discover: Add disable param for dm-snapshots

Add a debug-style nvram parameter to disallow the use of device-mapper
snapshots.

Signed-off-by: Samuel Mendoza-Jonas <sam.mj@au1.ibm.com>

3 files changed, 13 insertions, 0 deletions

diff --git a/discover/devmapper.c b/discover/devmapper.c
index 1fd1215..e2ef0b5 100644
--- a/discover/devmapper.c
+++ b/discover/devmapper.c
@@ -6,6 +6,7 @@
 
 #include "libdevmapper.h"
 #include "devmapper.h"
+#include "platform.h"
 
 #define MERGE_INTERVAL_US	200000
 
@@ -320,6 +321,9 @@ int devmapper_init_snapshot(struct device_handler *handler,
 {
 	struct ramdisk_device *ramdisk;
 
+	if (config_get()->disable_snapshots)
+		return 0;
+
 	ramdisk = device_handler_get_ramdisk(handler);
 	if (!ramdisk) {
 		pb_log("No ramdisk available for snapshot %s\n",
diff --git a/discover/platform-powerpc.c b/discover/platform-powerpc.c
index fc96305..d45cced 100644
--- a/discover/platform-powerpc.c
+++ b/discover/platform-powerpc.c
@@ -54,6 +54,7 @@ static const char *known_params[] = {
 	"petitboot,language",
 	"petitboot,debug?",
 	"petitboot,write?",
+	"petitboot,snapshots?",
 	NULL,
 };
 
@@ -553,6 +554,10 @@ static void populate_config(struct platform_powerpc *platform,
 	val = get_param(platform, "petitboot,write?");
 	if (val)
 		config->allow_writes = !strcmp(val, "true");
+
+	val = get_param(platform, "petitboot,snapshots?");
+	if (val)
+		config->disable_snapshots = !strcmp(val, "false");
 }
 
 static char *iface_config_str(void *ctx, struct interface_config *config)
diff --git a/discover/platform.c b/discover/platform.c
index b1d0f19..a6bd74c 100644
--- a/discover/platform.c
+++ b/discover/platform.c
@@ -35,6 +35,9 @@ static void dump_config(struct config *config)
 	if (config->safe_mode)
 		pb_log(" safe mode: active\n");
 
+	if (config->disable_snapshots)
+		pb_log(" dm-snapshots disabled\n");
+
 	for (i = 0; i < config->network.n_interfaces; i++) {
 		struct interface_config *ifconf =
 			config->network.interfaces[i];
@@ -109,6 +112,7 @@ void config_set_defaults(struct config *config)
 	config->safe_mode = false;
 	config->lang = NULL;
 	config->allow_writes = true;
+	config->disable_snapshots = false;
 
 	config->n_autoboot_opts = 2;
 	config->autoboot_opts = talloc_array(config, struct autoboot_option,