mv: improve the hardlink support (#8296)

* mv: implement hardlink support

Should fix GNU tests/mv/part-hardlink.sh tests/mv/hard-link-1.sh

Co-authored-by: Daniel Hofstetter <daniel.hofstetter@42dh.com>

* mv: fix the GNU test - tests/mv/part-fail

* make it pass on windows

---------

Co-authored-by: Daniel Hofstetter <daniel.hofstetter@42dh.com>

src/uu/mv/src/hardlink.rs

@@ -0,0 +1,346 @@
+// This file is part of the uutils coreutils package.
+//
+// For the full copyright and license information, please view the LICENSE
+// file that was distributed with this source code.
+// spell-checker:ignore hardlinked
+
+//! Hardlink preservation utilities for mv operations
+//!
+//! This module provides functionality to preserve hardlink relationships
+//! when moving files across different filesystems/partitions.
+
+use std::collections::HashMap;
+use std::io;
+use std::path::{Path, PathBuf};
+
+/// Tracks hardlinks during cross-partition moves to preserve them
+#[derive(Debug, Default)]
+pub struct HardlinkTracker {
+    /// Maps (device, inode) -> destination path for the first occurrence
+    inode_map: HashMap<(u64, u64), PathBuf>,
+}
+
+/// Pre-scans files to identify hardlink groups with optimized memory usage
+#[derive(Debug, Default)]
+pub struct HardlinkGroupScanner {
+    /// Maps (device, inode) -> list of source paths that are hardlinked together
+    hardlink_groups: HashMap<(u64, u64), Vec<PathBuf>>,
+    /// List of source files/directories being moved (for destination mapping)
+    source_files: Vec<PathBuf>,
+    /// Whether scanning has been performed
+    scanned: bool,
+}
+
+/// Configuration options for hardlink preservation
+#[derive(Debug, Clone, Default)]
+pub struct HardlinkOptions {
+    /// Whether to show verbose output about hardlink operations
+    pub verbose: bool,
+}
+
+/// Result type for hardlink operations
+pub type HardlinkResult<T> = Result<T, HardlinkError>;
+
+/// Errors that can occur during hardlink operations
+#[derive(Debug)]
+pub enum HardlinkError {
+    Io(io::Error),
+    Scan(String),
+    Preservation { source: PathBuf, target: PathBuf },
+    Metadata { path: PathBuf, error: io::Error },
+}
+
+impl std::fmt::Display for HardlinkError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            HardlinkError::Io(e) => write!(f, "I/O error during hardlink operation: {}", e),
+            HardlinkError::Scan(msg) => {
+                write!(f, "Failed to scan files for hardlinks: {}", msg)
+            }
+            HardlinkError::Preservation { source, target } => {
+                write!(
+                    f,
+                    "Failed to preserve hardlink: {} -> {}",
+                    source.display(),
+                    target.display()
+                )
+            }
+            HardlinkError::Metadata { path, error } => {
+                write!(f, "Metadata access error for {}: {}", path.display(), error)
+            }
+        }
+    }
+}
+
+impl std::error::Error for HardlinkError {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        match self {
+            HardlinkError::Io(e) => Some(e),
+            HardlinkError::Metadata { error, .. } => Some(error),
+            _ => None,
+        }
+    }
+}
+
+impl From<io::Error> for HardlinkError {
+    fn from(error: io::Error) -> Self {
+        HardlinkError::Io(error)
+    }
+}
+
+impl From<HardlinkError> for io::Error {
+    fn from(error: HardlinkError) -> Self {
+        match error {
+            HardlinkError::Io(e) => e,
+            HardlinkError::Scan(msg) => io::Error::other(msg),
+            HardlinkError::Preservation { source, target } => io::Error::other(format!(
+                "Failed to preserve hardlink: {} -> {}",
+                source.display(),
+                target.display()
+            )),
+
+            HardlinkError::Metadata { path, error } => io::Error::other(format!(
+                "Metadata access error for {}: {}",
+                path.display(),
+                error
+            )),
+        }
+    }
+}
+
+impl HardlinkTracker {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Check if a file is a hardlink we've seen before, and return the target path if so
+    pub fn check_hardlink(
+        &mut self,
+        source: &Path,
+        dest: &Path,
+        scanner: &HardlinkGroupScanner,
+        options: &HardlinkOptions,
+    ) -> HardlinkResult<Option<PathBuf>> {
+        use std::os::unix::fs::MetadataExt;
+
+        let metadata = match source.metadata() {
+            Ok(meta) => meta,
+            Err(e) => {
+                // Gracefully handle metadata errors by logging and continuing without hardlink tracking
+                if options.verbose {
+                    eprintln!(
+                        "warning: cannot get metadata for {}: {}",
+                        source.display(),
+                        e
+                    );
+                }
+                return Ok(None);
+            }
+        };
+
+        let key = (metadata.dev(), metadata.ino());
+
+        // Check if we've already processed a file with this inode
+        if let Some(existing_path) = self.inode_map.get(&key) {
+            // Check if this file is part of a hardlink group from the scanner
+            let has_hardlinks = scanner
+                .hardlink_groups
+                .get(&key)
+                .map(|group| group.len() > 1)
+                .unwrap_or(false);
+
+            if has_hardlinks {
+                if options.verbose {
+                    eprintln!(
+                        "preserving hardlink {} -> {} (hardlinked)",
+                        source.display(),
+                        existing_path.display()
+                    );
+                }
+                return Ok(Some(existing_path.clone()));
+            }
+        }
+
+        // This is the first time we see this file, record its destination
+        self.inode_map.insert(key, dest.to_path_buf());
+
+        Ok(None)
+    }
+}
+
+impl HardlinkGroupScanner {
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Scan files and group them by hardlinks, including recursive directory scanning
+    pub fn scan_files(
+        &mut self,
+        files: &[PathBuf],
+        options: &HardlinkOptions,
+    ) -> HardlinkResult<()> {
+        if self.scanned {
+            return Ok(());
+        }
+
+        // Store the source files for destination mapping
+        self.source_files = files.to_vec();
+
+        for file in files {
+            if let Err(e) = self.scan_single_path(file) {
+                if options.verbose {
+                    // Only show warnings for verbose mode
+                    eprintln!("warning: failed to scan {}: {}", file.display(), e);
+                }
+                // For non-verbose mode, silently continue for missing files
+                // This provides graceful degradation - we'll lose hardlink info for this file
+                // but can still preserve hardlinks for other files
+                continue;
+            }
+        }
+
+        self.scanned = true;
+
+        if options.verbose {
+            let stats = self.stats();
+            if stats.total_groups > 0 {
+                eprintln!(
+                    "found {} hardlink groups with {} total files",
+                    stats.total_groups, stats.total_files
+                );
+            }
+        }
+
+        Ok(())
+    }
+
+    /// Scan a single path (file or directory)
+    fn scan_single_path(&mut self, path: &Path) -> io::Result<()> {
+        use std::os::unix::fs::MetadataExt;
+
+        if path.is_dir() {
+            // Recursively scan directory contents
+            self.scan_directory_recursive(path)?;
+        } else {
+            let metadata = path.metadata()?;
+            if metadata.nlink() > 1 {
+                let key = (metadata.dev(), metadata.ino());
+                self.hardlink_groups
+                    .entry(key)
+                    .or_default()
+                    .push(path.to_path_buf());
+            }
+        }
+        Ok(())
+    }
+
+    /// Recursively scan a directory for hardlinked files
+    fn scan_directory_recursive(&mut self, dir: &Path) -> io::Result<()> {
+        use std::os::unix::fs::MetadataExt;
+
+        let entries = std::fs::read_dir(dir)?;
+        for entry in entries {
+            let entry = entry?;
+            let path = entry.path();
+
+            if path.is_dir() {
+                self.scan_directory_recursive(&path)?;
+            } else {
+                let metadata = path.metadata()?;
+                if metadata.nlink() > 1 {
+                    let key = (metadata.dev(), metadata.ino());
+                    self.hardlink_groups.entry(key).or_default().push(path);
+                }
+            }
+        }
+        Ok(())
+    }
+
+    #[cfg(not(unix))]
+    pub fn scan_files(
+        &mut self,
+        files: &[PathBuf],
+        _options: &HardlinkOptions,
+    ) -> HardlinkResult<()> {
+        self.source_files = files.to_vec();
+        self.scanned = true;
+        Ok(())
+    }
+
+    #[cfg(not(unix))]
+    pub fn stats(&self) -> ScannerStats {
+        ScannerStats {
+            total_groups: 0,
+            total_files: 0,
+        }
+    }
+
+    /// Get statistics about scanned hardlinks
+    #[cfg(unix)]
+    pub fn stats(&self) -> ScannerStats {
+        let total_groups = self.hardlink_groups.len();
+        let total_files = self.hardlink_groups.values().map(|group| group.len()).sum();
+
+        ScannerStats {
+            total_groups,
+            total_files,
+        }
+    }
+}
+
+/// Statistics about hardlink scanning
+#[derive(Debug, Clone)]
+pub struct ScannerStats {
+    pub total_groups: usize,
+    pub total_files: usize,
+}
+
+/// Create a new hardlink tracker and scanner pair
+pub fn create_hardlink_context() -> (HardlinkTracker, HardlinkGroupScanner) {
+    (HardlinkTracker::new(), HardlinkGroupScanner::new())
+}
+
+/// Convenient function to execute operations with proper hardlink context handling
+pub fn with_optional_hardlink_context<F, R>(
+    tracker: Option<&mut HardlinkTracker>,
+    scanner: Option<&HardlinkGroupScanner>,
+    operation: F,
+) -> R
+where
+    F: FnOnce(&mut HardlinkTracker, &HardlinkGroupScanner) -> R,
+{
+    match (tracker, scanner) {
+        (Some(tracker), Some(scanner)) => operation(tracker, scanner),
+        _ => {
+            let (mut dummy_tracker, dummy_scanner) = create_hardlink_context();
+            operation(&mut dummy_tracker, &dummy_scanner)
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_hardlink_tracker_creation() {
+        let _tracker = HardlinkTracker::new();
+        // Just test that creation works
+    }
+
+    #[test]
+    fn test_scanner_creation() {
+        let scanner = HardlinkGroupScanner::new();
+        let stats = scanner.stats();
+        assert_eq!(stats.total_groups, 0);
+        assert_eq!(stats.total_files, 0);
+    }
+
+    #[test]
+    fn test_create_hardlink_context() {
+        let (_tracker, scanner) = create_hardlink_context();
+        let stats = scanner.stats();
+        assert_eq!(stats.total_groups, 0);
+        assert_eq!(stats.total_files, 0);
+    }
+}

