6 files changed, 343 insertions, 270 deletions

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index d49d202903fb..c78841ee81cf 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -88,14 +88,13 @@ static inline void __buffer_relink_io(struct journal_head *jh)
  * whole transaction.
  *
  * Requires j_list_lock
- * Called under jbd_lock_bh_state(jh2bh(jh)), and drops it
  */
 static int __try_to_free_cp_buf(struct journal_head *jh)
 {
         int ret = 0;
         struct buffer_head *bh = jh2bh(jh);
 
-        if (jh->b_jlist == BJ_None && !buffer_locked(bh) &&
+        if (jh->b_transaction == NULL && !buffer_locked(bh) &&
             !buffer_dirty(bh) && !buffer_write_io_error(bh)) {
                 /*
                  * Get our reference so that bh cannot be freed before
@@ -104,11 +103,8 @@ static int __try_to_free_cp_buf(struct journal_head *jh)
                 get_bh(bh);
                 JBUFFER_TRACE(jh, "remove from checkpoint list");
                 ret = __jbd2_journal_remove_checkpoint(jh) + 1;
-                jbd_unlock_bh_state(bh);
                 BUFFER_TRACE(bh, "release");
                 __brelse(bh);
-        } else {
-                jbd_unlock_bh_state(bh);
         }
         return ret;
 }
@@ -180,21 +176,6 @@ void __jbd2_log_wait_for_space(journal_t *journal)
 }
 
 /*
- * We were unable to perform jbd_trylock_bh_state() inside j_list_lock.
- * The caller must restart a list walk.  Wait for someone else to run
- * jbd_unlock_bh_state().
- */
-static void jbd_sync_bh(journal_t *journal, struct buffer_head *bh)
-        __releases(journal->j_list_lock)
-{
-        get_bh(bh);
-        spin_unlock(&journal->j_list_lock);
-        jbd_lock_bh_state(bh);
-        jbd_unlock_bh_state(bh);
-        put_bh(bh);
-}
-
-/*
  * Clean up transaction's list of buffers submitted for io.
  * We wait for any pending IO to complete and remove any clean
  * buffers. Note that we take the buffers in the opposite ordering
@@ -222,15 +203,9 @@ restart:
         while (!released && transaction->t_checkpoint_io_list) {
                 jh = transaction->t_checkpoint_io_list;
                 bh = jh2bh(jh);
-                if (!jbd_trylock_bh_state(bh)) {
-                        jbd_sync_bh(journal, bh);
-                        spin_lock(&journal->j_list_lock);
-                        goto restart;
-                }
                 get_bh(bh);
                 if (buffer_locked(bh)) {
                         spin_unlock(&journal->j_list_lock);
-                        jbd_unlock_bh_state(bh);
                         wait_on_buffer(bh);
                         /* the journal_head may have gone by now */
                         BUFFER_TRACE(bh, "brelse");
@@ -246,7 +221,6 @@ restart:
                  * it has been written out and so we can drop it from the list
                  */
                 released = __jbd2_journal_remove_checkpoint(jh);
-                jbd_unlock_bh_state(bh);
                 __brelse(bh);
         }
 
@@ -266,7 +240,6 @@ __flush_batch(journal_t *journal, int *batch_count)
 
         for (i = 0; i < *batch_count; i++) {
                 struct buffer_head *bh = journal->j_chkpt_bhs[i];
-                clear_buffer_jwrite(bh);
                 BUFFER_TRACE(bh, "brelse");
                 __brelse(bh);
         }
@@ -281,7 +254,6 @@ __flush_batch(journal_t *journal, int *batch_count)
  * be written out.
  *
  * Called with j_list_lock held and drops it if 1 is returned
- * Called under jbd_lock_bh_state(jh2bh(jh)), and drops it
  */
 static int __process_buffer(journal_t *journal, struct journal_head *jh,
                             int *batch_count, transaction_t *transaction)
@@ -292,7 +264,6 @@ static int __process_buffer(journal_t *journal, struct journal_head *jh,
         if (buffer_locked(bh)) {
                 get_bh(bh);
                 spin_unlock(&journal->j_list_lock);
-                jbd_unlock_bh_state(bh);
                 wait_on_buffer(bh);
                 /* the journal_head may have gone by now */
                 BUFFER_TRACE(bh, "brelse");
@@ -304,7 +275,6 @@ static int __process_buffer(journal_t *journal, struct journal_head *jh,
 
