X-Git-Url: http://git.ozlabs.org/?p=petitboot;a=blobdiff_plain;f=discover%2Fdevice-handler.c;h=38584440801963e193a7aee2ad9c7a62cb89f9d3;hp=f1845a9479f4de878bfab4f5d6dcecbfcb1e69b1;hb=03fe06fa71f065e918c46a65e6a45e76063a07eb;hpb=f7ace4cc96390a26b0f6c5ee4ff8fe6d7d62ecd0

diff --git a/discover/device-handler.c b/discover/device-handler.c
index f1845a9..3858444 100644
--- a/discover/device-handler.c
+++ b/discover/device-handler.c
@@ -5,8 +5,10 @@
 #include <string.h>
 #include <errno.h>
 #include <mntent.h>
+#include <locale.h>
 #include <sys/stat.h>
 #include <sys/wait.h>
+#include <sys/mount.h>
 
 #include <talloc/talloc.h>
 #include <list/list.h>
@@ -15,9 +17,18 @@
 #include <system/system.h>
 #include <process/process.h>
 #include <url/url.h>
+#include <i18n/i18n.h>
+
+#include <sys/sysmacros.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netdb.h>
+#include <arpa/inet.h>
 
 #include "device-handler.h"
 #include "discover-server.h"
+#include "devmapper.h"
+#include "user-event.h"
 #include "platform.h"
 #include "event.h"
 #include "parser.h"
@@ -25,29 +36,64 @@
 #include "paths.h"
 #include "sysinfo.h"
 #include "boot.h"
+#include "udev.h"
+#include "network.h"
+#include "ipmi.h"
+
+enum default_priority {
+	DEFAULT_PRIORITY_REMOTE		= 1,
+	DEFAULT_PRIORITY_LOCAL_FIRST	= 2,
+	DEFAULT_PRIORITY_LOCAL_LAST	= 0xfe,
+	DEFAULT_PRIORITY_DISABLED	= 0xff,
+};
+
+struct progress_info {
+	unsigned int			percentage;
+	unsigned long			size;		/* size in bytes */
+
+	const struct process_info	*procinfo;
+	struct list_item	list;
+};
 
 struct device_handler {
 	struct discover_server	*server;
 	int			dry_run;
 
+	struct pb_udev		*udev;
+	struct network		*network;
+	struct user_event	*user_event;
+
 	struct discover_device	**devices;
 	unsigned int		n_devices;
 
+	struct ramdisk_device	**ramdisks;
+	unsigned int		n_ramdisks;
+
 	struct waitset		*waitset;
 	struct waiter		*timeout_waiter;
 	bool			autoboot_enabled;
 	unsigned int		sec_to_boot;
 
 	struct discover_boot_option *default_boot_option;
+	int			default_boot_option_priority;
+
 	struct list		unresolved_boot_options;
 
 	struct boot_task	*pending_boot;
 	bool			pending_boot_is_default;
+
+	struct list		progress;
+	unsigned int		n_progress;
 };
 
 static int mount_device(struct discover_device *dev);
 static int umount_device(struct discover_device *dev);
 
+static int device_handler_init_sources(struct device_handler *handler);
+static void device_handler_reinit_sources(struct device_handler *handler);
+
+static void device_handler_update_lang(const char *lang);
+
 void discover_context_add_boot_option(struct discover_context *ctx,
 		struct discover_boot_option *boot_option)
 {
@@ -80,6 +126,12 @@ const struct discover_device *device_handler_get_device(
 	return handler->devices[index];
 }
 
+struct network *device_handler_get_network(
+		const struct device_handler *handler)
+{
+	return handler->network;
+}
+
 struct discover_boot_option *discover_boot_option_create(
 		struct discover_context *ctx,
 		struct discover_device *device)
@@ -187,17 +239,22 @@ static int destroy_device(void *arg)
 }
 
 struct discover_device *discover_device_create(struct device_handler *handler,
-		const char *id)
+		const char *uuid, const char *id)
 {
 	struct discover_device *dev;
 
-	dev = device_lookup_by_id(handler, id);
+	if (uuid)
+		dev = device_lookup_by_uuid(handler, uuid);
+	else
+		dev = device_lookup_by_id(handler, id);
+
 	if (dev)
 		return dev;
 
 	dev = talloc_zero(handler, struct discover_device);
 	dev->device = talloc_zero(dev, struct device);
 	dev->device->id = talloc_strdup(dev->device, id);
+	dev->uuid = talloc_strdup(dev, uuid);
 	list_init(&dev->params);
 	list_init(&dev->boot_options);
 
@@ -259,29 +316,93 @@ struct device_handler *device_handler_init(struct discover_server *server,
 		struct waitset *waitset, int dry_run)
 {
 	struct device_handler *handler;
+	int rc;
 
 	handler = talloc_zero(NULL, struct device_handler);
 	handler->server = server;
 	handler->waitset = waitset;
 	handler->dry_run = dry_run;
-	handler->autoboot_enabled = config_get()->autoboot_enabled;
+	handler->autoboot_enabled = config_autoboot_active(config_get());
 
 	list_init(&handler->unresolved_boot_options);
 
+	list_init(&handler->progress);
+
 	/* set up our mount point base */
 	pb_mkdir_recursive(mount_base());
 
 	parser_init();
 
+	if (config_get()->safe_mode)
+		return handler;
+
+	rc = device_handler_init_sources(handler);
+	if (rc) {
+		talloc_free(handler);
+		return NULL;
+	}
+
 	return handler;
 }
 
+void device_handler_reinit(struct device_handler *handler)
+{
+	struct discover_boot_option *opt, *tmp;
+	struct ramdisk_device *ramdisk;
+	unsigned int i;
+
+	device_handler_cancel_default(handler);
+	/* Cancel any pending non-default boot */
+	if (handler->pending_boot) {
+		boot_cancel(handler->pending_boot);
+		handler->pending_boot = NULL;
+		handler->pending_boot_is_default = false;
+	}
+
+	/* Cancel any remaining async jobs */
+	process_stop_async_all();
+	pending_network_jobs_cancel();
+
+	/* free unresolved boot options */
+	list_for_each_entry_safe(&handler->unresolved_boot_options,
+			opt, tmp, list)
+		talloc_free(opt);
+	list_init(&handler->unresolved_boot_options);
+
+	/* drop all devices */
+	for (i = 0; i < handler->n_devices; i++) {
+		discover_server_notify_device_remove(handler->server,
+				handler->devices[i]->device);
+		ramdisk = handler->devices[i]->ramdisk;
+		talloc_free(handler->devices[i]);
+		talloc_free(ramdisk);
+	}
+
+	talloc_free(handler->devices);
+	handler->devices = NULL;
+	handler->n_devices = 0;
+	talloc_free(handler->ramdisks);
+	handler->ramdisks = NULL;
+	handler->n_ramdisks = 0;
+
+	device_handler_reinit_sources(handler);
+}
+
 void device_handler_remove(struct device_handler *handler,
 		struct discover_device *device)
 {
 	struct discover_boot_option *opt, *tmp;
 	unsigned int i;
 
