journal: implementation for listOmapVals

Added a implementation for the listOmapVals
which list the object keys and values from
the rados omap.

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

internal/journal/omap.go

@@ -19,6 +19,7 @@ package journal
 import (
 	"context"
 	"errors"
+	"fmt"
 
 	"github.com/ceph/ceph-csi/internal/util"
 	"github.com/ceph/ceph-csi/internal/util/log"
@@ -79,7 +80,7 @@ func getOMapValues(
 			log.ErrorLog(ctx, "omap not found (pool=%q, namespace=%q, name=%q): %v",
 				poolName, namespace, oid, err)
 
-			return nil, util.JoinErrors(util.ErrKeyNotFound, err)
+			return nil, fmt.Errorf("%w: %w", util.ErrKeyNotFound, err)
 		}
 
 		return nil, err
@@ -168,3 +169,57 @@ func omapPoolError(err error) error {
 
 	return err
 }
+
+// listOMapValues fetches all omap values for a given oid, prefix, and namespace.
+func listOMapValues(
+	ctx context.Context,
+	conn *Connection,
+	poolName, namespace, oid, prefix string,
+) (map[string]string, error) {
+	// fetch and configure the rados ioctx
+	ioctx, err := conn.conn.GetIoctx(poolName)
+	if err != nil {
+		return nil, omapPoolError(err)
+	}
+	defer ioctx.Destroy()
+
+	if namespace != "" {
+		ioctx.SetNamespace(namespace)
+	}
+
+	results := map[string]string{}
+
+	numKeys := uint64(0)
+	startAfter := ""
+	for {
+		prevNumKeys := numKeys
+		err = ioctx.ListOmapValues(
+			oid, startAfter, prefix, chunkSize,
+			func(key string, value []byte) {
+				numKeys++
+				startAfter = key
+				results[key] = string(value)
+			},
+		)
+		// if we hit an error, or no new keys were seen, exit the loop
+		if err != nil || numKeys == prevNumKeys {
+			break
+		}
+	}
+
+	if err != nil {
+		if errors.Is(err, rados.ErrNotFound) {
+			log.ErrorLog(ctx, "omap not found (pool=%q, namespace=%q, name=%q): %v",
+				poolName, namespace, oid, err)
+
+			return nil, fmt.Errorf("%w: %w", util.ErrKeyNotFound, err)
+		}
+
+		return nil, err
+	}
+
+	log.DebugLog(ctx, "got omap values: (pool=%q, namespace=%q, name=%q): %+v",
+		poolName, namespace, oid, results)
+
+	return results, nil
+}