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git.ipfire.org Git - thirdparty/mdadm.git/blob - managemon.c
3 * The management thread for monitoring active md arrays.
4 * This thread does things which might block such as memory
8 * - Find out about new arrays in this container.
9 * Allocate the data structures and open the files.
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.
16 * - Respond to reshape requests by allocating new data structures
17 * and opening new files.
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.
26 * - When a device is added to the container, we add it to the metadata
29 * - Deal with degraded array
30 * We only do this when first noticing the array is degraded.
31 * This can be when we first see the array, when sync completes or
32 * when recovery completes.
34 * Check if number of failed devices suggests recovery is needed, and
36 * Ask metadata to allocate a spare device
37 * Add device as not in_sync and give a role
39 * Open sysfs files and pass to monitor.
40 * Make sure that monitor Starts recovery....
42 * - Pass on metadata updates from external programs such as
43 * mdadm creating a new array.
46 * It might involve adding a new array or changing the status of
47 * a spare, or any reconfig that the kernel doesn't get involved in.
49 * The required updates are received via a named pipe. There will
50 * be one named pipe for each container. Each message contains a
51 * sync marker: 0x5a5aa5a5, A byte count, and the message. This is
52 * passed to the metadata handler which will interpret and process it.
53 * For 'DDF' messages are internal data blocks with the leading
54 * 'magic number' signifying what sort of data it is.
59 * We select on /proc/mdstat and the named pipe.
60 * We create new arrays or updated version of arrays and slip
61 * them into the head of the list, then signal 'monitor' via a pipe write.
62 * 'monitor' will notice and place the old array on a return list.
63 * Metadata updates are placed on a queue just like they arrive
64 * from the named pipe.
66 * When new arrays are found based on correct metadata string, we
67 * need to identify them with an entry in the metadata. Maybe we require
68 * the metadata to be mdX/NN when NN is the index into an appropriate table.
74 * - Watch for spares to be added to the container, and write updated
76 * - Watch for new arrays using this container, confirm they match metadata
77 * and if so, start monitoring them
78 * - Watch for spares being added to monitored arrays. This shouldn't
79 * happen, as we should do all the adding. Just remove them.
80 * - Watch for change in raid-disks, chunk-size, etc. Update metadata and
88 #include <sys/socket.h>
91 static void close_aa(struct active_array
*aa
)
95 for (d
= aa
->info
.devs
; d
; d
= d
->next
)
99 close(aa
->info
.state_fd
);
100 close(aa
->resync_start_fd
);
103 static void free_aa(struct active_array
*aa
)
105 /* Note that this doesn't close fds if they are being used
106 * by a clone. ->container will be set for a clone
108 dprintf("%s: devnum: %d\n", __func__
, aa
->devnum
);
111 while (aa
->info
.devs
) {
112 struct mdinfo
*d
= aa
->info
.devs
;
113 aa
->info
.devs
= d
->next
;
119 static struct active_array
*duplicate_aa(struct active_array
*aa
)
121 struct active_array
*newa
= malloc(sizeof(*newa
));
122 struct mdinfo
**dp1
, **dp2
;
126 newa
->replaces
= NULL
;
127 newa
->info
.next
= NULL
;
129 dp2
= &newa
->info
.devs
;
131 for (dp1
= &aa
->info
.devs
; *dp1
; dp1
= &(*dp1
)->next
) {
133 if ((*dp1
)->state_fd
< 0)
136 d
= malloc(sizeof(*d
));
146 static void write_wakeup(struct supertype
*c
)
148 static struct md_generic_cmd cmd
= { .action
= md_action_ping_monitor
};
153 /* send the monitor thread a pointer to the ping action */
154 write(c
->mgr_pipe
[1], &err
, 1);
157 static void remove_old(void)
160 discard_this
->next
= NULL
;
161 free_aa(discard_this
);
162 if (pending_discard
== discard_this
)
163 pending_discard
= NULL
;
168 static void replace_array(struct supertype
*container
,
169 struct active_array
*old
,
170 struct active_array
*new)
172 /* To replace an array, we add it to the top of the list
173 * marked with ->replaces to point to the original.
