linux/fs/jbd2/checkpoint.c
<<
>>
Prefs
   1/*
   2 * linux/fs/jbd2/checkpoint.c
   3 *
   4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
   5 *
   6 * Copyright 1999 Red Hat Software --- 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 * Checkpoint routines for the generic filesystem journaling code.
  13 * Part of the ext2fs journaling system.
  14 *
  15 * Checkpointing is the process of ensuring that a section of the log is
  16 * committed fully to disk, so that that portion of the log can be
  17 * reused.
  18 */
  19
  20#include <linux/time.h>
  21#include <linux/fs.h>
  22#include <linux/jbd2.h>
  23#include <linux/errno.h>
  24#include <linux/slab.h>
  25#include <linux/blkdev.h>
  26#include <trace/events/jbd2.h>
  27
  28/*
  29 * Unlink a buffer from a transaction checkpoint list.
  30 *
  31 * Called with j_list_lock held.
  32 */
  33static inline void __buffer_unlink_first(struct journal_head *jh)
  34{
  35        transaction_t *transaction = jh->b_cp_transaction;
  36
  37        jh->b_cpnext->b_cpprev = jh->b_cpprev;
  38        jh->b_cpprev->b_cpnext = jh->b_cpnext;
  39        if (transaction->t_checkpoint_list == jh) {
  40                transaction->t_checkpoint_list = jh->b_cpnext;
  41                if (transaction->t_checkpoint_list == jh)
  42                        transaction->t_checkpoint_list = NULL;
  43        }
  44}
  45
  46/*
  47 * Unlink a buffer from a transaction checkpoint(io) list.
  48 *
  49 * Called with j_list_lock held.
  50 */
  51static inline void __buffer_unlink(struct journal_head *jh)
  52{
  53        transaction_t *transaction = jh->b_cp_transaction;
  54
  55        __buffer_unlink_first(jh);
  56        if (transaction->t_checkpoint_io_list == jh) {
  57                transaction->t_checkpoint_io_list = jh->b_cpnext;
  58                if (transaction->t_checkpoint_io_list == jh)
  59                        transaction->t_checkpoint_io_list = NULL;
  60        }
  61}
  62
  63/*
  64 * Move a buffer from the checkpoint list to the checkpoint io list
  65 *
  66 * Called with j_list_lock held
  67 */
  68static inline void __buffer_relink_io(struct journal_head *jh)
  69{
  70        transaction_t *transaction = jh->b_cp_transaction;
  71
  72        __buffer_unlink_first(jh);
  73
  74        if (!transaction->t_checkpoint_io_list) {
  75                jh->b_cpnext = jh->b_cpprev = jh;
  76        } else {
  77                jh->b_cpnext = transaction->t_checkpoint_io_list;
  78                jh->b_cpprev = transaction->t_checkpoint_io_list->b_cpprev;
  79                jh->b_cpprev->b_cpnext = jh;
  80                jh->b_cpnext->b_cpprev = jh;
  81        }
  82        transaction->t_checkpoint_io_list = jh;
  83}
  84
  85/*
  86 * Try to release a checkpointed buffer from its transaction.
  87 * Returns 1 if we released it and 2 if we also released the
  88 * whole transaction.
  89 *
  90 * Requires j_list_lock
  91 */
  92static int __try_to_free_cp_buf(struct journal_head *jh)
  93{
  94        int ret = 0;
  95        struct buffer_head *bh = jh2bh(jh);
  96
  97        if (jh->b_transaction == NULL && !buffer_locked(bh) &&
  98            !buffer_dirty(bh) && !buffer_write_io_error(bh)) {
  99                /*
 100                 * Get our reference so that bh cannot be freed before
 101                 * we unlock it
 102                 */
 103                get_bh(bh);
 104                JBUFFER_TRACE(jh, "remove from checkpoint list");
 105                ret = __jbd2_journal_remove_checkpoint(jh) + 1;
 106                BUFFER_TRACE(bh, "release");
 107                __brelse(bh);
 108        }
 109        return ret;
 110}
 111
 112/*
 113 * __jbd2_log_wait_for_space: wait until there is space in the journal.
 114 *
 115 * Called under j-state_lock *only*.  It will be unlocked if we have to wait
 116 * for a checkpoint to free up some space in the log.
