From 27dd88bf9e404411b461a0a36a8219df2ec06867 Mon Sep 17 00:00:00 2001
From: Sebastian Stenzel <sebastian.stenzel@skymatic.de>
Date: Wed, 14 Apr 2021 09:55:52 +0000
Subject: [PATCH] 8262957: (fs) Fail fast in
 UnixFileStore.isExtendedAttributesEnabled

Reviewed-by: alanb
---
 .../unix/classes/sun/nio/fs/UnixFileStore.java       |  5 +++++
 .../classes/sun/nio/fs/UnixNativeDispatcher.java     | 12 ++++++++++--
 .../unix/native/libnio/fs/UnixNativeDispatcher.c     |  6 ++++++
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/src/java.base/unix/classes/sun/nio/fs/UnixFileStore.java b/src/java.base/unix/classes/sun/nio/fs/UnixFileStore.java
index 45d6114ae5f..749d6ff4473 100644
--- a/src/java.base/unix/classes/sun/nio/fs/UnixFileStore.java
+++ b/src/java.base/unix/classes/sun/nio/fs/UnixFileStore.java
@@ -179,6 +179,11 @@ abstract class UnixFileStore
      * @return <code>true</code> if enabled, <code>false</code> if disabled or unable to determine
      */
     protected boolean isExtendedAttributesEnabled(UnixPath path) {
+        if (!UnixNativeDispatcher.xattrSupported()) {
+            // avoid I/O if native code doesn't support xattr
+            return false;
+        }
+
         int fd = -1;
         try {
             fd = path.openForAttributeAccess(false);
diff --git a/src/java.base/unix/classes/sun/nio/fs/UnixNativeDispatcher.java b/src/java.base/unix/classes/sun/nio/fs/UnixNativeDispatcher.java
index 1b0c4ef35cf..90be5cefae3 100644
--- a/src/java.base/unix/classes/sun/nio/fs/UnixNativeDispatcher.java
+++ b/src/java.base/unix/classes/sun/nio/fs/UnixNativeDispatcher.java
@@ -614,8 +614,9 @@ class UnixNativeDispatcher {
      */
     private static final int SUPPORTS_OPENAT        = 1 << 1;  // syscalls
     private static final int SUPPORTS_FUTIMES       = 1 << 2;
-    private static final int SUPPORTS_FUTIMENS      = 1 << 4;
-    private static final int SUPPORTS_LUTIMES       = 1 << 8;
+    private static final int SUPPORTS_FUTIMENS      = 1 << 3;
+    private static final int SUPPORTS_LUTIMES       = 1 << 4;
+    private static final int SUPPORTS_XATTR         = 1 << 5;
     private static final int SUPPORTS_BIRTHTIME     = 1 << 16; // other features
     private static final int capabilities;
 
@@ -654,6 +655,13 @@ class UnixNativeDispatcher {
         return (capabilities & SUPPORTS_BIRTHTIME) != 0;
     }
 
+    /**
+     * Supports extended attributes
+     */
+    static boolean xattrSupported() {
+        return (capabilities & SUPPORTS_XATTR) != 0;
+    }
+
     private static native int init();
     static {
         jdk.internal.loader.BootLoader.loadLibrary("nio");
diff --git a/src/java.base/unix/native/libnio/fs/UnixNativeDispatcher.c b/src/java.base/unix/native/libnio/fs/UnixNativeDispatcher.c
index fe742842f94..9df8be1e62c 100644
--- a/src/java.base/unix/native/libnio/fs/UnixNativeDispatcher.c
+++ b/src/java.base/unix/native/libnio/fs/UnixNativeDispatcher.c
@@ -315,6 +315,12 @@ Java_sun_nio_fs_UnixNativeDispatcher_init(JNIEnv* env, jclass this)
     capabilities |= sun_nio_fs_UnixNativeDispatcher_SUPPORTS_BIRTHTIME;
 #endif
 
+    /* supports extended attributes */
+
+#ifdef _SYS_XATTR_H_
+    capabilities |= sun_nio_fs_UnixNativeDispatcher_SUPPORTS_XATTR;
+#endif
+
     return capabilities;
 }