2 * mdmon - monitor external metadata arrays
4 * Copyright (C) 2007-2008 Neil Brown <neilb@suse.de>
5 * Copyright (C) 2007-2008 Intel Corporation
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.
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
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.
23 #include <sys/syscall.h>
24 #include <sys/select.h>
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
34 static int write_attr(char *attr, int fd)
36 return write(fd, attr, strlen(attr));
39 static void add_fd(fd_set *fds, int *maxfd, int fd)
48 static int read_attr(char *buf, int len, int fd)
57 n = read(fd, buf, len - 1);
69 int get_resync_start(struct active_array *a)
74 n = read_attr(buf, 30, a->resync_start_fd);
78 a->resync_start = strtoull(buf, NULL, 10);
84 static enum array_state read_state(int fd)
87 int n = read_attr(buf, 20, fd);
91 return (enum array_state) sysfs_match_word(buf, array_states);
94 static enum sync_action read_action( int fd)
97 int n = read_attr(buf, 20, fd);
101 return (enum sync_action) sysfs_match_word(buf, sync_actions);
104 int read_dev_state(int fd)
107 int n = read_attr(buf, 60, fd);
116 if (sysfs_attr_match(cp, "faulty"))
118 if (sysfs_attr_match(cp, "in_sync"))
120 if (sysfs_attr_match(cp, "write_mostly"))
121 rv |= DS_WRITE_MOSTLY;
122 if (sysfs_attr_match(cp, "spare"))
124 if (sysfs_attr_match(cp, "blocked"))
126 cp = strchr(cp, ',');
133 static void signal_manager(void)
135 /* tgkill(getpid(), mon_tid, SIGUSR1); */
137 syscall(SYS_tgkill, pid, mgr_tid, SIGUSR1);
140 /* Monitor a set of active md arrays - all of which share the
141 * same metadata - and respond to events that require
144 * New arrays are detected by another thread which allocates
145 * required memory and attaches the data structure to our list.
149 * This is detected by array_state going to 'clear' or 'inactive'.
150 * while we thought it was active.
151 * Response is to mark metadata as clean and 'clear' the array(??)
153 * array_state if 'write-pending'
154 * We mark metadata as 'dirty' then set array to 'active'.
156 * Either ignore, or mark clean, then mark metadata as clean.
159 * detected by rd-N/state reporting "faulty"
160 * mark device as 'failed' in metadata, let the kernel release the
161 * device by writing '-blocked' to rd/state, and finally write 'remove' to
162 * rd/state. Before a disk can be replaced it must be failed and removed
163 * from all container members, this will be preemptive for the other
167 * sync_action was 'resync' and becomes 'idle' and resync_start becomes
169 * Notify metadata that sync is complete.
172 * sync_action changes from 'recover' to 'idle'
173 * Check each device state and mark metadata if 'faulty' or 'in_sync'.
176 * This only happens on finding a new array... mdadm will have set
177 * 'resync_start' to the correct value. If 'resync_start' indicates that an
178 * resync needs to occur set the array to the 'active' state rather than the
179 * initial read-auto state.
183 * We wait for a change (poll/select) on array_state, sync_action, and
184 * each rd-X/state file.
185 * When we get any change, we check everything. So read each state file,
186 * then decide what to do.
188 * The core action is to write new metadata to all devices in the array.
189 * This is done at most once on any wakeup.
190 * After that we might:
191 * - update the array_state
192 * - set the role of some devices.
193 * - request a sync_action
197 static int read_and_act(struct active_array *a)
199 int check_degraded = 0;
203 a->next_state = bad_word;
204 a->next_action = bad_action;
206 a->curr_state = read_state(a->info.state_fd);
207 a->curr_action = read_action(a->action_fd);
208 for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
210 if (mdi->state_fd >= 0)
211 mdi->curr_state = read_dev_state(mdi->state_fd);
214 if (a->curr_state <= inactive &&
215 a->prev_state > inactive) {
216 /* array has been stopped */
218 a->container->ss->set_array_state(a, 1);
219 a->next_state = clear;
222 if (a->curr_state == write_pending) {
224 a->container->ss->set_array_state(a, 0);
225 a->next_state = active;
227 if (a->curr_state == active_idle) {
228 /* Set array to 'clean' FIRST, then mark clean
231 a->next_state = clean;
233 if (a->curr_state == clean) {
235 a->container->ss->set_array_state(a, 1);
238 if (a->curr_state == readonly) {
239 /* Well, I'm ready to handle things. If readonly
240 * wasn't requested, transition to read-auto.
