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 3.15-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-3.15 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 @@ -1524,8 +1524,6 @@ 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 @@ -1588,9 +1588,12 @@ 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-3.15/ext4-disable-synchronous-transaction-batching-if-max_batch_time-0.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html