libgfapi: Added support to fetch volume info from glusterd and store in glfs object.

Defined new APIs in the libgfapi module, given a glfs object,
 * to send handshake RPC call to glusterd process to fetch UUID of the volume
 * store it in the glusterfs_context linked to the glfs object.
 * to parse UUID from its cannonical string format into 16-byte array
   before sending it to the libgfapi users.

Defined a RPC call in glusterd which can be used to query volume related
info by other processes using 'clnt_handshake_procs'.

Note - Currently this RPC call to glusterd process is used only to fetch UUID.
But it can be extended to get other volume related structures as well.

In addition to the above, defined a new variable to keep track of such handshake
RPCs still in progress to make sure all the corresponding RPC callbacks have been
processed before libgfapi returns the glfs object initialized.

Also bumping up the GFAPI current version number since there is a new API
"glfs_get_volume_id" defined and exposed by libgfapi as part of these changes.

Cherry picked from commit 5adb10b9ac1c634334f29732e062b12d747ae8c5:
> Change-Id: I303f76d7177d32d25bdb301b1dbcf5cd73f42807
> BUG: 1095775
> Signed-off-by: Soumya Koduri <skoduri@redhat.com>
> Reviewed-on: http://review.gluster.org/7218
> Reviewed-by: Anand Avati <avati@redhat.com>
> Reviewed-by: Harshavardhana <harsha@harshavardhana.net>
> Tested-by: Gluster Build System <jenkins@build.gluster.com>
> Reviewed-by: Vijay Bellur <vbellur@redhat.com>

This change differs a little from the patch in the master branch:
- libgfapi in 3.5 does not have glfs_get_volfile(), so there were some
  merge conflicts resolved,
- libgfapi in 3.5 is not versioned, the configure.ac changes related to
  the versioning have been skipped,
- in the master branch only the XDR .x files are available, release-3.5
  requires a manual re-generation of the relates .h and .c files.

Change-Id: I52c32d0e69a52a7f4285f74164bca6fd83c4f3b3
BUG: 1095775
Signed-off-by: Soumya Koduri <skoduri@redhat.com>
Reviewed-on: http://review.gluster.org/7741
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Tested-by: Niels de Vos <ndevos@redhat.com>

8 files changed, 530 insertions, 46 deletions

diff --git a/api/src/glfs-internal.h b/api/src/glfs-internal.h
index ec1d5579df7..6ed4aeae16f 100644
--- a/api/src/glfs-internal.h
+++ b/api/src/glfs-internal.h
@@ -60,6 +60,7 @@ typedef int (*glfs_init_cbk) (struct glfs *fs, int ret);
 
 struct glfs {
 	char               *volname;
+        uuid_t              vol_uuid;
 
 	glusterfs_ctx_t    *ctx;
 
@@ -197,4 +198,7 @@ void glfs_iatt_to_stat (struct glfs *fs, struct iatt *iatt, struct stat *stat);
 int glfs_loc_link (loc_t *loc, struct iatt *iatt);
 int glfs_loc_unlink (loc_t *loc);
 
+/* Sends RPC call to glusterd to fetch required volume info */
+int glfs_get_volume_info (struct glfs *fs);
+
 #endif /* !_GLFS_INTERNAL_H */
diff --git a/api/src/glfs-mgmt.c b/api/src/glfs-mgmt.c
index 5493e89db81..2557186ebd8 100644
--- a/api/src/glfs-mgmt.c
+++ b/api/src/glfs-mgmt.c
@@ -22,6 +22,7 @@
 #endif /* _CONFIG_H */
 
 #include "glusterfs.h"
+#include "glfs.h"
 #include "stack.h"
 #include "dict.h"
 #include "event.h"
@@ -39,8 +40,9 @@
 #include "glfs-internal.h"
 #include "glfs-mem-types.h"
 
