Ioctl_fslabel (2) Linux Manual Page

ioctl_fslabel – get or set a filesystem label

Synopsis

#include <sys/ioctl.h>
#include <linux/fs.h>

int ioctl(int fd, FS_IOC_GETFSLABEL, char label[FSLABEL_MAX]);
int ioctl(int fd, FS_IOC_SETFSLABEL, char label[FSLABEL_MAX]);

Description

If a filesystem supports online label manipulation, these ioctl(2) operations can be used to get or set the filesystem label for the filesystem on which fd resides. The FS_IOC_SETFSLABEL operation requires privilege (CAP_SYS_ADMIN).

Return Value

On success zero is returned. On error, -1 is returned, and errno is set to indicate the error.

Errors

Error can include (but are not limited to) the following:

EFAULT: label references an inaccessible memory area.
EINVAL: The specified label exceeds the maximum label length for the filesystem.
ENOTTY: This can appear if the filesystem does not support online label manipulation.
EPERM: The calling process does not have sufficient permissions to set the label.

Versions

These ioctl(2) operations first appeared in Linux 4.18. They were previously known as BTRFS_IOC_GET_FSLABEL and BTRFS_IOC_SET_FSLABEL and were private to Btrfs.

Conforming To

This API is Linux-specific.

Notes

The maximum string length for this interface is FSLABEL_MAX, including the terminating null byte (‘\0’). Filesystems have differing maximum label lengths, which may or may not include the terminating null. The string provided to FS_IOC_SETFSLABEL must always be null-terminated, and the string returned by FS_IOC_GETFSLABEL will always be null-terminated.

Colophon

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ioctl_fslabel (2) Linux Manual Page