jbd2: Fix the wrong calculation of t_max_wait in update_t_max_wait

t_max_wait is added in commit 8e85fb3f to indicate how long we
were waiting for new transaction to start. In commit 6d0bf005,
it is moved to another function named update_t_max_wait to
avoid a build warning. But the wrong thing is that the original
'ts' is initialized in the start of function start_this_handle
and we can calculate t_max_wait in the right way. while with
this change, ts is initialized within the function and t_max_wait
can never be calculated right.

This patch moves the initialization of ts to the original beginning
of start_this_handle and pass it to function update_t_max_wait so
that it can be calculated right and the build warning is avoided also.

Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 05fa77a23711f8db041cac46984452451daae70c..85a055ef93fedb138e44918227426abd3f34eb46 100644 (file)
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -82,7 +82,7 @@ jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
  */
 
 /*
- * Update transiaction's maximum wait time, if debugging is enabled.
+ * Update transaction's maximum wait time, if debugging is enabled.
  *
  * In order for t_max_wait to be reliable, it must be protected by a
  * lock.  But doing so will mean that start_this_handle() can not be
@@ -91,11 +91,10 @@ jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
  * means that maximum wait time reported by the jbd2_run_stats
  * tracepoint will always be zero.
  */
-static inline void update_t_max_wait(transaction_t *transaction)
+static inline void update_t_max_wait(transaction_t *transaction,
+                                    unsigned long ts)
 {
 #ifdef CONFIG_JBD2_DEBUG
-       unsigned long ts = jiffies;
-
        if (jbd2_journal_enable_debug &&
            time_after(transaction->t_start, ts)) {
                ts = jbd2_time_diff(ts, transaction->t_start);
@@ -121,6 +120,7 @@ static int start_this_handle(journal_t *journal, handle_t *handle,
        tid_t           tid;
        int             needed, need_to_start;
        int             nblocks = handle->h_buffer_credits;
+       unsigned long ts = jiffies;
 
        if (nblocks > journal->j_max_transaction_buffers) {
                printk(KERN_ERR "JBD: %s wants too many credits (%d > %d)\n",
@@ -271,7 +271,7 @@ repeat:
        /* OK, account for the buffers that this operation expects to
         * use and add the handle to the running transaction. 
         */
-       update_t_max_wait(transaction);
+       update_t_max_wait(transaction, ts);
        handle->h_transaction = transaction;
        atomic_inc(&transaction->t_updates);
        atomic_inc(&transaction->t_handle_count);