                 transaction->t_chp_stats.cs_forced_to_close++;
                 spin_unlock(&journal->j_list_lock);
-                jbd_unlock_bh_state(bh);
                 if (unlikely(journal->j_flags & JBD2_UNMOUNT))
                         /*
                          * The journal thread is dead; so starting and
@@ -323,11 +293,9 @@ static int __process_buffer(journal_t *journal, struct journal_head *jh,
                 if (unlikely(buffer_write_io_error(bh)))
                         ret = -EIO;
                 get_bh(bh);
-                J_ASSERT_JH(jh, !buffer_jbddirty(bh));
                 BUFFER_TRACE(bh, "remove from checkpoint");
                 __jbd2_journal_remove_checkpoint(jh);
                 spin_unlock(&journal->j_list_lock);
-                jbd_unlock_bh_state(bh);
                 __brelse(bh);
         } else {
                 /*
@@ -340,10 +308,8 @@ static int __process_buffer(journal_t *journal, struct journal_head *jh,
                 BUFFER_TRACE(bh, "queue");
                 get_bh(bh);
                 J_ASSERT_BH(bh, !buffer_jwrite(bh));
-                set_buffer_jwrite(bh);
                 journal->j_chkpt_bhs[*batch_count] = bh;
                 __buffer_relink_io(jh);
-                jbd_unlock_bh_state(bh);
                 transaction->t_chp_stats.cs_written++;
                 (*batch_count)++;
                 if (*batch_count == JBD2_NR_BATCH) {
@@ -407,15 +373,7 @@ restart:
                 int retry = 0, err;
 
                 while (!retry && transaction->t_checkpoint_list) {
-                        struct buffer_head *bh;
-
                         jh = transaction->t_checkpoint_list;
-                        bh = jh2bh(jh);
-                        if (!jbd_trylock_bh_state(bh)) {
-                                jbd_sync_bh(journal, bh);
-                                retry = 1;
-                                break;
-                        }
                         retry = __process_buffer(journal, jh, &batch_count,
                                                  transaction);
                         if (retry < 0 && !result)
@@ -478,79 +436,28 @@ out:
 
 int jbd2_cleanup_journal_tail(journal_t *journal)
 {
-        transaction_t * transaction;
         tid_t           first_tid;
-        unsigned long   blocknr, freed;
+        unsigned long   blocknr;
 
         if (is_journal_aborted(journal))
                 return 1;
 
-        /* OK, work out the oldest transaction remaining in the log, and
-         * the log block it starts at.
-         *
-         * If the log is now empty, we need to work out which is the
-         * next transaction ID we will write, and where it will
-         * start. */
-
-        write_lock(&journal->j_state_lock);
-        spin_lock(&journal->j_list_lock);
-        transaction = journal->j_checkpoint_transactions;
-        if (transaction) {
-                first_tid = transaction->t_tid;
-                blocknr = transaction->t_log_start;
-        } else if ((transaction = journal->j_committing_transaction) != NULL) {
-                first_tid = transaction->t_tid;
-                blocknr = transaction->t_log_start;
-        } else if ((transaction = journal->j_running_transaction) != NULL) {
-                first_tid = transaction->t_tid;
-                blocknr = journal->j_head;
-        } else {
-                first_tid = journal->j_transaction_sequence;
-                blocknr = journal->j_head;
-        }
-        spin_unlock(&journal->j_list_lock);
-        J_ASSERT(blocknr != 0);
-
-        /* If the oldest pinned transaction is at the tail of the log
-           already then there's not much we can do right now. */
-        if (journal->j_tail_sequence == first_tid) {
-                write_unlock(&journal->j_state_lock);
+        if (!jbd2_journal_get_log_tail(journal, &first_tid, &blocknr))
                 return 1;
-        }
-
-        /* OK, update the superblock to recover the freed space.
-         * Physical blocks come first: have we wrapped beyond the end of
-         * the log?  */
-        freed = blocknr - journal->j_tail;
-        if (blocknr < journal->j_tail)
-                freed = freed + journal->j_last - journal->j_first;
-
-        trace_jbd2_cleanup_journal_tail(journal, first_tid, blocknr, freed);
-        jbd_debug(1,
-                  "Cleaning journal tail from %d to %d (offset %lu), "
-                  "freeing %lu\n",
-                  journal->j_tail_sequence, first_tid, blocknr, freed);
-
-        journal->j_free += freed;
-        journal->j_tail_sequence = first_tid;
-        journal->j_tail = blocknr;
-        write_unlock(&journal->j_state_lock);
+        J_ASSERT(blocknr != 0);
 
         /*
-         * If there is an external journal, we need to make sure that
-         * any data blocks that were recently written out --- perhaps
-         * by jbd2_log_do_checkpoint() --- are flushed out before we
-         * drop the transactions from the external journal.  It's
-         * unlikely this will be necessary, especially with a
-         * appropriately sized journal, but we need this to guarantee
-         * correctness.  Fortunately jbd2_cleanup_journal_tail()
-         * doesn't get called all that often.
+         * 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_fs_dev != journal->j_dev) &&
-            (journal->j_flags & JBD2_BARRIER))
+        if (journal->j_flags & JBD2_BARRIER)
                 blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
-        if (!(journal->j_flags & JBD2_ABORT))
-                jbd2_journal_update_superblock(journal, 1);
+
+        __jbd2_update_log_tail(journal, first_tid, blocknr);
         return 0;
 }
 
