Linux repositories inspector

ioctl_xfs_ag_geometry(2)

XFS
2019-08-30

xfslibs-dev

XFS filesystem-specific static libraries and headers

xfsprogs-devel

XFS Filesystem-specific Static Libraries and Headers

xfsprogs

Utilities for managing the XFS filesystem

NAME

ioctl_xfs_ag_geometry - query XFS allocation group geometry information

SYNOPSIS

#include <xfs/xfs_fs.h>
int ioctl(int fd, XFS_IOC_AG_GEOMETRY, struct xfs_ag_geometry *arg);

DESCRIPTION

This XFS ioctl retrieves the geometry information for a given allocation group. The geometry information is conveyed in a structure of the following form:
struct xfs_ag_geometry {
        uint32_t  ag_number;
        uint32_t  ag_length;
        uint32_t  ag_freeblks;
        uint32_t  ag_icount;
        uint32_t  ag_ifree;
        uint32_t  ag_sick;
        uint32_t  ag_checked;
        uint32_t  ag_flags;
        uint64_t  ag_reserved[12];
};
ag_number
The caller must set this field to the index of the allocation group that the caller wishes to learn about.
ag_length
The length of the allocation group is returned in this field, in units of filesystem blocks.
ag_freeblks
The number of free blocks in the allocation group is returned in this field, in units of filesystem blocks.
ag_icount
The number of inode records allocated in this allocation group is returned in this field.
ag_ifree
The number of unused inode records (of the space allocated) in this allocation group is returned in this field.
ag_flags
The caller can set this field to change the operational behavior of the ioctl. Currently no flags are defined, so this field must be zero.
ag_reserved
All reserved fields will be set to zero on return.
The fields ag_sick and ag_checked indicate the relative health of various allocation group metadata:
[bu] If a given sick flag is set in ag_sick, then that piece of metadata has been observed to be damaged. The same bit will be set in ag_checked.
[bu] If a given sick flag is set in ag_checked and is not set in ag_sick, then that piece of metadata has been checked and is not faulty.
[bu] If a given sick flag is not set in ag_checked, then no conclusion can be made.
The following flags apply to these fields:
XFS_AG_GEOM_SICK_SB
Allocation group superblock.
XFS_AG_GEOM_SICK_AGF
Free space header.
XFS_AG_GEOM_SICK_AGFL
Free space reserve list.
XFS_AG_GEOM_SICK_AGI
Inode header.
XFS_AG_GEOM_SICK_BNOBT or XFS_AG_GEOM_SICK_CNTBT
Free space btrees.
XFS_AG_GEOM_SICK_INOBT or XFS_AG_GEOM_SICK_FINOBT
Inode btrees.
XFS_AG_GEOM_SICK_RMAPBT
Reverse mapping btree.
XFS_AG_GEOM_SICK_REFCNTBT
Reference count btree.

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:
EFSBADCRC
Metadata checksum validation failed while performing the query.
EFSCORRUPTED
Metadata corruption was encountered while performing the query.
EINVAL The specified allocation group number is not valid for this filesystem.
EIO An I/O error was encountered while performing the query.

CONFORMING TO

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

SEE ALSO

REFERENCED BY

⇧ Top