ioctl_xfs_ag_geometry(2) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | CONFORMING TO | SEE ALSO | COLOPHON

IOCTL-XFS-AG-GEOMETRY(2)     System Calls Manual    IOCTL-XFS-AG-GEOMETRY(2)

NAME         top

       ioctl_xfs_ag_geometry  - query XFS allocation group geometry informa‐
       tion

SYNOPSIS         top

       #include <xfs/xfs_fs.h>

       int ioctl(int fd, XFS_IOC_AG_GEOMETRY, struct xfs_ag_geometry *arg);

DESCRIPTION         top

       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:

       · 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         top

       On error, -1 is returned, and errno is set to indicate the error.

ERRORS         top

       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         top

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

SEE ALSO         top

       ioctl(2)

COLOPHON         top

       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
       2020-06-09.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-04-14.)  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                              2019-08-30         IOCTL-XFS-AG-GEOMETRY(2)

Pages that refer to this page: xfsctl(3)