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1 | /* | |
2 | * Copyright (C) 2008 Intel Corporation | |
3 | * | |
4 | * mdmon socket / message handling | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms and conditions of the GNU General Public License, | |
8 | * version 2, as published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope it will be useful, but WITHOUT | |
11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
13 | * more details. | |
14 | * | |
15 | * You should have received a copy of the GNU General Public License along with | |
16 | * this program; if not, write to the Free Software Foundation, Inc., | |
17 | * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. | |
18 | */ | |
19 | #ifndef _GNU_SOURCE | |
20 | #define _GNU_SOURCE | |
21 | #endif | |
22 | #include <unistd.h> | |
23 | #include <stdio.h> | |
24 | #include <string.h> | |
25 | #include <stdlib.h> | |
26 | #include <errno.h> | |
27 | #include <fcntl.h> | |
28 | #include <sys/types.h> | |
29 | #include <sys/socket.h> | |
30 | #include <sys/un.h> | |
31 | #include "mdadm.h" | |
32 | #include "mdmon.h" | |
33 | ||
34 | static const __u32 start_magic = 0x5a5aa5a5; | |
35 | static const __u32 end_magic = 0xa5a55a5a; | |
36 | ||
37 | static int send_buf(int fd, const void* buf, int len, int tmo) | |
38 | { | |
39 | fd_set set; | |
40 | int rv; | |
41 | struct timeval timeout = {tmo, 0}; | |
42 | struct timeval *ptmo = tmo ? &timeout : NULL; | |
43 | ||
44 | while (len) { | |
45 | FD_ZERO(&set); | |
46 | FD_SET(fd, &set); | |
47 | rv = select(fd+1, NULL, &set, NULL, ptmo); | |
48 | if (rv <= 0) | |
49 | return -1; | |
50 | rv = write(fd, buf, len); | |
51 | if (rv <= 0) | |
52 | return -1; | |
53 | len -= rv; | |
54 | buf += rv; | |
55 | } | |
56 | return 0; | |
57 | } | |
58 | ||
59 | static int recv_buf(int fd, void* buf, int len, int tmo) | |
60 | { | |
61 | fd_set set; | |
62 | int rv; | |
63 | struct timeval timeout = {tmo, 0}; | |
64 | struct timeval *ptmo = tmo ? &timeout : NULL; | |
65 | ||
66 | while (len) { | |
67 | FD_ZERO(&set); | |
68 | FD_SET(fd, &set); | |
69 | rv = select(fd+1, &set, NULL, NULL, ptmo); | |
70 | if (rv <= 0) | |
71 | return -1; | |
72 | rv = read(fd, buf, len); | |
73 | if (rv <= 0) | |
74 | return -1; | |
75 | len -= rv; | |
76 | buf += rv; | |
77 | } | |
78 | return 0; | |
79 | } | |
80 | ||
81 | int send_message(int fd, struct metadata_update *msg, int tmo) | |
82 | { | |
83 | __s32 len = msg->len; | |
84 | int rv; | |
85 | ||
86 | rv = send_buf(fd, &start_magic, 4, tmo); | |
87 | rv = rv ?: send_buf(fd, &len, 4, tmo); | |
88 | if (len > 0) | |
89 | rv = rv ?: send_buf(fd, msg->buf, msg->len, tmo); | |
90 | rv = send_buf(fd, &end_magic, 4, tmo); | |
91 | ||
92 | return rv; | |
93 | } | |
94 | ||
95 | int receive_message(int fd, struct metadata_update *msg, int tmo) | |
96 | { | |
97 | __u32 magic; | |
98 | __s32 len; | |
99 | int rv; | |
100 | ||
101 | rv = recv_buf(fd, &magic, 4, tmo); | |
102 | if (rv < 0 || magic != start_magic) | |
103 | return -1; | |
104 | rv = recv_buf(fd, &len, 4, tmo); | |
105 | if (rv < 0 || len > MSG_MAX_LEN) | |
106 | return -1; | |
107 | if (len > 0) { | |
108 | msg->buf = xmalloc(len); | |
109 | rv = recv_buf(fd, msg->buf, len, tmo); | |
110 | if (rv < 0) { | |
111 | free(msg->buf); | |
112 | return -1; | |
113 | } | |
114 | } else | |
115 | msg->buf = NULL; | |
116 | rv = recv_buf(fd, &magic, 4, tmo); | |
117 | if (rv < 0 || magic != end_magic) { | |
118 | free(msg->buf); | |
119 | return -1; | |
120 | } | |
121 | msg->len = len; | |
122 | return 0; | |
123 | } | |
124 | ||
125 | int ack(int fd, int tmo) | |
126 | { | |
