ext4: add fsync batch tuning knobs

Add new mount options, min_batch_time and max_batch_time, which
controls how long the jbd2 layer should wait for additional filesystem
operations to get batched with a synchronous write transaction.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/ext4/ext4_sb.h b/fs/ext4/ext4_sb.h
index 3db800f399a6..039b6ea1a042 100644
--- a/fs/ext4/ext4_sb.h
+++ b/fs/ext4/ext4_sb.h
@@ -74,6 +74,8 @@ struct ext4_sb_info {
         struct journal_s *s_journal;
         struct list_head s_orphan;
         unsigned long s_commit_interval;
+        u32 s_max_batch_time;
+        u32 s_min_batch_time;
         struct block_device *journal_bdev;
 #ifdef CONFIG_JBD2_DEBUG
         struct timer_list turn_ro_timer;        /* For turning read-only (crash simulation) */