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Discard get_sync_pos. We should be using get_resync_start.
[thirdparty/mdadm.git] / managemon.c
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549e9569
NB
1
2/*
3 * The management thread for monitoring active md arrays.
4 * This thread does things which might block such as memory
5 * allocation.
6 * In particular:
7 *
8 * - Find out about new arrays in this container.
9 * Allocate the data structures and open the files.
10 *
11 * For this we watch /proc/mdstat and find new arrays with
12 * metadata type that confirms sharing. e.g. "md4"
13 * When we find a new array we slip it into the list of
14 * arrays and signal 'monitor' by writing to a pipe.
15 *
16 * - Respond to reshape requests by allocating new data structures
17 * and opening new files.
18 *
19 * These come as a change to raid_disks. We allocate a new
20 * version of the data structures and slip it into the list.
21 * 'monitor' will notice and release the old version.
22 * Changes to level, chunksize, layout.. do not need re-allocation.
23 * Reductions in raid_disks don't really either, but we handle
24 * them the same way for consistency.
25 *
26 * - When a device is added to the container, we add it to the metadata
27 * as a spare.
28 *
29 * - assist with activating spares by opening relevant sysfs file.
30 *
31 * - Pass on metadata updates from external programs such as
32 * mdadm creating a new array.
33 *
34 * This is most-messy.
35 * It might involve adding a new array or changing the status of
36 * a spare, or any reconfig that the kernel doesn't get involved in.
37 *
38 * The required updates are received via a named pipe. There will
39 * be one named pipe for each container. Each message contains a
40 * sync marker: 0x5a5aa5a5, A byte count, and the message. This is
41 * passed to the metadata handler which will interpret and process it.
42 * For 'DDF' messages are internal data blocks with the leading
43 * 'magic number' signifying what sort of data it is.
44 *
45 */
46
47/*
48 * We select on /proc/mdstat and the named pipe.
49 * We create new arrays or updated version of arrays and slip
50 * them into the head of the list, then signal 'monitor' via a pipe write.
51 * 'monitor' will notice and place the old array on a return list.
52 * Metadata updates are placed on a queue just like they arrive
53 * from the named pipe.
54 *
55 * When new arrays are found based on correct metadata string, we
56 * need to identify them with an entry in the metadata. Maybe we require
57 * the metadata to be mdX/NN when NN is the index into an appropriate table.
58 *
59 */
60
61/*
62 * List of tasks:
63 * - Watch for spares to be added to the container, and write updated
64 * metadata to them.
65 * - Watch for new arrays using this container, confirm they match metadata
66 * and if so, start monitoring them
67 * - Watch for spares being added to monitored arrays. This shouldn't
68 * happen, as we should do all the adding. Just remove them.
69 * - Watch for change in raid-disks, chunk-size, etc. Update metadata and
70 * start a reshape.
71 */
72#ifndef _GNU_SOURCE
73#define _GNU_SOURCE
74#endif
75#include "mdadm.h"
76#include "mdmon.h"
77#include <sys/socket.h>
1ed3f387 78#include <signal.h>
549e9569 79
2a0bb19e
DW
80static void close_aa(struct active_array *aa)
81{
82 struct mdinfo *d;
83
84 for (d = aa->info.devs; d; d = d->next)
85 close(d->state_fd);
86
87 close(aa->action_fd);
88 close(aa->info.state_fd);
89 close(aa->resync_start_fd);
2a0bb19e
DW
90}
91
549e9569
NB
92static void free_aa(struct active_array *aa)
93{
2a0bb19e
DW
94 /* Note that this doesn't close fds if they are being used
95 * by a clone. ->container will be set for a clone
549e9569 96 */
2a0bb19e
DW
97 if (!aa->container)
98 close_aa(aa);
549e9569
NB
99 while (aa->info.devs) {
100 struct mdinfo *d = aa->info.devs;
101 aa->info.devs = d->next;
102 free(d);
103 }
104 free(aa);
105}
106
2a0bb19e
DW
107static void write_wakeup(struct supertype *c)
108{
3e70c845
DW
109 static struct md_generic_cmd cmd = { .action = md_action_ping_monitor };
110 int err;
111
112 active_cmd = &cmd;
113
114 /* send the monitor thread a pointer to the ping action */
115 write(c->mgr_pipe[1], &err, 1);
116 read(c->mon_pipe[0], &err, 1);
2a0bb19e
DW
117}
118
1ed3f387
NB
119static void remove_old(void)
120{
121 if (discard_this) {
122 discard_this->next = NULL;
123 free_aa(discard_this);
124 if (pending_discard == discard_this)
125 pending_discard = NULL;
126 discard_this = NULL;
127 }
128}
129
549e9569
NB
130static void replace_array(struct supertype *container,
131 struct active_array *old,
132 struct active_array *new)
133{
134 /* To replace an array, we add it to the top of the list
135 * marked with ->replaces to point to the original.
