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_invalidatepage);
  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
 761         return 0;
 762 }
 763 EXPORT_SYMBOL(jbd2_fc_begin_commit);
 764
 765 /*
 766  * Stop a fast commit. If fallback is set, this function starts commit of
 767  * TID tid before any other fast commit can start.
 768  */
 769 static int __jbd2_fc_end_commit(journal_t *journal, tid_t tid, bool fallback)
 770 {
 771         if (journal->j_fc_cleanup_callback)
 772                 journal->j_fc_cleanup_callback(journal, 0);
 773         write_lock(&journal->j_state_lock);
 774         journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
 775         if (fallback)
 776                 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
 777         write_unlock(&journal->j_state_lock);
 778         wake_up(&journal->j_fc_wait);
 779         if (fallback)
 780                 return jbd2_complete_transaction(journal, tid);
 781         return 0;
 782 }
 783
 784 int jbd2_fc_end_commit(journal_t *journal)
 785 {
 786         return __jbd2_fc_end_commit(journal, 0, false);
 787 }
 788 EXPORT_SYMBOL(jbd2_fc_end_commit);
 789
 790 int jbd2_fc_end_commit_fallback(journal_t *journal)
 791 {
 792         tid_t tid;
 793
 794         read_lock(&journal->j_state_lock);
 795         tid = journal->j_running_transaction ?
 796                 journal->j_running_transaction->t_tid : 0;
 797         read_unlock(&journal->j_state_lock);
 798         return __jbd2_fc_end_commit(journal, tid, true);
 799 }
 800 EXPORT_SYMBOL(jbd2_fc_end_commit_fallback);
 801
 802 /* Return 1 when transaction with given tid has already committed. */
 803 int jbd2_transaction_committed(journal_t *journal, tid_t tid)
 804 {
 805         int ret = 1;
 806
 807         read_lock(&journal->j_state_lock);
 808         if (journal->j_running_transaction &&
 809             journal->j_running_transaction->t_tid == tid)
 810                 ret = 0;
 811         if (journal->j_committing_transaction &&
 812             journal->j_committing_transaction->t_tid == tid)
 813                 ret = 0;
 814         read_unlock(&journal->j_state_lock);
 815         return ret;
 816 }
 817 EXPORT_SYMBOL(jbd2_transaction_committed);
 818
 819 /*
 820  * When this function returns the transaction corresponding to tid
 821  * will be completed.  If the transaction has currently running, start
 822  * committing that transaction before waiting for it to complete.  If
 823  * the transaction id is stale, it is by definition already completed,
 824  * so just return SUCCESS.
 825  */
 826 int jbd2_complete_transaction(journal_t *journal, tid_t tid)
 827 {
 828         int     need_to_wait = 1;
 829
 830         read_lock(&journal->j_state_lock);
 831         if (journal->j_running_transaction &&
 832             journal->j_running_transaction->t_tid == tid) {
 833                 if (journal->j_commit_request != tid) {
 834                         /* transaction not yet started, so request it */
 835                         read_unlock(&journal->j_state_lock);
 836                         jbd2_log_start_commit(journal, tid);
 837                         goto wait_commit;
 838                 }
 839         } else if (!(journal->j_committing_transaction &&
 840                      journal->j_committing_transaction->t_tid == tid))
 841                 need_to_wait = 0;
 842         read_unlock(&journal->j_state_lock);
 843         if (!need_to_wait)
 844                 return 0;
 845 wait_commit:
 846         return jbd2_log_wait_commit(journal, tid);
 847 }
 848 EXPORT_SYMBOL(jbd2_complete_transaction);
 849
 850 /*
 851  * Log buffer allocation routines:
 852  */
 853
 854 int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
 855 {
 856         unsigned long blocknr;
 857
 858         write_lock(&journal->j_state_lock);
 859         J_ASSERT(journal->j_free > 1);
 860
 861         blocknr = journal->j_head;
 862         journal->j_head++;
 863         journal->j_free--;
 864         if (journal->j_head == journal->j_last)
 865                 journal->j_head = journal->j_first;
 866         write_unlock(&journal->j_state_lock);
 867         return jbd2_journal_bmap(journal, blocknr, retp);
 868 }
 869
 870 /* Map one fast commit buffer for use by the file system */
 871 int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out)
 872 {
 873         unsigned long long pblock;
 874         unsigned long blocknr;
 875         int ret = 0;
 876         struct buffer_head *bh;
 877         int fc_off;
 878
 879         *bh_out = NULL;
 880
 881         if (journal->j_fc_off + journal->j_fc_first < journal->j_fc_last) {
 882                 fc_off = journal->j_fc_off;
 883                 blocknr = journal->j_fc_first + fc_off;
 884                 journal->j_fc_off++;
 885         } else {
 886                 ret = -EINVAL;
 887         }
 888
 889         if (ret)
 890                 return ret;
 891
 892         ret = jbd2_journal_bmap(journal, blocknr, &pblock);
 893         if (ret)
 894                 return ret;
 895
 896         bh = __getblk(journal->j_dev, pblock, journal->j_blocksize);
 897         if (!bh)
 898                 return -ENOMEM;
 899
 900
 901         journal->j_fc_wbuf[fc_off] = bh;
 902
 903         *bh_out = bh;
 904
 905         return 0;
 906 }
 907 EXPORT_SYMBOL(jbd2_fc_get_buf);
 908
 909 /*
 910  * Wait on fast commit buffers that were allocated by jbd2_fc_get_buf
 911  * for completion.
 912  */
 913 int jbd2_fc_wait_bufs(journal_t *journal, int num_blks)
 914 {
 915         struct buffer_head *bh;
 916         int i, j_fc_off;
 917
 918         j_fc_off = journal->j_fc_off;
 919
 920         /*
 921          * Wait in reverse order to minimize chances of us being woken up before
 922          * all IOs have completed
 923          */
 924         for (i = j_fc_off - 1; i >= j_fc_off - num_blks; i--) {
 925                 bh = journal->j_fc_wbuf[i];
 926                 wait_on_buffer(bh);
 927                 put_bh(bh);
 928                 journal->j_fc_wbuf[i] = NULL;
 929                 if (unlikely(!buffer_uptodate(bh)))
 930                         return -EIO;
 931         }
 932
 933         return 0;
 934 }
 935 EXPORT_SYMBOL(jbd2_fc_wait_bufs);
 936
 937 int jbd2_fc_release_bufs(journal_t *journal)
 938 {
 939         struct buffer_head *bh;
 940         int i, j_fc_off;
 941
 942         j_fc_off = journal->j_fc_off;
 943
 944         for (i = j_fc_off - 1; i >= 0; i--) {
 945                 bh = journal->j_fc_wbuf[i];
 946                 if (!bh)
 947                         break;
 948                 put_bh(bh);
 949                 journal->j_fc_wbuf[i] = NULL;
 950         }
 951
 952         return 0;
 953 }
 954 EXPORT_SYMBOL(jbd2_fc_release_bufs);
 955
 956 /*
 957  * Conversion of logical to physical block numbers for the journal
 958  *
 959  * On external journals the journal blocks are identity-mapped, so
 960  * this is a no-op.  If needed, we can use j_blk_offset - everything is
 961  * ready.
 962  */
 963 int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
 964                  unsigned long long *retp)
 965 {
 966         int err = 0;
 967         unsigned long long ret;
 968         sector_t block = 0;
 969
 970         if (journal->j_inode) {
 971                 block = blocknr;
 972                 ret = bmap(journal->j_inode, &block);
 973
 974                 if (ret || !block) {
 975                         printk(KERN_ALERT "%s: journal block not found "
 976                                         "at offset %lu on %s\n",
 977                                __func__, blocknr, journal->j_devname);
 978                         err = -EIO;
 979                         jbd2_journal_abort(journal, err);
 980                 } else {
 981                         *retp = block;
 982                 }
 983
 984         } else {
 985                 *retp = blocknr; /* +journal->j_blk_offset */
 986         }
 987         return err;
 988 }
 989
 990 /*
 991  * We play buffer_head aliasing tricks to write data/metadata blocks to
 992  * the journal without copying their contents, but for journal
 993  * descriptor blocks we do need to generate bona fide buffers.
 994  *
 995  * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
 996  * the buffer's contents they really should run flush_dcache_page(bh->b_page).
 997  * But we don't bother doing that, so there will be coherency problems with
 998  * mmaps of blockdevs which hold live JBD-controlled filesystems.
 999  */
1000 struct buffer_head *
1001 jbd2_journal_get_descriptor_buffer(transaction_t *transaction, int type)
1002 {
1003         journal_t *journal = transaction->t_journal;
1004         struct buffer_head *bh;
1005         unsigned long long blocknr;
1006         journal_header_t *header;
1007         int err;
1008
1009         err = jbd2_journal_next_log_block(journal, &blocknr);
1010
1011         if (err)
1012                 return NULL;
1013
1014         bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
1015         if (!bh)
1016                 return NULL;
1017         atomic_dec(&transaction->t_outstanding_credits);
1018         lock_buffer(bh);
1019         memset(bh->b_data, 0, journal->j_blocksize);
1020         header = (journal_header_t *)bh->b_data;
1021         header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
1022         header->h_blocktype = cpu_to_be32(type);
1023         header->h_sequence = cpu_to_be32(transaction->t_tid);
1024         set_buffer_uptodate(bh);
1025         unlock_buffer(bh);
1026         BUFFER_TRACE(bh, "return this buffer");
1027         return bh;
1028 }
1029
1030 void jbd2_descriptor_block_csum_set(journal_t *j, struct buffer_head *bh)
1031 {
1032         struct jbd2_journal_block_tail *tail;
1033         __u32 csum;
1034
1035         if (!jbd2_journal_has_csum_v2or3(j))
1036                 return;
1037
1038         tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize -
1039                         sizeof(struct jbd2_journal_block_tail));
1040         tail->t_checksum = 0;
1041         csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
1042         tail->t_checksum = cpu_to_be32(csum);
1043 }
1044
1045 /*
1046  * Return tid of the oldest transaction in the journal and block in the journal
1047  * where the transaction starts.
1048  *
1049  * If the journal is now empty, return which will be the next transaction ID
1050  * we will write and where will that transaction start.
1051  *
1052  * The return value is 0 if journal tail cannot be pushed any further, 1 if
1053  * it can.
1054  */
1055 int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
1056                               unsigned long *block)
1057 {
1058         transaction_t *transaction;
1059         int ret;
1060
1061         read_lock(&journal->j_state_lock);
1062         spin_lock(&journal->j_list_lock);
1063         transaction = journal->j_checkpoint_transactions;
1064         if (transaction) {
1065                 *tid = transaction->t_tid;
1066                 *block = transaction->t_log_start;
1067         } else if ((transaction = journal->j_committing_transaction) != NULL) {
1068                 *tid = transaction->t_tid;
1069                 *block = transaction->t_log_start;
1070         } else if ((transaction = journal->j_running_transaction) != NULL) {
1071                 *tid = transaction->t_tid;
1072                 *block = journal->j_head;
1073         } else {
1074                 *tid = journal->j_transaction_sequence;
1075                 *block = journal->j_head;
1076         }
1077         ret = tid_gt(*tid, journal->j_tail_sequence);
1078         spin_unlock(&journal->j_list_lock);
1079         read_unlock(&journal->j_state_lock);
1080
1081         return ret;
1082 }
1083
1084 /*
1085  * Update information in journal structure and in on disk journal superblock
1086  * about log tail. This function does not check whether information passed in
1087  * really pushes log tail further. It's responsibility of the caller to make
1088  * sure provided log tail information is valid (e.g. by holding
1089  * j_checkpoint_mutex all the time between computing log tail and calling this
1090  * function as is the case with jbd2_cleanup_journal_tail()).
