xfs_repair(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | DIAGNOSTICS | EXIT STATUS | DIRTY LOGS | BUGS | SEE ALSO | COLOPHON

xfs_repair(8)            System Manager's Manual           xfs_repair(8)

NAME         top

       xfs_repair - repair an XFS filesystem

SYNOPSIS         top

       xfs_repair [ -dfLPv ] [ -n | -e ] [ -m maxmem ] [ -c subopt=value
       ] [ -o subopt[=value] ] [ -t interval ] [ -l logdev ] [ -r rtdev
       ] device
       xfs_repair -V

DESCRIPTION         top

       xfs_repair repairs corrupt or damaged XFS filesystems (see
       xfs(5)).  The filesystem is specified using the device argument
       which should be the device name of the disk partition or volume
       containing the filesystem. If given the name of a block device,
       xfs_repair will attempt to find the raw device associated with
       the specified block device and will use the raw device instead.

       Regardless, the filesystem to be repaired must be unmounted,
       otherwise, the resulting filesystem may be inconsistent or
       corrupt.

OPTIONS         top

       -f     Specifies that the filesystem image to be processed is
              stored in a regular file at device (see the mkfs.xfs -d
              file option). This might happen if an image copy of a
              filesystem has been copied or written into an ordinary
              file.  This option implies that any external log or
              realtime section is also in an ordinary file.

       -L     Force Log Zeroing.  Forces xfs_repair to zero the log even
              if it is dirty (contains metadata changes).  When using
              this option the filesystem will likely appear to be
              corrupt, and can cause the loss of user files and/or data.
              See the DIRTY LOGS section for more information.

       -l logdev
              Specifies the device special file where the filesystem's
              external log resides. Only for those filesystems which use
              an external log.  See the mkfs.xfs -l option, and refer to
              xfs(5) for a detailed description of the XFS log.

       -r rtdev
              Specifies the device special file where the filesystem's
              realtime section resides. Only for those filesystems which
              use a realtime section.  See the mkfs.xfs -r option, and
              refer to xfs(5) for a detailed description of the XFS
              realtime section.

       -n     No modify mode. Specifies that xfs_repair should not
              modify the filesystem but should only scan the filesystem
              and indicate what repairs would have been made. This
              option cannot be used together with -e.

       -P     Disable prefetching of inode and directory blocks. Use
              this option if you find xfs_repair gets stuck and stops
              proceeding. Interrupting a stuck xfs_repair is safe.

       -m maxmem
              Specifies the approximate maximum amount of memory, in
              megabytes, to use for xfs_repair.  xfs_repair has its own
              internal block cache which will scale out up to the lesser
              of the process's virtual address limit or about 75% of the
              system's physical RAM.  This option overrides these
              limits.

              NOTE: These memory limits are only approximate and may use
              more than the specified limit.

       -c subopt=value
              Change filesystem parameters. Refer to xfs_admin(8) for
              information on changing filesystem parameters.

       -o subopt[=value]
              Override what the program might conclude about the
              filesystem if left to its own devices.

              The suboptions supported are:

                 bhash=bhashsize
                        overrides the default buffer cache hash size.
                        The total number of buffer cache entries are
                        limited to 8 times this amount. The default size
                        is set to use up the remainder of 75% of the
                        system's physical RAM size.

                 ag_stride=ags_per_concat_unit
                        This creates additional processing threads to
                        parallel process AGs that span multiple concat
                        units. This can significantly reduce repair
                        times on concat based filesystems.

                 force_geometry
                        Check the filesystem even if geometry
                        information could not be validated.  Geometry
                        information can not be validated if only a
                        single allocation group exists and thus we do
                        not have a backup superblock available, or if
                        there are two allocation groups and the two
                        superblocks do not agree on the filesystem
                        geometry.  Only use this option if you validated
                        the geometry yourself and know what you are
                        doing.  If In doubt run in no modify mode first.

                 noquota
                        Don't validate quota counters at all.
                        Quotacheck will be run during the next mount to
                        recalculate all values.

       -t  interval
              Modify reporting interval, specified in seconds. During
              long runs xfs_repair outputs its progress every 15
              minutes. Reporting is only activated when ag_stride is
              enabled.

       -v     Verbose output.  May be specified multiple times to
              increase verbosity.

       -d     Repair dangerously. Allow xfs_repair to repair an XFS
              filesystem mounted read only. This is typically done on a
              root filesystem from single user mode, immediately
              followed by a reboot.

       -e     If any metadata corruption was repaired, the status
              returned is 4 instead of the usual 0. This option cannot
              be used together with -n.

       -V     Prints the version number and exits.

   Checks Performed
       Inconsistencies corrected include the following:

       1.     Inode and inode blockmap (addressing) checks: bad magic
              number in inode, bad magic numbers in inode blockmap
              blocks, extents out of order, incorrect number of records
              in inode blockmap blocks, blocks claimed that are not in a
              legal data area of the filesystem, blocks that are claimed
              by more than one inode.

