for the journal blocks
2432  */
2433 int jbd2_journal_flush(journal_t *journal, unsigned int flags)
2434 {
2435         int err = 0;
2436         transaction_t *transaction = NULL;
2437
2438         write_lock(&journal->j_state_lock);
2439
2440         /* Force everything buffered to the log... */
2441         if (journal->j_running_transaction) {
2442                 transaction = journal->j_running_transaction;
2443                 __jbd2_log_start_commit(journal, transaction->t_tid);
2444         } else if (journal->j_committing_transaction)
2445                 transaction = journal->j_committing_transaction;
2446
2447         /* Wait for the log commit to complete... */
2448         if (transaction) {
2449                 tid_t tid = transaction->t_tid;
2450
2451                 write_unlock(&journal->j_state_lock);
2452                 jbd2_log_wait_commit(journal, tid);
2453         } else {
2454                 write_unlock(&journal->j_state_lock);
2455         }
2456
2457         /* ...and flush everything in the log out to disk. */
2458         spin_lock(&journal->j_list_lock);
2459         while (!err && journal->j_checkpoint_transactions != NULL) {
2460                 spin_unlock(&journal->j_list_lock);
2461                 mutex_lock_io(&journal->j_checkpoint_mutex);
2462                 err = jbd2_log_do_checkpoint(journal);
2463                 mutex_unlock(&journal->j_checkpoint_mutex);
2464                 spin_lock(&journal->j_list_lock);
2465         }
2466         spin_unlock(&journal->j_list_lock);
2467
2468         if (is_journal_aborted(journal))
2469                 return -EIO;
2470
2471         mutex_lock_io(&journal->j_checkpoint_mutex);
2472         if (!err) {
2473                 err = jbd2_cleanup_journal_tail(journal);
2474                 if (err < 0) {
2475                         mutex_unlock(&journal->j_checkpoint_mutex);
2476                         goto out;
2477                 }
2478                 err = 0;
2479         }
2480
2481         /* Finally, mark the journal as really needing no recovery.
2482          * This sets s_start==0 in the underlying superblock, which is
2483          * the magic code for a fully-recovered superblock.  Any future
2484          * commits of data to the journal will restore the current
2485          * s_start value. */
2486         jbd2_mark_journal_empty(journal, REQ_SYNC | REQ_FUA);
2487
2488         if (flags)
2489                 err = __jbd2_journal_erase(journal, flags);
2490
2491         mutex_unlock(&journal->j_checkpoint_mutex);
2492         write_lock(&journal->j_state_lock);
2493         J_ASSERT(!journal->j_running_transaction);
2494         J_ASSERT(!journal->j_committing_transaction);
2495         J_ASSERT(!journal->j_checkpoint_transactions);
2496         J_ASSERT(journal->j_head == journal->j_tail);
2497         J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
2498         write_unlock(&journal->j_state_lock);
2499 out:
2500         return err;
2501 }
2502
2503 /**
2504  * jbd2_journal_wipe() - Wipe journal contents
2505  * @journal: Journal to act on.
2506  * @write: flag (see below)
2507  *
2508  * Wipe out all of the contents of a journal, safely.  This will produce
2509  * a warning if the journal contains any valid recovery information.
2510  * Must be called between journal_init_*() and jbd2_journal_load().
2511  *
2512  * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
2513  * we merely suppress recovery.
2514  */
2515
2516 int jbd2_journal_wipe(journal_t *journal, int write)
2517 {
2518         int err = 0;
2519
2520         J_ASSERT (!(journal->j_flags & JBD2_LOADED));
2521
2522         err = load_superblock(journal);
2523         if (err)
2524                 return err;
2525
2526         if (!journal->j_tail)
2527                 goto no_recovery;
2528
2529         printk(KERN_WARNING "JBD2: %s recovery information on journal\n",
2530                 write ? "Clearing" : "Ignoring");
2531
2532         err = jbd2_journal_skip_recovery(journal);
2533         if (write) {
2534                 /* Lock to make assertions happy... */
2535                 mutex_lock_io(&journal->j_checkpoint_mutex);
2536                 jbd2_mark_journal_empty(journal, REQ_SYNC | REQ_FUA);
2537                 mutex_unlock(&journal->j_checkpoint_mutex);
2538         }
2539
2540  no_recovery:
2541         return err;
2542 }
2543
2544 /**
2545  * jbd2_journal_abort () - Shutdown the journal immediately.