+	list_for_each_entry_safe(&device->boot_options, opt, tmp, list) {
+		if (opt == handler->default_boot_option) {
+			pb_log("Default option %s cancelled since device removed",
+					opt->option->name);
+			device_handler_cancel_default(handler);
+			break;
+		}
+	}
+
 	for (i = 0; i < handler->n_devices; i++)
 		if (handler->devices[i] == device)
 			break;
@@ -301,6 +422,11 @@ void device_handler_remove(struct device_handler *handler,
 		talloc_free(opt);
 	}
 
+	/* if this is a network device, we have to unregister it from the
+	 * network code */
+	if (device->device->type == DEVICE_TYPE_NETWORK)
+		network_unregister_device(handler->network, device);
+
 	handler->n_devices--;
 	memmove(&handler->devices[i], &handler->devices[i + 1],
 		(handler->n_devices - i) * sizeof(handler->devices[0]));
@@ -314,25 +440,198 @@ void device_handler_remove(struct device_handler *handler,
 	talloc_free(device);
 }
 
-static void boot_status(void *arg, struct boot_status *status)
+void device_handler_status(struct device_handler *handler,
+		struct status *status)
 {
-	struct device_handler *handler = arg;
-
 	discover_server_notify_boot_status(handler->server, status);
 }
 
+static void _device_handler_vstatus(struct device_handler *handler,
+		enum status_type type, const char *fmt, va_list ap)
+{
+	struct status status;
+
+	status.type = type;
+	status.message = talloc_vasprintf(handler, fmt, ap);
+	status.backlog = false;
+
+	device_handler_status(handler, &status);
+
+	talloc_free(status.message);
+}
+
+static void _device_handler_vdevstatus(struct device_handler *handler,
+		struct discover_device *device, enum status_type type,
+		const char *fmt, va_list ap)
+{
+	char *msg;
+
+	msg = talloc_asprintf(handler, "[%s] %s",
+			device ? device->device->id : "unknown", fmt);
+	_device_handler_vstatus(handler, type, msg, ap);
+	talloc_free(msg);
+}
+
+void device_handler_status_dev_info(struct device_handler *handler,
+		struct discover_device *dev, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	_device_handler_vdevstatus(handler, dev, STATUS_INFO, fmt, ap);
+	va_end(ap);
+}
+
+void device_handler_status_dev_err(struct device_handler *handler,
+		struct discover_device *dev, const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	_device_handler_vdevstatus(handler, dev, STATUS_ERROR, fmt, ap);
+	va_end(ap);
+}
+
+void device_handler_status_info(struct device_handler *handler,
+		const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	_device_handler_vstatus(handler, STATUS_INFO, fmt, ap);
+	va_end(ap);
+}
+
+void device_handler_status_err(struct device_handler *handler,
+		const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	_device_handler_vstatus(handler, STATUS_ERROR, fmt, ap);
+	va_end(ap);
+}
+
+void device_handler_status_download(struct device_handler *handler,
+		const struct process_info *procinfo,
+		unsigned int percentage, unsigned int size, char suffix)
+{
+	struct progress_info *p, *progress = NULL;
+	uint64_t current_converted, current = 0;
+	const char *units = " kMGTP";
+	unsigned long size_bytes;
+	char *update = NULL;
+	double total = 0;
+	unsigned int i;
+	int unit = 0;
+
+	list_for_each_entry(&handler->progress, p, list)
+		if (p->procinfo == procinfo)
+			progress = p;
+
+	if (!progress) {
+		pb_log("Registering new progress struct\n");
+		progress = talloc_zero(handler, struct progress_info);
+		if (!progress) {
+			pb_log("Failed to allocate room for progress struct\n");
+			return;
+		}
+		progress->procinfo = procinfo;
+		list_add(&handler->progress, &progress->list);
+		handler->n_progress++;
+	}
+
+	size_bytes = size;
+	for (i = 0; i < strlen(units); i++) {
+		if (units[i] == suffix)
+			break;
+	}
+
+	if (i >= strlen(units)) {
+	    pb_log("Couldn't recognise suffix '%c'\n", suffix);
+	    size_bytes = 0;
+	} else {
+		while (i--)
+			size_bytes <<= 10;
+	}
+
+	progress->percentage = percentage;
+	progress->size = size_bytes;
+
+	/*
+	 * Aggregate the info we have and update status. If a progress struct
+	 * has zero for both percentage and size we assume progress information
+	 * is unavailable and fall back to a generic progress message.
+	 */
+	list_for_each_entry(&handler->progress, p, list) {
+		uint64_t c;
+		double t;
+		if (!p->percentage || !p->size) {
+			update = talloc_asprintf(handler,
+					_("%u downloads in progress..."),
+					handler->n_progress);
+			current = total = 0;
+			break;
+		}
+
+		c = p->size;
+		t = (100 * c) / p->percentage;
+
+		current += c;
+		total += t;
+	}
+
+	if (total) {
+		current_converted = current;
+		while (current_converted >= 1000) {
+			current_converted >>= 10;
+			unit++;
+		}
+		update = talloc_asprintf(handler,
+				_("%u %s downloading: %.0f%% - %lu%cB"),
+				handler->n_progress,
+				ngettext("item", "items", handler->n_progress),
+				(current / total) * 100, current_converted,
+				units[unit]);
+	}
+
+	if (!update) {
+		pb_log("%s: failed to allocate new status\n", __func__);
+	} else {
+		device_handler_status_info(handler, "%s\n", update);
+		talloc_free(update);
+	}
+}
+
+void device_handler_status_download_remove(struct device_handler *handler,
+		struct process_info *procinfo)
+{
+	struct progress_info *p, *tmp;
+
+	list_for_each_entry_safe(&handler->progress, p, tmp, list)
+		if (p->procinfo == procinfo) {
+			list_remove(&p->list);
+			talloc_free(p);
+			handler->n_progress--;
+		}
+}
+
+static void device_handler_boot_status_cb(void *arg, struct status *status)
+{
+	device_handler_status(arg, status);
+}
+
 static void countdown_status(struct device_handler *handler,
 		struct discover_boot_option *opt, unsigned int sec)
 {
-	struct boot_status status;
+	struct status status;
 
