Disambiguate fs2 extension-trait locking calls

Summary:
Some `fs2::FileExt` extension-trait methods overlap with new file locking API on `std::fs::File` in Rust 1.84 (D70601924).

```lang=text,counterexample
error: a method with this name may be added to the standard library in the future
   --> fbcode/clifoundation/cli_target/validator/src/main.rs:279:20
    |
279 |         cache_file.lock_shared()?;
    |                    ^^^^^^^^^^^
    |
    = warning: once this associated item is added to the standard library, the ambiguity may cause an error or change in behavior!
    = note: for more information, see issue #48919 <rust-lang/rust#48919>
    = help: call with fully qualified syntax `fs4::FileExt::lock_shared(...)` to keep using the current method
    = note: requested on the command line with `-D unstable-name-collisions`
help: add `#![feature(file_lock)]` to the crate attributes to enable `std::fs::File::lock_shared`
    |
1   + #![feature(file_lock)]
    |
```

This diff (still on Rust 1.83) qualifies all the extension-trait calls so that these do not become a factor in the Rust 1.84 diff.

After D70601924, it would be reasonable to drop `fs2` and `fs4` dependencies and use the standard library APIs instead.

Reviewed By: diliop

Differential Revision: D70676686

fbshipit-source-id: ed9dc8fa139c56e1a6f8e2fc39b923a81e8711b3

Author: David Tolnay

app/buck2_client_ctx/src/daemon/client.rs

@@ -23,7 +23,6 @@ use buck2_core::fs::paths::abs_norm_path::AbsNormPathBuf;
 use buck2_data::error::ErrorTag;
 use buck2_error::BuckErrorContext;
 use buck2_event_log::stream_value::StreamValue;
-use fs4::FileExt;
 use futures::future::BoxFuture;
 use futures::pin_mut;
 use futures::stream;
@@ -94,7 +93,7 @@ impl BuckdLifecycleLock {
                 "locking buckd lifecycle",
                 Duration::from_millis(5),
                 Duration::from_millis(100),
-                || async { Ok(fileref.try_lock_exclusive()?) },
+                || async { Ok(fs4::FileExt::try_lock_exclusive(fileref)?) },
             )
             .await?;
 
@@ -129,8 +128,7 @@ impl BuckdLifecycleLock {
 
 impl Drop for BuckdLifecycleLock {
     fn drop(&mut self) {
-        self.lock_file
-            .unlock()
+        fs4::FileExt::unlock(&self.lock_file)
             .expect("Unexpected failure to unlock buckd.lifecycle file.")
     }
 }

app/buck2_common/src/build_count.rs

@@ -15,7 +15,6 @@ use buck2_core::fs::paths::abs_norm_path::AbsNormPathBuf;
 use buck2_core::fs::paths::file_name::FileName;
 use buck2_data::ParsedTargetPatterns;
 use buck2_error::BuckErrorContext;
-use fs4::FileExt;
 use serde::Deserialize;
 use serde::Serialize;
 
@@ -135,7 +134,7 @@ impl BuildCountManager {
             Duration::from_millis(5),
             Duration::from_millis(100),
             timeout,
-            || async { buck2_error::Ok(fileref.try_lock_exclusive()?) },
+            || async { buck2_error::Ok(fs4::FileExt::try_lock_exclusive(fileref)?) },
         )
         .await?;
         Ok(FileLockGuard { file })
@@ -193,8 +192,7 @@ struct FileLockGuard {
 
 impl Drop for FileLockGuard {
     fn drop(&mut self) {
-        self.file
-            .unlock()
+        fs4::FileExt::unlock(&self.file)
             .expect("Unexpected failure to release a lock file for build count");
     }
 }