-
 int glfs_volfile_fetch (struct glfs *fs);
+int32_t glfs_get_volume_info_rpc (call_frame_t *frame, xlator_t *this,
+                                  struct glfs *fs);
 
 int
 glfs_process_volfp (struct glfs *fs, FILE *fp)
@@ -135,6 +137,7 @@ char *clnt_handshake_procs[GF_HNDSK_MAXVALUE] = {
 	[GF_HNDSK_GETSPEC]	= "GETSPEC",
 	[GF_HNDSK_PING]		= "PING",
 	[GF_HNDSK_EVENT_NOTIFY] = "EVENTNOTIFY",
+        [GF_HNDSK_GET_VOLUME_INFO] = "GETVOLUMEINFO",
 };
 
 rpc_clnt_prog_t clnt_handshake_prog = {
@@ -201,6 +204,249 @@ out:
 	return ret;
 }
 
+/*
+ * Callback routine for 'GF_HNDSK_GET_VOLUME_INFO' rpc request
+ */
+int
+mgmt_get_volinfo_cbk (struct rpc_req *req, struct iovec *iov,
+                      int count, void *myframe)
+{
+        int                        ret                  = 0;
+        char                       *volume_id_str       = NULL;
+        dict_t                     *dict                = NULL;
+        char                       key[1024]            = {0};
+        gf_get_volume_info_rsp     rsp                  = {0,};
+        call_frame_t               *frame               = NULL;
+        glusterfs_ctx_t            *ctx                 = NULL;
+        struct glfs                *fs                  = NULL;
+        struct syncargs            *args;
+
+        frame = myframe;
+        ctx = frame->this->ctx;
+        args = frame->local;
+
+        if (!ctx) {
+                gf_log (frame->this->name, GF_LOG_ERROR, "NULL context");
+                errno = EINVAL;
+                ret = -1;
+                goto out;
+        }
+
+        fs = ((xlator_t *)ctx->master)->private;
+
+        if (-1 == req->rpc_status) {
+                gf_log (frame->this->name, GF_LOG_ERROR,
+                        "GET_VOLUME_INFO RPC call is not successfull");
+                errno = EINVAL;
+                ret = -1;
+                goto out;
+        }
+
+        ret = xdr_to_generic (*iov, &rsp, (xdrproc_t)xdr_gf_get_volume_info_rsp);
+
+        if (ret < 0) {
+                gf_log (frame->this->name, GF_LOG_ERROR,
+                        "Failed to decode xdr response for GET_VOLUME_INFO");
+                goto out;
+        }
+
+        gf_log (frame->this->name, GF_LOG_DEBUG,
+                "Received resp to GET_VOLUME_INFO RPC: %d", rsp.op_ret);
+
+        if (rsp.op_ret == -1) {
+                errno = rsp.op_errno;
+                ret = -1;
+                goto out;
+        }
+
+        if (!rsp.dict.dict_len) {
+                gf_log (frame->this->name, GF_LOG_ERROR,
+                        "Response received for GET_VOLUME_INFO RPC call is not valid");
+                ret = -1;
+                errno = EINVAL;
+                goto out;
+        }
+
+        dict = dict_new ();
+
+        if (!dict) {
+                ret = -1;
+                errno = ENOMEM;
+                goto out;
+        }
+
+        ret = dict_unserialize (rsp.dict.dict_val,
+                                rsp.dict.dict_len,
+                                &dict);
+
+        if (ret) {
+                errno = ENOMEM;
+                goto out;
+        }
+
+        snprintf (key, sizeof (key), "volume_id");
+        ret = dict_get_str (dict, key, &volume_id_str);
+        if (ret) {
+                errno = EINVAL;
+                goto out;
+        }
+
+        ret = 0;
+out:
+        if (volume_id_str) {
+                gf_log (frame->this->name, GF_LOG_DEBUG,
+                        "Volume Id: %s", volume_id_str);
+                pthread_mutex_lock (&fs->mutex);
+                uuid_parse (volume_id_str, fs->vol_uuid);
+                pthread_mutex_unlock (&fs->mutex);
+        }
+
+        if (ret) {
+               gf_log (frame->this->name, GF_LOG_ERROR,
+                       "In GET_VOLUME_INFO cbk, received error: %s",
+                       strerror(errno));