-	status.type = BOOT_STATUS_INFO;
-	status.progress = -1;
-	status.detail = NULL;
+	status.type = STATUS_INFO;
 	status.message = talloc_asprintf(handler,
-			"Booting %s in %u sec", opt->option->name, sec);
+			_("Booting in %d sec: %s"), sec, opt->option->name);
+	status.backlog = false;
 
-	discover_server_notify_boot_status(handler->server, &status);
+	device_handler_status(handler, &status);
 
 	talloc_free(status.message);
 }
@@ -363,61 +662,134 @@ static int default_timeout(void *arg)
 
 	pb_log("Timeout expired, booting default option %s\n", opt->option->id);
 
+	platform_pre_boot();
+
 	handler->pending_boot = boot(handler, handler->default_boot_option,
-			NULL, handler->dry_run, boot_status, handler);
+			NULL, handler->dry_run, device_handler_boot_status_cb,
+			handler);
 	handler->pending_boot_is_default = true;
 	return 0;
 }
 
-static bool priority_match(struct boot_priority *prio,
-		struct discover_boot_option *opt)
+struct {
+	enum ipmi_bootdev	ipmi_type;
+	enum device_type	device_type;
+} device_type_map[] = {
+	{ IPMI_BOOTDEV_NETWORK, DEVICE_TYPE_NETWORK },
+	{ IPMI_BOOTDEV_DISK, DEVICE_TYPE_DISK },
+	{ IPMI_BOOTDEV_DISK, DEVICE_TYPE_USB },
+	{ IPMI_BOOTDEV_CDROM, DEVICE_TYPE_OPTICAL },
+};
+
+static bool ipmi_device_type_matches(enum ipmi_bootdev ipmi_type,
+		enum device_type device_type)
 {
-	return prio->type == opt->device->device->type ||
-		prio->type == DEVICE_TYPE_ANY;
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(device_type_map); i++) {
+		if (device_type_map[i].device_type == device_type)
+			return device_type_map[i].ipmi_type == ipmi_type;
+	}
+
+	return false;
 }
 
-static int default_option_priority(struct discover_boot_option *opt)
+static int autoboot_option_priority(const struct config *config,
+				struct discover_boot_option *opt)
 {
-	const struct config *config;
-	struct boot_priority *prio;
+	enum device_type type = opt->device->device->type;
+	const char *uuid = opt->device->uuid;
+	struct autoboot_option *auto_opt;
 	unsigned int i;
 
+	for (i = 0; i < config->n_autoboot_opts; i++) {
+		auto_opt = &config->autoboot_opts[i];
+		if (auto_opt->boot_type == BOOT_DEVICE_UUID)
+			if (!strcmp(auto_opt->uuid, uuid))
+				return DEFAULT_PRIORITY_LOCAL_FIRST + i;
+
+		if (auto_opt->boot_type == BOOT_DEVICE_TYPE)
+			if (auto_opt->type == type ||
+			    auto_opt->type == DEVICE_TYPE_ANY)
+				return DEFAULT_PRIORITY_LOCAL_FIRST + i;
+	}
+
+	return -1;
+}
+
+/*
+ * We have different priorities to resolve conflicts between boot options that
+ * report to be the default for their device. This function assigns a priority
+ * for these options.
+ */
+static enum default_priority default_option_priority(
+		struct discover_boot_option *opt)
+{
+	const struct config *config;
+
 	config = config_get();
 
-	for (i = 0; i < config->n_boot_priorities; i++) {
-		prio = &config->boot_priorities[i];
-		if (priority_match(prio, opt))
-			return prio->priority;
+	/* We give highest priority to IPMI-configured boot options. If
+	 * we have an IPMI bootdev configuration set, then we don't allow
+	 * any other defaults */
+	if (config->ipmi_bootdev) {
+		bool ipmi_match = ipmi_device_type_matches(config->ipmi_bootdev,
+				opt->device->device->type);
+		if (ipmi_match)
+			return DEFAULT_PRIORITY_REMOTE;
+
+		pb_debug("handler: disabled default priority due to "
+				"non-matching IPMI type %x\n",
+				config->ipmi_bootdev);
+		return DEFAULT_PRIORITY_DISABLED;
 	}
 
-	return 0;
+	/* Next, try to match the option against the user-defined autoboot
+	 * options, either by device UUID or type. */
+	if (config->n_autoboot_opts) {
+		int boot_match = autoboot_option_priority(config, opt);
+		if (boot_match > 0)
+			return boot_match;
+	}
+
+	/* If the option didn't match any entry in the array, it is disabled */
+	pb_debug("handler: disabled default priority due to "
+			"non-matching UUID or type\n");
+	return DEFAULT_PRIORITY_DISABLED;
 }
 
 static void set_default(struct device_handler *handler,
 		struct discover_boot_option *opt)
 {
-	int new_prio;
+	enum default_priority cur_prio, new_prio;
 
 	if (!handler->autoboot_enabled)
 		return;
 
+	pb_debug("handler: new default option: %s\n", opt->option->id);
+
 	new_prio = default_option_priority(opt);
 
-	/* A negative priority indicates that we don't want to boot this device
-	 * by default */
-	if (new_prio < 0)
+	/* Anything outside our range prevents a default boot */
+	if (new_prio >= DEFAULT_PRIORITY_DISABLED)
 		return;
 
+	pb_debug("handler: calculated priority %d\n", new_prio);
+
 	/* Resolve any conflicts: if we have a new default option, it only
 	 * replaces the current if it has a higher priority. */
 	if (handler->default_boot_option) {
-		int cur_prio;
 
-		cur_prio = default_option_priority(
-					handler->default_boot_option);
+		cur_prio = handler->default_boot_option_priority;
 
