Re: [GIT PULL] ext4 update for 2.6.36

[Linus Torvalds <torvalds@linux-foundation.org>]

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On Thu, Aug 5, 2010 at 9:23 PM, Theodore Ts'o <tytso@mit.edu> wrote:
>
> Which is hopefully what you want.  If you want exactly what is shown
> below, you can also pull the "next" branch, which omits the merge, and
> then you can deal with the merge conflict by hand.  The results should
> be the same either way.

I did that just to see what it looked like.

One annoyance: I now get

  fs/jbd2/transaction.c: In function ‘start_this_handle’:
  fs/jbd2/transaction.c:98: warning: unused variable ‘ts’

due to that 'ts' thing only being used for the CONFIG_JBD2_DEBUG case.
Please fix. I'd suggest putting that CONFIG_JBD2_DEBUG code in a
helper function of its own, and declaring 'ts' there instead.
Suggested patch (but with a horrible helper function name) attached.

               Linus

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 fs/jbd2/transaction.c |   29 ++++++++++++++++++-----------
 1 files changed, 18 insertions(+), 11 deletions(-)

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index d95cc9d..037d65d 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -81,6 +81,23 @@ jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
  * of that one update.
  */
 
+static inline void start_handle_debug(transaction_t *transaction)
+{
+#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);
+		spin_lock(&transaction->t_handle_lock);
+		if (ts > transaction->t_max_wait)
+			transaction->t_max_wait = ts;
+		spin_unlock(&transaction->t_handle_lock);
+	}
+#endif
+}
+
+
 /*
  * start_this_handle: Given a handle, deal with any locking or stalling
  * needed to make sure that there is enough journal space for the handle
@@ -95,7 +112,6 @@ static int start_this_handle(journal_t *journal, handle_t *handle,
 	int needed;
 	int nblocks = handle->h_buffer_credits;
 	transaction_t *new_transaction = NULL;
-	unsigned long ts = jiffies;
 
 	if (nblocks > journal->j_max_transaction_buffers) {
 		printk(KERN_ERR "JBD: %s wants too many credits (%d > %d)\n",
@@ -250,16 +266,7 @@ repeat:
 	 * separate flag, eventually, so we can enable this
 	 * independently of debugging.
 	 */
-#ifdef CONFIG_JBD2_DEBUG
-	if (jbd2_journal_enable_debug &&
-	    time_after(transaction->t_start, ts)) {
-		ts = jbd2_time_diff(ts, transaction->t_start);
-		spin_lock(&transaction->t_handle_lock);
-		if (ts > transaction->t_max_wait)
-			transaction->t_max_wait = ts;
-		spin_unlock(&transaction->t_handle_lock);
-	}
-#endif
+	start_handle_debug(transaction);
 	handle->h_transaction = transaction;
 	atomic_inc(&transaction->t_updates);
 	atomic_inc(&transaction->t_handle_count);