@@ -582,15 +489,12 @@ static int journal_clean_one_cp_list(struct journal_head *jh, int *released)
         do {
                 jh = next_jh;
                 next_jh = jh->b_cpnext;
-                /* Use trylock because of the ranking */
-                if (jbd_trylock_bh_state(jh2bh(jh))) {
-                        ret = __try_to_free_cp_buf(jh);
-                        if (ret) {
-                                freed++;
-                                if (ret == 2) {
-                                        *released = 1;
-                                        return freed;
-                                }
+                ret = __try_to_free_cp_buf(jh);
+                if (ret) {
+                        freed++;
+                        if (ret == 2) {
+                                *released = 1;
+                                return freed;
                         }
                 }
                 /*
@@ -673,9 +577,7 @@ out:
  * The function can free jh and bh.
  *
  * This function is called with j_list_lock held.
- * This function is called with jbd_lock_bh_state(jh2bh(jh))
  */
-
 int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
 {
         struct transaction_chp_stats_s *stats;
@@ -722,7 +624,7 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
                                     transaction->t_tid, stats);
 
         __jbd2_journal_drop_transaction(journal, transaction);
-        kfree(transaction);
+        jbd2_journal_free_transaction(transaction);
 
         /* Just in case anybody was waiting for more transactions to be
            checkpointed... */
@@ -797,5 +699,7 @@ void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transact
         J_ASSERT(journal->j_committing_transaction != transaction);
         J_ASSERT(journal->j_running_transaction != transaction);
 
+        trace_jbd2_drop_transaction(journal, transaction);
+
         jbd_debug(1, "Dropping transaction %d, all done\n", transaction->t_tid);
 }
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index c067a8cae63b..17f557f01cf0 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -331,6 +331,10 @@ void jbd2_journal_commit_transaction(journal_t *journal)
         struct buffer_head *cbh = NULL; /* For transactional checksums */
         __u32 crc32_sum = ~0;
         struct blk_plug plug;
+        /* Tail of the journal */
+        unsigned long first_block;
+        tid_t first_tid;
+        int update_tail;
 
         /*
          * First job: lock down the current transaction and wait for
@@ -340,7 +344,18 @@ void jbd2_journal_commit_transaction(journal_t *journal)
         /* Do we need to erase the effects of a prior jbd2_journal_flush? */
         if (journal->j_flags & JBD2_FLUSHED) {
                 jbd_debug(3, "super block updated\n");
-                jbd2_journal_update_superblock(journal, 1);
+                mutex_lock(&journal->j_checkpoint_mutex);
+                /*
+                 * We hold j_checkpoint_mutex so tail cannot change under us.
+                 * We don't need any special data guarantees for writing sb
+                 * since journal is empty and it is ok for write to be
+                 * flushed only with transaction commit.
+                 */
+                jbd2_journal_update_sb_log_tail(journal,
+                                                journal->j_tail_sequence,
+                                                journal->j_tail,
+                                                WRITE_SYNC);
+                mutex_unlock(&journal->j_checkpoint_mutex);
         } else {
                 jbd_debug(3, "superblock not updated\n");
         }
@@ -677,10 +692,30 @@ start_journal_io:
                 err = 0;
         }
 
+        /*
+         * Get current oldest transaction in the log before we issue flush
+         * to the filesystem device. After the flush we can be sure that
+         * blocks of all older transactions are checkpointed to persistent
+         * storage and we will be safe to update journal start in the
+         * superblock with the numbers we get here.
+         */
+        update_tail =
+                jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
+
         write_lock(&journal->j_state_lock);
+        if (update_tail) {
+                long freed = first_block - journal->j_tail;
+
+                if (first_block < journal->j_tail)
+                        freed += journal->j_last - journal->j_first;
+                /* Update tail only if we free significant amount of space */
+                if (freed < journal->j_maxlen / 4)
+                        update_tail = 0;
+        }
         J_ASSERT(commit_transaction->t_state == T_COMMIT);
         commit_transaction->t_state = T_COMMIT_DFLUSH;
         write_unlock(&journal->j_state_lock);
+
         /* 
          * If the journal is not located on the file system device,
          * then we must flush the file system device before we issue
@@ -831,6 +866,14 @@ wait_for_iobuf:
         if (err)
                 jbd2_journal_abort(journal, err);
 
+        /*
+         * Now disk caches for filesystem device are flushed so we are safe to
+         * erase checkpointed transactions from the log by updating journal
+         * superblock.
+         */
+        if (update_tail)
+                jbd2_update_log_tail(journal, first_tid, first_block);
+
         /* End of a transaction!  Finally, we can do checkpoint
            processing: any buffers committed as a result of this
            transaction can be removed from any checkpoint list it was on
@@ -1048,7 +1091,7 @@ restart_loop:
         jbd_debug(1, "JBD2: commit %d complete, head %d\n",
                   journal->j_commit_sequence, journal->j_tail_sequence);
         if (to_free)
-                kfree(commit_transaction);
+                jbd2_journal_free_transaction(commit_transaction);
 
         wake_up(&journal->j_wait_done_commit);
 }
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 839377e3d624..98ed6dbfe381 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -71,7 +71,6 @@ EXPORT_SYMBOL(jbd2_journal_revoke);
 
