linux/fs/jbd2/journal.c
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   1/*
   2 * linux/fs/jbd2/journal.c
   3 *
   4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
   5 *
   6 * Copyright 1998 Red Hat corp --- All Rights Reserved
   7 *
   8 * This file is part of the Linux kernel and is made available under
   9 * the terms of the GNU General Public License, version 2, or at your
  10 * option, any later version, incorporated herein by reference.
  11 *
  12 * Generic filesystem journal-writing code; part of the ext2fs
  13 * journaling system.
  14 *
  15 * This file manages journals: areas of disk reserved for logging
  16 * transactional updates.  This includes the kernel journaling thread
  17 * which is responsible for scheduling updates to the log.
  18 *
  19 * We do not actually manage the physical storage of the journal in this
  20 * file: that is left to a per-journal policy function, which allows us
  21 * to store the journal within a filesystem-specified area for ext2
  22 * journaling (ext2 can use a reserved inode for storing the log).
  23 */
  24
  25#include <linux/module.h>
  26#include <linux/time.h>
  27#include <linux/fs.h>
  28#include <linux/jbd2.h>
  29#include <linux/errno.h>
  30#include <linux/slab.h>
  31#include <linux/init.h>
  32#include <linux/mm.h>
  33#include <linux/freezer.h>
  34#include <linux/pagemap.h>
  35#include <linux/kthread.h>
  36#include <linux/poison.h>
  37#include <linux/proc_fs.h>
  38#include <linux/debugfs.h>
  39#include <linux/seq_file.h>
  40#include <linux/math64.h>
  41#include <linux/hash.h>
  42#include <linux/log2.h>
  43#include <linux/vmalloc.h>
  44#include <linux/backing-dev.h>
  45#include <linux/bitops.h>
  46#include <linux/ratelimit.h>
  47
  48#define CREATE_TRACE_POINTS
  49#include <trace/events/jbd2.h>
  50
  51#include <asm/uaccess.h>
  52#include <asm/page.h>
  53
  54EXPORT_SYMBOL(jbd2_journal_extend);
  55EXPORT_SYMBOL(jbd2_journal_stop);
  56EXPORT_SYMBOL(jbd2_journal_lock_updates);
  57EXPORT_SYMBOL(jbd2_journal_unlock_updates);
  58EXPORT_SYMBOL(jbd2_journal_get_write_access);
  59EXPORT_SYMBOL(jbd2_journal_get_create_access);
  60EXPORT_SYMBOL(jbd2_journal_get_undo_access);
  61EXPORT_SYMBOL(jbd2_journal_set_triggers);
  62EXPORT_SYMBOL(jbd2_journal_dirty_metadata);
  63EXPORT_SYMBOL(jbd2_journal_release_buffer);
  64EXPORT_SYMBOL(jbd2_journal_forget);
  65#if 0
  66EXPORT_SYMBOL(journal_sync_buffer);
  67#endif
  68EXPORT_SYMBOL(jbd2_journal_flush);
  69EXPORT_SYMBOL(jbd2_journal_revoke);
  70
  71EXPORT_SYMBOL(jbd2_journal_init_dev);
  72EXPORT_SYMBOL(jbd2_journal_init_inode);
  73EXPORT_SYMBOL(jbd2_journal_check_used_features);
  74EXPORT_SYMBOL(jbd2_journal_check_available_features);
  75EXPORT_SYMBOL(jbd2_journal_set_features);
  76EXPORT_SYMBOL(jbd2_journal_load);
  77EXPORT_SYMBOL(jbd2_journal_destroy);
  78EXPORT_SYMBOL(jbd2_journal_abort);
  79EXPORT_SYMBOL(jbd2_journal_errno);
  80EXPORT_SYMBOL(jbd2_journal_ack_err);
  81EXPORT_SYMBOL(jbd2_journal_clear_err);
  82EXPORT_SYMBOL(jbd2_log_wait_commit);
  83EXPORT_SYMBOL(jbd2_log_start_commit);
  84EXPORT_SYMBOL(jbd2_journal_start_commit);
  85EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
  86EXPORT_SYMBOL(jbd2_journal_wipe);
  87EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
  88EXPORT_SYMBOL(jbd2_journal_invalidatepage);
  89EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
  90EXPORT_SYMBOL(jbd2_journal_force_commit);
  91EXPORT_SYMBOL(jbd2_journal_file_inode);
  92EXPORT_SYMBOL(jbd2_journal_init_jbd_inode);
  93EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
  94EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
  95EXPORT_SYMBOL(jbd2_inode_cache);
  96
  97static void __journal_abort_soft (journal_t *journal, int errno);
  98static int jbd2_journal_create_slab(size_t slab_size);
  99
 100/* Checksumming functions */
 101int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb)
 102{
 103        if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
 104                return 1;
 105
 106        return sb->s_checksum_type == JBD2_CRC32C_CHKSUM;
 107}
 108
 109static __u32 jbd2_superblock_csum(journal_t *j, journal_superblock_t *sb)
 110{
 111        __u32 csum, old_csum;
 112
 113        old_csum = sb->s_checksum;
 114        sb->s_checksum = 0;
 115        csum = jbd2_chksum(j, ~0, (char *)sb, sizeof(journal_superblock_t));
 116        sb->s_checksum = old_csum;
 117
 118        return cpu_to_be32(csum);
 119}
 120
 121int jbd2_superblock_csum_verify(journal_t *j, journal_superblock_t *sb)
 122{
 123        if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
 124                return 1;
 125
 126        return sb->s_checksum == jbd2_superblock_csum(j, sb);
 127}
 128
 129void jbd2_superblock_csum_set(journal_t *j, journal_superblock_t *sb)
 130{
 131        if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
 132                return;
 133
 134        sb->s_checksum = jbd2_superblock_csum(j, sb);
 135}
 136
 137/*
 138 * Helper function used to manage commit timeouts
 139 */
 140
 141static void commit_timeout(unsigned long __data)
 142{
 143        struct task_struct * p = (struct task_struct *) __data;
 144
 145        wake_up_process(p);
 146}
 147
 148/*
 149 * kjournald2: The main thread function used to manage a logging device
 150 * journal.
 151 *
 152 * This kernel thread is responsible for two things:
 153 *
 154 * 1) COMMIT:  Every so often we need to commit the current state of the
 155 *    filesystem to disk.  The journal thread is responsible for writing
 156 *    all of the metadata buffers to disk.
 157 *
 158 * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
 159 *    of the data in that part of the log has been rewritten elsewhere on
 160 *    the disk.  Flushing these old buffers to reclaim space in the log is
 161 *    known as checkpointing, and this thread is responsible for that job.
 162 */
 163
 164static int kjournald2(void *arg)
 165{
 166        journal_t *journal = arg;
 167        transaction_t *transaction;
 168
 169        /*
 170         * Set up an interval timer which can be used to trigger a commit wakeup
 171         * after the commit interval expires
 172         */
 173        setup_timer(&journal->j_commit_timer, commit_timeout,
 174                        (unsigned long)current);
 175
 176        set_freezable();
 177
 178        /* Record that the journal thread is running */
 179        journal->j_task = current;
 180        wake_up(&journal->j_wait_done_commit);
 181
 182        /*
 183         * And now, wait forever for commit wakeup events.
 184         */
 185        write_lock(&journal->j_state_lock);
 186
 187loop:
 188        if (journal->j_flags & JBD2_UNMOUNT)
 189                goto end_loop;
 190
 191        jbd_debug(1, "commit_sequence=%d, commit_request=%d\n",
 192                journal->j_commit_sequence, journal->j_commit_request);
 193
 194        if (journal->j_commit_sequence != journal->j_commit_request) {
 195                jbd_debug(1, "OK, requests differ\n");
 196                write_unlock(&journal->j_state_lock);
 197                del_timer_sync(&journal->j_commit_timer);
 198                jbd2_journal_commit_transaction(journal);
 199                write_lock(&journal->j_state_lock);
 200                goto loop;
 201        }
 202
 203        wake_up(&journal->j_wait_done_commit);
 204        if (freezing(current)) {
 205                /*
 206                 * The simpler the better. Flushing journal isn't a
 207                 * good idea, because that depends on threads that may
 208                 * be already stopped.
 209                 */
 210                jbd_debug(1, "Now suspending kjournald2\n");
 211                write_unlock(&journal->j_state_lock);
 212                try_to_freeze();
 213                write_lock(&journal->j_state_lock);
 214        } else {
 215                /*
 216                 * We assume on resume that commits are already there,
 217                 * so we don't sleep
 218                 */
 219                DEFINE_WAIT(wait);
 220                int should_sleep = 1;
 221
 222                prepare_to_wait(&journal->j_wait_commit, &wait,
 223                                TASK_INTERRUPTIBLE);
 224                if (journal->j_commit_sequence != journal->j_commit_request)
 225                        should_sleep = 0;
 226                transaction = journal->j_running_transaction;
 227                if (transaction && time_after_eq(jiffies,
 228                                                transaction->t_expires))
 229                        should_sleep = 0;
 230                if (journal->j_flags & JBD2_UNMOUNT)
 231                        should_sleep = 0;
 232                if (should_sleep) {
 233                        write_unlock(&journal->j_state_lock);
 234                        schedule();
 235                        write_lock(&journal->j_state_lock);
 236                }
 237                finish_wait(&journal->j_wait_commit, &wait);
 238        }
 239
 240        jbd_debug(1, "kjournald2 wakes\n");
 241
 242        /*
 243         * Were we woken up by a commit wakeup event?
 244         */
 245        transaction = journal->j_running_transaction;
 246        if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
 247                journal->j_commit_request = transaction->t_tid;
 248                jbd_debug(1, "woke because of timeout\n");
 249        }
 250        goto loop;
 251
 252end_loop:
 253        write_unlock(&journal->j_state_lock);
 254        del_timer_sync(&journal->j_commit_timer);
 255        journal->j_task = NULL;
 256        wake_up(&journal->j_wait_done_commit);
 257        jbd_debug(1, "Journal thread exiting.\n");
 258        return 0;
 259}
 260
 261static int jbd2_journal_start_thread(journal_t *journal)
 262{
 263        struct task_struct *t;
 264
 265        t = kthread_run(kjournald2, journal, "jbd2/%s",
 266                        journal->j_devname);
 267        if (IS_ERR(t))
 268                return PTR_ERR(t);
 269
 270        wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
 271        return 0;
 272}
 273
 274static void journal_kill_thread(journal_t *journal)
 275{
 276        write_lock(&journal->j_state_lock);
 277        journal->j_flags |= JBD2_UNMOUNT;
 278
 279        while (journal->j_task) {
 280                wake_up(&journal->j_wait_commit);
 281                write_unlock(&journal->j_state_lock);
 282                wait_event(journal->j_wait_done_commit, journal->j_task == NULL);
 283                write_lock(&journal->j_state_lock);
 284        }
 285        write_unlock(&journal->j_state_lock);
 286}
 287
 288/*
 289 * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
 290 *
 291 * Writes a metadata buffer to a given disk block.  The actual IO is not
 292 * performed but a new buffer_head is constructed which labels the data
 293 * to be written with the correct destination disk block.
 294 *
 295 * Any magic-number escaping which needs to be done will cause a
 296 * copy-out here.  If the buffer happens to start with the
 297 * JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the
 298 * magic number is only written to the log for descripter blocks.  In
 299 * this case, we copy the data and replace the first word with 0, and we
 300 * return a result code which indicates that this buffer needs to be
 301 * marked as an escaped buffer in the corresponding log descriptor
 302 * block.  The missing word can then be restored when the block is read
 303 * during recovery.
