Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-3.1-pull-request...

[qemu.git] / block / snapshot.c

diff --git a/block/snapshot.c b/block/snapshot.c
index be0743abac874b21a10e8375e6ababc94084276a..3218a542df833170b4da85f91c726131651d6894 100644 (file)
--- a/block/snapshot.c
+++ b/block/snapshot.c
@@ -25,9 +25,12 @@
 #include "qemu/osdep.h"
 #include "block/snapshot.h"
 #include "block/block_int.h"
+#include "block/qdict.h"
 #include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qerror.h"
 #include "qapi/qmp/qstring.h"
+#include "qemu/option.h"
 
 QemuOptsList internal_snapshot_opts = {
     .name = "snapshot",
@@ -177,56 +180,59 @@ int bdrv_snapshot_create(BlockDriverState *bs,
 }
 
 int bdrv_snapshot_goto(BlockDriverState *bs,
-                       const char *snapshot_id)
+                       const char *snapshot_id,
+                       Error **errp)
 {
     BlockDriver *drv = bs->drv;
     int ret, open_ret;
-    int64_t len;
 
     if (!drv) {
+        error_setg(errp, "Block driver is closed");
         return -ENOMEDIUM;
     }
 
-    len = bdrv_getlength(bs);
-    if (len < 0) {
-        return len;
+    if (!QLIST_EMPTY(&bs->dirty_bitmaps)) {
+        error_setg(errp, "Device has active dirty bitmaps");
+        return -EBUSY;
     }
-    /* We should set all bits in all enabled dirty bitmaps, because dirty
-     * bitmaps reflect active state of disk and snapshot switch operation
-     * actually dirties active state.
-     * TODO: It may make sense not to set all bits but analyze block status of
-     * current state and destination snapshot and do not set bits corresponding
-     * to both-zero or both-unallocated areas. */
-    bdrv_set_dirty(bs, 0, len);
 
     if (drv->bdrv_snapshot_goto) {
-        return drv->bdrv_snapshot_goto(bs, snapshot_id);
+        ret = drv->bdrv_snapshot_goto(bs, snapshot_id);
+        if (ret < 0) {
+            error_setg_errno(errp, -ret, "Failed to load snapshot");
+        }
+        return ret;
     }
 
     if (bs->file) {
         BlockDriverState *file;
         QDict *options = qdict_clone_shallow(bs->options);
         QDict *file_options;
+        Error *local_err = NULL;
 
         file = bs->file->bs;
         /* Prevent it from getting deleted when detached from bs */
         bdrv_ref(file);
 
         qdict_extract_subqdict(options, &file_options, "file.");
-        QDECREF(file_options);
+        qobject_unref(file_options);
         qdict_put_str(options, "file", bdrv_get_node_name(file));
 
-        drv->bdrv_close(bs);
+        if (drv->bdrv_close) {
+            drv->bdrv_close(bs);
+        }
         bdrv_unref_child(bs, bs->file);
         bs->file = NULL;
 
-        ret = bdrv_snapshot_goto(file, snapshot_id);
-        open_ret = drv->bdrv_open(bs, options, bs->open_flags, NULL);
-        QDECREF(options);
+        ret = bdrv_snapshot_goto(file, snapshot_id, errp);
+        open_ret = drv->bdrv_open(bs, options, bs->open_flags, &local_err);
+        qobject_unref(options);
         if (open_ret < 0) {
             bdrv_unref(file);
             bs->drv = NULL;
-            return open_ret;
+            /* A bdrv_snapshot_goto() error takes precedence */
+            error_propagate(errp, local_err);
+            return ret < 0 ? ret : open_ret;
         }
 
         assert(bs->file->bs == file);
@@ -234,6 +240,7 @@ int bdrv_snapshot_goto(BlockDriverState *bs,
         return ret;
     }
 
+    error_setg(errp, "Block driver does not support snapshots");
     return -ENOTSUP;
 }
 
@@ -456,9 +463,10 @@ fail:
 }
 
 
-int bdrv_all_goto_snapshot(const char *name, BlockDriverState **first_bad_bs)
+int bdrv_all_goto_snapshot(const char *name, BlockDriverState **first_bad_bs,
+                           Error **errp)
 {
-    int err = 0;
+    int ret = 0;
     BlockDriverState *bs;
     BdrvNextIterator it;
 
@@ -467,10 +475,10 @@ int bdrv_all_goto_snapshot(const char *name, BlockDriverState **first_bad_bs)
 
         aio_context_acquire(ctx);
         if (bdrv_can_snapshot(bs)) {
-            err = bdrv_snapshot_goto(bs, name);
+            ret = bdrv_snapshot_goto(bs, name, errp);
         }
         aio_context_release(ctx);
-        if (err < 0) {
+        if (ret < 0) {
             bdrv_next_cleanup(&it);
             goto fail;
         }
@@ -478,7 +486,7 @@ int bdrv_all_goto_snapshot(const char *name, BlockDriverState **first_bad_bs)
 
 fail:
     *first_bad_bs = bs;
-    return err;
+    return ret;
 }
 
 int bdrv_all_find_snapshot(const char *name, BlockDriverState **first_bad_bs)