syscalls/ioctl_loop04: Add LOOP_SET_CAPACITY ioctl test

LOOP_SET_CAPACITY can update a live loop device size when we
change the size of the underlying backing file. Also check sys
value.

Signed-off-by: Yang Xu <[email protected]>
Reviewed-by: Cyril Hrubis <[email protected]>

Author: xuyang0410

runtest/syscalls

@@ -532,6 +532,7 @@ ioctl08      ioctl08
 ioctl_loop01 ioctl_loop01
 ioctl_loop02 ioctl_loop02
 ioctl_loop03 ioctl_loop03
+ioctl_loop04 ioctl_loop04
 
 ioctl_ns01 ioctl_ns01
 ioctl_ns02 ioctl_ns02

testcases/kernel/syscalls/ioctl/.gitignore

@@ -9,6 +9,7 @@
 /ioctl_loop01
 /ioctl_loop02
 /ioctl_loop03
+/ioctl_loop04
 /ioctl_ns01
 /ioctl_ns02
 /ioctl_ns03

testcases/kernel/syscalls/ioctl/ioctl_loop04.c

@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2020 FUJITSU LIMITED. All rights reserved.
+ * Author: Yang Xu <[email protected]>
+ *
+ * This is a basic ioctl test about loopdevice.
+ *
+ * It is designed to test LOOP_SET_CAPACITY can update a live
+ * loop device size when we change the size of the underlying
+ * backing file. Also check sys value.
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include "lapi/loop.h"
+#include "tst_test.h"
+
+#define OLD_SIZE 10240
+#define NEW_SIZE 5120
+
+static char dev_path[1024], sys_loop_sizepath[1024];
+static char *wrbuf;
+static int dev_num, dev_fd, file_fd, attach_flag;
+
+static void verify_ioctl_loop(void)
+{
+	struct loop_info loopinfoget;
+
+	memset(&loopinfoget, 0, sizeof(loopinfoget));
+	tst_fill_file("test.img", 0, 1024, OLD_SIZE/1024);
+	tst_attach_device(dev_path, "test.img");
+	attach_flag = 1;
+
+	TST_ASSERT_INT(sys_loop_sizepath, OLD_SIZE/512);
+	dev_fd = SAFE_OPEN(dev_path, O_RDWR);
+	file_fd = SAFE_OPEN("test.img", O_RDWR);
+	SAFE_IOCTL(dev_fd, LOOP_GET_STATUS, &loopinfoget);
+
+	if (loopinfoget.lo_flags & LO_FLAGS_READ_ONLY)
+		tst_brk(TCONF, "Current environment has unexpected LO_FLAGS_READ_ONLY flag");
+
+	SAFE_TRUNCATE("test.img", NEW_SIZE);
+	SAFE_IOCTL(dev_fd, LOOP_SET_CAPACITY);
+
+	/*check that we can't write data beyond 5K into loop device*/
+	TEST(write(dev_fd, wrbuf, OLD_SIZE));
+	if (TST_RET == NEW_SIZE) {
+		tst_res(TPASS, "LOOP_SET_CAPACITY set loop size to %d", NEW_SIZE);
+	} else {
+		tst_res(TFAIL, "LOOP_SET_CAPACITY didn't set loop size to %d, its size is %ld",
+				NEW_SIZE, TST_RET);
+	}
+
+	TST_ASSERT_INT(sys_loop_sizepath, NEW_SIZE/512);
+
+	SAFE_CLOSE(file_fd);
+	SAFE_CLOSE(dev_fd);
+	tst_detach_device(dev_path);
+	unlink("test.img");
+	attach_flag = 0;
+}
+
+static void setup(void)
+{
+	dev_num = tst_find_free_loopdev(dev_path, sizeof(dev_path));
+	if (dev_num < 0)
+		tst_brk(TBROK, "Failed to find free loop device");
+
+	wrbuf = SAFE_MALLOC(OLD_SIZE);
+	memset(wrbuf, 'x', OLD_SIZE);
+	sprintf(sys_loop_sizepath, "/sys/block/loop%d/size", dev_num);
+}
+
+static void cleanup(void)
+{
+	if (dev_fd > 0)
+		SAFE_CLOSE(dev_fd);
+	if (file_fd > 0)
+		SAFE_CLOSE(file_fd);
+	if (wrbuf)
+		free(wrbuf);
+	if (attach_flag)
+		tst_detach_device(dev_path);
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.test_all = verify_ioctl_loop,
+	.needs_root = 1,
+	.needs_tmpdir = 1,
+	.needs_drivers = (const char *const []) {
+		"loop",
+		NULL
+	}
+};