jbd2: Use tracepoints for history file

The /proc/fs/jbd2/<dev>/history was maintained manually; by using
tracepoints, we can get all of the existing functionality of the /proc
file plus extra capabilities thanks to the ftrace infrastructure.  We
save memory as a bonus.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 5d70b3e6d49b..ca0f5eb62b20 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -643,6 +643,7 @@ out:
 
 int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
 {
+        struct transaction_chp_stats_s *stats;
         transaction_t *transaction;
         journal_t *journal;
         int ret = 0;
@@ -679,6 +680,12 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh)
 
         /* 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);
         kfree(transaction);