new file mode 100644
@@ -0,0 +1,718 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * linux/fs/jbd2/checkpoint.c
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
+ *
+ * Copyright 1999 Red Hat Software --- All Rights Reserved
+ *
+ * Checkpoint routines for the generic filesystem journaling code.
+ * Part of the ext2fs journaling system.
+ *
+ * Checkpointing is the process of ensuring that a section of the log is
+ * committed fully to disk, so that that portion of the log can be
+ * reused.
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+#include <trace/events/jbd2.h>
+
+/*
+ * Unlink a buffer from a transaction checkpoint list.
+ *
+ * Called with j_list_lock held.
+ */
+static inline void __buffer_unlink(struct journal_head *jh)
+{
+ transaction_t *transaction = jh->b_cp_transaction;
+
+ jh->b_cpnext->b_cpprev = jh->b_cpprev;
+ jh->b_cpprev->b_cpnext = jh->b_cpnext;
+ if (transaction->t_checkpoint_list == jh) {
+ transaction->t_checkpoint_list = jh->b_cpnext;
+ if (transaction->t_checkpoint_list == jh)
+ transaction->t_checkpoint_list = NULL;
+ }
+}
+
+/*
+ * __jbd2_log_wait_for_space: wait until there is space in the journal.
+ *
+ * Called under j-state_lock *only*. It will be unlocked if we have to wait
+ * for a checkpoint to free up some space in the log.
+ */
+void __jbd2_log_wait_for_space(journal_t *journal)
+__acquires(&journal->j_state_lock)
+__releases(&journal->j_state_lock)
+{
+ int nblocks, space_left;
+ /* assert_spin_locked(&journal->j_state_lock); */
+
+ nblocks = journal->j_max_transaction_buffers;
+ while (jbd2_log_space_left(journal) < nblocks) {
+ write_unlock(&journal->j_state_lock);
+ mutex_lock_io(&journal->j_checkpoint_mutex);
+
+ /*
+ * Test again, another process may have checkpointed while we
+ * were waiting for the checkpoint lock. If there are no
+ * transactions ready to be checkpointed, try to recover
+ * journal space by calling cleanup_journal_tail(), and if
+ * that doesn't work, by waiting for the currently committing
+ * transaction to complete. If there is absolutely no way
+ * to make progress, this is either a BUG or corrupted
+ * filesystem, so abort the journal and leave a stack
+ * trace for forensic evidence.
+ */
+ write_lock(&journal->j_state_lock);
+ if (journal->j_flags & JBD2_ABORT) {
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ return;
+ }
+ spin_lock(&journal->j_list_lock);
+ space_left = jbd2_log_space_left(journal);
+ if (space_left < nblocks) {
+ int chkpt = journal->j_checkpoint_transactions != NULL;
+ tid_t tid = 0;
+ bool has_transaction = false;
+
+ if (journal->j_committing_transaction) {
+ tid = journal->j_committing_transaction->t_tid;
+ has_transaction = true;
+ }
+ spin_unlock(&journal->j_list_lock);
+ write_unlock(&journal->j_state_lock);
+ if (chkpt) {
+ jbd2_log_do_checkpoint(journal);
+ } else if (jbd2_cleanup_journal_tail(journal) <= 0) {
+ /*
+ * We were able to recover space or the
+ * journal was aborted due to an error.
+ */
+ ;
+ } else if (has_transaction) {
+ /*
+ * jbd2_journal_commit_transaction() may want
+ * to take the checkpoint_mutex if JBD2_FLUSHED
+ * is set. So we need to temporarily drop it.
+ */
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ jbd2_log_wait_commit(journal, tid);
+ write_lock(&journal->j_state_lock);
+ continue;
+ } else {
+ printk(KERN_ERR "%s: needed %d blocks and "
+ "only had %d space available\n",
+ __func__, nblocks, space_left);
+ printk(KERN_ERR "%s: no way to get more "
+ "journal space in %s\n", __func__,
+ journal->j_devname);
+ WARN_ON(1);
+ jbd2_journal_abort(journal, -EIO);
+ }
+ write_lock(&journal->j_state_lock);
+ } else {
+ spin_unlock(&journal->j_list_lock);
+ }
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ }
+}
+
+static void
+__flush_batch(journal_t *journal, int *batch_count)
+{
+ int i;
+ struct blk_plug plug;
+
+ blk_start_plug(&plug);
+ for (i = 0; i < *batch_count; i++)
+ write_dirty_buffer(journal->j_chkpt_bhs[i], JBD2_JOURNAL_REQ_FLAGS);
+ blk_finish_plug(&plug);
+
+ for (i = 0; i < *batch_count; i++) {
+ struct buffer_head *bh = journal->j_chkpt_bhs[i];
+ BUFFER_TRACE(bh, "brelse");
+ __brelse(bh);
+ journal->j_chkpt_bhs[i] = NULL;
+ }
+ *batch_count = 0;
+}
+
+/*
+ * Perform an actual checkpoint. We take the first transaction on the
+ * list of transactions to be checkpointed and send all its buffers
+ * to disk. We submit larger chunks of data at once.
+ *
+ * The journal should be locked before calling this function.
+ * Called with j_checkpoint_mutex held.
+ */
+int jbd2_log_do_checkpoint(journal_t *journal)
+{
+ struct journal_head *jh;
+ struct buffer_head *bh;
+ transaction_t *transaction;
+ tid_t this_tid;
+ int result, batch_count = 0;
+
+ jbd2_debug(1, "Start checkpoint\n");
+
+ /*
+ * First thing: if there are any transactions in the log which
+ * don't need checkpointing, just eliminate them from the
+ * journal straight away.
+ */
+ result = jbd2_cleanup_journal_tail(journal);
+ trace_jbd2_checkpoint(journal, result);
+ jbd2_debug(1, "cleanup_journal_tail returned %d\n", result);
+ if (result <= 0)
+ return result;
+
+ /*
+ * OK, we need to start writing disk blocks. Take one transaction
+ * and write it.
+ */
+ spin_lock(&journal->j_list_lock);
+ if (!journal->j_checkpoint_transactions)
+ goto out;
+ transaction = journal->j_checkpoint_transactions;
+ if (transaction->t_chp_stats.cs_chp_time == 0)
+ transaction->t_chp_stats.cs_chp_time = jiffies;
+ this_tid = transaction->t_tid;
+restart:
+ /*
+ * If someone cleaned up this transaction while we slept, we're
+ * done (maybe it's a new transaction, but it fell at the same
+ * address).