127 | struct metadata_update msg = { .len = 0 }; | |
128 | ||
129 | return send_message(fd, &msg, tmo); | |
130 | } | |
131 | ||
132 | int wait_reply(int fd, int tmo) | |
133 | { | |
134 | struct metadata_update msg; | |
135 | int err = receive_message(fd, &msg, tmo); | |
136 | ||
137 | /* mdmon sent extra data, but caller only cares that we got a | |
138 | * successful reply | |
139 | */ | |
140 | if (err == 0 && msg.len > 0) | |
141 | free(msg.buf); | |
142 | ||
143 | return err; | |
144 | } | |
145 | ||
146 | int connect_monitor(char *devname) | |
147 | { | |
148 | char path[100]; | |
149 | int sfd; | |
150 | long fl; | |
151 | struct sockaddr_un addr; | |
152 | int pos; | |
153 | char *c; | |
154 | ||
155 | pos = sprintf(path, "%s/", MDMON_DIR); | |
156 | if (is_subarray(devname)) { | |
157 | devname++; | |
158 | c = strchr(devname, '/'); | |
159 | if (!c) | |
160 | return -1; | |
161 | snprintf(&path[pos], c - devname + 1, "%s", devname); | |
162 | pos += c - devname; | |
163 | } else | |
164 | pos += sprintf(&path[pos], "%s", devname); | |
165 | sprintf(&path[pos], ".sock"); | |
166 | ||
167 | sfd = socket(PF_LOCAL, SOCK_STREAM, 0); | |
168 | if (sfd < 0) | |
169 | return -1; | |
170 | ||
171 | addr.sun_family = PF_LOCAL; | |
172 | strcpy(addr.sun_path, path); | |
173 | if (connect(sfd, (struct sockaddr*)&addr, sizeof(addr)) < 0) { | |
174 | pr_err("Error connecting monitor with %s: %s\n", | |
175 | addr.sun_path, strerror(errno)); | |
176 | close(sfd); | |
177 | return -1; | |
178 | } | |
179 | ||
180 | fl = fcntl(sfd, F_GETFL, 0); | |
181 | fl |= O_NONBLOCK; | |
182 | fcntl(sfd, F_SETFL, fl); | |
183 | ||
184 | return sfd; | |
185 | } | |
186 | ||
187 | int fping_monitor(int sfd) | |
188 | { | |
189 | int err = 0; | |
190 | ||
191 | if (sfd < 0) | |
192 | return sfd; | |
193 | ||
194 | /* try to ping existing socket */ | |
195 | if (ack(sfd, 20) != 0) | |
196 | err = -1; | |
197 | ||
198 | /* check the reply */ | |
199 | if (!err && wait_reply(sfd, 20) != 0) | |
200 | err = -1; | |
201 | ||
202 | return err; | |
203 | } | |
204 | ||
205 | /* give the monitor a chance to update the metadata */ | |
206 | int ping_monitor(char *devname) | |
207 | { | |
208 | int sfd = connect_monitor(devname); | |
209 | int err; | |
210 | ||
211 | if (sfd >= 0) { | |
212 | err = fping_monitor(sfd); | |
213 | close(sfd); | |
214 | } else | |
215 | err = -1; | |
216 | ||
217 | return err; | |
218 | } | |
219 | ||
220 | static char *ping_monitor_version(char *devname) | |
221 | { | |
222 | int sfd = connect_monitor(devname); | |
223 | struct metadata_update msg; | |
224 | int err = 0; | |
225 | ||
226 | if (sfd < 0) | |
227 | return NULL; | |
228 | ||
229 | if (ack(sfd, 20) != 0) | |
230 | err = -1; | |
231 | ||
232 | if (!err && receive_message(sfd, &msg, 20) != 0) | |
233 | err = -1; | |
234 | ||
235 | close(sfd); | |
236 | ||
237 | if (err || !msg.len || !msg.buf) | |
238 | return NULL; | |
239 | return msg.buf; | |
240 | } | |
241 | ||
242 | int unblock_subarray(struct mdinfo *sra, const int unfreeze) | |
243 | { | |
244 | char buf[64]; | |
245 | int rc = 0; | |
246 | ||
247 | if (sra) { | |
248 | sprintf(buf, "external:%s\n", sra->text_version); | |
249 | buf[9] = '/'; | |
250 | } else | |
251 | buf[9] = '-'; | |
252 | ||
253 | if (buf[9] == '-' || | |
254 | sysfs_set_str(sra, NULL, "metadata_version", buf) || | |
255 | (unfreeze && | |
256 | sysfs_attribute_available(sra, NULL, "sync_action") && | |
257 | sysfs_set_str(sra, NULL, "sync_action", "idle"))) | |
258 | rc = -1; | |
259 | return rc; | |
260 | } | |
261 | ||
262 | int block_subarray(struct mdinfo *sra) | |
263 | { | |