-		if (new_prio > cur_prio) {
+		if (new_prio < cur_prio) {
+			pb_log("handler: new prio %d beats "
+					"old prio %d for %s\n",
+					new_prio, cur_prio,
+					handler->default_boot_option
+						->option->id);
 			handler->default_boot_option = opt;
+			handler->default_boot_option_priority = new_prio;
 			/* extend the timeout a little, so the user sees some
 			 * indication of the change */
 			handler->sec_to_boot += 2;
@@ -428,8 +800,9 @@ static void set_default(struct device_handler *handler,
 
 	handler->sec_to_boot = config_get()->autoboot_timeout_sec;
 	handler->default_boot_option = opt;
+	handler->default_boot_option_priority = new_prio;
 
-	pb_log("Boot option %s set as default, timeout %u sec.\n",
+	pb_log("handler: boot option %s set as default, timeout %u sec.\n",
 	       opt->option->id, handler->sec_to_boot);
 
 	default_timeout(handler);
@@ -448,6 +821,7 @@ static bool __attribute__((used)) boot_option_is_resolved(
 	return resource_is_resolved(opt->boot_image) &&
 		resource_is_resolved(opt->initrd) &&
 		resource_is_resolved(opt->dtb) &&
+		resource_is_resolved(opt->args_sig_file) &&
 		resource_is_resolved(opt->icon);
 }
 
@@ -473,6 +847,8 @@ static bool boot_option_resolve(struct discover_boot_option *opt,
 	return resource_resolve(opt->boot_image, "boot_image", opt, handler) &&
 		resource_resolve(opt->initrd, "initrd", opt, handler) &&
 		resource_resolve(opt->dtb, "dtb", opt, handler) &&
+		resource_resolve(opt->args_sig_file, "args_sig_file", opt,
+			handler) &&
 		resource_resolve(opt->icon, "icon", opt, handler);
 }
 
@@ -487,6 +863,7 @@ static void boot_option_finalise(struct device_handler *handler,
 	assert(!opt->option->dtb_file);
 	assert(!opt->option->icon_file);
 	assert(!opt->option->device_id);
+	assert(!opt->option->args_sig_file);
 
 	if (opt->boot_image)
 		opt->option->boot_image_file = opt->boot_image->url->full;
@@ -496,6 +873,8 @@ static void boot_option_finalise(struct device_handler *handler,
 		opt->option->dtb_file = opt->dtb->url->full;
 	if (opt->icon)
 		opt->option->icon_file = opt->icon->url->full;
+	if (opt->args_sig_file)
+		opt->option->args_sig_file = opt->args_sig_file->url->full;
 
 	opt->option->device_id = opt->device->device->id;
 
@@ -545,64 +924,112 @@ struct discover_context *device_handler_discover_context_create(
 	struct discover_context *ctx;
 
 	ctx = talloc_zero(handler, struct discover_context);
+	ctx->handler = handler;
 	ctx->device = device;
 	list_init(&ctx->boot_options);
 
 	return ctx;
 }
 
-/**
- * context_commit - Commit a temporary discovery context to the handler,
- * and notify the clients about any new options / devices
- */
-void device_handler_discover_context_commit(struct device_handler *handler,
-		struct discover_context *ctx)
+void device_handler_add_device(struct device_handler *handler,
+		struct discover_device *device)
 {
-	struct discover_device *dev = ctx->device;
-	struct discover_boot_option *opt, *tmp;
+	handler->n_devices++;
+	handler->devices = talloc_realloc(handler, handler->devices,
+				struct discover_device *, handler->n_devices);
+	handler->devices[handler->n_devices - 1] = device;
 
-	if (!device_lookup_by_id(handler, dev->device->id))
-		device_handler_add_device(handler, dev);
+	if (device->device->type == DEVICE_TYPE_NETWORK)
+		network_register_device(handler->network, device);
+}
 
-	/* move boot options from the context to the device */
-	list_for_each_entry_safe(&ctx->boot_options, opt, tmp, list) {
-		list_remove(&opt->list);
+void device_handler_add_ramdisk(struct device_handler *handler,
+		const char *path)
+{
+	struct ramdisk_device *dev;
+	unsigned int i;
 
-		if (boot_option_resolve(opt, handler)) {
-			pb_log("boot option %s is resolved, "
-					"sending to clients\n",
-					opt->option->id);
-			list_add_tail(&dev->boot_options, &opt->list);
-			talloc_steal(dev, opt);
-			boot_option_finalise(handler, opt);
-			notify_boot_option(handler, opt);
+	if (!path)
+		return;
+
+	for (i = 0; i < handler->n_ramdisks; i++)
+		if (!strcmp(handler->ramdisks[i]->path, path))
+			return;
+
+	dev = talloc_zero(handler, struct ramdisk_device);
+	if (!dev) {
+		pb_log("Failed to allocate memory to track %s\n", path);
+		return;
+	}
+
+	dev->path = talloc_strdup(handler, path);
+
+	handler->ramdisks = talloc_realloc(handler, handler->ramdisks,
+				struct ramdisk_device *,
+				handler->n_ramdisks + 1);
+	if (!handler->ramdisks) {
+		pb_log("Failed to reallocate memory"
+		       "- ramdisk tracking inconsistent!\n");
+		return;
+	}
+
+	handler->ramdisks[i] = dev;
+	i = handler->n_ramdisks++;
+}
+
+struct ramdisk_device *device_handler_get_ramdisk(
+		struct device_handler *handler)
+{
+	unsigned int i;
+	char *name;
+	dev_t id;
+
+	/* Check if free ramdisk exists */
+	for (i = 0; i < handler->n_ramdisks; i++)
+		if (!handler->ramdisks[i]->snapshot &&
+		    !handler->ramdisks[i]->origin &&
+		    !handler->ramdisks[i]->base)
+			return handler->ramdisks[i];
+
+	/* Otherwise create a new one */
+	name = talloc_asprintf(handler, "/dev/ram%d",
+			handler->n_ramdisks);
+	if (!name) {
+		pb_debug("Failed to allocate memory to name /dev/ram%d",
+			handler->n_ramdisks);
+		return NULL;
+	}
+
+	id = makedev(1, handler->n_ramdisks);
+	if (mknod(name, S_IFBLK, id)) {
+		if (errno == EEXIST) {
+			/* We haven't yet received updates for existing
+			 * ramdisks - add and use this one */
+			pb_debug("Using untracked ramdisk %s\n", name);
 		} else {
-			if (!opt->source->resolve_resource) {
-				pb_log("parser %s gave us an unresolved "
-					"resource (%s), but no way to "
-					"resolve it\n",
-					opt->source->name, opt->option->id);
-				talloc_free(opt);
-			} else {
-				pb_log("boot option %s is unresolved, "
-						"adding to queue\n",
-						opt->option->id);
-				list_add(&handler->unresolved_boot_options,
-						&opt->list);
-				talloc_steal(handler, opt);
-			}
+			pb_log("Failed to create new ramdisk %s: %s\n",
+			       name, strerror(errno));
+			return NULL;
 		}
 	}
+	device_handler_add_ramdisk(handler, name);
+	talloc_free(name);
+
+	return handler->ramdisks[i];
 }
 
