@@ -97,6 +97,12 @@ typedef struct RBDTask {
int64_t ret;
} RBDTask;
+typedef struct RBDDiffIterateReq {
+ uint64_t offs;
+ uint64_t bytes;
+ bool exists;
+} RBDDiffIterateReq;
+
static int qemu_rbd_connect(rados_t *cluster, rados_ioctx_t *io_ctx,
BlockdevOptionsRbd *opts, bool cache,
const char *keypairs, const char *secretid,
@@ -1259,6 +1265,111 @@ static ImageInfoSpecific *qemu_rbd_get_specific_info(BlockDriverState *bs,
return spec_info;
}
+/*
+ * rbd_diff_iterate2 allows to interrupt the exection by returning a negative
+ * value in the callback routine. Choose a value that does not conflict with
+ * an existing exitcode and return it if we want to prematurely stop the
+ * execution because we detected a change in the allocation status.
+ */
+#define QEMU_RBD_EXIT_DIFF_ITERATE2 -9000
+
+static int qemu_rbd_diff_iterate_cb(uint64_t offs, size_t len,
+ int exists, void *opaque)
+{
+ RBDDiffIterateReq *req = opaque;
+
+ assert(req->offs + req->bytes <= offs);
+ /*
+ * we do not diff against a snapshot so we should never receive a callback
+ * for a hole.
+ */
+ assert(exists);
+
+ if (!req->exists && offs > req->offs) {
+ /*
+ * we started in an unallocated area and hit the first allocated
+ * block. req->bytes must be set to the length of the unallocated area
+ * before the allocated area. stop further processing.
+ */
+ req->bytes = offs - req->offs;
+ return QEMU_RBD_EXIT_DIFF_ITERATE2;
+ }
+
+ if (req->exists && offs > req->offs + req->bytes) {
+ /*
+ * we started in an allocated area and jumped over an unallocated area,
+ * req->bytes contains the length of the allocated area before the
+ * unallocated area. stop further processing.
+ */
+ return QEMU_RBD_EXIT_DIFF_ITERATE2;
+ }
+
+ req->bytes += len;
+ req->exists = true;
+
+ return 0;
+}
+
+static int coroutine_fn qemu_rbd_co_block_status(BlockDriverState *bs,
+ bool want_zero, int64_t offset,
+ int64_t bytes, int64_t *pnum,
+ int64_t *map,
+ BlockDriverState **file)
+{
+ BDRVRBDState *s = bs->opaque;
+ int status, r;
+ RBDDiffIterateReq req = { .offs = offset };
+ uint64_t features, flags;
+
+ assert(offset + bytes <= s->image_size);
+
+ /* default to all sectors allocated */
+ status = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
+ *map = offset;
+ *file = bs;
+ *pnum = bytes;
+
+ /* check if RBD image supports fast-diff */
+ r = rbd_get_features(s->image, &features);
+ if (r < 0) {
+ return status;
+ }
+ if (!(features & RBD_FEATURE_FAST_DIFF)) {
+ return status;
+ }
+
+ /* check if RBD fast-diff result is valid */
+ r = rbd_get_flags(s->image, &flags);
+ if (r < 0) {
+ return status;
+ }
+ if (flags & RBD_FLAG_FAST_DIFF_INVALID) {
+ return status;
+ }
+
+ r = rbd_diff_iterate2(s->image, NULL, offset, bytes, true, true,
+ qemu_rbd_diff_iterate_cb, &req);
+ if (r < 0 && r != QEMU_RBD_EXIT_DIFF_ITERATE2) {
+ return status;
+ }
+ assert(req.bytes <= bytes);
+ if (!req.exists) {
+ if (r == 0) {
+ /*
+ * rbd_diff_iterate2 does not invoke callbacks for unallocated
+ * areas. This here catches the case where no callback was
+ * invoked at all (req.bytes == 0).
+ */
+ assert(req.bytes == 0);
+ req.bytes = bytes;
+ }
+ status = BDRV_BLOCK_ZERO | BDRV_BLOCK_OFFSET_VALID;
+ }
+
+ *pnum = req.bytes;
+ return status;
+}
+
static int64_t qemu_rbd_getlength(BlockDriverState *bs)
{
BDRVRBDState *s = bs->opaque;
@@ -1494,6 +1605,7 @@ static BlockDriver bdrv_rbd = {
#ifdef LIBRBD_SUPPORTS_WRITE_ZEROES
.bdrv_co_pwrite_zeroes = qemu_rbd_co_pwrite_zeroes,
#endif
+ .bdrv_co_block_status = qemu_rbd_co_block_status,
.bdrv_snapshot_create = qemu_rbd_snap_create,
.bdrv_snapshot_delete = qemu_rbd_snap_remove,