[DLM] canceling deadlocked lock

Add a function that can be used through libdlm by a system daemon to cancel
another process's deadlocked lock.  A completion ast with EDEADLK is returned
to the process waiting for the lock.

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

1 files changed, 25 insertions, 0 deletions

diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index 329da1b5285f..6438941ab1f8 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -156,6 +156,7 @@ static int lkb_is_endoflife(struct dlm_lkb *lkb, int sb_status, int type)
                 return 1;
         case -DLM_ECANCEL:
         case -ETIMEDOUT:
+        case -EDEADLK:
                 if (lkb->lkb_grmode == DLM_LOCK_IV)
                         return 1;
                 break;
@@ -320,6 +321,22 @@ static int device_user_unlock(struct dlm_user_proc *proc,
         return error;
 }
 
+static int device_user_deadlock(struct dlm_user_proc *proc,
+                                struct dlm_lock_params *params)
+{
+        struct dlm_ls *ls;
+        int error;
+
+        ls = dlm_find_lockspace_local(proc->lockspace);
+        if (!ls)
+                return -ENOENT;
+
+        error = dlm_user_deadlock(ls, params->flags, params->lkid);
+
+        dlm_put_lockspace(ls);
+        return error;
+}
+
 static int create_misc_device(struct dlm_ls *ls, char *name)
 {
         int error, len;
@@ -545,6 +562,14 @@ static ssize_t device_write(struct file *file, const char __user *buf,
                 error = device_user_unlock(proc, &kbuf->i.lock);
                 break;
 
+        case DLM_USER_DEADLOCK:
+                if (!proc) {
+                        log_print("no locking on control device");
+                        goto out_sig;
+                }
+                error = device_user_deadlock(proc, &kbuf->i.lock);
+                break;
+
         case DLM_USER_CREATE_LOCKSPACE:
                 if (proc) {
                         log_print("create/remove only on control device");