2546  * @journal: the journal to shutdown.
2547  * @errno:   an error number to record in the journal indicating
2548  *           the reason for the shutdown.
2549  *
2550  * Perform a complete, immediate shutdown of the ENTIRE
2551  * journal (not of a single transaction).  This operation cannot be
2552  * undone without closing and reopening the journal.
2553  *
2554  * The jbd2_journal_abort function is intended to support higher level error
2555  * recovery mechanisms such as the ext2/ext3 remount-readonly error
2556  * mode.
2557  *
2558  * Journal abort has very specific semantics.  Any existing dirty,
2559  * unjournaled buffers in the main filesystem will still be written to
2560  * disk by bdflush, but the journaling mechanism will be suspended
2561  * immediately and no further transaction commits will be honoured.
2562  *
2563  * Any dirty, journaled buffers will be written back to disk without
2564  * hitting the journal.  Atomicity cannot be guaranteed on an aborted
2565  * filesystem, but we _do_ attempt to leave as much data as possible
2566  * behind for fsck to use for cleanup.
2567  *
2568  * Any attempt to get a new transaction handle on a journal which is in
2569  * ABORT state will just result in an -EROFS error return.  A
2570  * jbd2_journal_stop on an existing handle will return -EIO if we have
2571  * entered abort state during the update.
2572  *
2573  * Recursive transactions are not disturbed by journal abort until the
2574  * final jbd2_journal_stop, which will receive the -EIO error.
2575  *
2576  * Finally, the jbd2_journal_abort call allows the caller to supply an errno
2577  * which will be recorded (if possible) in the journal superblock.  This
2578  * allows a client to record failure conditions in the middle of a
2579  * transaction without having to complete the transaction to record the
2580  * failure to disk.  ext3_error, for example, now uses this
2581  * functionality.
2582  *
2583  */
2584
2585 void jbd2_journal_abort(journal_t *journal, int errno)
2586 {
2587         transaction_t *transaction;
2588
2589         /*
2590          * Lock the aborting procedure until everything is done, this avoid
2591          * races between filesystem's error handling flow (e.g. ext4_abort()),
2592          * ensure panic after the error info is written into journal's
2593          * superblock.
2594          */
2595         mutex_lock(&journal->j_abort_mutex);
2596         /*
2597          * ESHUTDOWN always takes precedence because a file system check
2598          * caused by any other journal abort error is not required after
2599          * a shutdown triggered.
2600          */
2601         write_lock(&journal->j_state_lock);
2602         if (journal->j_flags & JBD2_ABORT) {
2603                 int old_errno = journal->j_errno;
2604
2605                 write_unlock(&journal->j_state_lock);
2606                 if (old_errno != -ESHUTDOWN && errno == -ESHUTDOWN) {
2607                         journal->j_errno = errno;
2608                         jbd2_journal_update_sb_errno(journal);
2609                 }
2610                 mutex_unlock(&journal->j_abort_mutex);
2611                 return;
2612         }
2613
2614         /*
2615          * Mark the abort as occurred and start current running transaction
2616          * to release all journaled buffer.
2617          */
2618         pr_err("Aborting journal on device %s.\n", journal->j_devname);
2619
2620         journal->j_flags |= JBD2_ABORT;
2621         journal->j_errno = errno;
2622         transaction = journal->j_running_transaction;
2623         if (transaction)
2624                 __jbd2_log_start_commit(journal, transaction->t_tid);
2625         write_unlock(&journal->j_state_lock);
2626
2627         /*
2628          * Record errno to the journal super block, so that fsck and jbd2
2629          * layer could realise that a filesystem check is needed.
