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

IOCTL-XFS-SCRUB-METADATA(2)  System Calls Manual IOCTL-XFS-SCRUB-METADATA(2)

NAME         top

       ioctl_xfs_scrub_metadata - check XFS filesystem metadata

SYNOPSIS         top

       #include <xfs/xfs_fs.h>

       int ioctl(int dest_fd, XFS_IOC_SCRUB_METADATA, struct
       xfs_scrub_metadata *arg);

DESCRIPTION         top

       This XFS ioctl asks the kernel driver to examine a piece of
       filesystem metadata for errors or suboptimal metadata.  Examination
       includes running metadata verifiers, checking records for obviously
       incorrect or impossible values, and cross-referencing each record
       with any other available metadata in the filesystem.  This ioctl can
       also try to repair or optimize metadata, though this may block normal
       filesystem operations for a long period of time.  The type and
       location of the metadata to scrub is conveyed in a structure of the
       following form:

           struct xfs_scrub_metadata {
                __u32 sm_type;
                __u32 sm_flags;
                __u64 sm_ino;
                __u32 sm_gen;
                __u32 sm_agno;
                __u64 sm_reserved[5];
           };

       The field sm_reserved must be zero.

       The field sm_type indicates the type of metadata to check:

           XFS_SCRUB_TYPE_PROBE
                  Probe the kernel to see if it is willing to try to check
                  or repair this filesystem.  sm_agno, sm_ino, and sm_gen
                  must be zero.

           XFS_SCRUB_TYPE_SB
           XFS_SCRUB_TYPE_AGF
           XFS_SCRUB_TYPE_AGFL
           XFS_SCRUB_TYPE_AGI
                  Examine a given allocation group's superblock, free space
                  header, free block list, or inode header, respectively.
                  Headers are checked for obviously incorrect values and
                  cross-referenced against the allocation group's metadata
                  btrees, if possible.  The allocation group number must be
                  given in sm_agno.  sm_ino and sm_gen must be zero.

           XFS_SCRUB_TYPE_BNOBT
           XFS_SCRUB_TYPE_CNTBT
           XFS_SCRUB_TYPE_INOBT
           XFS_SCRUB_TYPE_FINOBT
           XFS_SCRUB_TYPE_RMAPBT
           XFS_SCRUB_TYPE_REFCNTBT
                  Examine a given allocation group's two free space btrees,
                  two inode btrees, reverse mapping btrees, or reference
                  count btrees, respectively.  Records are checked for
                  obviously incorrect values and cross-referenced with other
                  allocation group metadata records to ensure that there are
                  no conflicts.  The allocation group number must be given
                  in sm_agno.  sm_ino and sm_gen must be zero.

           XFS_SCRUB_TYPE_INODE
                  Examine a given inode record for obviously incorrect
                  values and discrepancies with the rest of filesystem
                  metadata.  Parent pointers are checked for impossible
                  inode values and are then followed up to the parent
                  directory to ensure that the linkage is correct.  The
                  inode to examine may be specified either through sm_ino
                  and sm_gen; if not specified, then the file described by
                  dest_fd will be examined.  sm_agno must be zero.

           XFS_SCRUB_TYPE_BMBTD
           XFS_SCRUB_TYPE_BMBTA
           XFS_SCRUB_TYPE_BMBTC
           XFS_SCRUB_TYPE_PARENT
                  Examine a given inode's data block map, extended attribute
                  block map, copy on write block map, or parent inode
                  pointer.  Inode records are examined for obviously
                  incorrect values and discrepancies with the three block
                  map types.  The block maps are checked for obviously wrong
                  values and cross-referenced with the allocation group
                  space extent metadata for discrepancies.  The inode to
                  examine can be specified in the same manner as
                  XFS_SCRUB_TYPE_INODE.

           XFS_SCRUB_TYPE_XATTR
                  Examine the extended attribute records and indices of a
                  given inode for incorrect pointers and other signs of
                  damage.  The inode to examine can be specified in the same
                  manner as XFS_SCRUB_TYPE_INODE.

           XFS_SCRUB_TYPE_DIR
                  Examine the entries in a given directory for invalid data
                  or dangling pointers.  The directory to examine can be
                  specified in the same manner as XFS_SCRUB_TYPE_INODE.

           XFS_SCRUB_TYPE_SYMLINK
                  Examine the target of a symbolic link for obvious pathname
                  problems.  The link to examine can be specified in the
                  same manner as XFS_SCRUB_TYPE_INODE.

           XFS_SCRUB_TYPE_RTBITMAP
           XFS_SCRUB_TYPE_RTSUM
                  Examine the realtime block bitmap and realtime summary
                  inodes for corruption.