1091  *
1092  * Requires j_checkpoint_mutex
1093  */
1094 int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
1095 {
1096         unsigned long freed;
1097         int ret;
1098
1099         BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1100
1101         /*
1102          * We cannot afford for write to remain in drive's caches since as
1103          * soon as we update j_tail, next transaction can start reusing journal
1104          * space and if we lose sb update during power failure we'd replay
1105          * old transaction with possibly newly overwritten data.
1106          */
1107         ret = jbd2_journal_update_sb_log_tail(journal, tid, block,
1108                                               REQ_SYNC | REQ_FUA);
1109         if (ret)
1110                 goto out;
1111
1112         write_lock(&journal->j_state_lock);
1113         freed = block - journal->j_tail;
1114         if (block < journal->j_tail)
1115                 freed += journal->j_last - journal->j_first;
1116
1117         trace_jbd2_update_log_tail(journal, tid, block, freed);
1118         jbd_debug(1,
1119                   "Cleaning journal tail from %u to %u (offset %lu), "
1120                   "freeing %lu\n",
1121                   journal->j_tail_sequence, tid, block, freed);
1122
1123         journal->j_free += freed;
1124         journal->j_tail_sequence = tid;
1125         journal->j_tail = block;
1126         write_unlock(&journal->j_state_lock);
1127
1128 out:
1129         return ret;
1130 }
1131
1132 /*
1133  * This is a variation of __jbd2_update_log_tail which checks for validity of
1134  * provided log tail and locks j_checkpoint_mutex. So it is safe against races
1135  * with other threads updating log tail.
1136  */
1137 void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
1138 {
1139         mutex_lock_io(&journal->j_checkpoint_mutex);
1140         if (tid_gt(tid, journal->j_tail_sequence))
1141                 __jbd2_update_log_tail(journal, tid, block);
1142         mutex_unlock(&journal->j_checkpoint_mutex);
1143 }
1144
1145 struct jbd2_stats_proc_session {
1146         journal_t *journal;
1147         struct transaction_stats_s *stats;
1148         int start;
1149         int max;
1150 };
1151
1152 static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos)
1153 {
1154         return *pos ? NULL : SEQ_START_TOKEN;
1155 }
1156
1157 static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos)
1158 {
1159         (*pos)++;
1160         return NULL;
1161 }
1162
1163 static int jbd2_seq_info_show(struct seq_file *seq, void *v)
1164 {
1165         struct jbd2_stats_proc_session *s = seq->private;
1166
1167         if (v != SEQ_START_TOKEN)
1168                 return 0;
1169         seq_printf(seq, "%lu transactions (%lu requested), "
1170                    "each up to %u blocks\n",
1171                    s->stats->ts_tid, s->stats->ts_requested,
1172                    s->journal->j_max_transaction_buffers);
1173         if (s->stats->ts_tid == 0)
1174                 return 0;
1175         seq_printf(seq, "average: \n  %ums waiting for transaction\n",
1176             jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid));
1177         seq_printf(seq, "  %ums request delay\n",
1178             (s->stats->ts_requested == 0) ? 0 :
1179             jiffies_to_msecs(s->stats->run.rs_request_delay /
1180                              s->stats->ts_requested));
1181         seq_printf(seq, "  %ums running transaction\n",
1182             jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid));
1183         seq_printf(seq, "  %ums transaction was being locked\n",
1184             jiffies_to_msecs(s->stats->run.rs_locked / s->stats->ts_tid));
1185         seq_printf(seq, "  %ums flushing data (in ordered mode)\n",
1186             jiffies_to_msecs(s->stats->run.rs_flushing / s->stats->ts_tid));
1187         seq_printf(seq, "  %ums logging transaction\n",
1188             jiffies_to_msecs(s->stats->run.rs_logging / s->stats->ts_tid));
1189         seq_printf(seq, "  %lluus average transaction commit time\n",
1190                    div_u64(s->journal->j_average_commit_time, 1000));
1191         seq_printf(seq, "  %lu handles per transaction\n",
1192             s->stats->run.rs_handle_count / s->stats->ts_tid);
1193         seq_printf(seq, "  %lu blocks per transaction\n",
1194             s->stats->run.rs_blocks / s->stats->ts_tid);
1195         seq_printf(seq, "  %lu logged blocks per transaction\n",
1196             s->stats->run.rs_blocks_logged / s->stats->ts_tid);
1197         return 0;
1198 }
1199
1200 static void jbd2_seq_info_stop(struct seq_file *seq, void *v)
1201 {
1202 }
1203
1204 static const struct seq_operations jbd2_seq_info_ops = {
1205         .start  = jbd2_seq_info_start,
1206         .next   = jbd2_seq_info_next,
1207         .stop   = jbd2_seq_info_stop,
1208         .show   = jbd2_seq_info_show,
1209 };
1210
1211 static int jbd2_seq_info_open(struct inode *inode, struct file *file)
1212 {
1213         journal_t *journal = PDE_DATA(inode);
1214         struct jbd2_stats_proc_session *s;
1215         int rc, size;
1216
1217         s = kmalloc(sizeof(*s), GFP_KERNEL);
1218         if (s == NULL)
1219                 return -ENOMEM;
1220         size = sizeof(struct transaction_stats_s);
1221         s->stats = kmalloc(size, GFP_KERNEL);
1222         if (s->stats == NULL) {
1223                 kfree(s);
1224                 return -ENOMEM;
1225         }
1226         spin_lock(&journal->j_history_lock);
1227         memcpy(s->stats, &journal->j_stats, size);
1228         s->journal = journal;
1229         spin_unlock(&journal->j_history_lock);
1230
1231         rc = seq_open(file, &jbd2_seq_info_ops);
1232         if (rc == 0) {
1233                 struct seq_file *m = file->private_data;
1234                 m->private = s;
1235         } else {
1236                 kfree(s->stats);
1237                 kfree(s);
1238         }
1239         return rc;
1240
1241 }
1242
1243 static int jbd2_seq_info_release(struct inode *inode, struct file *file)
1244 {
1245         struct seq_file *seq = file->private_data;
1246         struct jbd2_stats_proc_session *s = seq->private;
1247         kfree(s->stats);
1248         kfree(s);
1249         return seq_release(inode, file);
1250 }
1251
1252 static const struct proc_ops jbd2_info_proc_ops = {
1253         .proc_open      = jbd2_seq_info_open,
1254         .proc_read      = seq_read,
1255         .proc_lseek     = seq_lseek,
1256         .proc_release   = jbd2_seq_info_release,
1257 };
1258
1259 static struct proc_dir_entry *proc_jbd2_stats;
1260
1261 static void jbd2_stats_proc_init(journal_t *journal)
1262 {
1263         journal->j_proc_entry = proc_mkdir(journal->j_devname, proc_jbd2_stats);
1264         if (journal->j_proc_entry) {
1265                 proc_create_data("info", S_IRUGO, journal->j_proc_entry,
1266                                  &jbd2_info_proc_ops, journal);
1267         }
1268 }
1269
1270 static void jbd2_stats_proc_exit(journal_t *journal)
1271 {
1272         remove_proc_entry("info", journal->j_proc_entry);
1273         remove_proc_entry(journal->j_devname, proc_jbd2_stats);
1274 }
1275
1276 /* Minimum size of descriptor tag */
1277 static int jbd2_min_tag_size(void)
1278 {
1279         /*
1280          * Tag with 32-bit block numbers does not use last four bytes of the
1281          * structure
1282          */
1283         return sizeof(journal_block_tag_t) - 4;
1284 }
1285
1286 /*
1287  * Management for journal control blocks: functions to create and
1288  * destroy journal_t structures, and to initialise and read existing
1289  * journal blocks from disk.  */
1290
1291 /* First: create and setup a journal_t object in memory.  We initialise
1292  * very few fields yet: that has to wait until we have created the
1293  * journal structures from from scratch, or loaded them from disk. */
1294
1295 static journal_t *journal_init_common(struct block_device *bdev,
1296                         struct block_device *fs_dev,
1297                         unsigned long long start, int len, int blocksize)
1298 {
1299         static struct lock_class_key jbd2_trans_commit_key;
1300         journal_t *journal;
1301         int err;
1302         struct buffer_head *bh;
1303         int n;
1304
1305         journal = kzalloc(sizeof(*journal), GFP_KERNEL);
1306         if (!journal)
1307                 return NULL;
1308
1309         init_waitqueue_head(&journal->j_wait_transaction_locked);
1310         init_waitqueue_head(&journal->j_wait_done_commit);
1311         init_waitqueue_head(&journal->j_wait_commit);
1312         init_waitqueue_head(&journal->j_wait_updates);
1313         init_waitqueue_head(&journal->j_wait_reserved);
1314         init_waitqueue_head(&journal->j_fc_wait);
1315         mutex_init(&journal->j_abort_mutex);
1316         mutex_init(&journal->j_barrier);
1317         mutex_init(&journal->j_checkpoint_mutex);
1318         spin_lock_init(&journal->j_revoke_lock);
1319         spin_lock_init(&journal->j_list_lock);
1320         rwlock_init(&journal->j_state_lock);
1321
1322         journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE);
1323         journal->j_min_batch_time = 0;
1324         journal->j_max_batch_time = 15000; /* 15ms */
1325         atomic_set(&journal->j_reserved_credits, 0);
1326
1327         /* The journal is marked for error until we succeed with recovery! */
1328         journal->j_flags = JBD2_ABORT;
1329
1330         /* Set up a default-sized revoke table for the new mount. */
1331         err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
1332         if (err)
1333                 goto err_cleanup;
1334
1335         spin_lock_init(&journal->j_history_lock);
1336
1337         lockdep_init_map(&journal->j_trans_commit_map, "jbd2_handle",
1338                          &jbd2_trans_commit_key, 0);
1339
1340         /* journal descriptor can store up to n blocks -bzzz */
1341         journal->j_blocksize = blocksize;
1342         journal->j_dev = bdev;
1343         journal->j_fs_dev = fs_dev;
1344         journal->j_blk_offset = start;
1345         journal->j_total_len = len;
1346         /* We need enough buffers to write out full descriptor block. */
1347         n = journal->j_blocksize / jbd2_min_tag_size();
1348         journal->j_wbufsize = n;
1349         journal->j_fc_wbuf = NULL;
1350         journal->j_wbuf = kmalloc_array(n, sizeof(struct buffer_head *),
1351                                         GFP_KERNEL);
1352         if (!journal->j_wbuf)
1353                 goto err_cleanup;
1354
1355         bh = getblk_unmovable(journal->j_dev, start, journal->j_blocksize);
1356         if (!bh) {
1357                 pr_err("%s: Cannot get buffer for journal superblock\n",
1358                         __func__);
1359                 goto err_cleanup;
1360         }
1361         journal->j_sb_buffer = bh;
1362         journal->j_superblock = (journal_superblock_t *)bh->b_data;
1363
1364         return journal;
1365
1366 err_cleanup:
1367         kfree(journal->j_wbuf);
1368         jbd2_journal_destroy_revoke(journal);
1369         kfree(journal);
1370         return NULL;
1371 }
1372
1373 /* jbd2_journal_init_dev and jbd2_journal_init_inode:
1374  *
1375  * Create a journal structure assigned some fixed set of disk blocks to
1376  * the journal.  We don't actually touch those disk blocks yet, but we
1377  * need to set up all of the mapping information to tell the journaling
1378  * system where the journal blocks are.
