handle disk failures
[thirdparty/mdadm.git] / monitor.c
CommitLineData
549e9569
NB
1
2#include "mdadm.h"
3#include "mdmon.h"
4
5#include <sys/select.h>
6
7
8static char *array_states[] = {
9 "clear", "inactive", "suspended", "readonly", "read-auto",
10 "clean", "active", "write-pending", "active-idle", NULL };
11static char *sync_actions[] = {
12 "idle", "reshape", "resync", "recover", "check", "repair", NULL
13};
14
15static int write_attr(char *attr, int fd)
16{
17 return write(fd, attr, strlen(attr));
18}
19
20static void add_fd(fd_set *fds, int *maxfd, int fd)
21{
22 if (fd < 0)
23 return;
24 if (fd > *maxfd)
25 *maxfd = fd;
26 FD_SET(fd, fds);
27}
28
29static int read_attr(char *buf, int len, int fd)
30{
31 int n;
32
33 if (fd < 0) {
34 buf[0] = 0;
35 return 0;
36 }
37 lseek(fd, 0, 0);
38 n = read(fd, buf, len - 1);
39
40 if (n <= 0) {
41 buf[0] = 0;
42 return 0;
43 }
44 buf[n] = 0;
45 if (buf[n-1] == '\n')
46 buf[n-1] = 0;
47 return n;
48}
49
50static int get_sync_pos(struct active_array *a)
51{
52 char buf[30];
53 int n;
54
55 n = read_attr(buf, 30, a->sync_pos_fd);
56 if (n <= 0)
57 return n;
58
59 if (strncmp(buf, "max", 3) == 0) {
60 a->sync_pos = ~(unsigned long long)0;
61 return 1;
62 }
63 a->sync_pos = strtoull(buf, NULL, 10);
64 return 1;
65}
66
c052ba30
DW
67static int get_resync_start(struct active_array *a)
68{
69 char buf[30];
70 int n;
71
72 n = read_attr(buf, 30, a->resync_start_fd);
73 if (n <= 0)
74 return n;
75
76 a->resync_start = strtoull(buf, NULL, 10);
77
78 return 1;
79}
549e9569
NB
80
81static int attr_match(const char *attr, const char *str)
82{
83 /* See if attr, read from a sysfs file, matches
84 * str. They must either be the same, or attr can
85 * have a trailing newline or comma
86 */
87 while (*attr && *str && *attr == *str) {
88 attr++;
89 str++;
90 }
91
92 if (*str || (*attr && *attr != ',' && *attr != '\n'))
93 return 0;
94 return 1;
95}
96
97static int match_word(const char *word, char **list)
98{
99 int n;
100 for (n=0; list[n]; n++)
101 if (attr_match(word, list[n]))
102 break;
103 return n;
104}
105
106static enum array_state read_state(int fd)
107{
108 char buf[20];
109 int n = read_attr(buf, 20, fd);
110
111 if (n <= 0)
112 return bad_word;
113 return (enum array_state) match_word(buf, array_states);
114}
115
116static enum sync_action read_action( int fd)
117{
118 char buf[20];
119 int n = read_attr(buf, 20, fd);
120
121 if (n <= 0)
122 return bad_action;
123 return (enum sync_action) match_word(buf, sync_actions);
124}
125
549e9569
NB
126int read_dev_state(int fd)
127{
128 char buf[60];
129 int n = read_attr(buf, 60, fd);
130 char *cp;
131 int rv = 0;
132
133 if (n <= 0)
134 return 0;
135
136 cp = buf;
137 while (cp) {
8d45d196 138 if (attr_match(cp, "faulty"))
549e9569 139 rv |= DS_FAULTY;
8d45d196 140 if (attr_match(cp, "in_sync"))
549e9569 141 rv |= DS_INSYNC;
8d45d196 142 if (attr_match(cp, "write_mostly"))
549e9569 143 rv |= DS_WRITE_MOSTLY;
8d45d196 144 if (attr_match(cp, "spare"))
549e9569 145 rv |= DS_SPARE;
8d45d196
DW
146 if (attr_match(cp, "blocked"))
147 rv |= DS_BLOCKED;
549e9569
NB
148 cp = strchr(cp, ',');
149 if (cp)
150 cp++;
151 }
152 return rv;
153}
154
155
156/* Monitor a set of active md arrays - all of which share the
157 * same metadata - and respond to events that require
158 * metadata update.
