glusterd/shared_storage: Provide a volume set option to create and mount the shared storage

     Backport of http://review.gluster.org/#/c/10793/

Introducing a global volume set option(cluster.enable-shared-storage)
which helps create and set-up the shared storage meta volume.

gluster volume set all cluster.enable-shared-storage enable

On enabling this option, the system analyzes the number of peers
in the cluster, which are currently connected, and chooses three
such peers(including the node the command is issued from). From these
peers a volume(gluster_shared_storage) is created. Depending on the
number of peers available the volume is either a replica 3
volume(if there are 3 connected peers),  or a replica 2 volume(if there
are 2 connected peers). "/var/run/gluster/ss_brick" serves as the
brick path on each node for the shared storage volume. We also mount
the shared storage at "/var/run/gluster/shared_storage" on all the nodes
in the cluster as part of enabling this option. If there is only one node
in the cluster,  or only one node is up then the command will fail

Once the volume is created, and mounted the maintainance of the
volume like adding-bricks, removing bricks etc., is expected to
be the onus of the user.

On disabling the option, we provide the user a warning, and on
affirmation from the user we stop the shared storage volume, and unmount
it from all the nodes in the cluster.

gluster volume set all cluster.enable-shared-storage disable

Change-Id: Idd92d67b93f444244f99ede9f634ef18d2945dbc
BUG: 1228181
Signed-off-by: Avra Sengupta <asengupt@redhat.com>
Reviewed-on: http://review.gluster.org/11086
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Rajesh Joseph <rjoseph@redhat.com>
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>

1 files changed, 190 insertions, 6 deletions

diff --git a/xlators/mgmt/glusterd/src/glusterd-op-sm.c b/xlators/mgmt/glusterd/src/glusterd-op-sm.c
index 326968ea6b8..9b9684e59a1 100644
--- a/xlators/mgmt/glusterd/src/glusterd-op-sm.c
+++ b/xlators/mgmt/glusterd/src/glusterd-op-sm.c
@@ -55,11 +55,36 @@
 #include <signal.h>
 #include <sys/wait.h>
 
+extern char ss_brick_path[PATH_MAX];
+extern char local_node_hostname[PATH_MAX];
+static int
+glusterd_set_shared_storage (dict_t *dict, char *key, char *value,
+                             char **op_errstr);
+
+/* Valid options for all volumes to be listed in the *
+ * valid_all_vol_opts table. To add newer options to *
+ * all volumes, we can just add more entries to this *
+ * table                                             *
+ */
+glusterd_all_vol_opts   valid_all_vol_opts[] = {
+        { GLUSTERD_QUORUM_RATIO_KEY },
+        { GLUSTERD_SHARED_STORAGE_KEY },
+        { NULL },
+};
+
 #define ALL_VOLUME_OPTION_CHECK(volname, key, ret, op_errstr, label)           \
         do {                                                                   \
-                gf_boolean_t    _all = !strcmp ("all", volname);               \
-                gf_boolean_t    _ratio = !strcmp (key,                         \
-                                                  GLUSTERD_QUORUM_RATIO_KEY);  \
+                gf_boolean_t    _all   = !strcmp ("all", volname);             \
+                gf_boolean_t    _ratio = _gf_false;                            \
+                int32_t         i      = 0;                                    \
+                                                                               \
+                for (i = 0; valid_all_vol_opts[i].option; i++) {               \
+                        if (!strcmp (key, valid_all_vol_opts[i].option)) {     \
+                                _ratio = _gf_true;                             \
+                                break;                                         \
+                        }                                                      \
+                }                                                              \
+                                                                               \
                 if (_all && !_ratio) {                                         \
                         ret = -1;                                              \
                         *op_errstr = gf_strdup ("Not a valid option for all "  \
@@ -682,6 +707,71 @@ out:
 }
 
