Module label 

Filesystem label: reading and writing the human-readable name of a filesystem

The label is a short null-terminated string (up to 255 bytes) stored in the superblock. It is visible in /sys/fs/btrfs/<uuid>/label and is used by tools like blkid to identify the filesystem. Labels are stored as CString values to preserve the kernel’s null-termination contract.

Functions

label_get

Read the label of the btrfs filesystem referred to by fd.

label_set

Set the label of the btrfs filesystem referred to by fd.