fs: add dirtytime_expire_seconds sysctl

Add a tuning knob so we can adjust the dirtytime expiration timeout,
which is very useful for testing lazytime.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>

1 files changed, 11 insertions, 0 deletions

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 2cfcd74faf87..32a8bbd7a9ad 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1188,6 +1188,17 @@ static int __init start_dirtytime_writeback(void)
 }
 __initcall(start_dirtytime_writeback);
 
+int dirtytime_interval_handler(struct ctl_table *table, int write,
+                               void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+        int ret;
+
+        ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+        if (ret == 0 && write)
+                mod_delayed_work(system_wq, &dirtytime_work, 0);
+        return ret;
+}
+
 static noinline void block_dump___mark_inode_dirty(struct inode *inode)
 {
         if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) {