blob: dd111870beee0c2796abcb1b8b0960695d789914 [file] [log] [blame]
Thomas Gleixner43aa3132019-05-29 07:17:54 -07001// SPDX-License-Identifier: GPL-2.0-only
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -07002/*
3 * An implementation of the host initiated guest snapshot for Hyper-V.
4 *
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -07005 * Copyright (C) 2013, Microsoft, Inc.
6 * Author : K. Y. Srinivasan <kys@microsoft.com>
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -07007 */
8
9
10#include <sys/types.h>
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070011#include <sys/poll.h>
Olaf Hering7b413b62013-04-24 07:48:52 -070012#include <sys/ioctl.h>
Alex Ngea81fdf2017-08-06 13:12:52 -070013#include <sys/stat.h>
Dexuan Cui1330fc32018-03-04 22:17:14 -070014#include <sys/sysmacros.h>
Olaf Hering7b413b62013-04-24 07:48:52 -070015#include <fcntl.h>
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070016#include <stdio.h>
Olaf Heringd3d1ee32013-04-24 07:48:51 -070017#include <mntent.h>
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070018#include <stdlib.h>
19#include <unistd.h>
20#include <string.h>
21#include <ctype.h>
22#include <errno.h>
Olaf Hering7b413b62013-04-24 07:48:52 -070023#include <linux/fs.h>
Alex Ngea81fdf2017-08-06 13:12:52 -070024#include <linux/major.h>
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070025#include <linux/hyperv.h>
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070026#include <syslog.h>
Vitaly Kuznetsov170f4be2014-10-22 18:07:11 +020027#include <getopt.h>
Vitaly Kuznetsov07136792018-06-05 13:37:56 -070028#include <stdbool.h>
29#include <dirent.h>
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -070030
Dexuan Cui9fc3c012020-01-25 21:49:41 -080031static bool fs_frozen;
32
Dexuan Cui4f689192014-09-25 21:52:04 -070033/* Don't use syslog() in the function since that can cause write to disk */
34static int vss_do_freeze(char *dir, unsigned int cmd)
Olaf Hering7b413b62013-04-24 07:48:52 -070035{
36 int ret, fd = open(dir, O_RDONLY);
37
38 if (fd < 0)
39 return 1;
Dexuan Cui4f689192014-09-25 21:52:04 -070040
Olaf Hering7b413b62013-04-24 07:48:52 -070041 ret = ioctl(fd, cmd, 0);
Dexuan Cui4f689192014-09-25 21:52:04 -070042
43 /*
44 * If a partition is mounted more than once, only the first
45 * FREEZE/THAW can succeed and the later ones will get
46 * EBUSY/EINVAL respectively: there could be 2 cases:
Adrian Vladu2d35c662019-05-06 16:51:24 +000047 * 1) a user may mount the same partition to different directories
Dexuan Cui4f689192014-09-25 21:52:04 -070048 * by mistake or on purpose;
49 * 2) The subvolume of btrfs appears to have the same partition
50 * mounted more than once.
51 */
52 if (ret) {
53 if ((cmd == FIFREEZE && errno == EBUSY) ||
54 (cmd == FITHAW && errno == EINVAL)) {
55 close(fd);
56 return 0;
57 }
58 }
59
Olaf Hering7b413b62013-04-24 07:48:52 -070060 close(fd);
61 return !!ret;
62}
63
Vitaly Kuznetsov07136792018-06-05 13:37:56 -070064static bool is_dev_loop(const char *blkname)
65{
66 char *buffer;
67 DIR *dir;
68 struct dirent *entry;
69 bool ret = false;
70
71 buffer = malloc(PATH_MAX);
72 if (!buffer) {
73 syslog(LOG_ERR, "Can't allocate memory!");
74 exit(1);
75 }
76
77 snprintf(buffer, PATH_MAX, "%s/loop", blkname);
78 if (!access(buffer, R_OK | X_OK)) {
79 ret = true;
80 goto free_buffer;
81 } else if (errno != ENOENT) {
82 syslog(LOG_ERR, "Can't access: %s; error:%d %s!",
83 buffer, errno, strerror(errno));
84 }
85
86 snprintf(buffer, PATH_MAX, "%s/slaves", blkname);
87 dir = opendir(buffer);
88 if (!dir) {
89 if (errno != ENOENT)
90 syslog(LOG_ERR, "Can't opendir: %s; error:%d %s!",
