ioctl_xfs_getresblks(2) — Linux manual page

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

IOCTL-XFS-GETRESBLKS(2)    System Calls Manual   IOCTL-XFS-GETRESBLKS(2)

NAME         top

       ioctl_xfs_getresblks - query and set XFS free space reservation
       information

SYNOPSIS         top

       #include <xfs/xfs_fs.h>

       int ioctl(int fd, XFS_IOC_GET_RESBLKS, struct xfs_fsop_resblks
       *arg);
       int ioctl(int fd, XFS_IOC_SET_RESBLKS, struct xfs_fsop_resblks
       *arg);

DESCRIPTION         top

       Query or set the free space reservation information.  These
       blocks are reserved by the filesystem as a final attempt to
       prevent metadata update failures due to insufficient space.  Only
       the system administrator can use these ioctls, because overriding
       the defaults is extremely dangerous.

       This functionality is intended only for use by XFS filesystem
       developers.

       The reservation information is conveyed in a structure of the
       following form:

           struct xfs_fsop_resblks {
                __u64  resblks;
                __u64  resblks_avail;
           };

       resblks is the number of blocks that the filesystem will try to
       maintain to prevent critical out of space situations.

       resblks_avail is the number of reserved blocks remaining.

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.

       EPERM  Caller does not have permission to call this ioctl.

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
       2021-04-01.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-03-12.)  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-GETRESBLKS(2)

Pages that refer to this page: xfsctl(3)