 304 *
 305 * If the source buffer has already been modified by a new transaction
 306 * since we took the last commit snapshot, we use the frozen copy of
 307 * that data for IO.  If we end up using the existing buffer_head's data
 308 * for the write, then we *have* to lock the buffer to prevent anyone
 309 * else from using and possibly modifying it while the IO is in
 310 * progress.
 311 *
 312 * The function returns a pointer to the buffer_heads to be used for IO.
 313 *
 314 * We assume that the journal has already been locked in this function.
 315 *
 316 * Return value:
 317 *  <0: Error
 318 * >=0: Finished OK
 319 *
 320 * On success:
 321 * Bit 0 set == escape performed on the data
 322 * Bit 1 set == buffer copy-out performed (kfree the data after IO)
 323 */
 324
 325int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
 326                                  struct journal_head  *jh_in,
 327                                  struct journal_head **jh_out,
 328                                  unsigned long long blocknr)
 329{
 330        int need_copy_out = 0;
 331        int done_copy_out = 0;
 332        int do_escape = 0;
 333        char *mapped_data;
 334        struct buffer_head *new_bh;
 335        struct journal_head *new_jh;
 336        struct page *new_page;
 337        unsigned int new_offset;
 338        struct buffer_head *bh_in = jh2bh(jh_in);
 339        journal_t *journal = transaction->t_journal;
 340
 341        /*
 342         * The buffer really shouldn't be locked: only the current committing
 343         * transaction is allowed to write it, so nobody else is allowed
 344         * to do any IO.
 345         *
 346         * akpm: except if we're journalling data, and write() output is
 347         * also part of a shared mapping, and another thread has
 348         * decided to launch a writepage() against this buffer.
 349         */
 350        J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
 351
 352retry_alloc:
 353        new_bh = alloc_buffer_head(GFP_NOFS);
 354        if (!new_bh) {
 355                /*
 356                 * Failure is not an option, but __GFP_NOFAIL is going
 357                 * away; so we retry ourselves here.
 358                 */
 359                congestion_wait(BLK_RW_ASYNC, HZ/50);
 360                goto retry_alloc;
 361        }
 362
 363        /* keep subsequent assertions sane */
 364        new_bh->b_state = 0;
 365        init_buffer(new_bh, NULL, NULL);
 366        atomic_set(&new_bh->b_count, 1);
 367        new_jh = jbd2_journal_add_journal_head(new_bh); /* This sleeps */
 368
 369        /*
 370         * If a new transaction has already done a buffer copy-out, then
 371         * we use that version of the data for the commit.
 372         */
 373        jbd_lock_bh_state(bh_in);
 374repeat:
 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                jbd_unlock_bh_state(bh_in);
 412                tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS);
 413                if (!tmp) {
 414                        jbd2_journal_put_journal_head(new_jh);
 415                        return -ENOMEM;
 416                }
 417                jbd_lock_bh_state(bh_in);
 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, jh2bh(jh_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_jh->b_transaction = NULL;
 452        new_bh->b_size = jh2bh(jh_in)->b_size;
 453        new_bh->b_bdev = transaction->t_journal->j_dev;
 454        new_bh->b_blocknr = blocknr;
 455        set_buffer_mapped(new_bh);
 456        set_buffer_dirty(new_bh);
 457
 458        *jh_out = new_jh;
 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        jbd_unlock_bh_state(bh_in);
 470
 471        JBUFFER_TRACE(new_jh, "file as BJ_IO");
 472        jbd2_journal_file_buffer(new_jh, transaction, BJ_IO);
 473
 474        return do_escape | (done_copy_out << 1);
 475}
 476
 477/*
 478 * Allocation code for the journal file.  Manage the space left in the
 479 * journal, so that we can begin checkpointing when appropriate.
 480 */
 481
 482/*
 483 * __jbd2_log_space_left: Return the number of free blocks left in the journal.
 484 *
 485 * Called with the journal already locked.
 486 *
 487 * Called under j_state_lock
 488 */
 489
 490int __jbd2_log_space_left(journal_t *journal)
 491{
 492        int left = journal->j_free;
 493
 494        /* assert_spin_locked(&journal->j_state_lock); */
 495
 496        /*
 497         * Be pessimistic here about the number of those free blocks which
 498         * might be required for log descriptor control blocks.
 499         */
 500
 501#define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */
 502
 503        left -= MIN_LOG_RESERVED_BLOCKS;
 504
 505        if (left <= 0)
 506                return 0;
 507        left -= (left >> 3);
 508        return left;
 509}
 510
 511/*
 512 * Called with j_state_lock locked for writing.
 513 * Returns true if a transaction commit was started.
 514 */
 515int __jbd2_log_start_commit(journal_t *journal, tid_t target)
 516{
 517        /*
 518         * The only transaction we can possibly wait upon is the
 519         * currently running transaction (if it exists).  Otherwise,
 520         * the target tid must be an old one.
 521         */
 522        if (journal->j_running_transaction &&
 523            journal->j_running_transaction->t_tid == target) {
 524                /*
 525                 * We want a new commit: OK, mark the request and wakeup the
 526                 * commit thread.  We do _not_ do the commit ourselves.
 527                 */
 528
 529                journal->j_commit_request = target;
 530                jbd_debug(1, "JBD2: requesting commit %d/%d\n",
 531                          journal->j_commit_request,
 532                          journal->j_commit_sequence);
 533                wake_up(&journal->j_wait_commit);
 534                return 1;
 535        } else if (!tid_geq(journal->j_commit_request, target))
 536                /* This should never happen, but if it does, preserve
 537                   the evidence before kjournald goes into a loop and
 538                   increments j_commit_sequence beyond all recognition. */
 539                WARN_ONCE(1, "JBD2: bad log_start_commit: %u %u %u %u\n",
 540                          journal->j_commit_request,
 541                          journal->j_commit_sequence,
 542                          target, journal->j_running_transaction ? 
 543                          journal->j_running_transaction->t_tid : 0);
 544        return 0;
 545}
 546
 547int jbd2_log_start_commit(journal_t *journal, tid_t tid)
 548{
 549        int ret;
 550
 551        write_lock(&journal->j_state_lock);
 552        ret = __jbd2_log_start_commit(journal, tid);
 553        write_unlock(&journal->j_state_lock);
 554        return ret;
 555}
 556
 557/*
 558 * Force and wait upon a commit if the calling process is not within
 559 * transaction.  This is used for forcing out undo-protected data which contains
 560 * bitmaps, when the fs is running out of space.
 561 *
 562 * We can only force the running transaction if we don't have an active handle;
 563 * otherwise, we will deadlock.
 564 *
 565 * Returns true if a transaction was started.
 566 */
 567int jbd2_journal_force_commit_nested(journal_t *journal)
 568{
 569        transaction_t *transaction = NULL;
 570        tid_t tid;
 571        int need_to_start = 0;
 572
 573        read_lock(&journal->j_state_lock);
 574        if (journal->j_running_transaction && !current->journal_info) {
 575                transaction = journal->j_running_transaction;
 576                if (!tid_geq(journal->j_commit_request, transaction->t_tid))
 577                        need_to_start = 1;
 578        } else if (journal->j_committing_transaction)
 579                transaction = journal->j_committing_transaction;
 580
 581        if (!transaction) {
 582                read_unlock(&journal->j_state_lock);
 583                return 0;       /* Nothing to retry */
 584        }
 585
 586        tid = transaction->t_tid;
 587        read_unlock(&journal->j_state_lock);
 588        if (need_to_start)
 589                jbd2_log_start_commit(journal, tid);
 590        jbd2_log_wait_commit(journal, tid);
 591        return 1;
 592}
 593
 594/*
 595 * Start a commit of the current running transaction (if any).  Returns true
 596 * if a transaction is going to be committed (or is currently already
 597 * committing), and fills its tid in at *ptid
 598 */
 599int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid)
 600{
 601        int ret = 0;
 602
 603        write_lock(&journal->j_state_lock);
 604        if (journal->j_running_transaction) {
 605                tid_t tid = journal->j_running_transaction->t_tid;
 606
 607                __jbd2_log_start_commit(journal, tid);
 608                /* There's a running transaction and we've just made sure
 609                 * it's commit has been scheduled. */
 610                if (ptid)
 611                        *ptid = tid;
 612                ret = 1;
 613        } else if (journal->j_committing_transaction) {
 614                /*
 615                 * If commit has been started, then we have to wait for
 616                 * completion of that transaction.
 617                 */
 618                if (ptid)
 619                        *ptid = journal->j_committing_transaction->t_tid;
 620                ret = 1;
 621        }
 622        write_unlock(&journal->j_state_lock);
 623        return ret;
 624}
 625
 626/*
 627 * Return 1 if a given transaction has not yet sent barrier request
 628 * connected with a transaction commit. If 0 is returned, transaction
 629 * may or may not have sent the barrier. Used to avoid sending barrier
 630 * twice in common cases.
 631 */
 632int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid)
 633{
 634        int ret = 0;
 635        transaction_t *commit_trans;
 636
 637        if (!(journal->j_flags & JBD2_BARRIER))
 638                return 0;
 639        read_lock(&journal->j_state_lock);
 640        /* Transaction already committed? */
 641        if (tid_geq(journal->j_commit_sequence, tid))
 642                goto out;
 643        commit_trans = journal->j_committing_transaction;
 644        if (!commit_trans || commit_trans->t_tid != tid) {
 645                ret = 1;
 646                goto out;
 647        }
 648        /*
 649         * Transaction is being committed and we already proceeded to
 650         * submitting a flush to fs partition?
 651         */
 652        if (journal->j_fs_dev != journal->j_dev) {
 653                if (!commit_trans->t_need_data_flush ||
 654                    commit_trans->t_state >= T_COMMIT_DFLUSH)
 655                        goto out;
 656        } else {
 657                if (commit_trans->t_state >= T_COMMIT_JFLUSH)
 658                        goto out;
 659        }
 660        ret = 1;
 661out:
 662        read_unlock(&journal->j_state_lock);
 663        return ret;
 664}
 665EXPORT_SYMBOL(jbd2_trans_will_send_data_barrier);
 666
 667/*
 668 * Wait for a specified commit to complete.
 669 * The caller may not hold the journal lock.
