X-Git-Url: http://git.ipfire.org/?a=blobdiff_plain;f=msg.c;h=45cd45040a6126c22eb2bb2bfdf193cc7357790d;hb=30e19bf805563305068ec856ab24cf2f350c44f8;hp=78fd7f7e26380c9c05e6392438fa2a93ce01b3ad;hpb=37ea3936a696c2b102963ba5117165ef6be8d4b4;p=thirdparty%2Fmdadm.git

diff --git a/msg.c b/msg.c
index 78fd7f7e..45cd4504 100644
--- a/msg.c
+++ b/msg.c
@@ -1,7 +1,7 @@
 /*
  * Copyright (C) 2008 Intel Corporation
  *
- * 	mdmon socket / message handling
+ *	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,
@@ -78,15 +78,14 @@ static int recv_buf(int fd, void* buf, int len, int tmo)
 	return 0;
 }
 
-
 int send_message(int fd, struct metadata_update *msg, int tmo)
 {
-	__u32 len = msg->len;
+	__s32 len = msg->len;
 	int rv;
 
 	rv = send_buf(fd, &start_magic, 4, tmo);
 	rv = rv ?: send_buf(fd, &len, 4, tmo);
-	if (len)
+	if (len > 0)
 		rv = rv ?: send_buf(fd, msg->buf, msg->len, tmo);
 	rv = send_buf(fd, &end_magic, 4, tmo);
 
@@ -96,7 +95,7 @@ int send_message(int fd, struct metadata_update *msg, int tmo)
 int receive_message(int fd, struct metadata_update *msg, int tmo)
 {
 	__u32 magic;
-	__u32 len;
+	__s32 len;
 	int rv;
 
 	rv = recv_buf(fd, &magic, 4, tmo);
@@ -105,10 +104,8 @@ int receive_message(int fd, struct metadata_update *msg, int tmo)
 	rv = recv_buf(fd, &len, 4, tmo);
 	if (rv < 0 || len > MSG_MAX_LEN)
 		return -1;
-	if (len) {
-		msg->buf = malloc(len);
-		if (msg->buf == NULL)
-			return -1;
+	if (len > 0) {
+		msg->buf = xmalloc(len);
 		rv = recv_buf(fd, msg->buf, len, tmo);
 		if (rv < 0) {
 			free(msg->buf);
@@ -135,7 +132,15 @@ int ack(int fd, int tmo)
 int wait_reply(int fd, int tmo)
 {
 	struct metadata_update msg;
-	return receive_message(fd, &msg, tmo);
+	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)
@@ -144,15 +149,28 @@ int connect_monitor(char *devname)
 	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");
 
-	sprintf(path, "/var/run/mdadm/%s.sock", devname);
 	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) {
+	if (connect(sfd, (struct sockaddr*)&addr, sizeof(addr)) < 0) {
 		close(sfd);
 		return -1;
 	}
@@ -164,9 +182,8 @@ int connect_monitor(char *devname)
 	return sfd;
 }
 
-int ping_monitor(char *devname)
+int fping_monitor(int sfd)
 {
-	int sfd = connect_monitor(devname);
 	int err = 0;
 
 	if (sfd < 0)
@@ -176,6 +193,269 @@ int ping_monitor(char *devname)
 	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;
+}
+
+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;
+
+	if (!mdmon_running(container)) {
+		/* 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->devnm, 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->devnm, 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->devnm, GET_VERSION);
+			if (unblock_subarray(sra, freeze))
+				pr_err("Failed to unfreeze %s\n", e2->devnm);
+		}
+
+		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->devnm, 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->devnm);
+	}
+	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;
@@ -183,3 +463,13 @@ int ping_monitor(char *devname)
 	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);
+}