[GFS2] make lock_dlm drop_count tunable in sysfs

We want to be able to change or disable the default drop_count (number at
which the dlm asks gfs to limit the the number of locks it's holding).
Add it to the collection of sysfs tunables for an fs.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/fs/gfs2/locking/dlm/sysfs.c b/fs/gfs2/locking/dlm/sysfs.c
index 29ae06f94944..4746b884662d 100644
--- a/fs/gfs2/locking/dlm/sysfs.c
+++ b/fs/gfs2/locking/dlm/sysfs.c
@@ -116,6 +116,17 @@ static ssize_t recover_status_show(struct gdlm_ls *ls, char *buf)
         return sprintf(buf, "%d\n", ls->recover_jid_status);
 }
 
+static ssize_t drop_count_show(struct gdlm_ls *ls, char *buf)
+{
+        return sprintf(buf, "%d\n", ls->drop_locks_count);
+}
+
+static ssize_t drop_count_store(struct gdlm_ls *ls, const char *buf, size_t len)
+{
+        ls->drop_locks_count = simple_strtol(buf, NULL, 0);
+        return len;
+}
+
 struct gdlm_attr {
         struct attribute attr;
         ssize_t (*show)(struct gdlm_ls *, char *);
@@ -135,6 +146,7 @@ GDLM_ATTR(first_done,     0444, first_done_show,     NULL);
 GDLM_ATTR(recover,        0644, recover_show,        recover_store);
 GDLM_ATTR(recover_done,   0444, recover_done_show,   NULL);
 GDLM_ATTR(recover_status, 0444, recover_status_show, NULL);
+GDLM_ATTR(drop_count,     0644, drop_count_show,     drop_count_store);
 
 static struct attribute *gdlm_attrs[] = {
         &gdlm_attr_proto_name.attr,
@@ -147,6 +159,7 @@ static struct attribute *gdlm_attrs[] = {
         &gdlm_attr_recover.attr,
         &gdlm_attr_recover_done.attr,
         &gdlm_attr_recover_status.attr,
+        &gdlm_attr_drop_count.attr,
         NULL,
 };