1 files changed, 186 insertions, 27 deletions

diff --git a/discover/device-handler.c b/discover/device-handler.c
index 64095f1..4e25e07 100644
--- a/discover/device-handler.c
+++ b/discover/device-handler.c
@@ -26,6 +26,7 @@
 
 #include "device-handler.h"
 #include "discover-server.h"
+#include "devmapper.h"
 #include "user-event.h"
 #include "platform.h"
 #include "event.h"
@@ -56,6 +57,9 @@ struct device_handler {
 	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;
@@ -319,6 +323,7 @@ struct device_handler *device_handler_init(struct discover_server *server,
 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);
@@ -330,13 +335,20 @@ void device_handler_reinit(struct device_handler *handler)
 	list_init(&handler->unresolved_boot_options);
 
 	/* drop all devices */
-	for (i = 0; i < handler->n_devices; i++)
+	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);
 }
@@ -445,6 +457,7 @@ struct {
 } 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 },
 };
 
@@ -748,6 +761,95 @@ void device_handler_add_device(struct device_handler *handler,
 		network_register_device(handler->network, device);
 }
 
+void device_handler_add_ramdisk(struct device_handler *handler,
+		const char *path)
+{
+	struct ramdisk_device *dev;
+	unsigned int i;
+
+	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 {
+			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_release_ramdisk(struct discover_device *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
  * array, but has only just been initialised by the hotplug source.
  */
@@ -1123,28 +1225,46 @@ static void device_handler_reinit_sources(struct device_handler *handler)
 			handler->dry_run);
 }
 
-static const char *fs_parameters(unsigned int rw_flags, const char *fstype)
+static const char *fs_parameters(struct discover_device *dev,
+				 unsigned int rw_flags)
 {
+	const char *fstype = discover_device_get_param(dev, "ID_FS_TYPE");
+
+	/* XFS journals are not cross-endian compatible; don't try recovery
+	 * even if we have a snapshot */
+	if (!strncmp(fstype, "xfs", strlen("xfs")))
+		return "norecovery";
+
+	/* If we have a snapshot available allow touching the filesystem */
+	if (dev->ramdisk)
+		return "";
+
 	if ((rw_flags | MS_RDONLY) != MS_RDONLY)
 		return "";
 
-	/* Avoid writing back to the disk on journaled filesystems */
+	/* Avoid writes due to journal replay if we don't have a snapshot */
 	if (!strncmp(fstype, "ext4", strlen("ext4")))
 		return "norecovery";
-	if (!strncmp(fstype, "xfs", strlen("xfs")))
-		return "norecovery";
 
 	return "";
 }
 
+static inline const char *get_device_path(struct discover_device *dev)
+{
+	return dev->ramdisk ? dev->ramdisk->snapshot : dev->device_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;
@@ -1194,7 +1314,7 @@ static bool check_existing_mount(struct discover_device *dev)
 
 static int mount_device(struct discover_device *dev)
 {
-	const char *fstype;
+	const char *fstype, *device_path;
 	int rc;
 
 	if (!dev->device_path)
@@ -1226,11 +1346,13 @@ static int mount_device(struct discover_device *dev)
 		goto err_free;
 	}
 
+	device_path = get_device_path(dev);
+
 	pb_log("mounting device %s read-only\n", dev->device_path);
 	errno = 0;
-	rc = mount(dev->device_path, dev->mount_path, fstype,
+	rc = mount(device_path, dev->mount_path, fstype,
 			MS_RDONLY | MS_SILENT,
-			fs_parameters(MS_RDONLY, fstype));
+			fs_parameters(dev, MS_RDONLY));
 	if (!rc) {
 		dev->mounted = true;
 		dev->mounted_rw = false;
@@ -1239,7 +1361,10 @@ static int mount_device(struct discover_device *dev)
 	}
 
 	pb_log("couldn't mount device %s: mount failed: %s\n",
-			dev->device_path, strerror(errno));
+			device_path, strerror(errno));
+
+	/* If mount fails clean up any snapshot */
+	devmapper_destroy_snapshot(dev);
 
 	pb_rmdir_recursive(mount_base(), dev->mount_path);
 err_free:
@@ -1250,17 +1375,21 @@ err_free:
 
 static int umount_device(struct discover_device *dev)
 {
+	const char *device_path;
 	int rc;
 
 	if (!dev->mounted || !dev->unmount)
 		return 0;
 
-	pb_log("unmounting device %s\n", dev->device_path);
+	device_path = get_device_path(dev);
+
+	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);
 
@@ -1272,11 +1401,16 @@ static int umount_device(struct discover_device *dev)
 
 int device_request_write(struct discover_device *dev, bool *release)
 {
-	const char *fstype;
+	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;
 
@@ -1285,16 +1419,20 @@ int device_request_write(struct discover_device *dev, bool *release)
 
 	fstype = discover_device_get_param(dev, "ID_FS_TYPE");
 
-	pb_log("remounting device %s read-write\n", dev->device_path);
+	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\n", dev->mount_path);
+		pb_log("Failed to unmount %s: %s\n",
+		       dev->mount_path, strerror(errno));
 		return -1;
 	}
-	rc = mount(dev->device_path, dev->mount_path, fstype,
+
+	rc = mount(device_path, dev->mount_path, fstype,
 			MS_SILENT,
-			fs_parameters(MS_REMOUNT, fstype));
+			fs_parameters(dev, MS_REMOUNT));
 	if (rc)
 		goto mount_ro;
 
@@ -1303,29 +1441,50 @@ int device_request_write(struct discover_device *dev, bool *release)
 	return 0;
 
 mount_ro:
-	pb_log("Unable to remount device %s read-write\n", dev->device_path);
-	rc = mount(dev->device_path, dev->mount_path, fstype,
+	pb_log("Unable to remount device %s read-write: %s\n",
+	       device_path, strerror(errno));
+	if (mount(device_path, dev->mount_path, fstype,
 			MS_RDONLY | MS_SILENT,
-			fs_parameters(MS_RDONLY, fstype));
-	if (rc)
-		pb_log("Unable to recover mount for %s\n", dev->device_path);
+			fs_parameters(dev, MS_RDONLY)))
+		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;
+	const char *fstype, *device_path;
+	int rc = 0;
 
 	if (!release)
 		return;
 
+	device_path = get_device_path(dev);
+
 	fstype = discover_device_get_param(dev, "ID_FS_TYPE");
 
-	pb_log("remounting device %s read-only\n", dev->device_path);
-	mount(dev->device_path, dev->mount_path, "",
-			MS_REMOUNT | MS_RDONLY | MS_SILENT,
-			fs_parameters(MS_RDONLY, fstype));
-	dev->mounted_rw = false;
+	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);
+	}
+
+	mount(device_path, dev->mount_path, fstype,
+			MS_RDONLY | MS_SILENT,
+			fs_parameters(dev, MS_RDONLY));
+	if (rc)
+		pb_log("Failed to remount %s read-only: %s\n",
+		       device_path, strerror(errno));
+	else
+		dev->mounted = true;
 }
 
 #else