IOCTL-XFS-SCRUBV-METADATA(2)

NAME
ioctl_xfs_scrubv_metadata - check a lot of XFS filesystem metadata

SYNOPSIS
#include <xfs/xfs_fs.h>

int ioctl(int dest_fd, XFS_IOC_SCRUBV_METADATA, struct xfs_scrub_vec_head *arg);

DESCRIPTION
This XFS ioctl asks the kernel driver to examine several pieces of filesystem metadata for errors or suboptimal metadata. Multiple scrub types can be invoked to target a single filesystem object. See ioctl_xfs_scrub_metadata(2) for a discussion of metadata validation, and documentation of the various XFS_SCRUB_TYPE and XFS_SCRUB_FLAGS values referenced below.

The types and location of the metadata to scrub are conveyed as a vector with a header of the following form:

struct xfs_scrub_vec_head {
	__u64 svh_ino;
	__u32 svh_gen;
	__u32 svh_agno;
	__u32 svh_flags;
	__u16 svh_rest_us;
	__u16 svh_nr;
	__u64 svh_reserved;
	__u64 svh_vectors;
};

The field svh_ino, svh_gen, and svh_agno correspond to the sm_ino, sm_gen, and sm_agno fields of the regular scrub ioctl. Exactly one filesystem object can be specified in a single call. The kernel will proceed with each vector in svh_vectors until progress is no longer possible.

The field svh_rest_us specifies an amount of time to pause between each scrub invocation to give the system a chance to process other requests.

The field svh_nr specifies the number of vectors in the svh_vectors array.

The field svh_vectors is a pointer to an array of struct xfs_scrub_vec structures.

The field svh_reserved must be zero.

Each vector has the following form:

struct xfs_scrub_vec {
	__u32 sv_type;
	__u32 sv_flags;
	__s32 sv_ret;
	__u32 sv_reserved;
};

The fields sv_type and sv_flags indicate the type of metadata to check and the behavioral changes that userspace will permit of the kernel. The sv_flags field will be updated upon completion of the scrub call. See the documentation of XFS_SCRUB_TYPE_* and XFS_SCRUB_[IO]FLAG_* values in ioctl_xfs_scrub_metadata(2) for a detailed description of their purpose.

If a vector's sv_type field is set to the value XFS_SCRUB_TYPE_BARRIER, the kernel will stop processing vectors and return to userspace if a scrubber flags corruption by setting one of the XFS_SCRUB_OFLAG_* values in sv_flags or returns an operation error in sv_ret. Otherwise, the kernel returns only after processing all vectors.

The sv_ret field is set to the return value of the scrub function. See the RETURN VALUE section of the ioctl_xfs_scrub_metadata(2) manual page for more information.

The sv_reserved field must be zero.

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:

EINVAL
    One or more of the arguments specified is invalid.

EINTR
    The operation was interrupted.

ENOMEM
    There was not sufficient memory to perform the scrub or repair operation.

EFAULT
    A memory fault was encountered while reading or writing the vector.

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

NOTES
These operations may block other filesystem operations for a long time. A calling process can stop the operation by being sent a fatal signal, but non-fatal signals are blocked.

SEE ALSO
ioctl(2) ioctl_xfs_scrub_metadata(2) xfs_scrub(8) xfs_repair(8)