1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2018 CTERA Networks. All Rights Reserved.
4 * Author: Amir Goldstein <[email protected]>
5 */
6
7 /*\
8 * [Description]
9 *
10 * Check that inotify work for an overlayfs file after copy up and
11 * drop caches.
12 *
13 * An inotify watch pins the file inode in cache, but not the dentry.
14 * The watch will not report events on the file if overlayfs does not
15 * obtain the pinned inode to the new allocated dentry after drop caches.
16 *
17 * The problem has been fixed by commit:
18 * 764baba80168 ("ovl: hash non-dir by lower inode for fsnotify").
19 *
20 * [Algorithm]
21 *
22 * Add watch on an overlayfs lower file then chmod file and drop dentry
23 * and inode caches. Execute operations on file and expect events to be
24 * reported on file watch.
25 */
26
27 #include "config.h"
28
29 #if defined(HAVE_SYS_INOTIFY_H)
30 # include <sys/inotify.h>
31 #endif
32 #include <stdio.h>
33 #include <sys/stat.h>
34 #include <sys/types.h>
35 #include <sys/sysmacros.h>
36 #include <fcntl.h>
37 #include <errno.h>
38 #include <string.h>
39 #include <sys/syscall.h>
40 #include <sys/mount.h>
41 #include <limits.h>
42 #include "tst_test.h"
43 #include "inotify.h"
44
45 #if defined(HAVE_SYS_INOTIFY_H)
46
47 #define EVENT_MAX 1024
48 /* size of the event structure, not counting name */
49 #define EVENT_SIZE (sizeof (struct inotify_event))
50 /* reasonable guess as to size of 1024 events */
51 #define EVENT_BUF_LEN (EVENT_MAX * (EVENT_SIZE + 16))
52
53 #define BUF_SIZE 256
54 static int fd_notify, reap_wd;
55 static int wd;
56
57 struct event_t {
58 unsigned int mask;
59 };
60
61 #define FILE_NAME "test_file"
62 #define FILE_PATH OVL_MNT"/"FILE_NAME
63
64 static const char mntpoint[] = OVL_BASE_MNTPOINT;
65 static struct event_t event_set[EVENT_MAX];
66 static char event_buf[EVENT_BUF_LEN];
67
verify_inotify(void)68 void verify_inotify(void)
69 {
70 int test_cnt = 0;
71
72 /*
73 * generate sequence of events
74 */
75 SAFE_CHMOD(FILE_PATH, 0644);
76 event_set[test_cnt].mask = IN_ATTRIB;
77 test_cnt++;
78
79 SAFE_FILE_PRINTF(FILE_PATH, "1");
80
81 event_set[test_cnt].mask = IN_OPEN;
82 test_cnt++;
83
84 event_set[test_cnt].mask = IN_CLOSE_WRITE;
85 test_cnt++;
86
87 /* Make sure events on upper/lower do not show in overlay watch */
88 SAFE_TOUCH(OVL_LOWER"/"FILE_NAME, 0644, NULL);
89 SAFE_TOUCH(OVL_UPPER"/"FILE_NAME, 0644, NULL);
90
91 int len = read(fd_notify, event_buf, EVENT_BUF_LEN);
92 if (len == -1 && errno != EAGAIN) {
93 tst_brk(TBROK | TERRNO,
94 "read(%d, buf, %zu) failed",
95 fd_notify, EVENT_BUF_LEN);
96 }
97
98 int i = 0, test_num = 0;
99 while (i < len) {
100 struct inotify_event *event;
101 event = (struct inotify_event *)&event_buf[i];
102 if (test_num >= test_cnt) {
103 tst_res(TFAIL,
104 "get unnecessary event: "
105 "wd=%d mask=%08x cookie=%-5u len=%-2u "
106 "name=\"%.*s\"", event->wd, event->mask,
107 event->cookie, event->len, event->len,
108 event->name);
109 } else if (event_set[test_num].mask == event->mask &&
110 !event->len) {
111 tst_res(TPASS,
112 "get event: wd=%d mask=%08x "
113 "cookie=%-5u len=%-2u",
114 event->wd, event->mask,
115 event->cookie, event->len);
116 } else {
117 tst_res(TFAIL, "get event: wd=%d mask=%08x "
118 "(expected %x) cookie=%-5u len=%-2u "
119 "name=\"%.*s\" (expected \"\")",
120 event->wd, event->mask,
121 event_set[test_num].mask,
122 event->cookie, event->len, event->len,
123 event->name);
124 }
125 test_num++;
126 i += EVENT_SIZE + event->len;
127 }
128
129 for (; test_num < test_cnt; test_num++) {
130 tst_res(TFAIL, "didn't get event: mask=%x ",
131 event_set[test_num].mask);
132 }
133 }
134
setup(void)135 static void setup(void)
136 {
137 struct stat buf;
138
139 /* Setup an overlay mount with lower file */
140 SAFE_UMOUNT(OVL_MNT);
141 SAFE_TOUCH(OVL_LOWER"/"FILE_NAME, 0644, NULL);
142 SAFE_MOUNT_OVERLAY();
143
144 fd_notify = SAFE_MYINOTIFY_INIT1(O_NONBLOCK);
145
146 /* Setup a watch on an overlayfs lower file */
147 wd = SAFE_MYINOTIFY_ADD_WATCH(fd_notify, FILE_PATH,
148 IN_ATTRIB | IN_OPEN | IN_CLOSE_WRITE);
149 reap_wd = 1;
150
151 SAFE_STAT(FILE_PATH, &buf);
152 tst_res(TINFO, FILE_PATH " ino=%lu, dev=%u:%u", buf.st_ino,
153 major(buf.st_dev), minor(buf.st_dev));
154
155 /* Drop dentry caches, so overlayfs will allocate a new dentry */
156 SAFE_FILE_PRINTF("/proc/sys/vm/drop_caches", "2");
157
158 /* Copy up file */
159 SAFE_CHMOD(FILE_PATH, 0600);
160
161 /* Lookup file and see if we got the watched file inode number */
162 SAFE_STAT(FILE_PATH, &buf);
163 tst_res(TINFO, FILE_PATH " ino=%lu, dev=%u:%u", buf.st_ino,
164 major(buf.st_dev), minor(buf.st_dev));
165 }
166
cleanup(void)167 static void cleanup(void)
168 {
169 if (reap_wd && myinotify_rm_watch(fd_notify, wd) < 0) {
170 tst_res(TWARN,
171 "inotify_rm_watch (%d, %d) failed,", fd_notify, wd);
172 }
173
174 if (fd_notify > 0)
175 SAFE_CLOSE(fd_notify);
176 }
177
178 static struct tst_test test = {
179 .needs_root = 1,
180 .mount_device = 1,
181 .needs_overlay = 1,
182 .mntpoint = mntpoint,
183 .setup = setup,
184 .cleanup = cleanup,
185 .test_all = verify_inotify,
186 };
187
188 #else
189 TST_TEST_TCONF("system doesn't have required inotify support");
190 #endif
191