 EXPORT_SYMBOL(jbd2_journal_init_dev);
 EXPORT_SYMBOL(jbd2_journal_init_inode);
-EXPORT_SYMBOL(jbd2_journal_update_format);
 EXPORT_SYMBOL(jbd2_journal_check_used_features);
 EXPORT_SYMBOL(jbd2_journal_check_available_features);
 EXPORT_SYMBOL(jbd2_journal_set_features);
@@ -96,7 +95,6 @@ EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
 EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
 EXPORT_SYMBOL(jbd2_inode_cache);
 
-static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
 static void __journal_abort_soft (journal_t *journal, int errno);
 static int jbd2_journal_create_slab(size_t slab_size);
 
@@ -746,6 +744,98 @@ struct journal_head *jbd2_journal_get_descriptor_buffer(journal_t *journal)
         return jbd2_journal_add_journal_head(bh);
 }
 
+/*
+ * Return tid of the oldest transaction in the journal and block in the journal
+ * where the transaction starts.
+ *
+ * If the journal is now empty, return which will be the next transaction ID
+ * we will write and where will that transaction start.
+ *
+ * The return value is 0 if journal tail cannot be pushed any further, 1 if
+ * it can.
+ */
+int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
+                              unsigned long *block)
+{
+        transaction_t *transaction;
+        int ret;
+
+        read_lock(&journal->j_state_lock);
+        spin_lock(&journal->j_list_lock);
+        transaction = journal->j_checkpoint_transactions;
+        if (transaction) {
+                *tid = transaction->t_tid;
+                *block = transaction->t_log_start;
+        } else if ((transaction = journal->j_committing_transaction) != NULL) {
+                *tid = transaction->t_tid;
+                *block = transaction->t_log_start;
+        } else if ((transaction = journal->j_running_transaction) != NULL) {
+                *tid = transaction->t_tid;
+                *block = journal->j_head;
+        } else {
+                *tid = journal->j_transaction_sequence;
+                *block = journal->j_head;
+        }
+        ret = tid_gt(*tid, journal->j_tail_sequence);
+        spin_unlock(&journal->j_list_lock);
+        read_unlock(&journal->j_state_lock);
+
+        return ret;
+}
+
+/*
+ * Update information in journal structure and in on disk journal superblock
+ * about log tail. This function does not check whether information passed in
+ * really pushes log tail further. It's responsibility of the caller to make
+ * sure provided log tail information is valid (e.g. by holding
+ * j_checkpoint_mutex all the time between computing log tail and calling this
+ * function as is the case with jbd2_cleanup_journal_tail()).
+ *
+ * Requires j_checkpoint_mutex
+ */
+void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
+{
+        unsigned long freed;
+
+        BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
+
+        /*
+         * We cannot afford for write to remain in drive's caches since as
+         * soon as we update j_tail, next transaction can start reusing journal
+         * space and if we lose sb update during power failure we'd replay
+         * old transaction with possibly newly overwritten data.
+         */
+        jbd2_journal_update_sb_log_tail(journal, tid, block, WRITE_FUA);
+        write_lock(&journal->j_state_lock);
+        freed = block - journal->j_tail;
+        if (block < journal->j_tail)
+                freed += journal->j_last - journal->j_first;
+
+        trace_jbd2_update_log_tail(journal, tid, block, freed);
+        jbd_debug(1,
+                  "Cleaning journal tail from %d to %d (offset %lu), "
+                  "freeing %lu\n",
+                  journal->j_tail_sequence, tid, block, freed);
+
+        journal->j_free += freed;
+        journal->j_tail_sequence = tid;
+        journal->j_tail = block;
+        write_unlock(&journal->j_state_lock);
+}
+
+/*
+ * This is a variaon of __jbd2_update_log_tail which checks for validity of
+ * provided log tail and locks j_checkpoint_mutex. So it is safe against races
+ * with other threads updating log tail.
+ */
+void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
+{
+        mutex_lock(&journal->j_checkpoint_mutex);
+        if (tid_gt(tid, journal->j_tail_sequence))
+                __jbd2_update_log_tail(journal, tid, block);
+        mutex_unlock(&journal->j_checkpoint_mutex);
+}
+
 struct jbd2_stats_proc_session {
         journal_t *journal;
         struct transaction_stats_s *stats;
@@ -1114,40 +1204,45 @@ static int journal_reset(journal_t *journal)
 
         journal->j_max_transaction_buffers = journal->j_maxlen / 4;
 
