1 files changed, 92 insertions, 2 deletions

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 661350989e98..0290a22ebccf 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -305,6 +305,11 @@ static void gfs2_holder_wake(struct gfs2_holder *gh)
 	clear_bit(HIF_WAIT, &gh->gh_iflags);
 	smp_mb__after_atomic();
 	wake_up_bit(&gh->gh_iflags, HIF_WAIT);
+	if (gh->gh_flags & GL_ASYNC) {
+		struct gfs2_sbd *sdp = gh->gh_gl->gl_name.ln_sbd;
+
+		wake_up(&sdp->sd_async_glock_wait);
+	}
 }
 
 /**
@@ -959,6 +964,91 @@ int gfs2_glock_wait(struct gfs2_holder *gh)
 	return gh->gh_error;
 }
 
+static int glocks_pending(unsigned int num_gh, struct gfs2_holder *ghs)
+{
+	int i;
+
+	for (i = 0; i < num_gh; i++)
+		if (test_bit(HIF_WAIT, &ghs[i].gh_iflags))
+			return 1;
+	return 0;
+}
+
+/**
+ * gfs2_glock_async_wait - wait on multiple asynchronous glock acquisitions
+ * @num_gh: the number of holders in the array
+ * @ghs: the glock holder array
+ *
+ * Returns: 0 on success, meaning all glocks have been granted and are held.
+ *          -ESTALE if the request timed out, meaning all glocks were released,
+ *          and the caller should retry the operation.
+ */
+
+int gfs2_glock_async_wait(unsigned int num_gh, struct gfs2_holder *ghs)
+{
+	struct gfs2_sbd *sdp = ghs[0].gh_gl->gl_name.ln_sbd;
+	int i, ret = 0, timeout = 0;
+	unsigned long start_time = jiffies;
+	bool keep_waiting;
+
+	might_sleep();
+	/*
+	 * Total up the (minimum hold time * 2) of all glocks and use that to
+	 * determine the max amount of time we should wait.
+	 */
+	for (i = 0; i < num_gh; i++)
+		timeout += ghs[i].gh_gl->gl_hold_time << 1;
+
+wait_for_dlm:
+	if (!wait_event_timeout(sdp->sd_async_glock_wait,
+				!glocks_pending(num_gh, ghs), timeout))
+		ret = -ESTALE; /* request timed out. */
+
+	/*
+	 * If dlm granted all our requests, we need to adjust the glock
+	 * minimum hold time values according to how long we waited.
+	 *
+	 * If our request timed out, we need to repeatedly release any held
+	 * glocks we acquired thus far to allow dlm to acquire the remaining
+	 * glocks without deadlocking.  We cannot currently cancel outstanding
+	 * glock acquisitions.
+	 *
+	 * The HIF_WAIT bit tells us which requests still need a response from
+	 * dlm.
+	 *
+	 * If dlm sent us any errors, we return the first error we find.
+	 */
+	keep_waiting = false;
+	for (i = 0; i < num_gh; i++) {
+		/* Skip holders we have already dequeued below. */
+		if (!gfs2_holder_queued(&ghs[i]))
+			continue;
+		/* Skip holders with a pending DLM response. */
+		if (test_bit(HIF_WAIT, &ghs[i].gh_iflags)) {
+			keep_waiting = true;
+			continue;
+		}
+
+		if (test_bit(HIF_HOLDER, &ghs[i].gh_iflags)) {
+			if (ret == -ESTALE)
+				gfs2_glock_dq(&ghs[i]);
+			else
+				gfs2_glock_update_hold_time(ghs[i].gh_gl,
+							    start_time);
+		}
+		if (!ret)
+			ret = ghs[i].gh_error;
+	}
+
+	if (keep_waiting)
+		goto wait_for_dlm;
+
+	/*
+	 * At this point, we've either acquired all locks or released them all.
+	 */
+	return ret;
+}
+
 /**
  * handle_callback - process a demote request
  * @gl: the glock
@@ -1025,9 +1115,9 @@ __acquires(&gl->gl_lockref.lock)
 	struct gfs2_holder *gh2;
 	int try_futile = 0;
 
-	BUG_ON(gh->gh_owner_pid == NULL);
+	GLOCK_BUG_ON(gl, gh->gh_owner_pid == NULL);
 	if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
-		BUG();
+		GLOCK_BUG_ON(gl, true);
 
 	if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
 		if (test_bit(GLF_LOCK, &gl->gl_flags))