 117 */
 118void __jbd2_log_wait_for_space(journal_t *journal)
 119{
 120        int nblocks, space_left;
 121        /* assert_spin_locked(&journal->j_state_lock); */
 122
 123        nblocks = jbd2_space_needed(journal);
 124        while (jbd2_log_space_left(journal) < nblocks) {
 125                if (journal->j_flags & JBD2_ABORT)
 126                        return;
 127                write_unlock(&journal->j_state_lock);
 128                mutex_lock(&journal->j_checkpoint_mutex);
 129
 130                /*
 131                 * Test again, another process may have checkpointed while we
 132                 * were waiting for the checkpoint lock. If there are no
 133                 * transactions ready to be checkpointed, try to recover
 134                 * journal space by calling cleanup_journal_tail(), and if
 135                 * that doesn't work, by waiting for the currently committing
 136                 * transaction to complete.  If there is absolutely no way
 137                 * to make progress, this is either a BUG or corrupted
 138                 * filesystem, so abort the journal and leave a stack
 139                 * trace for forensic evidence.
 140                 */
 141                write_lock(&journal->j_state_lock);
 142                spin_lock(&journal->j_list_lock);
 143                nblocks = jbd2_space_needed(journal);
 144                space_left = jbd2_log_space_left(journal);
 145                if (space_left < nblocks) {
 146                        int chkpt = journal->j_checkpoint_transactions != NULL;
 147                        tid_t tid = 0;
 148
 149                        if (journal->j_committing_transaction)
 150                                tid = journal->j_committing_transaction->t_tid;
 151                        spin_unlock(&journal->j_list_lock);
 152                        write_unlock(&journal->j_state_lock);
 153                        if (chkpt) {
 154                                jbd2_log_do_checkpoint(journal);
 155                        } else if (jbd2_cleanup_journal_tail(journal) == 0) {
 156                                /* We were able to recover space; yay! */
 157                                ;
 158                        } else if (tid) {
 159                                /*
 160                                 * jbd2_journal_commit_transaction() may want
 161                                 * to take the checkpoint_mutex if JBD2_FLUSHED
 162                                 * is set.  So we need to temporarily drop it.
 163                                 */
 164                                mutex_unlock(&journal->j_checkpoint_mutex);
 165                                jbd2_log_wait_commit(journal, tid);
 166                                write_lock(&journal->j_state_lock);
 167                                continue;
 168                        } else {
 169                                printk(KERN_ERR "%s: needed %d blocks and "
 170                                       "only had %d space available\n",
 171                                       __func__, nblocks, space_left);
 172                                printk(KERN_ERR "%s: no way to get more "
 173                                       "journal space in %s\n", __func__,
 174                                       journal->j_devname);
 175                                WARN_ON(1);
 176                                jbd2_journal_abort(journal, 0);
 177                        }
 178                        write_lock(&journal->j_state_lock);
 179                } else {
 180                        spin_unlock(&journal->j_list_lock);
 181                }
 182                mutex_unlock(&journal->j_checkpoint_mutex);
 183        }
 184}
 185
 186/*
 187 * Clean up transaction's list of buffers submitted for io.
 188 * We wait for any pending IO to complete and remove any clean
 189 * buffers. Note that we take the buffers in the opposite ordering
 190 * from the one in which they were submitted for IO.
 191 *
 192 * Return 0 on success, and return <0 if some buffers have failed
 193 * to be written out.
 194 *
 195 * Called with j_list_lock held.
 196 */
 197static int __wait_cp_io(journal_t *journal, transaction_t *transaction)
 198{
 199        struct journal_head *jh;
 200        struct buffer_head *bh;
 201        tid_t this_tid;
 202        int released = 0;
 203        int ret = 0;
 204
 205        this_tid = transaction->t_tid;
 206restart:
 207        /* Did somebody clean up the transaction in the meanwhile? */
 208        if (journal->j_checkpoint_transactions != transaction ||
 209                        transaction->t_tid != this_tid)
 210                return ret;
 211        while (!released && transaction->t_checkpoint_io_list) {
 212                jh = transaction->t_checkpoint_io_list;
 213                bh = jh2bh(jh);
 214                get_bh(bh);
 215                if (buffer_locked(bh)) {
 216                        spin_unlock(&journal->j_list_lock);
 217                        wait_on_buffer(bh);
 218                        /* the journal_head may have gone by now */
 219                        BUFFER_TRACE(bh, "brelse");
 220                        __brelse(bh);
 221                        spin_lock(&journal->j_list_lock);
 222                        goto restart;
 223                }
 224                if (unlikely(buffer_write_io_error(bh)))
 225                        ret = -EIO;
 226
 227                /*
 228                 * Now in whatever state the buffer currently is, we know that
 229                 * it has been written out and so we can drop it from the list
 230                 */
 231                released = __jbd2_journal_remove_checkpoint(jh);
 232                __brelse(bh);
 233        }
 234
 235        return ret;
 236}
 237
 238static void
 239__flush_batch(journal_t *journal, int *batch_count)
 240{
 241        int i;
 242        struct blk_plug plug;
 243
 244        blk_start_plug(&plug);
 245        for (i = 0; i < *batch_count; i++)
 246                write_dirty_buffer(journal->j_chkpt_bhs[i], WRITE_SYNC);
 247        blk_finish_plug(&plug);
 248
 249        for (i = 0; i < *batch_count; i++) {
 250                struct buffer_head *bh = journal->j_chkpt_bhs[i];
 251                BUFFER_TRACE(bh, "brelse");
 252                __brelse(bh);
 253        }
 254        *batch_count = 0;
 255}
 256
 257/*
 258 * Try to flush one buffer from the checkpoint list to disk.