159 *
160 * New arrays are detected by another thread which allocates
161 * required memory and attaches the data structure to our list.
162 *
163 * Events:
164 * Array stops.
165 * This is detected by array_state going to 'clear' or 'inactive'.
166 * while we thought it was active.
167 * Response is to mark metadata as clean and 'clear' the array(??)
168 * write-pending
169 * array_state if 'write-pending'
170 * We mark metadata as 'dirty' then set array to 'active'.
171 * active_idle
172 * Either ignore, or mark clean, then mark metadata as clean.
173 *
174 * device fails
175 * detected by rd-N/state reporting "faulty"
8d45d196
DW
176 * mark device as 'failed' in metadata, let the kernel release the
177 * device by writing '-blocked' to rd/state, and finally write 'remove' to
178 * rd/state
549e9569
NB
179 *
180 * sync completes
181 * sync_action was 'resync' and becomes 'idle' and resync_start becomes
182 * MaxSector
183 * Notify metadata that sync is complete.
184 * "Deal with Degraded"
185 *
186 * recovery completes
187 * sync_action changes from 'recover' to 'idle'
188 * Check each device state and mark metadata if 'faulty' or 'in_sync'.
189 * "Deal with Degraded"
190 *
191 * deal with degraded array
192 * We only do this when first noticing the array is degraded.
193 * This can be when we first see the array, when sync completes or
194 * when recovery completes.
195 *
196 * Check if number of failed devices suggests recovery is needed, and
197 * skip if not.
198 * Ask metadata for a spare device
199 * Add device as not in_sync and give a role
200 * Update metadata.
201 * Start recovery.
202 *
203 * deal with resync
c052ba30
DW
204 * This only happens on finding a new array... mdadm will have set
205 * 'resync_start' to the correct value. If 'resync_start' indicates that an
206 * resync needs to occur set the array to the 'active' state rather than the
207 * initial read-auto state.
549e9569
NB
208 *
209 *
210 *
211 * We wait for a change (poll/select) on array_state, sync_action, and
212 * each rd-X/state file.
213 * When we get any change, we check everything. So read each state file,
214 * then decide what to do.
215 *
216 * The core action is to write new metadata to all devices in the array.
217 * This is done at most once on any wakeup.
218 * After that we might:
219 * - update the array_state
220 * - set the role of some devices.
221 * - request a sync_action
222 *
223 */
224
225static int read_and_act(struct active_array *a)
226{
227 int check_degraded;
2a0bb19e 228 int deactivate = 0;
549e9569
NB
229 struct mdinfo *mdi;
230
231 a->next_state = bad_word;
232 a->next_action = bad_action;
233
234 a->curr_state = read_state(a->info.state_fd);
235 a->curr_action = read_action(a->action_fd);
236 for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
237 mdi->next_state = 0;
8d45d196
DW
238 if (mdi->state_fd > 0)
239 mdi->curr_state = read_dev_state(mdi->state_fd);
549e9569
NB
240 }
241
242 if (a->curr_state <= inactive &&
243 a->prev_state > inactive) {
244 /* array has been stopped */
245 get_sync_pos(a);
246 a->container->ss->mark_clean(a, a->sync_pos);
247 a->next_state = clear;
2a0bb19e 248 deactivate = 1;
549e9569
NB
249 }
250 if (a->curr_state == write_pending) {
251 a->container->ss->mark_dirty(a);
252 a->next_state = active;
253 }
254 if (a->curr_state == active_idle) {
255 /* Set array to 'clean' FIRST, then
256 * a->ss->mark_clean(a);
257 * just ignore for now.
258 */
259 }
260
261 if (a->curr_state == readonly) {
262 /* Well, I'm ready to handle things, so
263 * read-auto is OK. FIXME what if we really want
264 * readonly ???
