NAME

       ioctl_fslabel - get or set a filesystem label

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.

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.

SEE ALSO

       ioctl(2), blkid(8)

COLOPHON

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