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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 * - assist with activating spares by opening relevant sysfs file.
31 * - Pass on metadata updates from external programs such as
32 * mdadm creating a new array.
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.
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.
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.
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.
63 * - Watch for spares to be added to the container, and write updated
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
77 #include <sys/socket.h>
80 static void close_aa(struct active_array
*aa
)
84 for (d
= aa
->info
.devs
; d
; d
= d
->next
)
88 close(aa
->info
.state_fd
);
89 close(aa
->resync_start_fd
);
92 static void free_aa(struct active_array
*aa
)
94 /* Note that this doesn't close fds if they are being used
95 * by a clone. ->container will be set for a clone
99 while (aa
->info
.devs
) {
100 struct mdinfo
*d
= aa
->info
.devs
;
101 aa
->info
.devs
= d
->next
;
107 static void write_wakeup(struct supertype
*c
)
109 static struct md_generic_cmd cmd
= { .action
= md_action_ping_monitor
};
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);
119 static void remove_old(void)
122 discard_this
->next
= NULL
;
123 free_aa(discard_this
);
124 if (pending_discard
== discard_this
)
125 pending_discard
= NULL
;
130 static void replace_array(struct supertype
*container
,
131 struct active_array
*old
,
132 struct active_array
*new)
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
141 while (pending_discard
) {
142 write_wakeup(container
);
143 while (discard_this
== NULL
)
147 pending_discard
= old
;
149 new->next
= container
->arrays
;
150 container
->arrays
= new;
151 write_wakeup(container
);
154 static void manage_container(struct mdstat_ent
*mdstat
,
155 struct supertype
*container
)
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.
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
171 container
->devcnt
= mdstat
->devcnt
;
175 static void manage_member(struct mdstat_ent
*mdstat
,
176 struct active_array
*a
)
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.
182 * We just look for changes which suggest that a reshape is
184 * Unfortunately decreases in raid_disks don't show up in
185 * mdstat until the reshape completes FIXME.
188 a
->info
.array
.raid_disks
= mdstat
->raid_disks
;
189 a
->info
.array
.chunk_size
= mdstat
->chunk_size
;
194 static void manage_new(struct mdstat_ent
*mdstat
,
195 struct supertype
*container
,
196 struct active_array
*victim
)
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
204 struct active_array
*new;
205 struct mdinfo
*mdi
, *di
;
210 new = malloc(sizeof(*new));
212 memset(new, 0, sizeof(*new));
214 new->devnum
= mdstat
->devnum
;
216 new->prev_state
= new->curr_state
= new->next_state
= inactive
;
217 new->prev_action
= new->curr_action
= new->next_action
= idle
;
219 new->container
= container
;
221 n
= &mdstat
->metadata_version
[10+strlen(container
->devname
)+1];
226 mdi
= sysfs_read(-1, new->devnum
,
227 GET_LEVEL
|GET_CHUNK
|GET_DISKS
|
228 GET_DEVS
|GET_OFFSET
|GET_SIZE
|GET_STATE
);
230 /* Eeek. Cannot monitor this array.
231 * Mark it to be ignored by setting container to NULL
233 new->container
= NULL
;
234 replace_array(container
, victim
, new);
238 new->info
.array
= mdi
->array
;
240 for (i
= 0; i
< new->info
.array
.raid_disks
; i
++) {
241 struct mdinfo
*newd
= malloc(sizeof(*newd
));
243 for (di
= mdi
->devs
; di
; di
= di
->next
)
244 if (i
== di
->disk
.raid_disk
)
248 memcpy(newd
, di
, sizeof(*newd
));
250 sprintf(newd
->sys_name
, "rd%d", i
);
252 newd
->state_fd
= sysfs_open(new->devnum
,
256 newd
->prev_state
= read_dev_state(newd
->state_fd
);
257 newd
->curr_state
= newd
->curr_state
;
261 newd
->next
= new->info
.devs
;
262 new->info
.devs
= newd
;
264 new->action_fd
= sysfs_open(new->devnum
, NULL
, "sync_action");
265 new->info
.state_fd
= sysfs_open(new->devnum
, NULL
, "array_state");
266 new->resync_start_fd
= sysfs_open(new->devnum
, NULL
, "resync_start");
267 new->resync_start
= 0;
270 // finds and compares.
271 if (container
->ss
->open_new(container
, new, inst
) < 0) {
272 // FIXME close all those files
273 new->container
= NULL
;
274 replace_array(container
, victim
, new);
277 replace_array(container
, victim
, new);
281 void manage(struct mdstat_ent
*mdstat
, struct supertype
*container
)
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.
288 for ( ; mdstat
; mdstat
= mdstat
->next
) {
289 struct active_array
*a
;
290 if (mdstat
->devnum
== container
->devnum
) {
291 manage_container(mdstat
, container
);
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
)]
300 /* Not for this array */
302 /* Looks like a member of this container */
303 for (a
= container
->arrays
; a
; a
= a
->next
) {
304 if (mdstat
->devnum
== a
->devnum
) {
306 manage_member(mdstat
, a
);
310 if (a
== NULL
|| !a
->container
)
311 manage_new(mdstat
, container
, a
);
315 static int handle_message(struct supertype
*container
, struct md_message
*msg
)
318 struct md_generic_cmd
*cmd
= msg
->buf
;
323 switch (cmd
->action
) {
324 case md_action_remove_device
:
326 /* forward to the monitor */
328 write(container
->mgr_pipe
[1], &err
, 1);
329 read(container
->mon_pipe
[0], &err
, 1);
337 void read_sock(struct supertype
*container
)
340 struct md_message msg
;
343 int tmo
= 3; /* 3 second timeout before hanging up the socket */
345 fd
= accept(container
->sock
, NULL
, NULL
);
349 fl
= fcntl(fd
, F_GETFL
, 0);
351 fcntl(fd
, F_SETFL
, fl
);
358 /* read and validate the message */
359 if (receive_message(fd
, &msg
, tmo
) == 0) {
360 err
= handle_message(container
, &msg
);
362 ack(fd
, msg
.seq
, tmo
);
372 } while (!terminate
);
378 void wake_me(int sig
)
384 int manager_ready
= 0;
385 void do_manager(struct supertype
*container
)
387 struct mdstat_ent
*mdstat
;
388 sigset_t block
, orig
;
391 sigaddset(&block
, SIGUSR1
);
393 signal(SIGUSR1
, wake_me
);
401 mdstat
= mdstat_read(1, 0);
403 manage(mdstat
, container
);
405 read_sock(container
);
412 sigprocmask(SIG_SETMASK
, &block
, &orig
);
414 mdstat_wait_fd(container
->sock
, &orig
);
415 sigprocmask(SIG_SETMASK
, &orig
, NULL
);