1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (c) 2004 Daniel McNeil <daniel@osdl.org>
4 *				 2004 Open Source Development Lab
5 * Copyright (C) 2021 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
6 */
7
8/*\
9 * [Description]
10 *
11 * This test is mixing direct I/O and truncate operations checking if they can
12 * be used together at the same time. Multiple children are spawned to read a
13 * file that is written to using direct I/O and truncated in a loop.
14 *
15 * [Algorithm]
16 *
17 * - Spawn multiple children which start to read on 'file'
18 * - Parent start to fill and truncate 'file' many times with zero char when
19 *   children are reading
20 * - Parent start to fill and truncate a junk file many times with non-zero char
21 *
22 * If no issues occur on direct IO/truncate operations and the file always
23 * contains zero characters, test PASS. Otherwise, test will FAIL.
24 */
25
26#define _GNU_SOURCE
27
28#include <stdlib.h>
29#include <stdio.h>
30#include <sys/stat.h>
31#include <sys/types.h>
32#include <fcntl.h>
33#include "tst_test.h"
34#include "tst_kconfig.h"
35#include "common.h"
36
37static volatile int *run_child;
38
39static char *str_numchildren;
40static char *str_filesize;
41static char *str_numappends;
42static char *str_numwrites;
43
44static int numchildren = 16;
45static long long filesize = 64 * 1024;
46static long long alignment;
47static int numappends = 100;
48static int numwrites = 100;
49
50static void dio_read(const char *filename, long long align, size_t bs)
51{
52	int fd;
53	int r;
54	char *bufptr;
55
56	while ((fd = open(filename, O_RDONLY | O_DIRECT, 0666)) < 0)
57		usleep(100);
58
59	bufptr = SAFE_MEMALIGN(align, bs);
60
61	tst_res(TINFO, "child %i reading file", getpid());
62	while (*run_child) {
63		off_t offset;
64		char *bufoff;
65
66		offset = SAFE_LSEEK(fd, SEEK_SET, 0);
67		do {
68			r = read(fd, bufptr, 64 * 1024);
69			if (r > 0) {
70				bufoff = check_zero(bufptr, r);
71				if (bufoff) {
72					tst_res(TINFO, "non-zero read at offset %zu",
73						offset + (bufoff - bufptr));
74					free(bufptr);
75					SAFE_CLOSE(fd);
76					return;
77				}
78				offset += r;
79			}
80		} while (r > 0);
81	}
82
83	free(bufptr);
84	SAFE_CLOSE(fd);
85}
86
87static void setup(void)
88{
89	struct stat sb;
90	static const char * const kconf_rt[] = {"CONFIG_PREEMPT_RT", NULL};
91
92	if (tst_parse_int(str_numchildren, &numchildren, 1, INT_MAX))
93		tst_brk(TBROK, "Invalid number of children '%s'", str_numchildren);
94
95	if (tst_parse_filesize(str_filesize, &filesize, 1, LLONG_MAX))
96		tst_brk(TBROK, "Invalid file size '%s'", str_filesize);
97
98	if (tst_parse_int(str_numappends, &numappends, 1, INT_MAX))
99		tst_brk(TBROK, "Invalid number of appends '%s'", str_numappends);
100
101	if (tst_parse_int(str_numwrites, &numwrites, 1, INT_MAX))
102		tst_brk(TBROK, "Invalid number of truncate/append '%s'", str_numwrites);
103
104	SAFE_STAT(".", &sb);
105	alignment = sb.st_blksize;
106
107	run_child = SAFE_MMAP(NULL, sizeof(int), PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
108
109	if (numchildren > 2 && !tst_kconfig_check(kconf_rt)) {
110		tst_res(TINFO, "Warning: This test may deadlock on RT kernels");
111		tst_res(TINFO, "If it does, reduce number of threads to 2");
112	}
113}
114
115static void cleanup(void)
116{
117	if (run_child) {
118		*run_child = 0;
119		SAFE_MUNMAP((void *)run_child, sizeof(int));
120	}
121}
122
123static void run(void)
124{
125	char *filename = "file.bin";
126	int wflags = O_DIRECT | O_WRONLY | O_CREAT;
127	int status;
128	int i;
129	int fail = 0;
130
131	*run_child = 1;
132
133	for (i = 0; i < numchildren; i++) {
134		if (!SAFE_FORK()) {
135			dio_read(filename, alignment, filesize);
136			return;
137		}
138	}
139
140	tst_res(TINFO, "Parent writes/truncates the file");
141
142	for (i = 0; i < numwrites; i++) {
143		io_append(filename, 0, wflags, filesize, numappends);
144		SAFE_TRUNCATE(filename, 0);
145		io_append("junkfile", 0xaa, wflags, filesize, numappends);
146		SAFE_TRUNCATE("junkfile", 0);
147
148		if (SAFE_WAITPID(-1, &status, WNOHANG)) {
149			fail = 1;
150			break;
151		}
152
153		if (!tst_remaining_runtime()) {
154			tst_res(TINFO, "Test out of runtime, exiting");
155			break;
156		}
157	}
158
159	if (fail)
160		tst_res(TFAIL, "Non zero bytes read");
161	else
162		tst_res(TPASS, "All bytes read were zeroed");
163
164	*run_child = 0;
165}
166
167static struct tst_test test = {
168	.test_all = run,
169	.setup = setup,
170	.cleanup = cleanup,
171	.needs_tmpdir = 1,
172	.forks_child = 1,
173	.max_runtime = 1800,
174	.options = (struct tst_option[]) {
175		{"n:", &str_numchildren, "Number of threads (default 16)"},
176		{"s:", &str_filesize, "Size of file (default 64K)"},
177		{"a:", &str_numappends, "Number of appends (default 100)"},
178		{"c:", &str_numwrites, "Number of append & truncate (default 100)"},
179		{}
180	},
181	.skip_filesystems = (const char *[]) {
182		"tmpfs",
183		NULL
184	},
185};
186