1379  *
1380  */
1381
1382 /**
1383  *  journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
1384  *  @bdev: Block device on which to create the journal
1385  *  @fs_dev: Device which hold journalled filesystem for this journal.
1386  *  @start: Block nr Start of journal.
1387  *  @len:  Length of the journal in blocks.
1388  *  @blocksize: blocksize of journalling device
1389  *
1390  *  Returns: a newly created journal_t *
1391  *
1392  *  jbd2_journal_init_dev creates a journal which maps a fixed contiguous
1393  *  range of blocks on an arbitrary block device.
1394  *
1395  */
1396 journal_t *jbd2_journal_init_dev(struct block_device *bdev,
1397                         struct block_device *fs_dev,
1398                         unsigned long long start, int len, int blocksize)
1399 {
1400         journal_t *journal;
1401
1402         journal = journal_init_common(bdev, fs_dev, start, len, blocksize);
1403         if (!journal)
1404                 return NULL;
1405
1406         bdevname(journal->j_dev, journal->j_devname);
1407         strreplace(journal->j_devname, '/', '!');
1408         jbd2_stats_proc_init(journal);
1409
1410         return journal;
1411 }
1412
1413 /**
1414  *  journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
1415  *  @inode: An inode to create the journal in
1416  *
1417  * jbd2_journal_init_inode creates a journal which maps an on-disk inode as
1418  * the journal.  The inode must exist already, must support bmap() and
1419  * must have all data blocks preallocated.
1420  */
1421 journal_t *jbd2_journal_init_inode(struct inode *inode)
1422 {
1423         journal_t *journal;
1424         sector_t blocknr;
1425         char *p;
1426         int err = 0;
1427
1428         blocknr = 0;
1429         err = bmap(inode, &blocknr);
1430
1431         if (err || !blocknr) {
1432                 pr_err("%s: Cannot locate journal superblock\n",
1433                         __func__);
1434                 return NULL;
1435         }
1436
1437         jbd_debug(1, "JBD2: inode %s/%ld, size %lld, bits %d, blksize %ld\n",
1438                   inode->i_sb->s_id, inode->i_ino, (long long) inode->i_size,
1439                   inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
1440
1441         journal = journal_init_common(inode->i_sb->s_bdev, inode->i_sb->s_bdev,
1442                         blocknr, inode->i_size >> inode->i_sb->s_blocksize_bits,
1443                         inode->i_sb->s_blocksize);
1444         if (!journal)
1445                 return NULL;
1446
1447         journal->j_inode = inode;
1448         bdevname(journal->j_dev, journal->j_devname);
1449         p = strreplace(journal->j_devname, '/', '!');
1450         sprintf(p, "-%lu", journal->j_inode->i_ino);
1451         jbd2_stats_proc_init(journal);
1452
1453         return journal;
1454 }
1455
1456 /*
1457  * If the journal init or create aborts, we need to mark the journal
1458  * superblock as being NULL to prevent the journal destroy from writing
1459  * back a bogus superblock.
1460  */
1461 static void journal_fail_superblock(journal_t *journal)
1462 {
1463         struct buffer_head *bh = journal->j_sb_buffer;
1464         brelse(bh);
1465         journal->j_sb_buffer = NULL;
1466 }
1467
1468 /*
1469  * Given a journal_t structure, initialise the various fields for
1470  * startup of a new journaling session.  We use this both when creating
1471  * a journal, and after recovering an old journal to reset it for
1472  * subsequent use.
1473  */
1474
1475 static int journal_reset(journal_t *journal)
1476 {
1477         journal_superblock_t *sb = journal->j_superblock;
1478         unsigned long long first, last;
1479
1480         first = be32_to_cpu(sb->s_first);
1481         last = be32_to_cpu(sb->s_maxlen);
1482         if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) {
1483                 printk(KERN_ERR "JBD2: Journal too short (blocks %llu-%llu).\n",
1484                        first, last);
1485                 journal_fail_superblock(journal);
1486                 return -EINVAL;
1487         }
1488
1489         journal->j_first = first;
1490         journal->j_last = last;
1491
1492         journal->j_head = journal->j_first;
1493         journal->j_tail = journal->j_first;
1494         journal->j_free = journal->j_last - journal->j_first;
1495
1496         journal->j_tail_sequence = journal->j_transaction_sequence;
1497         journal->j_commit_sequence = journal->j_transaction_sequence - 1;
1498         journal->j_commit_request = journal->j_commit_sequence;
1499
1500         journal->j_max_transaction_buffers = jbd2_journal_get_max_txn_bufs(journal);
1501
1502         /*
1503          * Now that journal recovery is done, turn fast commits off here. This
1504          * way, if fast commit was enabled before the crash but if now FS has
1505          * disabled it, we don't enable fast commits.
1506          */
1507         jbd2_clear_feature_fast_commit(journal);
1508
1509         /*
1510          * As a special case, if the on-disk copy is already marked as needing
1511          * no recovery (s_start == 0), then we can safely defer the superblock
1512          * update until the next commit by setting JBD2_FLUSHED.  This avoids
1513          * attempting a write to a potential-readonly device.
1514          */
1515         if (sb->s_start == 0) {
1516                 jbd_debug(1, "JBD2: Skipping superblock update on recovered sb "
1517                         "(start %ld, seq %u, errno %d)\n",
1518                         journal->j_tail, journal->j_tail_sequence,
1519                         journal->j_errno);
1520                 journal->j_flags |= JBD2_FLUSHED;
1521         } else {
1522                 /* Lock here to make assertions happy... */
1523                 mutex_lock_io(&journal->j_checkpoint_mutex);
1524                 /*
1525                  * Update log tail information. We use REQ_FUA since new
1526                  * transaction will start reusing journal space and so we
1527                  * must make sure information about current log tail is on
1528                  * disk before that.
1529                  */
1530                 jbd2_journal_update_sb_log_tail(journal,
1531                                                 journal->j_tail_sequence,
1532                                                 journal->j_tail,
1533                                                 REQ_SYNC | REQ_FUA);
1534                 mutex_unlock(&journal->j_checkpoint_mutex);
1535         }
1536         return jbd2_journal_start_thread(journal);
1537 }
1538
1539 /*
1540  * This function expects that the caller will have locked the journal
1541  * buffer head, and will return with it unlocked
1542  */
1543 static int jbd2_write_superblock(journal_t *journal, int write_flags)
1544 {
1545         struct buffer_head *bh = journal->j_sb_buffer;
1546         journal_superblock_t *sb = journal->j_superblock;
1547         int ret;
1548
1549         /* Buffer got discarded which means block device got invalidated */
1550         if (!buffer_mapped(bh)) {
1551                 unlock_buffer(bh);
1552                 return -EIO;
1553         }
1554
1555         trace_jbd2_write_superblock(journal, write_flags);
1556         if (!(journal->j_flags & JBD2_BARRIER))
1557                 write_flags &= ~(REQ_FUA | REQ_PREFLUSH);
1558         if (buffer_write_io_error(bh)) {
1559                 /*
1560                  * Oh, dear.  A previous attempt to write the journal
1561                  * superblock failed.  This could happen because the
1562                  * USB device was yanked out.  Or it could happen to
1563                  * be a transient write error and maybe the block will
1564                  * be remapped.  Nothing we can do but to retry the
1565                  * write and hope for the best.
1566                  */
1567                 printk(KERN_ERR "JBD2: previous I/O error detected "
1568                        "for journal superblock update for %s.\n",
1569                        journal->j_devname);
1570                 clear_buffer_write_io_error(bh);
1571                 set_buffer_uptodate(bh);
1572         }
1573         if (jbd2_journal_has_csum_v2or3(journal))
1574                 sb->s_checksum = jbd2_superblock_csum(journal, sb);
1575         get_bh(bh);
1576         bh->b_end_io = end_buffer_write_sync;
1577         ret = submit_bh(REQ_OP_WRITE, write_flags, bh);
1578         wait_on_buffer(bh);
1579         if (buffer_write_io_error(bh)) {
1580                 clear_buffer_write_io_error(bh);
1581                 set_buffer_uptodate(bh);
1582                 ret = -EIO;
1583         }
1584         if (ret) {
1585                 printk(KERN_ERR "JBD2: Error %d detected when updating "
1586                        "journal superblock for %s.\n", ret,
1587                        journal->j_devname);
1588                 if (!is_journal_aborted(journal))
1589                         jbd2_journal_abort(journal, ret);
1590         }
1591
1592         return ret;
1593 }
1594
1595 /**
1596  * jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk.
1597  * @journal: The journal to update.
1598  * @tail_tid: TID of the new transaction at the tail of the log
1599  * @tail_block: The first block of the transaction at the tail of the log
1600  * @write_op: With which operation should we write the journal sb
1601  *
1602  * Update a journal's superblock information about log tail and write it to
1603  * disk, waiting for the IO to complete.
1604  */
1605 int jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
1606                                      unsigned long tail_block, int write_op)
1607 {
1608         journal_superblock_t *sb = journal->j_superblock;
1609         int ret;
1610
1611         if (is_journal_aborted(journal))
1612                 return -EIO;
1613         if (test_bit(JBD2_CHECKPOINT_IO_ERROR, &journal->j_atomic_flags)) {
1614                 jbd2_journal_abort(journal, -EIO);
1615                 return -EIO;
1616         }
1617
1618         BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1619         jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
1620                   tail_block, tail_tid);
1621
1622         lock_buffer(journal->j_sb_buffer);
1623         sb->s_sequence = cpu_to_be32(tail_tid);
1624         sb->s_start    = cpu_to_be32(tail_block);
1625
1626         ret = jbd2_write_superblock(journal, write_op);
1627         if (ret)
1628                 goto out;
1629
1630         /* Log is no longer empty */
1631         write_lock(&journal->j_state_lock);
1632         WARN_ON(!sb->s_sequence);
1633         journal->j_flags &= ~JBD2_FLUSHED;
1634         write_unlock(&journal->j_state_lock);
1635
1636 out:
1637         return ret;
1638 }
1639
1640 /**
1641  * jbd2_mark_journal_empty() - Mark on disk journal as empty.
1642  * @journal: The journal to update.
1643  * @write_op: With which operation should we write the journal sb
1644  *
1645  * Update a journal's dynamic superblock fields to show that journal is empty.
1646  * Write updated superblock to disk waiting for IO to complete.
1647  */
1648 static void jbd2_mark_journal_empty(journal_t *journal, int write_op)
1649 {
1650         journal_superblock_t *sb = journal->j_superblock;
1651         bool had_fast_commit = false;
1652
1653         BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1654         lock_buffer(journal->j_sb_buffer);
1655         if (sb->s_start == 0) {         /* Is it already empty? */
1656                 unlock_buffer(journal->j_sb_buffer);
1657                 return;
1658         }
1659
1660         jbd_debug(1, "JBD2: Marking journal as empty (seq %u)\n",
1661                   journal->j_tail_sequence);
1662
1663         sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
1664         sb->s_start    = cpu_to_be32(0);
1665         if (jbd2_has_feature_fast_commit(journal)) {
1666                 /*
1667                  * When journal is clean, no need to commit fast commit flag and
1668                  * make file system incompatible with older kernels.
