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1 /*
2 * mdmon - monitor external metadata arrays
3 *
4 * Copyright (C) 2007-2009 Neil Brown <neilb@suse.de>
5 * Copyright (C) 2007-2009 Intel Corporation
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms and conditions of the GNU General Public License,
9 * version 2, as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * more details.
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
19 */
20
21 #include "mdadm.h"
22 #include "mdmon.h"
23 #include <sys/syscall.h>
24 #include <sys/select.h>
25 #include <signal.h>
26
27 static char *array_states[] = {
28 "clear", "inactive", "suspended", "readonly", "read-auto",
29 "clean", "active", "write-pending", "active-idle", NULL };
30 static char *sync_actions[] = {
31 "idle", "reshape", "resync", "recover", "check", "repair", NULL
32 };
33
34 static int write_attr(char *attr, int fd)
35 {
36 return write(fd, attr, strlen(attr));
37 }
38
39 static void add_fd(fd_set *fds, int *maxfd, int fd)
40 {
41 if (fd < 0)
42 return;
43 if (fd > *maxfd)
44 *maxfd = fd;
45 FD_SET(fd, fds);
46 }
47
48 static int read_attr(char *buf, int len, int fd)
49 {
50 int n;
51
52 if (fd < 0) {
53 buf[0] = 0;
54 return 0;
55 }
56 lseek(fd, 0, 0);
57 n = read(fd, buf, len - 1);
58
59 if (n <= 0) {
60 buf[0] = 0;
61 return 0;
62 }
63 buf[n] = 0;
64 if (buf[n-1] == '\n')
65 buf[n-1] = 0;
66 return n;
67 }
68
69 static unsigned long long read_resync_start(int fd)
70 {
71 char buf[30];
72 int n;
73
74 n = read_attr(buf, 30, fd);
75 if (n <= 0)
76 return 0;
77 if (strncmp(buf, "none", 4) == 0)
78 return MaxSector;
79 else
80 return strtoull(buf, NULL, 10);
81 }
82
83 static unsigned long long read_sync_completed(int fd)
84 {
85 unsigned long long val;
86 char buf[50];
87 int n;
88 char *ep;
89
90 n = read_attr(buf, 50, fd);
91
92 if (n <= 0)
93 return 0;
94 buf[n] = 0;
95 val = strtoull(buf, &ep, 0);
96 if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))
97 return 0;
98 return val;
99 }
100
101 static enum array_state read_state(int fd)
102 {
103 char buf[20];
104 int n = read_attr(buf, 20, fd);
105
106 if (n <= 0)
107 return bad_word;
108 return (enum array_state) sysfs_match_word(buf, array_states);
109 }
110
111 static enum sync_action read_action( int fd)
112 {
113 char buf[20];
114 int n = read_attr(buf, 20, fd);
115
116 if (n <= 0)
117 return bad_action;
118 return (enum sync_action) sysfs_match_word(buf, sync_actions);
119 }
120
121 int read_dev_state(int fd)
122 {
123 char buf[60];
124 int n = read_attr(buf, 60, fd);
125 char *cp;
126 int rv = 0;
127
128 if (n <= 0)
129 return 0;
130
131 cp = buf;
132 while (cp) {
133 if (sysfs_attr_match(cp, "faulty"))
134 rv |= DS_FAULTY;
135 if (sysfs_attr_match(cp, "in_sync"))
136 rv |= DS_INSYNC;
137 if (sysfs_attr_match(cp, "write_mostly"))
138 rv |= DS_WRITE_MOSTLY;
139 if (sysfs_attr_match(cp, "spare"))
140 rv |= DS_SPARE;
141 if (sysfs_attr_match(cp, "blocked"))
142 rv |= DS_BLOCKED;
143 cp = strchr(cp, ',');
144 if (cp)
145 cp++;
146 }
147 return rv;
148 }
149
150 static void signal_manager(void)
151 {
152 /* tgkill(getpid(), mon_tid, SIGUSR1); */
153 int pid = getpid();
154 syscall(SYS_tgkill, pid, mgr_tid, SIGUSR1);
155 }
156
157 /* Monitor a set of active md arrays - all of which share the
158 * same metadata - and respond to events that require
159 * metadata update.
160 *
161 * New arrays are detected by another thread which allocates
162 * required memory and attaches the data structure to our list.
163 *
164 * Events:
165 * Array stops.
