[thirdparty/mdadm.git] / msg.c

/*
 * Copyright (C) 2008 Intel Corporation
 *
 * 	mdmon socket / message handling
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 */
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include "mdadm.h"
#include "mdmon.h"

static const __u32 start_magic = 0x5a5aa5a5;
static const __u32 end_magic = 0xa5a55a5a;

static int send_buf(int fd, const void* buf, int len, int tmo)
{
	fd_set set;
	int rv;
	struct timeval timeout = {tmo, 0};
	struct timeval *ptmo = tmo ? &timeout : NULL;

	while (len) {
		FD_ZERO(&set);
		FD_SET(fd, &set);
		rv = select(fd+1, NULL, &set, NULL, ptmo);
		if (rv <= 0)
			return -1;
		rv = write(fd, buf, len);
		if (rv <= 0)
			return -1;
		len -= rv;
		buf += rv;
	}
	return 0;
}

static int recv_buf(int fd, void* buf, int len, int tmo)
{
	fd_set set;
	int rv;
	struct timeval timeout = {tmo, 0};
	struct timeval *ptmo = tmo ? &timeout : NULL;

	while (len) {
		FD_ZERO(&set);
		FD_SET(fd, &set);
		rv = select(fd+1, &set, NULL, NULL, ptmo);
		if (rv <= 0)
			return -1;
		rv = read(fd, buf, len);
		if (rv <= 0)
			return -1;
		len -= rv;
		buf += rv;
	}
	return 0;
}


int send_message(int fd, struct metadata_update *msg, int tmo)
{
	__s32 len = msg->len;
	int rv;

	rv = send_buf(fd, &start_magic, 4, tmo);
	rv = rv ?: send_buf(fd, &len, 4, tmo);
	if (len > 0)
		rv = rv ?: send_buf(fd, msg->buf, msg->len, tmo);
	rv = send_buf(fd, &end_magic, 4, tmo);

	return rv;
}

int receive_message(int fd, struct metadata_update *msg, int tmo)
{
	__u32 magic;
	__s32 len;
	int rv;

	rv = recv_buf(fd, &magic, 4, tmo);
	if (rv < 0 || magic != start_magic)
		return -1;
	rv = recv_buf(fd, &len, 4, tmo);
	if (rv < 0 || len > MSG_MAX_LEN)
		return -1;
	if (len > 0) {
		msg->buf = xmalloc(len);
		rv = recv_buf(fd, msg->buf, len, tmo);
		if (rv < 0) {
			free(msg->buf);
			return -1;
		}
	} else
		msg->buf = NULL;
	rv = recv_buf(fd, &magic, 4, tmo);
	if (rv < 0 || magic != end_magic) {
		free(msg->buf);
		return -1;
	}
	msg->len = len;
	return 0;
}

int ack(int fd, int tmo)
{
	struct metadata_update msg = { .len = 0 };

	return send_message(fd, &msg, tmo);
}

int wait_reply(int fd, int tmo)
{
	struct metadata_update msg;
	int err = receive_message(fd, &msg, tmo);

	/* mdmon sent extra data, but caller only cares that we got a
	 * successful reply
	 */
	if (err == 0 && msg.len > 0)
		free(msg.buf);

	return err;
}

int connect_monitor(char *devname)
{
	char path[100];
	int sfd;
	long fl;
	struct sockaddr_un addr;
	int pos;
	char *c;

	pos = sprintf(path, "%s/", MDMON_DIR);
	if (is_subarray(devname)) {
		devname++;
		c = strchr(devname, '/');
		if (!c)
			return -1;
		snprintf(&path[pos], c - devname + 1, "%s", devname);
		pos += c - devname;
	} else
		pos += sprintf(&path[pos], "%s", devname);
	sprintf(&path[pos], ".sock");

	sfd = socket(PF_LOCAL, SOCK_STREAM, 0);
	if (sfd < 0)
		return -1;

	addr.sun_family = PF_LOCAL;
	strcpy(addr.sun_path, path);
	if (connect(sfd, &addr, sizeof(addr)) < 0) {
		close(sfd);
		return -1;
	}

	fl = fcntl(sfd, F_GETFL, 0);
	fl |= O_NONBLOCK;
	fcntl(sfd, F_SETFL, fl);

	return sfd;
}

int fping_monitor(int sfd)
{
	int err = 0;

	if (sfd < 0)
		return sfd;