1669                  */
1670                 jbd2_clear_feature_fast_commit(journal);
1671                 had_fast_commit = true;
1672         }
1673
1674         jbd2_write_superblock(journal, write_op);
1675
1676         if (had_fast_commit)
1677                 jbd2_set_feature_fast_commit(journal);
1678
1679         /* Log is no longer empty */
1680         write_lock(&journal->j_state_lock);
1681         journal->j_flags |= JBD2_FLUSHED;
1682         write_unlock(&journal->j_state_lock);
1683 }
1684
1685 /**
1686  * __jbd2_journal_erase() - Discard or zeroout journal blocks (excluding superblock)
1687  * @journal: The journal to erase.
1688  * @flags: A discard/zeroout request is sent for each physically contigous
1689  *      region of the journal. Either JBD2_JOURNAL_FLUSH_DISCARD or
1690  *      JBD2_JOURNAL_FLUSH_ZEROOUT must be set to determine which operation
1691  *      to perform.
1692  *
1693  * Note: JBD2_JOURNAL_FLUSH_ZEROOUT attempts to use hardware offload. Zeroes
1694  * will be explicitly written if no hardware offload is available, see
1695  * blkdev_issue_zeroout for more details.
1696  */
1697 static int __jbd2_journal_erase(journal_t *journal, unsigned int flags)
1698 {
1699         int err = 0;
1700         unsigned long block, log_offset; /* logical */
1701         unsigned long long phys_block, block_start, block_stop; /* physical */
1702         loff_t byte_start, byte_stop, byte_count;
1703         struct request_queue *q = bdev_get_queue(journal->j_dev);
1704
1705         /* flags must be set to either discard or zeroout */
1706         if ((flags & ~JBD2_JOURNAL_FLUSH_VALID) || !flags ||
1707                         ((flags & JBD2_JOURNAL_FLUSH_DISCARD) &&
1708                         (flags & JBD2_JOURNAL_FLUSH_ZEROOUT)))
1709                 return -EINVAL;
1710
1711         if (!q)
1712                 return -ENXIO;
1713
1714         if ((flags & JBD2_JOURNAL_FLUSH_DISCARD) && !blk_queue_discard(q))
1715                 return -EOPNOTSUPP;
1716
1717         /*
1718          * lookup block mapping and issue discard/zeroout for each
1719          * contiguous region
1720          */
1721         log_offset = be32_to_cpu(journal->j_superblock->s_first);
1722         block_start =  ~0ULL;
1723         for (block = log_offset; block < journal->j_total_len; block++) {
1724                 err = jbd2_journal_bmap(journal, block, &phys_block);
1725                 if (err) {
1726                         pr_err("JBD2: bad block at offset %lu", block);
1727                         return err;
1728                 }
1729
1730                 if (block_start == ~0ULL) {
1731                         block_start = phys_block;
1732                         block_stop = block_start - 1;
1733                 }
1734
1735                 /*
1736                  * last block not contiguous with current block,
1737                  * process last contiguous region and return to this block on
1738                  * next loop
1739                  */
1740                 if (phys_block != block_stop + 1) {
1741                         block--;
1742                 } else {
1743                         block_stop++;
1744                         /*
1745                          * if this isn't the last block of journal,
1746                          * no need to process now because next block may also
1747                          * be part of this contiguous region
1748                          */
1749                         if (block != journal->j_total_len - 1)
1750                                 continue;
1751                 }
1752
1753                 /*
1754                  * end of contiguous region or this is last block of journal,
1755                  * take care of the region
1756                  */
1757                 byte_start = block_start * journal->j_blocksize;
1758                 byte_stop = block_stop * journal->j_blocksize;
1759                 byte_count = (block_stop - block_start + 1) *
1760                                 journal->j_blocksize;
1761
1762                 truncate_inode_pages_range(journal->j_dev->bd_inode->i_mapping,
1763                                 byte_start, byte_stop);
1764
1765                 if (flags & JBD2_JOURNAL_FLUSH_DISCARD) {
1766                         err = blkdev_issue_discard(journal->j_dev,
1767                                         byte_start >> SECTOR_SHIFT,
1768                                         byte_count >> SECTOR_SHIFT,
1769                                         GFP_NOFS, 0);
1770                 } else if (flags & JBD2_JOURNAL_FLUSH_ZEROOUT) {
1771                         err = blkdev_issue_zeroout(journal->j_dev,
1772                                         byte_start >> SECTOR_SHIFT,
1773                                         byte_count >> SECTOR_SHIFT,
1774                                         GFP_NOFS, 0);
1775                 }
1776
1777                 if (unlikely(err != 0)) {
1778                         pr_err("JBD2: (error %d) unable to wipe journal at physical blocks %llu - %llu",
1779                                         err, block_start, block_stop);
1780                         return err;
1781                 }
1782
1783                 /* reset start and stop after processing a region */
1784                 block_start = ~0ULL;
1785         }
1786
1787         return blkdev_issue_flush(journal->j_dev);
1788 }
1789
1790 /**
1791  * jbd2_journal_update_sb_errno() - Update error in the journal.
1792  * @journal: The journal to update.
1793  *
1794  * Update a journal's errno.  Write updated superblock to disk waiting for IO
1795  * to complete.
1796  */
1797 void jbd2_journal_update_sb_errno(journal_t *journal)
1798 {
1799         journal_superblock_t *sb = journal->j_superblock;
1800         int errcode;
1801
1802         lock_buffer(journal->j_sb_buffer);
1803         errcode = journal->j_errno;
1804         if (errcode == -ESHUTDOWN)
1805                 errcode = 0;
1806         jbd_debug(1, "JBD2: updating superblock error (errno %d)\n", errcode);
1807         sb->s_errno    = cpu_to_be32(errcode);
1808
1809         jbd2_write_superblock(journal, REQ_SYNC | REQ_FUA);
1810 }
1811 EXPORT_SYMBOL(jbd2_journal_update_sb_errno);
1812
1813 static int journal_revoke_records_per_block(journal_t *journal)
1814 {
1815         int record_size;
1816         int space = journal->j_blocksize - sizeof(jbd2_journal_revoke_header_t);
1817
1818         if (jbd2_has_feature_64bit(journal))
1819                 record_size = 8;
1820         else
1821                 record_size = 4;
1822
1823         if (jbd2_journal_has_csum_v2or3(journal))
1824                 space -= sizeof(struct jbd2_journal_block_tail);
1825         return space / record_size;
1826 }
1827
1828 /*
1829  * Read the superblock for a given journal, performing initial
1830  * validation of the format.
1831  */
1832 static int journal_get_superblock(journal_t *journal)
1833 {
1834         struct buffer_head *bh;
1835         journal_superblock_t *sb;
1836         int err = -EIO;
1837
1838         bh = journal->j_sb_buffer;
1839
1840         J_ASSERT(bh != NULL);
1841         if (!buffer_uptodate(bh)) {
1842                 ll_rw_block(REQ_OP_READ, 0, 1, &bh);
1843                 wait_on_buffer(bh);
1844                 if (!buffer_uptodate(bh)) {
1845                         printk(KERN_ERR
1846                                 "JBD2: IO error reading journal superblock\n");
1847                         goto out;
1848                 }
1849         }
1850
1851         if (buffer_verified(bh))
1852                 return 0;
1853
1854         sb = journal->j_superblock;
1855
1856         err = -EINVAL;
1857
1858         if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
1859             sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1860                 printk(KERN_WARNING "JBD2: no valid journal superblock found\n");
1861                 goto out;
1862         }
1863
1864         switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1865         case JBD2_SUPERBLOCK_V1:
1866                 journal->j_format_version = 1;
1867                 break;
1868         case JBD2_SUPERBLOCK_V2:
1869                 journal->j_format_version = 2;
1870                 break;
1871         default:
1872                 printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n");
1873                 goto out;
1874         }
1875
1876         if (be32_to_cpu(sb->s_maxlen) < journal->j_total_len)
1877                 journal->j_total_len = be32_to_cpu(sb->s_maxlen);
1878         else if (be32_to_cpu(sb->s_maxlen) > journal->j_total_len) {
1879                 printk(KERN_WARNING "JBD2: journal file too short\n");
1880                 goto out;
1881         }
1882
1883         if (be32_to_cpu(sb->s_first) == 0 ||
1884             be32_to_cpu(sb->s_first) >= journal->j_total_len) {
1885                 printk(KERN_WARNING
1886                         "JBD2: Invalid start block of journal: %u\n",
1887                         be32_to_cpu(sb->s_first));
1888                 goto out;
1889         }
1890
1891         if (jbd2_has_feature_csum2(journal) &&
1892             jbd2_has_feature_csum3(journal)) {
1893                 /* Can't have checksum v2 and v3 at the same time! */
1894                 printk(KERN_ERR "JBD2: Can't enable checksumming v2 and v3 "
1895                        "at the same time!\n");
1896                 goto out;
1897         }
1898
1899         if (jbd2_journal_has_csum_v2or3_feature(journal) &&
1900             jbd2_has_feature_checksum(journal)) {
1901                 /* Can't have checksum v1 and v2 on at the same time! */
1902                 printk(KERN_ERR "JBD2: Can't enable checksumming v1 and v2/3 "
1903                        "at the same time!\n");
1904                 goto out;
1905         }
1906
1907         if (!jbd2_verify_csum_type(journal, sb)) {
1908                 printk(KERN_ERR "JBD2: Unknown checksum type\n");
1909                 goto out;
1910         }
1911
1912         /* Load the checksum driver */
1913         if (jbd2_journal_has_csum_v2or3_feature(journal)) {
1914                 journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
1915                 if (IS_ERR(journal->j_chksum_driver)) {
1916                         printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
1917                         err = PTR_ERR(journal->j_chksum_driver);
1918                         journal->j_chksum_driver = NULL;
1919                         goto out;
1920                 }
1921         }
1922
1923         if (jbd2_journal_has_csum_v2or3(journal)) {
1924                 /* Check superblock checksum */
1925                 if (sb->s_checksum != jbd2_superblock_csum(journal, sb)) {
1926                         printk(KERN_ERR "JBD2: journal checksum error\n");
1927                         err = -EFSBADCRC;
1928                         goto out;
1929                 }
1930
1931                 /* Precompute checksum seed for all metadata */
1932                 journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
1933                                                    sizeof(sb->s_uuid));
1934         }
1935
1936         journal->j_revoke_records_per_block =
1937                                 journal_revoke_records_per_block(journal);
1938         set_buffer_verified(bh);
1939
1940         return 0;
1941
1942 out:
1943         journal_fail_superblock(journal);
1944         return err;
1945 }
1946
1947 /*
1948  * Load the on-disk journal superblock and read the key fields into the
1949  * journal_t.
1950  */
1951
1952 static int load_superblock(journal_t *journal)
1953 {
1954         int err;
1955         journal_superblock_t *sb;
1956         int num_fc_blocks;
1957
1958         err = journal_get_superblock(journal);
1959         if (err)
1960                 return err;
1961
1962         sb = journal->j_superblock;
1963
1964         journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
1965         journal->j_tail = be32_to_cpu(sb->s_start);
1966         journal->j_first = be32_to_cpu(sb->s_first);
1967         journal->j_errno = be32_to_cpu(sb->s_errno);
1968         journal->j_last = be32_to_cpu(sb->s_maxlen);
1969
1970         if (jbd2_has_feature_fast_commit(journal)) {
1971                 journal->j_fc_last = be32_to_cpu(sb->s_maxlen);
1972                 num_fc_blocks = jbd2_journal_get_num_fc_blks(sb);
1973                 if (journal->j_last - num_fc_blocks >= JBD2_MIN_JOURNAL_BLOCKS)
1974                         journal->j_last = journal->j_fc_last - num_fc_blocks;
1975                 journal->j_fc_first = journal->j_last + 1;
1976                 journal->j_fc_off = 0;
1977         }
1978
1979         return 0;
1980 }
1981
1982
1983 /**
1984  * jbd2_journal_load() - Read journal from disk.