91 buffer, errno, strerror(errno));
92 goto free_buffer;
93 }
94
95 while ((entry = readdir(dir)) != NULL) {
96 if (strcmp(entry->d_name, ".") == 0 ||
97 strcmp(entry->d_name, "..") == 0)
98 continue;
99
100 snprintf(buffer, PATH_MAX, "%s/slaves/%s", blkname,
101 entry->d_name);
102 if (is_dev_loop(buffer)) {
103 ret = true;
104 break;
105 }
106 }
107 closedir(dir);
108free_buffer:
109 free(buffer);
110 return ret;
111}
112
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700113static int vss_operate(int operation)
114{
Olaf Heringd3d1ee32013-04-24 07:48:51 -0700115 char match[] = "/dev/";
116 FILE *mounts;
117 struct mntent *ent;
Alex Ngea81fdf2017-08-06 13:12:52 -0700118 struct stat sb;
Vaughan Cao4ce50e92015-03-18 12:29:28 -0700119 char errdir[1024] = {0};
Vitaly Kuznetsov07136792018-06-05 13:37:56 -0700120 char blkdir[23]; /* /sys/dev/block/XXX:XXX */
Olaf Hering7b413b62013-04-24 07:48:52 -0700121 unsigned int cmd;
Vitaly Kuznetsov7a401742014-11-10 17:37:01 +0100122 int error = 0, root_seen = 0, save_errno = 0;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700123
124 switch (operation) {
125 case VSS_OP_FREEZE:
Olaf Hering7b413b62013-04-24 07:48:52 -0700126 cmd = FIFREEZE;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700127 break;
128 case VSS_OP_THAW:
Olaf Hering7b413b62013-04-24 07:48:52 -0700129 cmd = FITHAW;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700130 break;
Olaf Heringeb8905b2013-04-24 07:48:48 -0700131 default:
132 return -1;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700133 }
134
Olaf Heringd3d1ee32013-04-24 07:48:51 -0700135 mounts = setmntent("/proc/mounts", "r");
136 if (mounts == NULL)
Olaf Heringeb8905b2013-04-24 07:48:48 -0700137 return -1;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700138
K. Y. Srinivasan0e272632013-04-24 07:48:54 -0700139 while ((ent = getmntent(mounts))) {
Olaf Heringd3d1ee32013-04-24 07:48:51 -0700140 if (strncmp(ent->mnt_fsname, match, strlen(match)))
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700141 continue;
Vitaly Kuznetsov07136792018-06-05 13:37:56 -0700142 if (stat(ent->mnt_fsname, &sb)) {
143 syslog(LOG_ERR, "Can't stat: %s; error:%d %s!",
144 ent->mnt_fsname, errno, strerror(errno));
145 } else {
146 sprintf(blkdir, "/sys/dev/block/%d:%d",
147 major(sb.st_rdev), minor(sb.st_rdev));
148 if (is_dev_loop(blkdir))
149 continue;
150 }
Vitaly Kuznetsov9e5db052014-11-10 17:37:02 +0100151 if (hasmntopt(ent, MNTOPT_RO) != NULL)
Olaf Hering10b637b2013-04-24 07:48:53 -0700152 continue;
K. Y. Srinivasanf33b2152014-02-12 08:40:22 -0800153 if (strcmp(ent->mnt_type, "vfat") == 0)
154 continue;
Olaf Heringd3d1ee32013-04-24 07:48:51 -0700155 if (strcmp(ent->mnt_dir, "/") == 0) {
156 root_seen = 1;
157 continue;
158 }
Dexuan Cui4f689192014-09-25 21:52:04 -0700159 error |= vss_do_freeze(ent->mnt_dir, cmd);
Dexuan Cui9fc3c012020-01-25 21:49:41 -0800160 if (operation == VSS_OP_FREEZE) {
161 if (error)
162 goto err;
163 fs_frozen = true;
164 }
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700165 }
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700166
Vaughan Cao4ce50e92015-03-18 12:29:28 -0700167 endmntent(mounts);
168
Olaf Heringd3d1ee32013-04-24 07:48:51 -0700169 if (root_seen) {
Dexuan Cui4f689192014-09-25 21:52:04 -0700170 error |= vss_do_freeze("/", cmd);
Dexuan Cui9fc3c012020-01-25 21:49:41 -0800171 if (operation == VSS_OP_FREEZE) {
172 if (error)
173 goto err;
174 fs_frozen = true;
175 }
Olaf Heringd3d1ee32013-04-24 07:48:51 -0700176 }
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700177
