From 85c8f176a6111ecde9c158109989dbd445a0e59a Mon Sep 17 00:00:00 2001
From: Andrew Perepechko <andrew.perepechko@seagate.com>
Date: Sun, 30 Apr 2017 00:46:35 -0400
Subject: [PATCH] ext4: preload block group descriptors
With enabled meta_bg option block group descriptors
reading IO is not sequential and requires optimization.
Signed-off-by: Andrew Perepechko <andrew.perepechko@seagate.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
fs/ext4/super.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9ec8963ba6049..9a40e0c16dcc7 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3879,6 +3879,12 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
bgl_lock_init(sbi->s_blockgroup_lock);
+ /* Pre-read the descriptors into the buffer cache */
+ for (i = 0; i < db_count; i++) {
+ block = descriptor_loc(sb, logical_sb_block, i);
+ sb_breadahead(sb, block);
+ }
+
for (i = 0; i < db_count; i++) {
block = descriptor_loc(sb, logical_sb_block, i);
sbi->s_group_desc[i] = sb_bread_unmovable(sb, block);
--
2.30.2