	/* try to ping existing socket */
	if (ack(sfd, 20) != 0)
		err = -1;

	/* check the reply */
	if (!err && wait_reply(sfd, 20) != 0)
		err = -1;

	return err;
}

/* give the monitor a chance to update the metadata */
int ping_monitor(char *devname)
{
	int sfd = connect_monitor(devname);
	int err;

	if (sfd >= 0) {
		err = fping_monitor(sfd);
		close(sfd);
	} else
		err = -1;

	return err;
}

/* ping monitor using device number */
int ping_monitor_by_id(int devnum)
{
	int err = -1;
	char *container = devnum2devname(devnum);

	if (container) {
		err = ping_monitor(container);
		free(container);
	}

	return err;
}

static char *ping_monitor_version(char *devname)
{
	int sfd = connect_monitor(devname);
	struct metadata_update msg;
	int err = 0;

	if (sfd < 0)
		return NULL;

	if (ack(sfd, 20) != 0)
		err = -1;

	if (!err && receive_message(sfd, &msg, 20) != 0)
		err = -1;

	close(sfd);

	if (err || !msg.len || !msg.buf)
		return NULL;
	return msg.buf;
}

int unblock_subarray(struct mdinfo *sra, const int unfreeze)
{
	char buf[64];
	int rc = 0;

	if (sra) {
		sprintf(buf, "external:%s\n", sra->text_version);
		buf[9] = '/';
	} else
		buf[9] = '-';

	if (buf[9] == '-' ||
	    sysfs_set_str(sra, NULL, "metadata_version", buf) ||
	    (unfreeze &&
	     sysfs_attribute_available(sra, NULL, "sync_action") &&
	     sysfs_set_str(sra, NULL, "sync_action", "idle")))
		rc = -1;
	return rc;
}

int block_subarray(struct mdinfo *sra)
{
	char buf[64];
	int rc = 0;

	sprintf(buf, "external:%s\n", sra->text_version);
	buf[9] = '-';
	if (sysfs_set_str(sra, NULL, "metadata_version", buf))
		rc = -1;

	return rc;
}

/* check mdmon version if it supports
 * array blocking mechanism
 */
int check_mdmon_version(char *container)
{
	char *version = NULL;
	int devnum = devname2devnum(container);

	if (!mdmon_running(devnum)) {
		/* if mdmon is not active we assume that any instance that is
		 * later started will match the current mdadm version, if this
		 * assumption is violated we may inadvertantly rebuild an array
		 * that was meant for reshape, or start rebuild on a spare that
		 * was to be moved to another container
		 */
		/* pass */;
	} else {
		int ver;

		version = ping_monitor_version(container);
		ver = version ? mdadm_version(version) : -1;
		free(version);
		if (ver < 3002000) {
			pr_err("mdmon instance for %s cannot be disabled\n",
			       container);
			return -1;
		}
	}

	return 0;
}

/**
 * block_monitor - prevent mdmon spare assignment
 * @container - container to block
 * @freeze - flag to additionally freeze sync_action
 *
 * This is used by the reshape code to freeze the container, and the
 * auto-rebuild implementation to atomically move spares.
 * In both cases we need to stop mdmon from assigning spares to replace
 * failed devices as we might have other plans for the spare.
 * For the reshape case we also need to 'freeze' sync_action so that
 * no recovery happens until we have fully prepared for the reshape.
 *
 * We tell mdmon that the array is frozen by marking the 'metadata' name
 * with a leading '-'.  The previously told mdmon "Don't make this array
 * read/write, leave it readonly".  Now it means a more general "Don't
 * reconfigure this array at all".
 * As older versions of mdmon (which might run from initrd) don't understand
 * this, we first check that the running mdmon is new enough.
 */
int block_monitor(char *container, const int freeze)
{
	struct mdstat_ent *ent, *e, *e2;
	struct mdinfo *sra = NULL;
	char buf[64];
	int rv = 0;

	if (check_mdmon_version(container))
		return -1;

	ent = mdstat_read(0, 0);
	if (!ent) {
		pr_err("failed to read /proc/mdstat while disabling mdmon\n");
		return -1;
	}

