From 0f72a8a0cf5d2a4950f119f2434f73169f112e31 Mon Sep 17 00:00:00 2001
From: Thomas Waldmann <tw@waldmann-edv.de>
Date: Mon, 11 Mar 2019 02:27:41 +0100
Subject: [PATCH] lrucache: regularly remove old FDs, fixes #4427

---
 src/borg/lrucache.py   |  1 -
 src/borg/repository.py | 25 ++++++++++++++++---------
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/src/borg/lrucache.py b/src/borg/lrucache.py
index d362bc92b..4f7f1f829 100644
--- a/src/borg/lrucache.py
+++ b/src/borg/lrucache.py
@@ -50,7 +50,6 @@ class LRUCache:
             self._dispose(value)
         self._cache.clear()
 
-    # useful for testing
     def items(self):
         return self._cache.items()
 
diff --git a/src/borg/repository.py b/src/borg/repository.py
index 3137d0809..ef70ccd69 100644
--- a/src/borg/repository.py
+++ b/src/borg/repository.py
@@ -1171,6 +1171,7 @@ class LoggedIO:
         self.segments_per_dir = segments_per_dir
         self.offset = 0
         self._write_fd = None
+        self._fds_cleaned = 0
 
     def close(self):
         self.close_segment()
@@ -1301,20 +1302,26 @@ class LoggedIO:
             self.fds[segment] = (now, fd)
             return fd
 
+        def clean_old():
+            # we regularly get rid of all old FDs here:
+            if now - self._fds_cleaned > FD_MAX_AGE // 8:
+                self._fds_cleaned = now
+                for k, ts_fd in list(self.fds.items()):
+                    ts, fd = ts_fd
+                    if now - ts > FD_MAX_AGE:
+                        # we do not want to touch long-unused file handles to
+                        # avoid ESTALE issues (e.g. on network filesystems).
+                        del self.fds[k]
+
+        clean_old()
         try:
             ts, fd = self.fds[segment]
         except KeyError:
             fd = open_fd()
         else:
-            if now - ts > FD_MAX_AGE:
-                # we do not want to touch long-unused file handles to
-                # avoid ESTALE issues (e.g. on network filesystems).
-                del self.fds[segment]
-                fd = open_fd()
-            else:
-                # fd is fresh enough, so we use it.
-                # also, we update the timestamp of the lru cache entry.
-                self.fds.upd(segment, (now, fd))
+            # we only have fresh enough stuff here.
+            # update the timestamp of the lru cache entry.
+            self.fds.upd(segment, (now, fd))
         return fd
 
     def close_segment(self):