[sheepdog] read/write during recovery

[Dietmar Maurer]

> On 07/24/2012 03:48 PM, Dietmar Maurer wrote:
> > Why do you think so? It basically make things easier, and just remove
> > lines of code.
> 
> It is just my estimation, I'd like to see real code.

I think we can reject requests until we really start recovering an object, because
the data is stored on the other nodes anyways.

I have to say that I still not fully understand all code, so please forgive me if I post 
nonsense ;-)

My naïve patch looks like this (can be optimized further):

From 0972d52d7a86cd2a265ae2a91592c36e853e7436 Mon Sep 17 00:00:00 2001
From: Dietmar Maurer <dietmar at proxmox.com>
Date: Tue, 24 Jul 2012 13:17:47 +0200
Subject: [PATCH] only queue commands when necessary

We do not need to queue commands until we start recovering a specific object.

Signed-off-by: Dietmar Maurer <dietmar at proxmox.com>
---
 sheep/recovery.c   |   13 ++++++++++---
 sheep/request.c    |    2 +-
 sheep/sheep_priv.h |    2 +-
 3 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/sheep/recovery.c b/sheep/recovery.c
index dd17edd..f2e2688 100644
--- a/sheep/recovery.c
+++ b/sheep/recovery.c
@@ -242,11 +242,18 @@ int node_in_recovery(void)
 	return !!recovering_work;
 }
 
-int is_recovery_init(void)
+int is_recovery_init(uint64_t oid)
 {
 	struct recovery_work *rw = recovering_work;
 
-	return rw->state == RW_INIT;
+	if (rw->state == RW_INIT)
+		return 1;
+
+	/* The oid is currently being recovered */
+	if (rw->oids[rw->done] == oid)
+		return 0;
+
+	return 1;
 }
 
 static inline void prepare_schedule_oid(uint64_t oid)
@@ -312,7 +319,7 @@ bool oid_in_recovery(uint64_t oid)
 		return false;
 	}
 
-	prepare_schedule_oid(oid);
+	//prepare_schedule_oid(oid);
 	return true;
 }
 
diff --git a/sheep/request.c b/sheep/request.c
index 0fa5795..3865d4a 100644
--- a/sheep/request.c
+++ b/sheep/request.c
@@ -150,7 +150,7 @@ static bool request_in_recovery(struct request *req)
 		/*
 		 * Put request on wait queues of local node
 		 */
-		if (is_recovery_init()) {
+		if (is_recovery_init(req->local_oid)) {
 			req->rp.result = SD_RES_OBJ_RECOVERING;
 			list_add_tail(&req->request_list,
 				      &sys->wait_rw_queue);
diff --git a/sheep/sheep_priv.h b/sheep/sheep_priv.h
index e455d27..abebc69 100644
--- a/sheep/sheep_priv.h
+++ b/sheep/sheep_priv.h
@@ -260,7 +260,7 @@ int start_recovery(struct vnode_info *cur_vnodes,
 	struct vnode_info *old_vnodes);
 void resume_recovery_work(void);
 bool oid_in_recovery(uint64_t oid);
-int is_recovery_init(void);
+int is_recovery_init(uint64_t oid);
 int node_in_recovery(void);
 
 int write_object(uint64_t oid, char *data, unsigned int datalen,
-- 
1.7.2.5