-void device_handler_add_device(struct device_handler *handler,
-		struct discover_device *device)
+void device_handler_release_ramdisk(struct discover_device *device)
 {
-	handler->n_devices++;
-	handler->devices = talloc_realloc(handler, handler->devices,
-				struct discover_device *, handler->n_devices);
-	handler->devices[handler->n_devices - 1] = device;
+	struct ramdisk_device *ramdisk = device->ramdisk;
+
+	talloc_free(ramdisk->snapshot);
+	talloc_free(ramdisk->origin);
+	talloc_free(ramdisk->base);
 
+	ramdisk->snapshot = ramdisk->origin = ramdisk->base = NULL;
+	ramdisk->sectors = 0;
+
+	device->ramdisk = NULL;
 }
 
 /* Start discovery on a hotplugged device. The device will be in our devices
@@ -614,7 +1041,14 @@ int device_handler_discover(struct device_handler *handler,
 	struct discover_context *ctx;
 	int rc;
 
-	process_boot_option_queue(handler);
+	device_handler_status_dev_info(handler, dev,
+		/*
+		 * TRANSLATORS: this string will be passed the type of the
+		 * device (eg "disk" or "network"), which will be translated
+		 * accordingly.
+		 */
+		_("Processing new %s device"),
+		device_type_display_name(dev->device->type));
 
 	/* create our context */
 	ctx = device_handler_discover_context_create(handler, dev);
@@ -633,8 +1067,9 @@ int device_handler_discover(struct device_handler *handler,
 	/* add discovered stuff to the handler */
 	device_handler_discover_context_commit(handler, ctx);
 
+	process_boot_option_queue(handler);
 out:
-	talloc_free(ctx);
+	talloc_unlink(handler, ctx);
 
 	return 0;
 }
@@ -645,38 +1080,26 @@ int device_handler_dhcp(struct device_handler *handler,
 {
 	struct discover_context *ctx;
 
+	device_handler_status_dev_info(handler, dev,
+			_("Processing DHCP lease response (ip: %s)"),
+			event_get_param(event, "ip"));
+
+	pending_network_jobs_start();
+
 	/* create our context */
 	ctx = device_handler_discover_context_create(handler, dev);
+	talloc_steal(ctx, event);
 	ctx->event = event;
 
 	iterate_parsers(ctx);
 
 	device_handler_discover_context_commit(handler, ctx);
 
-	talloc_free(ctx);
+	talloc_unlink(handler, ctx);
 
 	return 0;
 }
 
-/* incoming conf event */
-int device_handler_conf(struct device_handler *handler,
-		struct discover_device *dev, struct pb_url *url)
-{
-        struct discover_context *ctx;
-
-        /* create our context */
-        ctx = device_handler_discover_context_create(handler, dev);
-        ctx->conf_url = url;
-
-        iterate_parsers(ctx);
-
-        device_handler_discover_context_commit(handler, ctx);
-
-        talloc_free(ctx);
-
-        return 0;
-}
-
 static struct discover_boot_option *find_boot_option_by_id(
 		struct device_handler *handler, const char *id)
 {
@@ -704,15 +1127,16 @@ void device_handler_boot(struct device_handler *handler,
 
 	if (handler->pending_boot)
 		boot_cancel(handler->pending_boot);
+
+	platform_pre_boot();
+
 	handler->pending_boot = boot(handler, opt, cmd, handler->dry_run,
-			boot_status, handler);
+			device_handler_boot_status_cb, handler);
 	handler->pending_boot_is_default = false;
 }
 
 void device_handler_cancel_default(struct device_handler *handler)
 {
-	struct boot_status status;
-
 	if (handler->timeout_waiter)
 		waiter_remove(handler->timeout_waiter);
 
@@ -733,30 +1157,345 @@ void device_handler_cancel_default(struct device_handler *handler)
 
 	handler->default_boot_option = NULL;
 
-	status.type = BOOT_STATUS_INFO;
-	status.progress = -1;
-	status.detail = NULL;
-	status.message = "Default boot cancelled";
-
-	discover_server_notify_boot_status(handler->server, &status);
+	device_handler_status_info(handler, _("Default boot cancelled"));
 }
 