 670 */
 671int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
 672{
 673        int err = 0;
 674
 675        read_lock(&journal->j_state_lock);
 676#ifdef CONFIG_JBD2_DEBUG
 677        if (!tid_geq(journal->j_commit_request, tid)) {
 678                printk(KERN_EMERG
 679                       "%s: error: j_commit_request=%d, tid=%d\n",
 680                       __func__, journal->j_commit_request, tid);
 681        }
 682#endif
 683        while (tid_gt(tid, journal->j_commit_sequence)) {
 684                jbd_debug(1, "JBD2: want %d, j_commit_sequence=%d\n",
 685                                  tid, journal->j_commit_sequence);
 686                wake_up(&journal->j_wait_commit);
 687                read_unlock(&journal->j_state_lock);
 688                wait_event(journal->j_wait_done_commit,
 689                                !tid_gt(tid, journal->j_commit_sequence));
 690                read_lock(&journal->j_state_lock);
 691        }
 692        read_unlock(&journal->j_state_lock);
 693
 694        if (unlikely(is_journal_aborted(journal))) {
 695                printk(KERN_EMERG "journal commit I/O error\n");
 696                err = -EIO;
 697        }
 698        return err;
 699}
 700
 701/*
 702 * Log buffer allocation routines:
 703 */
 704
 705int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
 706{
 707        unsigned long blocknr;
 708
 709        write_lock(&journal->j_state_lock);
 710        J_ASSERT(journal->j_free > 1);
 711
 712        blocknr = journal->j_head;
 713        journal->j_head++;
 714        journal->j_free--;
 715        if (journal->j_head == journal->j_last)
 716                journal->j_head = journal->j_first;
 717        write_unlock(&journal->j_state_lock);
 718        return jbd2_journal_bmap(journal, blocknr, retp);
 719}
 720
 721/*
 722 * Conversion of logical to physical block numbers for the journal
 723 *
 724 * On external journals the journal blocks are identity-mapped, so
 725 * this is a no-op.  If needed, we can use j_blk_offset - everything is
 726 * ready.
 727 */
 728int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
 729                 unsigned long long *retp)
 730{
 731        int err = 0;
 732        unsigned long long ret;
 733
 734        if (journal->j_inode) {
 735                ret = bmap(journal->j_inode, blocknr);
 736                if (ret)
 737                        *retp = ret;
 738                else {
 739                        printk(KERN_ALERT "%s: journal block not found "
 740                                        "at offset %lu on %s\n",
 741                               __func__, blocknr, journal->j_devname);
 742                        err = -EIO;
 743                        __journal_abort_soft(journal, err);
 744                }
 745        } else {
 746                *retp = blocknr; /* +journal->j_blk_offset */
 747        }
 748        return err;
 749}
 750
 751/*
 752 * We play buffer_head aliasing tricks to write data/metadata blocks to
 753 * the journal without copying their contents, but for journal
 754 * descriptor blocks we do need to generate bona fide buffers.
 755 *
 756 * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
 757 * the buffer's contents they really should run flush_dcache_page(bh->b_page).
 758 * But we don't bother doing that, so there will be coherency problems with
 759 * mmaps of blockdevs which hold live JBD-controlled filesystems.
 760 */
 761struct journal_head *jbd2_journal_get_descriptor_buffer(journal_t *journal)
 762{
 763        struct buffer_head *bh;
 764        unsigned long long blocknr;
 765        int err;
 766
 767        err = jbd2_journal_next_log_block(journal, &blocknr);
 768
 769        if (err)
 770                return NULL;
 771
 772        bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
 773        if (!bh)
 774                return NULL;
 775        lock_buffer(bh);
 776        memset(bh->b_data, 0, journal->j_blocksize);
 777        set_buffer_uptodate(bh);
 778        unlock_buffer(bh);
 779        BUFFER_TRACE(bh, "return this buffer");
 780        return jbd2_journal_add_journal_head(bh);
 781}
 782
 783/*
 784 * Return tid of the oldest transaction in the journal and block in the journal
 785 * where the transaction starts.
 786 *
 787 * If the journal is now empty, return which will be the next transaction ID
 788 * we will write and where will that transaction start.
 789 *
 790 * The return value is 0 if journal tail cannot be pushed any further, 1 if
 791 * it can.
 792 */
 793int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
 794                              unsigned long *block)
 795{
 796        transaction_t *transaction;
 797        int ret;
 798
 799        read_lock(&journal->j_state_lock);
 800        spin_lock(&journal->j_list_lock);
 801        transaction = journal->j_checkpoint_transactions;
 802        if (transaction) {
 803                *tid = transaction->t_tid;
 804                *block = transaction->t_log_start;
 805        } else if ((transaction = journal->j_committing_transaction) != NULL) {
 806                *tid = transaction->t_tid;
 807                *block = transaction->t_log_start;
 808        } else if ((transaction = journal->j_running_transaction) != NULL) {
 809                *tid = transaction->t_tid;
 810                *block = journal->j_head;
 811        } else {
 812                *tid = journal->j_transaction_sequence;
 813                *block = journal->j_head;
 814        }
 815        ret = tid_gt(*tid, journal->j_tail_sequence);
 816        spin_unlock(&journal->j_list_lock);
 817        read_unlock(&journal->j_state_lock);
 818
 819        return ret;
 820}
 821
 822/*
 823 * Update information in journal structure and in on disk journal superblock
 824 * about log tail. This function does not check whether information passed in
 825 * really pushes log tail further. It's responsibility of the caller to make
 826 * sure provided log tail information is valid (e.g. by holding
 827 * j_checkpoint_mutex all the time between computing log tail and calling this
 828 * function as is the case with jbd2_cleanup_journal_tail()).
 829 *
 830 * Requires j_checkpoint_mutex
 831 */
 832void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
 833{
 834        unsigned long freed;
 835
 836        BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
 837
 838        /*
 839         * We cannot afford for write to remain in drive's caches since as
 840         * soon as we update j_tail, next transaction can start reusing journal
 841         * space and if we lose sb update during power failure we'd replay
 842         * old transaction with possibly newly overwritten data.
 843         */
 844        jbd2_journal_update_sb_log_tail(journal, tid, block, WRITE_FUA);
 845        write_lock(&journal->j_state_lock);
 846        freed = block - journal->j_tail;
 847        if (block < journal->j_tail)
 848                freed += journal->j_last - journal->j_first;
 849
 850        trace_jbd2_update_log_tail(journal, tid, block, freed);
 851        jbd_debug(1,
 852                  "Cleaning journal tail from %d to %d (offset %lu), "
 853                  "freeing %lu\n",
 854                  journal->j_tail_sequence, tid, block, freed);
 855
 856        journal->j_free += freed;
 857        journal->j_tail_sequence = tid;
 858        journal->j_tail = block;
 859        write_unlock(&journal->j_state_lock);
 860}
 861
 862/*
 863 * This is a variaon of __jbd2_update_log_tail which checks for validity of
 864 * provided log tail and locks j_checkpoint_mutex. So it is safe against races
 865 * with other threads updating log tail.
 866 */
 867void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
 868{
 869        mutex_lock(&journal->j_checkpoint_mutex);
 870        if (tid_gt(tid, journal->j_tail_sequence))
 871                __jbd2_update_log_tail(journal, tid, block);
 872        mutex_unlock(&journal->j_checkpoint_mutex);
 873}
 874
 875struct jbd2_stats_proc_session {
 876        journal_t *journal;
 877        struct transaction_stats_s *stats;
 878        int start;
 879        int max;
 880};
 881
 882static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos)
 883{
 884        return *pos ? NULL : SEQ_START_TOKEN;
 885}
 886
 887static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos)
 888{
 889        return NULL;
 890}
 891
 892static int jbd2_seq_info_show(struct seq_file *seq, void *v)
 893{
 894        struct jbd2_stats_proc_session *s = seq->private;
 895
 896        if (v != SEQ_START_TOKEN)
 897                return 0;
 898        seq_printf(seq, "%lu transaction, each up to %u blocks\n",
 899                        s->stats->ts_tid,
 900                        s->journal->j_max_transaction_buffers);
 901        if (s->stats->ts_tid == 0)
 902                return 0;
 903        seq_printf(seq, "average: \n  %ums waiting for transaction\n",
 904            jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid));
 905        seq_printf(seq, "  %ums running transaction\n",
 906            jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid));
 907        seq_printf(seq, "  %ums transaction was being locked\n",
 908            jiffies_to_msecs(s->stats->run.rs_locked / s->stats->ts_tid));
 909        seq_printf(seq, "  %ums flushing data (in ordered mode)\n",
 910            jiffies_to_msecs(s->stats->run.rs_flushing / s->stats->ts_tid));
 911        seq_printf(seq, "  %ums logging transaction\n",
 912            jiffies_to_msecs(s->stats->run.rs_logging / s->stats->ts_tid));
 913        seq_printf(seq, "  %lluus average transaction commit time\n",
 914                   div_u64(s->journal->j_average_commit_time, 1000));
 915        seq_printf(seq, "  %lu handles per transaction\n",
 916            s->stats->run.rs_handle_count / s->stats->ts_tid);
 917        seq_printf(seq, "  %lu blocks per transaction\n",
 918            s->stats->run.rs_blocks / s->stats->ts_tid);
 919        seq_printf(seq, "  %lu logged blocks per transaction\n",
 920            s->stats->run.rs_blocks_logged / s->stats->ts_tid);
 921        return 0;
 922}
 923
 924static void jbd2_seq_info_stop(struct seq_file *seq, void *v)
 925{
 926}
 927
 928static const struct seq_operations jbd2_seq_info_ops = {
 929        .start  = jbd2_seq_info_start,
 930        .next   = jbd2_seq_info_next,
 931        .stop   = jbd2_seq_info_stop,
 932        .show   = jbd2_seq_info_show,
 933};
 934
 935static int jbd2_seq_info_open(struct inode *inode, struct file *file)
 936{
 937        journal_t *journal = PDE(inode)->data;
 938        struct jbd2_stats_proc_session *s;
 939        int rc, size;
 940
 941        s = kmalloc(sizeof(*s), GFP_KERNEL);
 942        if (s == NULL)
 943                return -ENOMEM;
 944        size = sizeof(struct transaction_stats_s);
 945        s->stats = kmalloc(size, GFP_KERNEL);
 946        if (s->stats == NULL) {
 947                kfree(s);
 948                return -ENOMEM;
 949        }
 950        spin_lock(&journal->j_history_lock);
 951        memcpy(s->stats, &journal->j_stats, size);
 952        s->journal = journal;
 953        spin_unlock(&journal->j_history_lock);
 954
 955        rc = seq_open(file, &jbd2_seq_info_ops);
 956        if (rc == 0) {
 957                struct seq_file *m = file->private_data;
 958                m->private = s;
 959        } else {
 960                kfree(s->stats);
 961                kfree(s);
 962        }
 963        return rc;
 964
 965}
 966
 967static int jbd2_seq_info_release(struct inode *inode, struct file *file)
 968{
 969        struct seq_file *seq = file->private_data;
 970        struct jbd2_stats_proc_session *s = seq->private;
 971        kfree(s->stats);
 972        kfree(s);
 973        return seq_release(inode, file);
 974}
 975
 976static const struct file_operations jbd2_seq_info_fops = {
 977        .owner          = THIS_MODULE,
 978        .open           = jbd2_seq_info_open,
 979        .read           = seq_read,
 980        .llseek         = seq_lseek,
 981        .release        = jbd2_seq_info_release,
 982};
 983
 984static struct proc_dir_entry *proc_jbd2_stats;
 985
 986static void jbd2_stats_proc_init(journal_t *journal)
 987{
 988        journal->j_proc_entry = proc_mkdir(journal->j_devname, proc_jbd2_stats);
 989        if (journal->j_proc_entry) {
 990                proc_create_data("info", S_IRUGO, journal->j_proc_entry,
 991                                 &jbd2_seq_info_fops, journal);
 992        }
 993}
 994
 995static void jbd2_stats_proc_exit(journal_t *journal)
 996{
 997        remove_proc_entry("info", journal->j_proc_entry);
 998        remove_proc_entry(journal->j_devname, proc_jbd2_stats);
 999}
1000
1001/*
1002 * Management for journal control blocks: functions to create and
1003 * destroy journal_t structures, and to initialise and read existing
1004 * journal blocks from disk.  */
1005
1006/* First: create and setup a journal_t object in memory.  We initialise
1007 * very few fields yet: that has to wait until we have created the
1008 * journal structures from from scratch, or loaded them from disk. */
1009
1010static journal_t * journal_init_common (void)
1011{
1012        journal_t *journal;
1013        int err;
1014
1015        journal = kzalloc(sizeof(*journal), GFP_KERNEL);
1016        if (!journal)
1017                return NULL;
1018
1019        init_waitqueue_head(&journal->j_wait_transaction_locked);
1020        init_waitqueue_head(&journal->j_wait_logspace);
1021        init_waitqueue_head(&journal->j_wait_done_commit);
1022        init_waitqueue_head(&journal->j_wait_checkpoint);
1023        init_waitqueue_head(&journal->j_wait_commit);
1024        init_waitqueue_head(&journal->j_wait_updates);
1025        mutex_init(&journal->j_barrier);
1026        mutex_init(&journal->j_checkpoint_mutex);
1027        spin_lock_init(&journal->j_revoke_lock);
1028        spin_lock_init(&journal->j_list_lock);
1029        rwlock_init(&journal->j_state_lock);
1030
1031        journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE);
1032        journal->j_min_batch_time = 0;
1033        journal->j_max_batch_time = 15000; /* 15ms */
1034
1035        /* The journal is marked for error until we succeed with recovery! */
1036        journal->j_flags = JBD2_ABORT;
1037
1038        /* Set up a default-sized revoke table for the new mount. */
1039        err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
1040        if (err) {
1041                kfree(journal);
1042                return NULL;
1043        }
1044
1045        spin_lock_init(&journal->j_history_lock);
1046
1047        return journal;
1048}
1049
1050/* jbd2_journal_init_dev and jbd2_journal_init_inode:
1051 *
1052 * Create a journal structure assigned some fixed set of disk blocks to
1053 * the journal.  We don't actually touch those disk blocks yet, but we
1054 * need to set up all of the mapping information to tell the journaling
1055 * system where the journal blocks are.
