[sheepdog] [PATCH stable-0.9] Make the vdi lock mechanism optional

[Hitoshi Mitake]

From: Wang Zhengyong <wangzhengyong at cmss.chinamobile.com>

Current sheepdog driver will send LOCK_VDI/RELEASE_VDI ops,
while start/stop QEMU VM with sheepdog protocol, this mechanism
will lead qemu-img/qemu-io report error when the sheepdog VDI is locking

To keep backward compatiblity, this patch modify the functionality
that make the vdi lock mechanism optional(with --lock opention),
default VDI lock is disabled

Enable VDI lock:
e.g. dog cluster format --lock

Cc: Hitoshi Mitake <mitake.hitoshi at gmail.com>
Signed-off-by: Wang Zhengyong <wangzhengyong at cmss.chinamobile.com>
Signed-off-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>

Conflicts:
	dog/cluster.c
	include/internal_proto.h

Conflicts were resolved by Hitoshi Mitake.
Signed-off-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>
---
 dog/cluster.c            |  9 ++++++++-
 include/internal_proto.h |  1 +
 sheep/ops.c              | 10 ++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/dog/cluster.c b/dog/cluster.c
index e42bc54..ad61295 100644
--- a/dog/cluster.c
+++ b/dog/cluster.c
@@ -21,6 +21,7 @@ static struct sd_option cluster_options[] = {
 	{'b', "store", true, "specify backend store"},
 	{'c', "copies", true, "specify the default data redundancy (number of copies)"},
 	{'f', "force", false, "do not prompt for confirmation"},
+	{'l', "lock", false, "Lock vdi to exclude multiple users"},
 	{'m', "multithread", false,
 	 "use multi-thread for 'cluster snapshot save'"},
 	{'t', "strict", false,
@@ -35,6 +36,7 @@ static struct cluster_cmd_data {
 	bool force;
 	bool strict;
 	char name[STORE_LEN];
+	bool use_lock;
 } cluster_cmd_data;
 
 #define DEFAULT_STORE	"plain"
@@ -123,6 +125,8 @@ static int cluster_format(int argc, char **argv)
 	hdr.flags |= SD_FLAG_CMD_WRITE;
 	if (cluster_cmd_data.strict)
 		hdr.cluster.flags |= SD_CLUSTER_FLAG_STRICT;
+	if (cluster_cmd_data.use_lock)
+		hdr.cluster.flags |= SD_CLUSTER_FLAG_USE_LOCK;
 
 #ifdef HAVE_DISKVNODES
 	hdr.cluster.flags |= SD_CLUSTER_FLAG_DISKMODE;
@@ -752,7 +756,7 @@ failure:
 static struct subcommand cluster_cmd[] = {
 	{"info", NULL, "aprhvT", "show cluster information",
 	 NULL, CMD_NEED_NODELIST, cluster_info, cluster_options},
-	{"format", NULL, "bctaphT", "create a Sheepdog store",
+	{"format", NULL, "bcltaphT", "create a Sheepdog store",
 	 NULL, CMD_NEED_NODELIST, cluster_format, cluster_options},
 	{"shutdown", NULL, "aphT", "stop Sheepdog",
 	 NULL, 0, cluster_shutdown, cluster_options},
@@ -797,6 +801,9 @@ static int cluster_parser(int ch, const char *opt)
 	case 'f':
 		cluster_cmd_data.force = true;
 		break;
+	case 'l':
+		cluster_cmd_data.use_lock = true;
+		break;
 	case 'm':
 		cluster_cmd_data.multithread = true;
 	case 't':
diff --git a/include/internal_proto.h b/include/internal_proto.h
index 85f66b8..151f8cd 100644
--- a/include/internal_proto.h
+++ b/include/internal_proto.h
@@ -142,6 +142,7 @@
 
 #define SD_CLUSTER_FLAG_STRICT		0x0001 /* Strict mode for write */
 #define SD_CLUSTER_FLAG_DISKMODE	0x0002 /* Disk mode for cluster */
+#define SD_CLUSTER_FLAG_USE_LOCK	0x0008 /* Lock/Unlock vdi */
 
 enum sd_status {
 	SD_STATUS_OK = 1,
diff --git a/sheep/ops.c b/sheep/ops.c
index b039c58..9e038f6 100644
--- a/sheep/ops.c
+++ b/sheep/ops.c
@@ -1344,6 +1344,11 @@ static int cluster_lock_vdi_main(const struct sd_req *req, struct sd_rsp *rsp,
 		return SD_RES_SUCCESS;
 	}
 
+	if (!(sys->cinfo.flags & SD_CLUSTER_FLAG_USE_LOCK)) {
+		sd_debug("vdi lock is disabled");
+		return SD_RES_SUCCESS;
+	}
+
 	sd_info("node: %s is locking VDI (type: %s): %"PRIx32,
 		node_to_str(sender),
 		req->vdi.type == LOCK_TYPE_NORMAL ? "normal" : "shared", vid);
@@ -1368,6 +1373,11 @@ static int cluster_release_vdi_main(const struct sd_req *req,
 		return SD_RES_SUCCESS;
 	}
 
+	if (!(sys->cinfo.flags & SD_CLUSTER_FLAG_USE_LOCK)) {
+		sd_debug("vdi lock is disabled");
+		return SD_RES_SUCCESS;
+	}
+
 	sd_info("node: %s is unlocking VDI (type: %s): %"PRIx32, node_to_str(sender),
 		req->vdi.type == LOCK_TYPE_NORMAL ? "normal" : "shared", vid);
 
-- 
1.9.1