[sheepdog] [PATCH 1/3] sheep: introduce ec_max_data_strip

[Liu Yuan]

This is a preparation patch

Signed-off-by: Liu Yuan <namei.unix at gmail.com>
---
 sheep/ops.c        |    3 ++-
 sheep/sheep_priv.h |    1 +
 sheep/vdi.c        |   14 ++++++++++++++
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/sheep/ops.c b/sheep/ops.c
index 7f73ab1..d8c652b 100644
--- a/sheep/ops.c
+++ b/sheep/ops.c
@@ -676,7 +676,8 @@ static int cluster_recovery_completion(const struct sd_req *req,
 			sd_debug("all nodes are recovered, epoch %d", epoch);
 			last_gathered_epoch = epoch;
 			/* sd_store can be NULL if this node is a gateway */
-			if (sd_store && sd_store->cleanup)
+			if (vnode_info->nr_zones >= ec_max_data_strip &&
+			    sd_store && sd_store->cleanup)
 				sd_store->cleanup();
 		}
 	}
diff --git a/sheep/sheep_priv.h b/sheep/sheep_priv.h
index 615d912..0c44651 100644
--- a/sheep/sheep_priv.h
+++ b/sheep/sheep_priv.h
@@ -296,6 +296,7 @@ int vdi_snapshot(const struct vdi_iocb *iocb, uint32_t *new_vid);
 int vdi_delete(const struct vdi_iocb *iocb, struct request *req);
 int vdi_lookup(const struct vdi_iocb *iocb, struct vdi_info *info);
 void clean_vdi_state(void);
+extern int ec_max_data_strip;
 
 int read_vdis(char *data, int len, unsigned int *rsp_len);
 
diff --git a/sheep/vdi.c b/sheep/vdi.c
index 221905d..3b39247 100644
--- a/sheep/vdi.c
+++ b/sheep/vdi.c
@@ -22,6 +22,13 @@ struct vdi_state_entry {
 static struct rb_root vdi_state_root = RB_ROOT;
 static struct sd_lock vdi_state_lock = SD_LOCK_INITIALIZER;
 
+/*
+ * ec_max_data_strip represent max number of data strips in the cluster. When
+ * nr_zones < it, we don't purge the stale objects because for erasure coding,
+ * there is only one copy of data.
+ */
+int ec_max_data_strip;
+
 static int vdi_state_cmp(const struct vdi_state_entry *a,
 			 const struct vdi_state_entry *b)
 {
@@ -126,6 +133,13 @@ int add_vdi_state(uint32_t vid, int nr_copies, bool snapshot, uint8_t cp)
 	entry->snapshot = snapshot;
 	entry->copy_policy = cp;
 
+	if (cp) {
+		int d;
+
+		ec_policy_to_dp(cp, &d, NULL);
+		ec_max_data_strip = MAX(d, ec_max_data_strip);
+	}
+
 	sd_debug("%" PRIx32 ", %d, %d", vid, nr_copies, cp);
 
 	sd_write_lock(&vdi_state_lock);
-- 
1.7.9.5