reload: add ability to reload a single block volume

Problem:
-------
Right now, if any block volume is failed to load as part of service bringup
or node reboot, may be because of an issue from the backend, then there is
no way to reload that single block volume, we need to reload/restart all the\
block volumes present in the node just to load one block volume, this interrupts
ongoing  I/O (via this path) for all the volumes hosted within the node.

Solution:
--------
Add ability to reload a single block volume without touching other block volumes
in the node.

$ gluster-block help
usage:
  gluster-block [timeout <seconds>] <command> <volname[/blockname]> [<args>] [--json*]

commands:
[...]
  reload <volname/blockname>
        reload a block device.
[...]

Reviewed-by: Xiubo Li <[email protected]>
Signed-off-by: Prasanna Kumar Kalever <[email protected]>

cli/gluster-block.c

@@ -23,6 +23,7 @@
                                 "<HOST1[,HOST2,...]> [size] [--json*]"
 # define  GB_DELETE_HELP_STR  "gluster-block delete <volname/blockname> "      \
                                 "[unlink-storage <yes|no>] [force] [--json*]"
+# define  GB_RELOAD_HELP_STR  "gluster-block reload <volname/blockname> [--json*]"
 # define  GB_MODIFY_HELP_STR  "gluster-block modify <volname/blockname> "      \
                                 "[auth <enable|disable>] [size <size> "       \
                                 "[force]] [--json*]"
@@ -57,7 +58,8 @@ typedef enum clioperations {
   MODIFY_CLI = 5,
   MODIFY_SIZE_CLI = 6,
   REPLACE_CLI = 7,
-  GENCONF_CLI = 8
+  GENCONF_CLI = 8,
+  RELOAD_CLI = 9
 } clioperations;
 
 
@@ -104,6 +106,7 @@ glusterBlockCliRPC_1(void *cobj, clioperations opt)
   struct sockaddr_un saun = {0,};
   blockCreateCli *create_obj;
   blockDeleteCli *delete_obj;
+  blockReloadCli *reload_obj;
   blockInfoCli *info_obj;
   blockListCli *list_obj;
   blockModifyCli *modify_obj;
@@ -193,6 +196,15 @@ glusterBlockCliRPC_1(void *cobj, clioperations opt)
       goto out;
     }
     break;
+  case RELOAD_CLI:
+    reload_obj = cobj;
+    if (block_reload_cli_1(reload_obj, &reply, clnt) != RPC_SUCCESS) {
+      LOG("cli", GB_LOG_ERROR, "%s block %s reload on volume %s failed",
+          clnt_sperror(clnt, "block_reload_cli_1"),
+          reload_obj->block_name, reload_obj->volume);
+      goto out;
+    }
+    break;
   case INFO_CLI:
     info_obj = cobj;
     if (block_info_cli_1(info_obj, &reply, clnt) != RPC_SUCCESS) {
@@ -318,6 +330,9 @@ glusterBlockHelp(void)
       "  replace <volname/blockname> <old-node> <new-node> [force]\n"
       "        replace operations.\n"
       "\n"
+      "  reload <volname/blockname>\n"
+      "        reload a block device.\n"
+      "\n"
       "  genconfig <volname[,volume2,volume3,...]> enable-tpg <host>\n"
       "        generate the block volumes target configuration.\n"
       "\n"
@@ -896,6 +911,35 @@ glusterBlockDelete(int argcount, char **options, int json)
   return ret;
 }
 
+static int
+glusterBlockReload(int argcount, char **options, int json)
+{
+  blockReloadCli robj = {{0},};
+  int ret = -1;
+
+
+  GB_ARGCHECK_OR_RETURN(argcount, 2, "reload", GB_RELOAD_HELP_STR);
+  robj.json_resp = json;
+
+  if (glusterBlockParseVolumeBlock (options[1], robj.volume, robj.block_name,
+                                    sizeof(robj.volume), sizeof(robj.block_name),
+                                    GB_RELOAD_HELP_STR, "reload")) {
+    goto out;
+  }
+
+  getCommandString(&robj.cmd, argcount, options);
+
+  ret = glusterBlockCliRPC_1(&robj, RELOAD_CLI);
+  if (ret) {
+    LOG("cli", GB_LOG_ERROR,
+        "failed reload of block %s on volume %s",
+        robj.block_name, robj.volume);
+  }
+
+ out:
+
+  return ret;
+}
 
 static int
 glusterBlockInfo(int argcount, char **options, int json)
@@ -1089,6 +1133,13 @@ glusterBlockParseArgs(int count, char **options, size_t opt, int json)
       }
       goto out;
 
+    case GB_CLI_RELOAD:
+      ret = glusterBlockReload(count, options, json);
+      if (ret) {
+        LOG("cli", GB_LOG_ERROR, FAILED_RELOAD);
+      }
+      goto out;
+
     case GB_CLI_HELP:
     case GB_CLI_HYPHEN_HELP:
     case GB_CLI_USAGE:

rpc/Makefile.am

@@ -5,7 +5,7 @@ noinst_LTLIBRARIES = libgbrpc.la
 libgbrpc_la_SOURCES = block_svc_routines.c block_info.c block_list.c           \
                       block_create.c block_delete.c block_modify.c             \
                       block_replace.c block_version.c block_genconfig.c        \
-                      block_common.h glfs-operations.c
+                      block_reload.c block_common.h glfs-operations.c
 
 noinst_HEADERS = glfs-operations.h
 

rpc/block_common.h

@@ -31,6 +31,8 @@
 # define   GB_TGCLI_GLFS        "targetcli " GB_TGCLI_GLFS_PATH
 # define   GB_TGCLI_CHECK       GB_TGCLI_GLFS " ls | grep ' %s ' | grep '/%s ' > " DEVNULLPATH
 # define   GB_TGCLI_ISCSI_PATH  "/iscsi"
+# define   GB_TGCLI_ISCSI       "targetcli " GB_TGCLI_ISCSI_PATH
+# define   GB_TGCLI_ISCSI_CHECK GB_TGCLI_ISCSI " ls | grep ' %s%s ' > " DEVNULLPATH
 # define   GB_TGCLI_GLFS_SAVE   GB_TGCLI_GLFS_PATH "/%s saveconfig"
 # define   GB_TGCLI_ATTRIBUTES  "generate_node_acls=1 demo_mode_write_protect=0"
 # define   GB_TGCLI_IQN_PREFIX  "iqn.2016-12.org.gluster-block:"
@@ -64,7 +66,8 @@ typedef enum operations {
   LIST_SRV,
   INFO_SRV,
   VERSION_SRV,
-  GENCONFIG_SRV
+  GENCONFIG_SRV,
+  RELOAD_SRV
 } operations;