src/uu/mv/src/mv.rs

@@ -6,6 +6,8 @@
 // spell-checker:ignore (ToDO) sourcepath targetpath nushell canonicalized
 
 mod error;
+#[cfg(unix)]
+mod hardlink;
 
 use clap::builder::ValueParser;
 use clap::{Arg, ArgAction, ArgMatches, Command, error::ErrorKind};
@@ -24,6 +26,11 @@ use std::os::unix::fs::FileTypeExt;
 use std::os::windows;
 use std::path::{Path, PathBuf, absolute};
 
+#[cfg(unix)]
+use crate::hardlink::{
+    HardlinkGroupScanner, HardlinkOptions, HardlinkTracker, create_hardlink_context,
+    with_optional_hardlink_context,
+};
 use uucore::backup_control::{self, source_is_target_backup};
 use uucore::display::Quotable;
 use uucore::error::{FromIo, UResult, USimpleError, UUsageError, set_exit_code};
@@ -42,10 +49,7 @@ use uucore::update_control;
 pub use uucore::{backup_control::BackupMode, update_control::UpdateMode};
 use uucore::{format_usage, prompt_yes, show};
 
-use fs_extra::dir::{
-    CopyOptions as DirCopyOptions, TransitProcess, TransitProcessResult, get_size as dir_get_size,
-    move_dir, move_dir_with_progress,
-};
+use fs_extra::dir::get_size as dir_get_size;
 
 use crate::error::MvError;
 use uucore::locale::{get_message, get_message_with_args};
@@ -357,7 +361,22 @@ fn handle_two_paths(source: &Path, target: &Path, opts: &Options) -> UResult<()>
     if target_is_dir {
         if opts.no_target_dir {
             if source.is_dir() {
-                rename(source, target, opts, None).map_err_context(|| {
+                #[cfg(unix)]
+                let (mut hardlink_tracker, hardlink_scanner) = create_hardlink_context();
+                #[cfg(unix)]
+                let hardlink_params = (Some(&mut hardlink_tracker), Some(&hardlink_scanner));
+                #[cfg(not(unix))]
+                let hardlink_params = (None, None);
+
+                rename(
+                    source,
+                    target,
+                    opts,
+                    None,
+                    hardlink_params.0,
+                    hardlink_params.1,
+                )
+                .map_err_context(|| {
                     get_message_with_args(
                         "mv-error-cannot-move",
                         HashMap::from([
@@ -394,7 +413,22 @@ fn handle_two_paths(source: &Path, target: &Path, opts: &Options) -> UResult<()>
         )
         .into())
     } else {
-        rename(source, target, opts, None).map_err(|e| USimpleError::new(1, format!("{e}")))
+        #[cfg(unix)]
+        let (mut hardlink_tracker, hardlink_scanner) = create_hardlink_context();
+        #[cfg(unix)]
+        let hardlink_params = (Some(&mut hardlink_tracker), Some(&hardlink_scanner));
+        #[cfg(not(unix))]
+        let hardlink_params = (None, None);
+
+        rename(
+            source,
+            target,
+            opts,
+            None,
+            hardlink_params.0,
+            hardlink_params.1,
+        )
+        .map_err(|e| USimpleError::new(1, format!("{e}")))
     }
 }
 
