2 * Copyright (C) 2008 Intel Corporation
4 * mdmon socket / message handling
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
28 #include <sys/types.h>
29 #include <sys/socket.h>
34 static const __u32 start_magic = 0x5a5aa5a5;
35 static const __u32 end_magic = 0xa5a55a5a;
37 static int send_buf(int fd, const void* buf, int len, int tmo)
41 struct timeval timeout = {tmo, 0};
42 struct timeval *ptmo = tmo ? &timeout : NULL;
47 rv = select(fd+1, NULL, &set, NULL, ptmo);
50 rv = write(fd, buf, len);
59 static int recv_buf(int fd, void* buf, int len, int tmo)
63 struct timeval timeout = {tmo, 0};
64 struct timeval *ptmo = tmo ? &timeout : NULL;
69 rv = select(fd+1, &set, NULL, NULL, ptmo);
72 rv = read(fd, buf, len);
82 int send_message(int fd, struct metadata_update *msg, int tmo)
87 rv = send_buf(fd, &start_magic, 4, tmo);
88 rv = rv ?: send_buf(fd, &len, 4, tmo);
90 rv = rv ?: send_buf(fd, msg->buf, msg->len, tmo);
91 rv = send_buf(fd, &end_magic, 4, tmo);
96 int receive_message(int fd, struct metadata_update *msg, int tmo)
102 rv = recv_buf(fd, &magic, 4, tmo);
103 if (rv < 0 || magic != start_magic)
105 rv = recv_buf(fd, &len, 4, tmo);
106 if (rv < 0 || len > MSG_MAX_LEN)
109 msg->buf = malloc(len);
110 if (msg->buf == NULL)
112 rv = recv_buf(fd, msg->buf, len, tmo);
119 rv = recv_buf(fd, &magic, 4, tmo);
120 if (rv < 0 || magic != end_magic) {
128 int ack(int fd, int tmo)
130 struct metadata_update msg = { .len = 0 };
132 return send_message(fd, &msg, tmo);
135 int wait_reply(int fd, int tmo)
137 struct metadata_update msg;
138 int err = receive_message(fd, &msg, tmo);
140 /* mdmon sent extra data, but caller only cares that we got a
143 if (err == 0 && msg.len > 0)
149 int connect_monitor(char *devname)
154 struct sockaddr_un addr;
158 pos = sprintf(path, "%s/", MDMON_DIR);
159 if (is_subarray(devname)) {
161 c = strchr(devname, '/');
164 snprintf(&path[pos], c - devname + 1, "%s", devname);
167 pos += sprintf(&path[pos], "%s", devname);
168 sprintf(&path[pos], ".sock");
170 sfd = socket(PF_LOCAL, SOCK_STREAM, 0);
174 addr.sun_family = PF_LOCAL;
175 strcpy(addr.sun_path, path);
176 if (connect(sfd, &addr, sizeof(addr)) < 0) {
181 fl = fcntl(sfd, F_GETFL, 0);
183 fcntl(sfd, F_SETFL, fl);
188 int fping_monitor(int sfd)
195 /* try to ping existing socket */
196 if (ack(sfd, 20) != 0)
199 /* check the reply */
200 if (!err && wait_reply(sfd, 20) != 0)
206 /* give the monitor a chance to update the metadata */
207 int ping_monitor(char *devname)
209 int sfd = connect_monitor(devname);
210 int err = fping_monitor(sfd);
216 /* ping monitor using device number */
217 int ping_monitor_by_id(int devnum)
220 char *container = devnum2devname(devnum);
223 err = ping_monitor(container);
230 static char *ping_monitor_version(char *devname)
232 int sfd = connect_monitor(devname);
233 struct metadata_update msg;
239 if (ack(sfd, 20) != 0)
242 if (!err && receive_message(sfd, &msg, 20) != 0)
247 if (err || !msg.len || !msg.buf)
252 int unblock_subarray(struct mdinfo *sra, const int unfreeze)
258 sprintf(buf, "external:%s\n", sra->text_version);
264 sysfs_set_str(sra, NULL, "metadata_version", buf) ||
266 sysfs_attribute_available(sra, NULL, "sync_action") &&
267 sysfs_set_str(sra, NULL, "sync_action", "idle")))
272 int block_subarray(struct mdinfo *sra)
277 sprintf(buf, "external:%s\n", sra->text_version);
279 if (sysfs_set_str(sra, NULL, "metadata_version", buf))
285 * block_monitor - prevent mdmon spare assignment
286 * @container - container to block
287 * @freeze - flag to additionally freeze sync_action
289 * This is used by the reshape code to freeze the container, and the
290 * auto-rebuild implementation to atomically move spares.