1056 *
1057 */
1058
1059/**
1060 *  journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
1061 *  @bdev: Block device on which to create the journal
1062 *  @fs_dev: Device which hold journalled filesystem for this journal.
1063 *  @start: Block nr Start of journal.
1064 *  @len:  Length of the journal in blocks.
1065 *  @blocksize: blocksize of journalling device
1066 *
1067 *  Returns: a newly created journal_t *
1068 *
1069 *  jbd2_journal_init_dev creates a journal which maps a fixed contiguous
1070 *  range of blocks on an arbitrary block device.
1071 *
1072 */
1073journal_t * jbd2_journal_init_dev(struct block_device *bdev,
1074                        struct block_device *fs_dev,
1075                        unsigned long long start, int len, int blocksize)
1076{
1077        journal_t *journal = journal_init_common();
1078        struct buffer_head *bh;
1079        char *p;
1080        int n;
1081
1082        if (!journal)
1083                return NULL;
1084
1085        /* journal descriptor can store up to n blocks -bzzz */
1086        journal->j_blocksize = blocksize;
1087        journal->j_dev = bdev;
1088        journal->j_fs_dev = fs_dev;
1089        journal->j_blk_offset = start;
1090        journal->j_maxlen = len;
1091        bdevname(journal->j_dev, journal->j_devname);
1092        p = journal->j_devname;
1093        while ((p = strchr(p, '/')))
1094                *p = '!';
1095        jbd2_stats_proc_init(journal);
1096        n = journal->j_blocksize / sizeof(journal_block_tag_t);
1097        journal->j_wbufsize = n;
1098        journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
1099        if (!journal->j_wbuf) {
1100                printk(KERN_ERR "%s: Can't allocate bhs for commit thread\n",
1101                        __func__);
1102                goto out_err;
1103        }
1104
1105        bh = __getblk(journal->j_dev, start, journal->j_blocksize);
1106        if (!bh) {
1107                printk(KERN_ERR
1108                       "%s: Cannot get buffer for journal superblock\n",
1109                       __func__);
1110                goto out_err;
1111        }
1112        journal->j_sb_buffer = bh;
1113        journal->j_superblock = (journal_superblock_t *)bh->b_data;
1114
1115        return journal;
1116out_err:
1117        kfree(journal->j_wbuf);
1118        jbd2_stats_proc_exit(journal);
1119        kfree(journal);
1120        return NULL;
1121}
1122
1123/**
1124 *  journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
1125 *  @inode: An inode to create the journal in
1126 *
1127 * jbd2_journal_init_inode creates a journal which maps an on-disk inode as
1128 * the journal.  The inode must exist already, must support bmap() and
1129 * must have all data blocks preallocated.
1130 */
1131journal_t * jbd2_journal_init_inode (struct inode *inode)
1132{
1133        struct buffer_head *bh;
1134        journal_t *journal = journal_init_common();
1135        char *p;
1136        int err;
1137        int n;
1138        unsigned long long blocknr;
1139
1140        if (!journal)
1141                return NULL;
1142
1143        journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev;
1144        journal->j_inode = inode;
1145        bdevname(journal->j_dev, journal->j_devname);
1146        p = journal->j_devname;
1147        while ((p = strchr(p, '/')))
1148                *p = '!';
1149        p = journal->j_devname + strlen(journal->j_devname);
1150        sprintf(p, "-%lu", journal->j_inode->i_ino);
1151        jbd_debug(1,
1152                  "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
1153                  journal, inode->i_sb->s_id, inode->i_ino,
1154                  (long long) inode->i_size,
1155                  inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
1156
1157        journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits;
1158        journal->j_blocksize = inode->i_sb->s_blocksize;
1159        jbd2_stats_proc_init(journal);
1160
1161        /* journal descriptor can store up to n blocks -bzzz */
1162        n = journal->j_blocksize / sizeof(journal_block_tag_t);
1163        journal->j_wbufsize = n;
1164        journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
1165        if (!journal->j_wbuf) {
1166                printk(KERN_ERR "%s: Can't allocate bhs for commit thread\n",
1167                        __func__);
1168                goto out_err;
1169        }
1170
1171        err = jbd2_journal_bmap(journal, 0, &blocknr);
1172        /* If that failed, give up */
1173        if (err) {
1174                printk(KERN_ERR "%s: Cannot locate journal superblock\n",
1175                       __func__);
1176                goto out_err;
1177        }
1178
1179        bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
1180        if (!bh) {
1181                printk(KERN_ERR
1182                       "%s: Cannot get buffer for journal superblock\n",
1183                       __func__);
1184                goto out_err;
1185        }
1186        journal->j_sb_buffer = bh;
1187        journal->j_superblock = (journal_superblock_t *)bh->b_data;
1188
1189        return journal;
1190out_err:
1191        kfree(journal->j_wbuf);
1192        jbd2_stats_proc_exit(journal);
1193        kfree(journal);
1194        return NULL;
1195}
1196
1197/*
1198 * If the journal init or create aborts, we need to mark the journal
1199 * superblock as being NULL to prevent the journal destroy from writing
1200 * back a bogus superblock.
1201 */
1202static void journal_fail_superblock (journal_t *journal)
1203{
1204        struct buffer_head *bh = journal->j_sb_buffer;
1205        brelse(bh);
1206        journal->j_sb_buffer = NULL;
1207}
1208
1209/*
1210 * Given a journal_t structure, initialise the various fields for
1211 * startup of a new journaling session.  We use this both when creating
1212 * a journal, and after recovering an old journal to reset it for
1213 * subsequent use.
1214 */
1215
1216static int journal_reset(journal_t *journal)
1217{
1218        journal_superblock_t *sb = journal->j_superblock;
1219        unsigned long long first, last;
1220
1221        first = be32_to_cpu(sb->s_first);
1222        last = be32_to_cpu(sb->s_maxlen);
1223        if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) {
1224                printk(KERN_ERR "JBD2: Journal too short (blocks %llu-%llu).\n",
1225                       first, last);
1226                journal_fail_superblock(journal);
1227                return -EINVAL;
1228        }
1229
1230        journal->j_first = first;
1231        journal->j_last = last;
1232
1233        journal->j_head = first;
1234        journal->j_tail = first;
1235        journal->j_free = last - first;
1236
1237        journal->j_tail_sequence = journal->j_transaction_sequence;
1238        journal->j_commit_sequence = journal->j_transaction_sequence - 1;
1239        journal->j_commit_request = journal->j_commit_sequence;
1240
1241        journal->j_max_transaction_buffers = journal->j_maxlen / 4;
1242
1243        /*
1244         * As a special case, if the on-disk copy is already marked as needing
1245         * no recovery (s_start == 0), then we can safely defer the superblock
1246         * update until the next commit by setting JBD2_FLUSHED.  This avoids
1247         * attempting a write to a potential-readonly device.
1248         */
1249        if (sb->s_start == 0) {
1250                jbd_debug(1, "JBD2: Skipping superblock update on recovered sb "
1251                        "(start %ld, seq %d, errno %d)\n",
1252                        journal->j_tail, journal->j_tail_sequence,
1253                        journal->j_errno);
1254                journal->j_flags |= JBD2_FLUSHED;
1255        } else {
1256                /* Lock here to make assertions happy... */
1257                mutex_lock(&journal->j_checkpoint_mutex);
1258                /*
1259                 * Update log tail information. We use WRITE_FUA since new
1260                 * transaction will start reusing journal space and so we
1261                 * must make sure information about current log tail is on
1262                 * disk before that.
1263                 */
1264                jbd2_journal_update_sb_log_tail(journal,
1265                                                journal->j_tail_sequence,
1266                                                journal->j_tail,
1267                                                WRITE_FUA);
1268                mutex_unlock(&journal->j_checkpoint_mutex);
1269        }
1270        return jbd2_journal_start_thread(journal);
1271}
1272
1273static void jbd2_write_superblock(journal_t *journal, int write_op)
1274{
1275        struct buffer_head *bh = journal->j_sb_buffer;
1276        int ret;
1277
1278        trace_jbd2_write_superblock(journal, write_op);
1279        if (!(journal->j_flags & JBD2_BARRIER))
1280                write_op &= ~(REQ_FUA | REQ_FLUSH);
1281        lock_buffer(bh);
1282        if (buffer_write_io_error(bh)) {
1283                /*
1284                 * Oh, dear.  A previous attempt to write the journal
1285                 * superblock failed.  This could happen because the
1286                 * USB device was yanked out.  Or it could happen to
1287                 * be a transient write error and maybe the block will
1288                 * be remapped.  Nothing we can do but to retry the
1289                 * write and hope for the best.
1290                 */
1291                printk(KERN_ERR "JBD2: previous I/O error detected "
1292                       "for journal superblock update for %s.\n",
1293                       journal->j_devname);
1294                clear_buffer_write_io_error(bh);
1295                set_buffer_uptodate(bh);
1296        }
1297        get_bh(bh);
1298        bh->b_end_io = end_buffer_write_sync;
1299        ret = submit_bh(write_op, bh);
1300        wait_on_buffer(bh);
1301        if (buffer_write_io_error(bh)) {
1302                clear_buffer_write_io_error(bh);
1303                set_buffer_uptodate(bh);
1304                ret = -EIO;
1305        }
1306        if (ret) {
1307                printk(KERN_ERR "JBD2: Error %d detected when updating "
1308                       "journal superblock for %s.\n", ret,
1309                       journal->j_devname);
1310        }
1311}
1312
1313/**
1314 * jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk.
