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NAME | SYNOPSIS | DESCRIPTION | FILESYSTEM FEATURE FLAGS | XFS METADATA HEALTH REPORTING | RETURN VALUE | ERRORS | CONFORMING TO | SEE ALSO | COLOPHON |
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IOCTL-XFS-FSGEOMETRY(2) System Calls Manual IOCTL-XFS-FSGEOMETRY(2)
ioctl_xfs_fsgeometry - report XFS filesystem layout and features
#include <xfs/xfs_fs.h>
int ioctl(int fd, XFS_IOC_FSGEOMETRY, struct xfs_fsop_geom *arg);
int ioctl(int fd, XFS_IOC_FSGEOMETRY_V4, struct xfs_fsop_geom_v4
*arg);
int ioctl(int fd, XFS_IOC_FSGEOMETRY_V1, struct xfs_fsop_geom_v1
*arg);
Report the details of an XFS filesystem layout, features, and
other descriptive items. This information is conveyed in a
structure of the following form:
struct xfs_fsop_geom {
__u32 blocksize;
__u32 rtextsize;
__u32 agblocks;
__u32 agcount;
__u32 logblocks;
__u32 sectsize;
__u32 inodesize;
__u32 imaxpct;
__u64 datablocks;
__u64 rtblocks;
__u64 rtextents;
__u64 logstart;
unsigned char uuid[16];
__u32 sunit;
__u32 swidth;
__s32 version;
__u32 flags;
__u32 logsectsize;
__u32 rtsectsize;
__u32 dirblocksize;
/* struct xfs_fsop_geom_v1 stops here. */
__u32 logsunit;
/* struct xfs_fsop_geom_v4 stops here. */
__u32 sick;
__u32 checked;
__u64 rgextents;
__u64 rtstart;
__u64 rtreserved;
__u64 reserved[14];
};
blocksize is the size of a fundamental filesystem block, in bytes.
rtextsize is the size of an extent on the realtime volume, in
bytes.
agblocks is the size of an allocation group, in units of
filesystem blocks.
agcount is the number of allocation groups in the filesystem.
logblocks is the size of the log, in units of filesystem blocks.
sectsize is the smallest amount of data that can be written to the
data device atomically, in bytes.
inodesize is the size of an inode record, in bytes.
imaxpct is the maximum percentage of the filesystem that can be
allocated to inode record blocks.
datablocks is the size of the data device, in units of filesystem
blocks.
rtblocks is the size of the realtime device, in units of
filesystem blocks.
rtextents is the number of extents that can be allocated on the
realtime device.
logstart is the start of the log, in units of filesystem blocks.
If the filesystem has an external log, this will be zero.
uuid is the universal unique identifier of the filesystem.
sunit is what the filesystem has been told is the size of a RAID
stripe unit on the underlying data device, in filesystem blocks.
swidth is what the filesystem has been told is the width of a RAID
stripe on the underlying data device, in units of RAID stripe
units.
version is the version of this structure. This value will be
XFS_FSOP_GEOM_VERSION.
flags tell us what features are enabled on the filesystem. Refer
to the section FILESYSTEM FEATURE FLAGS below for more information
about each feature.
logsectsize is the smallest amount of data that can be written to
the log device atomically, in bytes.
rtsectsize is the smallest amount of data that can be written to
the realtime device atomically, in bytes.
dirblocksize is the size of directory blocks, in bytes.
logsunit is what the filesystem has been told is the size of a
RAID stripe unit on the underlying log device, in filesystem
blocks. This field is meaningful only if the flag
XFS_FSOP_GEOM_FLAGS_LOGV2 is set.
The fields sick and checked indicate the relative health of
various whole-filesystem metadata. Please see the section XFS
METADATA HEALTH REPORTING for more details.
rgextents Is the number of RT extents in each rtgroup.
rtstart Start of the internal RT device in fsblocks. 0 if an
external RT device is used. This field is meaningful only if the
flag XFS_FSOP_GEOM_FLAGS_ZONED is set.
rtreserved The amount of space in the realtime section that is
reserved for internal use by garbage collection and reorganization
algorithms in fsblocks. This field is meaningful only if the flag
XFS_FSOP_GEOM_FLAGS_ZONED is set.
reserved is set to zero.
Filesystem features are reported to userspace as a combination the
following flags:
XFS_FSOP_GEOM_FLAGS_ATTR
Extended attributes are present.
XFS_FSOP_GEOM_FLAGS_NLINK
Files on this filesystem support up to 2^32 hard links. If
this flag is not set, files on this filesystem support only
up to 2^16 hard links.
