ioctl_xfs_inumbers - query allocation information for groups of XFS inodes

NAME SYNOPSIS DESCRIPTION RETURN VALUE ERRORS CONFORMING TO SEE ALSO

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.