1315 * @journal: The journal to update.
1316 * @tail_tid: TID of the new transaction at the tail of the log
1317 * @tail_block: The first block of the transaction at the tail of the log
1318 * @write_op: With which operation should we write the journal sb
1319 *
1320 * Update a journal's superblock information about log tail and write it to
1321 * disk, waiting for the IO to complete.
1322 */
1323void jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
1324                                     unsigned long tail_block, int write_op)
1325{
1326        journal_superblock_t *sb = journal->j_superblock;
1327
1328        BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1329        jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
1330                  tail_block, tail_tid);
1331
1332        sb->s_sequence = cpu_to_be32(tail_tid);
1333        sb->s_start    = cpu_to_be32(tail_block);
1334
1335        jbd2_write_superblock(journal, write_op);
1336
1337        /* Log is no longer empty */
1338        write_lock(&journal->j_state_lock);
1339        WARN_ON(!sb->s_sequence);
1340        journal->j_flags &= ~JBD2_FLUSHED;
1341        write_unlock(&journal->j_state_lock);
1342}
1343
1344/**
1345 * jbd2_mark_journal_empty() - Mark on disk journal as empty.
1346 * @journal: The journal to update.
1347 *
1348 * Update a journal's dynamic superblock fields to show that journal is empty.
1349 * Write updated superblock to disk waiting for IO to complete.
1350 */
1351static void jbd2_mark_journal_empty(journal_t *journal)
1352{
1353        journal_superblock_t *sb = journal->j_superblock;
1354
1355        BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1356        read_lock(&journal->j_state_lock);
1357        /* Is it already empty? */
1358        if (sb->s_start == 0) {
1359                read_unlock(&journal->j_state_lock);
1360                return;
1361        }
1362        jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n",
1363                  journal->j_tail_sequence);
1364
1365        sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
1366        sb->s_start    = cpu_to_be32(0);
1367        read_unlock(&journal->j_state_lock);
1368
1369        jbd2_write_superblock(journal, WRITE_FUA);
1370
1371        /* Log is no longer empty */
1372        write_lock(&journal->j_state_lock);
1373        journal->j_flags |= JBD2_FLUSHED;
1374        write_unlock(&journal->j_state_lock);
1375}
1376
1377
1378/**
1379 * jbd2_journal_update_sb_errno() - Update error in the journal.
1380 * @journal: The journal to update.
1381 *
1382 * Update a journal's errno.  Write updated superblock to disk waiting for IO
1383 * to complete.
1384 */
1385void jbd2_journal_update_sb_errno(journal_t *journal)
1386{
1387        journal_superblock_t *sb = journal->j_superblock;
1388
1389        read_lock(&journal->j_state_lock);
1390        jbd_debug(1, "JBD2: updating superblock error (errno %d)\n",
1391                  journal->j_errno);
1392        sb->s_errno    = cpu_to_be32(journal->j_errno);
1393        jbd2_superblock_csum_set(journal, sb);
1394        read_unlock(&journal->j_state_lock);
1395
1396        jbd2_write_superblock(journal, WRITE_SYNC);
1397}
1398EXPORT_SYMBOL(jbd2_journal_update_sb_errno);
1399
1400/*
1401 * Read the superblock for a given journal, performing initial
1402 * validation of the format.
1403 */
1404static int journal_get_superblock(journal_t *journal)
1405{
1406        struct buffer_head *bh;
1407        journal_superblock_t *sb;
1408        int err = -EIO;
1409
1410        bh = journal->j_sb_buffer;
1411
1412        J_ASSERT(bh != NULL);
1413        if (!buffer_uptodate(bh)) {
1414                ll_rw_block(READ, 1, &bh);
1415                wait_on_buffer(bh);
1416                if (!buffer_uptodate(bh)) {
1417                        printk(KERN_ERR
1418                                "JBD2: IO error reading journal superblock\n");
1419                        goto out;
1420                }
1421        }
1422
1423        if (buffer_verified(bh))
1424                return 0;
1425
1426        sb = journal->j_superblock;
1427
1428        err = -EINVAL;
1429
1430        if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
1431            sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1432                printk(KERN_WARNING "JBD2: no valid journal superblock found\n");
1433                goto out;
1434        }
1435
1436        switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1437        case JBD2_SUPERBLOCK_V1:
1438                journal->j_format_version = 1;
1439                break;
1440        case JBD2_SUPERBLOCK_V2:
1441                journal->j_format_version = 2;
1442                break;
1443        default:
1444                printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n");
1445                goto out;
1446        }
1447
1448        if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
1449                journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
1450        else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
1451                printk(KERN_WARNING "JBD2: journal file too short\n");
1452                goto out;
1453        }
1454
1455        if (be32_to_cpu(sb->s_first) == 0 ||
1456            be32_to_cpu(sb->s_first) >= journal->j_maxlen) {
1457                printk(KERN_WARNING
1458                        "JBD2: Invalid start block of journal: %u\n",
1459                        be32_to_cpu(sb->s_first));
1460                goto out;
1461        }
1462
1463        if (JBD2_HAS_COMPAT_FEATURE(journal, JBD2_FEATURE_COMPAT_CHECKSUM) &&
1464            JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2)) {
1465                /* Can't have checksum v1 and v2 on at the same time! */
1466                printk(KERN_ERR "JBD: Can't enable checksumming v1 and v2 "
1467                       "at the same time!\n");
1468                goto out;
1469        }
1470
1471        if (!jbd2_verify_csum_type(journal, sb)) {
1472                printk(KERN_ERR "JBD: Unknown checksum type\n");
1473                goto out;
1474        }
1475
1476        /* Load the checksum driver */
1477        if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2)) {
1478                journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
1479                if (IS_ERR(journal->j_chksum_driver)) {
1480                        printk(KERN_ERR "JBD: Cannot load crc32c driver.\n");
1481                        err = PTR_ERR(journal->j_chksum_driver);
1482                        journal->j_chksum_driver = NULL;
1483                        goto out;
1484                }
1485        }
1486
1487        /* Check superblock checksum */
1488        if (!jbd2_superblock_csum_verify(journal, sb)) {
1489                printk(KERN_ERR "JBD: journal checksum error\n");
1490                goto out;
1491        }
1492
1493        /* Precompute checksum seed for all metadata */
1494        if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
1495                journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
1496                                                   sizeof(sb->s_uuid));
1497
1498        set_buffer_verified(bh);
1499
1500        return 0;
1501
1502out:
1503        journal_fail_superblock(journal);
1504        return err;
1505}
1506
1507/*
1508 * Load the on-disk journal superblock and read the key fields into the
1509 * journal_t.
1510 */
1511
1512static int load_superblock(journal_t *journal)
1513{
1514        int err;
1515        journal_superblock_t *sb;
1516
1517        err = journal_get_superblock(journal);
1518        if (err)
1519                return err;
1520
1521        sb = journal->j_superblock;
1522
1523        journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
1524        journal->j_tail = be32_to_cpu(sb->s_start);
1525        journal->j_first = be32_to_cpu(sb->s_first);
1526        journal->j_last = be32_to_cpu(sb->s_maxlen);
1527        journal->j_errno = be32_to_cpu(sb->s_errno);
1528
1529        return 0;
1530}
1531
1532
1533/**
1534 * int jbd2_journal_load() - Read journal from disk.
1535 * @journal: Journal to act on.
1536 *
1537 * Given a journal_t structure which tells us which disk blocks contain
1538 * a journal, read the journal from disk to initialise the in-memory
1539 * structures.
1540 */
1541int jbd2_journal_load(journal_t *journal)
1542{
1543        int err;
1544        journal_superblock_t *sb;
1545
1546        err = load_superblock(journal);
1547        if (err)
1548                return err;
1549
1550        sb = journal->j_superblock;
1551        /* If this is a V2 superblock, then we have to check the
1552         * features flags on it. */
1553
1554        if (journal->j_format_version >= 2) {
1555                if ((sb->s_feature_ro_compat &
1556                     ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) ||
1557                    (sb->s_feature_incompat &
1558                     ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) {
1559                        printk(KERN_WARNING
1560                                "JBD2: Unrecognised features on journal\n");
1561                        return -EINVAL;
1562                }
1563        }
1564
1565        /*
1566         * Create a slab for this blocksize
1567         */
1568        err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize));
1569        if (err)
1570                return err;
1571
1572        /* Let the recovery code check whether it needs to recover any
1573         * data from the journal. */
1574        if (jbd2_journal_recover(journal))
1575                goto recovery_error;
1576
1577        if (journal->j_failed_commit) {
1578                printk(KERN_ERR "JBD2: journal transaction %u on %s "
1579                       "is corrupt.\n", journal->j_failed_commit,
1580                       journal->j_devname);
1581                return -EIO;
1582        }
1583
1584        /* OK, we've finished with the dynamic journal bits:
1585         * reinitialise the dynamic contents of the superblock in memory
1586         * and reset them on disk. */
1587        if (journal_reset(journal))
1588                goto recovery_error;
1589
1590        journal->j_flags &= ~JBD2_ABORT;
1591        journal->j_flags |= JBD2_LOADED;
1592        return 0;
1593
1594recovery_error:
1595        printk(KERN_WARNING "JBD2: recovery failed\n");
1596        return -EIO;
1597}
1598
1599/**
1600 * void jbd2_journal_destroy() - Release a journal_t structure.
1601 * @journal: Journal to act on.
1602 *
1603 * Release a journal_t structure once it is no longer in use by the
1604 * journaled object.
1605 * Return <0 if we couldn't clean up the journal.
1606 */
1607int jbd2_journal_destroy(journal_t *journal)
1608{
1609        int err = 0;
1610
1611        /* Wait for the commit thread to wake up and die. */
1612        journal_kill_thread(journal);
1613
1614        /* Force a final log commit */
1615        if (journal->j_running_transaction)
1616                jbd2_journal_commit_transaction(journal);
1617
1618        /* Force any old transactions to disk */
1619
1620        /* Totally anal locking here... */
1621        spin_lock(&journal->j_list_lock);
1622        while (journal->j_checkpoint_transactions != NULL) {
1623                spin_unlock(&journal->j_list_lock);
1624                mutex_lock(&journal->j_checkpoint_mutex);
1625                jbd2_log_do_checkpoint(journal);
1626                mutex_unlock(&journal->j_checkpoint_mutex);
1627                spin_lock(&journal->j_list_lock);
1628        }
1629
1630        J_ASSERT(journal->j_running_transaction == NULL);
1631        J_ASSERT(journal->j_committing_transaction == NULL);
1632        J_ASSERT(journal->j_checkpoint_transactions == NULL);
1633        spin_unlock(&journal->j_list_lock);
1634
1635        if (journal->j_sb_buffer) {
1636                if (!is_journal_aborted(journal)) {
1637                        mutex_lock(&journal->j_checkpoint_mutex);
1638                        jbd2_mark_journal_empty(journal);
1639                        mutex_unlock(&journal->j_checkpoint_mutex);
1640                } else
1641                        err = -EIO;
1642                brelse(journal->j_sb_buffer);
1643        }
1644
1645        if (journal->j_proc_entry)
1646                jbd2_stats_proc_exit(journal);
1647        if (journal->j_inode)
1648                iput(journal->j_inode);
1649        if (journal->j_revoke)
1650                jbd2_journal_destroy_revoke(journal);
1651        if (journal->j_chksum_driver)
1652                crypto_free_shash(journal->j_chksum_driver);
1653        kfree(journal->j_wbuf);
1654        kfree(journal);
1655
1656        return err;
1657}
1658
1659
1660/**
1661 *int jbd2_journal_check_used_features () - Check if features specified are used.
