1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2022 SUSE LLC <rpalethorpe@suse.com>
4 */
5/*\
6 *
7 * [Description]
8 *
9 * Perform some I/O on a file and check if at least some of it is
10 * recorded by the I/O controller.
11 *
12 * The exact amount of I/O performed is dependent on the file system,
13 * page cache, scheduler and block driver. We call sync and drop the
14 * file's page cache to force reading and writing. We also write
15 * random data to try to prevent compression.
16 *
17 * The pagecache is a particular issue for reading. If the call to
18 * fadvise is ignored then the data may only be read from the
19 * cache. So that no I/O requests are made.
20 */
21
22#include <stdio.h>
23#include <stdlib.h>
24#include <sys/sysmacros.h>
25
26#include "tst_test.h"
27
28struct io_stats {
29	unsigned int mjr;
30	unsigned int mnr;
31	unsigned long rbytes;
32	unsigned long wbytes;
33	unsigned long rios;
34	unsigned long wios;
35	unsigned long dbytes;
36	unsigned long dios;
37};
38
39static unsigned int dev_major, dev_minor;
40
41static int read_io_stats(const char *const line, struct io_stats *const stat)
42{
43	return sscanf(line,
44		      "%u:%u rbytes=%lu wbytes=%lu rios=%lu wios=%lu dbytes=%lu dios=%lu",
45		      &stat->mjr, &stat->mnr,
46		      &stat->rbytes, &stat->wbytes, &stat->rios, &stat->wios,
47		      &stat->dbytes, &stat->dios);
48}
49
50static void run(void)
51{
52	int i, fd;
53	char *line, *buf_ptr;
54	const size_t pgsz = SAFE_SYSCONF(_SC_PAGESIZE);
55	char *buf = SAFE_MALLOC(MAX((size_t)BUFSIZ, pgsz));
56	struct io_stats start;
57
58	memset(&start, 0, sizeof(struct io_stats));
59	SAFE_CG_READ(tst_cg, "io.stat", buf, BUFSIZ - 1);
60	line = strtok_r(buf, "\n", &buf_ptr);
61	while (line) {
62		const int convs = read_io_stats(line, &start);
63
64		if (convs < 2)
65			continue;
66
67		tst_res(TINFO, "Found %u:%u in io.stat", dev_major, dev_minor);
68
69		if (start.mjr == dev_major || start.mnr == dev_minor)
70			break;
71
72		line = strtok_r(NULL, "\n", &buf_ptr);
73	}
74
75	SAFE_CG_PRINTF(tst_cg, "cgroup.procs", "%d", getpid());
76
77	fd = SAFE_OPEN("/dev/urandom", O_RDONLY, 0600);
78	SAFE_READ(1, fd, buf, pgsz);
79	SAFE_CLOSE(fd);
80
81	fd = SAFE_OPEN("mnt/dat", O_WRONLY | O_CREAT, 0600);
82
83	for (i = 0; i < 4; i++) {
84		SAFE_WRITE(SAFE_WRITE_ALL, fd, buf, pgsz);
85		SAFE_FSYNC(fd);
86		TST_EXP_PASS_SILENT(posix_fadvise(fd, pgsz * i, pgsz, POSIX_FADV_DONTNEED));
87	}
88
89	SAFE_CLOSE(fd);
90	fd = SAFE_OPEN("mnt/dat", O_RDONLY, 0600);
91
92	for (i = 0; i < 4; i++)
93		SAFE_READ(1, fd, buf, pgsz);
94
95	tst_res(TPASS, "Did some IO in the IO controller");
96
97	SAFE_CG_READ(tst_cg, "io.stat", buf, BUFSIZ - 1);
98	line = strtok_r(buf, "\n", &buf_ptr);
99	while (line) {
100		struct io_stats end;
101		const int convs = read_io_stats(line, &end);
102
103		if (convs < 8)
104			break;
105
106		if (end.mjr != dev_major || end.mnr != dev_minor) {
107			line = strtok_r(NULL, "\n", &buf_ptr);
108			continue;
109		}
110
111		tst_res(TPASS, "Found %u:%u in io.stat", dev_major, dev_minor);
112		TST_EXP_EXPR(end.rbytes > start.rbytes,
113			     "(rbytes=%lu) > (st_rbytes=%lu)",
114			     end.rbytes, start.rbytes);
115		TST_EXP_EXPR(end.wbytes > start.wbytes,
116			     "(wbytes=%lu) > (st_wbytes=%lu)",
117			     end.wbytes, start.wbytes);
118		TST_EXP_EXPR(end.rios > start.rios,
119			     "(rios=%lu) > (st_rios=%lu)",
120			     end.rios, start.rios);
121		TST_EXP_EXPR(end.wios > start.wios,
122			     "(wios=%lu) > (st_wios=%lu)",
123			     end.wios, start.wios);
124
125		goto out;
126	}
127
128	tst_res(TINFO, "io.stat:\n%s", buf);
129	tst_res(TFAIL, "Did not find %u:%u in io.stat", dev_major, dev_minor);
130out:
131	free(buf);
132	SAFE_CLOSE(fd);
133	SAFE_UNLINK("mnt/dat");
134}
135
136static void setup(void)
137{
138	char buf[PATH_MAX] = { 0 };
139	char *path = SAFE_GETCWD(buf, PATH_MAX - sizeof("mnt") - 1);
140	struct stat st;
141
142	strcpy(path + strlen(path), "/mnt");
143
144	tst_stat_mount_dev(path, &st);
145	dev_major = major(st.st_rdev);
146	dev_minor = minor(st.st_rdev);
147}
148
149static struct tst_test test = {
150	.test_all = run,
151	.setup = setup,
152	.mntpoint = "mnt",
153	.mount_device = 1,
154	.all_filesystems = 1,
155	.skip_filesystems = (const char *const[]){ "ntfs", "tmpfs", NULL },
156	.needs_cgroup_ver = TST_CG_V2,
157	.needs_cgroup_ctrls = (const char *const[]){ "io", NULL },
158};
159