	/* freeze container contents */
	for (e = ent; e; e = e->next) {
		if (!is_container_member(e, container))
			continue;
		sysfs_free(sra);
		sra = sysfs_read(-1, e->devnum, GET_VERSION);
		if (!sra) {
			pr_err("failed to read sysfs for subarray%s\n",
			       to_subarray(e, container));
			break;
		}
		/* can't reshape an array that we can't monitor */
		if (sra->text_version[0] == '-')
			break;

		if (freeze && sysfs_freeze_array(sra) < 1)
			break;
		/* flag this array to not be modified by mdmon (close race with
		 * takeover in reshape case and spare reassignment in the
		 * auto-rebuild case)
		 */
		if (block_subarray(sra))
			break;
		ping_monitor(container);

		/* check that we did not race with recovery */
		if ((freeze &&
		     !sysfs_attribute_available(sra, NULL, "sync_action")) ||
		    (freeze &&
		     sysfs_attribute_available(sra, NULL, "sync_action") &&
		     sysfs_get_str(sra, NULL, "sync_action", buf, 20) > 0 &&
		     strcmp(buf, "frozen\n") == 0))
			/* pass */;
		else {
			unblock_subarray(sra, 0);
			break;
		}
		/* Double check against races - there should be no spares
		 * or part-spares
		 */
		sysfs_free(sra);
		sra = sysfs_read(-1, e->devnum, GET_DEVS | GET_STATE);
		if (sra && sra->array.spare_disks > 0) {
			unblock_subarray(sra, freeze);
			break;
		}
	}

	if (e) {
		pr_err("failed to freeze subarray%s\n",
			to_subarray(e, container));

		/* thaw the partially frozen container */
		for (e2 = ent; e2 && e2 != e; e2 = e2->next) {
			if (!is_container_member(e2, container))
				continue;
			sysfs_free(sra);
			sra = sysfs_read(-1, e2->devnum, GET_VERSION);
			if (unblock_subarray(sra, freeze))
				pr_err("Failed to unfreeze %s\n", e2->dev);
		}

		ping_monitor(container); /* cleared frozen */
		rv = -1;
	}

	sysfs_free(sra);
	free_mdstat(ent);

	return rv;
}

void unblock_monitor(char *container, const int unfreeze)
{
	struct mdstat_ent *ent, *e;
	struct mdinfo *sra = NULL;
	int to_ping = 0;

	ent = mdstat_read(0, 0);
	if (!ent) {
		pr_err("failed to read /proc/mdstat while unblocking container\n");
		return;
	}

	/* unfreeze container contents */
	for (e = ent; e; e = e->next) {
		if (!is_container_member(e, container))
			continue;
		sysfs_free(sra);
		sra = sysfs_read(-1, e->devnum, GET_VERSION|GET_LEVEL);
		if (!sra)
			continue;
		if (sra->array.level > 0)
			to_ping++;
		if (unblock_subarray(sra, unfreeze))
			pr_err("Failed to unfreeze %s\n", e->dev);
	}
	if (to_ping)
		ping_monitor(container);

	sysfs_free(sra);
	free_mdstat(ent);
}


/* give the manager a chance to view the updated container state.  This
 * would naturally happen due to the manager noticing a change in
 * /proc/mdstat; however, pinging encourages this detection to happen
 * while an exclusive open() on the container is active
 */
int ping_manager(char *devname)
{
	int sfd = connect_monitor(devname);
	struct metadata_update msg = { .len = -1 };
	int err = 0;

	if (sfd < 0)
		return sfd;

	err = send_message(sfd, &msg, 20);

	/* check the reply */
	if (!err && wait_reply(sfd, 20) != 0)
		err = -1;