2630          */
2631         jbd2_journal_update_sb_errno(journal);
2632         mutex_unlock(&journal->j_abort_mutex);
2633 }
2634
2635 /**
2636  * jbd2_journal_errno() - returns the journal's error state.
2637  * @journal: journal to examine.
2638  *
2639  * This is the errno number set with jbd2_journal_abort(), the last
2640  * time the journal was mounted - if the journal was stopped
2641  * without calling abort this will be 0.
2642  *
2643  * If the journal has been aborted on this mount time -EROFS will
2644  * be returned.
2645  */
2646 int jbd2_journal_errno(journal_t *journal)
2647 {
2648         int err;
2649
2650         read_lock(&journal->j_state_lock);
2651         if (journal->j_flags & JBD2_ABORT)
2652                 err = -EROFS;
2653         else
2654                 err = journal->j_errno;
2655         read_unlock(&journal->j_state_lock);
2656         return err;
2657 }
2658
2659 /**
2660  * jbd2_journal_clear_err() - clears the journal's error state
2661  * @journal: journal to act on.
2662  *
2663  * An error must be cleared or acked to take a FS out of readonly
2664  * mode.
2665  */
2666 int jbd2_journal_clear_err(journal_t *journal)
2667 {
2668         int err = 0;
2669
2670         write_lock(&journal->j_state_lock);
2671         if (journal->j_flags & JBD2_ABORT)
2672                 err = -EROFS;
2673         else
2674                 journal->j_errno = 0;
2675         write_unlock(&journal->j_state_lock);
2676         return err;
2677 }
2678
2679 /**
2680  * jbd2_journal_ack_err() - Ack journal err.
2681  * @journal: journal to act on.
2682  *
2683  * An error must be cleared or acked to take a FS out of readonly
2684  * mode.
2685  */
2686 void jbd2_journal_ack_err(journal_t *journal)
2687 {
2688         write_lock(&journal->j_state_lock);
2689         if (journal->j_errno)
2690                 journal->j_flags |= JBD2_ACK_ERR;
2691         write_unlock(&journal->j_state_lock);
2692 }
2693
2694 int jbd2_journal_blocks_per_page(struct inode *inode)
2695 {
2696         return 1 << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
2697 }
2698
2699 /*
2700  * helper functions to deal with 32 or 64bit block numbers.
2701  */
2702 size_t journal_tag_bytes(journal_t *journal)
2703 {
2704         size_t sz;
2705
2706         if (jbd2_has_feature_csum3(journal))
2707                 return sizeof(journal_block_tag3_t);
2708
2709         sz = sizeof(journal_block_tag_t);
2710
2711         if (jbd2_has_feature_csum2(journal))
2712                 sz += sizeof(__u16);
2713
2714         if (jbd2_has_feature_64bit(journal))
2715                 return sz;
2716         else
2717                 return sz - sizeof(__u32);
2718 }
2719
2720 /*
2721  * JBD memory management
2722  *
2723  * These functions are used to allocate block-sized chunks of memory
2724  * used for making copies of buffer_head data.  Very often it will be
2725  * page-sized chunks of data, but sometimes it will be in
2726  * sub-page-size chunks.  (For example, 16k pages on Power systems
2727  * with a 4k block file system.)  For blocks smaller than a page, we
2728  * use a SLAB allocator.  There are slab caches for each block size,
2729  * which are allocated at mount time, if necessary, and we only free
2730  * (all of) the slab caches when/if the jbd2 module is unloaded.  For
2731  * this reason we don't need to a mutex to protect access to
2732  * jbd2_slab[] allocating or releasing memory; only in
2733  * jbd2_journal_create_slab().