1662 * @journal: Journal to check.
1663 * @compat: bitmask of compatible features
1664 * @ro: bitmask of features that force read-only mount
1665 * @incompat: bitmask of incompatible features
1666 *
1667 * Check whether the journal uses all of a given set of
1668 * features.  Return true (non-zero) if it does.
1669 **/
1670
1671int jbd2_journal_check_used_features (journal_t *journal, unsigned long compat,
1672                                 unsigned long ro, unsigned long incompat)
1673{
1674        journal_superblock_t *sb;
1675
1676        if (!compat && !ro && !incompat)
1677                return 1;
1678        /* Load journal superblock if it is not loaded yet. */
1679        if (journal->j_format_version == 0 &&
1680            journal_get_superblock(journal) != 0)
1681                return 0;
1682        if (journal->j_format_version == 1)
1683                return 0;
1684
1685        sb = journal->j_superblock;
1686
1687        if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
1688            ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
1689            ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
1690                return 1;
1691
1692        return 0;
1693}
1694
1695/**
1696 * int jbd2_journal_check_available_features() - Check feature set in journalling layer
1697 * @journal: Journal to check.
1698 * @compat: bitmask of compatible features
1699 * @ro: bitmask of features that force read-only mount
1700 * @incompat: bitmask of incompatible features
1701 *
1702 * Check whether the journaling code supports the use of
1703 * all of a given set of features on this journal.  Return true
1704 * (non-zero) if it can. */
1705
1706int jbd2_journal_check_available_features (journal_t *journal, unsigned long compat,
1707                                      unsigned long ro, unsigned long incompat)
1708{
1709        if (!compat && !ro && !incompat)
1710                return 1;
1711
1712        /* We can support any known requested features iff the
1713         * superblock is in version 2.  Otherwise we fail to support any
1714         * extended sb features. */
1715
1716        if (journal->j_format_version != 2)
1717                return 0;
1718
1719        if ((compat   & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
1720            (ro       & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro &&
1721            (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat)
1722                return 1;
1723
1724        return 0;
1725}
1726
1727/**
1728 * int jbd2_journal_set_features () - Mark a given journal feature in the superblock
1729 * @journal: Journal to act on.
1730 * @compat: bitmask of compatible features
1731 * @ro: bitmask of features that force read-only mount
1732 * @incompat: bitmask of incompatible features
1733 *
1734 * Mark a given journal feature as present on the
1735 * superblock.  Returns true if the requested features could be set.
1736 *
1737 */
1738
1739int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
1740                          unsigned long ro, unsigned long incompat)
1741{
1742#define INCOMPAT_FEATURE_ON(f) \
1743                ((incompat & (f)) && !(sb->s_feature_incompat & cpu_to_be32(f)))
1744#define COMPAT_FEATURE_ON(f) \
1745                ((compat & (f)) && !(sb->s_feature_compat & cpu_to_be32(f)))
1746        journal_superblock_t *sb;
1747
1748        if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
1749                return 1;
1750
1751        if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
1752                return 0;
1753
1754        /* Asking for checksumming v2 and v1?  Only give them v2. */
1755        if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V2 &&
1756            compat & JBD2_FEATURE_COMPAT_CHECKSUM)
1757                compat &= ~JBD2_FEATURE_COMPAT_CHECKSUM;
1758
1759        jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
1760                  compat, ro, incompat);
1761
1762        sb = journal->j_superblock;
1763
1764        /* If enabling v2 checksums, update superblock */
1765        if (INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V2)) {
1766                sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
1767                sb->s_feature_compat &=
1768                        ~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
1769
1770                /* Load the checksum driver */
1771                if (journal->j_chksum_driver == NULL) {
1772                        journal->j_chksum_driver = crypto_alloc_shash("crc32c",
1773                                                                      0, 0);
1774                        if (IS_ERR(journal->j_chksum_driver)) {
1775                                printk(KERN_ERR "JBD: Cannot load crc32c "
1776                                       "driver.\n");
1777                                journal->j_chksum_driver = NULL;
1778                                return 0;
1779                        }
1780                }
1781
1782                /* Precompute checksum seed for all metadata */
1783                if (JBD2_HAS_INCOMPAT_FEATURE(journal,
1784                                              JBD2_FEATURE_INCOMPAT_CSUM_V2))
1785                        journal->j_csum_seed = jbd2_chksum(journal, ~0,
1786                                                           sb->s_uuid,
1787                                                           sizeof(sb->s_uuid));
1788        }
1789
1790        /* If enabling v1 checksums, downgrade superblock */
1791        if (COMPAT_FEATURE_ON(JBD2_FEATURE_COMPAT_CHECKSUM))
1792                sb->s_feature_incompat &=
1793                        ~cpu_to_be32(JBD2_FEATURE_INCOMPAT_CSUM_V2);
1794
1795        sb->s_feature_compat    |= cpu_to_be32(compat);
1796        sb->s_feature_ro_compat |= cpu_to_be32(ro);
1797        sb->s_feature_incompat  |= cpu_to_be32(incompat);
1798
1799        return 1;
1800#undef COMPAT_FEATURE_ON
1801#undef INCOMPAT_FEATURE_ON
1802}
1803
1804/*
1805 * jbd2_journal_clear_features () - Clear a given journal feature in the
1806 *                                  superblock
1807 * @journal: Journal to act on.
1808 * @compat: bitmask of compatible features
1809 * @ro: bitmask of features that force read-only mount
1810 * @incompat: bitmask of incompatible features
1811 *
1812 * Clear a given journal feature as present on the
1813 * superblock.
1814 */
1815void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
1816                                unsigned long ro, unsigned long incompat)
1817{
1818        journal_superblock_t *sb;
1819
1820        jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
1821                  compat, ro, incompat);
1822
1823        sb = journal->j_superblock;
1824
1825        sb->s_feature_compat    &= ~cpu_to_be32(compat);
1826        sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
1827        sb->s_feature_incompat  &= ~cpu_to_be32(incompat);
1828}
1829EXPORT_SYMBOL(jbd2_journal_clear_features);
1830
1831/**
1832 * int jbd2_journal_flush () - Flush journal
1833 * @journal: Journal to act on.
1834 *
1835 * Flush all data for a given journal to disk and empty the journal.
1836 * Filesystems can use this when remounting readonly to ensure that
1837 * recovery does not need to happen on remount.
1838 */
1839
1840int jbd2_journal_flush(journal_t *journal)
1841{
1842        int err = 0;
1843        transaction_t *transaction = NULL;
1844
1845        write_lock(&journal->j_state_lock);
1846
1847        /* Force everything buffered to the log... */
1848        if (journal->j_running_transaction) {
1849                transaction = journal->j_running_transaction;
1850                __jbd2_log_start_commit(journal, transaction->t_tid);
1851        } else if (journal->j_committing_transaction)
1852                transaction = journal->j_committing_transaction;
1853
1854        /* Wait for the log commit to complete... */
1855        if (transaction) {
1856                tid_t tid = transaction->t_tid;
1857
1858                write_unlock(&journal->j_state_lock);
1859                jbd2_log_wait_commit(journal, tid);
1860        } else {
1861                write_unlock(&journal->j_state_lock);
1862        }
1863
1864        /* ...and flush everything in the log out to disk. */
1865        spin_lock(&journal->j_list_lock);
1866        while (!err && journal->j_checkpoint_transactions != NULL) {
1867                spin_unlock(&journal->j_list_lock);
1868                mutex_lock(&journal->j_checkpoint_mutex);
1869                err = jbd2_log_do_checkpoint(journal);
1870                mutex_unlock(&journal->j_checkpoint_mutex);
1871                spin_lock(&journal->j_list_lock);
1872        }
1873        spin_unlock(&journal->j_list_lock);
1874
1875        if (is_journal_aborted(journal))
1876                return -EIO;
1877
1878        mutex_lock(&journal->j_checkpoint_mutex);
1879        jbd2_cleanup_journal_tail(journal);
1880
1881        /* Finally, mark the journal as really needing no recovery.
1882         * This sets s_start==0 in the underlying superblock, which is
1883         * the magic code for a fully-recovered superblock.  Any future
1884         * commits of data to the journal will restore the current
1885         * s_start value. */
1886        jbd2_mark_journal_empty(journal);
1887        mutex_unlock(&journal->j_checkpoint_mutex);
1888        write_lock(&journal->j_state_lock);
1889        J_ASSERT(!journal->j_running_transaction);
1890        J_ASSERT(!journal->j_committing_transaction);
1891        J_ASSERT(!journal->j_checkpoint_transactions);
1892        J_ASSERT(journal->j_head == journal->j_tail);
1893        J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
1894        write_unlock(&journal->j_state_lock);
1895        return 0;
1896}
1897
1898/**
1899 * int jbd2_journal_wipe() - Wipe journal contents
1900 * @journal: Journal to act on.
1901 * @write: flag (see below)
1902 *
1903 * Wipe out all of the contents of a journal, safely.  This will produce
1904 * a warning if the journal contains any valid recovery information.
1905 * Must be called between journal_init_*() and jbd2_journal_load().
1906 *
1907 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
1908 * we merely suppress recovery.
1909 */
1910
1911int jbd2_journal_wipe(journal_t *journal, int write)
1912{
1913        int err = 0;
1914
1915        J_ASSERT (!(journal->j_flags & JBD2_LOADED));
1916
1917        err = load_superblock(journal);
1918        if (err)
1919                return err;
1920
1921        if (!journal->j_tail)
1922                goto no_recovery;
1923
1924        printk(KERN_WARNING "JBD2: %s recovery information on journal\n",
1925                write ? "Clearing" : "Ignoring");
1926
1927        err = jbd2_journal_skip_recovery(journal);
1928        if (write) {
1929                /* Lock to make assertions happy... */
1930                mutex_lock(&journal->j_checkpoint_mutex);
1931                jbd2_mark_journal_empty(journal);
1932                mutex_unlock(&journal->j_checkpoint_mutex);
1933        }
1934
1935 no_recovery:
1936        return err;
1937}
1938
1939/*
1940 * Journal abort has very specific semantics, which we describe
1941 * for journal abort.
1942 *
1943 * Two internal functions, which provide abort to the jbd layer
1944 * itself are here.
1945 */
1946
1947/*
1948 * Quick version for internal journal use (doesn't lock the journal).
1949 * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
1950 * and don't attempt to make any other journal updates.
1951 */
1952void __jbd2_journal_abort_hard(journal_t *journal)
1953{
1954        transaction_t *transaction;
1955
1956        if (journal->j_flags & JBD2_ABORT)
1957                return;
1958
1959        printk(KERN_ERR "Aborting journal on device %s.\n",
1960               journal->j_devname);
1961
1962        write_lock(&journal->j_state_lock);
1963        journal->j_flags |= JBD2_ABORT;
1964        transaction = journal->j_running_transaction;
1965        if (transaction)
1966                __jbd2_log_start_commit(journal, transaction->t_tid);
1967        write_unlock(&journal->j_state_lock);
1968}
1969
1970/* Soft abort: record the abort error status in the journal superblock,
1971 * but don't do any other IO. */
1972static void __journal_abort_soft (journal_t *journal, int errno)
1973{
1974        if (journal->j_flags & JBD2_ABORT)
1975                return;
1976
1977        if (!journal->j_errno)
1978                journal->j_errno = errno;
1979
1980        __jbd2_journal_abort_hard(journal);
1981
1982        if (errno)
1983                jbd2_journal_update_sb_errno(journal);
1984}
1985
1986/**
1987 * void jbd2_journal_abort () - Shutdown the journal immediately.