-        /* Add the dynamic fields and write it to disk. */
-        jbd2_journal_update_superblock(journal, 1);
-        return jbd2_journal_start_thread(journal);
-}
-
-/**
- * void jbd2_journal_update_superblock() - Update journal sb on disk.
- * @journal: The journal to update.
- * @wait: Set to '0' if you don't want to wait for IO completion.
- *
- * Update a journal's dynamic superblock fields and write it to disk,
- * optionally waiting for the IO to complete.
- */
-void jbd2_journal_update_superblock(journal_t *journal, int wait)
-{
-        journal_superblock_t *sb = journal->j_superblock;
-        struct buffer_head *bh = journal->j_sb_buffer;
-
         /*
          * As a special case, if the on-disk copy is already marked as needing
-         * no recovery (s_start == 0) and there are no outstanding transactions
-         * in the filesystem, then we can safely defer the superblock update
-         * until the next commit by setting JBD2_FLUSHED.  This avoids
+         * no recovery (s_start == 0), then we can safely defer the superblock
+         * update until the next commit by setting JBD2_FLUSHED.  This avoids
          * attempting a write to a potential-readonly device.
          */
-        if (sb->s_start == 0 && journal->j_tail_sequence ==
-                                journal->j_transaction_sequence) {
+        if (sb->s_start == 0) {
                 jbd_debug(1, "JBD2: Skipping superblock update on recovered sb "
                         "(start %ld, seq %d, errno %d)\n",
                         journal->j_tail, journal->j_tail_sequence,
                         journal->j_errno);
-                goto out;
+                journal->j_flags |= JBD2_FLUSHED;
+        } else {
+                /* Lock here to make assertions happy... */
+                mutex_lock(&journal->j_checkpoint_mutex);
+                /*
+                 * Update log tail information. We use WRITE_FUA since new
+                 * transaction will start reusing journal space and so we
+                 * must make sure information about current log tail is on
+                 * disk before that.
+                 */
+                jbd2_journal_update_sb_log_tail(journal,
+                                                journal->j_tail_sequence,
+                                                journal->j_tail,
+                                                WRITE_FUA);
+                mutex_unlock(&journal->j_checkpoint_mutex);
         }
+        return jbd2_journal_start_thread(journal);
+}
 
+static void jbd2_write_superblock(journal_t *journal, int write_op)
+{
+        struct buffer_head *bh = journal->j_sb_buffer;
+        int ret;
+
+        trace_jbd2_write_superblock(journal, write_op);
+        if (!(journal->j_flags & JBD2_BARRIER))
+                write_op &= ~(REQ_FUA | REQ_FLUSH);
+        lock_buffer(bh);
         if (buffer_write_io_error(bh)) {
                 /*
                  * Oh, dear.  A previous attempt to write the journal
@@ -1163,48 +1258,106 @@ void jbd2_journal_update_superblock(journal_t *journal, int wait)
                 clear_buffer_write_io_error(bh);
                 set_buffer_uptodate(bh);
         }
+        get_bh(bh);
+        bh->b_end_io = end_buffer_write_sync;
+        ret = submit_bh(write_op, bh);
+        wait_on_buffer(bh);
+        if (buffer_write_io_error(bh)) {
+                clear_buffer_write_io_error(bh);
+                set_buffer_uptodate(bh);
+                ret = -EIO;
+        }
+        if (ret) {
+                printk(KERN_ERR "JBD2: Error %d detected when updating "
+                       "journal superblock for %s.\n", ret,
+                       journal->j_devname);
+        }
+}
+
+/**
+ * jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk.
+ * @journal: The journal to update.
+ * @tail_tid: TID of the new transaction at the tail of the log
+ * @tail_block: The first block of the transaction at the tail of the log
+ * @write_op: With which operation should we write the journal sb
+ *
+ * Update a journal's superblock information about log tail and write it to
+ * disk, waiting for the IO to complete.
+ */
+void jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
+                                     unsigned long tail_block, int write_op)
+{
+        journal_superblock_t *sb = journal->j_superblock;
+
+        BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
+        jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
+                  tail_block, tail_tid);
+
+        sb->s_sequence = cpu_to_be32(tail_tid);
+        sb->s_start    = cpu_to_be32(tail_block);
+
+        jbd2_write_superblock(journal, write_op);
+
+        /* Log is no longer empty */
+        write_lock(&journal->j_state_lock);
+        WARN_ON(!sb->s_sequence);
+        journal->j_flags &= ~JBD2_FLUSHED;
+        write_unlock(&journal->j_state_lock);
+}
+
+/**
+ * jbd2_mark_journal_empty() - Mark on disk journal as empty.
+ * @journal: The journal to update.
+ *
+ * Update a journal's dynamic superblock fields to show that journal is empty.
+ * Write updated superblock to disk waiting for IO to complete.
+ */
+static void jbd2_mark_journal_empty(journal_t *journal)
+{
+        journal_superblock_t *sb = journal->j_superblock;
 
+        BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
         read_lock(&journal->j_state_lock);
-        jbd_debug(1, "JBD2: updating superblock (start %ld, seq %d, errno %d)\n",
-                  journal->j_tail, journal->j_tail_sequence, journal->j_errno);
+        jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n",
+                  journal->j_tail_sequence);
 
         sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
-        sb->s_start    = cpu_to_be32(journal->j_tail);
-        sb->s_errno    = cpu_to_be32(journal->j_errno);
+        sb->s_start    = cpu_to_be32(0);
         read_unlock(&journal->j_state_lock);
 