2734  */
2735 #define JBD2_MAX_SLABS 8
2736 static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS];
2737
2738 static const char *jbd2_slab_names[JBD2_MAX_SLABS] = {
2739         "jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k",
2740         "jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k"
2741 };
2742
2743
2744 static void jbd2_journal_destroy_slabs(void)
2745 {
2746         int i;
2747
2748         for (i = 0; i < JBD2_MAX_SLABS; i++) {
2749                 kmem_cache_destroy(jbd2_slab[i]);
2750                 jbd2_slab[i] = NULL;
2751         }
2752 }
2753
2754 static int jbd2_journal_create_slab(size_t size)
2755 {
2756         static DEFINE_MUTEX(jbd2_slab_create_mutex);
2757         int i = order_base_2(size) - 10;
2758         size_t slab_size;
2759
2760         if (size == PAGE_SIZE)
2761                 return 0;
2762
2763         if (i >= JBD2_MAX_SLABS)
2764                 return -EINVAL;
2765
2766         if (unlikely(i < 0))
2767                 i = 0;
2768         mutex_lock(&jbd2_slab_create_mutex);
2769         if (jbd2_slab[i]) {
2770                 mutex_unlock(&jbd2_slab_create_mutex);
2771                 return 0;       /* Already created */
2772         }
2773
2774         slab_size = 1 << (i+10);
2775         jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size,
2776                                          slab_size, 0, NULL);
2777         mutex_unlock(&jbd2_slab_create_mutex);
2778         if (!jbd2_slab[i]) {
2779                 printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n");
2780                 return -ENOMEM;
2781         }
2782         return 0;
2783 }
2784
2785 static struct kmem_cache *get_slab(size_t size)
2786 {
2787         int i = order_base_2(size) - 10;
2788
2789         BUG_ON(i >= JBD2_MAX_SLABS);
2790         if (unlikely(i < 0))
2791                 i = 0;
2792         BUG_ON(jbd2_slab[i] == NULL);
2793         return jbd2_slab[i];
2794 }
2795
2796 void *jbd2_alloc(size_t size, gfp_t flags)
2797 {
2798         void *ptr;
2799
2800         BUG_ON(size & (size-1)); /* Must be a power of 2 */
2801
2802         if (size < PAGE_SIZE)
2803                 ptr = kmem_cache_alloc(get_slab(size), flags);
2804         else
2805                 ptr = (void *)__get_free_pages(flags, get_order(size));
2806
2807         /* Check alignment; SLUB has gotten this wrong in the past,
2808          * and this can lead to user data corruption! */
2809         BUG_ON(((unsigned long) ptr) & (size-1));
2810
2811         return ptr;
2812 }
2813
2814 void jbd2_free(void *ptr, size_t size)
2815 {
2816         if (size < PAGE_SIZE)
2817                 kmem_cache_free(get_slab(size), ptr);
2818         else
2819                 free_pages((unsigned long)ptr, get_order(size));
2820 };
2821
2822 /*
2823  * Journal_head storage management
2824  */
2825 static struct kmem_cache *jbd2_journal_head_cache;
2826 #ifdef CONFIG_JBD2_DEBUG
2827 static atomic_t nr_journal_heads = ATOMIC_INIT(0);
2828 #endif
2829
2830 static int __init jbd2_journal_init_journal_head_cache(void)
2831 {
2832         J_ASSERT(!jbd2_journal_head_cache);
2833         jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
2834                                 sizeof(struct journal_head),
2835                                 0,              /* offset */
2836                                 SLAB_TEMPORARY | SLAB_TYPESAFE_BY_RCU,
2837                                 NULL);          /* ctor */
2838         if (!jbd2_journal_head_cache) {
2839                 printk(KERN_EMERG "JBD2: no memory for journal_head cache\n");
2840                 return -ENOMEM;
2841         }
2842         return 0;
2843 }
2844
2845 static void jbd2_journal_destroy_journal_head_cache(void)
2846 {
2847         kmem_cache_destroy(jbd2_journal_head_cache);
2848         jbd2_journal_head_cache = NULL;
2849 }
2850
2851 /*
2852  * journal_head splicing and dicing
2853  */
2854 static struct journal_head *journal_alloc_journal_head(void)
2855 {
2856         struct journal_head *ret;
2857
2858 #ifdef CONFIG_JBD2_DEBUG
2859         atomic_inc(&nr_journal_heads);
2860 #endif
2861         ret = kmem_cache_zalloc(jbd2_journal_head_cache, GFP_NOFS);
2862         if (!ret) {
2863                 jbd_debug(1, "out of memory for journal_head\n");
2864                 pr_notice_ratelimited("ENOMEM in %s, retrying.\n", __func__);
2865                 ret = kmem_cache_zalloc(jbd2_journal_head_cache,
2866                                 GFP_NOFS | __GFP_NOFAIL);
2867         }
2868         if (ret)
2869                 spin_lock_init(&ret->b_state_lock);
2870         return ret;
2871 }
2872
2873 static void journal_free_journal_head(struct journal_head *jh)
2874 {
2875 #ifdef CONFIG_JBD2_DEBUG
2876         atomic_dec(&nr_journal_heads);
2877         memset(jh, JBD2_POISON_FREE, sizeof(*jh));
2878 #endif
2879         kmem_cache_free(jbd2_journal_head_cache, jh);
2880 }
2881
2882 /*
2883  * A journal_head is attached to a buffer_head whenever JBD has an
2884  * interest in the buffer.