+ */
+ if (journal->j_checkpoint_transactions != transaction ||
+ transaction->t_tid != this_tid)
+ goto out;
+
+ /* checkpoint all of the transaction's buffers */
+ while (transaction->t_checkpoint_list) {
+ jh = transaction->t_checkpoint_list;
+ bh = jh2bh(jh);
+
+ if (jh->b_transaction != NULL) {
+ transaction_t *t = jh->b_transaction;
+ tid_t tid = t->t_tid;
+
+ transaction->t_chp_stats.cs_forced_to_close++;
+ spin_unlock(&journal->j_list_lock);
+ if (unlikely(journal->j_flags & JBD2_UNMOUNT))
+ /*
+ * The journal thread is dead; so
+ * starting and waiting for a commit
+ * to finish will cause us to wait for
+ * a _very_ long time.
+ */
+ printk(KERN_ERR
+ "JBD2: %s: Waiting for Godot: block %llu\n",
+ journal->j_devname, (unsigned long long) bh->b_blocknr);
+
+ if (batch_count)
+ __flush_batch(journal, &batch_count);
+ jbd2_log_start_commit(journal, tid);
+ /*
+ * jbd2_journal_commit_transaction() may want
+ * to take the checkpoint_mutex if JBD2_FLUSHED
+ * is set, jbd2_update_log_tail() called by
+ * jbd2_journal_commit_transaction() may also take
+ * checkpoint_mutex. So we need to temporarily
+ * drop it.
+ */
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ jbd2_log_wait_commit(journal, tid);
+ mutex_lock_io(&journal->j_checkpoint_mutex);
+ spin_lock(&journal->j_list_lock);
+ goto restart;
+ }
+ if (!trylock_buffer(bh)) {
+ /*
+ * The buffer is locked, it may be writing back, or
+ * flushing out in the last couple of cycles, or
+ * re-adding into a new transaction, need to check
+ * it again until it's unlocked.
+ */
+ get_bh(bh);
+ spin_unlock(&journal->j_list_lock);
+ wait_on_buffer(bh);
+ /* the journal_head may have gone by now */
+ BUFFER_TRACE(bh, "brelse");
+ __brelse(bh);
+ goto retry;
+ } else if (!buffer_dirty(bh)) {
+ unlock_buffer(bh);
+ BUFFER_TRACE(bh, "remove from checkpoint");
+ /*
+ * If the transaction was released or the checkpoint
+ * list was empty, we're done.
+ */
+ if (__jbd2_journal_remove_checkpoint(jh) ||
+ !transaction->t_checkpoint_list)
+ goto out;
+ } else {
+ unlock_buffer(bh);
+ /*
+ * We are about to write the buffer, it could be
+ * raced by some other transaction shrink or buffer
+ * re-log logic once we release the j_list_lock,
+ * leave it on the checkpoint list and check status
+ * again to make sure it's clean.
+ */
+ BUFFER_TRACE(bh, "queue");
+ get_bh(bh);
+ J_ASSERT_BH(bh, !buffer_jwrite(bh));
+ journal->j_chkpt_bhs[batch_count++] = bh;
+ transaction->t_chp_stats.cs_written++;
+ transaction->t_checkpoint_list = jh->b_cpnext;
+ }
+
+ if ((batch_count == JBD2_NR_BATCH) ||
+ need_resched() || spin_needbreak(&journal->j_list_lock) ||
+ jh2bh(transaction->t_checkpoint_list) == journal->j_chkpt_bhs[0])
+ goto unlock_and_flush;
+ }
+
+ if (batch_count) {
+ unlock_and_flush:
+ spin_unlock(&journal->j_list_lock);
+ retry:
+ if (batch_count)
+ __flush_batch(journal, &batch_count);
+ cond_resched();
+ spin_lock(&journal->j_list_lock);
+ goto restart;
+ }
+
+out:
+ spin_unlock(&journal->j_list_lock);
+ result = jbd2_cleanup_journal_tail(journal);
+
+ return (result < 0) ? result : 0;
+}
+
+/*
+ * Check the list of checkpoint transactions for the journal to see if
+ * we have already got rid of any since the last update of the log tail
+ * in the journal superblock. If so, we can instantly roll the
+ * superblock forward to remove those transactions from the log.
+ *
+ * Return <0 on error, 0 on success, 1 if there was nothing to clean up.
+ *
+ * Called with the journal lock held.
+ *
+ * This is the only part of the journaling code which really needs to be
+ * aware of transaction aborts. Checkpointing involves writing to the
+ * main filesystem area rather than to the journal, so it can proceed
+ * even in abort state, but we must not update the super block if
+ * checkpointing may have failed. Otherwise, we would lose some metadata
+ * buffers which should be written-back to the filesystem.
+ */
+
+int jbd2_cleanup_journal_tail(journal_t *journal)
+{
+ tid_t first_tid;
+ unsigned long blocknr;
+
+ if (is_journal_aborted(journal))
+ return -EIO;
+
+ if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr))
+ return 1;
+ J_ASSERT(blocknr != 0);
+
+ /*
+ * We need to make sure that any blocks that were recently written out
+ * --- perhaps by jbd2_log_do_checkpoint() --- are flushed out before
+ * we drop the transactions from the journal. It's unlikely this will
+ * be necessary, especially with an appropriately sized journal, but we
+ * need this to guarantee correctness. Fortunately
+ * jbd2_cleanup_journal_tail() doesn't get called all that often.
+ */
+ if (journal->j_flags & JBD2_BARRIER)
+ blkdev_issue_flush(journal->j_fs_dev);
+
+ return __jbd2_update_log_tail(journal, first_tid, blocknr);
+}
+
+
+/* Checkpoint list management */
+
+/*
+ * journal_shrink_one_cp_list
+ *
+ * Find all the written-back checkpoint buffers in the given list
+ * and try to release them. If the whole transaction is released, set
+ * the 'released' parameter. Return the number of released checkpointed
+ * buffers.
+ *
+ * Called with j_list_lock held.