 void device_handler_update_config(struct device_handler *handler,
 		struct config *config)
 {
-	config_set(config);
+	int rc;
+
+	rc = config_set(config);
+	if (rc)
+		return;
+
 	discover_server_notify_config(handler->server, config);
+	device_handler_update_lang(config->lang);
+	device_handler_reinit(handler);
+}
+
+static char *device_from_addr(void *ctx, struct pb_url *url)
+{
+	char *ipaddr, *buf, *tok, *dev = NULL;
+	const char *delim = " ";
+	struct sockaddr_in *ip;
+	struct sockaddr_in si;
+	struct addrinfo *res;
+	struct process *p;
+	int rc;
+
+	/* Note: IPv4 only */
+	rc = inet_pton(AF_INET, url->host, &(si.sin_addr));
+	if (rc > 0) {
+		ipaddr = url->host;
+	} else {
+		/* need to turn hostname into a valid IP */
+		rc = getaddrinfo(url->host, NULL, NULL, &res);
+		if (rc) {
+			pb_debug("%s: Invalid URL\n",__func__);
+			return NULL;
+		}
+		ipaddr = talloc_array(ctx,char,INET_ADDRSTRLEN);
+		ip = (struct sockaddr_in *) res->ai_addr;
+		inet_ntop(AF_INET, &(ip->sin_addr), ipaddr, INET_ADDRSTRLEN);
+		freeaddrinfo(res);
+	}
+
+	const char *argv[] = {
+		pb_system_apps.ip,
+		"route", "show", "to", "match",
+		ipaddr,
+		NULL
+	};
+
+	p = process_create(ctx);
+
+	p->path = pb_system_apps.ip;
+	p->argv = argv;
+	p->keep_stdout = true;
+
+	rc = process_run_sync(p);
+
+	if (rc || p->exit_status) {
+		/* ip has complained for some reason; most likely
+		 * there is no route to the host - bail out */
+		pb_debug("%s: `ip` returns non-zero exit status\n", __func__);
+		pb_debug("ip buf: %s\n", p->stdout_buf);
+		process_release(p);
+		return NULL;
+	}
+
+	buf = p->stdout_buf;
+	/* If a route is found, ip-route output will be of the form
+	 * "... dev DEVNAME ... " */
+	tok = strtok(buf, delim);
+	while (tok) {
+		if (!strcmp(tok, "dev")) {
+			tok = strtok(NULL, delim);
+			dev = talloc_strdup(ctx, tok);
+			break;
+		}
+		tok = strtok(NULL, delim);
+	}
+
+	process_release(p);
+	if (dev)
+		pb_debug("%s: Found interface '%s'\n", __func__,dev);
+	return dev;
+}
+
+static void process_url_cb(struct load_url_result *result, void *data)
+{
+	struct device_handler *handler;
+	struct discover_context *ctx;
+	struct discover_device *dev;
+	struct event *event = data;
+	const char *mac;
+
+	if (result->status != LOAD_OK) {
+		pb_log("%s: Load failed for %s\n", __func__, result->url->full);
+		return;
+	}
+
+	if (!event)
+		return;
+
+	handler = talloc_parent(event);
+	if (!handler)
+		return;
+
+	event->device = device_from_addr(event, result->url);
+	if (!event->device) {
+		pb_log("Downloaded a file but can't find its interface - pretending it was local\n");
+		event->device = talloc_asprintf(event, "local");
+	}
+
+	mac = event_get_param(event, "mac");
+	char *url = talloc_asprintf(event, "file://%s", result->local);
+	event_set_param(event, "pxeconffile", url);
+
+	dev = discover_device_create(handler, mac, event->device);
+	ctx = device_handler_discover_context_create(handler, dev);
+	talloc_steal(ctx, event);
+	ctx->event = event;
+
+	iterate_parsers(ctx);
+
+	device_handler_discover_context_commit(handler, ctx);
+
+	talloc_unlink(handler, ctx);
+}
+
+void device_handler_process_url(struct device_handler *handler,
+		const char *url, const char *mac, const char *ip)
+{
+	struct discover_context *ctx;
+	struct discover_device *dev;
+	bool allow_async = false;
+	struct pb_url *pb_url;
+	struct event *event;
+
+	event = talloc_zero(handler, struct event);
+	event->type = EVENT_TYPE_USER;
+	event->action = EVENT_ACTION_URL;
+
+	pb_url = pb_url_parse(event, url);
+	if (!pb_url || (pb_url->scheme != pb_url_file && !pb_url->host)) {
+		device_handler_status_err(handler, _("Invalid config URL!"));
+		talloc_free(event);
+		return;
+	}
+
+	if (url[strlen(url) - 1] == '/') {
+		event_set_param(event, "pxepathprefix", url);
+		event_set_param(event, "mac", mac);
+		event_set_param(event, "ip", ip);
+		event->device = device_from_addr(event, pb_url);
+		if (!event->device) {
+			device_handler_status_err(handler,
+					_("Unable to route to host %s"),
+					pb_url->host);
+			talloc_free(event);
+			return;
+		}
+	} else {
+		event_set_param(event, "pxeconffile", url);
+		allow_async = true;
+	}
+
+	if (pb_url->scheme == pb_url_file)
+		event->device = talloc_asprintf(event, "local");
+	else if (allow_async) {
+		/* If file is remote load asynchronously before passing to
+		 * parser. This allows us to wait for network to be available */
+		if (!load_url_async(handler, pb_url, process_url_cb, event,
+					NULL, handler)) {
+			pb_log("Failed to load url %s\n", pb_url->full);
+			device_handler_status_err(handler, _("Failed to load URL!"));
+			talloc_free(event);
+		}
+		return;
+	}
+
+	/* If path is local we can parse straight away */
+
+	dev = discover_device_create(handler, mac, event->device);
+	if (pb_url->scheme == pb_url_file)
+		dev->device->type = DEVICE_TYPE_ANY;
+	ctx = device_handler_discover_context_create(handler, dev);
+	talloc_steal(ctx, event);
+	ctx->event = event;
+
+	iterate_parsers(ctx);
+
+	device_handler_discover_context_commit(handler, ctx);
+
+	talloc_unlink(handler, ctx);
 }
 
