syscalls: add file_attr05 test

Verify that `file_setattr` is correctly raising EOPNOTSUPP when
filesystem doesn't support FSX operations.

Regression test for 474b155adf392 ("fs: make vfs_fileattr_[get|set]
return -EOPNOTSUPP").

Reviewed-by: Petr Vorel <pvorel@suse.cz>
Reviewed-by: Li Wang <liwang@redhat.com>
Reviewed-by: Cyril Hrubis <chrubis@suse.cz>
Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>

Author: acerv

runtest/syscalls

@@ -253,6 +253,7 @@ file_attr01 file_attr01
 file_attr02 file_attr02
 file_attr03 file_attr03
 file_attr04 file_attr04
+file_attr05 file_attr05
 
 #posix_fadvise test cases
 posix_fadvise01                      posix_fadvise01

testcases/kernel/syscalls/file_attr/.gitignore

@@ -2,3 +2,4 @@ file_attr01
 file_attr02
 file_attr03
 file_attr04
+file_attr05

testcases/kernel/syscalls/file_attr/file_attr05.c

@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2025 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
+ */
+
+/*\
+ * Verify that `file_setattr` is correctly raising EOPNOTSUPP when filesystem
+ * doesn't support FSX operations.
+ */
+
+#include "tst_test.h"
+#include "lapi/fs.h"
+
+#define MNTPOINT "mntpoint"
+#define FILEPATH (MNTPOINT "/ltp_file")
+#define BLOCKS 128
+#define PROJID 16
+
+static struct file_attr *attr_set;
+
+static void run(void)
+{
+	TST_EXP_FAIL(file_setattr(AT_FDCWD, FILEPATH,
+			   attr_set, FILE_ATTR_SIZE_LATEST, 0), EOPNOTSUPP);
+}
+
+static void setup(void)
+{
+	struct stat statbuf;
+
+	SAFE_TOUCH(FILEPATH, 0777, NULL);
+
+	SAFE_STAT(MNTPOINT, &statbuf);
+
+	attr_set->fa_xflags |= FS_XFLAG_EXTSIZE;
+	attr_set->fa_xflags |= FS_XFLAG_COWEXTSIZE;
+	attr_set->fa_extsize = BLOCKS * statbuf.st_blksize;
+	attr_set->fa_cowextsize = BLOCKS * statbuf.st_blksize;
+	attr_set->fa_projid = PROJID;
+}
+
+static struct tst_test test = {
+	.test_all = run,
+	.setup = setup,
+	.mntpoint = MNTPOINT,
+	.needs_root = 1,
+	.mount_device = 1,
+	.all_filesystems = 1,
+	.skip_filesystems = (const char *const []) {
+		"xfs",
+		"fuse", /* EINVAL is raised before EOPNOTSUPP */
+		"vfat", /* vfat is not implementing file_[set|get]attr */
+		NULL,
+	},
+	.bufs = (struct tst_buffers []) {
+		{&attr_set, .size = sizeof(struct file_attr)},
+		{}
+	},
+	.tags = (const struct tst_tag[]) {
+		{"linux-git", "474b155adf392"},
+		{},
+	}
+};