+ */
+static unsigned long journal_shrink_one_cp_list(struct journal_head *jh,
+ enum jbd2_shrink_type type,
+ bool *released)
+{
+ struct journal_head *last_jh;
+ struct journal_head *next_jh = jh;
+ unsigned long nr_freed = 0;
+ int ret;
+
+ *released = false;
+ if (!jh)
+ return 0;
+
+ last_jh = jh->b_cpprev;
+ do {
+ jh = next_jh;
+ next_jh = jh->b_cpnext;
+
+ if (type == JBD2_SHRINK_DESTROY) {
+ ret = __jbd2_journal_remove_checkpoint(jh);
+ } else {
+ ret = jbd2_journal_try_remove_checkpoint(jh);
+ if (ret < 0) {
+ if (type == JBD2_SHRINK_BUSY_SKIP)
+ continue;
+ break;
+ }
+ }
+
+ nr_freed++;
+ if (ret) {
+ *released = true;
+ break;
+ }
+
+ if (need_resched())
+ break;
+ } while (jh != last_jh);
+
+ return nr_freed;
+}
+
+/*
+ * jbd2_journal_shrink_checkpoint_list
+ *
+ * Find 'nr_to_scan' written-back checkpoint buffers in the journal
+ * and try to release them. Return the number of released checkpointed
+ * buffers.
+ *
+ * Called with j_list_lock held.
+ */
+unsigned long jbd2_journal_shrink_checkpoint_list(journal_t *journal,
+ unsigned long *nr_to_scan)
+{
+ transaction_t *transaction, *last_transaction, *next_transaction;
+ bool __maybe_unused released;
+ tid_t first_tid = 0, last_tid = 0, next_tid = 0;
+ tid_t tid = 0;
+ unsigned long nr_freed = 0;
+ unsigned long freed;
+ bool first_set = false;
+
+again:
+ spin_lock(&journal->j_list_lock);
+ if (!journal->j_checkpoint_transactions) {
+ spin_unlock(&journal->j_list_lock);
+ goto out;
+ }
+
+ /*
+ * Get next shrink transaction, resume previous scan or start
+ * over again. If some others do checkpoint and drop transaction
+ * from the checkpoint list, we ignore saved j_shrink_transaction
+ * and start over unconditionally.
+ */
+ if (journal->j_shrink_transaction)
+ transaction = journal->j_shrink_transaction;
+ else
+ transaction = journal->j_checkpoint_transactions;
+
+ if (!first_set) {
+ first_tid = transaction->t_tid;
+ first_set = true;
+ }
+ last_transaction = journal->j_checkpoint_transactions->t_cpprev;
+ next_transaction = transaction;
+ last_tid = last_transaction->t_tid;
+ do {
+ transaction = next_transaction;
+ next_transaction = transaction->t_cpnext;
+ tid = transaction->t_tid;
+
+ freed = journal_shrink_one_cp_list(transaction->t_checkpoint_list,
+ JBD2_SHRINK_BUSY_SKIP, &released);
+ nr_freed += freed;
+ (*nr_to_scan) -= min(*nr_to_scan, freed);
+ if (*nr_to_scan == 0)
+ break;
+ if (need_resched() || spin_needbreak(&journal->j_list_lock))
+ break;
+ } while (transaction != last_transaction);
+
+ if (transaction != last_transaction) {
+ journal->j_shrink_transaction = next_transaction;
+ next_tid = next_transaction->t_tid;
+ } else {
+ journal->j_shrink_transaction = NULL;
+ next_tid = 0;
+ }
+
+ spin_unlock(&journal->j_list_lock);
+ cond_resched();
+
+ if (*nr_to_scan && journal->j_shrink_transaction)
+ goto again;
+out:
+ trace_jbd2_shrink_checkpoint_list(journal, first_tid, tid, last_tid,
+ nr_freed, next_tid);
+
+ return nr_freed;
+}
+
+/*
+ * journal_clean_checkpoint_list
+ *
+ * Find all the written-back checkpoint buffers in the journal and release them.
+ * If 'type' is JBD2_SHRINK_DESTROY, release all buffers unconditionally. If
+ * 'type' is JBD2_SHRINK_BUSY_STOP, will stop release buffers if encounters a
+ * busy buffer. To avoid wasting CPU cycles scanning the buffer list in some
+ * cases, don't pass JBD2_SHRINK_BUSY_SKIP 'type' for this function.
+ *
+ * Called with j_list_lock held.
+ */
+void __jbd2_journal_clean_checkpoint_list(journal_t *journal,
+ enum jbd2_shrink_type type)
+{
+ transaction_t *transaction, *last_transaction, *next_transaction;
+ bool released;
+
+ WARN_ON_ONCE(type == JBD2_SHRINK_BUSY_SKIP);
+
+ transaction = journal->j_checkpoint_transactions;
+ if (!transaction)
+ return;
+
+ last_transaction = transaction->t_cpprev;
+ next_transaction = transaction;
+ do {
+ transaction = next_transaction;
+ next_transaction = transaction->t_cpnext;
+ journal_shrink_one_cp_list(transaction->t_checkpoint_list,
+ type, &released);
+ /*
+ * This function only frees up some memory if possible so we
+ * dont have an obligation to finish processing. Bail out if
+ * preemption requested:
+ */
+ if (need_resched())
+ return;
+ /*
+ * Stop scanning if we couldn't free the transaction. This
+ * avoids pointless scanning of transactions which still
+ * weren't checkpointed.
+ */
+ if (!released)
+ return;
+ } while (transaction != last_transaction);
+}
+
+/*
+ * Remove buffers from all checkpoint lists as journal is aborted and we just
+ * need to free memory
+ */
+void jbd2_journal_destroy_checkpoint(journal_t *journal)
+{
+ /*
+ * We loop because __jbd2_journal_clean_checkpoint_list() may abort
+ * early due to a need of rescheduling.
+ */
+ while (1) {
+ spin_lock(&journal->j_list_lock);
+ if (!journal->j_checkpoint_transactions) {
+ spin_unlock(&journal->j_list_lock);
+ break;
+ }
+ __jbd2_journal_clean_checkpoint_list(journal, JBD2_SHRINK_DESTROY);
+ spin_unlock(&journal->j_list_lock);
+ cond_resched();
+ }
+}
+
+/*
+ * journal_remove_checkpoint: called after a buffer has been committed
+ * to disk (either by being write-back flushed to disk, or being
+ * committed to the log).
+ *
+ * We cannot safely clean a transaction out of the log until all of the
+ * buffer updates committed in that transaction have safely been stored
+ * elsewhere on disk. To achieve this, all of the buffers in a
+ * transaction need to be maintained on the transaction's checkpoint
+ * lists until they have been rewritten, at which point this function is
+ * called to remove the buffer from the existing transaction's
+ * checkpoint lists.
