IOCTL-XFS-INUMBERS(2)

NAME
ioctl_xfs_inumbers - query allocation information for groups of XFS inodes

SYNOPSIS
#include <xfs/xfs_fs.h>

int ioctl(int fd, XFS_IOC_INUMBERS, struct xfs_inumbers_req *arg);

DESCRIPTION
Query inode allocation information for groups of XFS inodes. This ioctl uses struct xfs_inumbers_req to set up a bulk transfer from the kernel:

struct xfs_inumbers_req {
	struct xfs_bulk_ireq    hdr;
	struct xfs_inumbers     inumbers[];
};

See below for the xfs_inumbers structure definition.

struct xfs_bulk_ireq {
	uint64_t                ino;
	uint32_t                flags;
	uint32_t                icount;
	uint32_t                ocount;
	uint32_t                agno;
	uint64_t                reserved[5];
};

hdr describes the information to query. The layout and behavior are documented in the ioctl_xfs_bulkstat(2) manpage and will not be discussed further here.

inumbers is an array of struct xfs_inumbers which is described below. The array must have at least icount elements.

struct xfs_inumbers {
	uint64_t                xi_startino;
	uint64_t                xi_allocmask;
	uint8_t                 xi_alloccount;
	uint8_t                 xi_version;
	uint8_t                 xi_padding[6];
};

This structure describes inode usage information for a group of 64 consecutive inode numbers.

xi_startino is the first inode number of this group.

xi_allocmask is a bitmask telling which inodes in this group are allocated. To clarify, bit N is set if inode xi_startino+N is allocated.

xi_alloccount is the number of inodes in this group that are allocated. This should be equal to popcnt(xi_allocmask).

xi_version is the version of this data structure. This will be set to XFS_INUMBERS_VERSION_V5 by the kernel.

xi_padding[6] is zeroed.

RETURN VALUE
On error, -1 is returned, and errno is set to indicate the error.

ERRORS
Error codes can be one of, but are not limited to, the following:

EFAULT
    The kernel was not able to copy into the userspace buffer.

EFSBADCRC
    Metadata checksum validation failed while performing the query.

EFSCORRUPTED
    Metadata corruption was encountered while performing the query.

EINVAL
    One of the arguments was not valid.

EIO An I/O error was encountered while performing the query.

ENOMEM
    There was insufficient memory to perform the query.

CONFORMING TO
This API is specific to XFS filesystem on the Linux kernel.

SEE ALSO
ioctl(2), ioctl_xfs_bulkstat(2).