-        BUFFER_TRACE(bh, "marking dirty");
-        mark_buffer_dirty(bh);
-        if (wait) {
-                sync_dirty_buffer(bh);
-                if (buffer_write_io_error(bh)) {
-                        printk(KERN_ERR "JBD2: I/O error detected "
-                               "when updating journal superblock for %s.\n",
-                               journal->j_devname);
-                        clear_buffer_write_io_error(bh);
-                        set_buffer_uptodate(bh);
-                }
-        } else
-                write_dirty_buffer(bh, WRITE);
-
-out:
-        /* If we have just flushed the log (by marking s_start==0), then
-         * any future commit will have to be careful to update the
-         * superblock again to re-record the true start of the log. */
+        jbd2_write_superblock(journal, WRITE_FUA);
 
+        /* Log is no longer empty */
         write_lock(&journal->j_state_lock);
-        if (sb->s_start)
-                journal->j_flags &= ~JBD2_FLUSHED;
-        else
-                journal->j_flags |= JBD2_FLUSHED;
+        journal->j_flags |= JBD2_FLUSHED;
         write_unlock(&journal->j_state_lock);
 }
 
+
+/**
+ * jbd2_journal_update_sb_errno() - Update error in the journal.
+ * @journal: The journal to update.
+ *
+ * Update a journal's errno.  Write updated superblock to disk waiting for IO
+ * to complete.
+ */
+static void jbd2_journal_update_sb_errno(journal_t *journal)
+{
+        journal_superblock_t *sb = journal->j_superblock;
+
+        read_lock(&journal->j_state_lock);
+        jbd_debug(1, "JBD2: updating superblock error (errno %d)\n",
+                  journal->j_errno);
+        sb->s_errno    = cpu_to_be32(journal->j_errno);
+        read_unlock(&journal->j_state_lock);
+
+        jbd2_write_superblock(journal, WRITE_SYNC);
+}
+
 /*
  * Read the superblock for a given journal, performing initial
  * validation of the format.
  */
-
 static int journal_get_superblock(journal_t *journal)
 {
         struct buffer_head *bh;
@@ -1398,14 +1551,11 @@ int jbd2_journal_destroy(journal_t *journal)
 
         if (journal->j_sb_buffer) {
                 if (!is_journal_aborted(journal)) {
-                        /* We can now mark the journal as empty. */
-                        journal->j_tail = 0;
-                        journal->j_tail_sequence =
-                                ++journal->j_transaction_sequence;
-                        jbd2_journal_update_superblock(journal, 1);
-                } else {
+                        mutex_lock(&journal->j_checkpoint_mutex);
+                        jbd2_mark_journal_empty(journal);
+                        mutex_unlock(&journal->j_checkpoint_mutex);
+                } else
                         err = -EIO;
-                }
                 brelse(journal->j_sb_buffer);
         }
 
@@ -1552,61 +1702,6 @@ void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
 EXPORT_SYMBOL(jbd2_journal_clear_features);
 
 /**
- * int jbd2_journal_update_format () - Update on-disk journal structure.
- * @journal: Journal to act on.
- *
- * Given an initialised but unloaded journal struct, poke about in the
- * on-disk structure to update it to the most recent supported version.
- */
-int jbd2_journal_update_format (journal_t *journal)
-{
-        journal_superblock_t *sb;
-        int err;
-
-        err = journal_get_superblock(journal);
-        if (err)
-                return err;
-
-        sb = journal->j_superblock;
-
-        switch (be32_to_cpu(sb->s_header.h_blocktype)) {
-        case JBD2_SUPERBLOCK_V2:
-                return 0;
-        case JBD2_SUPERBLOCK_V1:
-                return journal_convert_superblock_v1(journal, sb);
-        default:
-                break;
-        }
-        return -EINVAL;
-}
-
-static int journal_convert_superblock_v1(journal_t *journal,
-                                         journal_superblock_t *sb)
-{
-        int offset, blocksize;
-        struct buffer_head *bh;
-
-        printk(KERN_WARNING
-                "JBD2: Converting superblock from version 1 to 2.\n");
-
-        /* Pre-initialise new fields to zero */
-        offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb);
-        blocksize = be32_to_cpu(sb->s_blocksize);
-        memset(&sb->s_feature_compat, 0, blocksize-offset);
-
-        sb->s_nr_users = cpu_to_be32(1);
-        sb->s_header.h_blocktype = cpu_to_be32(JBD2_SUPERBLOCK_V2);
-        journal->j_format_version = 2;
-
-        bh = journal->j_sb_buffer;
-        BUFFER_TRACE(bh, "marking dirty");
-        mark_buffer_dirty(bh);
-        sync_dirty_buffer(bh);
-        return 0;
-}
-
-
-/**
  * int jbd2_journal_flush () - Flush journal
  * @journal: Journal to act on.
  *
@@ -1619,7 +1714,6 @@ int jbd2_journal_flush(journal_t *journal)
 {
         int err = 0;
         transaction_t *transaction = NULL;
-        unsigned long old_tail;
 
         write_lock(&journal->j_state_lock);
 