1988 * @journal: the journal to shutdown.
1989 * @errno:   an error number to record in the journal indicating
1990 *           the reason for the shutdown.
1991 *
1992 * Perform a complete, immediate shutdown of the ENTIRE
1993 * journal (not of a single transaction).  This operation cannot be
1994 * undone without closing and reopening the journal.
1995 *
1996 * The jbd2_journal_abort function is intended to support higher level error
1997 * recovery mechanisms such as the ext2/ext3 remount-readonly error
1998 * mode.
1999 *
2000 * Journal abort has very specific semantics.  Any existing dirty,
2001 * unjournaled buffers in the main filesystem will still be written to
2002 * disk by bdflush, but the journaling mechanism will be suspended
2003 * immediately and no further transaction commits will be honoured.
2004 *
2005 * Any dirty, journaled buffers will be written back to disk without
2006 * hitting the journal.  Atomicity cannot be guaranteed on an aborted
2007 * filesystem, but we _do_ attempt to leave as much data as possible
2008 * behind for fsck to use for cleanup.
2009 *
2010 * Any attempt to get a new transaction handle on a journal which is in
2011 * ABORT state will just result in an -EROFS error return.  A
2012 * jbd2_journal_stop on an existing handle will return -EIO if we have
2013 * entered abort state during the update.
2014 *
2015 * Recursive transactions are not disturbed by journal abort until the
2016 * final jbd2_journal_stop, which will receive the -EIO error.
2017 *
2018 * Finally, the jbd2_journal_abort call allows the caller to supply an errno
2019 * which will be recorded (if possible) in the journal superblock.  This
2020 * allows a client to record failure conditions in the middle of a
2021 * transaction without having to complete the transaction to record the
2022 * failure to disk.  ext3_error, for example, now uses this
2023 * functionality.
2024 *
2025 * Errors which originate from within the journaling layer will NOT
2026 * supply an errno; a null errno implies that absolutely no further
2027 * writes are done to the journal (unless there are any already in
2028 * progress).
2029 *
2030 */
2031
2032void jbd2_journal_abort(journal_t *journal, int errno)
2033{
2034        __journal_abort_soft(journal, errno);
2035}
2036
2037/**
2038 * int jbd2_journal_errno () - returns the journal's error state.
2039 * @journal: journal to examine.
2040 *
2041 * This is the errno number set with jbd2_journal_abort(), the last
2042 * time the journal was mounted - if the journal was stopped
2043 * without calling abort this will be 0.
2044 *
2045 * If the journal has been aborted on this mount time -EROFS will
2046 * be returned.
2047 */
2048int jbd2_journal_errno(journal_t *journal)
2049{
2050        int err;
2051
2052        read_lock(&journal->j_state_lock);
2053        if (journal->j_flags & JBD2_ABORT)
2054                err = -EROFS;
2055        else
2056                err = journal->j_errno;
2057        read_unlock(&journal->j_state_lock);
2058        return err;
2059}
2060
2061/**
2062 * int jbd2_journal_clear_err () - clears the journal's error state
2063 * @journal: journal to act on.
2064 *
2065 * An error must be cleared or acked to take a FS out of readonly
2066 * mode.
2067 */
2068int jbd2_journal_clear_err(journal_t *journal)
2069{
2070        int err = 0;
2071
2072        write_lock(&journal->j_state_lock);
2073        if (journal->j_flags & JBD2_ABORT)
2074                err = -EROFS;
2075        else
2076                journal->j_errno = 0;
2077        write_unlock(&journal->j_state_lock);
2078        return err;
2079}
2080
2081/**
2082 * void jbd2_journal_ack_err() - Ack journal err.
2083 * @journal: journal to act on.
2084 *
2085 * An error must be cleared or acked to take a FS out of readonly
2086 * mode.
2087 */
2088void jbd2_journal_ack_err(journal_t *journal)
2089{
2090        write_lock(&journal->j_state_lock);
2091        if (journal->j_errno)
2092                journal->j_flags |= JBD2_ACK_ERR;
2093        write_unlock(&journal->j_state_lock);
2094}
2095
2096int jbd2_journal_blocks_per_page(struct inode *inode)
2097{
2098        return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
2099}
2100
2101/*
2102 * helper functions to deal with 32 or 64bit block numbers.
2103 */
2104size_t journal_tag_bytes(journal_t *journal)
2105{
2106        journal_block_tag_t tag;
2107        size_t x = 0;
2108
2109        if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
2110                x += sizeof(tag.t_checksum);
2111
2112        if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
2113                return x + JBD2_TAG_SIZE64;
2114        else
2115                return x + JBD2_TAG_SIZE32;
2116}
2117
2118/*
2119 * JBD memory management
2120 *
2121 * These functions are used to allocate block-sized chunks of memory
2122 * used for making copies of buffer_head data.  Very often it will be
2123 * page-sized chunks of data, but sometimes it will be in
2124 * sub-page-size chunks.  (For example, 16k pages on Power systems
2125 * with a 4k block file system.)  For blocks smaller than a page, we
2126 * use a SLAB allocator.  There are slab caches for each block size,
2127 * which are allocated at mount time, if necessary, and we only free
2128 * (all of) the slab caches when/if the jbd2 module is unloaded.  For
2129 * this reason we don't need to a mutex to protect access to
2130 * jbd2_slab[] allocating or releasing memory; only in
2131 * jbd2_journal_create_slab().
2132 */
2133#define JBD2_MAX_SLABS 8
2134static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS];
2135
2136static const char *jbd2_slab_names[JBD2_MAX_SLABS] = {
2137        "jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k",
2138        "jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k"
2139};
2140
2141
2142static void jbd2_journal_destroy_slabs(void)
2143{
2144        int i;
2145
2146        for (i = 0; i < JBD2_MAX_SLABS; i++) {
2147                if (jbd2_slab[i])
2148                        kmem_cache_destroy(jbd2_slab[i]);
2149                jbd2_slab[i] = NULL;
2150        }
2151}
2152
2153static int jbd2_journal_create_slab(size_t size)
2154{
2155        static DEFINE_MUTEX(jbd2_slab_create_mutex);
2156        int i = order_base_2(size) - 10;
2157        size_t slab_size;
2158
2159        if (size == PAGE_SIZE)
2160                return 0;
2161
2162        if (i >= JBD2_MAX_SLABS)
2163                return -EINVAL;
2164
2165        if (unlikely(i < 0))
2166                i = 0;
2167        mutex_lock(&jbd2_slab_create_mutex);
2168        if (jbd2_slab[i]) {
2169                mutex_unlock(&jbd2_slab_create_mutex);
2170                return 0;       /* Already created */
2171        }
2172
2173        slab_size = 1 << (i+10);
2174        jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size,
2175                                         slab_size, 0, NULL);
2176        mutex_unlock(&jbd2_slab_create_mutex);
2177        if (!jbd2_slab[i]) {
2178                printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n");
2179                return -ENOMEM;
2180        }
2181        return 0;
2182}
2183
2184static struct kmem_cache *get_slab(size_t size)
2185{
2186        int i = order_base_2(size) - 10;
2187
2188        BUG_ON(i >= JBD2_MAX_SLABS);
2189        if (unlikely(i < 0))
2190                i = 0;
2191        BUG_ON(jbd2_slab[i] == NULL);
2192        return jbd2_slab[i];
2193}
2194
2195void *jbd2_alloc(size_t size, gfp_t flags)
2196{
2197        void *ptr;
2198
2199        BUG_ON(size & (size-1)); /* Must be a power of 2 */
2200
2201        flags |= __GFP_REPEAT;
2202        if (size == PAGE_SIZE)
2203                ptr = (void *)__get_free_pages(flags, 0);
2204        else if (size > PAGE_SIZE) {
2205                int order = get_order(size);
2206
2207                if (order < 3)
2208                        ptr = (void *)__get_free_pages(flags, order);
2209                else
2210                        ptr = vmalloc(size);
2211        } else
2212                ptr = kmem_cache_alloc(get_slab(size), flags);
2213
2214        /* Check alignment; SLUB has gotten this wrong in the past,
2215         * and this can lead to user data corruption! */
2216        BUG_ON(((unsigned long) ptr) & (size-1));
2217
2218        return ptr;
2219}
2220
2221void jbd2_free(void *ptr, size_t size)
2222{
2223        if (size == PAGE_SIZE) {
2224                free_pages((unsigned long)ptr, 0);
2225                return;
2226        }
2227        if (size > PAGE_SIZE) {
2228                int order = get_order(size);
2229
2230                if (order < 3)
2231                        free_pages((unsigned long)ptr, order);
2232                else
2233                        vfree(ptr);
2234                return;
2235        }
2236        kmem_cache_free(get_slab(size), ptr);
2237};
2238
2239/*
2240 * Journal_head storage management
2241 */
2242static struct kmem_cache *jbd2_journal_head_cache;
2243#ifdef CONFIG_JBD2_DEBUG
2244static atomic_t nr_journal_heads = ATOMIC_INIT(0);
2245#endif
2246
2247static int jbd2_journal_init_journal_head_cache(void)
2248{
2249        int retval;
2250
2251        J_ASSERT(jbd2_journal_head_cache == NULL);
2252        jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
2253                                sizeof(struct journal_head),
2254                                0,              /* offset */
2255                                SLAB_TEMPORARY, /* flags */
2256                                NULL);          /* ctor */
2257        retval = 0;
2258        if (!jbd2_journal_head_cache) {
2259                retval = -ENOMEM;
2260                printk(KERN_EMERG "JBD2: no memory for journal_head cache\n");
2261        }
2262        return retval;
2263}
2264
2265static void jbd2_journal_destroy_journal_head_cache(void)
2266{
2267        if (jbd2_journal_head_cache) {
2268                kmem_cache_destroy(jbd2_journal_head_cache);
2269                jbd2_journal_head_cache = NULL;
2270        }
2271}
2272
2273/*
2274 * journal_head splicing and dicing
2275 */
2276static struct journal_head *journal_alloc_journal_head(void)
2277{
2278        struct journal_head *ret;
2279
2280#ifdef CONFIG_JBD2_DEBUG
2281        atomic_inc(&nr_journal_heads);
2282#endif
2283        ret = kmem_cache_alloc(jbd2_journal_head_cache, GFP_NOFS);
2284        if (!ret) {
2285                jbd_debug(1, "out of memory for journal_head\n");
2286                pr_notice_ratelimited("ENOMEM in %s, retrying.\n", __func__);
2287                while (!ret) {
2288                        yield();
2289                        ret = kmem_cache_alloc(jbd2_journal_head_cache, GFP_NOFS);
2290                }
2291        }
2292        return ret;
2293}
2294
2295static void journal_free_journal_head(struct journal_head *jh)
2296{
2297#ifdef CONFIG_JBD2_DEBUG
2298        atomic_dec(&nr_journal_heads);
2299        memset(jh, JBD2_POISON_FREE, sizeof(*jh));
2300#endif
2301        kmem_cache_free(jbd2_journal_head_cache, jh);
2302}
2303
2304/*
2305 * A journal_head is attached to a buffer_head whenever JBD has an
2306 * interest in the buffer.
