[llvm] [FileSystem] Allow exclusive file lock (PR #114098)

[Steven Wu via llvm-commits]

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@@ -583,10 +583,14 @@ TEST_F(ProgramEnvTest, TestLockFileExclusive) {
     int FD2;
     ASSERT_NO_ERROR(fs::openFileForReadWrite(LockedFile, FD2,
                                              fs::CD_OpenExisting, fs::OF_None));
+    // File should be non-exclusive locked. Try acquire exclusive lock will fail
+    // but non-exclusive will succeed.
+    EXPECT_TRUE(
+        fs::tryLockFile(FD2, std::chrono::seconds(0), /*Exclusive=*/true));
+
+    EXPECT_FALSE(
+        fs::tryLockFile(FD2, std::chrono::seconds(0), /*Exclusive=*/false));
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cachemeifyoucan wrote:

I think the comment is correct. Exclusive fail first and non-exclusive succeed second. I think the confusion is the first sentence, which should actually states `file is currently non-exclusively locked by other processes`.

https://github.com/llvm/llvm-project/pull/114098