This patch implements DLM_PLOCK_OP_CANCEL to try to delete waiters for a
lock request which are waiting to being granted. If the waiter can be
deleted the reply is 0. If the waiter cannot be found it will return
-ENOENT to the kernel, either that there never was be a waiter or we were
to late to cancel the lock request.
---
changes since v2:
- drop the no reply flag
- always send a reply on DLM_PLOCK_OP_CANCEL
- return -ENOENT instead of 1 to indicated cancellation failed
dlm_controld/plock.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 44 insertions(+)
diff --git a/dlm_controld/plock.c b/dlm_controld/plock.c
index a91aecb0..1944cd59 100644
--- a/dlm_controld/plock.c
+++ b/dlm_controld/plock.c
@@ -9,6 +9,10 @@
#include "dlm_daemon.h"
#include <linux/dlm_plock.h>
+#ifndef DLM_PLOCK_OP_CANCEL
+#define DLM_PLOCK_OP_CANCEL 4
+#endif
+
static uint32_t plock_read_count;
static uint32_t plock_recv_count;
static uint32_t plock_rate_delays;
@@ -132,6 +136,8 @@ static const char *op_str(int optype)
switch (optype) {
case DLM_PLOCK_OP_LOCK:
return "LK";
+ case DLM_PLOCK_OP_CANCEL:
+ return "CL";
case DLM_PLOCK_OP_UNLOCK:
return "UN";
case DLM_PLOCK_OP_GET:
@@ -741,6 +747,40 @@ static void do_lock(struct lockspace *ls, struct
dlm_plock_info *in,
put_resource(ls, r);
}
+static int remove_waiter(const struct resource *r, const struct dlm_plock_info
*in)
+{
+ struct lock_waiter *w;
+
+ list_for_each_entry(w, &r->waiters, list) {
+ if (w->info.nodeid == in->nodeid &&
+ w->info.fsid == in->fsid &&
+ w->info.number == in->number &&
+ w->info.owner == in->owner &&
+ w->info.pid == in->pid &&
+ w->info.start == in->start &&
+ w->info.end == in->end &&
+ w->info.ex == in->ex) {
+ list_del(&w->list);
+ free(w);
+ return 0;
+ }
+ }
+
+ return -ENOENT;
+}
+
+static void do_cancel(struct lockspace *ls, struct dlm_plock_info *in,
+ struct resource *r)
+{
+ int rv;
+
+ rv = remove_waiter(r, in);
+ if (in->nodeid == our_nodeid)
+ write_result(in, rv);
+
+ put_resource(ls, r);
+}
+
static void do_unlock(struct lockspace *ls, struct dlm_plock_info *in,
struct resource *r)
{
@@ -806,6 +846,10 @@ static void __receive_plock(struct lockspace *ls, struct
dlm_plock_info *in,
ls->last_plock_time = monotime();
do_lock(ls, in, r);
break;
+ case DLM_PLOCK_OP_CANCEL:
+ ls->last_plock_time = monotime();
+ do_cancel(ls, in, r);
+ break;
case DLM_PLOCK_OP_UNLOCK:
ls->last_plock_time = monotime();
do_unlock(ls, in, r);
--
2.31.1