 259 *
 260 * Return 1 if something happened which requires us to abort the current
 261 * scan of the checkpoint list.  Return <0 if the buffer has failed to
 262 * be written out.
 263 *
 264 * Called with j_list_lock held and drops it if 1 is returned
 265 */
 266static int __process_buffer(journal_t *journal, struct journal_head *jh,
 267                            int *batch_count, transaction_t *transaction)
 268{
 269        struct buffer_head *bh = jh2bh(jh);
 270        int ret = 0;
 271
 272        if (buffer_locked(bh)) {
 273                get_bh(bh);
 274                spin_unlock(&journal->j_list_lock);
 275                wait_on_buffer(bh);
 276                /* the journal_head may have gone by now */
 277                BUFFER_TRACE(bh, "brelse");
 278                __brelse(bh);
 279                ret = 1;
 280        } else if (jh->b_transaction != NULL) {
 281                transaction_t *t = jh->b_transaction;
 282                tid_t tid = t->t_tid;
 283
 284                transaction->t_chp_stats.cs_forced_to_close++;
 285                spin_unlock(&journal->j_list_lock);
 286                if (unlikely(journal->j_flags & JBD2_UNMOUNT))
 287                        /*
 288                         * The journal thread is dead; so starting and
 289                         * waiting for a commit to finish will cause
 290                         * us to wait for a _very_ long time.
 291                         */
 292                        printk(KERN_ERR "JBD2: %s: "
 293                               "Waiting for Godot: block %llu\n",
 294                               journal->j_devname,
 295                               (unsigned long long) bh->b_blocknr);
 296                jbd2_log_start_commit(journal, tid);
 297                jbd2_log_wait_commit(journal, tid);
 298                ret = 1;
 299        } else if (!buffer_dirty(bh)) {
 300                ret = 1;
 301                if (unlikely(buffer_write_io_error(bh)))
 302                        ret = -EIO;
 303                get_bh(bh);
 304                BUFFER_TRACE(bh, "remove from checkpoint");
 305                __jbd2_journal_remove_checkpoint(jh);
 306                spin_unlock(&journal->j_list_lock);
 307                __brelse(bh);
 308        } else {
 309                /*
 310                 * Important: we are about to write the buffer, and
 311                 * possibly block, while still holding the journal lock.
 312                 * We cannot afford to let the transaction logic start
 313                 * messing around with this buffer before we write it to
 314                 * disk, as that would break recoverability.
 315                 */
 316                BUFFER_TRACE(bh, "queue");
 317                get_bh(bh);
 318                J_ASSERT_BH(bh, !buffer_jwrite(bh));
 319                journal->j_chkpt_bhs[*batch_count] = bh;
 320                __buffer_relink_io(jh);
 321                transaction->t_chp_stats.cs_written++;
 322                (*batch_count)++;
 323                if (*batch_count == JBD2_NR_BATCH) {
 324                        spin_unlock(&journal->j_list_lock);
 325                        __flush_batch(journal, batch_count);
 326                        ret = 1;
 327                }
 328        }
 329        return ret;
 330}
 331
 332/*
 333 * Perform an actual checkpoint. We take the first transaction on the
 334 * list of transactions to be checkpointed and send all its buffers
 335 * to disk. We submit larger chunks of data at once.
 336 *
 337 * The journal should be locked before calling this function.
 338 * Called with j_checkpoint_mutex held.