243 read_attr(buf, sizeof(buf), a->metadata_fd);
244 if (strncmp(buf, "external:-", 10) == 0) {
245 /* explicit request for readonly array. Leave it alone */
249 if (a->container->ss->set_array_state(a, 2))
250 a->next_state = read_auto; /* array is clean */
252 a->next_state = active; /* Now active for recovery etc */
257 a->curr_action == idle &&
258 a->prev_action == resync) {
259 /* A resync has finished. The endpoint is recorded in
260 * 'sync_start'. We don't update the metadata
261 * until the array goes inactive or readonly though.
262 * Just check if we need to fiddle spares.
265 a->container->ss->set_array_state(a, a->curr_state <= clean);
270 a->curr_action == idle &&
271 a->prev_action == recover) {
272 /* A recovery has finished. Some disks may be in sync now,
273 * and the array may no longer be degraded
275 for (mdi = a->info.devs ; mdi ; mdi = mdi->next) {
276 a->container->ss->set_disk(a, mdi->disk.raid_disk,
278 if (! (mdi->curr_state & DS_INSYNC))
283 /* Check for failures and if found:
284 * 1/ Record the failure in the metadata and unblock the device.
285 * FIXME update the kernel to stop notifying on failed drives when
286 * the array is readonly and we have cleared 'blocked'
287 * 2/ Try to remove the device if the array is writable, or can be
290 for (mdi = a->info.devs ; mdi ; mdi = mdi->next) {
291 if (mdi->curr_state & DS_FAULTY) {
292 a->container->ss->set_disk(a, mdi->disk.raid_disk,
295 mdi->next_state |= DS_UNBLOCK;
296 if (a->curr_state == read_auto) {
297 a->container->ss->set_array_state(a, 0);
298 a->next_state = active;
300 if (a->curr_state > readonly)
301 mdi->next_state |= DS_REMOVE;
305 a->container->ss->sync_metadata(a->container);
306 dprintf("%s(%d): state:%s action:%s next(", __func__, a->info.container_member,
307 array_states[a->curr_state], sync_actions[a->curr_action]);
309 /* Effect state changes in the array */
310 if (a->next_state != bad_word) {
311 dprintf(" state:%s", array_states[a->next_state]);
312 write_attr(array_states[a->next_state], a->info.state_fd);
314 if (a->next_action != bad_action) {
315 write_attr(sync_actions[a->next_action], a->action_fd);
316 dprintf(" action:%s", sync_actions[a->next_action]);
318 for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
319 if (mdi->next_state & DS_UNBLOCK) {
320 dprintf(" %d:-blocked", mdi->disk.raid_disk);
321 write_attr("-blocked", mdi->state_fd);
324 if ((mdi->next_state & DS_REMOVE) && mdi->state_fd >= 0) {
327 /* the kernel may not be able to immediately remove the
328 * disk, we can simply wait until the next event to try
331 remove_result = write_attr("remove", mdi->state_fd);
332 if (remove_result > 0) {
333 dprintf(" %d:removed", mdi->disk.raid_disk);
334 close(mdi->state_fd);
338 if (mdi->next_state & DS_INSYNC) {
339 write_attr("+in_sync", mdi->state_fd);
340 dprintf(" %d:+in_sync", mdi->disk.raid_disk);
345 /* move curr_ to prev_ */
346 a->prev_state = a->curr_state;
348 a->prev_action = a->curr_action;
350 for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
351 mdi->prev_state = mdi->curr_state;
355 if (check_degraded) {
356 /* manager will do the actual check */
357 a->check_degraded = 1;
367 static struct mdinfo *
368 find_device(struct active_array *a, int major, int minor)
372 for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
373 if (mdi->disk.major == major && mdi->disk.minor == minor)