       2.     Inode allocation map checks: bad magic number in inode map
              blocks, inode state as indicated by map (free or in-use)
              inconsistent with state indicated by the inode, inodes
              referenced by the filesystem that do not appear in the
              inode allocation map, inode allocation map referencing
              blocks that do not appear to contain inodes.

       3.     Size checks: number of blocks claimed by inode
              inconsistent with inode size, directory size not block
              aligned, inode size not consistent with inode format.

       4.     Directory checks: bad magic numbers in directory blocks,
              incorrect number of entries in a directory block, bad
              freespace information in a directory leaf block, entry
              pointing to an unallocated (free) or out of range inode,
              overlapping entries, missing or incorrect dot and dotdot
              entries, entries out of hashvalue order, incorrect
              internal directory pointers, directory type not consistent
              with inode format and size.

       5.     Pathname checks: files or directories not referenced by a
              pathname starting from the filesystem root, illegal
              pathname components.

       6.     Link count checks: link counts that do not agree with the
              number of directory references to the inode.

       7.     Freemap checks: blocks claimed free by the freemap but
              also claimed by an inode, blocks unclaimed by any inode
              but not appearing in the freemap.

       8.     Super Block checks: total free block and/or free i-node
              count incorrect, filesystem geometry inconsistent,
              secondary and primary superblocks contradictory.

       Orphaned files and directories (allocated, in-use but
       unreferenced) are reconnected by placing them in the lost+found
       directory.  The name assigned is the inode number.

   Disk Errors
       xfs_repair aborts on most disk I/O errors. Therefore, if you are
       trying to repair a filesystem that was damaged due to a disk
       drive failure, steps should be taken to ensure that all blocks in
       the filesystem are readable and writable before attempting to use
       xfs_repair to repair the filesystem. A possible method is using
       dd(8) to copy the data onto a good disk.

   lost+found
       The directory lost+found does not have to already exist in the
       filesystem being repaired.  If the directory does not exist, it
       is automatically created if required.  If it already exists, it
       will be checked for consistency and if valid will be used for
       additional orphaned files. Invalid lost+found directories are
       removed and recreated. Existing files in a valid lost+found are
       not removed or renamed.

   Corrupted Superblocks
       XFS has both primary and secondary superblocks.  xfs_repair uses
       information in the primary superblock to automatically find and
       validate the primary superblock against the secondary superblocks
       before proceeding.  Should the primary be too corrupted to be
       useful in locating the secondary superblocks, the program scans
       the filesystem until it finds and validates some secondary
       superblocks.  At that point, it generates a primary superblock.

   Quotas
       If quotas are in use, it is possible that xfs_repair will clear
       some or all of the filesystem quota information.  If so, the
       program issues a warning just before it terminates.  If all quota
       information is lost, quotas are disabled and the program issues a
       warning to that effect.

       Note that xfs_repair does not check the validity of quota limits.
       It is recommended that you check the quota limit information
       manually after xfs_repair.  Also, space usage information is
       automatically regenerated the next time the filesystem is mounted
       with quotas turned on, so the next quota mount of the filesystem
       may take some time.

DIAGNOSTICS         top

       xfs_repair issues informative messages as it proceeds indicating
       what it has found that is abnormal or any corrective action that
       it has taken.  Most of the messages are completely understandable
       only to those who are knowledgeable about the structure of the
       filesystem.  Some of the more common messages are explained here.
       Note that the language of the messages is slightly different if
       xfs_repair is run in no-modify mode because the program is not
       changing anything on disk.  No-modify mode indicates what it
       would do to repair the filesystem if run without the no-modify
       flag.

       disconnected inode ino, moving to lost+found

              An inode numbered ino was not connected to the filesystem
              directory tree and was reconnected to the lost+found
              directory. The inode is assigned the name of its inode
              number (ino).  If a lost+found directory does not exist,
              it is automatically created.

       disconnected dir inode ino, moving to lost+found

              As above only the inode is a directory inode.  If a
              directory inode is attached to lost+found, all of its
              children (if any) stay attached to the directory and
              therefore get automatically reconnected when the directory
              is reconnected.

       imap claims in-use inode ino is free, correcting imap

              The inode allocation map thinks that inode ino is free
              whereas examination of the inode indicates that the inode
              may be in use (although it may be disconnected).  The
              program updates the inode allocation map.

       imap claims free inode ino is in use, correcting imap

              The inode allocation map thinks that inode ino is in use
              whereas examination of the inode indicates that the inode
              is not in use and therefore is free.  The program updates
              the inode allocation map.

       resetting inode ino nlinks from x to y

              The program detected a mismatch between the number of
              valid directory entries referencing inode ino and the
              number of references recorded in the inode and corrected
              the the number in the inode.

       fork-type fork in ino ino claims used block bno

              Inode ino claims a block bno that is used (claimed) by
              either another inode or the filesystem itself for metadata
              storage. The fork-type is either data or attr indicating
              whether the problem lies in the portion of the inode that
              tracks regular data or the portion of the inode that
              stores XFS attributes.  If the inode is a real-time (rt)
              inode, the message says so.  Any inode that claims blocks
              used by the filesystem is deleted.  If two or more inodes
              claim the same block, they are both deleted.

       fork-type fork in ino ino claims dup extent ...

