btrfs-progs: tests: make sure rootdir inode gets its attributes copied

The new test case would:

- Prepare two loopback devices
  One is for storing the source directory (on a btrfs).
  This is to ensure we can set xattr for the directory, as filesystems
  like tmpfs (mostly utilized by mktemp) is not supporting xattr.

  The other one is the real target fs where we call
  "mkfs.btrfs --rootdir" on.

- Create the source directory with the following contents:
  * rootdir inode attributs:
    # mode (750)
    # uid (1000)
    # gid (1000)
    # xattr (user.rootdir)
  * one regular file, with attributes:
    # xattr (user.foorbar)

- Execute "mkfs.btrfs --rootdir" and mount the new fs

- Verify the above attributes
  The target fs should have the same attributes, especially for the
  rootdir inode.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

tests/mkfs-tests/027-rootdir-inode/test.sh

@@ -0,0 +1,61 @@
+#!/bin/bash
+# Test if "mkfs.btrfs --rootdir" would properly copy all the attributes of the
+# source directory.
+
+source "$TEST_TOP/common" || exit
+
+setup_root_helper
+
+# Here we need two devices, one as a temporaray btrfs, storing the source
+# directory. As we want to setup xattr, which is not supported by tmpfs
+# (most modern distros use tmpfs for /tmp).
+# So we put the source directory on a fs that reliably supports xattr.
+#
+# Then the second fs is the real one we mkfs on.
+setup_loopdevs 2
+prepare_loopdevs
+
+tmp_dev=${loopdevs[1]}
+real_dev=${loopdevs[2]}
+
+check_global_prereq setfattr
+check_global_prereq getfattr
+
+# Here we don't want to use /tmp, as it's pretty common /tmp is tmpfs, which
+# doesn't support xattr.
+# Instead we go $TEST_TOP/btrfs-progs-mkfs-tests-027.XXXXXX/ instead.
+run_check $SUDO_HELPER "$TOP/mkfs.btrfs" -f "$tmp_dev"
+run_check $SUDO_HELPER mount -t btrfs "$tmp_dev" "$TEST_MNT"
+
+run_check $SUDO_HELPER mkdir "$TEST_MNT/source_dir/"
+run_check $SUDO_HELPER chmod 750 "$TEST_MNT/source_dir/"
+run_check $SUDO_HELPER chown 1000:1000 "$TEST_MNT/source_dir/"
+run_check $SUDO_HELPER setfattr -n user.rootdir "$TEST_MNT/source_dir/"
+
+old_mode=$(run_check_stdout $SUDO_HELPER stat "$TEST_MNT/source_dir/" | grep "Uid:")
+run_check $SUDO_HELPER touch "$TEST_MNT/source_dir/foobar"
+run_check $SUDO_HELPER setfattr -n user.foobar "$TEST_MNT/source_dir/foobar"
+
+run_check $SUDO_HELPER "$TOP/mkfs.btrfs" --rootdir "$TEST_MNT/source_dir" -f "$real_dev"
+run_check $SUDO_HELPER umount "$TEST_MNT"
+
+run_check $SUDO_HELPER mount -t btrfs "$real_dev" "$TEST_MNT"
+
+new_mode=$(run_check_stdout $SUDO_HELPER stat "$TEST_MNT/" | grep "Uid:")
+new_rootdir_attr=$(run_check_stdout $SUDO_HELPER getfattr -n user.rootdir --absolute-names "$src_dir")
+new_foobar_attr=$(run_check_stdout getfattr -n user.foobar --absolute-names "$src_dir/foobar")
+
+run_check_umount_test_dev "$TEST_MNT"
+cleanup_loopdevs
+
+if ! echo "$new_rootdir_attr" | grep -q "user.rootdir" ; then
+	_fail "no rootdir xattr found"
+fi
+
+if ! echo "$new_foobar_attr"| grep -q "user.foobar" ; then
+	_fail "no regular file xattr found"
+fi
+
+if [ "$new_mode" != "$old_mode" ]; then
+	_fail "mode/uid/gid mismatch"
+fi