ioctl_fslabel

NAME

ioctl_fslabel - get or set a filesystem label

LIBRARY

Standard C library (libc, -lc)

SYNOPSIS

#include <linux/fs.h>       /* Definition of *FSLABEL* constants */
#include <sys/ioctl.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

Possible errors 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.

STANDARDS

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.

SEE ALSO

ioctl(2), blkid(8)