+        }
+
+        if (dict)
+                dict_destroy (dict);
+
+        if (rsp.dict.dict_val)
+                free (rsp.dict.dict_val);
+
+        if (rsp.op_errstr && *rsp.op_errstr)
+                free (rsp.op_errstr);
+
+        gf_log (frame->this->name, GF_LOG_DEBUG, "Returning: %d", ret);
+
+        __wake (args);
+
+        return ret;
+}
+
+int
+glfs_get_volumeid (struct glfs *fs, char *volid, size_t size)
+{
+        /* TODO: Define a global macro to store UUID size */
+        size_t uuid_size = 16;
+
+        pthread_mutex_lock (&fs->mutex);
+        {
+                /* check if the volume uuid is initialized */
+                if (!uuid_is_null (fs->vol_uuid)) {
+                        pthread_mutex_unlock (&fs->mutex);
+                        goto done;
+                }
+        }
+        pthread_mutex_unlock (&fs->mutex);
+
+        /* Need to fetch volume_uuid */
+        glfs_get_volume_info (fs);
+
+        if (uuid_is_null (fs->vol_uuid)) {
+                gf_log (THIS->name, GF_LOG_ERROR, "Unable to fetch volume UUID");
+                return -1;
+        }
+
+done:
+        if (!volid || !size) {
+                gf_log (THIS->name, GF_LOG_DEBUG, "volumeid/size is null");
+                return uuid_size;
+        }
+
+        if (size < uuid_size) {
+                gf_log (THIS->name, GF_LOG_ERROR, "Insufficient size passed");
+                errno = ERANGE;
+                return -1;
+        }
+
+        memcpy (volid, fs->vol_uuid, uuid_size);
+
+        gf_log (THIS->name, GF_LOG_INFO, "volume uuid: %s", volid);
+
+        return uuid_size;
+}
+
+int
+glfs_get_volume_info (struct glfs *fs)
+{
+        call_frame_t     *frame = NULL;
+        glusterfs_ctx_t  *ctx   = NULL;
+        struct syncargs  args   = {0, };
+        int              ret    = 0;
+
+        ctx = fs->ctx;
+        frame = create_frame (THIS, ctx->pool);
+        frame->local = &args;
+
+        __yawn ((&args));
+
+        ret = glfs_get_volume_info_rpc (frame, THIS, fs);
+        if (ret)
+                goto out;
+
+        __yield ((&args));
+
+        frame->local = NULL;
+        STACK_DESTROY (frame->root);
+
+out:
+        return ret;
+}
+
+int32_t
+glfs_get_volume_info_rpc (call_frame_t *frame, xlator_t *this,
+                          struct glfs *fs)
+{
+        gf_get_volume_info_req  req       = {{0,}};
+        int                     ret       = 0;
+        glusterfs_ctx_t         *ctx      = NULL;
+        dict_t                  *dict     = NULL;
+        int32_t                 flags     = 0;
+
+        if (!frame || !this || !fs) {
+                ret = -1;
+                goto out;
+        }
+
+        ctx = fs->ctx;
+
+        dict = dict_new ();
+        if (!dict) {
+                ret = -1;
+                goto out;
+        }
+
+        if (fs->volname) {
+                ret = dict_set_str (dict, "volname", fs->volname);
+                if (ret)
+                        goto out;
+        }
+
+        // Set the flags for the fields which we are interested in
+        flags = (int32_t)GF_GET_VOLUME_UUID; //ctx->flags;
+        ret = dict_set_int32 (dict, "flags", flags);
+        if (ret) {
+                gf_log (frame->this->name, GF_LOG_ERROR, "failed to set flags");
+                goto out;
+        }
+
+        ret = dict_allocate_and_serialize (dict, &req.dict.dict_val,
+                                           &req.dict.dict_len);
+
+
+        ret = mgmt_submit_request (&req, frame, ctx, &clnt_handshake_prog,
+                                   GF_HNDSK_GET_VOLUME_INFO,
+                                   mgmt_get_volinfo_cbk,
+                                   (xdrproc_t)xdr_gf_get_volume_info_req);
+out:
+        if (dict) {
+                dict_unref (dict);
+        }
+
+        GF_FREE (req.dict.dict_val);
+
+        return ret;
+}
 