166 * This is detected by array_state going to 'clear' or 'inactive'.
167 * while we thought it was active.
168 * Response is to mark metadata as clean and 'clear' the array(??)
169 * write-pending
170 * array_state if 'write-pending'
171 * We mark metadata as 'dirty' then set array to 'active'.
172 * active_idle
173 * Either ignore, or mark clean, then mark metadata as clean.
174 *
175 * device fails
176 * detected by rd-N/state reporting "faulty"
177 * mark device as 'failed' in metadata, let the kernel release the
178 * device by writing '-blocked' to rd/state, and finally write 'remove' to
179 * rd/state. Before a disk can be replaced it must be failed and removed
180 * from all container members, this will be preemptive for the other
181 * arrays... safe?
182 *
183 * sync completes
184 * sync_action was 'resync' and becomes 'idle' and resync_start becomes
185 * MaxSector
186 * Notify metadata that sync is complete.
187 *
188 * recovery completes
189 * sync_action changes from 'recover' to 'idle'
190 * Check each device state and mark metadata if 'faulty' or 'in_sync'.
191 *
192 * deal with resync
193 * This only happens on finding a new array... mdadm will have set
194 * 'resync_start' to the correct value. If 'resync_start' indicates that an
195 * resync needs to occur set the array to the 'active' state rather than the
196 * initial read-auto state.
197 *
198 *
199 *
200 * We wait for a change (poll/select) on array_state, sync_action, and
201 * each rd-X/state file.
202 * When we get any change, we check everything. So read each state file,
203 * then decide what to do.
204 *
205 * The core action is to write new metadata to all devices in the array.
206 * This is done at most once on any wakeup.
207 * After that we might:
208 * - update the array_state
209 * - set the role of some devices.
210 * - request a sync_action
211 *
212 */
213
214 static int read_and_act(struct active_array *a)
215 {
216 unsigned long long sync_completed;
217 int check_degraded = 0;
218 int check_reshape = 0;
219 int deactivate = 0;
220 struct mdinfo *mdi;
221 int dirty = 0;
222 int count = 0;
223
224 a->next_state = bad_word;
225 a->next_action = bad_action;
226
227 a->curr_state = read_state(a->info.state_fd);
228 a->curr_action = read_action(a->action_fd);
229 a->info.resync_start = read_resync_start(a->resync_start_fd);
230 sync_completed = read_sync_completed(a->sync_completed_fd);
231 for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
232 mdi->next_state = 0;
233 mdi->curr_state = 0;
234 if (mdi->state_fd >= 0) {
235 mdi->recovery_start = read_resync_start(mdi->recovery_fd);
236 mdi->curr_state = read_dev_state(mdi->state_fd);
237 }
238 }
239
240 if (a->curr_state > inactive &&
241 a->prev_state == inactive) {
242 /* array has been started
243 * possible that container operation has to be completed
244 */
245 a->container->ss->set_array_state(a, 0);
246 }
247 if (a->curr_state <= inactive &&
248 a->prev_state > inactive) {
249 /* array has been stopped */
250 a->container->ss->set_array_state(a, 1);
251 a->next_state = clear;
252 deactivate = 1;
253 }
254 if (a->curr_state == write_pending) {
255 a->container->ss->set_array_state(a, 0);
256 a->next_state = active;
257 dirty = 1;
258 }
259 if (a->curr_state == active_idle) {
260 /* Set array to 'clean' FIRST, then mark clean
261 * in the metadata
262 */
263 a->next_state = clean;
264 dirty = 1;
265 }
266 if (a->curr_state == clean) {
267 a->container->ss->set_array_state(a, 1);
268 }
269 if (a->curr_state == active ||
270 a->curr_state == suspended ||
271 a->curr_state == bad_word)
272 dirty = 1;
273 if (a->curr_state == readonly) {
274 /* Well, I'm ready to handle things. If readonly
275 * wasn't requested, transition to read-auto.
276 */
277 char buf[64];
278 read_attr(buf, sizeof(buf), a->metadata_fd);
279 if (strncmp(buf, "external:-", 10) == 0) {
280 /* explicit request for readonly array. Leave it alone */
281 ;
282 } else {
283 if (a->container->ss->set_array_state(a, 2))
284 a->next_state = read_auto; /* array is clean */
285 else {
286 a->next_state = active; /* Now active for recovery etc */
287 dirty = 1;
288 }
289 }
290 }
291
292 if (!deactivate &&
293 a->curr_action == idle &&
294 a->prev_action == resync) {
295 /* A resync has finished. The endpoint is recorded in
296 * 'sync_start'. We don't update the metadata
297 * until the array goes inactive or readonly though.
