Please welcome HAST - Highly Avalable Storage.

HAST allows to transparently store data on two physically separated machines
connected over the TCP/IP network. HAST works in Primary-Secondary
(Master-Backup, Master-Slave) configuration, which means that only one of the
cluster nodes can be active at any given time. Only Primary node is able to
handle I/O requests to HAST-managed devices. Currently HAST is limited to two
cluster nodes in total.

HAST operates on block level - it provides disk-like devices in /dev/hast/
directory for use by file systems and/or applications. Working on block level
makes it transparent for file systems and applications. There in no difference
between using HAST-provided device and raw disk, partition, etc. All of them
are just regular GEOM providers in FreeBSD.

For more information please consult hastd(8), hastctl(8) and hast.conf(5)
manual pages, as well as http://wiki.FreeBSD.org/HAST.

Sponsored by:	FreeBSD Foundation
Sponsored by:	OMCnet Internet Service GmbH
Sponsored by:	TransIP BV

1 files changed, 222 insertions, 0 deletions

diff --git a/sbin/hastd/metadata.c b/sbin/hastd/metadata.c
new file mode 100644
index 0000000..9bca66b
--- /dev/null
+++ b/sbin/hastd/metadata.c
@@ -0,0 +1,222 @@
+/*-
+ * Copyright (c) 2009-2010 The FreeBSD Foundation
+ * All rights reserved.
+ *
+ * This software was developed by Pawel Jakub Dawidek under sponsorship from
+ * the FreeBSD Foundation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <strings.h>
+#include <unistd.h>
+
+#include <ebuf.h>
+#include <nv.h>
+#include <pjdlog.h>
+#include <subr.h>
+
+#include "metadata.h"
+
+int
+metadata_read(struct hast_resource *res, bool openrw)
+{
+	unsigned char *buf;
+	struct ebuf *eb;
+	struct nv *nv;
+	ssize_t done;
+	const char *str;
+	int rerrno;
+	bool opened_here;
+
+	opened_here = false;
+	rerrno = 0;
+
+	/*
+	 * Is this first metadata_read() call for this resource?
+	 */
+	if (res->hr_localfd == -1) {
+		if (provinfo(res, openrw) < 0) {
+			rerrno = errno;
+			goto fail;
+		}
+		opened_here = true;
+		pjdlog_debug(1, "Obtained info about %s.", res->hr_localpath);
+		if (openrw) {
+			if (flock(res->hr_localfd, LOCK_EX | LOCK_NB) < 0) {
+				rerrno = errno;
+				if (errno == EOPNOTSUPP) {
+					pjdlog_warning("Unable to lock %s (operation not supported), but continuing.",
+					    res->hr_localpath);
+				} else {
+					pjdlog_errno(LOG_ERR,
+					    "Unable to lock %s",
+					    res->hr_localpath);
+					goto fail;
+				}
+			}
+			pjdlog_debug(1, "Locked %s.", res->hr_localpath);
+		}
+	}
+
+	eb = ebuf_alloc(METADATA_SIZE);
+	if (eb == NULL) {
+		rerrno = errno;
+		pjdlog_errno(LOG_ERR,
+		    "Unable to allocate memory to read metadata");
+		goto fail;
+	}
+	if (ebuf_add_tail(eb, NULL, METADATA_SIZE) < 0) {
+		rerrno = errno;
+		pjdlog_errno(LOG_ERR,
+		    "Unable to allocate memory to read metadata");
+		goto fail;
+	}
+	buf = ebuf_data(eb, NULL);
+	assert(buf != NULL);
+	done = pread(res->hr_localfd, buf, METADATA_SIZE, 0);
+	if (done < 0 || done != METADATA_SIZE) {
+		rerrno = errno;
+		pjdlog_errno(LOG_ERR, "Unable to read metadata");
+		ebuf_free(eb);
+		goto fail;
+	}
+	nv = nv_ntoh(eb);
+	if (nv == NULL) {
+		rerrno = errno;
+		pjdlog_errno(LOG_ERR, "Metadata read from %s is invalid",
