ficlone: improve error reporting in do_ficlone_dir; factor out shared safeguard tests

- Add stderr messages for previously silent failure paths in do_ficlone_dir:
  lstat, readlink, symlink, and unlink of src_child all now print the
  filename and error string.
- Add files_moved counter; emit a partial-move warning (naming both src
  and dst) only when at least one entry was already transferred before
  the failure, so a clean early failure stays silent.
- Factor the two read-only-dir safeguard test cases out of
  test_btrfs_clone.sh and test_bcachefs.sh into
  test/test_ficlone_safeguards.sh; each script now sets
  FS_MOUNTPOINT/FS_RMW_CMD/FS_WASTE_DIR and sources the shared file.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: andy5995

src/ficlone.c

@@ -127,6 +127,10 @@ do_ficlone(const char *source, const char *dest, int *save_errno)
   {
     *save_errno = errno;
     perror("unlink source");
+    /* dest is a valid clone but source couldn't be removed; clean up dest
+       so the caller can retry rather than leaving an orphan in the waste folder */
+    if (unlink(dest) != 0)
+      fprintf(stderr, "unlink: %s in %s\n", strerror(errno), __func__);
     return -1;
   }
 
@@ -162,6 +166,7 @@ do_ficlone_dir(const char *src, const char *dst, int *save_errno)
   }
 
   int result = 0;
+  int files_moved = 0;
   struct dirent *entry;
   while ((entry = readdir(dir)) != NULL)
   {
@@ -175,6 +180,7 @@ do_ficlone_dir(const char *src, const char *dst, int *save_errno)
     if (lstat(src_child, &st) != 0)
     {
       *save_errno = errno;
+      fprintf(stderr, "lstat '%s': %s\n", src_child, strerror(*save_errno));
       result = -1;
     }
     else
@@ -193,6 +199,7 @@ do_ficlone_dir(const char *src, const char *dst, int *save_errno)
         if (len == -1)
         {
           *save_errno = errno;
+          fprintf(stderr, "readlink '%s': %s\n", src_child, strerror(*save_errno));
           result = -1;
         }
         else
@@ -201,11 +208,15 @@ do_ficlone_dir(const char *src, const char *dst, int *save_errno)
           if (symlink(link_target, dst_child) != 0)
           {
             *save_errno = errno;
+            fprintf(stderr, "symlink '%s': %s\n", dst_child, strerror(*save_errno));
             result = -1;
           }
           else if (unlink(src_child) != 0)
           {
             *save_errno = errno;
+            fprintf(stderr, "unlink '%s': %s\n", src_child, strerror(*save_errno));
+            /* src_child is still intact; remove dst_child to avoid duplicate */
+            unlink(dst_child);
             result = -1;
           }
         }
@@ -224,12 +235,19 @@ do_ficlone_dir(const char *src, const char *dst, int *save_errno)
 
     if (result != 0)
       break;
+    files_moved++;
   }
 
   closedir(dir);
 
   if (result != 0)
+  {
+    if (files_moved > 0)
+      fprintf(stderr,
+              "partial move: check both '%s' and '%s' -- some files may have already been moved\n",
+              src, dst);
     return -1;
+  }
 
   if (rmdir(src) != 0)
   {

test/test_bcachefs.sh

@@ -159,6 +159,11 @@ test -f "$BCACHEFS_SYM_DIR/real_file"
 test -L "$BCACHEFS_SYM_DIR/link_file"
 test ! -f "$BCACHEFS_WASTE_DIR/info/sym_dir.trashinfo"
 
+FS_MOUNTPOINT="$BCACHEFS_MOUNTPOINT"
+FS_RMW_CMD="$BCACHEFS_RMW_CMD"
+FS_WASTE_DIR="$BCACHEFS_WASTE_DIR"
+. "${MESON_SOURCE_ROOT}/test/test_ficlone_safeguards.sh"
+
 # --- Test: purge an expired file from bcachefs waste ---
 echo "== Test: purge an expired file from bcachefs waste"
 RMW_FAKE_YEAR=true $BCACHEFS_RMW_CMD foo

test/test_btrfs_clone.sh

@@ -122,6 +122,11 @@ test -f "$BTRFS_SYM_DIR/real_file"
 test -L "$BTRFS_SYM_DIR/link_file"
 test ! -f "$BTRFS_WASTE_DIR/info/sym_dir.trashinfo"
 
+FS_MOUNTPOINT="$BTRFS_MOUNTPOINT"
+FS_RMW_CMD="$BTRFS_RMW_CMD"
+FS_WASTE_DIR="$BTRFS_WASTE_DIR"
+. "${MESON_SOURCE_ROOT}/test/test_ficlone_safeguards.sh"
+
 # --- Test: move a file across btrfs subvolumes ---
 echo "== Test: move a file across btrfs subvolumes"
 touch foo

test/test_ficlone_safeguards.sh

@@ -0,0 +1,29 @@
+# Sourced by test_btrfs_clone.sh and test_bcachefs.sh.
+# Requires: FS_MOUNTPOINT, FS_RMW_CMD, FS_WASTE_DIR
+
+# --- Test: no orphan file in waste when source unlink fails ---
+echo "== Test: no orphan in waste when source file unlink fails"
+FS_RO_DIR="$FS_MOUNTPOINT/ro_dir"
+chmod 0755 "$FS_RO_DIR" 2>/dev/null || true
+rm -rf "$FS_RO_DIR"
+mkdir "$FS_RO_DIR"
+touch "$FS_RO_DIR/file"
+chmod 0555 "$FS_RO_DIR"
+$FS_RMW_CMD "$FS_RO_DIR" || true
+chmod 0755 "$FS_RO_DIR"
+test ! -f "$FS_WASTE_DIR/files/ro_dir/file"
+test -f "$FS_RO_DIR/file"
+rm -rf "$FS_RO_DIR"
+
+# --- Test: no orphan symlink in waste when source symlink unlink fails ---
+echo "== Test: no orphan symlink in waste when source symlink unlink fails"
+chmod 0755 "$FS_RO_DIR" 2>/dev/null || true
+rm -rf "$FS_RO_DIR"
+mkdir "$FS_RO_DIR"
+ln -s nonexistent "$FS_RO_DIR/link"
+chmod 0555 "$FS_RO_DIR"
+$FS_RMW_CMD "$FS_RO_DIR" || true
+chmod 0755 "$FS_RO_DIR"
+test ! -L "$FS_WASTE_DIR/files/ro_dir/link"
+test -L "$FS_RO_DIR/link"
+rm -rf "$FS_RO_DIR"