Patch "ext4: disable synchronous transaction batching if max_batch_time==0" has been added to the 3.14-stable tree

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This is a note to let you know that I've just added the patch titled

    ext4: disable synchronous transaction batching if max_batch_time==0

to the 3.14-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ext4-disable-synchronous-transaction-batching-if-max_batch_time-0.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 5dd214248f94d430d70e9230bda72f2654ac88a8 Mon Sep 17 00:00:00 2001
From: Eric Sandeen <sandeen@xxxxxxxxxx>
Date: Sat, 5 Jul 2014 19:18:22 -0400
Subject: ext4: disable synchronous transaction batching if max_batch_time==0

From: Eric Sandeen <sandeen@xxxxxxxxxx>

commit 5dd214248f94d430d70e9230bda72f2654ac88a8 upstream.

The mount manpage says of the max_batch_time option,

	This optimization can be turned off entirely
	by setting max_batch_time to 0.

But the code doesn't do that.  So fix the code to do
that.

Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/ext4/super.c       |    2 --
 fs/jbd2/transaction.c |    5 ++++-
 2 files changed, 4 insertions(+), 3 deletions(-)

--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1519,8 +1519,6 @@ static int handle_mount_opt(struct super
 			arg = JBD2_DEFAULT_MAX_COMMIT_AGE;
 		sbi->s_commit_interval = HZ * arg;
 	} else if (token == Opt_max_batch_time) {
-		if (arg == 0)
-			arg = EXT4_DEF_MAX_BATCH_TIME;
 		sbi->s_max_batch_time = arg;
 	} else if (token == Opt_min_batch_time) {
 		sbi->s_min_batch_time = arg;
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1590,9 +1590,12 @@ int jbd2_journal_stop(handle_t *handle)
 	 * to perform a synchronous write.  We do this to detect the
 	 * case where a single process is doing a stream of sync
 	 * writes.  No point in waiting for joiners in that case.
+	 *
+	 * Setting max_batch_time to 0 disables this completely.
 	 */
 	pid = current->pid;
-	if (handle->h_sync && journal->j_last_sync_writer != pid) {
+	if (handle->h_sync && journal->j_last_sync_writer != pid &&
+	    journal->j_max_batch_time) {
 		u64 commit_time, trans_time;
 
 		journal->j_last_sync_writer = pid;


Patches currently in stable-queue which might be from sandeen@xxxxxxxxxx are

queue-3.14/ext4-disable-synchronous-transaction-batching-if-max_batch_time-0.patch
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