1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2020 FUJITSU LIMITED. All rights reserved.
4 * Author: Yang Xu <xuyang2018.jy@cn.jujitsu.com>
5 *
6 * This is a basic ioctl test about loopdevice.
7 *
8 * It is designed to test LOOP_SET_DIRECT_IO can update a live
9 * loop device dio mode. It needs the backing file also supports
10 * dio mode and the lo_offset is aligned with the logical block size.
11 *
12 * The direct I/O error handling is a bit messy on Linux, some filesystems
13 * return error when it coudln't be enabled, some silently fall back to regular
14 * buffered I/O.
15 *
16 * The LOOP_SET_DIRECT_IO ioctl() may ignore all checks if it cannot get the
17 * logical block size which is the case if the block device pointer in the
18 * backing file inode is not set. In this case the direct I/O appears to be
19 * enabled but falls back to buffered I/O later on. This is the case at least
20 * for Btrfs. Because of that the test passes both with failure as well as
21 * success with non-zero offset.
22 */
23
24 #include <stdio.h>
25 #include <unistd.h>
26 #include <string.h>
27 #include <stdlib.h>
28 #include <sys/mount.h>
29 #include "lapi/loop.h"
30 #include "tst_test.h"
31
32 #define DIO_MESSAGE "In dio mode"
33 #define NON_DIO_MESSAGE "In non dio mode"
34
35 static char dev_path[1024], sys_loop_diopath[1024], backing_file_path[1024];;
36 static int dev_num, dev_fd, block_devfd, attach_flag, logical_block_size;
37
check_dio_value(int flag)38 static void check_dio_value(int flag)
39 {
40 struct loop_info loopinfoget;
41
42 memset(&loopinfoget, 0, sizeof(loopinfoget));
43
44 SAFE_IOCTL(dev_fd, LOOP_GET_STATUS, &loopinfoget);
45 tst_res(TINFO, "%s", flag ? DIO_MESSAGE : NON_DIO_MESSAGE);
46
47 if (loopinfoget.lo_flags & LO_FLAGS_DIRECT_IO)
48 tst_res(flag ? TPASS : TFAIL, "lo_flags has LO_FLAGS_DIRECT_IO flag");
49 else
50 tst_res(flag ? TFAIL : TPASS, "lo_flags doesn't have LO_FLAGS_DIRECT_IO flag");
51
52 TST_ASSERT_INT(sys_loop_diopath, flag);
53 }
54
verify_ioctl_loop(void)55 static void verify_ioctl_loop(void)
56 {
57 struct loop_info loopinfo;
58
59 memset(&loopinfo, 0, sizeof(loopinfo));
60 TST_RETRY_FUNC(ioctl(dev_fd, LOOP_SET_STATUS, &loopinfo), TST_RETVAL_EQ0);
61
62 tst_res(TINFO, "Without setting lo_offset or sizelimit");
63 SAFE_IOCTL(dev_fd, LOOP_SET_DIRECT_IO, 1);
64 check_dio_value(1);
65
66 SAFE_IOCTL(dev_fd, LOOP_SET_DIRECT_IO, 0);
67 check_dio_value(0);
68
69 tst_res(TINFO, "With offset equal to logical_block_size");
70 loopinfo.lo_offset = logical_block_size;
71 TST_RETRY_FUNC(ioctl(dev_fd, LOOP_SET_STATUS, &loopinfo), TST_RETVAL_EQ0);
72 TEST(ioctl(dev_fd, LOOP_SET_DIRECT_IO, 1));
73 if (TST_RET == 0) {
74 tst_res(TPASS, "LOOP_SET_DIRECT_IO succeeded");
75 check_dio_value(1);
76 SAFE_IOCTL(dev_fd, LOOP_SET_DIRECT_IO, 0);
77 } else {
78 tst_res(TFAIL | TTERRNO, "LOOP_SET_DIRECT_IO failed");
79 }
80
81 tst_res(TINFO, "With nonzero offset less than logical_block_size");
82 loopinfo.lo_offset = logical_block_size / 2;
83 TST_RETRY_FUNC(ioctl(dev_fd, LOOP_SET_STATUS, &loopinfo), TST_RETVAL_EQ0);
84
85 TEST(ioctl(dev_fd, LOOP_SET_DIRECT_IO, 1));
86 if (TST_RET == 0) {
87 tst_res(TPASS, "LOOP_SET_DIRECT_IO succeeded, offset is ignored");
88 SAFE_IOCTL(dev_fd, LOOP_SET_DIRECT_IO, 0);
89 return;
90 }
91 if (TST_ERR == EINVAL)
92 tst_res(TPASS | TTERRNO, "LOOP_SET_DIRECT_IO failed as expected");
93 else
94 tst_res(TFAIL | TTERRNO, "LOOP_SET_DIRECT_IO failed expected EINVAL got");
95 }
96
setup(void)97 static void setup(void)
98 {
99 char bd_path[100];
100
101 dev_num = tst_find_free_loopdev(dev_path, sizeof(dev_path));
102 if (dev_num < 0)
103 tst_brk(TBROK, "Failed to find free loop device");
104
105 sprintf(sys_loop_diopath, "/sys/block/loop%d/loop/dio", dev_num);
106 tst_fill_file("test.img", 0, 1024, 1024);
107
108 tst_attach_device(dev_path, "test.img");
109 attach_flag = 1;
110 dev_fd = SAFE_OPEN(dev_path, O_RDWR);
111
112 if (ioctl(dev_fd, LOOP_SET_DIRECT_IO, 0) && errno == EINVAL)
113 tst_brk(TCONF, "LOOP_SET_DIRECT_IO is not supported");
114
115 /*
116 * from __loop_update_dio():
117 * We support direct I/O only if lo_offset is aligned with the
118 * logical I/O size of backing device, and the logical block
119 * size of loop is bigger than the backing device's and the loop
120 * needn't transform transfer.
121 */
122 sprintf(backing_file_path, "%s/test.img", tst_get_tmpdir());
123 tst_find_backing_dev(backing_file_path, bd_path);
124 block_devfd = SAFE_OPEN(bd_path, O_RDWR);
125 SAFE_IOCTL(block_devfd, BLKSSZGET, &logical_block_size);
126 tst_res(TINFO, "backing dev(%s) logical_block_size is %d", bd_path, logical_block_size);
127 SAFE_CLOSE(block_devfd);
128 if (logical_block_size > 512)
129 TST_RETRY_FUNC(ioctl(dev_fd, LOOP_SET_BLOCK_SIZE, logical_block_size), TST_RETVAL_EQ0);
130 }
131
cleanup(void)132 static void cleanup(void)
133 {
134 if (dev_fd > 0)
135 SAFE_CLOSE(dev_fd);
136 if (block_devfd > 0)
137 SAFE_CLOSE(block_devfd);
138 if (attach_flag)
139 tst_detach_device(dev_path);
140 }
141
142 static struct tst_test test = {
143 .setup = setup,
144 .cleanup = cleanup,
145 .test_all = verify_ioctl_loop,
146 .needs_root = 1,
147 .needs_tmpdir = 1,
148 .skip_filesystems = (const char *const []) {
149 "tmpfs",
150 "overlayfs",
151 NULL
152 },
153 .needs_drivers = (const char *const []) {
154 "loop",
155 NULL
156 }
157 };
158