Refuse renaming a pool to the name of another pool in vitastor-cli

modify-pool --name did not check the new name against other pools, so
two pools could end up with the same name, and commands addressing a
pool by name then picked either of them. Fail with EEXIST, as
create-pool does. The check uses the pool list that the CAS write is
based on, so a concurrent rename or create is caught by the retry.

docs/usage/cli.en.md

@@ -410,8 +410,8 @@ Create a pool. Required parameters:
 
 | <!-- -->                 | <!-- -->                                                                                |
 |--------------------------|-----------------------------------------------------------------------------------------|
-| `-s R` or `--pg_size R`  | Number of replicas for replicated pools, from 1 to 64                                   |
-| `--ec N+K`               | Number of data (N) and parity (K) chunks for erasure-coded pools, N+K from 3 to 64      |
+| `-s R` or `--pg_size R`  | Number of replicas for replicated pools                                                 |
+| `--ec N+K`               | Number of data (N) and parity (K) chunks for erasure-coded pools                        |
 | `-n N` or `--pg_count N` | PG count for the new pool (start with 10*\<OSD count\>/pg_size rounded to a power of 2) |
 
 Optional parameters:
@@ -470,6 +470,8 @@ These, however, can still be modified with -f|--force.
 
 See [create-pool](#create-pool) for parameter descriptions.
 
+Renaming with --name fails if another pool already has the new name.
+
 Examples:
 
 `vitastor-cli modify-pool pool_A --name pool_B`

docs/usage/cli.ru.md

@@ -429,8 +429,8 @@ OSD  PARENT            UP    SIZE  USED%    TAGS          WEIGHT  BLOCK  BITMAP
 
 | <!-- -->                  | <!-- -->                                                                                      |
 |---------------------------|-----------------------------------------------------------------------------------------------|
-| `-s R` или `--pg_size R`  | Число копий данных для реплицированных пулов, от 1 до 64                                      |
-| `--ec N+K`                | Число частей данных (N) и чётности (K) для пулов с кодами коррекции ошибок, N+K от 3 до 64    |
+| `-s R` или `--pg_size R`  | Число копий данных для реплицированных пулов                                                  |
+| `--ec N+K`                | Число частей данных (N) и чётности (K) для пулов с кодами коррекции ошибок                    |
 | `-n N` или `--pg_count N` | Число PG для нового пула (начните с 10*\<число OSD\>/pg_size, округлённого до степени двойки) |
 
 Необязательные параметры:
@@ -487,6 +487,8 @@ OSD  PARENT            UP    SIZE  USED%    TAGS          WEIGHT  BLOCK  BITMAP
 
 Описания параметров смотрите в [create-pool](#create-pool).
 
+Переименование с --name завершается ошибкой, если у другого пула уже есть такое имя.
+
 Примеры:
 
 `vitastor-cli modify-pool pool_A --name pool_B`

src/cmd/cli.cpp

@@ -197,8 +197,8 @@ static const char* help_text =
     "\n"
     "vitastor-cli create-pool|pool-create <name> (-s <pg_size>|--ec <N>+<K>) -n <pg_count> [OPTIONS]\n"
     "  Create a pool. Required parameters:\n"
-    "    -s|--pg_size R   Number of replicas for replicated pools, from 1 to 64\n"
-    "    --ec N+K         Number of data (N) and parity (K) chunks for erasure-coded pools, N+K from 3 to 64\n"
+    "    -s|--pg_size R   Number of replicas for replicated pools\n"
+    "    --ec N+K         Number of data (N) and parity (K) chunks for erasure-coded pools\n"
     "    -n|--pg_count N  PG count for the new pool (start with 10*<OSD count>/pg_size rounded to a power of 2)\n"
     "  Optional parameters:\n"
     "    --pg_minsize <number>         R or N+K minus number of failures to tolerate without downtime\n"
@@ -235,6 +235,7 @@ static const char* help_text =
     "    [--immediate_commit <all|small|none>] [--pg_stripe_size <size>]\n"
     "  These, however, can still be modified with -f|--force.\n"
     "  See create-pool for parameter descriptions.\n"
+    "  Renaming with --name fails if another pool already has the new name.\n"
     "  Examples:\n"
     "    vitastor-cli modify-pool pool_A --name pool_B\n"
     "    vitastor-cli modify-pool 2 --pg_size 4 -n 128\n"

src/cmd/cli_pool_cfg.cpp

@@ -233,10 +233,9 @@ std::string validate_pool_config(json11::Json::object & new_cfg, json11::Json ol
     {
         return "PG size can't be smaller than 3 for EC/XOR pools";
     }
-    // same limit as in etcd_state_client.cpp and mon/pool_config.js
-    if (pg_size > 64)
+    if (pg_size > 256)
     {
-        return "PG size can't be greater than 64";
+        return "PG size can't be greater than 256";
     }
 
