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package btrfs
import (
"encoding/binary"
"fmt"
"os"
)
func lookupUUIDSubvolItem(f *os.File, uuid UUID) (objectID, error) {
return uuidTreeLookupAny(f, uuid, uuidKeySubvol)
}
func lookupUUIDReceivedSubvolItem(f *os.File, uuid UUID) (objectID, error) {
return uuidTreeLookupAny(f, uuid, uuidKeyReceivedSubvol)
}
func (id UUID) toKey() (objID objectID, off uint64) {
objID = objectID(binary.LittleEndian.Uint64(id[:8]))
off = binary.LittleEndian.Uint64(id[8:16])
return
}
// uuidTreeLookupAny searches uuid tree for a given uuid in specified field.
// It returns ErrNotFound if object was not found.
func uuidTreeLookupAny(f *os.File, uuid UUID, typ treeKeyType) (objectID, error) {
objId, off := uuid.toKey()
args := btrfs_ioctl_search_key{
tree_id: uuidTreeObjectid,
min_objectid: objId,
max_objectid: objId,
min_type: typ,
max_type: typ,
min_offset: off,
max_offset: off,
max_transid: maxUint64,
nr_items: 1,
}
res, err := treeSearchRaw(f, args)
if err != nil {
return 0, err
} else if len(res) < 1 {
return 0, ErrNotFound
}
out := res[0]
if len(out.Data) != 8 {
return 0, fmt.Errorf("btrfs: uuid item with illegal size %d", len(out.Data))
}
return objectID(binary.LittleEndian.Uint64(out.Data)), nil
}
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