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 "common.h"
35
36 static int *run_child;
37
38 static char *str_numchildren;
39 static char *str_filesize;
40 static char *str_numappends;
41 static char *str_numwrites;
42
43 static int numchildren = 16;
44 static long long filesize = 64 * 1024;
45 static long long alignment;
46 static int numappends = 100;
47 static int numwrites = 100;
48
dio_read(const char * filename,long long align,size_t bs)49 static void dio_read(const char *filename, long long align, size_t bs)
50 {
51 int fd;
52 int r;
53 char *bufptr;
54
55 while ((fd = open(filename, O_RDONLY | O_DIRECT, 0666)) < 0)
56 usleep(100);
57
58 bufptr = SAFE_MEMALIGN(align, bs);
59
60 tst_res(TINFO, "child %i reading file", getpid());
61 while (*run_child) {
62 off_t offset;
63 char *bufoff;
64
65 offset = SAFE_LSEEK(fd, SEEK_SET, 0);
66 do {
67 r = read(fd, bufptr, 64 * 1024);
68 if (r > 0) {
69 bufoff = check_zero(bufptr, r);
70 if (bufoff) {
71 tst_res(TINFO, "non-zero read at offset %zu",
72 offset + (bufoff - bufptr));
73 free(bufptr);
74 SAFE_CLOSE(fd);
75 return;
76 }
77 offset += r;
78 }
79 } while (r > 0);
80 }
81
82 free(bufptr);
83 SAFE_CLOSE(fd);
84 }
85
setup(void)86 static void setup(void)
87 {
88 struct stat sb;
89
90 if (tst_parse_int(str_numchildren, &numchildren, 1, INT_MAX))
91 tst_brk(TBROK, "Invalid number of children '%s'", str_numchildren);
92
93 if (tst_parse_filesize(str_filesize, &filesize, 1, LLONG_MAX))
94 tst_brk(TBROK, "Invalid file size '%s'", str_filesize);
95
96 if (tst_parse_int(str_numappends, &numappends, 1, INT_MAX))
97 tst_brk(TBROK, "Invalid number of appends '%s'", str_numappends);
98
99 if (tst_parse_int(str_numwrites, &numwrites, 1, INT_MAX))
100 tst_brk(TBROK, "Invalid number of truncate/append '%s'", str_numwrites);
101
102 SAFE_STAT(".", &sb);
103 alignment = sb.st_blksize;
104
105 run_child = SAFE_MMAP(NULL, sizeof(int), PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
106 }
107
cleanup(void)108 static void cleanup(void)
109 {
110 if (run_child) {
111 *run_child = 0;
112 SAFE_MUNMAP(run_child, sizeof(int));
113 }
114 }
115
run(void)116 static void run(void)
117 {
118 char *filename = "file.bin";
119 int wflags = O_DIRECT | O_WRONLY | O_CREAT;
120 int status;
121 int i;
122 int fail = 0;
123
124 *run_child = 1;
125
126 for (i = 0; i < numchildren; i++) {
127 if (!SAFE_FORK()) {
128 dio_read(filename, alignment, filesize);
129 return;
130 }
131 }
132
133 tst_res(TINFO, "Parent writes/truncates the file");
134
135 for (i = 0; i < numwrites; i++) {
136 io_append(filename, 0, wflags, filesize, numappends);
137 SAFE_TRUNCATE(filename, 0);
138 io_append("junkfile", 0xaa, wflags, filesize, numappends);
139 SAFE_TRUNCATE("junkfile", 0);
140
141 if (SAFE_WAITPID(-1, &status, WNOHANG)) {
142 fail = 1;
143 break;
144 }
145 }
146
147 if (fail)
148 tst_res(TFAIL, "Non zero bytes read");
149 else
150 tst_res(TPASS, "All bytes read were zeroed");
151
152 *run_child = 0;
153 }
154
155 static struct tst_test test = {
156 .test_all = run,
157 .setup = setup,
158 .cleanup = cleanup,
159 .needs_tmpdir = 1,
160 .forks_child = 1,
161 .options = (struct tst_option[]) {
162 {"n:", &str_numchildren, "Number of threads (default 16)"},
163 {"s:", &str_filesize, "Size of file (default 64K)"},
164 {"a:", &str_numappends, "Number of appends (default 100)"},
165 {"c:", &str_numwrites, "Number of append & truncate (default 100)"},
166 {}
167 },
168 .skip_filesystems = (const char *[]) {
169 "tmpfs",
170 NULL
171 },
172 };
173