@@ -516,6 +550,33 @@ pub fn mv(files: &[OsString], opts: &Options) -> UResult<()> {
 fn move_files_into_dir(files: &[PathBuf], target_dir: &Path, options: &Options) -> UResult<()> {
     // remember the moved destinations for further usage
     let mut moved_destinations: HashSet<PathBuf> = HashSet::with_capacity(files.len());
+    // Create hardlink tracking context
+    #[cfg(unix)]
+    let (mut hardlink_tracker, hardlink_scanner) = {
+        let (tracker, mut scanner) = create_hardlink_context();
+
+        // Use hardlink options
+        let hardlink_options = HardlinkOptions {
+            verbose: options.verbose || options.debug,
+        };
+
+        // Pre-scan files if needed
+        if let Err(e) = scanner.scan_files(files, &hardlink_options) {
+            if hardlink_options.verbose {
+                eprintln!("mv: warning: failed to scan files for hardlinks: {}", e);
+                eprintln!("mv: continuing without hardlink preservation");
+            } else {
+                // Show warning in non-verbose mode for serious errors
+                eprintln!(
+                    "mv: warning: hardlink scanning failed, continuing without hardlink preservation"
+                );
+            }
+            // Continue without hardlink tracking on scan failure
+            // This provides graceful degradation rather than failing completely
+        }
+
+        (tracker, scanner)
+    };
 
     if !target_dir.is_dir() {
         return Err(MvError::NotADirectory(target_dir.quote().to_string()).into());
@@ -550,7 +611,8 @@ fn move_files_into_dir(files: &[PathBuf], target_dir: &Path, options: &Options)
         }
 
         if let Some(ref pb) = count_progress {
-            pb.set_message(sourcepath.to_string_lossy().to_string());
+            let msg = format!("{} (scanning hardlinks)", sourcepath.to_string_lossy());
+            pb.set_message(msg);
         }
 
         let targetpath = match sourcepath.file_name() {
@@ -583,7 +645,19 @@ fn move_files_into_dir(files: &[PathBuf], target_dir: &Path, options: &Options)
             continue;
         }
 
-        match rename(sourcepath, &targetpath, options, multi_progress.as_ref()) {
+        #[cfg(unix)]
+        let hardlink_params = (Some(&mut hardlink_tracker), Some(&hardlink_scanner));
+        #[cfg(not(unix))]
+        let hardlink_params = (None, None);
+
+        match rename(
+            sourcepath,
+            &targetpath,
+            options,
+            multi_progress.as_ref(),
+            hardlink_params.0,
+            hardlink_params.1,
+        ) {
             Err(e) if e.to_string().is_empty() => set_exit_code(1),
             Err(e) => {
                 let e = e.map_err_context(|| {
@@ -615,6 +689,10 @@ fn rename(
     to: &Path,
     opts: &Options,
     multi_progress: Option<&MultiProgress>,
+    #[cfg(unix)] hardlink_tracker: Option<&mut HardlinkTracker>,
+    #[cfg(unix)] hardlink_scanner: Option<&HardlinkGroupScanner>,
+    #[cfg(not(unix))] _hardlink_tracker: Option<()>,
+    #[cfg(not(unix))] _hardlink_scanner: Option<()>,
 ) -> io::Result<()> {
     let mut backup_path = None;
 
@@ -675,7 +753,8 @@ fn rename(
 
         backup_path = backup_control::get_backup_path(opts.backup, to, &opts.suffix);
         if let Some(ref backup_path) = backup_path {
-            rename_with_fallback(to, backup_path, multi_progress)?;
+            // For backup renames, we don't need to track hardlinks as we're just moving the existing file
+            rename_with_fallback(to, backup_path, multi_progress, None, None)?;
         }
     }
 
@@ -693,7 +772,14 @@ fn rename(
         }
     }
 
-    rename_with_fallback(from, to, multi_progress)?;
+    #[cfg(unix)]
+    {
+        rename_with_fallback(from, to, multi_progress, hardlink_tracker, hardlink_scanner)?;
+    }
+    #[cfg(not(unix))]
+    {
+        rename_with_fallback(from, to, multi_progress, None, None)?;
+    }
 
     if opts.verbose {
         let message = match backup_path {
@@ -740,6 +826,10 @@ fn rename_with_fallback(
     from: &Path,
     to: &Path,
     multi_progress: Option<&MultiProgress>,
+    #[cfg(unix)] hardlink_tracker: Option<&mut HardlinkTracker>,
+    #[cfg(unix)] hardlink_scanner: Option<&HardlinkGroupScanner>,
+    #[cfg(not(unix))] _hardlink_tracker: Option<()>,
+    #[cfg(not(unix))] _hardlink_scanner: Option<()>,
 ) -> io::Result<()> {
     fs::rename(from, to).or_else(|err| {
         #[cfg(windows)]
@@ -762,12 +852,36 @@ fn rename_with_fallback(
         if file_type.is_symlink() {
             rename_symlink_fallback(from, to)
         } else if file_type.is_dir() {
+            #[cfg(unix)]
+            {
+                with_optional_hardlink_context(
+                    hardlink_tracker,
+                    hardlink_scanner,
+                    |tracker, scanner| {
+                        rename_dir_fallback(from, to, multi_progress, Some(tracker), Some(scanner))
+                    },
+                )
+            }
+            #[cfg(not(unix))]
+            {
                 rename_dir_fallback(from, to, multi_progress)
+            }
         } else if is_fifo(file_type) {
             rename_fifo_fallback(from, to)
         } else {
+            #[cfg(unix)]
+            {
+                with_optional_hardlink_context(
+                    hardlink_tracker,
+                    hardlink_scanner,
+                    |tracker, scanner| rename_file_fallback(from, to, Some(tracker), Some(scanner)),
+                )
+            }
+            #[cfg(not(unix))]
+            {
                 rename_file_fallback(from, to)
             }
+        }
     })
 }
 