 339 */
 340int jbd2_log_do_checkpoint(journal_t *journal)
 341{
 342        transaction_t *transaction;
 343        tid_t this_tid;
 344        int result;
 345
 346        jbd_debug(1, "Start checkpoint\n");
 347
 348        /*
 349         * First thing: if there are any transactions in the log which
 350         * don't need checkpointing, just eliminate them from the
 351         * journal straight away.
 352         */
 353        result = jbd2_cleanup_journal_tail(journal);
 354        trace_jbd2_checkpoint(journal, result);
 355        jbd_debug(1, "cleanup_journal_tail returned %d\n", result);
 356        if (result <= 0)
 357                return result;
 358
 359        /*
 360         * OK, we need to start writing disk blocks.  Take one transaction
 361         * and write it.
 362         */
 363        result = 0;
 364        spin_lock(&journal->j_list_lock);
 365        if (!journal->j_checkpoint_transactions)
 366                goto out;
 367        transaction = journal->j_checkpoint_transactions;
 368        if (transaction->t_chp_stats.cs_chp_time == 0)
 369                transaction->t_chp_stats.cs_chp_time = jiffies;
 370        this_tid = transaction->t_tid;
 371restart:
 372        /*
 373         * If someone cleaned up this transaction while we slept, we're
 374         * done (maybe it's a new transaction, but it fell at the same
 375         * address).
 376         */
 377        if (journal->j_checkpoint_transactions == transaction &&
 378                        transaction->t_tid == this_tid) {
 379                int batch_count = 0;
 380                struct journal_head *jh;
 381                int retry = 0, err;
 382
 383                while (!retry && transaction->t_checkpoint_list) {
 384                        jh = transaction->t_checkpoint_list;
 385                        retry = __process_buffer(journal, jh, &batch_count,
 386                                                 transaction);
 387                        if (retry < 0 && !result)
 388                                result = retry;
 389                        if (!retry && (need_resched() ||
 390                                spin_needbreak(&journal->j_list_lock))) {
 391                                spin_unlock(&journal->j_list_lock);
 392                                retry = 1;
 393                                break;
 394                        }
 395                }
 396
 397                if (batch_count) {
 398                        if (!retry) {
 399                                spin_unlock(&journal->j_list_lock);
 400                                retry = 1;
 401                        }
 402                        __flush_batch(journal, &batch_count);
 403                }
 404
 405                if (retry) {
 406                        spin_lock(&journal->j_list_lock);
 407                        goto restart;
 408                }
 409                /*
 410                 * Now we have cleaned up the first transaction's checkpoint
 411                 * list. Let's clean up the second one
 412                 */
 413                err = __wait_cp_io(journal, transaction);
 414                if (!result)
 415                        result = err;
 416        }
 417out:
 418        spin_unlock(&journal->j_list_lock);
 419        if (result < 0)
 420                jbd2_journal_abort(journal, result);
 421        else
 422                result = jbd2_cleanup_journal_tail(journal);
 423
 424        return (result < 0) ? result : 0;
 425}
 426
 427/*
 428 * Check the list of checkpoint transactions for the journal to see if
 429 * we have already got rid of any since the last update of the log tail
 430 * in the journal superblock.  If so, we can instantly roll the
 431 * superblock forward to remove those transactions from the log.
 432 *
 433 * Return <0 on error, 0 on success, 1 if there was nothing to clean up.
 434 *
 435 * Called with the journal lock held.
 436 *
 437 * This is the only part of the journaling code which really needs to be
 438 * aware of transaction aborts.  Checkpointing involves writing to the
 439 * main filesystem area rather than to the journal, so it can proceed
 440 * even in abort state, but we must not update the super block if
 441 * checkpointing may have failed.  Otherwise, we would lose some metadata
 442 * buffers which should be written-back to the filesystem.
 443 */
 444
 445int jbd2_cleanup_journal_tail(journal_t *journal)
 446{
 447        tid_t           first_tid;
 448        unsigned long   blocknr;
 449
 450        if (is_journal_aborted(journal))
 451                return 1;
 452
 453        if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr))
 454                return 1;
 455        J_ASSERT(blocknr != 0);
 456
 457        /*
 458         * We need to make sure that any blocks that were recently written out
 459         * --- perhaps by jbd2_log_do_checkpoint() --- are flushed out before
 460         * we drop the transactions from the journal. It's unlikely this will
 461         * be necessary, especially with an appropriately sized journal, but we
 462         * need this to guarantee correctness.  Fortunately
 463         * jbd2_cleanup_journal_tail() doesn't get called all that often.
