Fix missing QuotaPath.unwrap() instances (#67165)

Closes #67164. There were a couple of places in
`QuotaAwareFileSystemProvider` where the supplied paths were not being
unwrapped back into platform-specific path objects.

Author: pugnascotia

x-pack/quota-aware-fs/src/main/java/org/elasticsearch/fs/quotaaware/QuotaAwareFileSystemProvider.java

@@ -408,12 +408,12 @@ public void close() throws IOException {
 
     @Override
     public void createLink(Path link, Path existing) throws IOException {
-        delegate.createLink(link, existing);
+        delegate.createLink(QuotaAwarePath.unwrap(link), QuotaAwarePath.unwrap(existing));
     }
 
     @Override
     public void createSymbolicLink(Path link, Path target, FileAttribute<?>... attrs) throws IOException {
-        delegate.createSymbolicLink(link, target, attrs);
+        delegate.createSymbolicLink(QuotaAwarePath.unwrap(link), QuotaAwarePath.unwrap(target), attrs);
     }
 
     void purge(FileSystem delegateFileSystem) {

x-pack/quota-aware-fs/src/test/java/org/elasticsearch/fs/quotaaware/QuotaAwareFileSystemProviderTests.java

@@ -20,8 +20,10 @@
 import java.nio.charset.StandardCharsets;
 import java.nio.file.FileStore;
 import java.nio.file.FileSystems;
+import java.nio.file.Files;
 import java.nio.file.NoSuchFileException;
 import java.nio.file.Path;
+import java.nio.file.attribute.FileAttribute;
 import java.nio.file.spi.FileSystemProvider;
 import java.security.PrivilegedActionException;
 import java.util.Properties;
@@ -279,6 +281,48 @@ public Path getPath(URI uri) {
         }
     }
 
+    /**
+     * If the implementation of {@link QuotaAwareFileSystemProvider#createLink(Path, Path)}
+     * doesn't unwrap its {@link Path} arguments, it causes a runtime exception, so exercise
+     * this method to check that it unwraps correctly.
+     */
+    public void testCreateLinkUnwrapsPaths() throws Exception {
+        final Path tempDir = createTempDir();
+        Path quotaFile = tempDir.resolve("quota.properties");
+        FileSystemProvider systemProvider = quotaFile.getFileSystem().provider();
+        writeQuota(500, 200, systemProvider, quotaFile);
+
+        try (QuotaAwareFileSystemProvider provider = new QuotaAwareFileSystemProvider(systemProvider, quotaFile.toUri())) {
+            final Path quotaFilePath = provider.getPath(tempDir.resolve("path1.txt").toUri());
+            final Path quotaLinkPath = provider.getPath(tempDir.resolve("path2.txt").toUri());
+
+            Files.write(quotaFilePath, "some text".getBytes(StandardCharsets.UTF_8));
+
+            provider.createLink(quotaLinkPath, quotaFilePath);
+        }
+    }
+
+    /**
+     * If the implementation of {@link QuotaAwareFileSystemProvider#createSymbolicLink(Path, Path, FileAttribute[])}
+     * doesn't unwrap its {@link Path} arguments, it causes a runtime exception, so exercise
+     * this method to check that it unwraps correctly.
+     */
+    public void testCreateSymbolicLinkUnwrapsPaths() throws Exception {
+        final Path tempDir = createTempDir();
+        Path quotaFile = tempDir.resolve("quota.properties");
+        FileSystemProvider systemProvider = quotaFile.getFileSystem().provider();
+        writeQuota(500, 200, systemProvider, quotaFile);
+
+        try (QuotaAwareFileSystemProvider provider = new QuotaAwareFileSystemProvider(systemProvider, quotaFile.toUri())) {
+            final Path quotaFilePath = provider.getPath(tempDir.resolve("path1.txt").toUri());
+            final Path quotaLinkPath = provider.getPath(tempDir.resolve("path2.txt").toUri());
+
+            Files.write(quotaFilePath, "some text".getBytes(StandardCharsets.UTF_8));
+
+            provider.createSymbolicLink(quotaLinkPath, quotaFilePath);
+        }
+    }
+
     private void doValidFileTest(long expectedTotal, long expectedRemaining) throws Exception {
         Path quotaFile = createTempDir().resolve("quota.properties");
         FileSystemProvider systemProvider = quotaFile.getFileSystem().provider();