@@ -1654,6 +1748,7 @@ int jbd2_journal_flush(journal_t *journal)
         if (is_journal_aborted(journal))
                 return -EIO;
 
+        mutex_lock(&journal->j_checkpoint_mutex);
         jbd2_cleanup_journal_tail(journal);
 
         /* Finally, mark the journal as really needing no recovery.
@@ -1661,14 +1756,9 @@ int jbd2_journal_flush(journal_t *journal)
          * the magic code for a fully-recovered superblock.  Any future
          * commits of data to the journal will restore the current
          * s_start value. */
+        jbd2_mark_journal_empty(journal);
+        mutex_unlock(&journal->j_checkpoint_mutex);
         write_lock(&journal->j_state_lock);
-        old_tail = journal->j_tail;
-        journal->j_tail = 0;
-        write_unlock(&journal->j_state_lock);
-        jbd2_journal_update_superblock(journal, 1);
-        write_lock(&journal->j_state_lock);
-        journal->j_tail = old_tail;
-
         J_ASSERT(!journal->j_running_transaction);
         J_ASSERT(!journal->j_committing_transaction);
         J_ASSERT(!journal->j_checkpoint_transactions);
@@ -1708,8 +1798,12 @@ int jbd2_journal_wipe(journal_t *journal, int write)
                 write ? "Clearing" : "Ignoring");
 
         err = jbd2_journal_skip_recovery(journal);
-        if (write)
-                jbd2_journal_update_superblock(journal, 1);
+        if (write) {
+                /* Lock to make assertions happy... */
+                mutex_lock(&journal->j_checkpoint_mutex);
+                jbd2_mark_journal_empty(journal);
+                mutex_unlock(&journal->j_checkpoint_mutex);
+        }
 
  no_recovery:
         return err;
@@ -1759,7 +1853,7 @@ static void __journal_abort_soft (journal_t *journal, int errno)
         __jbd2_journal_abort_hard(journal);
 
         if (errno)
-                jbd2_journal_update_superblock(journal, 1);
+                jbd2_journal_update_sb_errno(journal);
 }
 
 /**
@@ -2017,7 +2111,7 @@ static struct kmem_cache *jbd2_journal_head_cache;
 static atomic_t nr_journal_heads = ATOMIC_INIT(0);
 #endif
 
-static int journal_init_jbd2_journal_head_cache(void)
+static int jbd2_journal_init_journal_head_cache(void)
 {
         int retval;
 
@@ -2035,7 +2129,7 @@ static int journal_init_jbd2_journal_head_cache(void)
         return retval;
 }
 
-static void jbd2_journal_destroy_jbd2_journal_head_cache(void)
+static void jbd2_journal_destroy_journal_head_cache(void)
 {
         if (jbd2_journal_head_cache) {
                 kmem_cache_destroy(jbd2_journal_head_cache);
@@ -2323,7 +2417,7 @@ static void __exit jbd2_remove_jbd_stats_proc_entry(void)
 
 struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
 
-static int __init journal_init_handle_cache(void)
+static int __init jbd2_journal_init_handle_cache(void)
 {
         jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
         if (jbd2_handle_cache == NULL) {
@@ -2358,17 +2452,20 @@ static int __init journal_init_caches(void)
 
         ret = jbd2_journal_init_revoke_caches();
         if (ret == 0)
-                ret = journal_init_jbd2_journal_head_cache();
+                ret = jbd2_journal_init_journal_head_cache();
+        if (ret == 0)
+                ret = jbd2_journal_init_handle_cache();
         if (ret == 0)
-                ret = journal_init_handle_cache();
+                ret = jbd2_journal_init_transaction_cache();
         return ret;
 }
 
 static void jbd2_journal_destroy_caches(void)
 {
         jbd2_journal_destroy_revoke_caches();
-        jbd2_journal_destroy_jbd2_journal_head_cache();
+        jbd2_journal_destroy_journal_head_cache();
         jbd2_journal_destroy_handle_cache();
+        jbd2_journal_destroy_transaction_cache();
         jbd2_journal_destroy_slabs();
 }
 
diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
index da6d7baf1390..c1a03354a22f 100644
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -21,6 +21,7 @@
 #include <linux/jbd2.h>
 #include <linux/errno.h>
 #include <linux/crc32.h>
+#include <linux/blkdev.h>
 #endif
 
 /*
@@ -265,7 +266,9 @@ int jbd2_journal_recover(journal_t *journal)
         err2 = sync_blockdev(journal->j_fs_dev);
         if (!err)
                 err = err2;
-
+        /* Make sure all replayed data is on permanent storage */
+        if (journal->j_flags & JBD2_BARRIER)
+                blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
         return err;
 }
 
diff --git a/fs/jbd2/revoke.c b/fs/jbd2/revoke.c
index 30b2867d6cc9..6973705d6a3d 100644
--- a/fs/jbd2/revoke.c
+++ b/fs/jbd2/revoke.c
@@ -208,17 +208,13 @@ int __init jbd2_journal_init_revoke_caches(void)
         J_ASSERT(!jbd2_revoke_record_cache);
         J_ASSERT(!jbd2_revoke_table_cache);
 