@@ -824,6 +938,8 @@ fn rename_dir_fallback(
     from: &Path,
     to: &Path,
     multi_progress: Option<&MultiProgress>,
+    #[cfg(unix)] hardlink_tracker: Option<&mut HardlinkTracker>,
+    #[cfg(unix)] hardlink_scanner: Option<&HardlinkGroupScanner>,
 ) -> io::Result<()> {
     // We remove the destination directory if it exists to match the
     // behavior of `fs::rename`. As far as I can tell, `fs_extra`'s
@@ -831,13 +947,6 @@ fn rename_dir_fallback(
     if to.exists() {
         fs::remove_dir_all(to)?;
     }
-    let options = DirCopyOptions {
-        // From the `fs_extra` documentation:
-        // "Recursively copy a directory with a new name or place it
-        // inside the destination. (same behaviors like cp -r in Unix)"
-        copy_inside: true,
-        ..DirCopyOptions::new()
-    };
 
     // Calculate total size of directory
     // Silently degrades:
@@ -859,55 +968,194 @@ fn rename_dir_fallback(
     #[cfg(all(unix, not(any(target_os = "macos", target_os = "redox"))))]
     let xattrs = fsxattr::retrieve_xattrs(from).unwrap_or_else(|_| HashMap::new());
 
-    let result = if let Some(ref pb) = progress_bar {
-        move_dir_with_progress(from, to, &options, |process_info: TransitProcess| {
-            pb.set_position(process_info.copied_bytes);
-            pb.set_message(process_info.file_name);
-            TransitProcessResult::ContinueOrAbort
-        })
-    } else {
-        move_dir(from, to, &options)
-    };
+    // Use directory copying (with or without hardlink support)
+    let result = copy_dir_contents(
+        from,
+        to,
+        #[cfg(unix)]
+        hardlink_tracker,
+        #[cfg(unix)]
+        hardlink_scanner,
+        progress_bar.as_ref(),
+    );
 
     #[cfg(all(unix, not(any(target_os = "macos", target_os = "redox"))))]
     fsxattr::apply_xattrs(to, xattrs)?;
 
-    match result {
-        Err(err) => match err.kind {
-            fs_extra::error::ErrorKind::PermissionDenied => Err(io::Error::new(
-                io::ErrorKind::PermissionDenied,
-                get_message("mv-error-permission-denied"),
-            )),
-            _ => Err(io::Error::other(format!("{err:?}"))),
-        },
-        _ => Ok(()),
+    result?;
+
+    // Remove the source directory after successful copy
+    fs::remove_dir_all(from)?;
+
+    Ok(())
+}
+
+/// Copy directory recursively, optionally preserving hardlinks
+fn copy_dir_contents(
+    from: &Path,
+    to: &Path,
+    #[cfg(unix)] hardlink_tracker: Option<&mut HardlinkTracker>,
+    #[cfg(unix)] hardlink_scanner: Option<&HardlinkGroupScanner>,
+    progress_bar: Option<&ProgressBar>,
+) -> io::Result<()> {
+    // Create the destination directory
+    fs::create_dir_all(to)?;
+
+    // Recursively copy contents
+    #[cfg(unix)]
+    {
+        if let (Some(tracker), Some(scanner)) = (hardlink_tracker, hardlink_scanner) {
+            copy_dir_contents_recursive(from, to, tracker, scanner, progress_bar)?;
+        }
+    }
+    #[cfg(not(unix))]
+    {
+        copy_dir_contents_recursive(from, to, progress_bar)?;
+    }
+
+    Ok(())
+}
+
+fn copy_dir_contents_recursive(
+    from_dir: &Path,
+    to_dir: &Path,
+    #[cfg(unix)] hardlink_tracker: &mut HardlinkTracker,
+    #[cfg(unix)] hardlink_scanner: &HardlinkGroupScanner,
+    progress_bar: Option<&ProgressBar>,
+) -> io::Result<()> {
+    let entries = fs::read_dir(from_dir)?;
+
+    for entry in entries {
+        let entry = entry?;
+        let from_path = entry.path();
+        let file_name = from_path.file_name().unwrap();
+        let to_path = to_dir.join(file_name);
+
+        if let Some(pb) = progress_bar {
+            pb.set_message(from_path.to_string_lossy().to_string());
+        }
+
+        if from_path.is_dir() {
+            // Recursively copy subdirectory
+            fs::create_dir_all(&to_path)?;
+            copy_dir_contents_recursive(
+                &from_path,
+                &to_path,
+                #[cfg(unix)]
+                hardlink_tracker,
+                #[cfg(unix)]
+                hardlink_scanner,
+                progress_bar,
+            )?;
+        } else {
+            // Copy file with or without hardlink support based on platform
+            #[cfg(unix)]
+            {
+                copy_file_with_hardlinks_helper(
+                    &from_path,
+                    &to_path,
+                    hardlink_tracker,
+                    hardlink_scanner,
+                )?;
+            }
+            #[cfg(not(unix))]
+            {
+                fs::copy(&from_path, &to_path)?;
             }
         }
 