 464         */
 465        if (journal->j_flags & JBD2_BARRIER)
 466                blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
 467
 468        __jbd2_update_log_tail(journal, first_tid, blocknr);
 469        return 0;
 470}
 471
 472
 473/* Checkpoint list management */
 474
 475/*
 476 * journal_clean_one_cp_list
 477 *
 478 * Find all the written-back checkpoint buffers in the given list and
 479 * release them.
 480 *
 481 * Called with the journal locked.
 482 * Called with j_list_lock held.
 483 * Returns number of buffers reaped (for debug)
 484 */
 485
 486static int journal_clean_one_cp_list(struct journal_head *jh, int *released)
 487{
 488        struct journal_head *last_jh;
 489        struct journal_head *next_jh = jh;
 490        int ret, freed = 0;
 491
 492        *released = 0;
 493        if (!jh)
 494                return 0;
 495
 496        last_jh = jh->b_cpprev;
 497        do {
 498                jh = next_jh;
 499                next_jh = jh->b_cpnext;
 500                ret = __try_to_free_cp_buf(jh);
 501                if (ret) {
 502                        freed++;
 503                        if (ret == 2) {
 504                                *released = 1;
 505                                return freed;
 506                        }
 507                }
 508                /*
 509                 * This function only frees up some memory
 510                 * if possible so we dont have an obligation
 511                 * to finish processing. Bail out if preemption
 512                 * requested:
 513                 */
 514                if (need_resched())
 515                        return freed;
 516        } while (jh != last_jh);
 517
 518        return freed;
 519}
 520
 521/*
 522 * journal_clean_checkpoint_list
 523 *
 524 * Find all the written-back checkpoint buffers in the journal and release them.
 525 *
 526 * Called with the journal locked.
 527 * Called with j_list_lock held.
 528 * Returns number of buffers reaped (for debug)
 529 */
 530
 531int __jbd2_journal_clean_checkpoint_list(journal_t *journal)
 532{
 533        transaction_t *transaction, *last_transaction, *next_transaction;
 534        int ret = 0;
 535        int released;
 536
 537        transaction = journal->j_checkpoint_transactions;
 538        if (!transaction)
 539                goto out;
 540
 541        last_transaction = transaction->t_cpprev;
 542        next_transaction = transaction;
 543        do {
 544                transaction = next_transaction;
 545                next_transaction = transaction->t_cpnext;
 546                ret += journal_clean_one_cp_list(transaction->
 547                                t_checkpoint_list, &released);
 548                /*
 549                 * This function only frees up some memory if possible so we
 550                 * dont have an obligation to finish processing. Bail out if
 551                 * preemption requested:
 552                 */
 553                if (need_resched())
 554                        goto out;
 555                if (released)
 556                        continue;
 557                /*
 558                 * It is essential that we are as careful as in the case of
 559                 * t_checkpoint_list with removing the buffer from the list as
 560                 * we can possibly see not yet submitted buffers on io_list
 561                 */
 562                ret += journal_clean_one_cp_list(transaction->
 563                                t_checkpoint_io_list, &released);
 564                if (need_resched())
 565                        goto out;
 566        } while (transaction != last_transaction);
 567out:
 568        return ret;
 569}
 570
 571/*
 572 * journal_remove_checkpoint: called after a buffer has been committed
 573 * to disk (either by being write-back flushed to disk, or being
 574 * committed to the log).
 575 *
 576 * We cannot safely clean a transaction out of the log until all of the
 577 * buffer updates committed in that transaction have safely been stored
 578 * elsewhere on disk.  To achieve this, all of the buffers in a
 579 * transaction need to be maintained on the transaction's checkpoint
 580 * lists until they have been rewritten, at which point this function is
 581 * called to remove the buffer from the existing transaction's
 582 * checkpoint lists.
 583 *
 584 * The function returns 1 if it frees the transaction, 0 otherwise.
 585 * The function can free jh and bh.
 586 *
 587 * This function is called with j_list_lock held.