1985  * @journal: Journal to act on.
1986  *
1987  * Given a journal_t structure which tells us which disk blocks contain
1988  * a journal, read the journal from disk to initialise the in-memory
1989  * structures.
1990  */
1991 int jbd2_journal_load(journal_t *journal)
1992 {
1993         int err;
1994         journal_superblock_t *sb;
1995
1996         err = load_superblock(journal);
1997         if (err)
1998                 return err;
1999
2000         sb = journal->j_superblock;
2001         /* If this is a V2 superblock, then we have to check the
2002          * features flags on it. */
2003
2004         if (journal->j_format_version >= 2) {
2005                 if ((sb->s_feature_ro_compat &
2006                      ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) ||
2007                     (sb->s_feature_incompat &
2008                      ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) {
2009                         printk(KERN_WARNING
2010                                 "JBD2: Unrecognised features on journal\n");
2011                         return -EINVAL;
2012                 }
2013         }
2014
2015         /*
2016          * Create a slab for this blocksize
2017          */
2018         err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize));
2019         if (err)
2020                 return err;
2021
2022         /* Let the recovery code check whether it needs to recover any
2023          * data from the journal. */
2024         if (jbd2_journal_recover(journal))
2025                 goto recovery_error;
2026
2027         if (journal->j_failed_commit) {
2028                 printk(KERN_ERR "JBD2: journal transaction %u on %s "
2029                        "is corrupt.\n", journal->j_failed_commit,
2030                        journal->j_devname);
2031                 return -EFSCORRUPTED;
2032         }
2033         /*
2034          * clear JBD2_ABORT flag initialized in journal_init_common
2035          * here to update log tail information with the newest seq.
2036          */
2037         journal->j_flags &= ~JBD2_ABORT;
2038
2039         /* OK, we've finished with the dynamic journal bits:
2040          * reinitialise the dynamic contents of the superblock in memory
2041          * and reset them on disk. */
2042         if (journal_reset(journal))
2043                 goto recovery_error;
2044
2045         journal->j_flags |= JBD2_LOADED;
2046         return 0;
2047
2048 recovery_error:
2049         printk(KERN_WARNING "JBD2: recovery failed\n");
2050         return -EIO;
2051 }
2052
2053 /**
2054  * jbd2_journal_shrink_scan()
2055  *
2056  * Scan the checkpointed buffer on the checkpoint list and release the
2057  * journal_head.
2058  */
2059 static unsigned long jbd2_journal_shrink_scan(struct shrinker *shrink,
2060                                               struct shrink_control *sc)
2061 {
2062         journal_t *journal = container_of(shrink, journal_t, j_shrinker);
2063         unsigned long nr_to_scan = sc->nr_to_scan;
2064         unsigned long nr_shrunk;
2065         unsigned long count;
2066
2067         count = percpu_counter_read_positive(&journal->j_jh_shrink_count);
2068         trace_jbd2_shrink_scan_enter(journal, sc->nr_to_scan, count);
2069
2070         nr_shrunk = jbd2_journal_shrink_checkpoint_list(journal, &nr_to_scan);
2071
2072         count = percpu_counter_read_positive(&journal->j_jh_shrink_count);
2073         trace_jbd2_shrink_scan_exit(journal, nr_to_scan, nr_shrunk, count);
2074
2075         return nr_shrunk;
2076 }
2077
2078 /**
2079  * jbd2_journal_shrink_count()
2080  *
2081  * Count the number of checkpoint buffers on the checkpoint list.
2082  */
2083 static unsigned long jbd2_journal_shrink_count(struct shrinker *shrink,
2084                                                struct shrink_control *sc)
2085 {
2086         journal_t *journal = container_of(shrink, journal_t, j_shrinker);
2087         unsigned long count;
2088
2089         count = percpu_counter_read_positive(&journal->j_jh_shrink_count);
2090         trace_jbd2_shrink_count(journal, sc->nr_to_scan, count);
2091
2092         return count;
2093 }
2094
2095 /**
2096  * jbd2_journal_register_shrinker()
2097  * @journal: Journal to act on.
2098  *
2099  * Init a percpu counter to record the checkpointed buffers on the checkpoint
2100  * list and register a shrinker to release their journal_head.
2101  */
2102 int jbd2_journal_register_shrinker(journal_t *journal)
2103 {
2104         int err;
2105
2106         journal->j_shrink_transaction = NULL;
2107
2108         err = percpu_counter_init(&journal->j_jh_shrink_count, 0, GFP_KERNEL);
2109         if (err)
2110                 return err;
2111
2112         journal->j_shrinker.scan_objects = jbd2_journal_shrink_scan;
2113         journal->j_shrinker.count_objects = jbd2_journal_shrink_count;
2114         journal->j_shrinker.seeks = DEFAULT_SEEKS;
2115         journal->j_shrinker.batch = journal->j_max_transaction_buffers;
2116
2117         err = register_shrinker(&journal->j_shrinker);
2118         if (err) {
2119                 percpu_counter_destroy(&journal->j_jh_shrink_count);
2120                 return err;
2121         }
2122
2123         return 0;
2124 }
2125 EXPORT_SYMBOL(jbd2_journal_register_shrinker);
2126
2127 /**
2128  * jbd2_journal_unregister_shrinker()
2129  * @journal: Journal to act on.
2130  *
2131  * Unregister the checkpointed buffer shrinker and destroy the percpu counter.
2132  */
2133 void jbd2_journal_unregister_shrinker(journal_t *journal)
2134 {
2135         percpu_counter_destroy(&journal->j_jh_shrink_count);
2136         unregister_shrinker(&journal->j_shrinker);
2137 }
2138 EXPORT_SYMBOL(jbd2_journal_unregister_shrinker);
2139
2140 /**
2141  * jbd2_journal_destroy() - Release a journal_t structure.
2142  * @journal: Journal to act on.
2143  *
2144  * Release a journal_t structure once it is no longer in use by the
2145  * journaled object.
2146  * Return <0 if we couldn't clean up the journal.
2147  */
2148 int jbd2_journal_destroy(journal_t *journal)
2149 {
2150         int err = 0;
2151
2152         /* Wait for the commit thread to wake up and die. */
2153         journal_kill_thread(journal);
2154
2155         /* Force a final log commit */
2156         if (journal->j_running_transaction)
2157                 jbd2_journal_commit_transaction(journal);
2158
2159         /* Force any old transactions to disk */
2160
2161         /* Totally anal locking here... */
2162         spin_lock(&journal->j_list_lock);
2163         while (journal->j_checkpoint_transactions != NULL) {
2164                 spin_unlock(&journal->j_list_lock);
2165                 mutex_lock_io(&journal->j_checkpoint_mutex);
2166                 err = jbd2_log_do_checkpoint(journal);
2167                 mutex_unlock(&journal->j_checkpoint_mutex);
2168                 /*
2169                  * If checkpointing failed, just free the buffers to avoid
2170                  * looping forever
2171                  */
2172                 if (err) {
2173                         jbd2_journal_destroy_checkpoint(journal);
2174                         spin_lock(&journal->j_list_lock);
2175                         break;
2176                 }
2177                 spin_lock(&journal->j_list_lock);
2178         }
2179
2180         J_ASSERT(journal->j_running_transaction == NULL);
2181         J_ASSERT(journal->j_committing_transaction == NULL);
2182         J_ASSERT(journal->j_checkpoint_transactions == NULL);
2183         spin_unlock(&journal->j_list_lock);
2184
2185         /*
2186          * OK, all checkpoint transactions have been checked, now check the
2187          * write out io error flag and abort the journal if some buffer failed
2188          * to write back to the original location, otherwise the filesystem
2189          * may become inconsistent.
2190          */
2191         if (!is_journal_aborted(journal) &&
2192             test_bit(JBD2_CHECKPOINT_IO_ERROR, &journal->j_atomic_flags))
2193                 jbd2_journal_abort(journal, -EIO);
2194
2195         if (journal->j_sb_buffer) {
2196                 if (!is_journal_aborted(journal)) {
2197                         mutex_lock_io(&journal->j_checkpoint_mutex);
2198
2199                         write_lock(&journal->j_state_lock);
2200                         journal->j_tail_sequence =
2201                                 ++journal->j_transaction_sequence;
2202                         write_unlock(&journal->j_state_lock);
2203
2204                         jbd2_mark_journal_empty(journal,
2205                                         REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
2206                         mutex_unlock(&journal->j_checkpoint_mutex);
2207                 } else
2208                         err = -EIO;
2209                 brelse(journal->j_sb_buffer);
2210         }
2211
2212         jbd2_journal_unregister_shrinker(journal);
2213
2214         if (journal->j_proc_entry)
2215                 jbd2_stats_proc_exit(journal);
2216         iput(journal->j_inode);
2217         if (journal->j_revoke)
2218                 jbd2_journal_destroy_revoke(journal);
2219         if (journal->j_chksum_driver)
2220                 crypto_free_shash(journal->j_chksum_driver);
2221         kfree(journal->j_fc_wbuf);
2222         kfree(journal->j_wbuf);
2223         kfree(journal);
2224
2225         return err;
2226 }
2227
2228
2229 /**
2230  * jbd2_journal_check_used_features() - Check if features specified are used.
2231  * @journal: Journal to check.
2232  * @compat: bitmask of compatible features
2233  * @ro: bitmask of features that force read-only mount
2234  * @incompat: bitmask of incompatible features
2235  *
2236  * Check whether the journal uses all of a given set of
2237  * features.  Return true (non-zero) if it does.
2238  **/
2239
2240 int jbd2_journal_check_used_features(journal_t *journal, unsigned long compat,
2241                                  unsigned long ro, unsigned long incompat)
2242 {
2243         journal_superblock_t *sb;
2244
2245         if (!compat && !ro && !incompat)
2246                 return 1;
2247         /* Load journal superblock if it is not loaded yet. */
2248         if (journal->j_format_version == 0 &&
2249             journal_get_superblock(journal) != 0)
2250                 return 0;
2251         if (journal->j_format_version == 1)
2252                 return 0;
2253
2254         sb = journal->j_superblock;
2255
2256         if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
2257             ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
2258             ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
2259                 return 1;
2260
2261         return 0;
2262 }
2263
2264 /**
2265  * jbd2_journal_check_available_features() - Check feature set in journalling layer
2266  * @journal: Journal to check.