-fn rename_file_fallback(from: &Path, to: &Path) -> io::Result<()> {
+        if let Some(pb) = progress_bar {
+            if let Ok(metadata) = from_path.metadata() {
+                pb.inc(metadata.len());
+            }
+        }
+    }
+
+    Ok(())
+}
+
+#[cfg(unix)]
+fn copy_file_with_hardlinks_helper(
+    from: &Path,
+    to: &Path,
+    hardlink_tracker: &mut HardlinkTracker,
+    hardlink_scanner: &HardlinkGroupScanner,
+) -> io::Result<()> {
+    // Check if this file should be a hardlink to an already-copied file
+    use crate::hardlink::HardlinkOptions;
+    let hardlink_options = HardlinkOptions::default();
+    // Create a hardlink instead of copying
+    if let Some(existing_target) =
+        hardlink_tracker.check_hardlink(from, to, hardlink_scanner, &hardlink_options)?
+    {
+        fs::hard_link(&existing_target, to)?;
+        return Ok(());
+    }
+
+    // Regular file copy
+    #[cfg(all(unix, not(any(target_os = "macos", target_os = "redox"))))]
+    {
+        fs::copy(from, to).and_then(|_| fsxattr::copy_xattrs(&from, &to))?;
+    }
+    #[cfg(any(target_os = "macos", target_os = "redox"))]
+    {
+        fs::copy(from, to)?;
+    }
+
+    Ok(())
+}
+
+fn rename_file_fallback(
+    from: &Path,
+    to: &Path,
+    #[cfg(unix)] hardlink_tracker: Option<&mut HardlinkTracker>,
+    #[cfg(unix)] hardlink_scanner: Option<&HardlinkGroupScanner>,
+) -> io::Result<()> {
+    // Remove existing target file if it exists
     if to.is_symlink() {
         fs::remove_file(to).map_err(|err| {
-            let to = to.to_string_lossy();
-            let from = from.to_string_lossy();
-            io::Error::new(
-                err.kind(),
-                get_message_with_args(
+            let inter_device_msg = get_message_with_args(
                 "mv-error-inter-device-move-failed",
                 HashMap::from([
-                        ("from".to_string(), from.to_string()),
-                        ("to".to_string(), to.to_string()),
+                    ("from".to_string(), from.display().to_string()),
+                    ("to".to_string(), to.display().to_string()),
                     ("err".to_string(), err.to_string()),
                 ]),
-                ),
-            )
+            );
+            io::Error::new(err.kind(), inter_device_msg)
         })?;
+    } else if to.exists() {
+        // For non-symlinks, just remove the file without special error handling
+        fs::remove_file(to)?;
     }
+
+    // Check if this file is part of a hardlink group and if so, create a hardlink instead of copying
+    #[cfg(unix)]
+    {
+        if let (Some(tracker), Some(scanner)) = (hardlink_tracker, hardlink_scanner) {
+            use crate::hardlink::HardlinkOptions;
+            let hardlink_options = HardlinkOptions::default();
+            if let Some(existing_target) =
+                tracker.check_hardlink(from, to, scanner, &hardlink_options)?
+            {
+                // Create a hardlink to the first moved file instead of copying
+                fs::hard_link(&existing_target, to)?;
+                fs::remove_file(from)?;
+                return Ok(());
+            }
+        }
+    }
+
+    // Regular file copy
     #[cfg(all(unix, not(any(target_os = "macos", target_os = "redox"))))]
     fs::copy(from, to)
         .and_then(|_| fsxattr::copy_xattrs(&from, &to))
-        .and_then(|_| fs::remove_file(from))?;
+        .and_then(|_| fs::remove_file(from))
+        .map_err(|err| io::Error::new(err.kind(), get_message("mv-error-permission-denied")))?;
     #[cfg(any(target_os = "macos", target_os = "redox", not(unix)))]
-    fs::copy(from, to).and_then(|_| fs::remove_file(from))?;
+    fs::copy(from, to)
+        .and_then(|_| fs::remove_file(from))
+        .map_err(|err| io::Error::new(err.kind(), get_message("mv-error-permission-denied")))?;
     Ok(())
 }
 

tests/by-util/test_mv.rs

@@ -3,7 +3,8 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 //
-// spell-checker:ignore mydir
+// spell-checker:ignore mydir hardlinked tmpfs
+
 use filetime::FileTime;
 use rstest::rstest;
 use std::io::Write;
@@ -1845,24 +1846,17 @@ mod inter_partition_copying {
         let scene = TestScenario::new(util_name!());
         let at = &scene.fixtures;
 
-        // create a file in the current partition.
         at.write("src", "src contents");
 
-        // create a folder in another partition.
         let other_fs_tempdir =
             TempDir::new_in("/dev/shm/").expect("Unable to create temp directory");
-
-        // create a file inside that folder.
         let other_fs_file_path = other_fs_tempdir.path().join("other_fs_file");
         write(&other_fs_file_path, "other fs file contents")
             .expect("Unable to write to other_fs_file");
 
-        // create a symlink to the file inside the same directory.
         let symlink_path = other_fs_tempdir.path().join("symlink_to_file");
         symlink(&other_fs_file_path, &symlink_path).expect("Unable to create symlink_to_file");
 
-        // disable write for the target folder so that when mv tries to remove the
-        // the destination symlink inside the target directory it would fail.
         set_permissions(other_fs_tempdir.path(), PermissionsExt::from_mode(0o555))
             .expect("Unable to set permissions for temp directory");
 
