librbd/cache/pwl: don't crash if cache file removal fails

The non-ec overload will throw fs::filesystem_error on any error
(e.g. EPERM due to unprivileged "rbd persistent-cache invalidate"
being brought up against a privileged workload).

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
(cherry picked from commit 63197ff7003fa9e595527a7431f9f3f6790f7d57)

diff --git a/src/librbd/cache/pwl/DiscardRequest.cc b/src/librbd/cache/pwl/DiscardRequest.cc
index 9f66e077b1f14ed50d4768ca3251be0f5316e2b4..69f48d243e801a99e427a50e6758ed4c11365d2b 100644 (file)
--- a/src/librbd/cache/pwl/DiscardRequest.cc
+++ b/src/librbd/cache/pwl/DiscardRequest.cc
@@ -72,7 +72,13 @@ void DiscardRequest<I>::delete_image_cache_file() {
   if (m_cache_state->present &&
       !m_cache_state->host.compare(ceph_get_short_hostname()) &&
       fs::exists(m_cache_state->path)) {
-    fs::remove(m_cache_state->path);
+    std::error_code ec;
+    fs::remove(m_cache_state->path, ec);
+    if (ec) {
+      lderr(cct) << "failed to remove persistent cache file: " << ec.message()
+                 << dendl;
+      // not fatal
+    }
   }
 
   remove_image_cache_state();