From: MORITA Kazutaka <morita.kazut...@lab.ntt.co.jp>
Sheepdog vdi snapshot works as follows:
1. Update the inode header of the current working vdi.
2. Create a new working vdi as a child of the previous one.
If QEMU reads the vdi object between 1 and 2, sheep returns
SD_RES_NO_VDI. To avoid this problem, SD_OP_GET_INFO must be ordered
with other vdi operations.
Signed-off-by: MORITA Kazutaka <morita.kazut...@lab.ntt.co.jp>
---
sheep/ops.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/sheep/ops.c b/sheep/ops.c
index 7f27bc3..64dad68 100644
--- a/sheep/ops.c
+++ b/sheep/ops.c
@@ -196,7 +196,15 @@ static int post_cluster_del_vdi(const struct sd_req *req,
struct sd_rsp *rsp,
return ret;
}
-static int local_get_vdi_info(struct request *req)
+/*
+ * Look up vid and copy number from vdi name
+ *
+ * This must be a cluster operation. If QEMU reads the vdi object
+ * while sheep snapshots the vdi, sheep can return SD_RES_NO_VDI. To
+ * avoid this problem, SD_OP_GET_INFO must be ordered with
+ * SD_OP_NEW_VDI.
+ */
+static int cluster_get_vdi_info(struct request *req)
{
const struct sd_req *hdr = &req->rq;
struct sd_rsp *rsp = &req->rp;
@@ -1092,19 +1100,19 @@ static struct sd_op_template sd_ops[] = {
.process_main = cluster_recovery_completion,
},
- /* local operations */
[SD_OP_GET_VDI_INFO] = {
.name = "GET_VDI_INFO",
- .type = SD_OP_TYPE_LOCAL,
- .process_work = local_get_vdi_info,
+ .type = SD_OP_TYPE_CLUSTER,
+ .process_work = cluster_get_vdi_info,
},
[SD_OP_LOCK_VDI] = {
.name = "LOCK_VDI",
- .type = SD_OP_TYPE_LOCAL,
- .process_work = local_get_vdi_info,
+ .type = SD_OP_TYPE_CLUSTER,
+ .process_work = cluster_get_vdi_info,
},
+ /* local operations */
[SD_OP_RELEASE_VDI] = {
.name = "RELEASE_VDI",
.type = SD_OP_TYPE_LOCAL,
--
1.7.9.5
--
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