From ab7ff0fcad9574ff1600c0888d83b7a53357464b Mon Sep 17 00:00:00 2001
From: Patrick Donnelly <pdonnell@redhat.com>
Date: Sat, 19 Jan 2019 20:40:11 -0800
Subject: [PATCH] mds: adapt drop cache for incremental trim

Signed-off-by: Patrick Donnelly <pdonnell@redhat.com>
(cherry picked from commit b750b3bb25d3c0cbad7a24ad6c7fd215d1b16395)
---
 src/mds/MDSRank.cc | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/mds/MDSRank.cc b/src/mds/MDSRank.cc
index 2e392ce95ff37..d27251d6cf7ad 100644
--- a/src/mds/MDSRank.cc
+++ b/src/mds/MDSRank.cc
@@ -382,13 +382,20 @@ private:
   void trim_cache() {
     dout(20) << __func__ << dendl;
 
-    if (!mdcache->trim(UINT64_MAX)) {
-      cmd_err(f, "failed to trim cache");
-      complete(-EINVAL);
-      return;
+    auto p = mdcache->trim(UINT64_MAX);
+    auto& throttled = p.first;
+    auto& count = p.second;
+    dout(10) << __func__
+             << (throttled ? " (throttled)" : "")
+             << " trimmed " << count << " caps" << dendl;
+    if (throttled && count > 0) {
+      auto timer = new FunctionContext([this](int _) {
+        trim_cache();
+      });
+      mds->timer.add_event_after(1.0, timer);
+    } else {
+      cache_status();
     }
-
-    cache_status();
   }
 
   void cache_status() {
-- 
2.39.5