298 * Just check if we need to fiddle spares.
299 */
300 a->container->ss->set_array_state(a, a->curr_state <= clean);
301 check_degraded = 1;
302 }
303
304 if (!deactivate &&
305 a->curr_action == idle &&
306 a->prev_action == recover) {
307 /* A recovery has finished. Some disks may be in sync now,
308 * and the array may no longer be degraded
309 */
310 for (mdi = a->info.devs ; mdi ; mdi = mdi->next) {
311 a->container->ss->set_disk(a, mdi->disk.raid_disk,
312 mdi->curr_state);
313 if (! (mdi->curr_state & DS_INSYNC))
314 check_degraded = 1;
315 count++;
316 }
317 if (count != a->info.array.raid_disks)
318 check_degraded = 1;
319 }
320
321 if (!deactivate &&
322 a->curr_action == reshape &&
323 a->prev_action != reshape)
324 /* reshape was requested by mdadm. Need to see if
325 * new devices have been added. Manager does that
326 * when it sees check_reshape
327 */
328 check_reshape = 1;
329
330 /* Check for failures and if found:
331 * 1/ Record the failure in the metadata and unblock the device.
332 * FIXME update the kernel to stop notifying on failed drives when
333 * the array is readonly and we have cleared 'blocked'
334 * 2/ Try to remove the device if the array is writable, or can be
335 * made writable.
336 */
337 for (mdi = a->info.devs ; mdi ; mdi = mdi->next) {
338 if (mdi->curr_state & DS_FAULTY) {
339 a->container->ss->set_disk(a, mdi->disk.raid_disk,
340 mdi->curr_state);
341 check_degraded = 1;
342 mdi->next_state |= DS_UNBLOCK;
343 if (a->curr_state == read_auto) {
344 a->container->ss->set_array_state(a, 0);
345 a->next_state = active;
346 }
347 if (a->curr_state > readonly)
348 mdi->next_state |= DS_REMOVE;
349 }
350 }
351
352 /* Check for recovery checkpoint notifications. We need to be a
353 * minimum distance away from the last checkpoint to prevent
354 * over checkpointing. Note reshape checkpointing is handled
355 * in the second branch.
356 */
357 if (sync_completed > a->last_checkpoint &&
358 sync_completed - a->last_checkpoint > a->info.component_size >> 4 &&
359 a->curr_action > reshape) {
360 /* A (non-reshape) sync_action has reached a checkpoint.
361 * Record the updated position in the metadata
362 */
363 a->last_checkpoint = sync_completed;
364 a->container->ss->set_array_state(a, a->curr_state <= clean);
365 } else if ((a->curr_action == idle && a->prev_action == reshape) ||
366 (a->curr_action == reshape
367 && sync_completed > a->last_checkpoint) ) {
368 /* Reshape has progressed or completed so we need to
369 * update the array state - and possibly the array size
370 */
371 if (sync_completed != 0)
372 a->last_checkpoint = sync_completed;
373 /* We might need to update last_checkpoint depending on
374 * the reason that reshape finished.
375 * if array reshape is really finished:
376 * set check point to the end, this allows
377 * set_array_state() to finalize reshape in metadata
378 * if reshape if broken: do not set checkpoint to the end
379 * this allows for reshape restart from checkpoint
380 */
381 if ((a->curr_action != reshape) &&
382 (a->prev_action == reshape)) {
383 char buf[40];
384 if ((sysfs_get_str(&a->info, NULL,
385 "reshape_position",
386 buf,
387 sizeof(buf)) >= 0) &&
388 strncmp(buf, "none", 4) == 0)
389 a->last_checkpoint = a->info.component_size;
390 }
391 a->container->ss->set_array_state(a, a->curr_state <= clean);
392 a->last_checkpoint = sync_completed;
393 }
394
395 if (sync_completed > a->last_checkpoint)
396 a->last_checkpoint = sync_completed;
397
398 a->container->ss->sync_metadata(a->container);
399 dprintf("%s(%d): state:%s action:%s next(", __func__, a->info.container_member,
400 array_states[a->curr_state], sync_actions[a->curr_action]);
401
402 /* Effect state changes in the array */
403 if (a->next_state != bad_word) {
404 dprintf(" state:%s", array_states[a->next_state]);
405 write_attr(array_states[a->next_state], a->info.state_fd);
406 }
407 if (a->next_action != bad_action) {
408 write_attr(sync_actions[a->next_action], a->action_fd);
409 dprintf(" action:%s", sync_actions[a->next_action]);
410 }
411 for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
412 if (mdi->next_state & DS_UNBLOCK) {
413 dprintf(" %d:-blocked", mdi->disk.raid_disk);
414 write_attr("-blocked", mdi->state_fd);
415 }
416
417 if ((mdi->next_state & DS_REMOVE) && mdi->state_fd >= 0) {
418 int remove_result;
419
420 /* the kernel may not be able to immediately remove the
421 * disk, we can simply wait until the next event to try
422 * again.