2307 *
2308 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
2309 * is set.  This bit is tested in core kernel code where we need to take
2310 * JBD-specific actions.  Testing the zeroness of ->b_private is not reliable
2311 * there.
2312 *
2313 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
2314 *
2315 * When a buffer has its BH_JBD bit set it is immune from being released by
2316 * core kernel code, mainly via ->b_count.
2317 *
2318 * A journal_head is detached from its buffer_head when the journal_head's
2319 * b_jcount reaches zero. Running transaction (b_transaction) and checkpoint
2320 * transaction (b_cp_transaction) hold their references to b_jcount.
2321 *
2322 * Various places in the kernel want to attach a journal_head to a buffer_head
2323 * _before_ attaching the journal_head to a transaction.  To protect the
2324 * journal_head in this situation, jbd2_journal_add_journal_head elevates the
2325 * journal_head's b_jcount refcount by one.  The caller must call
2326 * jbd2_journal_put_journal_head() to undo this.
2327 *
2328 * So the typical usage would be:
2329 *
2330 *      (Attach a journal_head if needed.  Increments b_jcount)
2331 *      struct journal_head *jh = jbd2_journal_add_journal_head(bh);
2332 *      ...
2333 *      (Get another reference for transaction)
2334 *      jbd2_journal_grab_journal_head(bh);
2335 *      jh->b_transaction = xxx;
2336 *      (Put original reference)
2337 *      jbd2_journal_put_journal_head(jh);
2338 */
2339
2340/*
2341 * Give a buffer_head a journal_head.
2342 *
2343 * May sleep.
2344 */
2345struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
2346{
2347        struct journal_head *jh;
2348        struct journal_head *new_jh = NULL;
2349
2350repeat:
2351        if (!buffer_jbd(bh)) {
2352                new_jh = journal_alloc_journal_head();
2353                memset(new_jh, 0, sizeof(*new_jh));
2354        }
2355
2356        jbd_lock_bh_journal_head(bh);
2357        if (buffer_jbd(bh)) {
2358                jh = bh2jh(bh);
2359        } else {
2360                J_ASSERT_BH(bh,
2361                        (atomic_read(&bh->b_count) > 0) ||
2362                        (bh->b_page && bh->b_page->mapping));
2363
2364                if (!new_jh) {
2365                        jbd_unlock_bh_journal_head(bh);
2366                        goto repeat;
2367                }
2368
2369                jh = new_jh;
2370                new_jh = NULL;          /* We consumed it */
2371                set_buffer_jbd(bh);
2372                bh->b_private = jh;
2373                jh->b_bh = bh;
2374                get_bh(bh);
2375                BUFFER_TRACE(bh, "added journal_head");
2376        }
2377        jh->b_jcount++;
2378        jbd_unlock_bh_journal_head(bh);
2379        if (new_jh)
2380                journal_free_journal_head(new_jh);
2381        return bh->b_private;
2382}
2383
2384/*
2385 * Grab a ref against this buffer_head's journal_head.  If it ended up not
2386 * having a journal_head, return NULL
2387 */
2388struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh)
2389{
2390        struct journal_head *jh = NULL;
2391
2392        jbd_lock_bh_journal_head(bh);
2393        if (buffer_jbd(bh)) {
2394                jh = bh2jh(bh);
2395                jh->b_jcount++;
2396        }
2397        jbd_unlock_bh_journal_head(bh);
2398        return jh;
2399}
2400
2401static void __journal_remove_journal_head(struct buffer_head *bh)
2402{
2403        struct journal_head *jh = bh2jh(bh);
2404
2405        J_ASSERT_JH(jh, jh->b_jcount >= 0);
2406        J_ASSERT_JH(jh, jh->b_transaction == NULL);
2407        J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
2408        J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
2409        J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
2410        J_ASSERT_BH(bh, buffer_jbd(bh));
2411        J_ASSERT_BH(bh, jh2bh(jh) == bh);
2412        BUFFER_TRACE(bh, "remove journal_head");
2413        if (jh->b_frozen_data) {
2414                printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
2415                jbd2_free(jh->b_frozen_data, bh->b_size);
2416        }
2417        if (jh->b_committed_data) {
2418                printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
2419                jbd2_free(jh->b_committed_data, bh->b_size);
2420        }
2421        bh->b_private = NULL;
2422        jh->b_bh = NULL;        /* debug, really */
2423        clear_buffer_jbd(bh);
2424        journal_free_journal_head(jh);
2425}
2426
2427/*
2428 * Drop a reference on the passed journal_head.  If it fell to zero then
2429 * release the journal_head from the buffer_head.
2430 */
2431void jbd2_journal_put_journal_head(struct journal_head *jh)
2432{
2433        struct buffer_head *bh = jh2bh(jh);
2434
2435        jbd_lock_bh_journal_head(bh);
2436        J_ASSERT_JH(jh, jh->b_jcount > 0);
2437        --jh->b_jcount;
2438        if (!jh->b_jcount) {
2439                __journal_remove_journal_head(bh);
2440                jbd_unlock_bh_journal_head(bh);
2441                __brelse(bh);
2442        } else
2443                jbd_unlock_bh_journal_head(bh);
2444}
2445
2446/*
2447 * Initialize jbd inode head
2448 */
2449void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode)
2450{
2451        jinode->i_transaction = NULL;
2452        jinode->i_next_transaction = NULL;
2453        jinode->i_vfs_inode = inode;
2454        jinode->i_flags = 0;
2455        INIT_LIST_HEAD(&jinode->i_list);
2456}
2457
2458/*
2459 * Function to be called before we start removing inode from memory (i.e.,
2460 * clear_inode() is a fine place to be called from). It removes inode from
2461 * transaction's lists.
2462 */
2463void jbd2_journal_release_jbd_inode(journal_t *journal,
2464                                    struct jbd2_inode *jinode)
2465{
2466        if (!journal)
2467                return;
2468restart:
2469        spin_lock(&journal->j_list_lock);
2470        /* Is commit writing out inode - we have to wait */
2471        if (test_bit(__JI_COMMIT_RUNNING, &jinode->i_flags)) {
2472                wait_queue_head_t *wq;
2473                DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
2474                wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
2475                prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
2476                spin_unlock(&journal->j_list_lock);
2477                schedule();
2478                finish_wait(wq, &wait.wait);
2479                goto restart;
2480        }
2481
2482        if (jinode->i_transaction) {
2483                list_del(&jinode->i_list);
2484                jinode->i_transaction = NULL;
2485        }
2486        spin_unlock(&journal->j_list_lock);
2487}
2488
2489/*
2490 * debugfs tunables
2491 */
2492#ifdef CONFIG_JBD2_DEBUG
2493u8 jbd2_journal_enable_debug __read_mostly;
2494EXPORT_SYMBOL(jbd2_journal_enable_debug);
2495
2496#define JBD2_DEBUG_NAME "jbd2-debug"
2497
2498static struct dentry *jbd2_debugfs_dir;
2499static struct dentry *jbd2_debug;
2500
2501static void __init jbd2_create_debugfs_entry(void)
2502{
2503        jbd2_debugfs_dir = debugfs_create_dir("jbd2", NULL);
2504        if (jbd2_debugfs_dir)
2505                jbd2_debug = debugfs_create_u8(JBD2_DEBUG_NAME,
2506                                               S_IRUGO | S_IWUSR,
2507                                               jbd2_debugfs_dir,
2508                                               &jbd2_journal_enable_debug);
2509}
2510
2511static void __exit jbd2_remove_debugfs_entry(void)
2512{
2513        debugfs_remove(jbd2_debug);
2514        debugfs_remove(jbd2_debugfs_dir);
2515}
2516
2517#else
2518
2519static void __init jbd2_create_debugfs_entry(void)
2520{
2521}
2522
2523static void __exit jbd2_remove_debugfs_entry(void)
2524{
2525}
2526
2527#endif
2528
2529#ifdef CONFIG_PROC_FS
2530
2531#define JBD2_STATS_PROC_NAME "fs/jbd2"
2532
2533static void __init jbd2_create_jbd_stats_proc_entry(void)
2534{
2535        proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL);
2536}
2537
2538static void __exit jbd2_remove_jbd_stats_proc_entry(void)
2539{
2540        if (proc_jbd2_stats)
2541                remove_proc_entry(JBD2_STATS_PROC_NAME, NULL);
2542}
2543
2544#else
2545
2546#define jbd2_create_jbd_stats_proc_entry() do {} while (0)
2547#define jbd2_remove_jbd_stats_proc_entry() do {} while (0)
2548
2549#endif
2550
2551struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
2552
2553static int __init jbd2_journal_init_handle_cache(void)
2554{
2555        jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
2556        if (jbd2_handle_cache == NULL) {
2557                printk(KERN_EMERG "JBD2: failed to create handle cache\n");
2558                return -ENOMEM;
2559        }
2560        jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0);
2561        if (jbd2_inode_cache == NULL) {
2562                printk(KERN_EMERG "JBD2: failed to create inode cache\n");
2563                kmem_cache_destroy(jbd2_handle_cache);
2564                return -ENOMEM;
2565        }
2566        return 0;
2567}
2568
2569static void jbd2_journal_destroy_handle_cache(void)
2570{
2571        if (jbd2_handle_cache)
2572                kmem_cache_destroy(jbd2_handle_cache);
2573        if (jbd2_inode_cache)
2574                kmem_cache_destroy(jbd2_inode_cache);
2575
2576}
2577
2578/*
2579 * Module startup and shutdown
2580 */
2581
2582static int __init journal_init_caches(void)
2583{
2584        int ret;
2585
2586        ret = jbd2_journal_init_revoke_caches();
2587        if (ret == 0)
2588                ret = jbd2_journal_init_journal_head_cache();
2589        if (ret == 0)
2590                ret = jbd2_journal_init_handle_cache();
2591        if (ret == 0)
2592                ret = jbd2_journal_init_transaction_cache();
2593        return ret;
2594}
2595
2596static void jbd2_journal_destroy_caches(void)
2597{
2598        jbd2_journal_destroy_revoke_caches();
2599        jbd2_journal_destroy_journal_head_cache();
2600        jbd2_journal_destroy_handle_cache();
2601        jbd2_journal_destroy_transaction_cache();
2602        jbd2_journal_destroy_slabs();
2603}
2604
2605static int __init journal_init(void)
2606{
2607        int ret;
2608
2609        BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
2610
2611        ret = journal_init_caches();
2612        if (ret == 0) {
2613                jbd2_create_debugfs_entry();
2614                jbd2_create_jbd_stats_proc_entry();
2615        } else {
2616                jbd2_journal_destroy_caches();
2617        }
2618        return ret;
2619}
2620
2621static void __exit journal_exit(void)
2622{
2623#ifdef CONFIG_JBD2_DEBUG
2624        int n = atomic_read(&nr_journal_heads);
2625        if (n)
2626                printk(KERN_EMERG "JBD2: leaked %d journal_heads!\n", n);
2627#endif
2628        jbd2_remove_debugfs_entry();
2629        jbd2_remove_jbd_stats_proc_entry();
2630        jbd2_journal_destroy_caches();
2631}
2632
2633MODULE_LICENSE("GPL");
2634module_init(journal_init);
2635module_exit(journal_exit);
2636
2637
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