@@ -1875,6 +1869,459 @@ mod inter_partition_copying {
             .stderr_contains("inter-device move failed:")
             .stderr_contains("Permission denied");
     }
+
+    // Test that hardlinks are preserved when moving files across partitions
+    #[test]
+    #[cfg(unix)]
+    pub(crate) fn test_mv_preserves_hardlinks_across_partitions() {
+        use std::fs::metadata;
+        use std::os::unix::fs::MetadataExt;
+        use tempfile::TempDir;
+        use uutests::util::TestScenario;
+
+        let scene = TestScenario::new(util_name!());
+        let at = &scene.fixtures;
+
+        at.write("file1", "test content");
+        at.hard_link("file1", "file2");
+
+        let metadata1 = metadata(at.plus("file1")).expect("Failed to get metadata for file1");
+        let metadata2 = metadata(at.plus("file2")).expect("Failed to get metadata for file2");
+        assert_eq!(
+            metadata1.ino(),
+            metadata2.ino(),
+            "Files should have same inode before move"
+        );
+        assert_eq!(
+            metadata1.nlink(),
+            2,
+            "Files should have nlink=2 before move"
+        );
+
+        // Create a target directory in another partition (using /dev/shm which is typically tmpfs)
+        let other_fs_tempdir = TempDir::new_in("/dev/shm/")
+            .expect("Unable to create temp directory in /dev/shm - test requires tmpfs");
+
+        scene
+            .ucmd()
+            .arg("file1")
+            .arg("file2")
+            .arg(other_fs_tempdir.path().to_str().unwrap())
+            .succeeds();
+
+        assert!(!at.file_exists("file1"), "file1 should not exist in source");
+        assert!(!at.file_exists("file2"), "file2 should not exist in source");
+
+        let moved_file1 = other_fs_tempdir.path().join("file1");
+        let moved_file2 = other_fs_tempdir.path().join("file2");
+        assert!(moved_file1.exists(), "file1 should exist in destination");
+        assert!(moved_file2.exists(), "file2 should exist in destination");
+
+        let moved_metadata1 =
+            metadata(&moved_file1).expect("Failed to get metadata for moved file1");
+        let moved_metadata2 =
+            metadata(&moved_file2).expect("Failed to get metadata for moved file2");
+
+        assert_eq!(
+            moved_metadata1.ino(),
+            moved_metadata2.ino(),
+            "Files should have same inode after cross-partition move (hardlinks preserved)"
+        );
+        assert_eq!(
+            moved_metadata1.nlink(),
+            2,
+            "Files should have nlink=2 after cross-partition move"
+        );
+
+        // Verify content is preserved
+        assert_eq!(
+            std::fs::read_to_string(&moved_file1).expect("Failed to read moved file1"),
+            "test content"
+        );
+        assert_eq!(
+            std::fs::read_to_string(&moved_file2).expect("Failed to read moved file2"),
+            "test content"
+        );
+    }
+
+    // Test that hardlinks are preserved even with multiple sets of hardlinked files
+    #[test]
+    #[cfg(unix)]
+    #[allow(clippy::too_many_lines)]
+    #[allow(clippy::similar_names)]
+    pub(crate) fn test_mv_preserves_multiple_hardlink_groups_across_partitions() {
+        use std::fs::metadata;
+        use std::os::unix::fs::MetadataExt;
+        use tempfile::TempDir;
+        use uutests::util::TestScenario;
+
+        let scene = TestScenario::new(util_name!());
+        let at = &scene.fixtures;
+
+        at.write("group1_file1", "content group 1");
+        at.hard_link("group1_file1", "group1_file2");
+
+        at.write("group2_file1", "content group 2");
+        at.hard_link("group2_file1", "group2_file2");
+
+        at.write("single_file", "single file content");
+
+        let g1f1_meta = metadata(at.plus("group1_file1")).unwrap();
+        let g1f2_meta = metadata(at.plus("group1_file2")).unwrap();
+        let g2f1_meta = metadata(at.plus("group2_file1")).unwrap();
+        let g2f2_meta = metadata(at.plus("group2_file2")).unwrap();
+        let single_meta = metadata(at.plus("single_file")).unwrap();
+
+        assert_eq!(
+            g1f1_meta.ino(),
+            g1f2_meta.ino(),
+            "Group 1 files should have same inode"
+        );
+        assert_eq!(
+            g2f1_meta.ino(),
+            g2f2_meta.ino(),
+            "Group 2 files should have same inode"
+        );
+        assert_ne!(
+            g1f1_meta.ino(),
+            g2f1_meta.ino(),
+            "Different groups should have different inodes"
+        );
+        assert_eq!(single_meta.nlink(), 1, "Single file should have nlink=1");
+
+        let other_fs_tempdir =
+            TempDir::new_in("/dev/shm/").expect("Unable to create temp directory in /dev/shm");
+
+        scene
+            .ucmd()
+            .arg("group1_file1")
+            .arg("group1_file2")
+            .arg("group2_file1")
+            .arg("group2_file2")
+            .arg("single_file")
+            .arg(other_fs_tempdir.path().to_str().unwrap())
+            .succeeds();
+
+        // Verify hardlinks are preserved for both groups
+        let moved_g1f1 = other_fs_tempdir.path().join("group1_file1");
+        let moved_g1f2 = other_fs_tempdir.path().join("group1_file2");
+        let moved_g2f1 = other_fs_tempdir.path().join("group2_file1");
+        let moved_g2f2 = other_fs_tempdir.path().join("group2_file2");
+        let moved_single = other_fs_tempdir.path().join("single_file");
+
+        let moved_g1f1_meta = metadata(&moved_g1f1).unwrap();
+        let moved_g1f2_meta = metadata(&moved_g1f2).unwrap();
+        let moved_g2f1_meta = metadata(&moved_g2f1).unwrap();
+        let moved_g2f2_meta = metadata(&moved_g2f2).unwrap();
+        let moved_single_meta = metadata(&moved_single).unwrap();
+
+        assert_eq!(
+            moved_g1f1_meta.ino(),
+            moved_g1f2_meta.ino(),
+            "Group 1 files should still be hardlinked after move"
+        );
+        assert_eq!(
+            moved_g1f1_meta.nlink(),
+            2,
+            "Group 1 files should have nlink=2"
+        );
+
+        assert_eq!(
+            moved_g2f1_meta.ino(),
+            moved_g2f2_meta.ino(),
+            "Group 2 files should still be hardlinked after move"
+        );
+        assert_eq!(
+            moved_g2f1_meta.nlink(),
+            2,
+            "Group 2 files should have nlink=2"
+        );
+
+        assert_ne!(
+            moved_g1f1_meta.ino(),
+            moved_g2f1_meta.ino(),
+            "Different groups should still have different inodes"
+        );
+
+        assert_eq!(
+            moved_single_meta.nlink(),
+            1,
+            "Single file should still have nlink=1"
+        );
+
+        assert_eq!(
+            std::fs::read_to_string(&moved_g1f1).unwrap(),
+            "content group 1"
+        );
+        assert_eq!(
+            std::fs::read_to_string(&moved_g1f2).unwrap(),
+            "content group 1"
+        );
+        assert_eq!(
+            std::fs::read_to_string(&moved_g2f1).unwrap(),
+            "content group 2"
+        );
+        assert_eq!(
+            std::fs::read_to_string(&moved_g2f2).unwrap(),
+            "content group 2"
+        );
+        assert_eq!(
+            std::fs::read_to_string(&moved_single).unwrap(),
+            "single file content"
+        );
+    }
+
+    // Test the exact GNU test scenario: hardlinks within directories being moved
+    #[test]
+    #[cfg(unix)]
+    pub(crate) fn test_mv_preserves_hardlinks_in_directories_across_partitions() {
+        use std::fs::metadata;
+        use std::os::unix::fs::MetadataExt;
+        use tempfile::TempDir;
+        use uutests::util::TestScenario;
+
+        let scene = TestScenario::new(util_name!());
+        let at = &scene.fixtures;
+
+        at.write("f", "file content");
+        at.hard_link("f", "g");
+
+        at.mkdir("a");
+        at.mkdir("b");
+        at.write("a/1", "directory file content");
+        at.hard_link("a/1", "b/1");
+
+        let f_meta = metadata(at.plus("f")).unwrap();
+        let g_meta = metadata(at.plus("g")).unwrap();
+        let a1_meta = metadata(at.plus("a/1")).unwrap();
+        let b1_meta = metadata(at.plus("b/1")).unwrap();
+
+        assert_eq!(
+            f_meta.ino(),
+            g_meta.ino(),
+            "f and g should have same inode before move"
+        );
+        assert_eq!(f_meta.nlink(), 2, "f should have nlink=2 before move");