136 * 'monitor' will take the original out of the list
137 * and put it on 'discard_this'. We take it from there
138 * and discard it.
139 */
1ed3f387 140 remove_old();
549e9569 141 while (pending_discard) {
1ed3f387 142 write_wakeup(container);
549e9569
NB
143 while (discard_this == NULL)
144 sleep(1);
1ed3f387 145 remove_old();
549e9569
NB
146 }
147 pending_discard = old;
148 new->replaces = old;
149 new->next = container->arrays;
150 container->arrays = new;
2a0bb19e 151 write_wakeup(container);
549e9569
NB
152}
153
549e9569
NB
154static void manage_container(struct mdstat_ent *mdstat,
155 struct supertype *container)
156{
157 /* The only thing of interest here is if a new device
158 * has been added to the container. We add it to the
159 * array ignoring any metadata on it.
160 * FIXME should we look for compatible metadata and take hints
161 * about spare assignment.... probably not.
162 *
163 */
164 if (mdstat->devcnt != container->devcnt) {
165 /* read /sys/block/NAME/md/dev-??/block/dev to find out
166 * what is there, and compare with container->info.devs
167 * To see what is removed and what is added.
168 * These need to be remove from, or added to, the array
169 */
170 // FIXME
171 container->devcnt = mdstat->devcnt;
172 }
173}
174
175static void manage_member(struct mdstat_ent *mdstat,
176 struct active_array *a)
177{
178 /* Compare mdstat info with known state of member array.
179 * We do not need to look for device state changes here, that
180 * is dealt with by the monitor.
181 *
182 * We just look for changes which suggest that a reshape is
183 * being requested.
184 * Unfortunately decreases in raid_disks don't show up in
185 * mdstat until the reshape completes FIXME.
186 */
187 // FIXME
188 a->info.array.raid_disks = mdstat->raid_disks;
189 a->info.array.chunk_size = mdstat->chunk_size;
190 // MORE
191
192}
193
549e9569 194static void manage_new(struct mdstat_ent *mdstat,
2a0bb19e
DW
195 struct supertype *container,
196 struct active_array *victim)
549e9569
NB
197{
198 /* A new array has appeared in this container.
199 * Hopefully it is already recorded in the metadata.
200 * Check, then create the new array to report it to
201 * the monitor.
202 */
203
204 struct active_array *new;
205 struct mdinfo *mdi, *di;
206 char *n;
207 int inst;
208 int i;
209
210 new = malloc(sizeof(*new));
211
d52690ac
NB
212 memset(new, 0, sizeof(*new));
213
549e9569
NB
214 new->devnum = mdstat->devnum;
215
216 new->prev_state = new->curr_state = new->next_state = inactive;
217 new->prev_action= new->curr_action= new->next_action= idle;
218
219 new->container = container;
220
221 n = &mdstat->metadata_version[10+strlen(container->devname)+1];
222 inst = atoi(n);
223 if (inst < 0)
224 abort();//FIXME
225
226 mdi = sysfs_read(-1, new->devnum,
227 GET_LEVEL|GET_CHUNK|GET_DISKS|
228 GET_DEVS|GET_OFFSET|GET_SIZE|GET_STATE);
229 if (!mdi) {
230 /* Eeek. Cannot monitor this array.
231 * Mark it to be ignored by setting container to NULL
232 */
233 new->container = NULL;
2a0bb19e 234 replace_array(container, victim, new);
549e9569
NB
235 return;
236 }
237
238 new->info.array = mdi->array;
239
240 for (i = 0; i < new->info.array.raid_disks; i++) {
241 struct mdinfo *newd = malloc(sizeof(*newd));
242
243 for (di = mdi->devs; di; di = di->next)
244 if (i == di->disk.raid_disk)
245 break;
246
247 if (di) {
248 memcpy(newd, di, sizeof(*newd));
249
250 sprintf(newd->sys_name, "rd%d", i);
251
252 newd->state_fd = sysfs_open(new->devnum,
253 newd->sys_name,
254 "state");
255
256 newd->prev_state = read_dev_state(newd->state_fd);
257 newd->curr_state = newd->curr_state;
258 } else {
259 newd->state_fd = -1;
260 }
261 newd->next = new->info.devs;
262 new->info.devs = newd;
263 }
264 new->action_fd = sysfs_open(new->devnum, NULL, "sync_action");
265 new->info.state_fd = sysfs_open(new->devnum, NULL, "array_state");
c052ba30 266 new->resync_start_fd = sysfs_open(new->devnum, NULL, "resync_start");
77402e51 267 new->resync_start = 0;
549e9569 268
4fa5aef9 269 sysfs_free(mdi);
549e9569
NB
270 // finds and compares.