2885  *
2886  * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
2887  * is set.  This bit is tested in core kernel code where we need to take
2888  * JBD-specific actions.  Testing the zeroness of ->b_private is not reliable
2889  * there.
2890  *
2891  * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
2892  *
2893  * When a buffer has its BH_JBD bit set it is immune from being released by
2894  * core kernel code, mainly via ->b_count.
2895  *
2896  * A journal_head is detached from its buffer_head when the journal_head's
2897  * b_jcount reaches zero. Running transaction (b_transaction) and checkpoint
2898  * transaction (b_cp_transaction) hold their references to b_jcount.
2899  *
2900  * Various places in the kernel want to attach a journal_head to a buffer_head
2901  * _before_ attaching the journal_head to a transaction.  To protect the
2902  * journal_head in this situation, jbd2_journal_add_journal_head elevates the
2903  * journal_head's b_jcount refcount by one.  The caller must call
2904  * jbd2_journal_put_journal_head() to undo this.
2905  *
2906  * So the typical usage would be:
2907  *
2908  *      (Attach a journal_head if needed.  Increments b_jcount)
2909  *      struct journal_head *jh = jbd2_journal_add_journal_head(bh);
2910  *      ...
2911  *      (Get another reference for transaction)
2912  *      jbd2_journal_grab_journal_head(bh);
2913  *      jh->b_transaction = xxx;
2914  *      (Put original reference)
2915  *      jbd2_journal_put_journal_head(jh);
2916  */
2917
2918 /*
2919  * Give a buffer_head a journal_head.
2920  *
2921  * May sleep.
2922  */
2923 struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
2924 {
2925         struct journal_head *jh;
2926         struct journal_head *new_jh = NULL;
2927
2928 repeat:
2929         if (!buffer_jbd(bh))
2930                 new_jh = journal_alloc_journal_head();
2931
2932         jbd_lock_bh_journal_head(bh);
2933         if (buffer_jbd(bh)) {
2934                 jh = bh2jh(bh);
2935         } else {
2936                 J_ASSERT_BH(bh,
2937                         (atomic_read(&bh->b_count) > 0) ||
2938                         (bh->b_page && bh->b_page->mapping));
2939
2940                 if (!new_jh) {
2941                         jbd_unlock_bh_journal_head(bh);
2942                         goto repeat;
2943                 }
2944
2945                 jh = new_jh;
2946                 new_jh = NULL;          /* We consumed it */
2947                 set_buffer_jbd(bh);
2948                 bh->b_private = jh;
2949                 jh->b_bh = bh;
2950                 get_bh(bh);
2951                 BUFFER_TRACE(bh, "added journal_head");
2952         }
2953         jh->b_jcount++;
2954         jbd_unlock_bh_journal_head(bh);
2955         if (new_jh)
2956                 journal_free_journal_head(new_jh);
2957         return bh->b_private;
2958 }
2959
2960 /*
2961  * Grab a ref against this buffer_head's journal_head.  If it ended up not
2962  * having a journal_head, return NULL
2963  */
2964 struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh)