	close(sfd);
	return err;
}

/* using takeover operation for grow purposes, mdadm has to be sure
 * that mdmon processes all updates, and if necessary it will be closed
 * at takeover to raid0 operation
  */
void flush_mdmon(char *container)
{
	ping_manager(container);
	ping_monitor(container);
}
Commit	Line	Data
f7dd881f DW	1	/*
	2	* Copyright (C) 2008 Intel Corporation
	3	*
	4	* mdmon socket / message handling
	5	*
	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.
	9	*
	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
	13	* more details.
	14	*
	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.
	18	*/
	19	#ifndef _GNU_SOURCE
	20	#define _GNU_SOURCE
	21	#endif
	22	#include <unistd.h>
	23	#include <stdio.h>
	24	#include <string.h>
	25	#include <stdlib.h>
	26	#include <errno.h>
	27	#include <fcntl.h>
	28	#include <sys/types.h>
	29	#include <sys/socket.h>
	30	#include <sys/un.h>
	31	#include "mdadm.h"
bfa44e2e	32	#include "mdmon.h"
f7dd881f	33
bfa44e2e NB	34	static const __u32 start_magic = 0x5a5aa5a5;
	35	static const __u32 end_magic = 0xa5a55a5a;
	36
	37	static int send_buf(int fd, const void* buf, int len, int tmo)
f7dd881f	38	{
bfa44e2e NB	39	fd_set set;
	40	int rv;
	41	struct timeval timeout = {tmo, 0};
	42	struct timeval *ptmo = tmo ? &timeout : NULL;
	43
	44	while (len) {
	45	FD_ZERO(&set);
	46	FD_SET(fd, &set);
	47	rv = select(fd+1, NULL, &set, NULL, ptmo);
	48	if (rv <= 0)
	49	return -1;
	50	rv = write(fd, buf, len);
	51	if (rv <= 0)
	52	return -1;
	53	len -= rv;
	54	buf += rv;
	55	}
	56	return 0;
	57	}
f7dd881f	58
bfa44e2e NB	59	static int recv_buf(int fd, void* buf, int len, int tmo)
	60	{
	61	fd_set set;
	62	int rv;
	63	struct timeval timeout = {tmo, 0};
	64	struct timeval *ptmo = tmo ? &timeout : NULL;
	65
	66	while (len) {
	67	FD_ZERO(&set);
	68	FD_SET(fd, &set);
	69	rv = select(fd+1, &set, NULL, NULL, ptmo);
	70	if (rv <= 0)
	71	return -1;
	72	rv = read(fd, buf, len);
	73	if (rv <= 0)
	74	return -1;
	75	len -= rv;
	76	buf += rv;
	77	}
	78	return 0;
f7dd881f DW	79	}
	80
	81
bfa44e2e	82	int send_message(int fd, struct metadata_update *msg, int tmo)
f7dd881f	83	{
313a4a82	84	__s32 len = msg->len;
bfa44e2e NB	85	int rv;
	86
	87	rv = send_buf(fd, &start_magic, 4, tmo);
	88	rv = rv ?: send_buf(fd, &len, 4, tmo);
313a4a82	89	if (len > 0)
bfa44e2e NB	90	rv = rv ?: send_buf(fd, msg->buf, msg->len, tmo);
	91	rv = send_buf(fd, &end_magic, 4, tmo);
	92
	93	return rv;
f7dd881f DW	94	}
f7dd881f DW	95
bfa44e2e	96	int receive_message(int fd, struct metadata_update *msg, int tmo)
f7dd881f	97	{
bfa44e2e	98	__u32 magic;
313a4a82	99	__s32 len;
bfa44e2e NB	100	int rv;
	101
	102	rv = recv_buf(fd, &magic, 4, tmo);
	103	if (rv < 0 \|\| magic != start_magic)
	104	return -1;
	105	rv = recv_buf(fd, &len, 4, tmo);
	106	if (rv < 0 \|\| len > MSG_MAX_LEN)
f7dd881f	107	return -1;
313a4a82	108	if (len > 0) {
503975b9	109	msg->buf = xmalloc(len);
bfa44e2e NB	110	rv = recv_buf(fd, msg->buf, len, tmo);
	111	if (rv < 0) {
	112	free(msg->buf);
	113	return -1;
	114	}
	115	} else
	116	msg->buf = NULL;
	117	rv = recv_buf(fd, &magic, 4, tmo);
	118	if (rv < 0 \|\| magic != end_magic) {
	119	free(msg->buf);
	120	return -1;
	121	}
	122	msg->len = len;
	123	return 0;
f7dd881f DW	124	}
f7dd881f DW	125
bfa44e2e	126	int ack(int fd, int tmo)
f7dd881f	127	{
bfa44e2e	128	struct metadata_update msg = { .len = 0 };
f7dd881f DW	129
	130	return send_message(fd, &msg, tmo);
