xen/snapshot-ioemu-save.patch

Index: xen-3.3.0-testing/tools/ioemu/vl.c
===================================================================
--- xen-3.3.0-testing.orig/tools/ioemu/vl.c
+++ xen-3.3.0-testing/tools/ioemu/vl.c
@@ -108,6 +108,8 @@
 
 #include "exec-all.h"
 
+#include "block_int.h"
+
 #define DEFAULT_NETWORK_SCRIPT "/etc/xen/qemu-ifup"
 #ifdef _BSD
 #define DEFAULT_BRIDGE "bridge0"
@@ -5155,6 +5157,83 @@ void do_loadvm(const char *name)
     if (saved_vm_running)
         vm_start();
 }
+
+int save_disk_snapshots(const char* name)
+{
+    BlockDriverState *bs;
+    QEMUSnapshotInfo sn, old_sn;
+    struct timeval tv;
+    int saved_vm_running;
+    int can_snapshot;
+    int i;
+    int ret = 0;
+
+    saved_vm_running = vm_running;
+    vm_stop(0);
+
+    qemu_aio_flush();
+
+    /* Ensure that all images support snapshots or are read-only */
+    for(i = 0; i < MAX_DISKS; i++) {
+        bs = bs_table[i];
+
+        if (!bs || !bs->drv)
+            continue;
+
+        can_snapshot = bs->drv->bdrv_snapshot_create && bdrv_can_snapshot(bs);
+        if (!bdrv_is_read_only(bs) && !can_snapshot) {
+            fprintf(stderr, "Error: bdrv %s (%s) doesn't support snapshots\n",
+                bdrv_get_device_name(bs), bs->drv->format_name);
+            ret = -ENOTSUP;
+            goto the_end;
+        }
+    }
+
+    /* fill auxiliary fields */
+    memset(&sn, 0, sizeof(sn));
+    gettimeofday(&tv, NULL);
+    sn.date_sec = tv.tv_sec;
+    sn.date_nsec = tv.tv_usec * 1000;
+    sn.vm_clock_nsec = qemu_get_clock(vm_clock);
+    pstrcpy(sn.name, sizeof(sn.name), name);
+
+    for(i = 0; i < MAX_DISKS; i++) {
+        bs = bs_table[i];
+
+        /* No snapshots on read-only images */
+        if (!bs || !bs->drv || bdrv_is_read_only(bs))
+            continue;
+
+        /* Delete old snapshot of the same name */
+        if (bdrv_snapshot_find(bs, &old_sn, name) >= 0) {
+            ret = bdrv_snapshot_delete(bs, old_sn.id_str);
+            if (ret < 0) {
+                fprintf(stderr, "Error while deleting snapshot on '%s'\n",
+                            bdrv_get_device_name(bs));
+            }
+        }
+
+        /* Create the snapshot */
+        fprintf(stderr, "Creating snapshot on '%s' (%s)\n",
+            bdrv_get_device_name(bs), bs->drv->format_name);
+        ret = bdrv_snapshot_create(bs, &sn);
+        if (ret < 0) {
+            fprintf(stderr, "Error while creating snapshot on '%s': %d (%s)\n",
+                        bdrv_get_device_name(bs), ret, strerror(-ret));
+            goto the_end;
+        }
+    }
+
+    fprintf(stderr, "Created all snapshots\n");
+
+the_end:
+    if (saved_vm_running)
+        vm_start();
+
+    return ret;
+}
+
+
 #else 
 void do_savevm(const char *name)
 {
Index: xen-3.3.0-testing/tools/ioemu/target-i386-dm/helper2.c
===================================================================
--- xen-3.3.0-testing.orig/tools/ioemu/target-i386-dm/helper2.c
+++ xen-3.3.0-testing/tools/ioemu/target-i386-dm/helper2.c
@@ -92,6 +92,9 @@ int send_vcpu = 0;
 #define NR_CPUS 32
 evtchn_port_t ioreq_local_port[NR_CPUS];
 
+/** Name of the snapshot which should be saved */
+char* snapshot_name;
+
 CPUX86State *cpu_x86_init(void)
 {
     CPUX86State *env;
@@ -556,9 +559,24 @@ int main_loop(void)
         main_loop_wait(1); /* For the select() on events */
 