2965 {
2966         struct journal_head *jh = NULL;
2967
2968         jbd_lock_bh_journal_head(bh);
2969         if (buffer_jbd(bh)) {
2970                 jh = bh2jh(bh);
2971                 jh->b_jcount++;
2972         }
2973         jbd_unlock_bh_journal_head(bh);
2974         return jh;
2975 }
2976 EXPORT_SYMBOL(jbd2_journal_grab_journal_head);
2977
2978 static void __journal_remove_journal_head(struct buffer_head *bh)
2979 {
2980         struct journal_head *jh = bh2jh(bh);
2981
2982         J_ASSERT_JH(jh, jh->b_transaction == NULL);
2983         J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
2984         J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
2985         J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
2986         J_ASSERT_BH(bh, buffer_jbd(bh));
2987         J_ASSERT_BH(bh, jh2bh(jh) == bh);
2988         BUFFER_TRACE(bh, "remove journal_head");
2989
2990         /* Unlink before dropping the lock */
2991         bh->b_private = NULL;
2992         jh->b_bh = NULL;        /* debug, really */
2993         clear_buffer_jbd(bh);
2994 }
2995
2996 static void journal_release_journal_head(struct journal_head *jh, size_t b_size)
2997 {
2998         if (jh->b_frozen_data) {
2999                 printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
3000                 jbd2_free(jh->b_frozen_data, b_size);
3001         }
3002         if (jh->b_committed_data) {
3003                 printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
3004                 jbd2_free(jh->b_committed_data, b_size);
3005         }
3006         journal_free_journal_head(jh);
3007 }
3008
3009 /*
3010  * Drop a reference on the passed journal_head.  If it fell to zero then
3011  * release the journal_head from the buffer_head.
3012  */
3013 void jbd2_journal_put_journal_head(struct journal_head *jh)
3014 {
3015         struct buffer_head *bh = jh2bh(jh);
3016
3017         jbd_lock_bh_journal_head(bh);
3018         J_ASSERT_JH(jh, jh->b_jcount > 0);
3019         --jh->b_jcount;
3020         if (!jh->b_jcount) {
3021                 __journal_remove_journal_head(bh);
3022                 jbd_unlock_bh_journal_head(bh);
3023                 journal_release_journal_head(jh, bh->b_size);
3024                 __brelse(bh);
3025         } else {
3026                 jbd_unlock_bh_journal_head(bh);
3027         }
3028 }
3029 EXPORT_SYMBOL(jbd2_journal_put_journal_head);
3030
3031 /*
3032  * Initialize jbd inode head
3033  */
3034 void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode)
3035 {
3036         jinode->i_transaction = NULL;
3037         jinode->i_next_transaction = NULL;
3038         jinode->i_vfs_inode = inode;
3039         jinode->i_flags = 0;
3040         jinode->i_dirty_start = 0;
3041         jinode->i_dirty_end = 0;
3042         INIT_LIST_HEAD(&jinode->i_list);
3043 }
3044
3045 /*
3046  * Function to be called before we start removing inode from memory (i.e.,
3047  * clear_inode() is a fine place to be called from). It removes inode from
3048  * transaction's lists.
