dlm: clear defunct cancel state

When a conversion completes successfully and finds that a cancel
of the convert is still in progress (which is now a moot point),
preemptively clear the state associated with outstanding cancel.
That state could cause a subsequent conversion to be ignored.

Also, improve the consistency and content of error and debug
messages in this area.

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

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 01e7d39c5fba8d55a4fa1a4bd8f64e13d4c32a95..8cb92046a5844c1a9f1148f5c1770c8aa7744ce2 100644 (file)
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -835,7 +835,7 @@ static int add_to_waiters(struct dlm_lkb *lkb, int mstype)
                lkb->lkb_wait_count++;
                hold_lkb(lkb);
 
-               log_debug(ls, "add overlap %x cur %d new %d count %d flags %x",
+               log_debug(ls, "addwait %x cur %d overlap %d count %d f %x",
                          lkb->lkb_id, lkb->lkb_wait_type, mstype,
                          lkb->lkb_wait_count, lkb->lkb_flags);
                goto out;
@@ -851,7 +851,7 @@ static int add_to_waiters(struct dlm_lkb *lkb, int mstype)
        list_add(&lkb->lkb_wait_reply, &ls->ls_waiters);
  out:
        if (error)
-               log_error(ls, "add_to_waiters %x error %d flags %x %d %d %s",
+               log_error(ls, "addwait error %x %d flags %x %d %d %s",
                          lkb->lkb_id, error, lkb->lkb_flags, mstype,
                          lkb->lkb_wait_type, lkb->lkb_resource->res_name);
        mutex_unlock(&ls->ls_waiters_mutex);
@@ -863,23 +863,55 @@ static int add_to_waiters(struct dlm_lkb *lkb, int mstype)
    request reply on the requestqueue) between dlm_recover_waiters_pre() which
    set RESEND and dlm_recover_waiters_post() */
 
-static int _remove_from_waiters(struct dlm_lkb *lkb, int mstype)
+static int _remove_from_waiters(struct dlm_lkb *lkb, int mstype,
+                               struct dlm_message *ms)
 {
        struct dlm_ls *ls = lkb->lkb_resource->res_ls;
        int overlap_done = 0;
 
        if (is_overlap_unlock(lkb) && (mstype == DLM_MSG_UNLOCK_REPLY)) {
+               log_debug(ls, "remwait %x unlock_reply overlap", lkb->lkb_id);
                lkb->lkb_flags &= ~DLM_IFL_OVERLAP_UNLOCK;
                overlap_done = 1;
                goto out_del;
        }
 
        if (is_overlap_cancel(lkb) && (mstype == DLM_MSG_CANCEL_REPLY)) {
+               log_debug(ls, "remwait %x cancel_reply overlap", lkb->lkb_id);
                lkb->lkb_flags &= ~DLM_IFL_OVERLAP_CANCEL;
                overlap_done = 1;
                goto out_del;
        }
 
+       /* Cancel state was preemptively cleared by a successful convert,
+          see next comment, nothing to do. */
+
+       if ((mstype == DLM_MSG_CANCEL_REPLY) &&
+           (lkb->lkb_wait_type != DLM_MSG_CANCEL)) {
+               log_debug(ls, "remwait %x cancel_reply wait_type %d",
+                         lkb->lkb_id, lkb->lkb_wait_type);
+               return -1;
+       }
+
+       /* Remove for the convert reply, and premptively remove for the
+          cancel reply.  A convert has been granted while there's still
+          an outstanding cancel on it (the cancel is moot and the result
+          in the cancel reply should be 0).  We preempt the cancel reply
+          because the app gets the convert result and then can follow up
+          with another op, like convert.  This subsequent op would see the
+          lingering state of the cancel and fail with -EBUSY. */
+
+       if ((mstype == DLM_MSG_CONVERT_REPLY) &&
+           (lkb->lkb_wait_type == DLM_MSG_CONVERT) &&
+           is_overlap_cancel(lkb) && ms && !ms->m_result) {
+               log_debug(ls, "remwait %x convert_reply zap overlap_cancel",
+                         lkb->lkb_id);
+               lkb->lkb_wait_type = 0;
+               lkb->lkb_flags &= ~DLM_IFL_OVERLAP_CANCEL;
+               lkb->lkb_wait_count--;
+               goto out_del;
+       }
+
        /* N.B. type of reply may not always correspond to type of original
           msg due to lookup->request optimization, verify others? */
 
@@ -888,8 +920,8 @@ static int _remove_from_waiters(struct dlm_lkb *lkb, int mstype)
                goto out_del;
        }
 
-       log_error(ls, "remove_from_waiters lkid %x flags %x types %d %d",
-                 lkb->lkb_id, lkb->lkb_flags, mstype, lkb->lkb_wait_type);
+       log_error(ls, "remwait error %x reply %d flags %x no wait_type",
+                 lkb->lkb_id, mstype, lkb->lkb_flags);
        return -1;
 
  out_del:
@@ -899,7 +931,7 @@ static int _remove_from_waiters(struct dlm_lkb *lkb, int mstype)
           this would happen */
 
        if (overlap_done && lkb->lkb_wait_type) {
-               log_error(ls, "remove_from_waiters %x reply %d give up on %d",
+               log_error(ls, "remwait error %x reply %d wait_type %d overlap",
                          lkb->lkb_id, mstype, lkb->lkb_wait_type);
                lkb->lkb_wait_count--;
                lkb->lkb_wait_type = 0;
@@ -921,7 +953,7 @@ static int remove_from_waiters(struct dlm_lkb *lkb, int mstype)
        int error;
 
        mutex_lock(&ls->ls_waiters_mutex);
-       error = _remove_from_waiters(lkb, mstype);
+       error = _remove_from_waiters(lkb, mstype, NULL);
        mutex_unlock(&ls->ls_waiters_mutex);
        return error;
 }
@@ -936,7 +968,7 @@ static int remove_from_waiters_ms(struct dlm_lkb *lkb, struct dlm_message *ms)
 
        if (ms != &ls->ls_stub_ms)
                mutex_lock(&ls->ls_waiters_mutex);
-       error = _remove_from_waiters(lkb, ms->m_type);
+       error = _remove_from_waiters(lkb, ms->m_type, ms);
        if (ms != &ls->ls_stub_ms)
                mutex_unlock(&ls->ls_waiters_mutex);
        return error;
@@ -2083,6 +2115,11 @@ static int validate_lock_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
        lkb->lkb_timeout_cs = args->timeout;
        rv = 0;
  out:
+       if (rv)
+               log_debug(ls, "validate_lock_args %d %x %x %x %d %d %s",
+                         rv, lkb->lkb_id, lkb->lkb_flags, args->flags,
+                         lkb->lkb_status, lkb->lkb_wait_type,
+                         lkb->lkb_resource->res_name);
        return rv;
 }