2267  * @compat: bitmask of compatible features
2268  * @ro: bitmask of features that force read-only mount
2269  * @incompat: bitmask of incompatible features
2270  *
2271  * Check whether the journaling code supports the use of
2272  * all of a given set of features on this journal.  Return true
2273  * (non-zero) if it can. */
2274
2275 int jbd2_journal_check_available_features(journal_t *journal, unsigned long compat,
2276                                       unsigned long ro, unsigned long incompat)
2277 {
2278         if (!compat && !ro && !incompat)
2279                 return 1;
2280
2281         /* We can support any known requested features iff the
2282          * superblock is in version 2.  Otherwise we fail to support any
2283          * extended sb features. */
2284
2285         if (journal->j_format_version != 2)
2286                 return 0;
2287
2288         if ((compat   & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
2289             (ro       & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro &&
2290             (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat)
2291                 return 1;
2292
2293         return 0;
2294 }
2295
2296 static int
2297 jbd2_journal_initialize_fast_commit(journal_t *journal)
2298 {
2299         journal_superblock_t *sb = journal->j_superblock;
2300         unsigned long long num_fc_blks;
2301
2302         num_fc_blks = jbd2_journal_get_num_fc_blks(sb);
2303         if (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS)
2304                 return -ENOSPC;
2305
2306         /* Are we called twice? */
2307         WARN_ON(journal->j_fc_wbuf != NULL);
2308         journal->j_fc_wbuf = kmalloc_array(num_fc_blks,
2309                                 sizeof(struct buffer_head *), GFP_KERNEL);
2310         if (!journal->j_fc_wbuf)
2311                 return -ENOMEM;
2312
2313         journal->j_fc_wbufsize = num_fc_blks;
2314         journal->j_fc_last = journal->j_last;
2315         journal->j_last = journal->j_fc_last - num_fc_blks;
2316         journal->j_fc_first = journal->j_last + 1;
2317         journal->j_fc_off = 0;
2318         journal->j_free = journal->j_last - journal->j_first;
2319         journal->j_max_transaction_buffers =
2320                 jbd2_journal_get_max_txn_bufs(journal);
2321
2322         return 0;
2323 }
2324
2325 /**
2326  * jbd2_journal_set_features() - Mark a given journal feature in the superblock
2327  * @journal: Journal to act on.
2328  * @compat: bitmask of compatible features
2329  * @ro: bitmask of features that force read-only mount
2330  * @incompat: bitmask of incompatible features
2331  *
2332  * Mark a given journal feature as present on the
2333  * superblock.  Returns true if the requested features could be set.
2334  *
2335  */
2336
2337 int jbd2_journal_set_features(journal_t *journal, unsigned long compat,
2338                           unsigned long ro, unsigned long incompat)
2339 {
2340 #define INCOMPAT_FEATURE_ON(f) \
2341                 ((incompat & (f)) && !(sb->s_feature_incompat & cpu_to_be32(f)))
2342 #define COMPAT_FEATURE_ON(f) \
2343                 ((compat & (f)) && !(sb->s_feature_compat & cpu_to_be32(f)))
2344         journal_superblock_t *sb;
2345
2346         if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
2347                 return 1;
2348
2349         if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
2350                 return 0;
2351
2352         /* If enabling v2 checksums, turn on v3 instead */
2353         if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V2) {
2354                 incompat &= ~JBD2_FEATURE_INCOMPAT_CSUM_V2;
2355                 incompat |= JBD2_FEATURE_INCOMPAT_CSUM_V3;
2356         }
2357
2358         /* Asking for checksumming v3 and v1?  Only give them v3. */
2359         if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V3 &&
2360             compat & JBD2_FEATURE_COMPAT_CHECKSUM)
2361                 compat &= ~JBD2_FEATURE_COMPAT_CHECKSUM;
2362
2363         jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
2364                   compat, ro, incompat);
2365
2366         sb = journal->j_superblock;
2367
2368         if (incompat & JBD2_FEATURE_INCOMPAT_FAST_COMMIT) {
2369                 if (jbd2_journal_initialize_fast_commit(journal)) {
2370                         pr_err("JBD2: Cannot enable fast commits.\n");
2371                         return 0;
2372                 }
2373         }
2374
2375         /* Load the checksum driver if necessary */
2376         if ((journal->j_chksum_driver == NULL) &&
2377             INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
2378                 journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
2379                 if (IS_ERR(journal->j_chksum_driver)) {
2380                         printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
2381                         journal->j_chksum_driver = NULL;
2382                         return 0;
2383                 }
2384                 /* Precompute checksum seed for all metadata */
2385                 journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
2386                                                    sizeof(sb->s_uuid));
2387         }
2388
2389         lock_buffer(journal->j_sb_buffer);
2390
2391         /* If enabling v3 checksums, update superblock */
2392         if (INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
2393                 sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
2394                 sb->s_feature_compat &=
2395                         ~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
2396         }
2397
2398         /* If enabling v1 checksums, downgrade superblock */
2399         if (COMPAT_FEATURE_ON(JBD2_FEATURE_COMPAT_CHECKSUM))
2400                 sb->s_feature_incompat &=
2401                         ~cpu_to_be32(JBD2_FEATURE_INCOMPAT_CSUM_V2 |
2402                                      JBD2_FEATURE_INCOMPAT_CSUM_V3);
2403
2404         sb->s_feature_compat    |= cpu_to_be32(compat);
2405         sb->s_feature_ro_compat |= cpu_to_be32(ro);
2406         sb->s_feature_incompat  |= cpu_to_be32(incompat);
2407         unlock_buffer(journal->j_sb_buffer);
2408         journal->j_revoke_records_per_block =
2409                                 journal_revoke_records_per_block(journal);
2410
2411         return 1;
2412 #undef COMPAT_FEATURE_ON
2413 #undef INCOMPAT_FEATURE_ON
2414 }
2415
2416 /*
2417  * jbd2_journal_clear_features() - Clear a given journal feature in the
2418  *                                  superblock
2419  * @journal: Journal to act on.
2420  * @compat: bitmask of compatible features
2421  * @ro: bitmask of features that force read-only mount
2422  * @incompat: bitmask of incompatible features
2423  *
2424  * Clear a given journal feature as present on the
2425  * superblock.
2426  */
2427 void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
2428                                 unsigned long ro, unsigned long incompat)
2429 {
2430         journal_superblock_t *sb;
2431
2432         jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
2433                   compat, ro, incompat);
2434
2435         sb = journal->j_superblock;
2436
2437         sb->s_feature_compat    &= ~cpu_to_be32(compat);
2438         sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
2439         sb->s_feature_incompat  &= ~cpu_to_be32(incompat);
2440         journal->j_revoke_records_per_block =
2441                                 journal_revoke_records_per_block(journal);
2442 }
2443 EXPORT_SYMBOL(jbd2_journal_clear_features);
2444
2445 /**
2446  * jbd2_journal_flush() - Flush journal
2447  * @journal: Journal to act on.
2448  * @flags: optional operation on the journal blocks after the flush (see below)
2449  *
2450  * Flush all data for a given journal to disk and empty the journal.
2451  * Filesystems can use this when remounting readonly to ensure that
2452  * recovery does not need to happen on remount. Optionally, a discard or zeroout
2453  * can be issued on the journal blocks after flushing.
2454  *
2455  * flags:
2456  *      JBD2_JOURNAL_FLUSH_DISCARD: issues discards for the journal blocks
2457  *      JBD2_JOURNAL_FLUSH_ZEROOUT: issues zeroouts for the journal blocks
2458  */
2459 int jbd2_journal_flush(journal_t *journal, unsigned int flags)
2460 {
2461         int err = 0;
2462         transaction_t *transaction = NULL;
2463
2464         write_lock(&journal->j_state_lock);
2465
2466         /* Force everything buffered to the log... */
2467         if (journal->j_running_transaction) {
2468                 transaction = journal->j_running_transaction;
2469                 __jbd2_log_start_commit(journal, transaction->t_tid);
2470         } else if (journal->j_committing_transaction)
2471                 transaction = journal->j_committing_transaction;
2472
2473         /* Wait for the log commit to complete... */
2474         if (transaction) {
2475                 tid_t tid = transaction->t_tid;
2476
2477                 write_unlock(&journal->j_state_lock);
2478                 jbd2_log_wait_commit(journal, tid);
2479         } else {
2480                 write_unlock(&journal->j_state_lock);
2481         }
2482
2483         /* ...and flush everything in the log out to disk. */
2484         spin_lock(&journal->j_list_lock);
2485         while (!err && journal->j_checkpoint_transactions != NULL) {
2486                 spin_unlock(&journal->j_list_lock);
2487                 mutex_lock_io(&journal->j_checkpoint_mutex);
2488                 err = jbd2_log_do_checkpoint(journal);
2489                 mutex_unlock(&journal->j_checkpoint_mutex);
2490                 spin_lock(&journal->j_list_lock);
2491         }
2492         spin_unlock(&journal->j_list_lock);
2493
2494         if (is_journal_aborted(journal))
2495                 return -EIO;
2496
2497         mutex_lock_io(&journal->j_checkpoint_mutex);
2498         if (!err) {
2499                 err = jbd2_cleanup_journal_tail(journal);
2500                 if (err < 0) {
2501                         mutex_unlock(&journal->j_checkpoint_mutex);
2502                         goto out;
2503                 }
2504                 err = 0;
2505         }
2506
2507         /* Finally, mark the journal as really needing no recovery.
2508          * This sets s_start==0 in the underlying superblock, which is
2509          * the magic code for a fully-recovered superblock.  Any future
2510          * commits of data to the journal will restore the current
2511          * s_start value. */
2512         jbd2_mark_journal_empty(journal, REQ_SYNC | REQ_FUA);
2513
2514         if (flags)
2515                 err = __jbd2_journal_erase(journal, flags);
2516
2517         mutex_unlock(&journal->j_checkpoint_mutex);
2518         write_lock(&journal->j_state_lock);
2519         J_ASSERT(!journal->j_running_transaction);
2520         J_ASSERT(!journal->j_committing_transaction);
2521         J_ASSERT(!journal->j_checkpoint_transactions);
2522         J_ASSERT(journal->j_head == journal->j_tail);
2523         J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
2524         write_unlock(&journal->j_state_lock);
2525 out:
2526         return err;
2527 }
2528
2529 /**
2530  * jbd2_journal_wipe() - Wipe journal contents
2531  * @journal: Journal to act on.
2532  * @write: flag (see below)
2533  *
2534  * Wipe out all of the contents of a journal, safely.  This will produce
2535  * a warning if the journal contains any valid recovery information.
2536  * Must be called between journal_init_*() and jbd2_journal_load().
2537  *
2538  * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
2539  * we merely suppress recovery.
2540  */
2541
2542 int jbd2_journal_wipe(journal_t *journal, int write)
2543 {
2544         int err = 0;
2545
2546         J_ASSERT (!(journal->j_flags & JBD2_LOADED));
2547
2548         err = load_superblock(journal);
2549         if (err)
2550                 return err;
2551
2552         if (!journal->j_tail)
2553                 goto no_recovery;
2554
2555         printk(KERN_WARNING "JBD2: %s recovery information on journal\n",
2556                 write ? "Clearing" : "Ignoring");
2557
2558         err = jbd2_journal_skip_recovery(journal);
2559         if (write) {
2560                 /* Lock to make assertions happy... */
2561                 mutex_lock_io(&journal->j_checkpoint_mutex);
2562                 jbd2_mark_journal_empty(journal, REQ_SYNC | REQ_FUA);
2563                 mutex_unlock(&journal->j_checkpoint_mutex);
2564         }
2565
2566  no_recovery:
2567         return err;
2568 }
2569
2570 /**
2571  * jbd2_journal_abort () - Shutdown the journal immediately.
2572  * @journal: the journal to shutdown.
2573  * @errno:   an error number to record in the journal indicating
2574  *           the reason for the shutdown.
2575  *
2576  * Perform a complete, immediate shutdown of the ENTIRE
2577  * journal (not of a single transaction).  This operation cannot be
2578  * undone without closing and reopening the journal.
