client: _getattr on quota_root before using in statfs

...so that after someone adjusts the quota settings
on an inode that another client is using as its mount root,
the change is visible immediately on the other client.

Signed-off-by: John Spray <john.spray@redhat.com>

diff --git a/src/client/Client.cc b/src/client/Client.cc
index 386650dfb240b7ea39e33ab6ca25d0827c6fdc7d..ccdd5c34f3fab510e1fbb623fa3e41d4560a20b2 100644 (file)
--- a/src/client/Client.cc
+++ b/src/client/Client.cc
@@ -2110,6 +2110,19 @@ void Client::handle_client_session(MClientSession *m)
   m->put();
 }
 
+bool Client::_any_stale_sessions() const
+{
+  assert(client_lock.is_locked_by_me());
+
+  for (const auto &i : mds_sessions) {
+    if (i.second->state == MetaSession::STATE_STALE) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
 void Client::_kick_stale_sessions()
 {
   ldout(cct, 1) << "kick_stale_sessions" << dendl;
@@ -9336,6 +9349,21 @@ int Client::statfs(const char *path, struct statvfs *stbuf,
   assert(cct->_conf->client_quota == false || quota_root != nullptr);
 
   if (quota_root && cct->_conf->client_quota_df && quota_root->quota.max_bytes) {
+
+    // Skip the getattr if any sessions are stale, as we don't want to
+    // block `df` if this client has e.g. been evicted, or if the MDS cluster
+    // is unhealthy.
+    if (!_any_stale_sessions()) {
+      int r = _getattr(quota_root, 0, perms, true);
+      if (r != 0) {
+        // Ignore return value: error getting latest inode metadata is not a good
+        // reason to break "df".
+        lderr(cct) << "Error in getattr on quota root 0x"
+                   << std::hex << quota_root->ino << std::dec
+                   << " statfs result may be outdated" << dendl;
+      }
+    }
+
     // Special case: if there is a size quota set on the Inode acting
     // as the root for this client mount, then report the quota status
     // as the filesystem statistics.

diff --git a/src/client/Client.h b/src/client/Client.h
index 412c00d419d6b89282ea252d450b7054c5d17b2a..236ca90d995e0cb4f0e2a5af572be512e575a775 100644 (file)
--- a/src/client/Client.h
+++ b/src/client/Client.h
@@ -339,6 +339,7 @@ protected:
   MetaSession *_open_mds_session(mds_rank_t mds);
   void _close_mds_session(MetaSession *s);
   void _closed_mds_session(MetaSession *s);
+  bool _any_stale_sessions() const;
   void _kick_stale_sessions();
   void handle_client_session(MClientSession *m);
   void send_reconnect(MetaSession *s);