+ *
+ * The function returns 1 if it frees the transaction, 0 otherwise.
+ * The function can free jh and bh.
+ *
+ * This function is called with j_list_lock held.
+ */
+int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
+{
+ struct transaction_chp_stats_s *stats;
+ transaction_t *transaction;
+ journal_t *journal;
+
+ JBUFFER_TRACE(jh, "entry");
+
+ transaction = jh->b_cp_transaction;
+ if (!transaction) {
+ JBUFFER_TRACE(jh, "not on transaction");
+ return 0;
+ }
+ journal = transaction->t_journal;
+
+ JBUFFER_TRACE(jh, "removing from transaction");
+
+ __buffer_unlink(jh);
+ jh->b_cp_transaction = NULL;
+ percpu_counter_dec(&journal->j_checkpoint_jh_count);
+ jbd2_journal_put_journal_head(jh);
+
+ /* Is this transaction empty? */
+ if (transaction->t_checkpoint_list)
+ return 0;
+
+ /*
+ * There is one special case to worry about: if we have just pulled the
+ * buffer off a running or committing transaction's checkpoing list,
+ * then even if the checkpoint list is empty, the transaction obviously
+ * cannot be dropped!
+ *
+ * The locking here around t_state is a bit sleazy.
+ * See the comment at the end of jbd2_journal_commit_transaction().
+ */
+ if (transaction->t_state != T_FINISHED)
+ return 0;
+
+ /*
+ * OK, that was the last buffer for the transaction, we can now
+ * safely remove this transaction from the log.
+ */
+ stats = &transaction->t_chp_stats;
+ if (stats->cs_chp_time)
+ stats->cs_chp_time = jbd2_time_diff(stats->cs_chp_time,
+ jiffies);
+ trace_jbd2_checkpoint_stats(journal->j_fs_dev->bd_dev,
+ transaction->t_tid, stats);
+
+ __jbd2_journal_drop_transaction(journal, transaction);
+ jbd2_journal_free_transaction(transaction);
+ return 1;
+}
+
+/*
+ * Check the checkpoint buffer and try to remove it from the checkpoint
+ * list if it's clean. Returns -EBUSY if it is not clean, returns 1 if
+ * it frees the transaction, 0 otherwise.
+ *
+ * This function is called with j_list_lock held.
+ */
+int jbd2_journal_try_remove_checkpoint(struct journal_head *jh)
+{
+ struct buffer_head *bh = jh2bh(jh);
+
+ if (jh->b_transaction)
+ return -EBUSY;
+ if (!trylock_buffer(bh))
+ return -EBUSY;
+ if (buffer_dirty(bh)) {
+ unlock_buffer(bh);
+ return -EBUSY;
+ }
+ unlock_buffer(bh);
+
+ /*
+ * Buffer is clean and the IO has finished (we held the buffer
+ * lock) so the checkpoint is done. We can safely remove the
+ * buffer from this transaction.
+ */
+ JBUFFER_TRACE(jh, "remove from checkpoint list");
+ return __jbd2_journal_remove_checkpoint(jh);
+}
+
+/*
+ * journal_insert_checkpoint: put a committed buffer onto a checkpoint
+ * list so that we know when it is safe to clean the transaction out of
+ * the log.
+ *
+ * Called with the journal locked.
+ * Called with j_list_lock held.
+ */
+void __jbd2_journal_insert_checkpoint(struct journal_head *jh,
+ transaction_t *transaction)
+{
+ JBUFFER_TRACE(jh, "entry");
+ J_ASSERT_JH(jh, buffer_dirty(jh2bh(jh)) || buffer_jbddirty(jh2bh(jh)));
+ J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
+
+ /* Get reference for checkpointing transaction */
+ jbd2_journal_grab_journal_head(jh2bh(jh));
+ jh->b_cp_transaction = transaction;
+
+ if (!transaction->t_checkpoint_list) {
+ jh->b_cpnext = jh->b_cpprev = jh;
+ } else {
+ jh->b_cpnext = transaction->t_checkpoint_list;
+ jh->b_cpprev = transaction->t_checkpoint_list->b_cpprev;
+ jh->b_cpprev->b_cpnext = jh;
+ jh->b_cpnext->b_cpprev = jh;
+ }
+ transaction->t_checkpoint_list = jh;
+ percpu_counter_inc(&transaction->t_journal->j_checkpoint_jh_count);
+}
+
+/*
+ * We've finished with this transaction structure: adios...
+ *
+ * The transaction must have no links except for the checkpoint by this
+ * point.
+ *
+ * Called with the journal locked.
+ * Called with j_list_lock held.
+ */
+
+void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transaction)
+{
+ assert_spin_locked(&journal->j_list_lock);
+
+ journal->j_shrink_transaction = NULL;
+ if (transaction->t_cpnext) {
+ transaction->t_cpnext->t_cpprev = transaction->t_cpprev;
+ transaction->t_cpprev->t_cpnext = transaction->t_cpnext;
+ if (journal->j_checkpoint_transactions == transaction)
+ journal->j_checkpoint_transactions =
+ transaction->t_cpnext;
+ if (journal->j_checkpoint_transactions == transaction)
+ journal->j_checkpoint_transactions = NULL;
+ }
+
+ J_ASSERT(transaction->t_state == T_FINISHED);
+ J_ASSERT(transaction->t_buffers == NULL);
+ J_ASSERT(transaction->t_forget == NULL);
+ J_ASSERT(transaction->t_shadow_list == NULL);
+ J_ASSERT(transaction->t_checkpoint_list == NULL);
+ J_ASSERT(atomic_read(&transaction->t_updates) == 0);
+ J_ASSERT(journal->j_committing_transaction != transaction);
+ J_ASSERT(journal->j_running_transaction != transaction);
+
+ trace_jbd2_drop_transaction(journal, transaction);
+
+ jbd2_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid);
+}
new file mode 100644
@@ -0,0 +1,743 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * linux/fs/jbd2/revoke.c
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>, 2000
+ *
+ * Copyright 2000 Red Hat corp --- All Rights Reserved
+ *
+ * Journal revoke routines for the generic filesystem journaling code;
+ * part of the ext2fs journaling system.
