nfs4: Fix minor private cache issues

* Allow Inode::LookUp to handle the case in which the inode number in
  a DirectoryCache entry has no corresponding entry in the InoIdMap.
  This situation can occur after an unused node is freed (due to low
  system resources), since ~VnodeToInode will remove the node's
  InoIdMap entry.
* When a file is overwritten by a rename operation, remove the
  overwritten file's entry from the parent DirectoryCache (although a
  file with this name is still present in the directory, the old
  DirectoryCache entry is now invalid because the name is now linked
  to a different inode).
* Invalidate the cached stat info, including the number of links, in
  Inode::fMetaCache when linking to that inode.
* Make a correction to the assert added in
  https://review.haiku-os.org/c/haiku/+/9282. Entries may still be
  left in this client's InoIdMap if the file was deleted by another
  client.

Change-Id: Id437be32e51a4b324eb818b398d7facd23b7be56
Reviewed-on: https://review.haiku-os.org/c/haiku/+/9308
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: waddlesplash <[email protected]>

src/add-ons/kernel/file_systems/nfs4/Inode.cpp

@@ -212,15 +212,15 @@ Inode::LookUp(const char* name, ino_t* id)
 			entry = entriesList.GetNext(entry);
 		}
 		if (entry != NULL) {
-			// we are skipping ChildAdded(); verify that it is not needed because the InoIdMap
-			// already has this entry
+			// Verify that the InoIdMap already has an entry for this inode.
+			// If not, we need to get the file handle from the server and call ChildAdded().
 			FileInfo info;
 			result = fFileSystem->InoIdMap()->GetFileInfo(&info, entry->fNode);
-			ASSERT(result == B_OK);
-
-			*id = entry->fNode;
-			fCache->Unlock();
-			return B_OK;
+			if (result == B_OK) {
+				*id = entry->fNode;
+				fCache->Unlock();
+				return B_OK;
+			}
 		}
 	}
 	fCache->Unlock();
@@ -265,6 +265,7 @@ Inode::Link(Inode* dir, const char* name)
 
 	fFileSystem->Root()->MakeInfoInvalid();
 	fInfo.fNames->AddName(dir->fInfo.fNames, name);
+	fMetaCache.InvalidateStat();
 
 	dir->fCache->Lock();
 	if (dir->fCache->Valid()) {
@@ -385,7 +386,24 @@ Inode::Rename(Inode* from, Inode* to, const char* fromName, const char* toName,
 	if (oldID != NULL)
 		*oldID = FileIdToInoT(oldFileID);
 
-	DirectoryCache* cache = attribute ? from->fAttrCache : from->fCache;
+	DirectoryCache* cache = NULL;
+	if (*oldID != 0) {
+		// If we overwrote an existing file, remove the DirectoryCache entry of
+		// the overwritten file, which now contains an incorrect inode value.
+		cache = attribute ? to->fAttrCache : to->fCache;
+		cache->Lock();
+		if (cache->Valid()) {
+			if (toChange.fAtomic
+				&& (cache->ChangeInfo() == toChange.fBefore)) {
+				cache->RemoveEntry(toName);
+			} else {
+				cache->Trash();
+			}
+		}
+		cache->Unlock();
+	}
+
+	cache = attribute ? from->fAttrCache : from->fCache;
 	cache->Lock();
 	if (cache->Valid()) {
 		if (fromChange.fAtomic && cache->ChangeInfo() == fromChange.fBefore) {

src/add-ons/kernel/file_systems/nfs4/kernel_interface.cpp

@@ -341,9 +341,12 @@ nfs4_remove_vnode(fs_volume* volume, fs_vnode* vnode, bool reenter)
 	if (node == fs->Root())
 		return B_OK;
 
-	// Verify that all known names have been unlinked.
-	FileInfo fileInfo;
-	ASSERT(fs->InoIdMap()->GetFileInfo(&fileInfo, vti->ID()) == B_ENTRY_NOT_FOUND);
+	// Unless the file was deleted by someone else, verify that all known names have been
+	// unlinked.
+	if (node->IsStale() == false) {
+		FileInfo fileInfo;
+		ASSERT(fs->InoIdMap()->GetFileInfo(&fileInfo, vti->ID()) == B_ENTRY_NOT_FOUND);
+	}
 
 	delete vti;