423 */
424 remove_result = write_attr("remove", mdi->state_fd);
425 if (remove_result > 0) {
426 dprintf(" %d:removed", mdi->disk.raid_disk);
427 close(mdi->state_fd);
428 close(mdi->recovery_fd);
429 mdi->state_fd = -1;
430 }
431 }
432 if (mdi->next_state & DS_INSYNC) {
433 write_attr("+in_sync", mdi->state_fd);
434 dprintf(" %d:+in_sync", mdi->disk.raid_disk);
435 }
436 }
437 dprintf(" )\n");
438
439 /* move curr_ to prev_ */
440 a->prev_state = a->curr_state;
441
442 a->prev_action = a->curr_action;
443
444 for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
445 mdi->prev_state = mdi->curr_state;
446 mdi->next_state = 0;
447 }
448
449 if (check_degraded || check_reshape) {
450 /* manager will do the actual check */
451 if (check_degraded)
452 a->check_degraded = 1;
453 if (check_reshape)
454 a->check_reshape = 1;
455 signal_manager();
456 }
457
458 if (deactivate)
459 a->container = NULL;
460
461 return dirty;
462 }
463
464 static struct mdinfo *
465 find_device(struct active_array *a, int major, int minor)
466 {
467 struct mdinfo *mdi;
468
469 for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
470 if (mdi->disk.major == major && mdi->disk.minor == minor)
471 return mdi;
472
473 return NULL;
474 }
475
476 static void reconcile_failed(struct active_array *aa, struct mdinfo *failed)
477 {
478 struct active_array *a;
479 struct mdinfo *victim;
480
481 for (a = aa; a; a = a->next) {
482 if (!a->container || a->to_remove)
483 continue;
484 victim = find_device(a, failed->disk.major, failed->disk.minor);
485 if (!victim)
486 continue;
487
488 if (!(victim->curr_state & DS_FAULTY))
489 write_attr("faulty", victim->state_fd);
490 }
491 }
492
493 #ifdef DEBUG
494 static void dprint_wake_reasons(fd_set *fds)
495 {
496 int i;
497 char proc_path[256];
498 char link[256];
499 char *basename;
500 int rv;
501
502 fprintf(stderr, "monitor: wake ( ");
503 for (i = 0; i < FD_SETSIZE; i++) {
504 if (FD_ISSET(i, fds)) {
505 sprintf(proc_path, "/proc/%d/fd/%d",
506 (int) getpid(), i);
507
508 rv = readlink(proc_path, link, sizeof(link) - 1);
509 if (rv < 0) {
510 fprintf(stderr, "%d:unknown ", i);
511 continue;
512 }
513 link[rv] = '\0';
514 basename = strrchr(link, '/');
515 fprintf(stderr, "%d:%s ",
516 i, basename ? ++basename : link);
517 }
518 }
519 fprintf(stderr, ")\n");
520 }
521 #endif
522
523 int monitor_loop_cnt;
524
525 static int wait_and_act(struct supertype *container, int nowait)
526 {
527 fd_set rfds;
528 int maxfd = 0;
529 struct active_array **aap = &container->arrays;
530 struct active_array *a, **ap;
531 int rv;
532 struct mdinfo *mdi;
533 static unsigned int dirty_arrays = ~0; /* start at some non-zero value */
534
535 FD_ZERO(&rfds);
536
537 for (ap = aap ; *ap ;) {
538 a = *ap;
539 /* once an array has been deactivated we want to
540 * ask the manager to discard it.