264 | char buf[64]; | |
265 | int rc = 0; | |
266 | ||
267 | sprintf(buf, "external:%s\n", sra->text_version); | |
268 | buf[9] = '-'; | |
269 | if (sysfs_set_str(sra, NULL, "metadata_version", buf)) | |
270 | rc = -1; | |
271 | ||
272 | return rc; | |
273 | } | |
274 | ||
275 | /* check mdmon version if it supports | |
276 | * array blocking mechanism | |
277 | */ | |
278 | int check_mdmon_version(char *container) | |
279 | { | |
280 | char *version = NULL; | |
281 | ||
282 | if (!mdmon_running(container)) { | |
283 | /* if mdmon is not active we assume that any instance that is | |
284 | * later started will match the current mdadm version, if this | |
285 | * assumption is violated we may inadvertantly rebuild an array | |
286 | * that was meant for reshape, or start rebuild on a spare that | |
287 | * was to be moved to another container | |
288 | */ | |
289 | /* pass */; | |
290 | } else { | |
291 | int ver; | |
292 | ||
293 | version = ping_monitor_version(container); | |
294 | ver = version ? mdadm_version(version) : -1; | |
295 | free(version); | |
296 | if (ver < 3002000) { | |
297 | pr_err("mdmon instance for %s cannot be disabled\n", | |
298 | container); | |
299 | return -1; | |
300 | } | |
301 | } | |
302 | ||
303 | return 0; | |
304 | } | |
305 | ||
306 | /** | |
307 | * block_monitor - prevent mdmon spare assignment | |
308 | * @container - container to block | |
309 | * @freeze - flag to additionally freeze sync_action | |
310 | * | |
311 | * This is used by the reshape code to freeze the container, and the | |
312 | * auto-rebuild implementation to atomically move spares. | |
313 | * In both cases we need to stop mdmon from assigning spares to replace | |
314 | * failed devices as we might have other plans for the spare. | |
315 | * For the reshape case we also need to 'freeze' sync_action so that | |
316 | * no recovery happens until we have fully prepared for the reshape. | |
317 | * | |
318 | * We tell mdmon that the array is frozen by marking the 'metadata' name | |
319 | * with a leading '-'. The previously told mdmon "Don't make this array | |
320 | * read/write, leave it readonly". Now it means a more general "Don't | |
321 | * reconfigure this array at all". | |
322 | * As older versions of mdmon (which might run from initrd) don't understand | |
323 | * this, we first check that the running mdmon is new enough. | |
324 | */ | |
325 | int block_monitor(char *container, const int freeze) | |
326 | { | |
327 | struct mdstat_ent *ent, *e, *e2; | |
328 | struct mdinfo *sra = NULL; | |
329 | char buf[64]; | |
330 | int rv = 0; | |
331 | ||
332 | if (check_mdmon_version(container)) | |
333 | return -1; | |
334 | ||
335 | ent = mdstat_read(0, 0); | |
336 | if (!ent) { | |
337 | pr_err("failed to read /proc/mdstat while disabling mdmon\n"); | |
338 | return -1; | |
339 | } | |
340 | ||
341 | /* freeze container contents */ | |
342 | for (e = ent; e; e = e->next) { | |
343 | if (!is_container_member(e, container)) | |
344 | continue; | |
345 | sysfs_free(sra); | |
346 | sra = sysfs_read(-1, e->devnm, GET_VERSION); | |
347 | if (!sra) { | |
348 | pr_err("failed to read sysfs for subarray%s\n", | |
349 | to_subarray(e, container)); | |
350 | break; | |
351 | } | |
352 | /* can't reshape an array that we can't monitor */ | |
353 | if (sra->text_version[0] == '-') | |
354 | break; | |
355 | ||
356 | if (freeze && sysfs_freeze_array(sra) < 1) | |
357 | break; | |
358 | /* flag this array to not be modified by mdmon (close race with | |
359 | * takeover in reshape case and spare reassignment in the | |
360 | * auto-rebuild case) | |
361 | */ | |
362 | if (block_subarray(sra)) | |