         /* Save the device state */
-        asprintf(&qemu_file, "/var/lib/xen/qemu-save.%d", domid);
-        do_savevm(qemu_file);
-        free(qemu_file);
+        switch (suspend_requested) {
+        case SUSPEND_SAVEVM:
+            asprintf(&qemu_file, "/var/lib/xen/qemu-save.%d", domid);
+            do_savevm(qemu_file);
+            free(qemu_file);
+            break;
+
+        case SUSPEND_SNAPSHOT:
+            // TODO Error reporting
+            if (snapshot_name != NULL) {
+                save_disk_snapshots(snapshot_name);
+                free(snapshot_name);
+                snapshot_name = NULL;
+            } else {
+                fprintf(logfile, "No snapshot name given\n");
+            }
+            break;
+        }
 
         xenstore_record_dm_state("paused");
 
Index: xen-3.3.0-testing/tools/ioemu/vl.h
===================================================================
--- xen-3.3.0-testing.orig/tools/ioemu/vl.h
+++ xen-3.3.0-testing/tools/ioemu/vl.h
@@ -59,7 +59,6 @@
 extern int qemu_ftruncate64(int, int64_t);
 #define ftruncate qemu_ftruncate64
 
-
 static inline char *realpath(const char *path, char *resolved_path)
 {
     _fullpath(resolved_path, path, _MAX_PATH);
@@ -72,6 +71,11 @@ static inline char *realpath(const char 
 #define PRIo64 "I64o"
 #endif
 
+enum {
+    SUSPEND_SAVEVM      = 1,
+    SUSPEND_SNAPSHOT    = 2
+};
+
 #ifdef QEMU_TOOL
 
 /* we use QEMU_TOOL in the command line tools which do not depend on
@@ -557,6 +561,8 @@ void do_loadvm(const char *name);
 void do_delvm(const char *name);
 void do_info_snapshots(void);
 
+int save_disk_snapshots(const char* name);
+
 /* bottom halves */
 typedef void QEMUBHFunc(void *opaque);
 
Index: xen-3.3.0-testing/tools/ioemu/xenstore.c
===================================================================
--- xen-3.3.0-testing.orig/tools/ioemu/xenstore.c
+++ xen-3.3.0-testing/tools/ioemu/xenstore.c
@@ -536,6 +536,7 @@ static void xenstore_process_dm_command_
     char *path = NULL, *command = NULL, *par = NULL;
     unsigned int len;
     extern int suspend_requested;
+    extern char* snapshot_name;
 
     if (pasprintf(&path, 
                   "/local/domain/0/device-model/%u/command", domid) == -1) {
@@ -548,7 +549,18 @@ static void xenstore_process_dm_command_
     
     if (!strncmp(command, "save", len)) {
         fprintf(logfile, "dm-command: pause and save state\n");
-        suspend_requested = 1;
+        suspend_requested = SUSPEND_SAVEVM;
+    } else if (!strncmp(command, "snapshot", len)) {
+        fprintf(logfile, "dm-command: pause and snapshot disks\n");
+        suspend_requested = SUSPEND_SNAPSHOT;
+
+        if (pasprintf(&path,
+                "/local/domain/0/device-model/%u/parameter", domid) == -1) {
+            fprintf(logfile, "out of memory reading dm command parameter\n");
+            goto out;
+        }
+
+        snapshot_name = xs_read(xsh, XBT_NULL, path, &len);
     } else if (!strncmp(command, "continue", len)) {
         fprintf(logfile, "dm-command: continue after state save\n");
         suspend_requested = 0;
Index: xen-3.3.0-testing/tools/ioemu/hw/xen_blktap.c
===================================================================
--- xen-3.3.0-testing.orig/tools/ioemu/hw/xen_blktap.c
+++ xen-3.3.0-testing/tools/ioemu/hw/xen_blktap.c
@@ -221,8 +221,12 @@ static int open_disk(struct td_state *s,
 	struct disk_id id;
 	BlockDriverState* bs;
 
+#ifndef QEMU_TOOL
+	int i;
+#endif
+
 	DPRINTF("Opening %s\n", path);
-	bs = calloc(1, sizeof(*bs));
+	bs = bdrv_new("blktap");
 
 	memset(&id, 0, sizeof(struct disk_id));
 
@@ -238,6 +242,15 @@ static int open_disk(struct td_state *s,
 
 	s->info = ((s->flags & TD_RDONLY) ? VDISK_READONLY : 0);
 
+#ifndef QEMU_TOOL
+	for (i = 0; i < MAX_DISKS + MAX_SCSI_DISKS; i++) {
+		if (bs_table[i] == NULL) {
+			bs_table[i] = bs;
+			break;
+		}
+	}
+#endif
+
 	return 0;
 }