3049  */
3050 void jbd2_journal_release_jbd_inode(journal_t *journal,
3051                                     struct jbd2_inode *jinode)
3052 {
3053         if (!journal)
3054                 return;
3055 restart:
3056         spin_lock(&journal->j_list_lock);
3057         /* Is commit writing out inode - we have to wait */
3058         if (jinode->i_flags & JI_COMMIT_RUNNING) {
3059                 wait_queue_head_t *wq;
3060                 DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
3061                 wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
3062                 prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
3063                 spin_unlock(&journal->j_list_lock);
3064                 schedule();
3065                 finish_wait(wq, &wait.wq_entry);
3066                 goto restart;
3067         }
3068
3069         if (jinode->i_transaction) {
3070                 list_del(&jinode->i_list);
3071                 jinode->i_transaction = NULL;
3072         }
3073         spin_unlock(&journal->j_list_lock);
3074 }
3075
3076
3077 #ifdef CONFIG_PROC_FS
3078
3079 #define JBD2_STATS_PROC_NAME "fs/jbd2"
3080
3081 static void __init jbd2_create_jbd_stats_proc_entry(void)
3082 {
3083         proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL);
3084 }
3085
3086 static void __exit jbd2_remove_jbd_stats_proc_entry(void)
3087 {
3088         if (proc_jbd2_stats)
3089                 remove_proc_entry(JBD2_STATS_PROC_NAME, NULL);
3090 }
3091
3092 #else
3093
3094 #define jbd2_create_jbd_stats_proc_entry() do {} while (0)
3095 #define jbd2_remove_jbd_stats_proc_entry() do {} while (0)
3096
3097 #endif
3098
3099 struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
3100
3101 static int __init jbd2_journal_init_inode_cache(void)
3102 {
3103         J_ASSERT(!jbd2_inode_cache);
3104         jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0);
3105         if (!jbd2_inode_cache) {
3106                 pr_emerg("JBD2: failed to create inode cache\n");
3107                 return -ENOMEM;
3108         }
3109         return 0;
3110 }
3111
3112 static int __init jbd2_journal_init_handle_cache(void)
3113 {
3114         J_ASSERT(!jbd2_handle_cache);
3115         jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
3116         if (!jbd2_handle_cache) {
3117                 printk(KERN_EMERG "JBD2: failed to create handle cache\n");
3118                 return -ENOMEM;
3119         }
3120         return 0;
3121 }
3122
3123 static void jbd2_journal_destroy_inode_cache(void)
3124 {
3125         kmem_cache_destroy(jbd2_inode_cache);
3126         jbd2_inode_cache = NULL;
3127 }
3128
3129 static void jbd2_journal_destroy_handle_cache(void)
3130 {
3131         kmem_cache_destroy(jbd2_handle_cache);
3132         jbd2_handle_cache = NULL;
3133 }
3134
3135 /*
3136  * Module startup and shutdown
3137  */
3138
3139 static int __init journal_init_caches(void)
3140 {
3141         int ret;
3142
3143         ret = jbd2_journal_init_revoke_record_cache();
3144         if (ret == 0)
3145                 ret = jbd2_journal_init_revoke_table_cache();
3146         if (ret == 0)
3147                 ret = jbd2_journal_init_journal_head_cache();
3148         if (ret == 0)
3149                 ret = jbd2_journal_init_handle_cache();
3150         if (ret == 0)
3151                 ret = jbd2_journal_init_inode_cache();
3152         if (ret == 0)
3153                 ret = jbd2_journal_init_transaction_cache();
3154         return ret;
3155 }
3156
3157 static void jbd2_journal_destroy_caches(void)
3158 {
3159         jbd2_journal_destroy_revoke_record_cache();
3160         jbd2_journal_destroy_revoke_table_cache();
3161         jbd2_journal_destroy_journal_head_cache();
3162         jbd2_journal_destroy_handle_cache();
3163         jbd2_journal_destroy_inode_cache();
3164         jbd2_journal_destroy_transaction_cache();
3165         jbd2_journal_destroy_slabs();
3166 }
3167
3168 static int __init journal_init(void)
3169 {
3170         int ret;
3171
3172         BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
3173
3174         ret = journal_init_caches();
3175         if (ret == 0) {
3176                 jbd2_create_jbd_stats_proc_entry();
3177         } else {
3178                 jbd2_journal_destroy_caches();
3179         }
3180         return ret;
3181 }
3182
3183 static void __exit journal_exit(void)
3184 {
3185 #ifdef CONFIG_JBD2_DEBUG
3186         int n = atomic_read(&nr_journal_heads);
3187         if (n)
3188                 printk(KERN_ERR "JBD2: leaked %d journal_heads!\n", n);
3189 #endif
3190         jbd2_remove_jbd_stats_proc_entry();
3191         jbd2_journal_destroy_caches();
3192 }
3193
3194 MODULE_LICENSE("GPL");
3195 module_init(journal_init);
3196 module_exit(journal_exit);
3197