 static int
 glusterfs_oldvolfile_update (struct glfs *fs, char *volfile, ssize_t size)
@@ -502,7 +748,7 @@ mgmt_rpc_notify (struct rpc_clnt *rpc, void *mydata, rpc_clnt_event_t event,
 			glfs_init_done (fs, -1);
 		}
 
-		break;
+                break;
 	default:
 		break;
 	}
diff --git a/api/src/glfs.h b/api/src/glfs.h
index 2210c26d34f..964422aab72 100644
--- a/api/src/glfs.h
+++ b/api/src/glfs.h
@@ -257,6 +257,38 @@ int glfs_init (glfs_t *fs);
 
 int glfs_fini (glfs_t *fs);
 
+
+/*
+  SYNOPSIS
+
+       glfs_get_volumeid: Copy the Volume UUID stored in the glfs object fs.
+
+  DESCRIPTION
+
+       This function when invoked for the first time sends RPC call to the
+       the management server (glusterd) to fetch volume uuid and stores it
+       in the glusterfs_context linked to the glfs object fs which can be used
+       in the subsequent calls. Later it parses that UUID to convert it from
+       cannonical string format into an opaque byte array and copy it into
+       the volid array. Incase if either of the input parameters, volid or size,
+       is NULL, number of bytes required to copy the volume UUID is returned.
+
+  PARAMETERS
+
+       @fs: The 'virtual mount' object to be used to retrieve and store
+            volume's UUID.
+       @volid: Pointer to a place for the volume UUID to be stored
+       @size: Length of @volid
+
+  RETURN VALUES
+
+       -1 : Failure. @errno will be set with the type of failure.
+        Others : length of the volume UUID stored.
+*/
+
+int glfs_get_volumeid (struct glfs *fs, char *volid, size_t size);
+
+
 /*
  * FILE OPERATION
  *
diff --git a/rpc/rpc-lib/src/protocol-common.h b/rpc/rpc-lib/src/protocol-common.h
index 5876a500bdf..d44de48377c 100644
--- a/rpc/rpc-lib/src/protocol-common.h
+++ b/rpc/rpc-lib/src/protocol-common.h
@@ -69,6 +69,7 @@ enum gf_handshake_procnum {
         GF_HNDSK_PING,
         GF_HNDSK_SET_LK_VER,
         GF_HNDSK_EVENT_NOTIFY,
+        GF_HNDSK_GET_VOLUME_INFO,
         GF_HNDSK_MAXVALUE,
 };
 
@@ -238,6 +239,13 @@ struct gf_gsync_detailed_status_ {
 
 typedef struct gf_gsync_detailed_status_ gf_gsync_status_t;
 
+enum gf_get_volume_info_type {
+        GF_GET_VOLUME_NONE,    /* 0 */
+        GF_GET_VOLUME_UUID
+};
+
+typedef enum gf_get_volume_info_type gf_get_volume_info_type;
+
 #define GLUSTER_HNDSK_PROGRAM    14398633 /* Completely random */
 #define GLUSTER_HNDSK_VERSION    2   /* 0.0.2 */
 
diff --git a/rpc/xdr/src/glusterfs3-xdr.c b/rpc/xdr/src/glusterfs3-xdr.c
index 3205c551e5b..45efd860a0d 100644
--- a/rpc/xdr/src/glusterfs3-xdr.c
+++ b/rpc/xdr/src/glusterfs3-xdr.c
@@ -1587,44 +1587,41 @@ xdr_gfs3_discard_rsp (XDR *xdrs, gfs3_discard_rsp *objp)
 bool_t
 xdr_gfs3_zerofill_req (XDR *xdrs, gfs3_zerofill_req *objp)
 {
-        register int32_t *buf;
+	register int32_t *buf;
         buf = NULL;
 