Dexuan Cui9fc3c012020-01-25 21:49:41 -0800178 if (operation == VSS_OP_THAW && !error)
179 fs_frozen = false;
180
Vitaly Kuznetsov7a401742014-11-10 17:37:01 +0100181 goto out;
Dexuan Cui4f689192014-09-25 21:52:04 -0700182err:
Vitaly Kuznetsov7a401742014-11-10 17:37:01 +0100183 save_errno = errno;
Vaughan Cao4ce50e92015-03-18 12:29:28 -0700184 if (ent) {
185 strncpy(errdir, ent->mnt_dir, sizeof(errdir)-1);
186 endmntent(mounts);
187 }
Dexuan Cui4f689192014-09-25 21:52:04 -0700188 vss_operate(VSS_OP_THAW);
Dexuan Cui9fc3c012020-01-25 21:49:41 -0800189 fs_frozen = false;
Vitaly Kuznetsov7a401742014-11-10 17:37:01 +0100190 /* Call syslog after we thaw all filesystems */
191 if (ent)
192 syslog(LOG_ERR, "FREEZE of %s failed; error:%d %s",
Vaughan Cao4ce50e92015-03-18 12:29:28 -0700193 errdir, save_errno, strerror(save_errno));
Vitaly Kuznetsov7a401742014-11-10 17:37:01 +0100194 else
195 syslog(LOG_ERR, "FREEZE of / failed; error:%d %s", save_errno,
196 strerror(save_errno));
197out:
Dexuan Cui4f689192014-09-25 21:52:04 -0700198 return error;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700199}
200
Vitaly Kuznetsov170f4be2014-10-22 18:07:11 +0200201void print_usage(char *argv[])
202{
203 fprintf(stderr, "Usage: %s [options]\n"
204 "Options are:\n"
205 " -n, --no-daemon stay in foreground, don't daemonize\n"
206 " -h, --help print this help\n", argv[0]);
207}
208
209int main(int argc, char *argv[])
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700210{
Dexuan Cui9fc3c012020-01-25 21:49:41 -0800211 int vss_fd = -1, len;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700212 int error;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700213 struct pollfd pfd;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700214 int op;
Vitaly Kuznetsovf5722b92015-04-11 18:07:56 -0700215 struct hv_vss_msg vss_msg[1];
Vitaly Kuznetsov170f4be2014-10-22 18:07:11 +0200216 int daemonize = 1, long_index = 0, opt;
Dexuan Cui9fc3c012020-01-25 21:49:41 -0800217 int in_handshake;
Vitaly Kuznetsovcd8dc052015-04-11 18:07:57 -0700218 __u32 kernel_modver;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700219
Vitaly Kuznetsov170f4be2014-10-22 18:07:11 +0200220 static struct option long_options[] = {
221 {"help", no_argument, 0, 'h' },
222 {"no-daemon", no_argument, 0, 'n' },
223 {0, 0, 0, 0 }
224 };
225
226 while ((opt = getopt_long(argc, argv, "hn", long_options,
227 &long_index)) != -1) {
228 switch (opt) {
229 case 'n':
230 daemonize = 0;
231 break;
232 case 'h':
Adrian Vladub0995152019-05-06 16:50:58 +0000233 print_usage(argv);
234 exit(0);
Vitaly Kuznetsov170f4be2014-10-22 18:07:11 +0200235 default:
236 print_usage(argv);
237 exit(EXIT_FAILURE);
238 }
239 }
240
241 if (daemonize && daemon(1, 0))
Olaf Heringeb8905b2013-04-24 07:48:48 -0700242 return 1;
243
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700244 openlog("Hyper-V VSS", 0, LOG_USER);
245 syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
246
Dexuan Cui9fc3c012020-01-25 21:49:41 -0800247reopen_vss_fd:
248 if (vss_fd != -1)
249 close(vss_fd);
250 if (fs_frozen) {
251 if (vss_operate(VSS_OP_THAW) || fs_frozen) {
252 syslog(LOG_ERR, "failed to thaw file system: err=%d",
253 errno);
254 exit(EXIT_FAILURE);
255 }
256 }
257
258 in_handshake = 1;
Vitaly Kuznetsovf5722b92015-04-11 18:07:56 -0700259 vss_fd = open("/dev/vmbus/hv_vss", O_RDWR);
260 if (vss_fd < 0) {
261 syslog(LOG_ERR, "open /dev/vmbus/hv_vss failed; error: %d %s",
262 errno, strerror(errno));
Tomas Hozzad12e1462013-06-27 13:52:48 +0200263 exit(EXIT_FAILURE);
264 }
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700265 /*
266 * Register ourselves with the kernel.