           XFS_SCRUB_TYPE_UQUOTA
           XFS_SCRUB_TYPE_GQUOTA
           XFS_SCRUB_TYPE_PQUOTA
                  Examine all user, group, or project quota records for
                  corruption.

       The field sm_flags control the behavior of the scrub operation and
       provide more information about the outcome of the operation.  If none
       of the XFS_SCRUB_OFLAG_* flags are set upon return, the metadata is
       clean.

           XFS_SCRUB_IFLAG_REPAIR
                  If the caller sets this flag, the kernel driver will
                  examine the metadata and try to fix all problems and to
                  optimize metadata when possible.  If no errors occur
                  during the repair operation, the check is performed a
                  second time to determine whether the repair succeeded.  If
                  errors occur, the call returns an error status
                  immediately.

           XFS_SCRUB_OFLAG_CORRUPT
                  The metadata was corrupt when the call returned.  If
                  XFS_SCRUB_IFLAG_REPAIR was specified, then an attempted
                  repair failed to fix the problem.  Unmount the filesystem
                  and run xfs_repair to fix the filesystem.

           XFS_SCRUB_OFLAG_PREEN
                  The metadata is ok, but some aspect of the metadata could
                  be optimized to increase performance.  Call again with
                  XFS_SCRUB_IFLAG_REPAIR to optimize the metadata.

           XFS_SCRUB_OFLAG_XFAIL
                  Filesystem errors were encountered when accessing other
                  metadata to cross-reference the records attached to this
                  metadata object.

           XFS_SCRUB_OFLAG_XCORRUPT
                  Discrepancies were found when cross-referencing the
                  records attached to this metadata object against all other
                  available metadata in the system.

           XFS_SCRUB_OFLAG_INCOMPLETE
                  The checker was unable to complete its check of all
                  records.

           XFS_SCRUB_OFLAG_WARNING
                  The checker encountered a metadata object with potentially
                  problematic records.  However, the records were not
                  obviously corrupt.

       For metadata checkers that operate on inodes or inode metadata, the
       fields sm_ino and sm_gen are the inode number and generation number
       of the inode to check.  If the inode number is zero, the inode
       represented by dest_fd is used instead.  If the generation number of
       the inode does not match sm_gen, the call will return an error code
       for the invalid argument.  The sm_agno field must be zero.

       For metadata checkers that operate on allocation group metadata, the
       field sm_agno indicates the allocation group in which to find the
       metadata.  The sm_ino and sm_gen fields must be zero.

       For metadata checkers that operate on filesystem-wide metadata, no
       further arguments are required.  sm_agno, sm_ino, and sm_gen must all
       be zero.

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:

       EBUSY  The filesystem object is busy; the operation will have to be
              tried again.

       EFSCORRUPTED
              Severe filesystem corruption was detected and could not be
              repaired.  Unmount the filesystem and run xfs_repair to fix
              the filesystem.

       EINVAL One or more of the arguments specified is invalid.

       ENOENT The specified metadata object does not exist.  For example,
              this error code is returned for a XFS_SCRUB_TYPE_REFCNTBT
              request on a filesystem that does not support reflink.

       ENOMEM There was not sufficient memory to perform the scrub or repair
              operation.  Some operations (most notably reference count
              checking) require large amounts of memory.

       ENOSPC There is not enough free disk space to attempt a repair.

       ENOTRECOVERABLE
              Filesystem was mounted in norecovery mode and therefore has an
              unclean log.  Neither scrub nor repair operations can be
              attempted with an unclean log.

       ENOTTY Online scrubbing or repair were not enabled.

       EOPNOTSUPP
              Repairs of the requested metadata object are not supported.

       EROFS  Filesystem is read-only and a repair was requested.

       ESHUTDOWN
              Filesystem is shut down due to previous errors.

CONFORMING TO         top

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

NOTES         top

       These operations may block other filesystem operations for a long
       time.  A calling process can stop the operation by being sent a fatal
       signal, but non-fatal signals are blocked.

SEE ALSO         top

       ioctl(2) xfs_scrub(8) xfs_repair(8)

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, see
       ⟨http://oss.sgi.com/bugzilla/buglist.cgi?product=XFS⟩.  This page was
       obtained from the project's upstream Git repository
       ⟨git://oss.sgi.com/xfs/cmds/xfsprogs⟩ on 2018-10-29.  (At that time,
       the date of the most recent commit that was found in the repository
       was 2018-08-24.)  If you discover any rendering problems in this HTML
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       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                              2017-12-01      IOCTL-XFS-SCRUB-METADATA(2)