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>

1 files changed, 248 insertions, 2 deletions

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;
 	}