	131	}
	132
bfa44e2e	133	int wait_reply(int fd, int tmo)
f7dd881f	134	{
bfa44e2e	135	struct metadata_update msg;
bc77ed53 DW	136	int err = receive_message(fd, &msg, tmo);
	137
	138	/* mdmon sent extra data, but caller only cares that we got a
	139	* successful reply
	140	*/
	141	if (err == 0 && msg.len > 0)
	142	free(msg.buf);
	143
	144	return err;
f7dd881f DW	145	}
f7dd881f DW	146
f7dd881f DW	147	int connect_monitor(char *devname)
	148	{
	149	char path[100];
	150	int sfd;
	151	long fl;
	152	struct sockaddr_un addr;
c94709e8 DW	153	int pos;
	154	char *c;
	155
753cf905	156	pos = sprintf(path, "%s/", MDMON_DIR);
c94709e8 DW	157	if (is_subarray(devname)) {
	158	devname++;
	159	c = strchr(devname, '/');
	160	if (!c)
	161	return -1;
	162	snprintf(&path[pos], c - devname + 1, "%s", devname);
	163	pos += c - devname;
	164	} else
	165	pos += sprintf(&path[pos], "%s", devname);
	166	sprintf(&path[pos], ".sock");
f7dd881f	167
f7dd881f DW	168	sfd = socket(PF_LOCAL, SOCK_STREAM, 0);
	169	if (sfd < 0)
	170	return -1;
	171
	172	addr.sun_family = PF_LOCAL;
	173	strcpy(addr.sun_path, path);
	174	if (connect(sfd, &addr, sizeof(addr)) < 0) {
	175	close(sfd);
	176	return -1;
	177	}
	178
	179	fl = fcntl(sfd, F_GETFL, 0);
	180	fl \|= O_NONBLOCK;
	181	fcntl(sfd, F_SETFL, fl);
	182
	183	return sfd;
	184	}
	185
9f1da824	186	int fping_monitor(int sfd)
f7dd881f	187	{
f7dd881f DW	188	int err = 0;
	189
	190	if (sfd < 0)
	191	return sfd;
	192
	193	/* try to ping existing socket */
eb2c876f	194	if (ack(sfd, 20) != 0)
f7dd881f DW	195	err = -1;
	196
	197	/* check the reply */
eb2c876f	198	if (!err && wait_reply(sfd, 20) != 0)
f7dd881f DW	199	err = -1;
f7dd881f DW	200
9f1da824 DW	201	return err;
	202	}
	203
9f1da824 DW	204	/* give the monitor a chance to update the metadata */
	205	int ping_monitor(char *devname)
	206	{
	207	int sfd = connect_monitor(devname);
b36c8935 JS	208	int err;
	209
	210	if (sfd >= 0) {
	211	err = fping_monitor(sfd);
	212	close(sfd);
	213	} else
	214	err = -1;
9f1da824	215
f7dd881f DW	216	return err;
f7dd881f DW	217	}
313a4a82	218
983fff45 AK	219	/* ping monitor using device number */
	220	int ping_monitor_by_id(int devnum)
	221	{
	222	int err = -1;
	223	char *container = devnum2devname(devnum);
	224
	225	if (container) {
	226	err = ping_monitor(container);
	227	free(container);
	228	}
	229
	230	return err;
	231	}
	232
bc77ed53 DW	233	static char ping_monitor_version(char devname)
	234	{
	235	int sfd = connect_monitor(devname);
	236	struct metadata_update msg;
	237	int err = 0;
	238
	239	if (sfd < 0)
	240	return NULL;
	241
	242	if (ack(sfd, 20) != 0)
	243	err = -1;
	244
	245	if (!err && receive_message(sfd, &msg, 20) != 0)
	246	err = -1;
	247
	248	close(sfd);
	249
	250	if (err \|\| !msg.len \|\| !msg.buf)
	251	return NULL;
	252	return msg.buf;
	253	}
	254
2a093697	255	int unblock_subarray(struct mdinfo *sra, const int unfreeze)
bc77ed53 DW	256	{
	257	char buf[64];
	258	int rc = 0;
	259
	260	if (sra) {
	261	sprintf(buf, "external:%s\n", sra->text_version);
	262	buf[9] = '/';
	263	} else
	264	buf[9] = '-';
	265
	266	if (buf[9] == '-' \|\|
	267	sysfs_set_str(sra, NULL, "metadata_version", buf) \|\|
	268	(unfreeze &&
	269	sysfs_attribute_available(sra, NULL, "sync_action") &&
	270	sysfs_set_str(sra, NULL, "sync_action", "idle")))
	271	rc = -1;
	272	return rc;
	273	}
	274
2a093697 AK	275	int block_subarray(struct mdinfo *sra)
	276	{
