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.

Change-Id: I303f76d7177d32d25bdb301b1dbcf5cd73f42807
BUG: 1090363
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>

3 files changed, 288 insertions, 6 deletions

diff --git a/api/src/glfs-internal.h b/api/src/glfs-internal.h
index 14e94e2116..6fdec961a1 100644
--- a/api/src/glfs-internal.h
+++ b/api/src/glfs-internal.h
@@ -80,6 +80,7 @@ typedef int (*glfs_init_cbk) (struct glfs *fs, int ret);
 
 struct glfs {
 	char               *volname;
+        uuid_t              vol_uuid;
 
 	glusterfs_ctx_t    *ctx;
 
@@ -222,4 +223,7 @@ dict_t * dict_for_key_value (const char *name, const char *value, size_t size);
 int glfs_getxattr_process (void *value, size_t size, dict_t *xattr,
 			   const char *name);
 
+/* 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 5c7e8b2fc2..bb82dc9a18 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"
@@ -40,8 +41,9 @@
 #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)
@@ -136,6 +138,7 @@ 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 = {
@@ -202,6 +205,249 @@ 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)
@@ -514,12 +760,12 @@ mgmt_rpc_notify (struct rpc_clnt *rpc, void *mydata, rpc_clnt_event_t event,
 			/* Exit the process.. there are some wrong options */
 			gf_log ("glfs-mgmt", GF_LOG_ERROR,
 				"failed to fetch volume file (key:%s)",
-				ctx->cmd_args.volfile_id);
-			errno = EINVAL;
-			glfs_init_done (fs, -1);
-		}
+                                ctx->cmd_args.volfile_id);
+                        errno = EINVAL;
+                        glfs_init_done (fs, -1);
+                }
 
-		break;
+                break;
 	default:
 		break;
 	}
diff --git a/api/src/glfs.h b/api/src/glfs.h
index 4344df24dc..8f1d09d109 100644
--- a/api/src/glfs.h
+++ b/api/src/glfs.h
@@ -285,6 +285,38 @@ int glfs_fini (glfs_t *fs) __THROW;
 
 ssize_t glfs_get_volfile (glfs_t *fs, void *buf, size_t len) __THROW;
 
+
+/*
+  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
  *