363 | break; | |
364 | ping_monitor(container); | |
365 | ||
366 | /* check that we did not race with recovery */ | |
367 | if ((freeze && | |
368 | !sysfs_attribute_available(sra, NULL, "sync_action")) || | |
369 | (freeze && | |
370 | sysfs_attribute_available(sra, NULL, "sync_action") && | |
371 | sysfs_get_str(sra, NULL, "sync_action", buf, 20) > 0 && | |
372 | strcmp(buf, "frozen\n") == 0)) | |
373 | /* pass */; | |
374 | else { | |
375 | unblock_subarray(sra, 0); | |
376 | break; | |
377 | } | |
378 | /* Double check against races - there should be no spares | |
379 | * or part-spares | |
380 | */ | |
381 | sysfs_free(sra); | |
382 | sra = sysfs_read(-1, e->devnm, GET_DEVS | GET_STATE); | |
383 | if (sra && sra->array.spare_disks > 0) { | |
384 | unblock_subarray(sra, freeze); | |
385 | break; | |
386 | } | |
387 | } | |
388 | ||
389 | if (e) { | |
390 | pr_err("failed to freeze subarray%s\n", | |
391 | to_subarray(e, container)); | |
392 | ||
393 | /* thaw the partially frozen container */ | |
394 | for (e2 = ent; e2 && e2 != e; e2 = e2->next) { | |
395 | if (!is_container_member(e2, container)) | |
396 | continue; | |
397 | sysfs_free(sra); | |
398 | sra = sysfs_read(-1, e2->devnm, GET_VERSION); | |
399 | if (unblock_subarray(sra, freeze)) | |
400 | pr_err("Failed to unfreeze %s\n", e2->devnm); | |
401 | } | |
402 | ||
403 | ping_monitor(container); /* cleared frozen */ | |
404 | rv = -1; | |
405 | } | |
406 | ||
407 | sysfs_free(sra); | |
408 | free_mdstat(ent); | |
409 | ||
410 | return rv; | |
411 | } | |
412 | ||
413 | void unblock_monitor(char *container, const int unfreeze) | |
414 | { | |
415 | struct mdstat_ent *ent, *e; | |
416 | struct mdinfo *sra = NULL; | |
417 | int to_ping = 0; | |
418 | ||
419 | ent = mdstat_read(0, 0); | |
420 | if (!ent) { | |
421 | pr_err("failed to read /proc/mdstat while unblocking container\n"); | |
422 | return; | |
423 | } | |
424 | ||
425 | /* unfreeze container contents */ | |
426 | for (e = ent; e; e = e->next) { | |
427 | if (!is_container_member(e, container)) | |
428 | continue; | |
429 | sysfs_free(sra); | |
430 | sra = sysfs_read(-1, e->devnm, GET_VERSION|GET_LEVEL); | |
431 | if (!sra) | |
432 | continue; | |
433 | if (sra->array.level > 0) | |
434 | to_ping++; | |
435 | if (unblock_subarray(sra, unfreeze)) | |
436 | pr_err("Failed to unfreeze %s\n", e->devnm); | |
437 | } | |
438 | if (to_ping) | |
439 | ping_monitor(container); | |
440 | ||
441 | sysfs_free(sra); | |
442 | free_mdstat(ent); | |
443 | } | |
444 | ||
445 | /* give the manager a chance to view the updated container state. This | |
446 | * would naturally happen due to the manager noticing a change in | |
447 | * /proc/mdstat; however, pinging encourages this detection to happen | |
448 | * while an exclusive open() on the container is active | |
449 | */ | |
450 | int ping_manager(char *devname) | |
451 | { | |
452 | int sfd = connect_monitor(devname); | |
453 | struct metadata_update msg = { .len = -1 }; | |
454 | int err = 0; | |
455 | ||
456 | if (sfd < 0) | |
457 | return sfd; | |
458 | ||
459 | err = send_message(sfd, &msg, 20); | |
460 | ||
461 | /* check the reply */ | |
462 | if (!err && wait_reply(sfd, 20) != 0) | |
463 | err = -1; | |
464 | ||
465 | close(sfd); | |
466 | return err; | |
467 | } | |
468 | ||
469 | /* using takeover operation for grow purposes, mdadm has to be sure | |
470 | * that mdmon processes all updates, and if necessary it will be closed | |
471 | * at takeover to raid0 operation | |
472 | */ | |
473 | void flush_mdmon(char *container) | |
474 | { | |
475 | ping_manager(container); | |
476 | ping_monitor(container); | |
477 | } |