summaryrefslogtreecommitdiff
path: root/src/readahead/readahead-replay.c
blob: f46dc3baeb9f37e302fdc9341eb445e5fbc722bc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/

/***
  This file is part of systemd.

  Copyright 2010 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <errno.h>
#include <inttypes.h>
#include <fcntl.h>
#include <linux/limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <getopt.h>
#include <sys/inotify.h>

#include <systemd/sd-daemon.h>

#include "missing.h"
#include "util.h"
#include "set.h"
#include "ioprio.h"
#include "readahead-common.h"
#include "virt.h"

static ReadaheadShared *shared = NULL;

static int unpack_file(FILE *pack) {
        _cleanup_close_ int fd = -1;
        char fn[PATH_MAX];
        bool any = false;
        struct stat st;
        uint64_t inode;

        assert(pack);

        if (!fgets(fn, sizeof(fn), pack))
                return 0;

        char_array_0(fn);
        truncate_nl(fn);

        fd = open(fn, O_RDONLY|O_CLOEXEC|O_NOATIME|O_NOCTTY|O_NOFOLLOW);
        if (fd < 0) {
                if (errno != ENOENT && errno != EPERM && errno != EACCES && errno != ELOOP)
                        log_warning("open(%s) failed: %m", fn);

        } else if (file_verify(fd, fn, arg_file_size_max, &st) <= 0)
                fd = safe_close(fd);

        if (fread(&inode, sizeof(inode), 1, pack) != 1) {
                log_error("Premature end of pack file.");
                return -EIO;
        }

        if (fd >= 0) {
                /* If the inode changed the file got deleted, so just
                 * ignore this entry */
                if (st.st_ino != (uint64_t) inode)
                        fd = safe_close(fd);
        }

        for (;;) {
                uint32_t b, c;

                if (fread(&b, sizeof(b), 1, pack) != 1 ||
                    fread(&c, sizeof(c), 1, pack) != 1) {
                        log_error("Premature end of pack file.");
                        return -EIO;
                }

                if (b == 0 && c == 0)
                        break;

                if (c <= b) {
                        log_error("Invalid pack file.");
                        return -EIO;
                }

                log_debug("%s: page %u to %u", fn, b, c);

                any = true;

                if (fd >= 0) {
                        if (posix_fadvise(fd, b * page_size(), (c - b) * page_size(), POSIX_FADV_WILLNEED) < 0) {
                                log_warning("posix_fadvise() failed: %m");
                                return -errno;
                        }
                }
        }

        if (!any && fd >= 0) {
                /* if no range is encoded in the pack file this is
                 * intended to mean that the whole file shall be
                 * read */

                if (posix_fadvise(fd, 0, st.st_size, POSIX_FADV_WILLNEED) < 0) {
                        log_warning("posix_fadvise() failed: %m");
                        return -errno;
                }
        }

        return 0;
}

static int replay(const char *root) {
        _cleanup_close_ int inotify_fd = -1;
        _cleanup_free_ char *pack_fn = NULL;
        _cleanup_fclose_ FILE *pack = NULL;
        bool on_ssd, ready = false;
        char line[LINE_MAX];
        int prio, c;

        assert(root);

        block_bump_request_nr(root);

        if (asprintf(&pack_fn, "%s/.readahead", root) < 0)
                return log_oom();

        pack = fopen(pack_fn, "re");
        if (!pack) {
                if (errno == ENOENT) {
                        log_debug("No pack file found.");
                        return 0;
                }

                log_error("Failed to open pack file: %m");
                return -errno;
        }

        posix_fadvise(fileno(pack), 0, 0, POSIX_FADV_WILLNEED);

        inotify_fd = open_inotify();
        if (inotify_fd < 0)
                return inotify_fd;

        if (!fgets(line, sizeof(line), pack)) {
                log_error("Premature end of pack file.");
                return -EIO;
        }

        char_array_0(line);

        if (!streq(line, CANONICAL_HOST READAHEAD_PACK_FILE_VERSION)) {
                log_debug("Pack file host or version type mismatch.");
                goto done;
        }

        c = getc(pack);
        if (c == EOF) {
                log_debug("Premature end of pack file.");
                return -EIO;
        }

        /* We do not retest SSD here, so that we can start replaying
         * before udev is up.*/
        on_ssd = c == 'S';
        log_debug("On SSD: %s", yes_no(on_ssd));

        if (on_ssd)
                prio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0);
        else
                /* We are not using RT here, since we'd starve IO that
                we didn't record (which is for example blkid, since
                its disk accesses go directly to the block device and
                are thus not visible in fallocate) to death. However,
                we do ask for an IO prio that is slightly higher than
                the default (which is BE. 4) */
                prio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 2);

        if (ioprio_set(IOPRIO_WHO_PROCESS, getpid(), prio) < 0)
                log_warning("Failed to set IDLE IO priority class: %m");

        sd_notify(0, "STATUS=Replaying readahead data");

        log_debug("Replaying...");

        if (access("/run/systemd/readahead/noreplay", F_OK) >= 0) {
                log_debug("Got termination request");
                goto done;
        }

        while (!feof(pack) && !ferror(pack)) {
                uint8_t inotify_buffer[sizeof(struct inotify_event) + FILENAME_MAX];
                int k;
                ssize_t n;

                n = read(inotify_fd, &inotify_buffer, sizeof(inotify_buffer));
                if (n < 0) {
                        if (errno != EINTR && errno != EAGAIN) {
                                log_error("Failed to read inotify event: %m");
                                return -errno;
                        }
                } else {
                        struct inotify_event *e = (struct inotify_event*) inotify_buffer;

                        while (n > 0) {
                                size_t step;

                                if ((e->mask & IN_CREATE) && streq(e->name, "noreplay")) {
                                        log_debug("Got termination request");
                                        goto done;
                                }

                                step = sizeof(struct inotify_event) + e->len;
                                assert(step <= (size_t) n);

                                e = (struct inotify_event*) ((uint8_t*) e + step);
                                n -= step;
                        }
                }

                k = unpack_file(pack);
                if (k < 0)
                        return k;

                if (!ready) {
                        /* We delay the ready notification until we
                         * queued at least one read */
                        sd_notify(0, "READY=1");
                        ready = true;
                }
        }

done:
        if (ferror(pack)) {
                log_error("Failed to read pack file.");
                return -EIO;
        }

        if (!ready)
                sd_notify(0, "READY=1");

        log_debug("Done.");
        return 0;
}

int main_replay(const char *root) {

        if (!root)
                root = "/";

        if (!enough_ram()) {
                log_info("Disabling readahead replay due to low memory.");
                return EXIT_SUCCESS;
        }

        shared = shared_get();
        if (!shared)
                return EXIT_FAILURE;

        shared->replay = getpid();
        __sync_synchronize();

        if (replay(root) < 0)
                return EXIT_FAILURE;

        return EXIT_SUCCESS;
}