+ *
+ * Revoke is the mechanism used to prevent old log records for deleted
+ * metadata from being replayed on top of newer data using the same
+ * blocks. The revoke mechanism is used in two separate places:
+ *
+ * + Commit: during commit we write the entire list of the current
+ * transaction's revoked blocks to the journal
+ *
+ * + Recovery: during recovery we record the transaction ID of all
+ * revoked blocks. If there are multiple revoke records in the log
+ * for a single block, only the last one counts, and if there is a log
+ * entry for a block beyond the last revoke, then that log entry still
+ * gets replayed.
+ *
+ * We can get interactions between revokes and new log data within a
+ * single transaction:
+ *
+ * Block is revoked and then journaled:
+ * The desired end result is the journaling of the new block, so we
+ * cancel the revoke before the transaction commits.
+ *
+ * Block is journaled and then revoked:
+ * The revoke must take precedence over the write of the block, so we
+ * need either to cancel the journal entry or to write the revoke
+ * later in the log than the log block. In this case, we choose the
+ * latter: journaling a block cancels any revoke record for that block
+ * in the current transaction, so any revoke for that block in the
+ * transaction must have happened after the block was journaled and so
+ * the revoke must take precedence.
+ *
+ * Block is revoked and then written as data:
+ * The data write is allowed to succeed, but the revoke is _not_
+ * cancelled. We still need to prevent old log records from
+ * overwriting the new data. We don't even need to clear the revoke
+ * bit here.
+ *
+ * We cache revoke status of a buffer in the current transaction in b_states
+ * bits. As the name says, revokevalid flag indicates that the cached revoke
+ * status of a buffer is valid and we can rely on the cached status.
+ *
+ * Revoke information on buffers is a tri-state value:
+ *
+ * RevokeValid clear: no cached revoke status, need to look it up
+ * RevokeValid set, Revoked clear:
+ * buffer has not been revoked, and cancel_revoke
+ * need do nothing.
+ * RevokeValid set, Revoked set:
+ * buffer has been revoked.
+ *
+ * Locking rules:
+ * We keep two hash tables of revoke records. One hashtable belongs to the
+ * running transaction (is pointed to by journal->j_revoke), the other one
+ * belongs to the committing transaction. Accesses to the second hash table
+ * happen only from the kjournald and no other thread touches this table. Also
+ * journal_switch_revoke_table() which switches which hashtable belongs to the
+ * running and which to the committing transaction is called only from
+ * kjournald. Therefore we need no locks when accessing the hashtable belonging
+ * to the committing transaction.
+ *
+ * All users operating on the hash table belonging to the running transaction
+ * have a handle to the transaction. Therefore they are safe from kjournald
+ * switching hash tables under them. For operations on the lists of entries in
+ * the hash table j_revoke_lock is used.
+ *
+ * Finally, also replay code uses the hash tables but at this moment no one else
+ * can touch them (filesystem isn't mounted yet) and hence no locking is
+ * needed.
+ */
+
+#ifndef __KERNEL__
+#include "jfs_user.h"
+#else
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/init.h>
+#include <linux/bio.h>
+#include <linux/log2.h>
+#include <linux/hash.h>
+#endif
+
+static struct kmem_cache *jbd2_revoke_record_cache;
+static struct kmem_cache *jbd2_revoke_table_cache;
+
+/* Each revoke record represents one single revoked block. During
+ journal replay, this involves recording the transaction ID of the
+ last transaction to revoke this block. */
+
+struct jbd2_revoke_record_s
+{
+ struct list_head hash;
+ tid_t sequence; /* Used for recovery only */
+ unsigned long long blocknr;
+};
+
+
+/* The revoke table is just a simple hash table of revoke records. */
+struct jbd2_revoke_table_s
+{
+ /* It is conceivable that we might want a larger hash table
+ * for recovery. Must be a power of two. */
+ int hash_size;
+ int hash_shift;
+ struct list_head *hash_table;
+};
+
+
+#ifdef __KERNEL__
+static void write_one_revoke_record(transaction_t *,
+ struct list_head *,
+ struct buffer_head **, int *,
+ struct jbd2_revoke_record_s *);
+static void flush_descriptor(journal_t *, struct buffer_head *, int);
+#endif
+
+/* Utility functions to maintain the revoke table */
+
+static inline int hash(journal_t *journal, unsigned long long block)
+{
+ return hash_64(block, journal->j_revoke->hash_shift);
+}
+
+static int insert_revoke_hash(journal_t *journal, unsigned long long blocknr,
+ tid_t seq)
+{
+ struct list_head *hash_list;
+ struct jbd2_revoke_record_s *record;
+ gfp_t gfp_mask = GFP_NOFS;
+
+ if (journal_oom_retry)
+ gfp_mask |= __GFP_NOFAIL;
+ record = kmem_cache_alloc(jbd2_revoke_record_cache, gfp_mask);
+ if (!record)
+ return -ENOMEM;
+
+ record->sequence = seq;
+ record->blocknr = blocknr;
+ hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)];
+ spin_lock(&journal->j_revoke_lock);
+ list_add(&record->hash, hash_list);
+ spin_unlock(&journal->j_revoke_lock);
+ return 0;
+}
+
+/* Find a revoke record in the journal's hash table. */
+
+static struct jbd2_revoke_record_s *find_revoke_record(journal_t *journal,
+ unsigned long long blocknr)
+{
+ struct list_head *hash_list;
+ struct jbd2_revoke_record_s *record;
+
+ hash_list = &journal->j_revoke->hash_table[hash(journal, blocknr)];
+
+ spin_lock(&journal->j_revoke_lock);
+ record = (struct jbd2_revoke_record_s *) hash_list->next;
+ while (&(record->hash) != hash_list) {
+ if (record->blocknr == blocknr) {
+ spin_unlock(&journal->j_revoke_lock);
+ return record;
+ }
+ record = (struct jbd2_revoke_record_s *) record->hash.next;
+ }
+ spin_unlock(&journal->j_revoke_lock);
+ return NULL;
+}
+
+void jbd2_journal_destroy_revoke_record_cache(void)
+{
+ kmem_cache_destroy(jbd2_revoke_record_cache);
+ jbd2_revoke_record_cache = NULL;
+}
+
+void jbd2_journal_destroy_revoke_table_cache(void)
+{
+ kmem_cache_destroy(jbd2_revoke_table_cache);
