Seed fsName to ceph-csi's node plugin

This option is now mandatory to use when there
are multiple CephFS file systems in the ceph
cluster. Without this, ceph won't be able to find
the (sub)volume to mount.

Fixes #2992
Fixes #2986

Author: gouthampacha

pkg/csi/manila/nodeserver.go

@@ -133,6 +133,7 @@ func (ns *nodeServer) buildVolumeContext(ctx context.Context, volID volumeID, sh
 	sa := getShareAdapter(ns.d.shareProto)
 	opts := &shareadapters.VolumeContextArgs{
 		Locations: availableExportLocations,
+		Share:     share,
 		Options:   shareOpts,
 	}
 	volumeContext, err = sa.BuildVolumeContext(opts)

pkg/csi/manila/shareadapters/cephfs.go

@@ -19,6 +19,7 @@ package shareadapters
 import (
 	"context"
 	"fmt"
+	"strings"
 	"time"
 
 	"github.com/gophercloud/gophercloud/v2"
@@ -133,9 +134,44 @@ func (Cephfs) BuildVolumeContext(args *VolumeContextArgs) (volumeContext map[str
 		volCtx["fuseMountOptions"] = args.Options.CephfsFuseMountOptions
 	}
 
+	// Extract fs_name from __mount_options metadata if available
+	if fsName := extractFsNameFromMountOptions(args.Share); fsName != "" {
+		volCtx["fsName"] = fsName
+		klog.V(4).Infof("Found fs_name in share metadata: %s", fsName)
+	}
+
 	return volCtx, err
 }
 
+// extractFsNameFromMountOptions extracts the fs from __mount_options metadata
+// The __mount_options metadata contains mount options including fs for CephFS
+func extractFsNameFromMountOptions(share *shares.Share) string {
+	if share == nil || share.Metadata == nil {
+		return ""
+	}
+
+	mountOptions, exists := share.Metadata["__mount_options"]
+	if !exists {
+		klog.V(4).Infof("No __mount_options metadata found in share %s", share.ID)
+		return ""
+	}
+
+	// Parse mount options to extract fs
+	// Mount options are typically comma-separated key=value pairs
+	// Example: "fs=myfs,other_option=value"
+	options := strings.Split(mountOptions, ",")
+	for _, option := range options {
+		option = strings.TrimSpace(option)
+		if strings.HasPrefix(option, "fs=") {
+			fsName := strings.TrimPrefix(option, "fs=")
+			return strings.TrimSpace(fsName)
+		}
+	}
+
+	klog.V(4).Infof("No fs found in __mount_options metadata for share %s: %s", share.ID, mountOptions)
+	return ""
+}
+
 func (Cephfs) BuildNodeStageSecret(args *SecretArgs) (secret map[string]string, err error) {
 	return map[string]string{
 		"userID":  args.AccessRight.AccessTo,

pkg/csi/manila/shareadapters/shareadapter.go

@@ -35,6 +35,9 @@ type VolumeContextArgs struct {
 	// an export location when building a volume context.
 	Locations []shares.ExportLocation
 
+	// Share object containing metadata and other share information
+	Share *shares.Share
+
 	Options *options.NodeVolumeContext
 }