Merge PR ceph#51417 into main

* refs/pull/51417/head:
	client: only wait for write MDS OPs when unmounting
	client: flush the mdlog before waiting for unsafe requests

Reviewed-by: Venky Shankar <[email protected]>
Reviewed-by: Dhairya Parmar <[email protected]>
Reviewed-by: Patrick Donnelly <[email protected]>

Author: vshankar

src/client/Client.cc

@@ -6673,11 +6673,18 @@ void Client::_unmount(bool abort)
   }
 
   mount_cond.wait(lock, [this] {
-    if (!mds_requests.empty()) {
-      ldout(cct, 10) << "waiting on " << mds_requests.size() << " requests"
-		     << dendl;
+    // Only wait for write OPs
+    for (auto& [tid, req] : mds_requests) {
+      if (req->is_write()) {
+        ldout(cct, 10) << "waiting for write request '" << tid
+                       << "' to complete, currently there are "
+                       << mds_requests.size()
+                       << " outstanding read/write requests"
+                       << dendl;
+        return false;
+      }
     }
-    return mds_requests.empty();
+    return true;
   });
 
   cwd.reset();
@@ -6690,7 +6697,7 @@ void Client::_unmount(bool abort)
     ldout(cct, 0) << " destroyed lost open file " << fh << " on " << *fh->inode << dendl;
     _release_fh(fh);
   }
-  
+
   while (!ll_unclosed_fh_set.empty()) {
     set<Fh*>::iterator it = ll_unclosed_fh_set.begin();
     Fh *fh = *it;
@@ -11964,6 +11971,9 @@ int Client::_sync_fs()
   flush_caps_sync();
   ceph_tid_t flush_tid = last_flush_tid;
 
+  // flush the mdlog before waiting for unsafe requests.
+  flush_mdlog_sync();
+
   // wait for unsafe mds requests
   wait_unsafe_requests();