 588 */
 589int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
 590{
 591        struct transaction_chp_stats_s *stats;
 592        transaction_t *transaction;
 593        journal_t *journal;
 594        int ret = 0;
 595
 596        JBUFFER_TRACE(jh, "entry");
 597
 598        if ((transaction = jh->b_cp_transaction) == NULL) {
 599                JBUFFER_TRACE(jh, "not on transaction");
 600                goto out;
 601        }
 602        journal = transaction->t_journal;
 603
 604        JBUFFER_TRACE(jh, "removing from transaction");
 605        __buffer_unlink(jh);
 606        jh->b_cp_transaction = NULL;
 607        jbd2_journal_put_journal_head(jh);
 608
 609        if (transaction->t_checkpoint_list != NULL ||
 610            transaction->t_checkpoint_io_list != NULL)
 611                goto out;
 612
 613        /*
 614         * There is one special case to worry about: if we have just pulled the
 615         * buffer off a running or committing transaction's checkpoing list,
 616         * then even if the checkpoint list is empty, the transaction obviously
 617         * cannot be dropped!
 618         *
 619         * The locking here around t_state is a bit sleazy.
 620         * See the comment at the end of jbd2_journal_commit_transaction().
 621         */
 622        if (transaction->t_state != T_FINISHED)
 623                goto out;
 624
 625        /* OK, that was the last buffer for the transaction: we can now
 626           safely remove this transaction from the log */
 627        stats = &transaction->t_chp_stats;
 628        if (stats->cs_chp_time)
 629                stats->cs_chp_time = jbd2_time_diff(stats->cs_chp_time,
 630                                                    jiffies);
 631        trace_jbd2_checkpoint_stats(journal->j_fs_dev->bd_dev,
 632                                    transaction->t_tid, stats);
 633
 634        __jbd2_journal_drop_transaction(journal, transaction);
 635        jbd2_journal_free_transaction(transaction);
 636        ret = 1;
 637out:
 638        return ret;
 639}
 640
 641/*
 642 * journal_insert_checkpoint: put a committed buffer onto a checkpoint
 643 * list so that we know when it is safe to clean the transaction out of
 644 * the log.
 645 *
 646 * Called with the journal locked.
 647 * Called with j_list_lock held.
 648 */
 649void __jbd2_journal_insert_checkpoint(struct journal_head *jh,
 650                               transaction_t *transaction)
 651{
 652        JBUFFER_TRACE(jh, "entry");
 653        J_ASSERT_JH(jh, buffer_dirty(jh2bh(jh)) || buffer_jbddirty(jh2bh(jh)));
 654        J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
 655
 656        /* Get reference for checkpointing transaction */
 657        jbd2_journal_grab_journal_head(jh2bh(jh));
 658        jh->b_cp_transaction = transaction;
 659
 660        if (!transaction->t_checkpoint_list) {
 661                jh->b_cpnext = jh->b_cpprev = jh;
 662        } else {
 663                jh->b_cpnext = transaction->t_checkpoint_list;
 664                jh->b_cpprev = transaction->t_checkpoint_list->b_cpprev;
 665                jh->b_cpprev->b_cpnext = jh;
 666                jh->b_cpnext->b_cpprev = jh;
 667        }
 668        transaction->t_checkpoint_list = jh;
 669}
 670
 671/*
 672 * We've finished with this transaction structure: adios...
 673 *
 674 * The transaction must have no links except for the checkpoint by this
 675 * point.
 676 *
 677 * Called with the journal locked.
 678 * Called with j_list_lock held.
 679 */
 680
 681void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transaction)
 682{
 683        assert_spin_locked(&journal->j_list_lock);
 684        if (transaction->t_cpnext) {
 685                transaction->t_cpnext->t_cpprev = transaction->t_cpprev;
 686                transaction->t_cpprev->t_cpnext = transaction->t_cpnext;
 687                if (journal->j_checkpoint_transactions == transaction)
 688                        journal->j_checkpoint_transactions =
 689                                transaction->t_cpnext;
 690                if (journal->j_checkpoint_transactions == transaction)
 691                        journal->j_checkpoint_transactions = NULL;
 692        }
 693
 694        J_ASSERT(transaction->t_state == T_FINISHED);
 695        J_ASSERT(transaction->t_buffers == NULL);
 696        J_ASSERT(transaction->t_forget == NULL);
 697        J_ASSERT(transaction->t_shadow_list == NULL);
 698        J_ASSERT(transaction->t_checkpoint_list == NULL);
 699        J_ASSERT(transaction->t_checkpoint_io_list == NULL);
 700        J_ASSERT(atomic_read(&transaction->t_updates) == 0);
 701        J_ASSERT(journal->j_committing_transaction != transaction);
 702        J_ASSERT(journal->j_running_transaction != transaction);
 703
 704        trace_jbd2_drop_transaction(journal, transaction);
 705
 706        jbd_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid);
 707}
 708
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.