 #ifndef PETITBOOT_TEST
+
+/**
+ * context_commit - Commit a temporary discovery context to the handler,
+ * and notify the clients about any new options / devices
+ */
+void device_handler_discover_context_commit(struct device_handler *handler,
+		struct discover_context *ctx)
+{
+	struct discover_device *dev = ctx->device;
+	struct discover_boot_option *opt, *tmp;
+
+	if (!device_lookup_by_uuid(handler, dev->uuid))
+		device_handler_add_device(handler, dev);
+
+	/* move boot options from the context to the device */
+	list_for_each_entry_safe(&ctx->boot_options, opt, tmp, list) {
+		list_remove(&opt->list);
+
+		/* All boot options need at least a kernel image */
+		if (!opt->boot_image || !opt->boot_image->url) {
+			pb_log("boot option %s is missing boot image, ignoring\n",
+				opt->option->id);
+			talloc_free(opt);
+			continue;
+		}
+
+		if (boot_option_resolve(opt, handler)) {
+			pb_log("boot option %s is resolved, "
+					"sending to clients\n",
+					opt->option->id);
+			list_add_tail(&dev->boot_options, &opt->list);
+			talloc_steal(dev, opt);
+			boot_option_finalise(handler, opt);
+			notify_boot_option(handler, opt);
+		} else {
+			if (!opt->source->resolve_resource) {
+				pb_log("parser %s gave us an unresolved "
+					"resource (%s), but no way to "
+					"resolve it\n",
+					opt->source->name, opt->option->id);
+				talloc_free(opt);
+			} else {
+				pb_log("boot option %s is unresolved, "
+						"adding to queue\n",
+						opt->option->id);
+				list_add(&handler->unresolved_boot_options,
+						&opt->list);
+				talloc_steal(handler, opt);
+			}
+		}
+	}
+}
+
+static void device_handler_update_lang(const char *lang)
+{
+	const char *cur_lang;
+
+	if (!lang)
+		return;
+
+	cur_lang = setlocale(LC_ALL, NULL);
+	if (cur_lang && !strcmp(cur_lang, lang))
+		return;
+
+	setlocale(LC_ALL, lang);
+}
+
+static int device_handler_init_sources(struct device_handler *handler)
+{
+	/* init our device sources: udev, network and user events */
+	handler->udev = udev_init(handler, handler->waitset);
+	if (!handler->udev)
+		return -1;
+
+	handler->network = network_init(handler, handler->waitset,
+			handler->dry_run);
+	if (!handler->network)
+		return -1;
+
+	handler->user_event = user_event_init(handler, handler->waitset);
+	if (!handler->user_event)
+		return -1;
+
+	return 0;
+}
+
+static void device_handler_reinit_sources(struct device_handler *handler)
+{
+	/* if we haven't initialised sources previously (becuase we started in
+	 * safe mode), then init once here. */
+	if (!(handler->udev || handler->network || handler->user_event)) {
+		device_handler_init_sources(handler);
+		return;
+	}
+
+	system_info_reinit();
+
+	udev_reinit(handler->udev);
+
+	network_shutdown(handler->network);
+	handler->network = network_init(handler, handler->waitset,
+			handler->dry_run);
+}
+
+static inline const char *get_device_path(struct discover_device *dev)
+{
+	return dev->ramdisk ? dev->ramdisk->snapshot : dev->device_path;
+}
+
+static char *check_subvols(struct discover_device *dev)
+{
+	const char *fstype = discover_device_get_param(dev, "ID_FS_TYPE");
+	struct stat sb;
+	char *path;
+	int rc;
+
+	if (strncmp(fstype, "btrfs", strlen("btrfs")))
+		return dev->mount_path;
+
+	/* On btrfs a device's root may be under a subvolume path */
+	path = join_paths(dev, dev->mount_path, "@");
+	rc = stat(path, &sb);
+	if (!rc && S_ISDIR(sb.st_mode)) {
+		pb_debug("Using '%s' for btrfs root path\n", path);
+		return path;
+	}
+
+	talloc_free(path);
+	return dev->mount_path;
+}
+
 static bool check_existing_mount(struct discover_device *dev)
 {
 	struct stat devstat, mntstat;
+	const char *device_path;
 	struct mntent *mnt;
 	FILE *fp;
 	int rc;
 
-	rc = stat(dev->device_path, &devstat);
+	device_path = get_device_path(dev);
+
+	rc = stat(device_path, &devstat);
 	if (rc) {
 		pb_debug("%s: stat failed: %s\n", __func__, strerror(errno));
 		return false;
@@ -787,6 +1526,7 @@ static bool check_existing_mount(struct discover_device *dev)
 
 		if (mntstat.st_rdev == devstat.st_rdev) {
 			dev->mount_path = talloc_strdup(dev, mnt->mnt_dir);
+			dev->root_path = check_subvols(dev);
 			dev->mounted_rw = !!hasmntopt(mnt, "rw");
 			dev->mounted = true;
 			dev->unmount = false;
@@ -804,8 +1544,55 @@ static bool check_existing_mount(struct discover_device *dev)
 	return mnt != NULL;
 }
 
+/*
+ * Attempt to mount a filesystem safely, while handling certain filesytem-
+ * specific options
+ */
+static int try_mount(const char *device_path, const char *mount_path,
+			     const char *fstype, unsigned long flags,
+			     bool have_snapshot)
+{
+	const char *fs, *safe_opts;
+	int rc;
+
+	/* Mount ext3 as ext4 instead so 'norecovery' can be used */
+	if (strncmp(fstype, "ext3", strlen("ext3")) == 0) {
+		pb_debug("Mounting ext3 filesystem as ext4\n");
+		fs = "ext4";
+	} else
+		fs = fstype;
+
+	if (strncmp(fs, "xfs", strlen("xfs")) == 0 ||
+	    strncmp(fs, "ext4", strlen("ext4")) == 0)
+		safe_opts = "norecovery";
+	else
+		safe_opts = NULL;
+
+	errno = 0;
+	/* If no snapshot is available don't attempt recovery */
+	if (!have_snapshot)
+		return mount(device_path, mount_path, fs, flags, safe_opts);
+
+	rc = mount(device_path, mount_path, fs, flags, NULL);
+
+	if (!rc)
+		return rc;
+
+	/* Mounting failed; some filesystems will fail to mount if a recovery
+	 * journal exists (eg. cross-endian XFS), so try again with norecovery
+	 * where that option is available.
+	 * If mounting read-write just return the error as norecovery is not a
+	 * valid option */
+	if ((flags & MS_RDONLY) != MS_RDONLY || !safe_opts)
+		return rc;
+
+	errno = 0;
+	return mount(device_path, mount_path, fs, flags, safe_opts);
+}
+
 static int mount_device(struct discover_device *dev)
 {
+	const char *fstype, *device_path;
 	int rc;
 
 	if (!dev->device_path)
@@ -817,6 +1604,10 @@ static int mount_device(struct discover_device *dev)
 	if (check_existing_mount(dev))
 		return 0;
 
+	fstype = discover_device_get_param(dev, "ID_FS_TYPE");
+	if (!fstype)
+		return 0;
+
 	dev->mount_path = join_paths(dev, mount_base(),
 					dev->device_path);
 
@@ -826,26 +1617,25 @@ static int mount_device(struct discover_device *dev)
 		goto err_free;
 	}
 
-	rc = process_run_simple(dev, pb_system_apps.mount,
-			dev->device_path, dev->mount_path,
-			"-o", "ro", NULL);
+	device_path = get_device_path(dev);
+
+	pb_log("mounting device %s read-only\n", dev->device_path);
+	rc = try_mount(device_path, dev->mount_path, fstype,
+		       MS_RDONLY | MS_SILENT, dev->ramdisk);
+
 	if (!rc) {
 		dev->mounted = true;
 		dev->mounted_rw = false;
 		dev->unmount = true;
+		dev->root_path = check_subvols(dev);
 		return 0;
 	}
 
