linux-kernel - [PATCH] ext4: Reflect mb_optimize

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Message-Id: <20220704054603.21462-1-ojaswin@linux.ibm.com>
Date:   Mon,  4 Jul 2022 11:16:03 +0530
From:   Ojaswin Mujoo <ojaswin@...ux.ibm.com>
To:     linux-ext4@...r.kernel.org
Cc:     "Theodore Ts'o" <tytso@....edu>,
        Ritesh Harjani <riteshh@...ux.ibm.com>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] ext4: Reflect mb_optimize_scan value in options file

Add support to display the mb_optimize_scan value in
/proc/fs/ext4/<dev>/options file. The option is only
displayed when the value is non default.

Signed-off-by: Ojaswin Mujoo <ojaswin@...ux.ibm.com>
---
 fs/ext4/super.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 845f2f8aee5f..e3fd50b0d6b7 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3011,6 +3011,15 @@ static int _ext4_show_options(struct seq_file *seq, struct super_block *sb,
 	} else if (test_opt2(sb, DAX_INODE)) {
 		SEQ_OPTS_PUTS("dax=inode");
 	}
+
+	if (sbi->s_groups_count >= MB_DEFAULT_LINEAR_SCAN_THRESHOLD &&
+			!test_opt2(sb, MB_OPTIMIZE_SCAN)) {
+		SEQ_OPTS_PUTS("mb_optimize_scan=0");
+	} else if (sbi->s_groups_count < MB_DEFAULT_LINEAR_SCAN_THRESHOLD &&
+			test_opt2(sb, MB_OPTIMIZE_SCAN)) {
+		SEQ_OPTS_PUTS("mb_optimize_scan=1");
+	}
+
 	ext4_show_quota_options(seq, sb);
 	return 0;
 }
-- 
2.27.0