267 */
Vitaly Kuznetsovf5722b92015-04-11 18:07:56 -0700268 vss_msg->vss_hdr.operation = VSS_OP_REGISTER1;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700269
Vitaly Kuznetsovf5722b92015-04-11 18:07:56 -0700270 len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700271 if (len < 0) {
Vitaly Kuznetsovf5722b92015-04-11 18:07:56 -0700272 syslog(LOG_ERR, "registration to kernel failed; error: %d %s",
273 errno, strerror(errno));
274 close(vss_fd);
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700275 exit(EXIT_FAILURE);
276 }
277
Vitaly Kuznetsovf5722b92015-04-11 18:07:56 -0700278 pfd.fd = vss_fd;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700279
280 while (1) {
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700281 pfd.events = POLLIN;
282 pfd.revents = 0;
Tomas Hozza9561d472013-06-27 13:52:49 +0200283
284 if (poll(&pfd, 1, -1) < 0) {
285 syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
286 if (errno == EINVAL) {
Vitaly Kuznetsovf5722b92015-04-11 18:07:56 -0700287 close(vss_fd);
Tomas Hozza9561d472013-06-27 13:52:49 +0200288 exit(EXIT_FAILURE);
289 }
290 else
291 continue;
292 }
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700293
Vitaly Kuznetsovf5722b92015-04-11 18:07:56 -0700294 len = read(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700295
Vitaly Kuznetsovcd8dc052015-04-11 18:07:57 -0700296 if (in_handshake) {
297 if (len != sizeof(kernel_modver)) {
298 syslog(LOG_ERR, "invalid version negotiation");
299 exit(EXIT_FAILURE);
300 }
301 kernel_modver = *(__u32 *)vss_msg;
302 in_handshake = 0;
303 syslog(LOG_INFO, "VSS: kernel module version: %d",
304 kernel_modver);
305 continue;
306 }
307
Vitaly Kuznetsovf5722b92015-04-11 18:07:56 -0700308 if (len != sizeof(struct hv_vss_msg)) {
309 syslog(LOG_ERR, "read failed; error:%d %s",
310 errno, strerror(errno));
Dexuan Cui9fc3c012020-01-25 21:49:41 -0800311 goto reopen_vss_fd;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700312 }
313
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700314 op = vss_msg->vss_hdr.operation;
315 error = HV_S_OK;
316
317 switch (op) {
318 case VSS_OP_FREEZE:
319 case VSS_OP_THAW:
320 error = vss_operate(op);
Dexuan Cui4f689192014-09-25 21:52:04 -0700321 syslog(LOG_INFO, "VSS: op=%s: %s\n",
322 op == VSS_OP_FREEZE ? "FREEZE" : "THAW",
323 error ? "failed" : "succeeded");
324
325 if (error) {
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700326 error = HV_E_FAIL;
Dexuan Cui4f689192014-09-25 21:52:04 -0700327 syslog(LOG_ERR, "op=%d failed!", op);
328 syslog(LOG_ERR, "report it with these files:");
329 syslog(LOG_ERR, "/etc/fstab and /proc/mounts");
330 }
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700331 break;
Alex Ngdb886e42016-09-02 05:58:25 -0700332 case VSS_OP_HOT_BACKUP:
333 syslog(LOG_INFO, "VSS: op=CHECK HOT BACKUP\n");
334 break;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700335 default:
336 syslog(LOG_ERR, "Illegal op:%d\n", op);
337 }
Dexuan Cui9fc3c012020-01-25 21:49:41 -0800338
339 /*
340 * The write() may return an error due to the faked VSS_OP_THAW
341 * message upon hibernation. Ignore the error by resetting the
342 * dev file, i.e. closing and re-opening it.
343 */
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700344 vss_msg->error = error;
Dexuan Cuia689d252015-12-14 16:01:58 -0800345 len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
Vitaly Kuznetsovf5722b92015-04-11 18:07:56 -0700346 if (len != sizeof(struct hv_vss_msg)) {
347 syslog(LOG_ERR, "write failed; error: %d %s", errno,
348 strerror(errno));
Dexuan Cui9fc3c012020-01-25 21:49:41 -0800349 goto reopen_vss_fd;
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700350 }
351 }
352
Vitaly Kuznetsovf5722b92015-04-11 18:07:56 -0700353 close(vss_fd);
354 exit(0);
K. Y. Srinivasan96dd86f2013-03-15 12:30:06 -0700355}