@@ -4647,3 +4647,22 @@ int bdrv_amend_options(BlockDriverState *bs, QEMUOptionParameter *options)
}
return bs->drv->bdrv_amend_options(bs, options);
}
+
+ExtSnapshotPerm bdrv_check_ext_snapshot(BlockDriverState *bs)
+{
+ if (bs->drv->bdrv_check_ext_snapshot) {
+ return bs->drv->bdrv_check_ext_snapshot(bs);
+ }
+
+ if (bs->file && bs->file->drv && bs->file->drv->bdrv_check_ext_snapshot) {
+ return bs->file->drv->bdrv_check_ext_snapshot(bs);
+ }
+
+ /* external snapshots are allowed by default */
+ return EXT_SNAPSHOT_ALLOWED;
+}
+
+ExtSnapshotPerm bdrv_check_ext_snapshot_forbidden(BlockDriverState *bs)
+{
+ return EXT_SNAPSHOT_FORBIDDEN;
+}
@@ -417,6 +417,8 @@ static BlockDriver bdrv_blkverify = {
.bdrv_aio_readv = blkverify_aio_readv,
.bdrv_aio_writev = blkverify_aio_writev,
.bdrv_aio_flush = blkverify_aio_flush,
+
+ .bdrv_check_ext_snapshot = bdrv_check_ext_snapshot_forbidden,
};
static void bdrv_blkverify_init(void)
@@ -1131,6 +1131,11 @@ static void external_snapshot_prepare(BlkTransactionState *common,
}
}
+ if (bdrv_check_ext_snapshot(state->old_bs) != EXT_SNAPSHOT_ALLOWED) {
+ error_set(errp, QERR_FEATURE_DISABLED, "snapshot");
+ return;
+ }
+
flags = state->old_bs->open_flags;
/* create new image w/backing file */
@@ -248,6 +248,20 @@ int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix);
int bdrv_amend_options(BlockDriverState *bs_new, QEMUOptionParameter *options);
+/* external snapshots */
+
+typedef enum {
+ EXT_SNAPSHOT_ALLOWED,
+ EXT_SNAPSHOT_FORBIDDEN,
+} ExtSnapshotPerm;
+
+/* return EXT_SNAPSHOT_ALLOWED if external snapshot is allowed
+ * return EXT_SNAPSHOT_FORBIDDEN if external snapshot is forbidden
+ */
+ExtSnapshotPerm bdrv_check_ext_snapshot(BlockDriverState *bs);
+/* helper used to forbid external snapshots like in blkverify */
+ExtSnapshotPerm bdrv_check_ext_snapshot_forbidden(BlockDriverState *bs);
+
/* async block I/O */
typedef void BlockDriverDirtyHandler(BlockDriverState *bs, int64_t sector,
int sector_num);
@@ -67,6 +67,12 @@ typedef struct BdrvTrackedRequest {
struct BlockDriver {
const char *format_name;
int instance_size;
+
+ /* if not defined external snapshots are allowed
+ * future block filters will query their children to build the response
+ */
+ ExtSnapshotPerm (*bdrv_check_ext_snapshot)(BlockDriverState *bs);
+
int (*bdrv_probe)(const uint8_t *buf, int buf_size, const char *filename);
int (*bdrv_probe_device)(const char *filename);