[Qemu-devel] [PATCH 2/3] sheep: teach sheep to discard unused objects

[Liu Yuan <namei.unix@gmail.com>]

From: Liu Yuan <tailai.ly@taobao.com>

Signed-off-by: Liu Yuan <tailai.ly@taobao.com>
---
 include/sheepdog_proto.h |    1 +
 sheep/ops.c              |   20 ++++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/include/sheepdog_proto.h b/include/sheepdog_proto.h
index f3d69e1..99a6627 100644
--- a/include/sheepdog_proto.h
+++ b/include/sheepdog_proto.h
@@ -35,6 +35,7 @@
 #define SD_OP_GET_VDI_INFO   0x14
 #define SD_OP_READ_VDIS      0x15
 #define SD_OP_FLUSH_VDI      0x16
+#define SD_OP_DISCARD        0x17
 
 #define SD_FLAG_CMD_WRITE    0x01
 #define SD_FLAG_CMD_COW      0x02
diff --git a/sheep/ops.c b/sheep/ops.c
index a0502b2..8f6b0c1 100644
--- a/sheep/ops.c
+++ b/sheep/ops.c
@@ -741,6 +741,20 @@ static int local_flush_vdi(struct request *req)
 	return ret;
 }
 
+static int local_discard(struct request *req)
+{
+	uint64_t oid = req->rq.obj.oid;
+	uint32_t vid = oid_to_vid(oid), zero = 0;
+	int ret, cp = get_vdi_copy_number(vid), idx = data_oid_to_idx(oid);
+
+	sd_dprintf("%"PRIx64, oid);
+	ret = remove_object(oid, cp);
+	if (ret != SD_RES_SUCCESS)
+		return ret;
+	return write_object(vid_to_vdi_oid(vid), (char *)&zero, sizeof(zero),
+			    SD_INODE_HEADER_SIZE + sizeof(vid) * idx, 0, cp);
+}
+
 static int local_flush_and_del(struct request *req)
 {
 	if (!sys->enable_object_cache)
@@ -1109,6 +1123,12 @@ static struct sd_op_template sd_ops[] = {
 		.process_work = local_flush_vdi,
 	},
 
+	[SD_OP_DISCARD] = {
+		.name = "DISCARD",
+		.type = SD_OP_TYPE_LOCAL,
+		.process_work = local_discard,
+	},
+
 	[SD_OP_FLUSH_DEL_CACHE] = {
 		.name = "DEL_CACHE",
 		.type = SD_OP_TYPE_LOCAL,
-- 
1.7.9.5