vstart.sh: only skip fs volume create when there's no mgr to run it

The mgr volumes module handles fs volume ls/create, not the monitor, so
without a mgr (CEPH_NUM_MGR=0) the "wait for volume module to load" loop
spun forever. Open-coding fs new unconditionally, my first attempt,
changed pool creation for every vstart user and dropped the wait, so
cephfs tests calling `fs volume ...` right after vstart.sh returns could
race a module still mid-load.

create_fs_volume() branches on CEPH_NUM_MGR instead. With a mgr it still
calls fs volume ls/create. Without one it runs the plain mon commands fs
volume create wraps: osd pool create cephfs.<name>.{meta,data}, then fs
new <name> <meta> <data>. The wait stays at its one call site above the
per-filesystem loop, so it runs once regardless of CEPH_NUM_FS, not once
per filesystem.

Verified against a local vstart: mgr present, fs volume ls polls once
then creates CEPH_NUM_FS=2 filesystems with no repeated poll;
CEPH_NUM_MGR=0, no poll, fs new creates 'a' directly, HEALTH_OK.

Signed-off-by: Kefu Chai <k.chai@proxmox.com>

src/vstart.sh

@@ -1482,6 +1482,19 @@ EOF
     fi
 }
 
+create_fs_volume() {
+    local name=$1
+    if [ "$CEPH_NUM_MGR" -gt 0 ]; then
+        ceph_adm fs volume create ${name}
+    else
+        local meta_pool="cephfs.${name}.meta"
+        local data_pool="cephfs.${name}.data"
+        ceph_adm osd pool create "$meta_pool"
+        ceph_adm osd pool create "$data_pool" --bulk
+        ceph_adm fs new ${name} "$meta_pool" "$data_pool"
+    fi
+}
+
 start_mds() {
     local mds=0
     for name in a b c d e f g h i j k l m n o p
@@ -1532,12 +1545,15 @@ EOF
                 ceph_adm fs flag set enable_multiple true --yes-i-really-mean-it
             fi
 
-	    # wait for volume module to load
-	    while ! ceph_adm fs volume ls ; do sleep 1 ; done
+            if [ "$CEPH_NUM_MGR" -gt 0 ]; then
+                # wait for volume module to load
+                while ! ceph_adm fs volume ls ; do sleep 1 ; done
+            fi
+
             local fs=0
             for name in a b c d e f g h i j k l m n o p
             do
-                ceph_adm fs volume create ${name}
+                create_fs_volume ${name}
                 ceph_adm fs authorize ${name} "client.fs_${name}" / rwp >> "$keyring_fn"
                 fs=$(($fs + 1))
                 [ $fs -eq $CEPH_NUM_FS ] && break