	277	char buf[64];
	278	int rc = 0;
	279
	280	sprintf(buf, "external:%s\n", sra->text_version);
	281	buf[9] = '-';
	282	if (sysfs_set_str(sra, NULL, "metadata_version", buf))
	283	rc = -1;
	284
	285	return rc;
	286	}
7aa437c2 AK	287
	288	/* check mdmon version if it supports
	289	* array blocking mechanism
	290	*/
	291	int check_mdmon_version(char *container)
	292	{
	293	char *version = NULL;
	294	int devnum = devname2devnum(container);
	295
	296	if (!mdmon_running(devnum)) {
	297	/* if mdmon is not active we assume that any instance that is
	298	* later started will match the current mdadm version, if this
	299	* assumption is violated we may inadvertantly rebuild an array
	300	* that was meant for reshape, or start rebuild on a spare that
	301	* was to be moved to another container
	302	*/
	303	/* pass */;
	304	} else {
	305	int ver;
	306
	307	version = ping_monitor_version(container);
	308	ver = version ? mdadm_version(version) : -1;
	309	free(version);
	310	if (ver < 3002000) {
e7b84f9d N	311	pr_err("mdmon instance for %s cannot be disabled\n",
e7b84f9d N	312	container);
7aa437c2 AK	313	return -1;
	314	}
	315	}
	316
	317	return 0;
	318	}
	319
bc77ed53 DW	320	/**
	321	* block_monitor - prevent mdmon spare assignment
	322	* @container - container to block
	323	* @freeze - flag to additionally freeze sync_action
	324	*
	325	* This is used by the reshape code to freeze the container, and the
746a6567 N	326	* auto-rebuild implementation to atomically move spares.
	327	* In both cases we need to stop mdmon from assigning spares to replace
	328	* failed devices as we might have other plans for the spare.
	329	* For the reshape case we also need to 'freeze' sync_action so that
	330	* no recovery happens until we have fully prepared for the reshape.
	331	*
	332	* We tell mdmon that the array is frozen by marking the 'metadata' name
	333	* with a leading '-'. The previously told mdmon "Don't make this array
	334	* read/write, leave it readonly". Now it means a more general "Don't
	335	* reconfigure this array at all".
	336	* As older versions of mdmon (which might run from initrd) don't understand
	337	* this, we first check that the running mdmon is new enough.
bc77ed53 DW	338	*/
	339	int block_monitor(char *container, const int freeze)
	340	{
bc77ed53 DW	341	struct mdstat_ent ent, e, *e2;
bc77ed53 DW	342	struct mdinfo *sra = NULL;
bc77ed53 DW	343	char buf[64];
	344	int rv = 0;
	345
7aa437c2 AK	346	if (check_mdmon_version(container))
7aa437c2 AK	347	return -1;
bc77ed53 DW	348
	349	ent = mdstat_read(0, 0);
	350	if (!ent) {
e7b84f9d	351	pr_err("failed to read /proc/mdstat while disabling mdmon\n");
bc77ed53 DW	352	return -1;
	353	}
	354
	355	/* freeze container contents */
	356	for (e = ent; e; e = e->next) {
	357	if (!is_container_member(e, container))
	358	continue;
	359	sysfs_free(sra);
	360	sra = sysfs_read(-1, e->devnum, GET_VERSION);
	361	if (!sra) {
e7b84f9d N	362	pr_err("failed to read sysfs for subarray%s\n",
e7b84f9d N	363	to_subarray(e, container));
bc77ed53 DW	364	break;
	365	}
	366	/* can't reshape an array that we can't monitor */
	367	if (sra->text_version[0] == '-')
	368	break;
	369
	370	if (freeze && sysfs_freeze_array(sra) < 1)
	371	break;
	372	/* flag this array to not be modified by mdmon (close race with
	373	* takeover in reshape case and spare reassignment in the
	374	* auto-rebuild case)
	375	*/
2a093697	376	if (block_subarray(sra))