+ jbd2_revoke_table_cache = NULL;
+}
+
+int __init jbd2_journal_init_revoke_record_cache(void)
+{
+ J_ASSERT(!jbd2_revoke_record_cache);
+ jbd2_revoke_record_cache = KMEM_CACHE(jbd2_revoke_record_s,
+ SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY);
+
+ if (!jbd2_revoke_record_cache) {
+ pr_emerg("JBD2: failed to create revoke_record cache\n");
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+int __init jbd2_journal_init_revoke_table_cache(void)
+{
+ J_ASSERT(!jbd2_revoke_table_cache);
+ jbd2_revoke_table_cache = KMEM_CACHE(jbd2_revoke_table_s,
+ SLAB_TEMPORARY);
+ if (!jbd2_revoke_table_cache) {
+ pr_emerg("JBD2: failed to create revoke_table cache\n");
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+struct jbd2_revoke_table_s *jbd2_journal_init_revoke_table(int hash_size)
+{
+ int shift = 0;
+ int tmp = hash_size;
+ struct jbd2_revoke_table_s *table;
+
+ table = kmem_cache_alloc(jbd2_revoke_table_cache, GFP_KERNEL);
+ if (!table)
+ goto out;
+
+ while((tmp >>= 1UL) != 0UL)
+ shift++;
+
+ table->hash_size = hash_size;
+ table->hash_shift = shift;
+ table->hash_table =
+ kvmalloc_array(hash_size, sizeof(struct list_head), GFP_KERNEL);
+ if (!table->hash_table) {
+ kmem_cache_free(jbd2_revoke_table_cache, table);
+ table = NULL;
+ goto out;
+ }
+
+ for (tmp = 0; tmp < hash_size; tmp++)
+ INIT_LIST_HEAD(&table->hash_table[tmp]);
+
+out:
+ return table;
+}
+
+void jbd2_journal_destroy_revoke_table(struct jbd2_revoke_table_s *table)
+{
+ int i;
+ struct list_head *hash_list;
+
+ for (i = 0; i < table->hash_size; i++) {
+ hash_list = &table->hash_table[i];
+ J_ASSERT(list_empty(hash_list));
+ }
+
+ kvfree(table->hash_table);
+ kmem_cache_free(jbd2_revoke_table_cache, table);
+}
+
+/* Initialise the revoke table for a given journal to a given size. */
+int jbd2_journal_init_revoke(journal_t *journal, int hash_size)
+{
+ J_ASSERT(journal->j_revoke_table[0] == NULL);
+ J_ASSERT(is_power_of_2(hash_size));
+
+ journal->j_revoke_table[0] = jbd2_journal_init_revoke_table(hash_size);
+ if (!journal->j_revoke_table[0])
+ goto fail0;
+
+ journal->j_revoke_table[1] = jbd2_journal_init_revoke_table(hash_size);
+ if (!journal->j_revoke_table[1])
+ goto fail1;
+
+ journal->j_revoke = journal->j_revoke_table[1];
+
+ spin_lock_init(&journal->j_revoke_lock);
+
+ return 0;
+
+fail1:
+ jbd2_journal_destroy_revoke_table(journal->j_revoke_table[0]);
+ journal->j_revoke_table[0] = NULL;
+fail0:
+ return -ENOMEM;
+}
+
+/* Destroy a journal's revoke table. The table must already be empty! */
+void jbd2_journal_destroy_revoke(journal_t *journal)
+{
+ journal->j_revoke = NULL;
+ if (journal->j_revoke_table[0])
+ jbd2_journal_destroy_revoke_table(journal->j_revoke_table[0]);
+ if (journal->j_revoke_table[1])
+ jbd2_journal_destroy_revoke_table(journal->j_revoke_table[1]);
+}
+
+
+#ifdef __KERNEL__
+
+/*
+ * jbd2_journal_revoke: revoke a given buffer_head from the journal. This
+ * prevents the block from being replayed during recovery if we take a
+ * crash after this current transaction commits. Any subsequent
+ * metadata writes of the buffer in this transaction cancel the
+ * revoke.
+ *
+ * Note that this call may block --- it is up to the caller to make
+ * sure that there are no further calls to journal_write_metadata
+ * before the revoke is complete. In ext3, this implies calling the
+ * revoke before clearing the block bitmap when we are deleting
+ * metadata.
+ *
+ * Revoke performs a jbd2_journal_forget on any buffer_head passed in as a
+ * parameter, but does _not_ forget the buffer_head if the bh was only
+ * found implicitly.
+ *
+ * bh_in may not be a journalled buffer - it may have come off
+ * the hash tables without an attached journal_head.
+ *
+ * If bh_in is non-zero, jbd2_journal_revoke() will decrement its b_count
+ * by one.
+ */
+
+int jbd2_journal_revoke(handle_t *handle, unsigned long long blocknr,
+ struct buffer_head *bh_in)
+{
+ struct buffer_head *bh = NULL;
+ journal_t *journal;
+ struct block_device *bdev;
+ int err;
+
+ might_sleep();
+ if (bh_in)
+ BUFFER_TRACE(bh_in, "enter");
+
+ journal = handle->h_transaction->t_journal;
+ if (!jbd2_journal_set_features(journal, 0, 0, JBD2_FEATURE_INCOMPAT_REVOKE)){
+ J_ASSERT (!"Cannot set revoke feature!");
+ return -EINVAL;
+ }
+
+ bdev = journal->j_fs_dev;
+ bh = bh_in;
+
+ if (!bh) {
+ bh = __find_get_block_nonatomic(bdev, blocknr,
+ journal->j_blocksize);
+ if (bh)
+ BUFFER_TRACE(bh, "found on hash");
+ }
+#ifdef JBD2_EXPENSIVE_CHECKING
+ else {
+ struct buffer_head *bh2;
+
+ /* If there is a different buffer_head lying around in
+ * memory anywhere... */
+ bh2 = __find_get_block_nonatomic(bdev, blocknr,
+ journal->j_blocksize);
+ if (bh2) {
+ /* ... and it has RevokeValid status... */
+ if (bh2 != bh && buffer_revokevalid(bh2))
+ /* ...then it better be revoked too,
+ * since it's illegal to create a revoke
+ * record against a buffer_head which is
+ * not marked revoked --- that would
+ * risk missing a subsequent revoke
+ * cancel. */
+ J_ASSERT_BH(bh2, buffer_revoked(bh2));
+ put_bh(bh2);
+ }
+ }
+#endif
+
+ if (WARN_ON_ONCE(handle->h_revoke_credits <= 0)) {
+ if (!bh_in)
+ brelse(bh);
+ return -EIO;
+ }
+ /* We really ought not ever to revoke twice in a row without
+ first having the revoke cancelled: it's illegal to free a
+ block twice without allocating it in between! */
+ if (bh) {
+ if (!J_EXPECT_BH(bh, !buffer_revoked(bh),
+ "inconsistent data on disk")) {
+ if (!bh_in)
+ brelse(bh);
+ return -EIO;
+ }
+ set_buffer_revoked(bh);
+ set_buffer_revokevalid(bh);
+ if (bh_in) {
+ BUFFER_TRACE(bh_in, "call jbd2_journal_forget");
+ jbd2_journal_forget(handle, bh_in);
+ } else {
+ BUFFER_TRACE(bh, "call brelse");
+ __brelse(bh);
+ }
+ }
+ handle->h_revoke_credits--;
+
+ jbd2_debug(2, "insert revoke for block %llu, bh_in=%p\n",blocknr, bh_in);
+ err = insert_revoke_hash(journal, blocknr,
+ handle->h_transaction->t_tid);
+ BUFFER_TRACE(bh_in, "exit");
+ return err;
+}
+
+/*
+ * Cancel an outstanding revoke. For use only internally by the
+ * journaling code (called from jbd2_journal_get_write_access).