 static int
+glusterd_validate_shared_storage (char *key, char *value, char *errstr)
+{
+        int32_t       ret      = -1;
+        int32_t       exists   = -1;
+        int32_t       count    = -1;
+        xlator_t     *this     = NULL;
+
+        this = THIS;
+        GF_VALIDATE_OR_GOTO ("glusterd", this, out);
+        GF_VALIDATE_OR_GOTO (this->name, key, out);
+        GF_VALIDATE_OR_GOTO (this->name, value, out);
+        GF_VALIDATE_OR_GOTO (this->name, errstr, out);
+
+        ret = 0;
+
+        if (strcmp (key, GLUSTERD_SHARED_STORAGE_KEY)) {
+                goto out;
+        }
+
+        if ((strcmp (value, "enable")) &&
+            (strcmp (value, "disable"))) {
+                snprintf (errstr, PATH_MAX,
+                          "Invalid option(%s). Valid options "
+                          "are 'enable' and 'disable'", value);
+                gf_log (this->name, GF_LOG_ERROR, "%s", errstr);
+                ret = -1;
+                goto out;
+        }
+
+        if (strcmp (value, "enable")) {
+                goto out;
+        }
+
+        exists = glusterd_check_volume_exists (GLUSTER_SHARED_STORAGE);
+        if (exists) {
+                snprintf (errstr, PATH_MAX,
+                          "Shared storage volume("GLUSTER_SHARED_STORAGE
+                          ") already exists.");
+                gf_log (this->name, GF_LOG_ERROR, "%s", errstr);
+                ret = -1;
+                goto out;
+        }
+
+        ret = glusterd_count_connected_peers (&count);
+        if (ret) {
+                snprintf (errstr, PATH_MAX,
+                          "Failed to calculate number of connected peers.");
+                gf_log (this->name, GF_LOG_ERROR, "%s", errstr);
+                goto out;
+        }
+
+        if (count <= 1) {
+                snprintf (errstr, PATH_MAX,
+                          "More than one node should "
+                          "be up/present in the cluster to enable this option");
+                gf_log (this->name, GF_LOG_ERROR, "%s", errstr);
+                ret = -1;
+                goto out;
+        }
+
+out:
+        return ret;
+}
+
+static int
 glusterd_op_stage_set_volume (dict_t *dict, char **op_errstr)
 {
         int                             ret                     = -1;
@@ -696,7 +786,7 @@ glusterd_op_stage_set_volume (dict_t *dict, char **op_errstr)
         int                             trash_path_len          = 0;
         int                             count                   = 0;
         int                             dict_count              = 0;
-        char                            errstr[2048]            = {0, };
+        char                            errstr[PATH_MAX]        = {0, };
         glusterd_volinfo_t              *volinfo                = NULL;
         glusterd_brickinfo_t            *brickinfo              = NULL;
         dict_t                          *val_dict               = NULL;
@@ -1000,6 +1090,14 @@ glusterd_op_stage_set_volume (dict_t *dict, char **op_errstr)
                         }
                 }
 
+                ret = glusterd_validate_shared_storage (key, value, errstr);
+                if (ret) {
+                        gf_log (this->name, GF_LOG_ERROR,
+                                "Failed to validate shared "
+                                "storage volume options");
+                        goto out;
+                }
+
                 if (!strcmp(key, "features.trash-dir") && trash_enabled) {
                         if (strchr (value, '/')) {
                                 snprintf (errstr, sizeof (errstr),
@@ -1918,7 +2016,8 @@ out:
 }
 
 static int
-glusterd_op_set_all_volume_options (xlator_t *this, dict_t *dict)
+glusterd_op_set_all_volume_options (xlator_t *this, dict_t *dict,
+                                    char **op_errstr)
 {
         char            *key            = NULL;
         char            *key_fixed      = NULL;
@@ -1942,6 +2041,7 @@ glusterd_op_set_all_volume_options (xlator_t *this, dict_t *dict)
                         "invalid key,value pair in 'volume set'");
                 goto out;
         }
+
         ret = glusterd_check_option_exists (key, &key_fixed);
         if (ret <= 0) {
                 gf_log (this->name, GF_LOG_ERROR, "Invalid key %s", key);
@@ -1952,6 +2052,13 @@ glusterd_op_set_all_volume_options (xlator_t *this, dict_t *dict)
         if (key_fixed)
                 key = key_fixed;
 