265 */
c052ba30
DW
266 get_resync_start(a);
267 if (a->resync_start == ~0ULL)
268 a->next_state = read_auto; /* array is clean */
269 else {
270 a->container->ss->mark_dirty(a);
271 a->next_state = active;
272 }
549e9569
NB
273 }
274
275 if (a->curr_action == idle &&
276 a->prev_action == resync) {
fd7cde1b
DW
277 /* check resync_start to see if it is 'max' */
278 get_resync_start(a);
279 a->container->ss->mark_sync(a, a->resync_start);
549e9569
NB
280 check_degraded = 1;
281 }
282
283 if (a->curr_action == idle &&
284 a->prev_action == recover) {
285 for (mdi = a->info.devs ; mdi ; mdi = mdi->next) {
8d45d196
DW
286 a->container->ss->set_disk(a, mdi->disk.raid_disk,
287 mdi->curr_state);
549e9569
NB
288 if (! (mdi->curr_state & DS_INSYNC))
289 check_degraded = 1;
290 }
291 }
292
293
294 for (mdi = a->info.devs ; mdi ; mdi = mdi->next) {
295 if (mdi->curr_state & DS_FAULTY) {
8d45d196
DW
296 a->container->ss->set_disk(a, mdi->disk.raid_disk,
297 mdi->curr_state);
549e9569
NB
298 check_degraded = 1;
299 mdi->next_state = DS_REMOVE;
300 }
301 }
302
303 if (check_degraded) {
304 // FIXME;
305 }
306
307 a->container->ss->sync_metadata(a);
308
309 /* Effect state changes in the array */
310 if (a->next_state != bad_word)
311 write_attr(array_states[a->next_state], a->info.state_fd);
312 if (a->next_action != bad_action)
313 write_attr(sync_actions[a->next_action], a->action_fd);
314 for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
8d45d196
DW
315 if (mdi->next_state == DS_REMOVE && mdi->state_fd > 0) {
316 int remove_err;
317
318 write_attr("-blocked", mdi->state_fd);
319 /* the kernel may not be able to immediately remove the
320 * disk, we can simply wait until the next event to try
321 * again.
322 */
323 remove_err = write_attr("remove", mdi->state_fd);
324 if (!remove_err) {
325 close(mdi->state_fd);
326 mdi->state_fd = -1;
327 }
328 }
549e9569
NB
329 if (mdi->next_state & DS_INSYNC)
330 write_attr("+in_sync", mdi->state_fd);
331 }
332
333 /* move curr_ to prev_ */
334 a->prev_state = a->curr_state;
335
336 a->prev_action = a->curr_action;
337
338 for (mdi = a->info.devs; mdi ; mdi = mdi->next) {
339 mdi->prev_state = mdi->curr_state;
340 mdi->next_state = 0;
341 }
342
2a0bb19e
DW
343 if (deactivate)
344 a->container = NULL;
345
549e9569
NB
346 return 1;
347}
348
349static int wait_and_act(struct active_array *aa, int pfd, int nowait)
350{
351 fd_set rfds;
352 int maxfd = 0;
353 struct active_array *a;
354 int rv;
355
356 FD_ZERO(&rfds);
357
358 add_fd(&rfds, &maxfd, pfd);
359 for (a = aa ; a ; a = a->next) {
360 struct mdinfo *mdi;
361
2a0bb19e
DW
362 /* once an array has been deactivated only the manager
363 * thread can make us care about it again
364 */
365 if (!a->container)
366 continue;
367
549e9569
NB
368 add_fd(&rfds, &maxfd, a->info.state_fd);
369 add_fd(&rfds, &maxfd, a->action_fd);
370 for (mdi = a->info.devs ; mdi ; mdi = mdi->next)
371 add_fd(&rfds, &maxfd, mdi->state_fd);
372 }
373
374 if (!nowait) {
375 rv = select(maxfd+1, &rfds, NULL, NULL, NULL);
376
377 if (rv <= 0)
378 return rv;
379
380 if (FD_ISSET(pfd, &rfds)) {
381 char buf[4];
382 read(pfd, buf, 4);
383 ; // FIXME read from the pipe
384 }
385 }
386
387 for (a = aa; a ; a = a->next) {
2a0bb19e 388 if (a->replaces && !discard_this) {
549e9569
NB
389 struct active_array **ap;
390 for (ap = &a->next; *ap && *ap != a->replaces;
391 ap = & (*ap)->next)
392 ;
393 if (*ap)
394 *ap = (*ap)->next;
395 discard_this = a->replaces;
396 a->replaces = NULL;
397 }
2a0bb19e
DW
398 if (a->container)
399 rv += read_and_act(a);
549e9569
NB
400 }
401 return rv;
402}
403
404void do_monitor(struct supertype *container)
405{
406 int rv;
407 int first = 1;
408 do {
409 rv = wait_and_act(container->arrays, container->pipe[0], first);
410 first = 0;
411 } while (rv >= 0);
412}