2579  *
2580  * The jbd2_journal_abort function is intended to support higher level error
2581  * recovery mechanisms such as the ext2/ext3 remount-readonly error
2582  * mode.
2583  *
2584  * Journal abort has very specific semantics.  Any existing dirty,
2585  * unjournaled buffers in the main filesystem will still be written to
2586  * disk by bdflush, but the journaling mechanism will be suspended
2587  * immediately and no further transaction commits will be honoured.
2588  *
2589  * Any dirty, journaled buffers will be written back to disk without
2590  * hitting the journal.  Atomicity cannot be guaranteed on an aborted
2591  * filesystem, but we _do_ attempt to leave as much data as possible
2592  * behind for fsck to use for cleanup.
2593  *
2594  * Any attempt to get a new transaction handle on a journal which is in
2595  * ABORT state will just result in an -EROFS error return.  A
2596  * jbd2_journal_stop on an existing handle will return -EIO if we have
2597  * entered abort state during the update.
2598  *
2599  * Recursive transactions are not disturbed by journal abort until the
2600  * final jbd2_journal_stop, which will receive the -EIO error.
2601  *
2602  * Finally, the jbd2_journal_abort call allows the caller to supply an errno
2603  * which will be recorded (if possible) in the journal superblock.  This
2604  * allows a client to record failure conditions in the middle of a
2605  * transaction without having to complete the transaction to record the
2606  * failure to disk.  ext3_error, for example, now uses this
2607  * functionality.
2608  *
2609  */
2610
2611 void jbd2_journal_abort(journal_t *journal, int errno)
2612 {
2613         transaction_t *transaction;
2614
2615         /*
2616          * Lock the aborting procedure until everything is done, this avoid
2617          * races between filesystem's error handling flow (e.g. ext4_abort()),
2618          * ensure panic after the error info is written into journal's
2619          * superblock.
2620          */
2621         mutex_lock(&journal->j_abort_mutex);
2622         /*
2623          * ESHUTDOWN always takes precedence because a file system check
2624          * caused by any other journal abort error is not required after
2625          * a shutdown triggered.
2626          */
2627         write_lock(&journal->j_state_lock);
2628         if (journal->j_flags & JBD2_ABORT) {
2629                 int old_errno = journal->j_errno;
2630
2631                 write_unlock(&journal->j_state_lock);
2632                 if (old_errno != -ESHUTDOWN && errno == -ESHUTDOWN) {
2633                         journal->j_errno = errno;
2634                         jbd2_journal_update_sb_errno(journal);
2635                 }
2636                 mutex_unlock(&journal->j_abort_mutex);
2637                 return;
2638         }
2639
2640         /*
2641          * Mark the abort as occurred and start current running transaction
2642          * to release all journaled buffer.
2643          */
2644         pr_err("Aborting journal on device %s.\n", journal->j_devname);
2645
2646         journal->j_flags |= JBD2_ABORT;
2647         journal->j_errno = errno;
2648         transaction = journal->j_running_transaction;
2649         if (transaction)
2650                 __jbd2_log_start_commit(journal, transaction->t_tid);
2651         write_unlock(&journal->j_state_lock);
2652
2653         /*
2654          * Record errno to the journal super block, so that fsck and jbd2
2655          * layer could realise that a filesystem check is needed.
2656          */
2657         jbd2_journal_update_sb_errno(journal);
2658         mutex_unlock(&journal->j_abort_mutex);
2659 }
2660
2661 /**
2662  * jbd2_journal_errno() - returns the journal's error state.
2663  * @journal: journal to examine.
2664  *
2665  * This is the errno number set with jbd2_journal_abort(), the last
2666  * time the journal was mounted - if the journal was stopped
2667  * without calling abort this will be 0.
2668  *
2669  * If the journal has been aborted on this mount time -EROFS will
2670  * be returned.
2671  */
2672 int jbd2_journal_errno(journal_t *journal)
2673 {
2674         int err;
2675
2676         read_lock(&journal->j_state_lock);
2677         if (journal->j_flags & JBD2_ABORT)
2678                 err = -EROFS;
2679         else
2680                 err = journal->j_errno;
2681         read_unlock(&journal->j_state_lock);
2682         return err;
2683 }
2684
2685 /**
2686  * jbd2_journal_clear_err() - clears the journal's error state
2687  * @journal: journal to act on.
2688  *
2689  * An error must be cleared or acked to take a FS out of readonly
2690  * mode.
2691  */
2692 int jbd2_journal_clear_err(journal_t *journal)
2693 {
2694         int err = 0;
2695
2696         write_lock(&journal->j_state_lock);
2697         if (journal->j_flags & JBD2_ABORT)
2698                 err = -EROFS;
2699         else
2700                 journal->j_errno = 0;
2701         write_unlock(&journal->j_state_lock);
2702         return err;
2703 }
2704
2705 /**
2706  * jbd2_journal_ack_err() - Ack journal err.
2707  * @journal: journal to act on.
2708  *
2709  * An error must be cleared or acked to take a FS out of readonly
2710  * mode.
2711  */
2712 void jbd2_journal_ack_err(journal_t *journal)
2713 {
2714         write_lock(&journal->j_state_lock);
2715         if (journal->j_errno)
2716                 journal->j_flags |= JBD2_ACK_ERR;
2717         write_unlock(&journal->j_state_lock);
2718 }
2719
2720 int jbd2_journal_blocks_per_page(struct inode *inode)
2721 {
2722         return 1 << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
2723 }
2724
2725 /*
2726  * helper functions to deal with 32 or 64bit block numbers.
2727  */
2728 size_t journal_tag_bytes(journal_t *journal)
2729 {
2730         size_t sz;
2731
2732         if (jbd2_has_feature_csum3(journal))
2733                 return sizeof(journal_block_tag3_t);
2734
2735         sz = sizeof(journal_block_tag_t);
2736
2737         if (jbd2_has_feature_csum2(journal))
2738                 sz += sizeof(__u16);
2739
2740         if (jbd2_has_feature_64bit(journal))
2741                 return sz;
2742         else
2743                 return sz - sizeof(__u32);
2744 }
2745
2746 /*
2747  * JBD memory management
2748  *
2749  * These functions are used to allocate block-sized chunks of memory
2750  * used for making copies of buffer_head data.  Very often it will be
2751  * page-sized chunks of data, but sometimes it will be in
2752  * sub-page-size chunks.  (For example, 16k pages on Power systems
2753  * with a 4k block file system.)  For blocks smaller than a page, we
2754  * use a SLAB allocator.  There are slab caches for each block size,
2755  * which are allocated at mount time, if necessary, and we only free
2756  * (all of) the slab caches when/if the jbd2 module is unloaded.  For
2757  * this reason we don't need to a mutex to protect access to
2758  * jbd2_slab[] allocating or releasing memory; only in
2759  * jbd2_journal_create_slab().
2760  */
2761 #define JBD2_MAX_SLABS 8
2762 static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS];
2763
2764 static const char *jbd2_slab_names[JBD2_MAX_SLABS] = {
2765         "jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k",
2766         "jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k"
2767 };
2768
2769
2770 static void jbd2_journal_destroy_slabs(void)
2771 {
2772         int i;
2773
2774         for (i = 0; i < JBD2_MAX_SLABS; i++) {
2775                 kmem_cache_destroy(jbd2_slab[i]);
2776                 jbd2_slab[i] = NULL;
2777         }
2778 }
2779
2780 static int jbd2_journal_create_slab(size_t size)
2781 {
2782         static DEFINE_MUTEX(jbd2_slab_create_mutex);
2783         int i = order_base_2(size) - 10;
2784         size_t slab_size;
2785
2786         if (size == PAGE_SIZE)
2787                 return 0;
2788
2789         if (i >= JBD2_MAX_SLABS)
2790                 return -EINVAL;
2791
2792         if (unlikely(i < 0))
2793                 i = 0;
2794         mutex_lock(&jbd2_slab_create_mutex);
2795         if (jbd2_slab[i]) {
2796                 mutex_unlock(&jbd2_slab_create_mutex);
2797                 return 0;       /* Already created */
2798         }
2799
2800         slab_size = 1 << (i+10);
2801         jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size,
2802                                          slab_size, 0, NULL);
2803         mutex_unlock(&jbd2_slab_create_mutex);
2804         if (!jbd2_slab[i]) {
2805                 printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n");
2806                 return -ENOMEM;
2807         }
2808         return 0;
2809 }
2810
2811 static struct kmem_cache *get_slab(size_t size)
2812 {
2813         int i = order_base_2(size) - 10;
2814
2815         BUG_ON(i >= JBD2_MAX_SLABS);
2816         if (unlikely(i < 0))
2817                 i = 0;
2818         BUG_ON(jbd2_slab[i] == NULL);
2819         return jbd2_slab[i];
2820 }
2821
2822 void *jbd2_alloc(size_t size, gfp_t flags)
2823 {
2824         void *ptr;
2825
2826         BUG_ON(size & (size-1)); /* Must be a power of 2 */
2827
2828         if (size < PAGE_SIZE)
2829                 ptr = kmem_cache_alloc(get_slab(size), flags);
2830         else
2831                 ptr = (void *)__get_free_pages(flags, get_order(size));
2832
2833         /* Check alignment; SLUB has gotten this wrong in the past,
2834          * and this can lead to user data corruption! */
2835         BUG_ON(((unsigned long) ptr) & (size-1));
2836
2837         return ptr;
2838 }
2839
2840 void jbd2_free(void *ptr, size_t size)
2841 {
2842         if (size < PAGE_SIZE)
2843                 kmem_cache_free(get_slab(size), ptr);
2844         else
2845                 free_pages((unsigned long)ptr, get_order(size));
2846 };
2847
2848 /*
2849  * Journal_head storage management
2850  */
2851 static struct kmem_cache *jbd2_journal_head_cache;
2852 #ifdef CONFIG_JBD2_DEBUG
2853 static atomic_t nr_journal_heads = ATOMIC_INIT(0);
2854 #endif
2855
2856 static int __init jbd2_journal_init_journal_head_cache(void)
2857 {
2858         J_ASSERT(!jbd2_journal_head_cache);
2859         jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
2860                                 sizeof(struct journal_head),
2861                                 0,              /* offset */
2862                                 SLAB_TEMPORARY | SLAB_TYPESAFE_BY_RCU,
2863                                 NULL);          /* ctor */
2864         if (!jbd2_journal_head_cache) {
2865                 printk(KERN_EMERG "JBD2: no memory for journal_head cache\n");
2866                 return -ENOMEM;
2867         }
2868         return 0;
2869 }
2870
2871 static void jbd2_journal_destroy_journal_head_cache(void)
2872 {
2873         kmem_cache_destroy(jbd2_journal_head_cache);
2874         jbd2_journal_head_cache = NULL;
2875 }
2876
2877 /*
2878  * journal_head splicing and dicing
2879  */
2880 static struct journal_head *journal_alloc_journal_head(void)
2881 {
2882         struct journal_head *ret;
2883
2884 #ifdef CONFIG_JBD2_DEBUG
2885         atomic_inc(&nr_journal_heads);
2886 #endif
2887         ret = kmem_cache_zalloc(jbd2_journal_head_cache, GFP_NOFS);
2888         if (!ret) {
2889                 jbd_debug(1, "out of memory for journal_head\n");
2890                 pr_notice_ratelimited("ENOMEM in %s, retrying.\n", __func__);
2891                 ret = kmem_cache_zalloc(jbd2_journal_head_cache,
2892                                 GFP_NOFS | __GFP_NOFAIL);
2893         }
2894         if (ret)
2895                 spin_lock_init(&ret->b_state_lock);
2896         return ret;
2897 }
2898
2899 static void journal_free_journal_head(struct journal_head *jh)
2900 {
2901 #ifdef CONFIG_JBD2_DEBUG
2902         atomic_dec(&nr_journal_heads);
2903         memset(jh, JBD2_POISON_FREE, sizeof(*jh));
2904 #endif
2905         kmem_cache_free(jbd2_journal_head_cache, jh);
2906 }
2907
2908 /*
2909  * A journal_head is attached to a buffer_head whenever JBD has an
2910  * interest in the buffer.
