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@linux.ibm.com>
Link: https://lore.kernel.org/r/20220704054603.21462-1-ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index a6d71a41a0c4deceaae5ac71977e57041229c5fa..9e84a5597f42899489c7f7a31494e118e62ef3c4 100644 (file)
--- 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;
 }