-        if (!xdr_opaque (xdrs, objp->gfid, 16))
-                return FALSE;
-        if (!xdr_quad_t (xdrs, &objp->fd))
-                return FALSE;
-        if (!xdr_u_quad_t (xdrs, &objp->offset))
-                return FALSE;
-        if (!xdr_u_quad_t (xdrs, &objp->size))
-                return FALSE;
-        if (!xdr_bytes (xdrs, (char **)&objp->xdata.xdata_val,
-             (u_int *) &objp->xdata.xdata_len, ~0))
-                return FALSE;
-        return TRUE;
+	 if (!xdr_opaque (xdrs, objp->gfid, 16))
+		 return FALSE;
+	 if (!xdr_quad_t (xdrs, &objp->fd))
+		 return FALSE;
+	 if (!xdr_u_quad_t (xdrs, &objp->offset))
+		 return FALSE;
+	 if (!xdr_u_quad_t (xdrs, &objp->size))
+		 return FALSE;
+	 if (!xdr_bytes (xdrs, (char **)&objp->xdata.xdata_val, (u_int *) &objp->xdata.xdata_len, ~0))
+		 return FALSE;
+	return TRUE;
 }
 
 bool_t
 xdr_gfs3_zerofill_rsp (XDR *xdrs, gfs3_zerofill_rsp *objp)
 {
-        register int32_t *buf;
+	register int32_t *buf;
         buf = NULL;
 
-        if (!xdr_int (xdrs, &objp->op_ret))
-                return FALSE;
-        if (!xdr_int (xdrs, &objp->op_errno))
-                return FALSE;
-        if (!xdr_gf_iatt (xdrs, &objp->statpre))
-                return FALSE;
-        if (!xdr_gf_iatt (xdrs, &objp->statpost))
-                return FALSE;
-        if (!xdr_bytes (xdrs, (char **)&objp->xdata.xdata_val,
-             (u_int *) &objp->xdata.xdata_len, ~0))
-                return FALSE;
-        return TRUE;
+	 if (!xdr_int (xdrs, &objp->op_ret))
+		 return FALSE;
+	 if (!xdr_int (xdrs, &objp->op_errno))
+		 return FALSE;
+	 if (!xdr_gf_iatt (xdrs, &objp->statpre))
+		 return FALSE;
+	 if (!xdr_gf_iatt (xdrs, &objp->statpost))
+		 return FALSE;
+	 if (!xdr_bytes (xdrs, (char **)&objp->xdata.xdata_val, (u_int *) &objp->xdata.xdata_len, ~0))
+		 return FALSE;
+	return TRUE;
 }
 
-
 bool_t
 xdr_gfs3_rchecksum_req (XDR *xdrs, gfs3_rchecksum_req *objp)
 {
@@ -1763,6 +1760,34 @@ xdr_gf_getspec_rsp (XDR *xdrs, gf_getspec_rsp *objp)
 }
 