271 if (container->ss->open_new(container, new, inst) < 0) {
272 // FIXME close all those files
273 new->container = NULL;
2a0bb19e 274 replace_array(container, victim, new);
549e9569
NB
275 return;
276 }
2a0bb19e 277 replace_array(container, victim, new);
549e9569
NB
278 return;
279}
280
5d19760d 281void manage(struct mdstat_ent *mdstat, struct supertype *container)
549e9569
NB
282{
283 /* We have just read mdstat and need to compare it with
284 * the known active arrays.
285 * Arrays with the wrong metadata are ignored.
286 */
287
288 for ( ; mdstat ; mdstat = mdstat->next) {
289 struct active_array *a;
290 if (mdstat->devnum == container->devnum) {
291 manage_container(mdstat, container);
292 continue;
293 }
294 if (mdstat->metadata_version == NULL ||
295 strncmp(mdstat->metadata_version, "external:/", 10) != 0 ||
296 strncmp(mdstat->metadata_version+10, container->devname,
297 strlen(container->devname)) != 0 ||
298 mdstat->metadata_version[10+strlen(container->devname)]
299 != '/')
300 /* Not for this array */
301 continue;
302 /* Looks like a member of this container */
5d19760d 303 for (a = container->arrays; a; a = a->next) {
549e9569
NB
304 if (mdstat->devnum == a->devnum) {
305 if (a->container)
306 manage_member(mdstat, a);
307 break;
308 }
309 }
2a0bb19e
DW
310 if (a == NULL || !a->container)
311 manage_new(mdstat, container, a);
549e9569
NB
312 }
313}
314
3e70c845
DW
315static int handle_message(struct supertype *container, struct md_message *msg)
316{
317 int err;
318 struct md_generic_cmd *cmd = msg->buf;
319
320 if (!cmd)
321 return 0;
322
323 switch (cmd->action) {
324 case md_action_remove_device:
325
326 /* forward to the monitor */
327 active_cmd = cmd;
328 write(container->mgr_pipe[1], &err, 1);
329 read(container->mon_pipe[0], &err, 1);
330 return err;
331
332 default:
333 return -1;
334 }
335}
336
337void read_sock(struct supertype *container)
549e9569
NB
338{
339 int fd;
b109d928
DW
340 struct md_message msg;
341 int terminate = 0;
342 long fl;
343 int tmo = 3; /* 3 second timeout before hanging up the socket */
549e9569 344
3e70c845 345 fd = accept(container->sock, NULL, NULL);
549e9569
NB
346 if (fd < 0)
347 return;
b109d928
DW
348
349 fl = fcntl(fd, F_GETFL, 0);
350 fl |= O_NONBLOCK;
351 fcntl(fd, F_SETFL, fl);
352
353 do {
3e70c845
DW
354 int err;
355
b109d928
DW
356 msg.buf = NULL;
357
358 /* read and validate the message */
359 if (receive_message(fd, &msg, tmo) == 0) {
3e70c845
DW
360 err = handle_message(container, &msg);
361 if (!err)
362 ack(fd, msg.seq, tmo);
363 else
364 nack(fd, err, tmo);
b109d928
DW
365 } else {
366 terminate = 1;
367 nack(fd, -1, tmo);
368 }
369
370 if (msg.buf)
371 free(msg.buf);
372 } while (!terminate);
373
549e9569
NB
374 close(fd);
375}
1ed3f387
NB
376
377static int woke = 0;
378void wake_me(int sig)
379{
380 woke = 1;
381}
382
e0d6609f
NB
383int exit_now = 0;
384int manager_ready = 0;
549e9569
NB
385void do_manager(struct supertype *container)
386{
387 struct mdstat_ent *mdstat;
1ed3f387
NB
388 sigset_t block, orig;
389
390 sigemptyset(&block);
391 sigaddset(&block, SIGUSR1);
392
393 signal(SIGUSR1, wake_me);
549e9569
NB
394
395 do {
1ed3f387
NB
396 woke = 0;
397
e0d6609f
NB
398 if (exit_now)
399 exit(0);
400
549e9569
NB
401 mdstat = mdstat_read(1, 0);
402
5d19760d 403 manage(mdstat, container);
549e9569 404
3e70c845 405 read_sock(container);
549e9569 406
4fa5aef9
DW
407 free_mdstat(mdstat);
408
1ed3f387
NB
409 remove_old();
410
e0d6609f 411 manager_ready = 1;
1ed3f387
NB
412 sigprocmask(SIG_SETMASK, &block, &orig);
413 if (woke == 0)
414 mdstat_wait_fd(container->sock, &orig);
415 sigprocmask(SIG_SETMASK, &orig, NULL);
549e9569
NB
416 } while(1);
417}