Adding upstream version 4.2.upstream/4.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 475 insertions, 0 deletions

diff --git a/msg.c b/msg.c
new file mode 100644
index 0000000..45cd450
--- /dev/null
+++ b/msg.c
@@ -0,0 +1,475 @@
+/*
+ * 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, (struct sockaddr*)&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;
+}
+
+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;
+
+	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);
+}