-	/* Retry mount without ro option. */
-	rc = process_run_simple(dev, pb_system_apps.mount,
-			dev->device_path, dev->mount_path, NULL);
+	pb_log("couldn't mount device %s: mount failed: %s\n",
+			device_path, strerror(errno));
 
-	if (!rc) {
-		dev->mounted = true;
-		dev->mounted_rw = true;
-		dev->unmount = true;
-		return 0;
-	}
+	/* If mount fails clean up any snapshot */
+	devmapper_destroy_snapshot(dev);
 
 	pb_rmdir_recursive(mount_base(), dev->mount_path);
 err_free:
@@ -856,61 +1646,174 @@ err_free:
 
 static int umount_device(struct discover_device *dev)
 {
-	int status;
+	const char *device_path;
+	int rc;
 
 	if (!dev->mounted || !dev->unmount)
 		return 0;
 
-	status = process_run_simple(dev, pb_system_apps.umount,
-			dev->mount_path, NULL);
+	device_path = get_device_path(dev);
 
-	if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
+	pb_log("unmounting device %s\n", device_path);
+	rc = umount(dev->mount_path);
+	if (rc)
 		return -1;
 
 	dev->mounted = false;
+	devmapper_destroy_snapshot(dev);
 
 	pb_rmdir_recursive(mount_base(), dev->mount_path);
 
 	talloc_free(dev->mount_path);
 	dev->mount_path = NULL;
+	dev->root_path = NULL;
 
 	return 0;
 }
 
 int device_request_write(struct discover_device *dev, bool *release)
 {
+	const char *fstype, *device_path;
+	const struct config *config;
 	int rc;
 
 	*release = false;
 
+	config = config_get();
+	if (!config->allow_writes)
+		return -1;
+
 	if (!dev->mounted)
 		return -1;
 
 	if (dev->mounted_rw)
 		return 0;
 
-	rc = process_run_simple(dev, pb_system_apps.mount, dev->mount_path,
-			"-o", "remount,rw", NULL);
-	if (rc)
+	fstype = discover_device_get_param(dev, "ID_FS_TYPE");
+
+	device_path = get_device_path(dev);
+
+	pb_log("remounting device %s read-write\n", device_path);
+
+	rc = umount(dev->mount_path);
+	if (rc) {
+		pb_log("Failed to unmount %s: %s\n",
+		       dev->mount_path, strerror(errno));
 		return -1;
+	}
+
+	rc = try_mount(device_path, dev->mount_path, fstype,
+		       MS_SILENT, dev->ramdisk);
+	if (rc)
+		goto mount_ro;
 
 	dev->mounted_rw = true;
 	*release = true;
 	return 0;
+
+mount_ro:
+	pb_log("Unable to remount device %s read-write: %s\n",
+	       device_path, strerror(errno));
+	rc = try_mount(device_path, dev->mount_path, fstype,
+		       MS_RDONLY | MS_SILENT, dev->ramdisk);
+	if (rc)
+		pb_log("Unable to recover mount for %s: %s\n",
+		       device_path, strerror(errno));
+	return -1;
 }
 
 void device_release_write(struct discover_device *dev, bool release)
 {
+	const char *fstype, *device_path;
+
 	if (!release)
 		return;
 
-	process_run_simple(dev, pb_system_apps.mount, dev->mount_path,
-			"-o", "remount,ro", NULL);
-	dev->mounted_rw = false;
+	device_path = get_device_path(dev);
+
+	fstype = discover_device_get_param(dev, "ID_FS_TYPE");
+
+	pb_log("remounting device %s read-only\n", device_path);
+
+	if (umount(dev->mount_path)) {
+		pb_log("Failed to unmount %s\n", dev->mount_path);
+		return;
+	}
+	dev->mounted_rw = dev->mounted = false;
+
+	if (dev->ramdisk) {
+		devmapper_merge_snapshot(dev);
+		/* device_path becomes stale after merge */
+		device_path = get_device_path(dev);
+	}
+
+	if (try_mount(device_path, dev->mount_path, fstype,
+		       MS_RDONLY | MS_SILENT, dev->ramdisk))
+		pb_log("Failed to remount %s read-only: %s\n",
+		       device_path, strerror(errno));
+	else
+		dev->mounted = true;
+}
+
+void device_sync_snapshots(struct device_handler *handler, const char *device)
+{
+	struct discover_device *dev = NULL;
+	unsigned int i;
+
+	if (device) {
+		/* Find matching device and sync */
+		dev = device_lookup_by_name(handler, device);
+		if (!dev) {
+			pb_log("%s: device name '%s' unrecognised\n",
+				__func__, device);
+			return;
+		}
+		if (dev->ramdisk)
+			device_release_write(dev, true);
+		else
+			pb_log("%s has no snapshot to merge, skipping\n",
+				dev->device->id);
+		return;
+	}
+
+	/* Otherwise sync all relevant devices */
+	for (i = 0; i < handler->n_devices; i++) {
+		dev = handler->devices[i];
+		if (dev->device->type != DEVICE_TYPE_DISK &&
+			dev->device->type != DEVICE_TYPE_USB)
+			continue;
+		if (dev->ramdisk)
+			device_release_write(dev, true);
+		else
+			pb_log("%s has no snapshot to merge, skipping\n",
+				dev->device->id);
+	}
 }
 
 #else
 
+void device_handler_discover_context_commit(
+		struct device_handler *handler __attribute__((unused)),
+		struct discover_context *ctx __attribute__((unused)))
+{
+	pb_log("%s stubbed out for test cases\n", __func__);
+}
+
+static void device_handler_update_lang(const char *lang __attribute__((unused)))
+{
+}
+
+static int device_handler_init_sources(
+		struct device_handler *handler __attribute__((unused)))
+{
+	return 0;
+}
+
+static void device_handler_reinit_sources(
+		struct device_handler *handler __attribute__((unused)))
+{
+}
+
 static int umount_device(struct discover_device *dev __attribute__((unused)))
 {
 	return 0;
@@ -934,5 +1837,10 @@ void device_release_write(struct discover_device *dev __attribute__((unused)),
 {
 }
 
-#endif
+void device_sync_snapshots(
+		struct device_handler *handler __attribute__((unused)),
+		const char *device __attribute__((unused)))
+{
+}
 
+#endif