291 * In both cases we need to stop mdmon from assigning spares to replace
292 * failed devices as we might have other plans for the spare.
293 * For the reshape case we also need to 'freeze' sync_action so that
294 * no recovery happens until we have fully prepared for the reshape.
296 * We tell mdmon that the array is frozen by marking the 'metadata' name
297 * with a leading '-'. The previously told mdmon "Don't make this array
298 * read/write, leave it readonly". Now it means a more general "Don't
299 * reconfigure this array at all".
300 * As older versions of mdmon (which might run from initrd) don't understand
301 * this, we first check that the running mdmon is new enough.
303 int block_monitor(char *container, const int freeze)
305 int devnum = devname2devnum(container);
306 struct mdstat_ent *ent, *e, *e2;
307 struct mdinfo *sra = NULL;
308 char *version = NULL;
312 if (!mdmon_running(devnum)) {
313 /* if mdmon is not active we assume that any instance that is
314 * later started will match the current mdadm version, if this
315 * assumption is violated we may inadvertantly rebuild an array
316 * that was meant for reshape, or start rebuild on a spare that
317 * was to be moved to another container
323 version = ping_monitor_version(container);
324 ver = version ? mdadm_version(version) : -1;
328 ": mdmon instance for %s cannot be disabled\n",
334 ent = mdstat_read(0, 0);
337 ": failed to read /proc/mdstat while disabling mdmon\n");
341 /* freeze container contents */
342 for (e = ent; e; e = e->next) {
343 if (!is_container_member(e, container))
346 sra = sysfs_read(-1, e->devnum, GET_VERSION);
349 ": failed to read sysfs for subarray%s\n",
350 to_subarray(e, container));
353 /* can't reshape an array that we can't monitor */
354 if (sra->text_version[0] == '-')
357 if (freeze && sysfs_freeze_array(sra) < 1)
359 /* flag this array to not be modified by mdmon (close race with
360 * takeover in reshape case and spare reassignment in the
363 if (block_subarray(sra))
365 ping_monitor(container);
367 /* check that we did not race with recovery */
369 !sysfs_attribute_available(sra, NULL, "sync_action")) ||
371 sysfs_attribute_available(sra, NULL, "sync_action") &&
372 sysfs_get_str(sra, NULL, "sync_action", buf, 20) > 0 &&
373 strcmp(buf, "frozen\n") == 0))
376 unblock_subarray(sra, 0);
379 /* Double check against races - there should be no spares
383 sra = sysfs_read(-1, e->devnum, GET_DEVS | GET_STATE);
384 if (sra && sra->array.spare_disks > 0) {
385 unblock_subarray(sra, freeze);
391 fprintf(stderr, Name ": failed to freeze subarray%s\n",
392 to_subarray(e, container));
394 /* thaw the partially frozen container */
395 for (e2 = ent; e2 && e2 != e; e2 = e2->next) {
396 if (!is_container_member(e2, container))
399 sra = sysfs_read(-1, e2->devnum, GET_VERSION);
400 if (unblock_subarray(sra, freeze))
401 fprintf(stderr, Name ": Failed to unfreeze %s\n", e2->dev);
404 ping_monitor(container); /* cleared frozen */
414 void unblock_monitor(char *container, const int unfreeze)
416 struct mdstat_ent *ent, *e;
417 struct mdinfo *sra = NULL;
420 ent = mdstat_read(0, 0);
423 ": failed to read /proc/mdstat while unblocking container\n");
427 /* unfreeze container contents */
428 for (e = ent; e; e = e->next) {
429 if (!is_container_member(e, container))
432 sra = sysfs_read(-1, e->devnum, GET_VERSION|GET_LEVEL);
433 if (sra->array.level > 0)
435 if (unblock_subarray(sra, unfreeze))
436 fprintf(stderr, Name ": Failed to unfreeze %s\n", e->dev);
439 ping_monitor(container);
447 /* give the manager a chance to view the updated container state. This
448 * would naturally happen due to the manager noticing a change in
449 * /proc/mdstat; however, pinging encourages this detection to happen
450 * while an exclusive open() on the container is active
452 int ping_manager(char *devname)
454 int sfd = connect_monitor(devname);
455 struct metadata_update msg = { .len = -1 };
461 err = send_message(sfd, &msg, 20);
463 /* check the reply */
464 if (!err && wait_reply(sfd, 20) != 0)