2911  *
2912  * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
2913  * is set.  This bit is tested in core kernel code where we need to take
2914  * JBD-specific actions.  Testing the zeroness of ->b_private is not reliable
2915  * there.
2916  *
2917  * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
2918  *
2919  * When a buffer has its BH_JBD bit set it is immune from being released by
2920  * core kernel code, mainly via ->b_count.
2921  *
2922  * A journal_head is detached from its buffer_head when the journal_head's
2923  * b_jcount reaches zero. Running transaction (b_transaction) and checkpoint
2924  * transaction (b_cp_transaction) hold their references to b_jcount.
2925  *
2926  * Various places in the kernel want to attach a journal_head to a buffer_head
2927  * _before_ attaching the journal_head to a transaction.  To protect the
2928  * journal_head in this situation, jbd2_journal_add_journal_head elevates the
2929  * journal_head's b_jcount refcount by one.  The caller must call
2930  * jbd2_journal_put_journal_head() to undo this.
2931  *
2932  * So the typical usage would be:
2933  *
2934  *      (Attach a journal_head if needed.  Increments b_jcount)
2935  *      struct journal_head *jh = jbd2_journal_add_journal_head(bh);
2936  *      ...
2937  *      (Get another reference for transaction)
2938  *      jbd2_journal_grab_journal_head(bh);
2939  *      jh->b_transaction = xxx;
2940  *      (Put original reference)
2941  *      jbd2_journal_put_journal_head(jh);
2942  */
2943
2944 /*
2945  * Give a buffer_head a journal_head.
2946  *
2947  * May sleep.
2948  */
2949 struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
2950 {
2951         struct journal_head *jh;
2952         struct journal_head *new_jh = NULL;
2953
2954 repeat:
2955         if (!buffer_jbd(bh))
2956                 new_jh = journal_alloc_journal_head();
2957
2958         jbd_lock_bh_journal_head(bh);
2959         if (buffer_jbd(bh)) {
2960                 jh = bh2jh(bh);
2961         } else {
2962                 J_ASSERT_BH(bh,
2963                         (atomic_read(&bh->b_count) > 0) ||
2964                         (bh->b_page && bh->b_page->mapping));
2965
2966                 if (!new_jh) {
2967                         jbd_unlock_bh_journal_head(bh);
2968                         goto repeat;
2969                 }
2970
2971                 jh = new_jh;
2972                 new_jh = NULL;          /* We consumed it */
2973                 set_buffer_jbd(bh);
2974                 bh->b_private = jh;
2975                 jh->b_bh = bh;
2976                 get_bh(bh);
2977                 BUFFER_TRACE(bh, "added journal_head");
2978         }
2979         jh->b_jcount++;
2980         jbd_unlock_bh_journal_head(bh);
2981         if (new_jh)
2982                 journal_free_journal_head(new_jh);
2983         return bh->b_private;
2984 }
2985
2986 /*
2987  * Grab a ref against this buffer_head's journal_head.  If it ended up not
2988  * having a journal_head, return NULL
2989  */
2990 struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh)
2991 {
2992         struct journal_head *jh = NULL;
2993
2994         jbd_lock_bh_journal_head(bh);
2995         if (buffer_jbd(bh)) {
2996                 jh = bh2jh(bh);
2997                 jh->b_jcount++;
2998         }
2999         jbd_unlock_bh_journal_head(bh);
3000         return jh;
3001 }
3002
3003 static void __journal_remove_journal_head(struct buffer_head *bh)
3004 {
3005         struct journal_head *jh = bh2jh(bh);
3006
3007         J_ASSERT_JH(jh, jh->b_transaction == NULL);
3008         J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
3009         J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
3010         J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
3011         J_ASSERT_BH(bh, buffer_jbd(bh));
3012         J_ASSERT_BH(bh, jh2bh(jh) == bh);
3013         BUFFER_TRACE(bh, "remove journal_head");
3014
3015         /* Unlink before dropping the lock */
3016         bh->b_private = NULL;
3017         jh->b_bh = NULL;        /* debug, really */
3018         clear_buffer_jbd(bh);
3019 }
3020
3021 static void journal_release_journal_head(struct journal_head *jh, size_t b_size)
3022 {
3023         if (jh->b_frozen_data) {
3024                 printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
3025                 jbd2_free(jh->b_frozen_data, b_size);
3026         }
3027         if (jh->b_committed_data) {
3028                 printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
3029                 jbd2_free(jh->b_committed_data, b_size);
3030         }
3031         journal_free_journal_head(jh);
3032 }
3033
3034 /*
3035  * Drop a reference on the passed journal_head.  If it fell to zero then
3036  * release the journal_head from the buffer_head.
3037  */
3038 void jbd2_journal_put_journal_head(struct journal_head *jh)
3039 {
3040         struct buffer_head *bh = jh2bh(jh);
3041
3042         jbd_lock_bh_journal_head(bh);
3043         J_ASSERT_JH(jh, jh->b_jcount > 0);
3044         --jh->b_jcount;
3045         if (!jh->b_jcount) {
3046                 __journal_remove_journal_head(bh);
3047                 jbd_unlock_bh_journal_head(bh);
3048                 journal_release_journal_head(jh, bh->b_size);
3049                 __brelse(bh);
3050         } else {
3051                 jbd_unlock_bh_journal_head(bh);
3052         }
3053 }
3054
3055 /*
3056  * Initialize jbd inode head
3057  */
3058 void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode)
3059 {
3060         jinode->i_transaction = NULL;
3061         jinode->i_next_transaction = NULL;
3062         jinode->i_vfs_inode = inode;
3063         jinode->i_flags = 0;
3064         jinode->i_dirty_start = 0;
3065         jinode->i_dirty_end = 0;
3066         INIT_LIST_HEAD(&jinode->i_list);
3067 }
3068
3069 /*
3070  * Function to be called before we start removing inode from memory (i.e.,
3071  * clear_inode() is a fine place to be called from). It removes inode from
3072  * transaction's lists.
3073  */
3074 void jbd2_journal_release_jbd_inode(journal_t *journal,
3075                                     struct jbd2_inode *jinode)
3076 {
3077         if (!journal)
3078                 return;
3079 restart:
3080         spin_lock(&journal->j_list_lock);
3081         /* Is commit writing out inode - we have to wait */
3082         if (jinode->i_flags & JI_COMMIT_RUNNING) {
3083                 wait_queue_head_t *wq;
3084                 DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
3085                 wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
3086                 prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
3087                 spin_unlock(&journal->j_list_lock);
3088                 schedule();
3089                 finish_wait(wq, &wait.wq_entry);
3090                 goto restart;
3091         }
3092
3093         if (jinode->i_transaction) {
3094                 list_del(&jinode->i_list);
3095                 jinode->i_transaction = NULL;
3096         }
3097         spin_unlock(&journal->j_list_lock);
3098 }
3099
3100
3101 #ifdef CONFIG_PROC_FS
3102
3103 #define JBD2_STATS_PROC_NAME "fs/jbd2"
3104
3105 static void __init jbd2_create_jbd_stats_proc_entry(void)
3106 {
3107         proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL);
3108 }
3109
3110 static void __exit jbd2_remove_jbd_stats_proc_entry(void)
3111 {
3112         if (proc_jbd2_stats)
3113                 remove_proc_entry(JBD2_STATS_PROC_NAME, NULL);
3114 }
3115
3116 #else
3117
3118 #define jbd2_create_jbd_stats_proc_entry() do {} while (0)
3119 #define jbd2_remove_jbd_stats_proc_entry() do {} while (0)
3120
3121 #endif
3122
3123 struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
3124
3125 static int __init jbd2_journal_init_inode_cache(void)
3126 {
3127         J_ASSERT(!jbd2_inode_cache);
3128         jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0);
3129         if (!jbd2_inode_cache) {
3130                 pr_emerg("JBD2: failed to create inode cache\n");
3131                 return -ENOMEM;
3132         }
3133         return 0;
3134 }
3135
3136 static int __init jbd2_journal_init_handle_cache(void)
3137 {
3138         J_ASSERT(!jbd2_handle_cache);
3139         jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
3140         if (!jbd2_handle_cache) {
3141                 printk(KERN_EMERG "JBD2: failed to create handle cache\n");
3142                 return -ENOMEM;
3143         }
3144         return 0;
3145 }
3146
3147 static void jbd2_journal_destroy_inode_cache(void)
3148 {
3149         kmem_cache_destroy(jbd2_inode_cache);
3150         jbd2_inode_cache = NULL;
3151 }
3152
3153 static void jbd2_journal_destroy_handle_cache(void)
3154 {
3155         kmem_cache_destroy(jbd2_handle_cache);
3156         jbd2_handle_cache = NULL;
3157 }
3158
3159 /*
3160  * Module startup and shutdown
3161  */
3162
3163 static int __init journal_init_caches(void)
3164 {
3165         int ret;
3166
3167         ret = jbd2_journal_init_revoke_record_cache();
3168         if (ret == 0)
3169                 ret = jbd2_journal_init_revoke_table_cache();
3170         if (ret == 0)
3171                 ret = jbd2_journal_init_journal_head_cache();
3172         if (ret == 0)
3173                 ret = jbd2_journal_init_handle_cache();
3174         if (ret == 0)
3175                 ret = jbd2_journal_init_inode_cache();
3176         if (ret == 0)
3177                 ret = jbd2_journal_init_transaction_cache();
3178         return ret;
3179 }
3180
3181 static void jbd2_journal_destroy_caches(void)
3182 {
3183         jbd2_journal_destroy_revoke_record_cache();
3184         jbd2_journal_destroy_revoke_table_cache();
3185         jbd2_journal_destroy_journal_head_cache();
3186         jbd2_journal_destroy_handle_cache();
3187         jbd2_journal_destroy_inode_cache();
3188         jbd2_journal_destroy_transaction_cache();
3189         jbd2_journal_destroy_slabs();
3190 }
3191
3192 static int __init journal_init(void)
3193 {
3194         int ret;
3195
3196         BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
3197
3198         ret = journal_init_caches();
3199         if (ret == 0) {
3200                 jbd2_create_jbd_stats_proc_entry();
3201         } else {
3202                 jbd2_journal_destroy_caches();
3203         }
3204         return ret;
3205 }
3206
3207 static void __exit journal_exit(void)
3208 {
3209 #ifdef CONFIG_JBD2_DEBUG
3210         int n = atomic_read(&nr_journal_heads);
3211         if (n)
3212                 printk(KERN_ERR "JBD2: leaked %d journal_heads!\n", n);
3213 #endif
3214         jbd2_remove_jbd_stats_proc_entry();
3215         jbd2_journal_destroy_caches();
3216 }
3217
3218 MODULE_LICENSE("GPL");
3219 module_init(journal_init);
3220 module_exit(journal_exit);
3221