+ *
+ * We trust buffer_revoked() on the buffer if the buffer is already
+ * being journaled: if there is no revoke pending on the buffer, then we
+ * don't do anything here.
+ *
+ * This would break if it were possible for a buffer to be revoked and
+ * discarded, and then reallocated within the same transaction. In such
+ * a case we would have lost the revoked bit, but when we arrived here
+ * the second time we would still have a pending revoke to cancel. So,
+ * do not trust the Revoked bit on buffers unless RevokeValid is also
+ * set.
+ */
+void jbd2_journal_cancel_revoke(handle_t *handle, struct journal_head *jh)
+{
+ struct jbd2_revoke_record_s *record;
+ journal_t *journal = handle->h_transaction->t_journal;
+ int need_cancel;
+ struct buffer_head *bh = jh2bh(jh);
+
+ jbd2_debug(4, "journal_head %p, cancelling revoke\n", jh);
+
+ /* Is the existing Revoke bit valid? If so, we trust it, and
+ * only perform the full cancel if the revoke bit is set. If
+ * not, we can't trust the revoke bit, and we need to do the
+ * full search for a revoke record. */
+ if (test_set_buffer_revokevalid(bh)) {
+ need_cancel = test_clear_buffer_revoked(bh);
+ } else {
+ need_cancel = 1;
+ clear_buffer_revoked(bh);
+ }
+
+ if (need_cancel) {
+ record = find_revoke_record(journal, bh->b_blocknr);
+ if (record) {
+ jbd2_debug(4, "cancelled existing revoke on "
+ "blocknr %llu\n", (unsigned long long)bh->b_blocknr);
+ spin_lock(&journal->j_revoke_lock);
+ list_del(&record->hash);
+ spin_unlock(&journal->j_revoke_lock);
+ kmem_cache_free(jbd2_revoke_record_cache, record);
+ }
+ }
+
+#ifdef JBD2_EXPENSIVE_CHECKING
+ /* There better not be one left behind by now! */
+ record = find_revoke_record(journal, bh->b_blocknr);
+ J_ASSERT_JH(jh, record == NULL);
+#endif
+
+ /* Finally, have we just cleared revoke on an unhashed
+ * buffer_head? If so, we'd better make sure we clear the
+ * revoked status on any hashed alias too, otherwise the revoke
+ * state machine will get very upset later on. */
+ if (need_cancel) {
+ struct buffer_head *bh2;
+ bh2 = __find_get_block_nonatomic(bh->b_bdev, bh->b_blocknr,
+ bh->b_size);
+ if (bh2) {
+ if (bh2 != bh)
+ clear_buffer_revoked(bh2);
+ __brelse(bh2);
+ }
+ }
+}
+
+/*
+ * jbd2_clear_buffer_revoked_flags clears revoked flag of buffers in
+ * revoke table to reflect there is no revoked buffers in the next
+ * transaction which is going to be started.
+ */
+void jbd2_clear_buffer_revoked_flags(journal_t *journal)
+{
+ struct jbd2_revoke_table_s *revoke = journal->j_revoke;
+ int i = 0;
+
+ for (i = 0; i < revoke->hash_size; i++) {
+ struct list_head *hash_list;
+ struct list_head *list_entry;
+ hash_list = &revoke->hash_table[i];
+
+ list_for_each(list_entry, hash_list) {
+ struct jbd2_revoke_record_s *record;
+ struct buffer_head *bh;
+ record = (struct jbd2_revoke_record_s *)list_entry;
+ bh = __find_get_block_nonatomic(journal->j_fs_dev,
+ record->blocknr,
+ journal->j_blocksize);
+ if (bh) {
+ clear_buffer_revoked(bh);
+ __brelse(bh);
+ }
+ }
+ }
+}
+
+/* jbd2_journal_switch_revoke_table table select j_revoke for next
+ * transaction we do not want to suspend any processing until all
+ * revokes are written -bzzz
+ */
+void jbd2_journal_switch_revoke_table(journal_t *journal)
+{
+ int i;
+
+ if (journal->j_revoke == journal->j_revoke_table[0])
+ journal->j_revoke = journal->j_revoke_table[1];
+ else
+ journal->j_revoke = journal->j_revoke_table[0];
+
+ for (i = 0; i < journal->j_revoke->hash_size; i++)
+ INIT_LIST_HEAD(&journal->j_revoke->hash_table[i]);
+}
+
+/*
+ * Write revoke records to the journal for all entries in the current
+ * revoke hash, deleting the entries as we go.
+ */
+void jbd2_journal_write_revoke_records(transaction_t *transaction,
+ struct list_head *log_bufs)
+{
+ journal_t *journal = transaction->t_journal;
+ struct buffer_head *descriptor;
+ struct jbd2_revoke_record_s *record;
+ struct jbd2_revoke_table_s *revoke;
+ struct list_head *hash_list;
+ int i, offset, count;
+
+ descriptor = NULL;
+ offset = 0;
+ count = 0;
+
+ /* select revoke table for committing transaction */
+ revoke = journal->j_revoke == journal->j_revoke_table[0] ?
