common/casefold: Add infrastructure to test filename casefold feature

Add a set of basic helper functions to simplify the testing of
casefolding capable filesystems.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

diff --git a/common/casefold b/common/casefold
new file mode 100644 (file)
index 0000000..051fd1d
--- /dev/null
+++ b/common/casefold
@@ -0,0 +1,90 @@
+# SPDX-License-Identifier: GPL-2.0+
+# Copyright (c) 2019 Collabora, Ltd.  All Rights Reserved.
+#
+# Common functions for testing filename casefold feature
+
+_has_casefold_kernel_support()
+{
+       case $FSTYP in
+       ext4)
+               test -f '/sys/fs/ext4/features/casefold'
+               ;;
+       *)
+               # defaults to unsupported
+               false
+               ;;
+       esac
+}
+
+_require_scratch_casefold()
+{
+       if ! _has_casefold_kernel_support ; then
+               _notrun "$FSTYP does not support casefold feature"
+       fi
+
+       if ! _scratch_mkfs_casefold &>>seqres.full; then
+               _notrun "$FSTYP userspace tools do not support casefold"
+       fi
+
+       # Make sure the kernel can mount a filesystem with the encoding
+       # defined by the userspace tools.  This will fail if
+       # the userspace tool used a more recent encoding than the one
+       # supported in kernel space.
+       if ! _try_scratch_mount &>>seqres.full; then
+               _notrun "kernel can't mount filesystem with the encoding set by userspace"
+       fi
+       _scratch_unmount
+
+       # utilities used by casefold
+       _require_command "$CHATTR_PROG" chattr
+       _require_command "$LSATTR_PROG" lsattr
+}
+
+_scratch_mkfs_casefold()
+{
+       case $FSTYP in
+       ext4)
+               _scratch_mkfs -O casefold $*
+               ;;
+       *)
+               _notrun "Don't know how to mkfs with casefold support on $FSTYP"
+               ;;
+       esac
+}
+
+_scratch_mkfs_casefold_strict()
+{
+       case $FSTYP in
+       ext4)
+               _scratch_mkfs -O casefold -E encoding_flags=strict
+               ;;
+       *)
+               _notrun "Don't know how to mkfs with casefold-strict support on $FSTYP"
+               ;;
+       esac
+}
+
+# To get the exact disk name, we need some method that does a
+# getdents() on the parent directory, such that we don't get
+# normalized/casefolded results.  'Find' works ok.
+_casefold_check_exact_name()
+{
+       local basedir=$1
+       local exact_name=$2
+       find ${basedir} | grep -q ${exact_name}
+}
+
+_casefold_set_attr()
+{
+       $CHATTR_PROG +F "${1}"
+}
+
+_casefold_unset_attr()
+{
+       $CHATTR_PROG -F "${1}"
+}
+
+_casefold_lsattr_dir()
+{
+       $LSATTR_PROG -ld "${1}" | _filter_spaces
+}