+        assert_eq!(
+            a1_meta.ino(),
+            b1_meta.ino(),
+            "a/1 and b/1 should have same inode before move"
+        );
+        assert_eq!(a1_meta.nlink(), 2, "a/1 should have nlink=2 before move");
+
+        let other_fs_tempdir =
+            TempDir::new_in("/dev/shm/").expect("Unable to create temp directory in /dev/shm");
+
+        scene
+            .ucmd()
+            .arg("f")
+            .arg("g")
+            .arg(other_fs_tempdir.path().to_str().unwrap())
+            .succeeds();
+
+        scene
+            .ucmd()
+            .arg("a")
+            .arg("b")
+            .arg(other_fs_tempdir.path().to_str().unwrap())
+            .succeeds();
+
+        let moved_f = other_fs_tempdir.path().join("f");
+        let moved_g = other_fs_tempdir.path().join("g");
+        let moved_f_metadata = metadata(&moved_f).unwrap();
+        let moved_second_file_metadata = metadata(&moved_g).unwrap();
+
+        assert_eq!(
+            moved_f_metadata.ino(),
+            moved_second_file_metadata.ino(),
+            "f and g should have same inode after cross-partition move"
+        );
+        assert_eq!(
+            moved_f_metadata.nlink(),
+            2,
+            "f should have nlink=2 after move"
+        );
+
+        // Verify directory files' hardlinks are preserved (the main test)
+        let moved_dir_a_file = other_fs_tempdir.path().join("a/1");
+        let moved_dir_second_file = other_fs_tempdir.path().join("b/1");
+        let moved_dir_a_file_metadata = metadata(&moved_dir_a_file).unwrap();
+        let moved_dir_second_file_metadata = metadata(&moved_dir_second_file).unwrap();
+
+        assert_eq!(
+            moved_dir_a_file_metadata.ino(),
+            moved_dir_second_file_metadata.ino(),
+            "a/1 and b/1 should have same inode after cross-partition directory move (hardlinks preserved)"
+        );
+        assert_eq!(
+            moved_dir_a_file_metadata.nlink(),
+            2,
+            "a/1 should have nlink=2 after move"
+        );
+
+        assert_eq!(std::fs::read_to_string(&moved_f).unwrap(), "file content");
+        assert_eq!(std::fs::read_to_string(&moved_g).unwrap(), "file content");
+        assert_eq!(
+            std::fs::read_to_string(&moved_dir_a_file).unwrap(),
+            "directory file content"
+        );
+        assert_eq!(
+            std::fs::read_to_string(&moved_dir_second_file).unwrap(),
+            "directory file content"
+        );
+    }
+
+    // Test complex scenario with multiple hardlink groups across nested directories
+    #[test]
+    #[cfg(unix)]
+    #[allow(clippy::too_many_lines)]
+    #[allow(clippy::similar_names)]
+    pub(crate) fn test_mv_preserves_complex_hardlinks_across_nested_directories() {
+        use std::fs::metadata;
+        use std::os::unix::fs::MetadataExt;
+        use tempfile::TempDir;
+        use uutests::util::TestScenario;
+
+        let scene = TestScenario::new(util_name!());
+        let at = &scene.fixtures;
+
+        at.mkdir("dir1");
+        at.mkdir("dir1/subdir1");
+        at.mkdir("dir1/subdir2");
+        at.mkdir("dir2");
+        at.mkdir("dir2/subdir1");
+
+        at.write("dir1/subdir1/file_a", "content A");
+        at.hard_link("dir1/subdir1/file_a", "dir1/subdir2/file_a_link1");
+        at.hard_link("dir1/subdir1/file_a", "dir2/subdir1/file_a_link2");
+
+        at.write("dir1/file_b", "content B");
+        at.hard_link("dir1/file_b", "dir2/file_b_link");
+
+        at.write("dir1/subdir1/nested_file", "nested content");
+        at.hard_link("dir1/subdir1/nested_file", "dir1/subdir2/nested_file_link");
+
+        let orig_file_a_metadata = metadata(at.plus("dir1/subdir1/file_a")).unwrap();
+        let orig_file_a_link1_metadata = metadata(at.plus("dir1/subdir2/file_a_link1")).unwrap();
+        let orig_file_a_link2_metadata = metadata(at.plus("dir2/subdir1/file_a_link2")).unwrap();
+
+        assert_eq!(orig_file_a_metadata.ino(), orig_file_a_link1_metadata.ino());
+        assert_eq!(orig_file_a_metadata.ino(), orig_file_a_link2_metadata.ino());
+        assert_eq!(
+            orig_file_a_metadata.nlink(),
+            3,
+            "file_a group should have nlink=3"
+        );
+
+        let orig_file_b_metadata = metadata(at.plus("dir1/file_b")).unwrap();
+        let orig_file_b_link_metadata = metadata(at.plus("dir2/file_b_link")).unwrap();
+        assert_eq!(orig_file_b_metadata.ino(), orig_file_b_link_metadata.ino());
+        assert_eq!(
+            orig_file_b_metadata.nlink(),
+            2,
+            "file_b group should have nlink=2"
+        );
+
+        let nested_meta = metadata(at.plus("dir1/subdir1/nested_file")).unwrap();
+        let nested_link_meta = metadata(at.plus("dir1/subdir2/nested_file_link")).unwrap();
+        assert_eq!(nested_meta.ino(), nested_link_meta.ino());
+        assert_eq!(
+            nested_meta.nlink(),
+            2,
+            "nested file group should have nlink=2"
+        );
+
+        let other_fs_tempdir =
+            TempDir::new_in("/dev/shm/").expect("Unable to create temp directory in /dev/shm");
+
+        scene
+            .ucmd()
+            .arg("dir1")
+            .arg("dir2")
+            .arg(other_fs_tempdir.path().to_str().unwrap())
+            .succeeds();
+
+        let moved_file_a = other_fs_tempdir.path().join("dir1/subdir1/file_a");
+        let moved_file_a_link1 = other_fs_tempdir.path().join("dir1/subdir2/file_a_link1");
+        let moved_file_a_link2 = other_fs_tempdir.path().join("dir2/subdir1/file_a_link2");
+
+        let final_file_a_metadata = metadata(&moved_file_a).unwrap();
+        let final_file_a_link1_metadata = metadata(&moved_file_a_link1).unwrap();
+        let final_file_a_link2_metadata = metadata(&moved_file_a_link2).unwrap();
+
+        assert_eq!(
+            final_file_a_metadata.ino(),
+            final_file_a_link1_metadata.ino(),
+            "file_a hardlinks should be preserved"
+        );
+        assert_eq!(
+            final_file_a_metadata.ino(),
+            final_file_a_link2_metadata.ino(),
+            "file_a hardlinks should be preserved across directories"
+        );
+        assert_eq!(
+            final_file_a_metadata.nlink(),
+            3,
+            "file_a group should still have nlink=3"
+        );
+
+        let moved_file_b = other_fs_tempdir.path().join("dir1/file_b");
+        let moved_file_b_hardlink = other_fs_tempdir.path().join("dir2/file_b_link");
+        let final_file_b_metadata = metadata(&moved_file_b).unwrap();
+        let final_file_b_hardlink_metadata = metadata(&moved_file_b_hardlink).unwrap();
+
+        assert_eq!(
+            final_file_b_metadata.ino(),
+            final_file_b_hardlink_metadata.ino(),
+            "file_b hardlinks should be preserved"
+        );
+        assert_eq!(
+            final_file_b_metadata.nlink(),
+            2,
+            "file_b group should still have nlink=2"
+        );
+
+        let moved_nested = other_fs_tempdir.path().join("dir1/subdir1/nested_file");
+        let moved_nested_link = other_fs_tempdir
+            .path()
+            .join("dir1/subdir2/nested_file_link");
+        let moved_nested_meta = metadata(&moved_nested).unwrap();
+        let moved_nested_link_meta = metadata(&moved_nested_link).unwrap();
+
+        assert_eq!(
+            moved_nested_meta.ino(),
+            moved_nested_link_meta.ino(),
+            "nested file hardlinks should be preserved"
+        );
+        assert_eq!(
+            moved_nested_meta.nlink(),
+            2,
+            "nested file group should still have nlink=2"
+        );
+
+        assert_eq!(std::fs::read_to_string(&moved_file_a).unwrap(), "content A");
+        assert_eq!(
+            std::fs::read_to_string(&moved_file_a_link1).unwrap(),
+            "content A"
+        );
+        assert_eq!(
+            std::fs::read_to_string(&moved_file_a_link2).unwrap(),
+            "content A"
+        );
+        assert_eq!(std::fs::read_to_string(&moved_file_b).unwrap(), "content B");
+        assert_eq!(
+            std::fs::read_to_string(&moved_file_b_hardlink).unwrap(),
+            "content B"
+        );
+        assert_eq!(
+            std::fs::read_to_string(&moved_nested).unwrap(),
+            "nested content"
+        );
+        assert_eq!(
+            std::fs::read_to_string(&moved_nested_link).unwrap(),
+            "nested content"
+        );
+    }
 }
 