-        jbd2_revoke_record_cache = kmem_cache_create("jbd2_revoke_record",
-                                           sizeof(struct jbd2_revoke_record_s),
-                                           0,
-                                           SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY,
-                                           NULL);
+        jbd2_revoke_record_cache = KMEM_CACHE(jbd2_revoke_record_s,
+                                        SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY);
         if (!jbd2_revoke_record_cache)
                 goto record_cache_failure;
 
-        jbd2_revoke_table_cache = kmem_cache_create("jbd2_revoke_table",
-                                           sizeof(struct jbd2_revoke_table_s),
-                                           0, SLAB_TEMPORARY, NULL);
+        jbd2_revoke_table_cache = KMEM_CACHE(jbd2_revoke_table_s,
+                                             SLAB_TEMPORARY);
         if (!jbd2_revoke_table_cache)
                 goto table_cache_failure;
         return 0;
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index e5aba56e1fd5..ddcd3549c6c2 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -33,6 +33,35 @@
 static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh);
 static void __jbd2_journal_unfile_buffer(struct journal_head *jh);
 
+static struct kmem_cache *transaction_cache;
+int __init jbd2_journal_init_transaction_cache(void)
+{
+        J_ASSERT(!transaction_cache);
+        transaction_cache = kmem_cache_create("jbd2_transaction_s",
+                                        sizeof(transaction_t),
+                                        0,
+                                        SLAB_HWCACHE_ALIGN|SLAB_TEMPORARY,
+                                        NULL);
+        if (transaction_cache)
+                return 0;
+        return -ENOMEM;
+}
+
+void jbd2_journal_destroy_transaction_cache(void)
+{
+        if (transaction_cache) {
+                kmem_cache_destroy(transaction_cache);
+                transaction_cache = NULL;
+        }
+}
+
+void jbd2_journal_free_transaction(transaction_t *transaction)
+{
+        if (unlikely(ZERO_OR_NULL_PTR(transaction)))
+                return;
+        kmem_cache_free(transaction_cache, transaction);
+}
+
 /*
  * jbd2_get_transaction: obtain a new transaction_t object.
  *
@@ -133,7 +162,8 @@ static int start_this_handle(journal_t *journal, handle_t *handle,
 
 alloc_transaction:
         if (!journal->j_running_transaction) {
-                new_transaction = kzalloc(sizeof(*new_transaction), gfp_mask);
+                new_transaction = kmem_cache_alloc(transaction_cache,
+                                                   gfp_mask | __GFP_ZERO);
                 if (!new_transaction) {
                         /*
                          * If __GFP_FS is not present, then we may be
@@ -162,7 +192,7 @@ repeat:
         if (is_journal_aborted(journal) ||
             (journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) {
                 read_unlock(&journal->j_state_lock);
-                kfree(new_transaction);
+                jbd2_journal_free_transaction(new_transaction);
                 return -EROFS;
         }
 
@@ -284,7 +314,7 @@ repeat:
         read_unlock(&journal->j_state_lock);
 
         lock_map_acquire(&handle->h_lockdep_map);
-        kfree(new_transaction);
+        jbd2_journal_free_transaction(new_transaction);
         return 0;
 }
 
@@ -1549,9 +1579,9 @@ __blist_del_buffer(struct journal_head **list, struct journal_head *jh)
  * of these pointers, it could go bad.  Generally the caller needs to re-read
  * the pointer from the transaction_t.
  *
- * Called under j_list_lock.  The journal may not be locked.
+ * Called under j_list_lock.
  */
-void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh)
+static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh)
 {
         struct journal_head **list = NULL;
         transaction_t *transaction;
@@ -1646,10 +1676,8 @@ __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh)
         spin_lock(&journal->j_list_lock);
         if (jh->b_cp_transaction != NULL && jh->b_transaction == NULL) {
                 /* written-back checkpointed metadata buffer */
-                if (jh->b_jlist == BJ_None) {
-                        JBUFFER_TRACE(jh, "remove from checkpoint list");
-                        __jbd2_journal_remove_checkpoint(jh);
-                }
+                JBUFFER_TRACE(jh, "remove from checkpoint list");
+                __jbd2_journal_remove_checkpoint(jh);
         }
         spin_unlock(&journal->j_list_lock);
 out:
@@ -1949,6 +1977,8 @@ zap_buffer_unlocked:
         clear_buffer_mapped(bh);
         clear_buffer_req(bh);
         clear_buffer_new(bh);
+        clear_buffer_delay(bh);
+        clear_buffer_unwritten(bh);
         bh->b_bdev = NULL;
         return may_free;
 }