1 files changed, 68 insertions, 24 deletions

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 5e44d7bbd8fc..eab98d76dbe1 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -448,18 +448,23 @@ xfs_iget_check_free_state(
 }
 
 /* Make all pending inactivation work start immediately. */
-static void
+static bool
 xfs_inodegc_queue_all(
 	struct xfs_mount	*mp)
 {
 	struct xfs_inodegc	*gc;
 	int			cpu;
+	bool			ret = false;
 
 	for_each_online_cpu(cpu) {
 		gc = per_cpu_ptr(mp->m_inodegc, cpu);
-		if (!llist_empty(&gc->list))
-			queue_work_on(cpu, mp->m_inodegc_wq, &gc->work);
+		if (!llist_empty(&gc->list)) {
+			mod_delayed_work_on(cpu, mp->m_inodegc_wq, &gc->work, 0);
+			ret = true;
+		}
 	}
+
+	return ret;
 }
 
 /*
@@ -1851,11 +1856,13 @@ void
 xfs_inodegc_worker(
 	struct work_struct	*work)
 {
-	struct xfs_inodegc	*gc = container_of(work, struct xfs_inodegc,
-							work);
+	struct xfs_inodegc	*gc = container_of(to_delayed_work(work),
+						struct xfs_inodegc, work);
 	struct llist_node	*node = llist_del_all(&gc->list);
 	struct xfs_inode	*ip, *n;
 
+	ASSERT(gc->cpu == smp_processor_id());
+
 	WRITE_ONCE(gc->items, 0);
 
 	if (!node)
@@ -1872,42 +1879,69 @@ xfs_inodegc_worker(
 }
 
 /*
- * Force all currently queued inode inactivation work to run immediately and
- * wait for the work to finish.
+ * Expedite all pending inodegc work to run immediately. This does not wait for
+ * completion of the work.
  */
 void
-xfs_inodegc_flush(
+xfs_inodegc_push(
 	struct xfs_mount	*mp)
 {
 	if (!xfs_is_inodegc_enabled(mp))
 		return;
+	trace_xfs_inodegc_push(mp, __return_address);
+	xfs_inodegc_queue_all(mp);
+}
 
+/*
+ * Force all currently queued inode inactivation work to run immediately and
+ * wait for the work to finish.
+ */
+void
+xfs_inodegc_flush(
+	struct xfs_mount	*mp)
+{
+	xfs_inodegc_push(mp);
 	trace_xfs_inodegc_flush(mp, __return_address);
-
-	xfs_inodegc_queue_all(mp);
 	flush_workqueue(mp->m_inodegc_wq);
 }
 
 /*
  * Flush all the pending work and then disable the inode inactivation background
- * workers and wait for them to stop.
+ * workers and wait for them to stop.  Caller must hold sb->s_umount to
+ * coordinate changes in the inodegc_enabled state.
  */
 void
 xfs_inodegc_stop(
 	struct xfs_mount	*mp)
 {
+	bool			rerun;
+
 	if (!xfs_clear_inodegc_enabled(mp))
 		return;
 
+	/*
+	 * Drain all pending inodegc work, including inodes that could be
+	 * queued by racing xfs_inodegc_queue or xfs_inodegc_shrinker_scan
+	 * threads that sample the inodegc state just prior to us clearing it.
+	 * The inodegc flag state prevents new threads from queuing more
+	 * inodes, so we queue pending work items and flush the workqueue until
+	 * all inodegc lists are empty.  IOWs, we cannot use drain_workqueue
+	 * here because it does not allow other unserialized mechanisms to
+	 * reschedule inodegc work while this draining is in progress.
+	 */
 	xfs_inodegc_queue_all(mp);
-	drain_workqueue(mp->m_inodegc_wq);
+	do {
+		flush_workqueue(mp->m_inodegc_wq);
+		rerun = xfs_inodegc_queue_all(mp);
+	} while (rerun);
 
 	trace_xfs_inodegc_stop(mp, __return_address);
 }
 
 /*
  * Enable the inode inactivation background workers and schedule deferred inode
- * inactivation work if there is any.
+ * inactivation work if there is any.  Caller must hold sb->s_umount to
+ * coordinate changes in the inodegc_enabled state.
  */
 void
 xfs_inodegc_start(
@@ -2021,6 +2055,7 @@ xfs_inodegc_queue(
 	struct xfs_inodegc	*gc;
 	int			items;
 	unsigned int		shrinker_hits;
+	unsigned long		queue_delay = 1;
 
 	trace_xfs_inode_set_need_inactive(ip);
 	spin_lock(&ip->i_flags_lock);
@@ -2032,19 +2067,27 @@ xfs_inodegc_queue(
 	items = READ_ONCE(gc->items);
 	WRITE_ONCE(gc->items, items + 1);
 	shrinker_hits = READ_ONCE(gc->shrinker_hits);
-	put_cpu_ptr(gc);
 
-	if (!xfs_is_inodegc_enabled(mp))
+	/*
+	 * We queue the work while holding the current CPU so that the work
+	 * is scheduled to run on this CPU.
+	 */
+	if (!xfs_is_inodegc_enabled(mp)) {
+		put_cpu_ptr(gc);
 		return;
-
-	if (xfs_inodegc_want_queue_work(ip, items)) {
-		trace_xfs_inodegc_queue(mp, __return_address);
-		queue_work(mp->m_inodegc_wq, &gc->work);
 	}
 
+	if (xfs_inodegc_want_queue_work(ip, items))
+		queue_delay = 0;
+
+	trace_xfs_inodegc_queue(mp, __return_address);
+	mod_delayed_work_on(current_cpu(), mp->m_inodegc_wq, &gc->work,
+			queue_delay);
+	put_cpu_ptr(gc);
+
 	if (xfs_inodegc_want_flush_work(ip, items, shrinker_hits)) {
 		trace_xfs_inodegc_throttle(mp, __return_address);
-		flush_work(&gc->work);
+		flush_delayed_work(&gc->work);
 	}
 }
 
@@ -2061,7 +2104,7 @@ xfs_inodegc_cpu_dead(
 	unsigned int		count = 0;
 
 	dead_gc = per_cpu_ptr(mp->m_inodegc, dead_cpu);
-	cancel_work_sync(&dead_gc->work);
+	cancel_delayed_work_sync(&dead_gc->work);
 
 	if (llist_empty(&dead_gc->list))
 		return;
@@ -2080,12 +2123,13 @@ xfs_inodegc_cpu_dead(
 	llist_add_batch(first, last, &gc->list);
 	count += READ_ONCE(gc->items);
 	WRITE_ONCE(gc->items, count);
-	put_cpu_ptr(gc);
 
 	if (xfs_is_inodegc_enabled(mp)) {
 		trace_xfs_inodegc_queue(mp, __return_address);
-		queue_work(mp->m_inodegc_wq, &gc->work);
+		mod_delayed_work_on(current_cpu(), mp->m_inodegc_wq, &gc->work,
+				0);
 	}
+	put_cpu_ptr(gc);
 }
 
 /*
@@ -2180,7 +2224,7 @@ xfs_inodegc_shrinker_scan(
 			unsigned int	h = READ_ONCE(gc->shrinker_hits);
 
 			WRITE_ONCE(gc->shrinker_hits, h + 1);
-			queue_work_on(cpu, mp->m_inodegc_wq, &gc->work);
+			mod_delayed_work_on(cpu, mp->m_inodegc_wq, &gc->work, 0);
 			no_items = false;
 		}
 	}