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Man page of IOCTL-XFS-AG-GEOMETRY
IOCTL-XFS-AG-GEOMETRY
Section: System Calls (2)
Updated: 2019-04-11
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NAME
ioctl_xfs_ag_geometry - query XFS allocation group geometry information
SYNOPSIS
#include <xfs/xfs_fs.h>
int ioctl(int dest_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_reserved32;
uint64_t ag_reserved[12];
};
The field
ag_number
indicates the number of allocation group that the caller wishes to learn about.
The fields
ag_length and ag_freeblks
are set to the number of blocks and the number of free blocks in the allocation
group, in units of filesystem blocks.
The field
ag_icount
is set to the number of inode records allocated in this allocation group.
The field
ag_ifree
is set to the number of unused inode records (of the space allocated) in this
allocation group.
The fields
ag_reserved and ag_reserved32
will be set to zero.
The fields
ag_sick and ag_checked
indicate the relative health of various allocation group metadata:
- •
-
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.
- •
-
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.
- •
-
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
ioctl(2)
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- CONFORMING TO
-
- SEE ALSO
-
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Time: 14:54:29 GMT, April 11, 2019