+		    res->hr_localpath);
+		ebuf_free(eb);
+		goto fail;
+	}
+
+	str = nv_get_string(nv, "resource");
+	if (strcmp(str, res->hr_name) != 0) {
+		pjdlog_error("Provider %s is not part of resource %s.",
+		    res->hr_localpath, res->hr_name);
+		nv_free(nv);
+		goto fail;
+	}
+
+	res->hr_datasize = nv_get_uint64(nv, "datasize");
+	res->hr_extentsize = (int)nv_get_uint32(nv, "extentsize");
+	res->hr_keepdirty = (int)nv_get_uint32(nv, "keepdirty");
+	res->hr_localoff = nv_get_uint64(nv, "offset");
+	res->hr_resuid = nv_get_uint64(nv, "resuid");
+	if (res->hr_role != HAST_ROLE_PRIMARY) {
+		/* Secondary or init role. */
+		res->hr_secondary_localcnt = nv_get_uint64(nv, "localcnt");
+		res->hr_secondary_remotecnt = nv_get_uint64(nv, "remotecnt");
+	}
+	if (res->hr_role != HAST_ROLE_SECONDARY) {
+		/* Primary or init role. */
+		res->hr_primary_localcnt = nv_get_uint64(nv, "localcnt");
+		res->hr_primary_remotecnt = nv_get_uint64(nv, "remotecnt");
+	}
+	str = nv_get_string(nv, "prevrole");
+	if (str != NULL) {
+		if (strcmp(str, "primary") == 0)
+			res->hr_previous_role = HAST_ROLE_PRIMARY;
+		else if (strcmp(str, "secondary") == 0)
+			res->hr_previous_role = HAST_ROLE_SECONDARY;
+	}
+
+	if (nv_error(nv) != 0) {
+		errno = rerrno = nv_error(nv);
+		pjdlog_errno(LOG_ERR, "Unable to read metadata from %s",
+		    res->hr_localpath);
+		nv_free(nv);
+		goto fail;
+	}
+	return (0);
+fail:
+	if (opened_here) {
+		close(res->hr_localfd);
+		res->hr_localfd = -1;
+	}
+	errno = rerrno;
+	return (-1);
+}
+
+int
+metadata_write(struct hast_resource *res)
+{
+	struct ebuf *eb;
+	struct nv *nv;
+	unsigned char *buf, *ptr;
+	size_t size;
+	ssize_t done;
+
+	buf = calloc(1, METADATA_SIZE);
+	if (buf == NULL) {
+		pjdlog_error("Unable to allocate %zu bytes for metadata.",
+		    (size_t)METADATA_SIZE);
+		return (-1);
+	}
+
+	nv = nv_alloc();
+	nv_add_string(nv, res->hr_name, "resource");
+	nv_add_uint64(nv, (uint64_t)res->hr_datasize, "datasize");
+	nv_add_uint32(nv, (uint32_t)res->hr_extentsize, "extentsize");
+	nv_add_uint32(nv, (uint32_t)res->hr_keepdirty, "keepdirty");
+	nv_add_uint64(nv, (uint64_t)res->hr_localoff, "offset");
+	nv_add_uint64(nv, res->hr_resuid, "resuid");
+	if (res->hr_role == HAST_ROLE_PRIMARY ||
+	    res->hr_role == HAST_ROLE_INIT) {
+		nv_add_uint64(nv, res->hr_primary_localcnt, "localcnt");
+		nv_add_uint64(nv, res->hr_primary_remotecnt, "remotecnt");
+	} else /* if (res->hr_role == HAST_ROLE_SECONDARY) */ {
+		assert(res->hr_role == HAST_ROLE_SECONDARY);
+		nv_add_uint64(nv, res->hr_secondary_localcnt, "localcnt");
+		nv_add_uint64(nv, res->hr_secondary_remotecnt, "remotecnt");
+	}
+	nv_add_string(nv, role2str(res->hr_role), "prevrole");
+	if (nv_error(nv) != 0) {
+		pjdlog_error("Unable to create metadata.");
+		goto fail;
+	}
+	res->hr_previous_role = res->hr_role;
+	eb = nv_hton(nv);
+	assert(eb != NULL);
+	ptr = ebuf_data(eb, &size);
+	assert(ptr != NULL);
+	assert(size < METADATA_SIZE);
+	bcopy(ptr, buf, size);
+	done = pwrite(res->hr_localfd, buf, METADATA_SIZE, 0);
+	if (done < 0 || done != METADATA_SIZE) {
+		pjdlog_errno(LOG_ERR, "Unable to write metadata");
+		goto fail;
+	}
+
+	return (0);
+fail:
+	free(buf);
+	nv_free(nv);
+	return (-1);
+}