Support changing configuration parameters using device-mapper messages
E.g.
dmsetup message vg1/lv1 0 high_watermark 60
Signed-off-by: Maged Mokhtar <mmokhtar@xxxxxxxxxxx>
---
drivers/md/dm-writecache.c | 68 +++++++++++++++++++++++++++++++++++
1 file changed, 68 insertions(+)
--- a/drivers/md/dm-writecache.c 2019-08-25 16:13:54.000000000 +0200
+++ b/drivers/md/dm-writecache.c 2019-09-21 16:22:23.000000000 +0200
@@ -1009,6 +1009,69 @@ static int process_flush_on_suspend_mesg
return 0;
}
+static int set_config_value(struct dm_writecache *wc, char *key, char *val)
+{
+ unsigned v,x;
+ if (sscanf(val, "%u", &v) != 1)
+ return -EINVAL;
+ if (!strcasecmp(key, "high_watermark")) {
+ if (v < 0 || v > 100)
+ return -EINVAL;
+ wc_lock(wc);
+ x = (uint64_t)wc->n_blocks * (100 - v);
+ x += 50;
+ do_div(x, 100);
+ if (wc->freelist_low_watermark < x) {
+ wc_unlock(wc);
+ return -EINVAL;
+ }
+ wc->freelist_high_watermark = x;
+ wc->high_wm_percent_set = true;
+ if (wc->freelist_size + wc->writeback_size
+ <= wc->freelist_high_watermark)
+ queue_work(wc->writeback_wq, &wc->writeback_work);
+ wc_unlock(wc);
+ }
+ else if (!strcasecmp(key, "low_watermark")) {
+ if (v < 0 || v > 100)
+ return -EINVAL;
+ wc_lock(wc);
+ x = (uint64_t)wc->n_blocks * (100 - v);
+ x += 50;
+ do_div(x, 100);
+ if (x < wc->freelist_high_watermark) {
+ wc_unlock(wc);
+ return -EINVAL;
+ }
+ wc->freelist_low_watermark = x;
+ wc->low_wm_percent_set = true;
+ wc_unlock(wc);
+ }
+ else if (!strcasecmp(key, "writeback_jobs")) {
+ wc_lock(wc);
+ wc->max_writeback_jobs = v;
+ wc->max_writeback_jobs_set = true;
+ wc_unlock(wc);
+ }
+ else if (!strcasecmp(key, "autocommit_blocks")) {
+ wc_lock(wc);
+ wc->autocommit_blocks = v;
+ wc->autocommit_blocks_set = true;
+ wc_unlock(wc);
+ }
+ else if (!strcasecmp(key, "autocommit_time")) {
+ if (v < 1 || v > 3600000)
+ return -EINVAL;
+ wc_lock(wc);
+ wc->autocommit_jiffies = msecs_to_jiffies(v);
+ wc->autocommit_time_set = true;
+ wc_unlock(wc);
+ }
+ else
+ return -EINVAL;
+ return 0;
+}
+
static int writecache_message(struct dm_target *ti, unsigned argc,
char **argv,
char *result, unsigned maxlen)
{
@@ -1019,6 +1082,11 @@ static int writecache_message(struct dm_
r = process_flush_mesg(argc, argv, wc);
else if (!strcasecmp(argv[0], "flush_on_suspend"))
r = process_flush_on_suspend_mesg(argc, argv, wc);
+ else if (argc==2) {
+ r = set_config_value(wc, argv[0], argv[1]);
+ if (r==-EINVAL)
+ DMERR("invalid message received: %s %s", argv[0], argv[1]);
+ }
else
DMERR("unrecognised message received: %s", argv[0]);
--
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