 bool_t
+xdr_gf_get_volume_info_req (XDR *xdrs, gf_get_volume_info_req *objp)
+{
+	register int32_t *buf;
+        buf = NULL;
+
+	 if (!xdr_bytes (xdrs, (char **)&objp->dict.dict_val, (u_int *) &objp->dict.dict_len, ~0))
+		 return FALSE;
+	return TRUE;
+}
+
+bool_t
+xdr_gf_get_volume_info_rsp (XDR *xdrs, gf_get_volume_info_rsp *objp)
+{
+	register int32_t *buf;
+        buf = NULL;
+
+	 if (!xdr_int (xdrs, &objp->op_ret))
+		 return FALSE;
+	 if (!xdr_int (xdrs, &objp->op_errno))
+		 return FALSE;
+	 if (!xdr_string (xdrs, &objp->op_errstr, ~0))
+		 return FALSE;
+	 if (!xdr_bytes (xdrs, (char **)&objp->dict.dict_val, (u_int *) &objp->dict.dict_len, ~0))
+		 return FALSE;
+	return TRUE;
+}
+
+bool_t
 xdr_gf_mgmt_hndsk_req (XDR *xdrs, gf_mgmt_hndsk_req *objp)
 {
 	register int32_t *buf;
diff --git a/rpc/xdr/src/glusterfs3-xdr.h b/rpc/xdr/src/glusterfs3-xdr.h
index 13566e69447..ac74cca5cc1 100644
--- a/rpc/xdr/src/glusterfs3-xdr.h
+++ b/rpc/xdr/src/glusterfs3-xdr.h
@@ -937,30 +937,29 @@ struct gfs3_discard_rsp {
 typedef struct gfs3_discard_rsp gfs3_discard_rsp;
 
 struct gfs3_zerofill_req {
-        char gfid[16];
-        quad_t fd;
-        u_quad_t offset;
-        u_quad_t size;
-        struct {
-                u_int xdata_len;
-                char *xdata_val;
-        } xdata;
+	char gfid[16];
+	quad_t fd;
+	u_quad_t offset;
+	u_quad_t size;
+	struct {
+		u_int xdata_len;
+		char *xdata_val;
+	} xdata;
 };
 typedef struct gfs3_zerofill_req gfs3_zerofill_req;
 
 struct gfs3_zerofill_rsp {
-        int op_ret;
-        int op_errno;
-        struct gf_iatt statpre;
-        struct gf_iatt statpost;
-        struct {
-                u_int xdata_len;
-                char *xdata_val;
-        } xdata;
+	int op_ret;
+	int op_errno;
+	struct gf_iatt statpre;
+	struct gf_iatt statpost;
+	struct {
+		u_int xdata_len;
+		char *xdata_val;
+	} xdata;
 };
 typedef struct gfs3_zerofill_rsp gfs3_zerofill_rsp;
 
-
 struct gfs3_rchecksum_req {
 	quad_t fd;
 	u_quad_t offset;
@@ -1026,6 +1025,25 @@ struct gf_getspec_rsp {
 };
 typedef struct gf_getspec_rsp gf_getspec_rsp;
 