379 static void reconcile_failed(struct active_array *aa, struct mdinfo *failed)
381 struct active_array *a;
382 struct mdinfo *victim;
384 for (a = aa; a; a = a->next) {
387 victim = find_device(a, failed->disk.major, failed->disk.minor);
391 if (!(victim->curr_state & DS_FAULTY))
392 write_attr("faulty", victim->state_fd);
397 static void dprint_wake_reasons(fd_set *fds)
405 fprintf(stderr, "monitor: wake ( ");
406 for (i = 0; i < FD_SETSIZE; i++) {
407 if (FD_ISSET(i, fds)) {
408 sprintf(proc_path, "/proc/%d/fd/%d",
411 rv = readlink(proc_path, link, sizeof(link) - 1);
413 fprintf(stderr, "%d:unknown ", i);
417 basename = strrchr(link, '/');
418 fprintf(stderr, "%d:%s ",
419 i, basename ? ++basename : link);
422 fprintf(stderr, ")\n");
426 int monitor_loop_cnt;
428 static int wait_and_act(struct supertype *container, int nowait)
432 struct active_array **aap = &container->arrays;
433 struct active_array *a, **ap;
436 static unsigned int dirty_arrays = ~0; /* start at some non-zero value */
440 for (ap = aap ; *ap ;) {
442 /* once an array has been deactivated we want to
443 * ask the manager to discard it.
457 add_fd(&rfds, &maxfd, a->info.state_fd);
458 add_fd(&rfds, &maxfd, a->action_fd);
459 for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
460 add_fd(&rfds, &maxfd, mdi->state_fd);
465 if (manager_ready && (*aap == NULL || (sigterm && !dirty_arrays))) {
466 /* No interesting arrays, or we have been told to
467 * terminate and everything is clean. Lets see about
468 * exiting. Note that blocking at this point is not a
469 * problem as there are no active arrays, there is
470 * nothing that we need to be ready to do.
472 int fd = open(container->device_name, O_RDONLY|O_EXCL);
473 if (fd >= 0 || errno != EBUSY) {
474 /* OK, we are safe to leave */
475 if (sigterm && !dirty_arrays)
476 dprintf("caught sigterm, all clean... exiting\n");
478 dprintf("no arrays to monitor... exiting\n");
479 remove_pidfile(container->devname);
488 sigprocmask(SIG_UNBLOCK, NULL, &set);
489 sigdelset(&set, SIGUSR1);
490 monitor_loop_cnt |= 1;
491 rv = pselect(maxfd+1, &rfds, NULL, NULL, NULL, &set);
492 monitor_loop_cnt += 1;
493 if (rv == -1 && errno == EINTR)
496 dprint_wake_reasons(&rfds);
502 struct metadata_update *this;
504 for (this = update_queue; this ; this = this->next)
505 container->ss->process_update(container, this);
507 update_queue_handled = update_queue;
510 container->ss->sync_metadata(container);
515 for (a = *aap; a ; a = a->next) {
518 if (a->replaces && !discard_this) {
519 struct active_array **ap;
520 for (ap = &a->next; *ap && *ap != a->replaces;
525 discard_this = a->replaces;
527 /* FIXME check if device->state_fd need to be cleared?*/
531 rv += read_and_act(a);
535 /* when terminating stop manipulating the array after it is
536 * clean, but make sure read_and_act() is given a chance to
537 * handle 'active_idle'
539 switch (read_state(a->info.state_fd)) {
547 if (a->curr_state == active_idle)
553 dirty_arrays += is_dirty;
554 if (sigterm && !is_dirty)
555 a->container = NULL; /* stop touching this array */
558 /* propagate failures across container members */
559 for (a = *aap; a ; a = a->next) {
562 for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
563 if (mdi->curr_state & DS_FAULTY)
564 reconcile_failed(*aap, mdi);
570 void do_monitor(struct supertype *container)
575 rv = wait_and_act(container, first);