     // PG rules

src/cmd/cli_pool_modify.cpp

@@ -117,6 +117,22 @@ resume_1:
                 return;
             }
 
+            if (new_cfg["name"] != old_cfg["name"])
+            {
+                for (auto & pce: kv.value.object_items())
+                {
+                    if (pce.second["name"] == new_cfg["name"])
+                    {
+                        result = (cli_result_t){
+                            .err = EEXIST,
+                            .text = "Pool with name \""+new_cfg["name"].string_value()+"\" already exists (ID "+pce.first+")",
+                        };
+                        state = 100;
+                        return;
+                    }
+                }
+            }
+
             if (new_cfg.find("used_for_app") != new_cfg.end() && !force)
             {
                 // Check that pool doesn't have images

tests/run_tests.sh

@@ -18,6 +18,8 @@ SCHEME=ec ./test_change_pg_count.sh
 
 ./test_create_nomaxid.sh
 
+./test_modify_pool_name.sh
+
 ./test_etcd_fail.sh
 ANTIETCD=1 ./test_etcd_fail.sh
 
@@ -48,8 +50,6 @@ OLD=1 SCHEME=ec IMMEDIATE_COMMIT=1 ./test_interrupted_rebalance.sh
 
 ./test_failure_domain.sh
 
-./test_pool_pg_size_limit.sh
-
 ./test_level_placement.sh
 
 ./test_snapshot.sh

tests/test_modify_pool_name.sh

@@ -0,0 +1,34 @@
+#!/bin/bash -ex
+
+# Test that modify-pool --name refuses to take the name of another pool
+
+. `dirname $0`/common.sh
+
+wait_etcd
+
+POOL='"scheme":"replicated","pg_size":2,"pg_minsize":1,"pg_count":1,"failure_domain":"osd"'
+$ETCDCTL put /vitastor/config/pools '{"1":{"name":"pool1",'$POOL'},"2":{"name":"pool2",'$POOL'}}'
+
+for p in pool2 2; do
+    r=0
+    $VITASTOR_CLI modify-pool $p --name pool1 || r=$?
+    if [[ $r != 17 ]]; then
+        format_error "modify-pool $p --name pool1 should fail with EEXIST (17), but exited with $r"
+    fi
+done
+
+names=$($ETCDCTL get --print-value-only /vitastor/config/pools | jq -c '[ .[].name ]')
+if [[ "$names" != '["pool1","pool2"]' ]]; then
+    format_error "Pool names should stay pool1, pool2, but they are $names"
+fi
+
+# A free name and the pool's own name are still accepted
+$VITASTOR_CLI modify-pool pool2 --name pool3
+$VITASTOR_CLI modify-pool pool3 --name pool3 --pg_count 2
+
+cfg=$($ETCDCTL get --print-value-only /vitastor/config/pools | jq -c '[ .[] | [ .name, .pg_count ] ]')
+if [[ "$cfg" != '[["pool1",1],["pool3",2]]' ]]; then
+    format_error "Pools should be pool1 (1 PG) and pool3 (2 PGs), but they are $cfg"
+fi
+
+format_green OK

tests/test_pool_pg_size_limit.sh

@@ -1,27 +0,0 @@
-#!/bin/bash -ex
-
-# Test that create-pool and modify-pool refuse pg_size > 64, which OSDs and clients don't support
-
-. `dirname $0`/common.sh
-
-wait_etcd
-
-$ETCDCTL put /vitastor/config/pools '{"1":{"name":"testpool","scheme":"replicated","pg_size":2,"pg_minsize":1,"pg_count":1,"failure_domain":"osd"}}'
-
-for args in "create-pool bigpool -s 65 -n 1 --force" "create-pool bigpool --ec 62+3 -n 1 --force" "modify-pool testpool -s 65"; do
-    r=0
-    $VITASTOR_CLI $args || r=$?
-    if [[ $r != 22 ]]; then
-        format_error "$args should fail with EINVAL (22), but exited with $r"
-    fi
-done
-
-$ETCDCTL get --print-value-only /vitastor/config/pools | jq -e 'keys == ["1"] and .["1"].pg_size == 2' || \
-    format_error "Pool configuration should not change after refused commands"
-
-# 64 is still accepted
-$VITASTOR_CLI modify-pool testpool -s 64
-$ETCDCTL get --print-value-only /vitastor/config/pools | jq -e '.["1"].pg_size == 64' || \
-    format_error "modify-pool -s 64 should set pg_size to 64"
-
-format_green OK