Make state snapshots compatible with SD cards.

This patch introduces a check such that only drives exporting a
snapshot creation function are considered for storing snapshots.
SD cards are mounted with a raw file system, which does not
support snapshots. Since the SD card is now skipped, the actual
snapshot image can be safely mounted on hdb rather than hda.

The contents of the SD card itself are included in the snapshot
however, since they are accessed with the NAND driver (which
saves the contents of the underlying files).

Change-Id: I4816b6e54e227aca356389c15ce9f5c1282d2464

1 files changed, 6 insertions, 22 deletions

diff --git a/savevm.c b/savevm.c
index 8f0d8f1..ee90805 100644
--- a/savevm.c
+++ b/savevm.c
@@ -907,8 +907,8 @@ int qemu_savevm_state_complete(QEMUFile *f)
     for(se = first_se; se != NULL; se = se->next) {
         int len;
 
-	if (se->save_state == NULL)
-	    continue;
+        if (se->save_state == NULL)
+            continue;
 
         /* Section type */
         qemu_put_byte(f, QEMU_VM_SECTION_FULL);
@@ -1122,22 +1122,6 @@ out:
     return ret;
 }
 
-/* device can contain snapshots */
-static int bdrv_can_snapshot(BlockDriverState *bs)
-{
-    return (bs &&
-            !bdrv_is_removable(bs) &&
-            !bdrv_is_read_only(bs));
-}
-
-/* device must be snapshots in order to have a reliable snapshot */
-static int bdrv_has_snapshot(BlockDriverState *bs)
-{
-    return (bs &&
-            !bdrv_is_removable(bs) &&
-            !bdrv_is_read_only(bs));
-}
-
 static BlockDriverState *get_bs_snapshots(void)
 {
     BlockDriverState *bs;
@@ -1257,7 +1241,7 @@ void do_savevm(Monitor *mon, const char *name)
 
     for(i = 0; i < nb_drives; i++) {
         bs1 = drives_table[i].bdrv;
-        if (bdrv_has_snapshot(bs1)) {
+        if (bdrv_can_snapshot(bs1)) {
             if (must_delete) {
                 ret = bdrv_snapshot_delete(bs1, old_sn->id_str);
                 if (ret < 0) {
@@ -1304,7 +1288,7 @@ void do_loadvm(Monitor *mon, const char *name)
 
     for(i = 0; i <= nb_drives; i++) {
         bs1 = drives_table[i].bdrv;
-        if (bdrv_has_snapshot(bs1)) {
+        if (bdrv_can_snapshot(bs1)) {
             ret = bdrv_snapshot_goto(bs1, name);
             if (ret < 0) {
                 if (bs != bs1)
@@ -1372,7 +1356,7 @@ void do_delvm(Monitor *mon, const char *name)
 
     for(i = 0; i <= nb_drives; i++) {
         bs1 = drives_table[i].bdrv;
-        if (bdrv_has_snapshot(bs1)) {
+        if (bdrv_can_snapshot(bs1)) {
             ret = bdrv_snapshot_delete(bs1, name);
             if (ret < 0) {
                 if (ret == -ENOTSUP)
@@ -1402,7 +1386,7 @@ void do_info_snapshots(Monitor *mon)
     monitor_printf(mon, "Snapshot devices:");
     for(i = 0; i <= nb_drives; i++) {
         bs1 = drives_table[i].bdrv;
-        if (bdrv_has_snapshot(bs1)) {
+        if (bdrv_can_snapshot(bs1)) {
             if (bs == bs1)
                 monitor_printf(mon, " %s", bdrv_get_device_name(bs1));
         }