174 * 'monitor' will take the original out of the list
175 * and put it on 'discard_this'. We take it from there
179 while (pending_discard
) {
180 write_wakeup(container
);
181 while (discard_this
== NULL
)
185 pending_discard
= old
;
187 new->next
= container
->arrays
;
188 container
->arrays
= new;
189 write_wakeup(container
);
192 struct metadata_update
*update_queue
= NULL
;
193 struct metadata_update
*update_queue_handled
= NULL
;
194 struct metadata_update
*update_queue_pending
= NULL
;
196 void check_update_queue(struct supertype
*container
)
198 while (update_queue_handled
) {
199 struct metadata_update
*this = update_queue_handled
;
200 update_queue_handled
= this->next
;
206 if (update_queue
== NULL
&&
207 update_queue_pending
) {
208 update_queue
= update_queue_pending
;
209 update_queue_pending
= NULL
;
210 write_wakeup(container
);
214 static void queue_metadata_update(struct metadata_update
*mu
)
216 struct metadata_update
**qp
;
218 qp
= &update_queue_pending
;
220 qp
= & ((*qp
)->next
);
224 void wait_update_handled(void)
226 /* Wait for any pending update to be handled by monitor.
227 * i.e. wait until update_queue is NULL
233 static void manage_container(struct mdstat_ent
*mdstat
,
234 struct supertype
*container
)
236 /* The only thing of interest here is if a new device
237 * has been added to the container. We add it to the
238 * array ignoring any metadata on it.
239 * FIXME should we look for compatible metadata and take hints
240 * about spare assignment.... probably not.
242 if (mdstat
->devcnt
!= container
->devcnt
) {
243 /* read /sys/block/NAME/md/dev-??/block/dev to find out
244 * what is there, and compare with container->info.devs
245 * To see what is removed and what is added.
246 * These need to be remove from, or added to, the array
249 container
->devcnt
= mdstat
->devcnt
;
253 static void manage_member(struct mdstat_ent
*mdstat
,
254 struct active_array
*a
)
256 /* Compare mdstat info with known state of member array.
257 * We do not need to look for device state changes here, that
258 * is dealt with by the monitor.
260 * We just look for changes which suggest that a reshape is
262 * Unfortunately decreases in raid_disks don't show up in
263 * mdstat until the reshape completes FIXME.
265 * Actually, we also want to handle degraded arrays here by
266 * trying to find and assign a spare.
267 * We do that whenever the monitor tells us too.
270 a
->info
.array
.raid_disks
= mdstat
->raid_disks
;
271 a
->info
.array
.chunk_size
= mdstat
->chunk_size
;
274 if (a
->check_degraded
) {
275 struct metadata_update
*updates
= NULL
;
276 struct mdinfo
*newdev
;
277 struct active_array
*newa
;
278 wait_update_handled();
279 a
->check_degraded
= 0;
281 /* The array may not be degraded, this is just a good time
284 newdev
= a
->container
->ss
->activate_spare(a
, &updates
);
287 /* Cool, we can add a device or several. */
288 newa
= duplicate_aa(a
);
289 /* suspend recovery - maybe not needed */
291 /* Add device to array and set offset/size/slot.
292 * and open files for each newdev */
293 for (d
= newdev
; d
; d
= d
->next
) {
295 if (sysfs_add_disk(&newa
->info
, d
))
297 newd
= newa
->info
.devs
;
298 newd
->state_fd
= sysfs_open(a
->devnum
,
302 = read_dev_state(newd
->state_fd
);
303 newd
->curr_state
= newd
->prev_state
;
305 queue_metadata_update(updates
);
306 replace_array(a
->container
, a
, newa
);
307 sysfs_set_str(&a
->info
, NULL
, "sync_action", "repair");
312 static void manage_new(struct mdstat_ent
*mdstat
,
313 struct supertype
*container
,
314 struct active_array
*victim
)
316 /* A new array has appeared in this container.
317 * Hopefully it is already recorded in the metadata.
318 * Check, then create the new array to report it to
322 struct active_array
*new;
323 struct mdinfo
*mdi
, *di
;
327 new = malloc(sizeof(*new));
329 memset(new, 0, sizeof(*new));
331 new->devnum
= mdstat
->devnum
;
332 strcpy(new->info
.sys_name
, devnum2devname(new->devnum
));
334 new->prev_state
= new->curr_state
= new->next_state
= inactive
;
335 new->prev_action
= new->curr_action
= new->next_action
= idle
;
337 new->container
= container
;
339 inst
= &mdstat
->metadata_version
[10+strlen(container
->devname
)+1];
341 mdi
= sysfs_read(-1, new->devnum
,
342 GET_LEVEL
|GET_CHUNK
|GET_DISKS
|
343 GET_DEVS
|GET_OFFSET
|GET_SIZE
|GET_STATE
);
345 /* Eeek. Cannot monitor this array.