bc77ed53 DW	377	break;
	378	ping_monitor(container);
	379
	380	/* check that we did not race with recovery */
	381	if ((freeze &&
	382	!sysfs_attribute_available(sra, NULL, "sync_action")) \|\|
	383	(freeze &&
	384	sysfs_attribute_available(sra, NULL, "sync_action") &&
	385	sysfs_get_str(sra, NULL, "sync_action", buf, 20) > 0 &&
	386	strcmp(buf, "frozen\n") == 0))
	387	/* pass */;
885f9845 N	388	else {
885f9845 N	389	unblock_subarray(sra, 0);
bc77ed53	390	break;
885f9845 N	391	}
	392	/* Double check against races - there should be no spares
	393	* or part-spares
	394	*/
	395	sysfs_free(sra);
	396	sra = sysfs_read(-1, e->devnum, GET_DEVS \| GET_STATE);
	397	if (sra && sra->array.spare_disks > 0) {
	398	unblock_subarray(sra, freeze);
	399	break;
	400	}
bc77ed53 DW	401	}
	402
	403	if (e) {
e7b84f9d	404	pr_err("failed to freeze subarray%s\n",
bc77ed53 DW	405	to_subarray(e, container));
	406
	407	/* thaw the partially frozen container */
	408	for (e2 = ent; e2 && e2 != e; e2 = e2->next) {
	409	if (!is_container_member(e2, container))
	410	continue;
	411	sysfs_free(sra);
	412	sra = sysfs_read(-1, e2->devnum, GET_VERSION);
	413	if (unblock_subarray(sra, freeze))
e7b84f9d	414	pr_err("Failed to unfreeze %s\n", e2->dev);
bc77ed53 DW	415	}
	416
	417	ping_monitor(container); /* cleared frozen */
	418	rv = -1;
	419	}
	420
	421	sysfs_free(sra);
	422	free_mdstat(ent);
bc77ed53 DW	423
	424	return rv;
	425	}
	426
	427	void unblock_monitor(char *container, const int unfreeze)
	428	{
	429	struct mdstat_ent ent, e;
	430	struct mdinfo *sra = NULL;
5158aef1	431	int to_ping = 0;
bc77ed53 DW	432
	433	ent = mdstat_read(0, 0);
	434	if (!ent) {
e7b84f9d	435	pr_err("failed to read /proc/mdstat while unblocking container\n");
bc77ed53 DW	436	return;
	437	}
	438
	439	/* unfreeze container contents */
	440	for (e = ent; e; e = e->next) {
	441	if (!is_container_member(e, container))
	442	continue;
	443	sysfs_free(sra);
5158aef1	444	sra = sysfs_read(-1, e->devnum, GET_VERSION\|GET_LEVEL);
29b59ca5 JS	445	if (!sra)
29b59ca5 JS	446	continue;
5158aef1 AK	447	if (sra->array.level > 0)
5158aef1 AK	448	to_ping++;
bc77ed53	449	if (unblock_subarray(sra, unfreeze))
e7b84f9d	450	pr_err("Failed to unfreeze %s\n", e->dev);
bc77ed53	451	}
5158aef1 AK	452	if (to_ping)
5158aef1 AK	453	ping_monitor(container);
bc77ed53 DW	454
	455	sysfs_free(sra);
	456	free_mdstat(ent);
	457	}
	458
	459
	460
313a4a82 DW	461	/* give the manager a chance to view the updated container state. This
	462	* would naturally happen due to the manager noticing a change in
	463	* /proc/mdstat; however, pinging encourages this detection to happen
	464	* while an exclusive open() on the container is active
	465	*/
	466	int ping_manager(char *devname)
	467	{
	468	int sfd = connect_monitor(devname);
	469	struct metadata_update msg = { .len = -1 };
	470	int err = 0;
	471
	472	if (sfd < 0)
	473	return sfd;
	474
	475	err = send_message(sfd, &msg, 20);
	476
	477	/* check the reply */
	478	if (!err && wait_reply(sfd, 20) != 0)
	479	err = -1;
	480
	481	close(sfd);
	482	return err;
	483	}
78340e26 AK	484
	485	/* using takeover operation for grow purposes, mdadm has to be sure
	486	* that mdmon processes all updates, and if necessary it will be closed
	487	* at takeover to raid0 operation
	488	*/
	489	void flush_mdmon(char *container)
	490	{
	491	ping_manager(container);
	492	ping_monitor(container);
	493	}