 #[test]
@@ -1892,6 +2339,97 @@ fn test_mv_error_msg_with_multiple_sources_that_does_not_exist() {
         .stderr_contains("mv: cannot stat 'b/': No such file or directory");
 }
 
+// Tests for hardlink preservation (now always enabled)
+#[test]
+#[cfg(all(unix, not(target_os = "android")))]
+fn test_mv_hardlink_preservation() {
+    let (at, mut ucmd) = at_and_ucmd!();
+
+    at.write("file1", "test content");
+    at.hard_link("file1", "file2");
+    at.mkdir("target");
+
+    ucmd.arg("file1")
+        .arg("file2")
+        .arg("target")
+        .succeeds()
+        .no_stderr();
+
+    assert!(at.file_exists("target/file1"));
+    assert!(at.file_exists("target/file2"));
+}
+
+#[test]
+#[cfg(all(unix, not(target_os = "android")))]
+fn test_mv_hardlink_progress_indication() {
+    let (at, mut ucmd) = at_and_ucmd!();
+
+    at.write("file1", "content1");
+    at.write("file2", "content2");
+    at.hard_link("file1", "file1_link");
+
+    at.mkdir("target");
+
+    // Test with progress bar and verbose mode
+    ucmd.arg("--progress")
+        .arg("--verbose")
+        .arg("file1")
+        .arg("file1_link")
+        .arg("file2")
+        .arg("target")
+        .succeeds();
+
+    // Verify all files were moved
+    assert!(at.file_exists("target/file1"));
+    assert!(at.file_exists("target/file1_link"));
+    assert!(at.file_exists("target/file2"));
+}
+
+#[test]
+#[cfg(all(unix, not(target_os = "android")))]
+fn test_mv_mixed_hardlinks_and_regular_files() {
+    use std::fs::metadata;
+    use std::os::unix::fs::MetadataExt;
+
+    let (at, mut ucmd) = at_and_ucmd!();
+
+    // Create a mix of hardlinked and regular files
+    at.write("hardlink1", "hardlink content");
+    at.hard_link("hardlink1", "hardlink2");
+    at.write("regular1", "regular content");
+    at.write("regular2", "regular content 2");
+
+    at.mkdir("target");
+
+    // Move all files (hardlinks automatically preserved)
+    ucmd.arg("hardlink1")
+        .arg("hardlink2")
+        .arg("regular1")
+        .arg("regular2")
+        .arg("target")
+        .succeeds();
+
+    // Verify all files moved
+    assert!(at.file_exists("target/hardlink1"));
+    assert!(at.file_exists("target/hardlink2"));
+    assert!(at.file_exists("target/regular1"));
+    assert!(at.file_exists("target/regular2"));
+
+    // Verify hardlinks are preserved (on same filesystem)
+    let h1_meta = metadata(at.plus("target/hardlink1")).unwrap();
+    let h2_meta = metadata(at.plus("target/hardlink2")).unwrap();
+    let r1_meta = metadata(at.plus("target/regular1")).unwrap();
+    let r2_meta = metadata(at.plus("target/regular2")).unwrap();
+
+    // Hardlinked files should have same inode if on same filesystem
+    if h1_meta.dev() == h2_meta.dev() {
+        assert_eq!(h1_meta.ino(), h2_meta.ino());
+    }
+
+    // Regular files should have different inodes
+    assert_ne!(r1_meta.ino(), r2_meta.ino());
+}
+
 #[cfg(not(windows))]
 #[ignore = "requires access to a different filesystem"]
 #[test]
@@ -1906,3 +2444,47 @@ fn test_special_file_different_filesystem() {
     assert!(Path::new("/dev/shm/tmp/f").exists());
     std::fs::remove_dir_all("/dev/shm/tmp").unwrap();
 }
+
+/// Test cross-device move with permission denied error
+/// This test mimics the scenario from the GNU part-fail test where
+/// a cross-device move fails due to permission errors when removing the target file
+#[test]
+#[cfg(target_os = "linux")]
+fn test_mv_cross_device_permission_denied() {
+    use std::fs::{set_permissions, write};
+    use std::os::unix::fs::PermissionsExt;
+    use tempfile::TempDir;
+    use uutests::util::TestScenario;
+
+    let scene = TestScenario::new(util_name!());
+    let at = &scene.fixtures;
+
+    at.write("k", "source content");
+
+    let other_fs_tempdir =
+        TempDir::new_in("/dev/shm/").expect("Unable to create temp directory in /dev/shm");
+
+    let target_file_path = other_fs_tempdir.path().join("k");
+    write(&target_file_path, "target content").expect("Unable to write target file");
+
+    // Remove write permissions from the directory to cause permission denied
+    set_permissions(other_fs_tempdir.path(), PermissionsExt::from_mode(0o555))
+        .expect("Unable to set directory permissions");
+
+    // Attempt to move file to the other filesystem
+    // This should fail with a permission denied error
+    let result = scene
+        .ucmd()
+        .arg("-f")
+        .arg("k")
+        .arg(target_file_path.to_str().unwrap())
+        .fails();
+
+    // Check that it contains permission denied and references the file
+    // The exact format may vary but should contain these key elements
+    let stderr = result.stderr_str();
+    assert!(stderr.contains("Permission denied") || stderr.contains("permission denied"));
+
+    set_permissions(other_fs_tempdir.path(), PermissionsExt::from_mode(0o755))
+        .expect("Unable to restore directory permissions");
+}