XFS_FSOP_GEOM_FLAGS_QUOTA
Quotas are enabled.
XFS_FSOP_GEOM_FLAGS_IALIGN
Inodes are aligned for better performance.
XFS_FSOP_GEOM_FLAGS_DALIGN
Filesystem tries to align data block allocations to RAID
stripe units for better performance.
XFS_FSOP_GEOM_FLAGS_SHARED
Unused.
XFS_FSOP_GEOM_FLAGS_EXTFLG
Filesystem supports unwritten extents.
XFS_FSOP_GEOM_FLAGS_DIRV2
Directories are in version 2 format and maintain free space
data for better performance. Version 1 format directories
are no longer supported.
XFS_FSOP_GEOM_FLAGS_LOGV2
Log uses the V2 format.
XFS_FSOP_GEOM_FLAGS_SECTOR
The log device has a sector size larger than 512 bytes.
XFS_FSOP_GEOM_FLAGS_ATTR2
Filesystem contains V2 extended attributes.
XFS_FSOP_GEOM_FLAGS_PROJID32
Project IDs can be as large as 2^32. If this flag is not
set, the filesystem supports only 2^16 project IDs.
XFS_FSOP_GEOM_FLAGS_DIRV2CI
Case-insensitive lookups are supported on directories.
XFS_FSOP_GEOM_FLAGS_LAZYSB
On-disk superblock counters are updated only at unmount
time.
XFS_FSOP_GEOM_FLAGS_V5SB
Metadata blocks are self describing and contain checksums.
XFS_FSOP_GEOM_FLAGS_FTYPE
Directories contain inode types in directory entries.
XFS_FSOP_GEOM_FLAGS_FINOBT
Filesystem maintains an index of free inodes.
XFS_FSOP_GEOM_FLAGS_SPINODES
Filesystem may allocate discontiguous inode chunks when
free space is fragmented.
XFS_FSOP_GEOM_FLAGS_RMAPBT
Filesystem stores reverse mappings of blocks to owners.
XFS_FSOP_GEOM_FLAGS_REFLINK
Filesystem supports sharing blocks between files.
XFS_FSOP_GEOM_FLAGS_EXCHANGE_RANGE
Filesystem can exchange file contents atomically via
XFS_IOC_EXCHANGE_RANGE.
XFS_FSOP_GEOM_FLAGS_METADIR
Filesystem contains a metadata directory tree.
XFS_FSOP_GEOM_FLAGS_ZONED
Filesystem uses the zoned allocator for the RT device.
The online filesystem checking utility scans metadata and records
what it finds in the kernel incore state. The following scheme is
used for userspace to read the incore health status of the
filesystem:
• If a given sick flag is set in sick, then that piece of metadata
has been observed to be damaged. The same bit should be set in
checked.
• If a given sick flag is set in checked but is not set in sick,
then that piece of metadata has been checked and is not faulty.
• If a given sick flag is not set in checked, then no conclusion
can be made.
The following flags apply to these fields:
XFS_FSOP_GEOM_SICK_COUNTERS
Inode and space summary counters.
XFS_FSOP_GEOM_SICK_UQUOTA
User quota information.
XFS_FSOP_GEOM_SICK_GQUOTA
Group quota information.
XFS_FSOP_GEOM_SICK_PQUOTA
Project quota information.
XFS_FSOP_GEOM_SICK_RT_BITMAP
Free space bitmap for the realtime device.
XFS_FSOP_GEOM_SICK_RT_SUMMARY
Free space summary for the realtime device.
XFS_FSOP_GEOM_SICK_QUOTACHECK
Quota resource usage counters.
On error, -1 is returned, and errno is set to indicate the error.
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.
EIO An I/O error was encountered while performing the query.
This API is specific to XFS filesystem on the Linux kernel.
ioctl(2)
This page is part of the xfsprogs (utilities for XFS filesystems)
project. Information about the project can be found at
⟨http://xfs.org/⟩. If you have a bug report for this manual page,
send it to linux-xfs@vger.kernel.org. This page was obtained from
the project's upstream Git repository
⟨https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git⟩ on
2025-08-11. (At that time, the date of the most recent commit
that was found in the repository was 2025-06-23.) If you discover
any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page,
or you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a
mail to man-pages@man7.org
XFS 2019-06-17 IOCTL-XFS-FSGEOMETRY(2)
Pages that refer to this page: xfsctl(3)
Copyright and license for this manual page
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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