+        ret = glusterd_set_shared_storage (dict, key, value, op_errstr);
+        if (ret) {
+                gf_log (this->name, GF_LOG_ERROR,
+                        "Failed to set shared storage option");
+                goto out;
+        }
+
         /* If the key is cluster.op-version, set conf->op_version to the value
          * if needed and save it.
          */
@@ -2030,6 +2137,82 @@ out:
 }
 
 static int
+glusterd_set_shared_storage (dict_t *dict, char *key, char *value,
+                             char **op_errstr)
+{
+        int32_t       ret                  = -1;
+        int32_t       exists               = -1;
+        int32_t       count                = -1;
+        char          hooks_args[PATH_MAX] = {0, };
+        char          errstr[PATH_MAX]     = {0, };
+        xlator_t     *this                 = NULL;
+
+        this = THIS;
+        GF_VALIDATE_OR_GOTO ("glusterd", this, out);
+        GF_VALIDATE_OR_GOTO (this->name, dict, out);
+        GF_VALIDATE_OR_GOTO (this->name, key, out);
+        GF_VALIDATE_OR_GOTO (this->name, value, out);
+        GF_VALIDATE_OR_GOTO (this->name, op_errstr, out);
+
+        ret = 0;
+
+        if (strcmp (key, GLUSTERD_SHARED_STORAGE_KEY)) {
+                goto out;
+        }
+
+        /* Re-create the brick path so as to be *
+         * able to re-use it                    *
+         */
+        ret = recursive_rmdir (ss_brick_path);
+        if (ret) {
+                snprintf (errstr, PATH_MAX,
+                          "Failed to remove shared "
+                          "storage brick(%s). "
+                          "Reason: %s", ss_brick_path,
+                          strerror (errno));
+                gf_log (this->name, GF_LOG_ERROR, "%s", errstr);
+                ret = -1;
+                goto out;
+        }
+
+        ret = mkdir_p (ss_brick_path, 0777, _gf_true);
+        if (-1 == ret) {
+                snprintf (errstr, PATH_MAX,
+                          "Failed to create shared "
+                          "storage brick(%s). "
+                          "Reason: %s", ss_brick_path,
+                          strerror (errno));
+                gf_log (this->name, GF_LOG_ERROR, "%s", errstr);
+                goto out;
+        }
+
+        if (is_origin_glusterd (dict)) {
+                snprintf(hooks_args, sizeof(hooks_args),
+                         "is_originator=1,local_node_hostname=%s",
+                         local_node_hostname);
+        } else {
+                snprintf(hooks_args, sizeof(hooks_args),
+                         "is_originator=0,local_node_hostname=%s",
+                         local_node_hostname);
+        }
+
+        ret = dict_set_dynstr_with_alloc (dict, "hooks_args", hooks_args);
+        if (ret) {
+                gf_log (this->name, GF_LOG_ERROR, "Failed to set"
+                        " hooks_args in dict.");
+                goto out;
+        }
+
+out:
+        if (ret && strlen(errstr)) {
+                *op_errstr = gf_strdup (errstr);
+        }
+
+        return ret;
+}
+
+
+static int
 glusterd_op_set_volume (dict_t *dict, char **errstr)
 {
         int                                      ret = 0;
@@ -2083,7 +2266,8 @@ glusterd_op_set_volume (dict_t *dict, char **errstr)
         }
 
         if (strcasecmp (volname, "all") == 0) {
-                ret = glusterd_op_set_all_volume_options (this, dict);
+                ret = glusterd_op_set_all_volume_options (this, dict,
+                                                          &op_errstr);
                 goto out;
         }