346 * Mark it to be ignored by setting container to NULL
348 new->container
= NULL
;
349 replace_array(container
, victim
, new);
353 new->info
.array
= mdi
->array
;
355 for (i
= 0; i
< new->info
.array
.raid_disks
; i
++) {
356 struct mdinfo
*newd
= malloc(sizeof(*newd
));
358 for (di
= mdi
->devs
; di
; di
= di
->next
)
359 if (i
== di
->disk
.raid_disk
)
363 memcpy(newd
, di
, sizeof(*newd
));
365 newd
->state_fd
= sysfs_open(new->devnum
,
369 newd
->prev_state
= read_dev_state(newd
->state_fd
);
370 newd
->curr_state
= newd
->prev_state
;
373 newd
->disk
.raid_disk
= i
;
374 newd
->prev_state
= DS_REMOVE
;
375 newd
->curr_state
= DS_REMOVE
;
377 sprintf(newd
->sys_name
, "rd%d", i
);
378 newd
->next
= new->info
.devs
;
379 new->info
.devs
= newd
;
381 new->action_fd
= sysfs_open(new->devnum
, NULL
, "sync_action");
382 new->info
.state_fd
= sysfs_open(new->devnum
, NULL
, "array_state");
383 new->resync_start_fd
= sysfs_open(new->devnum
, NULL
, "resync_start");
384 new->resync_start
= 0;
385 dprintf("%s: inst: %d action: %d state: %d\n", __func__
, atoi(inst
),
386 new->action_fd
, new->info
.state_fd
);
389 // finds and compares.
390 if (container
->ss
->open_new(container
, new, inst
) < 0) {
391 // FIXME close all those files
392 new->container
= NULL
;
393 replace_array(container
, victim
, new);
396 replace_array(container
, victim
, new);
400 void manage(struct mdstat_ent
*mdstat
, struct supertype
*container
)
402 /* We have just read mdstat and need to compare it with
403 * the known active arrays.
404 * Arrays with the wrong metadata are ignored.
407 for ( ; mdstat
; mdstat
= mdstat
->next
) {
408 struct active_array
*a
;
409 if (mdstat
->devnum
== container
->devnum
) {
410 manage_container(mdstat
, container
);
413 if (mdstat
->metadata_version
== NULL
||
414 strncmp(mdstat
->metadata_version
, "external:/", 10) != 0 ||
415 strncmp(mdstat
->metadata_version
+10, container
->devname
,
416 strlen(container
->devname
)) != 0 ||
417 mdstat
->metadata_version
[10+strlen(container
->devname
)]
419 /* Not for this array */
421 /* Looks like a member of this container */
422 for (a
= container
->arrays
; a
; a
= a
->next
) {
423 if (mdstat
->devnum
== a
->devnum
) {
425 manage_member(mdstat
, a
);
429 if (a
== NULL
|| !a
->container
)
430 manage_new(mdstat
, container
, a
);
434 static int handle_message(struct supertype
*container
, struct md_message
*msg
)
436 struct md_generic_cmd
*cmd
= msg
->buf
;
441 switch (cmd
->action
) {
448 void read_sock(struct supertype
*container
)
451 struct md_message msg
;
454 int tmo
= 3; /* 3 second timeout before hanging up the socket */
456 fd
= accept(container
->sock
, NULL
, NULL
);
460 fl
= fcntl(fd
, F_GETFL
, 0);
462 fcntl(fd
, F_SETFL
, fl
);
469 /* read and validate the message */
470 if (receive_message(fd
, &msg
, tmo
) == 0) {
471 err
= handle_message(container
, &msg
);
473 ack(fd
, msg
.seq
, tmo
);
483 } while (!terminate
);
489 void wake_me(int sig
)
495 int manager_ready
= 0;
496 void do_manager(struct supertype
*container
)
498 struct mdstat_ent
*mdstat
;
499 sigset_t block
, orig
;
502 sigaddset(&block
, SIGUSR1
);
504 signal(SIGUSR1
, wake_me
);
512 mdstat
= mdstat_read(1, 0);
514 manage(mdstat
, container
);
516 read_sock(container
);
522 check_update_queue(container
);
525 sigprocmask(SIG_SETMASK
, &block
, &orig
);
527 mdstat_wait_fd(container
->sock
, &orig
);
528 sigprocmask(SIG_SETMASK
, &orig
, NULL
);