+struct gf_get_volume_info_req {
+	struct {
+		u_int dict_len;
+		char *dict_val;
+	} dict;
+};
+typedef struct gf_get_volume_info_req gf_get_volume_info_req;
+
+struct gf_get_volume_info_rsp {
+	int op_ret;
+	int op_errno;
+	char *op_errstr;
+	struct {
+		u_int dict_len;
+		char *dict_val;
+	} dict;
+};
+typedef struct gf_get_volume_info_rsp gf_get_volume_info_rsp;
+
 struct gf_mgmt_hndsk_req {
 	struct {
 		u_int hndsk_len;
@@ -1268,6 +1286,8 @@ extern  bool_t xdr_gf_setvolume_req (XDR *, gf_setvolume_req*);
 extern  bool_t xdr_gf_setvolume_rsp (XDR *, gf_setvolume_rsp*);
 extern  bool_t xdr_gf_getspec_req (XDR *, gf_getspec_req*);
 extern  bool_t xdr_gf_getspec_rsp (XDR *, gf_getspec_rsp*);
+extern  bool_t xdr_gf_get_volume_info_req (XDR *, gf_get_volume_info_req*);
+extern  bool_t xdr_gf_get_volume_info_rsp (XDR *, gf_get_volume_info_rsp*);
 extern  bool_t xdr_gf_mgmt_hndsk_req (XDR *, gf_mgmt_hndsk_req*);
 extern  bool_t xdr_gf_mgmt_hndsk_rsp (XDR *, gf_mgmt_hndsk_rsp*);
 extern  bool_t xdr_gf_log_req (XDR *, gf_log_req*);
@@ -1368,6 +1388,8 @@ extern bool_t xdr_gf_setvolume_req ();
 extern bool_t xdr_gf_setvolume_rsp ();
 extern bool_t xdr_gf_getspec_req ();
 extern bool_t xdr_gf_getspec_rsp ();
+extern bool_t xdr_gf_get_volume_info_req ();
+extern bool_t xdr_gf_get_volume_info_rsp ();
 extern bool_t xdr_gf_mgmt_hndsk_req ();
 extern bool_t xdr_gf_mgmt_hndsk_rsp ();
 extern bool_t xdr_gf_log_req ();
diff --git a/rpc/xdr/src/glusterfs3-xdr.x b/rpc/xdr/src/glusterfs3-xdr.x
index 1edbda3ada9..1c6bf4be244 100644
--- a/rpc/xdr/src/glusterfs3-xdr.x
+++ b/rpc/xdr/src/glusterfs3-xdr.x
@@ -653,6 +653,16 @@ struct gfs3_fstat_req {
         opaque   xdata<>; /* Extra data */
 } ;
 
+ struct gf_get_volume_info_req {
+        opaque   dict<>; /* Extra data */
+}  ;
+ struct  gf_get_volume_info_rsp {
+        int    op_ret;
+        int    op_errno;
+        string op_errstr<>;
+        opaque   dict<>; /* Extra data */
+} ;
+
  struct gf_mgmt_hndsk_req {
         opaque   hndsk<>;
 }  ;
diff --git a/xlators/mgmt/glusterd/src/glusterd-handshake.c b/xlators/mgmt/glusterd/src/glusterd-handshake.c
index 1420eb692ee..87958d0701b 100644
--- a/xlators/mgmt/glusterd/src/glusterd-handshake.c
+++ b/xlators/mgmt/glusterd/src/glusterd-handshake.c
@@ -591,10 +591,147 @@ glusterd_mgmt_hndsk_versions_ack (rpcsvc_request_t *req)
                                             __glusterd_mgmt_hndsk_versions_ack);
 }
 