541 */
542 if (!a->container || a->to_remove) {
543 if (discard_this) {
544 ap = &(*ap)->next;
545 continue;
546 }
547 *ap = a->next;
548 a->next = NULL;
549 discard_this = a;
550 signal_manager();
551 continue;
552 }
553
554 add_fd(&rfds, &maxfd, a->info.state_fd);
555 add_fd(&rfds, &maxfd, a->action_fd);
556 add_fd(&rfds, &maxfd, a->sync_completed_fd);
557 for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
558 add_fd(&rfds, &maxfd, mdi->state_fd);
559
560 ap = &(*ap)->next;
561 }
562
563 if (manager_ready && (*aap == NULL || (sigterm && !dirty_arrays))) {
564 /* No interesting arrays, or we have been told to
565 * terminate and everything is clean. Lets see about
566 * exiting. Note that blocking at this point is not a
567 * problem as there are no active arrays, there is
568 * nothing that we need to be ready to do.
569 */
570 int fd;
571 if (sigterm)
572 fd = open_dev_excl(container->devnum);
573 else
574 fd = open_dev_flags(container->devnum, O_RDONLY|O_EXCL);
575 if (fd >= 0 || errno != EBUSY) {
576 /* OK, we are safe to leave */
577 if (sigterm && !dirty_arrays)
578 dprintf("caught sigterm, all clean... exiting\n");
579 else
580 dprintf("no arrays to monitor... exiting\n");
581 if (!sigterm)
582 /* On SIGTERM, someone (the take-over mdmon) will
583 * clean up
584 */
585 remove_pidfile(container->devname);
586 exit_now = 1;
587 signal_manager();
588 close(fd);
589 exit(0);
590 }
591 }
592
593 if (!nowait) {
594 sigset_t set;
595 struct timespec ts;
596 ts.tv_sec = 24*3600;
597 ts.tv_nsec = 0;
598 if (*aap == NULL) {
599 /* just waiting to get O_EXCL access */
600 ts.tv_sec = 0;
601 ts.tv_nsec = 20000000ULL;
602 }
603 sigprocmask(SIG_UNBLOCK, NULL, &set);
604 sigdelset(&set, SIGUSR1);
605 monitor_loop_cnt |= 1;
606 rv = pselect(maxfd+1, NULL, NULL, &rfds, &ts, &set);
607 monitor_loop_cnt += 1;
608 if (rv == -1 && errno == EINTR)
609 rv = 0;
610 #ifdef DEBUG
611 dprint_wake_reasons(&rfds);
612 #endif
613
614 }
615
616 if (update_queue) {
617 struct metadata_update *this;
618
619 for (this = update_queue; this ; this = this->next)
620 container->ss->process_update(container, this);
621
622 update_queue_handled = update_queue;
623 update_queue = NULL;
624 signal_manager();
625 container->ss->sync_metadata(container);
626 }
627
628 rv = 0;
629 dirty_arrays = 0;
630 for (a = *aap; a ; a = a->next) {
631 int is_dirty;
632
633 if (a->replaces && !discard_this) {
634 struct active_array **ap;
635 for (ap = &a->next; *ap && *ap != a->replaces;
636 ap = & (*ap)->next)
637 ;
638 if (*ap)
639 *ap = (*ap)->next;
640 discard_this = a->replaces;
641 a->replaces = NULL;
642 /* FIXME check if device->state_fd need to be cleared?*/
643 signal_manager();
644 }
645 if (a->container && !a->to_remove) {
646 is_dirty = read_and_act(a);
647 rv |= 1;
648 dirty_arrays += is_dirty;
649 /* when terminating stop manipulating the array after it
650 * is clean, but make sure read_and_act() is given a
651 * chance to handle 'active_idle'
652 */
653 if (sigterm && !is_dirty)
654 a->container = NULL; /* stop touching this array */
655 }
656 }
657
658 /* propagate failures across container members */
659 for (a = *aap; a ; a = a->next) {
660 if (!a->container || a->to_remove)
661 continue;
662 for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
663 if (mdi->curr_state & DS_FAULTY)
664 reconcile_failed(*aap, mdi);
665 }
666
667 return rv;
668 }
669
670 void do_monitor(struct supertype *container)
671 {
672 int rv;
673 int first = 1;
674 do {
675 rv = wait_and_act(container, first);
676 first = 0;
677 } while (rv >= 0);
678 }