cephfs/admin: Add API to fetch volume info

Signed-off-by: Anoop C S <anoopcs@cryptolab.net>

cephfs/admin/volume_info.go

@@ -0,0 +1,48 @@
+//go:build !(nautilus || octopus) && ceph_preview
+// +build !nautilus,!octopus,ceph_preview
+
+package admin
+
+// PoolInfo reports various properties of a pool.
+type PoolInfo struct {
+	Available int    `json:"avail"`
+	Name      string `json:"name"`
+	Used      int    `json:"used"`
+}
+
+// PoolType indicates the type of pool related to a volume.
+type PoolType struct {
+	DataPool     []PoolInfo `json:"data"`
+	MetadataPool []PoolInfo `json:"metadata"`
+}
+
+// VolInfo holds various informational values about a volume.
+type VolInfo struct {
+	MonAddrs          []string `json:"mon_addrs"`
+	PendingSubvolDels int      `json:"pending_subvolume_deletions"`
+	Pools             PoolType `json:"pools"`
+	UsedSize          int      `json:"used_size"`
+}
+
+func parseVolumeInfo(res response) (*VolInfo, error) {
+	var info VolInfo
+	if err := res.NoStatus().Unmarshal(&info).End(); err != nil {
+		return nil, err
+	}
+	return &info, nil
+}
+
+// FetchVolumeInfo fetches the information of a CephFS volume.
+//
+// Similar To:
+//
+//	ceph fs volume info <vol_name>
+func (fsa *FSAdmin) FetchVolumeInfo(volume string) (*VolInfo, error) {
+	m := map[string]string{
+		"prefix":   "fs volume info",
+		"vol_name": volume,
+		"format":   "json",
+	}
+
+	return parseVolumeInfo(fsa.marshalMgrCommand(m))
+}