+int
+__server_get_volume_info (rpcsvc_request_t *req)
+{
+        int                     ret             = -1;
+        int32_t                 op_errno        = ENOENT;
+        gf_get_volume_info_req	vol_info_req    = {{0,}};
+        gf_get_volume_info_rsp	vol_info_rsp    = {0,};
+        char                    *volname        = NULL;
+        glusterd_volinfo_t      *volinfo        = NULL;
+        dict_t                  *dict           = NULL;
+        dict_t                  *dict_rsp       = NULL;
+        char                    *volume_id_str  = NULL;
+        int32_t                 flags           = 0;
+
+        ret = xdr_to_generic (req->msg[0], &vol_info_req,
+                             (xdrproc_t)xdr_gf_get_volume_info_req);
+        if (ret < 0) {
+                //failed to decode msg;
+                req->rpc_err = GARBAGE_ARGS;
+                goto out;
+        }
+        gf_log ("glusterd", GF_LOG_INFO, "Received get volume info req");
+
+        if (vol_info_req.dict.dict_len) {
+                /* Unserialize the dictionary */
+                dict  = dict_new ();
+                if (!dict) {
+                        gf_log ("", GF_LOG_WARNING, "Out of Memory");
+                        op_errno = ENOMEM;
+                        ret = -1;
+                        goto out;
+                }
+
+                ret = dict_unserialize (vol_info_req.dict.dict_val,
+                                        vol_info_req.dict.dict_len,
+                                        &dict);
+                if (ret < 0) {
+                        gf_log ("glusterd", GF_LOG_ERROR,
+                                "failed to "
+                                "unserialize req-buffer to dictionary");
+                        op_errno = -ret;
+                        ret = -1;
+                        goto out;
+                } else {
+                        dict->extra_stdfree = vol_info_req.dict.dict_val;
+                }
+        }
+
+        ret = dict_get_int32 (dict, "flags", &flags);
+        if (ret) {
+                gf_log (THIS->name, GF_LOG_ERROR, "failed to get flags");
+                op_errno = -ret;
+                ret = -1;
+                goto out;
+        }
+
+        if (!flags) {
+                //Nothing to query about. Just return success
+                gf_log (THIS->name, GF_LOG_ERROR, "No flags set");
+                ret = 0;
+                goto out;
+        }
+
+        ret = dict_get_str (dict, "volname", &volname);
+        if (ret) {
+                op_errno = EINVAL;
+                ret = -1;
+                goto out;
+        }
+
+        ret = glusterd_volinfo_find (volname, &volinfo);
+        if (ret) {
+                op_errno = EINVAL;
+                ret = -1;
+                goto out;
+        }
+
+        if (flags | (int32_t)GF_GET_VOLUME_UUID) {
+                volume_id_str = gf_strdup (uuid_utoa (volinfo->volume_id));
+                if (!volume_id_str) {
+                        op_errno = ENOMEM;
+                        ret = -1;
+                        goto out;
+                }
+
+                dict_rsp = dict_new ();
+                if (!dict_rsp) {
+                        gf_log ("", GF_LOG_WARNING, "Out of Memory");
+                        op_errno = ENOMEM;
+                        ret = -1;
+                        goto out;
+                }
+                ret = dict_set_dynstr (dict_rsp, "volume_id", volume_id_str);
+                if (ret) {
+                        op_errno = -ret;
+                        ret = -1;
+                        goto out;
+                }
+        }
+        ret = dict_allocate_and_serialize (dict_rsp, &vol_info_rsp.dict.dict_val,
+                                           &vol_info_rsp.dict.dict_len);
+        if (ret) {
+                op_errno = -ret;
+                ret = -1;
+                goto out;
+        }
+
+out:
+        vol_info_rsp.op_ret = ret;
+        vol_info_rsp.op_errno = op_errno;
+        vol_info_rsp.op_errstr = "";
+        glusterd_submit_reply (req, &vol_info_rsp, NULL, 0, NULL,
+                               (xdrproc_t)xdr_gf_get_volume_info_rsp);
+        ret = 0;
+
+        if (dict) {
+                dict_unref (dict);
+        }
+
+        if (dict_rsp) {
+                dict_unref (dict_rsp);
+        }
+
+        if (vol_info_rsp.dict.dict_val) {
+                GF_FREE (vol_info_rsp.dict.dict_val);
+        }
+        return ret;
+}
+
+int
+server_get_volume_info (rpcsvc_request_t *req)
+{
+        return glusterd_big_locked_handler (req,
+                                            __server_get_volume_info);
+}
+
 rpcsvc_actor_t gluster_handshake_actors[] = {
         [GF_HNDSK_NULL]         = {"NULL",        GF_HNDSK_NULL,         NULL,                NULL, 0, DRC_NA},
         [GF_HNDSK_GETSPEC]      = {"GETSPEC",     GF_HNDSK_GETSPEC,      server_getspec,      NULL, 0, DRC_NA},
         [GF_HNDSK_EVENT_NOTIFY] = {"EVENTNOTIFY", GF_HNDSK_EVENT_NOTIFY, server_event_notify, NULL, 0, DRC_NA},
+        [GF_HNDSK_GET_VOLUME_INFO] = {"GETVOLUMEINFO", GF_HNDSK_GET_VOLUME_INFO, server_get_volume_info, NULL, 0, DRC_NA},
 };