+ journal->j_revoke_table[1] : journal->j_revoke_table[0];
+
+ for (i = 0; i < revoke->hash_size; i++) {
+ hash_list = &revoke->hash_table[i];
+
+ while (!list_empty(hash_list)) {
+ record = (struct jbd2_revoke_record_s *)
+ hash_list->next;
+ write_one_revoke_record(transaction, log_bufs,
+ &descriptor, &offset, record);
+ count++;
+ list_del(&record->hash);
+ kmem_cache_free(jbd2_revoke_record_cache, record);
+ }
+ }
+ if (descriptor)
+ flush_descriptor(journal, descriptor, offset);
+ jbd2_debug(1, "Wrote %d revoke records\n", count);
+}
+
+/*
+ * Write out one revoke record. We need to create a new descriptor
+ * block if the old one is full or if we have not already created one.
+ */
+
+static void write_one_revoke_record(transaction_t *transaction,
+ struct list_head *log_bufs,
+ struct buffer_head **descriptorp,
+ int *offsetp,
+ struct jbd2_revoke_record_s *record)
+{
+ journal_t *journal = transaction->t_journal;
+ int csum_size = 0;
+ struct buffer_head *descriptor;
+ int sz, offset;
+
+ /* If we are already aborting, this all becomes a noop. We
+ still need to go round the loop in
+ jbd2_journal_write_revoke_records in order to free all of the
+ revoke records: only the IO to the journal is omitted. */
+ if (is_journal_aborted(journal))
+ return;
+
+ descriptor = *descriptorp;
+ offset = *offsetp;
+
+ /* Do we need to leave space at the end for a checksum? */
+ if (jbd2_journal_has_csum_v2or3(journal))
+ csum_size = sizeof(struct jbd2_journal_block_tail);
+
+ if (jbd2_has_feature_64bit(journal))
+ sz = 8;
+ else
+ sz = 4;
+
+ /* Make sure we have a descriptor with space left for the record */
+ if (descriptor) {
+ if (offset + sz > journal->j_blocksize - csum_size) {
+ flush_descriptor(journal, descriptor, offset);
+ descriptor = NULL;
+ }
+ }
+
+ if (!descriptor) {
+ descriptor = jbd2_journal_get_descriptor_buffer(transaction,
+ JBD2_REVOKE_BLOCK);
+ if (!descriptor)
+ return;
+
+ /* Record it so that we can wait for IO completion later */
+ BUFFER_TRACE(descriptor, "file in log_bufs");
+ jbd2_file_log_bh(log_bufs, descriptor);
+
+ offset = sizeof(jbd2_journal_revoke_header_t);
+ *descriptorp = descriptor;
+ }
+
+ if (jbd2_has_feature_64bit(journal))
+ * ((__be64 *)(&descriptor->b_data[offset])) =
+ cpu_to_be64(record->blocknr);
+ else
+ * ((__be32 *)(&descriptor->b_data[offset])) =
+ cpu_to_be32(record->blocknr);
+ offset += sz;
+
+ *offsetp = offset;
+}
+
+/*
+ * Flush a revoke descriptor out to the journal. If we are aborting,
+ * this is a noop; otherwise we are generating a buffer which needs to
+ * be waited for during commit, so it has to go onto the appropriate
+ * journal buffer list.
+ */
+
+static void flush_descriptor(journal_t *journal,
+ struct buffer_head *descriptor,
+ int offset)
+{
+ jbd2_journal_revoke_header_t *header;
+
+ if (is_journal_aborted(journal))
+ return;
+
+ header = (jbd2_journal_revoke_header_t *)descriptor->b_data;
+ header->r_count = cpu_to_be32(offset);
+ jbd2_descriptor_block_csum_set(journal, descriptor);
+
+ set_buffer_jwrite(descriptor);
+ BUFFER_TRACE(descriptor, "write");
+ set_buffer_dirty(descriptor);
+ write_dirty_buffer(descriptor, JBD2_JOURNAL_REQ_FLAGS);
+}
+#endif
+
+/*
+ * Revoke support for recovery.
+ *
+ * Recovery needs to be able to:
+ *
+ * record all revoke records, including the tid of the latest instance
+ * of each revoke in the journal
+ *
+ * check whether a given block in a given transaction should be replayed
+ * (ie. has not been revoked by a revoke record in that or a subsequent
+ * transaction)
+ *
+ * empty the revoke table after recovery.
+ */
+
+/*
+ * First, setting revoke records. We create a new revoke record for
+ * every block ever revoked in the log as we scan it for recovery, and
+ * we update the existing records if we find multiple revokes for a
+ * single block.
+ */
+
+int jbd2_journal_set_revoke(journal_t *journal,
+ unsigned long long blocknr,
+ tid_t sequence)
+{
+ struct jbd2_revoke_record_s *record;
+
+ record = find_revoke_record(journal, blocknr);
+ if (record) {
+ /* If we have multiple occurrences, only record the
+ * latest sequence number in the hashed record */
+ if (tid_gt(sequence, record->sequence))
+ record->sequence = sequence;
+ return 0;
+ }
+ return insert_revoke_hash(journal, blocknr, sequence);
+}
+
+/*
+ * Test revoke records. For a given block referenced in the log, has
+ * that block been revoked? A revoke record with a given transaction
+ * sequence number revokes all blocks in that transaction and earlier
+ * ones, but later transactions still need replayed.
+ */
+
+int jbd2_journal_test_revoke(journal_t *journal,
+ unsigned long long blocknr,
+ tid_t sequence)
+{
+ struct jbd2_revoke_record_s *record;
+
+ record = find_revoke_record(journal, blocknr);
+ if (!record)
+ return 0;
+ if (tid_gt(sequence, record->sequence))
+ return 0;
+ return 1;
+}
+
+/*
+ * Finally, once recovery is over, we need to clear the revoke table so
+ * that it can be reused by the running filesystem.
+ */
+
+void jbd2_journal_clear_revoke(journal_t *journal)
+{
+ int i;
+ struct list_head *hash_list;
+ struct jbd2_revoke_record_s *record;
+ struct jbd2_revoke_table_s *revoke;
+
+ revoke = journal->j_revoke;
+
+ for (i = 0; i < revoke->hash_size; i++) {
+ hash_list = &revoke->hash_table[i];
+ while (!list_empty(hash_list)) {
+ record = (struct jbd2_revoke_record_s*) hash_list->next;
+ list_del(&record->hash);
+ kmem_cache_free(jbd2_revoke_record_cache, record);
+ }
+ }
+}