              Inode ino claims a block in an extent known to be claimed
              more than once.  The offset in the inode, start and length
              of the extent is given.  The message is slightly different
              if the inode is a real-time (rt) inode and the extent is
              therefore a real-time (rt) extent.

       inode ino - bad extent ...

              An extent record in the blockmap of inode ino claims
              blocks that are out of the legal range of the filesystem.
              The message supplies the start, end, and file offset of
              the extent.  The message is slightly different if the
              extent is a real-time (rt) extent.

       bad fork-type fork in inode ino

              There was something structurally wrong or inconsistent
              with the data structures that map offsets to filesystem
              blocks.

       cleared inode ino

              There was something wrong with the inode that was
              uncorrectable so the program freed the inode.  This
              usually happens because the inode claims blocks that are
              used by something else or the inode itself is badly
              corrupted. Typically, this message is preceded by one or
              more messages indicating why the inode needed to be
              cleared.

       bad attribute fork in inode ino, clearing attr fork

              There was something wrong with the portion of the inode
              that stores XFS attributes (the attribute fork) so the
              program reset the attribute fork.  As a result of this,
              all attributes on that inode are lost.

       correcting nextents for inode ino, was x - counted y

              The program found that the number of extents used to store
              the data in the inode is wrong and corrected the number.
              The message refers to nextents if the count is wrong on
              the number of extents used to store attribute information.

       entry name in dir dir_ino not consistent with .. value (xxxx) in
       dir ino ino, junking entry name in directory inode dir_ino

              The entry name in directory inode dir_ino references a
              directory inode ino.  However, the .. entry in directory
              ino does not point back to directory dir_ino, so the
              program deletes the entry name in directory inode dir_ino.
              If the directory inode ino winds up becoming a
              disconnected inode as a result of this, it is moved to
              lost+found later.

       entry name in dir dir_ino references already connected dir ino
       ino, junking entry name in directory inode dir_ino

              The entry name in directory inode dir_ino points to a
              directory inode ino that is known to be a child of another
              directory.  Therefore, the entry is invalid and is
              deleted.  This message refers to an entry in a small
              directory.  If this were a large directory, the last
              phrase would read "will clear entry".

       entry references free inode ino in directory dir_ino, will clear
       entry

              An entry in directory inode dir_ino references an inode
              ino that is known to be free. The entry is therefore
              invalid and is deleted.  This message refers to a large
              directory.  If the directory were small, the message would
              read "junking entry ...".

EXIT STATUS         top

       xfs_repair -n (no modify mode) will return a status of 1 if
       filesystem corruption was detected and 0 if no filesystem
       corruption was detected.  xfs_repair run without the -n option
       will always return a status code of 0 if it completes without
       problems, unless the flag -e is used. If it is used, then status
       4 is reported when any issue with the filesystem was found, but
       could be fixed. If a runtime error is encountered during
       operation, it will return a status of 1. In this case, xfs_repair
       should be restarted.  If xfs_repair is unable to proceed due to a
       dirty log, it will return a status of 2.  See below.

DIRTY LOGS         top

       Due to the design of the XFS log, a dirty log can only be
       replayed by the kernel, on a machine having the same CPU
       architecture as the machine which was writing to the log.
       xfs_repair cannot replay a dirty log and will exit with a status
       code of 2 when it detects a dirty log.

       In this situation, the log can be replayed by mounting and
       immediately unmounting the filesystem on the same class of
       machine that crashed.  Please make sure that the machine's
       hardware is reliable before replaying to avoid compounding the
       problems.

       If mounting fails, the log can be erased by running xfs_repair
       with the -L option.  All metadata updates in progress at the time
       of the crash will be lost, which may cause significant filesystem
       damage.  This should only be used as a last resort.

BUGS         top

       The filesystem to be checked and repaired must have been
       unmounted cleanly using normal system administration procedures
       (the umount(8) command or system shutdown), not as a result of a
       crash or system reset.  If the filesystem has not been unmounted
       cleanly, mount it and unmount it cleanly before running
       xfs_repair.

       xfs_repair does not do a thorough job on XFS extended attributes.
       The structure of the attribute fork will be consistent, but only
       the contents of attribute forks that will fit into an inode are
       checked.  This limitation will be fixed in the future.

       The no-modify mode (-n option) is not completely accurate.  It
       does not catch inconsistencies in the freespace and inode maps,
       particularly lost blocks or subtly corrupted maps (trees).

       The no-modify mode can generate repeated warnings about the same
       problems because it cannot fix the problems as they are
       encountered.

       If a filesystem fails to be repaired, a metadump image can be
       generated with xfs_metadump(8) and be sent to an XFS maintainer
       to be analysed and xfs_repair fixed and/or improved.

SEE ALSO         top

       dd(1), mkfs.xfs(8), umount(8), xfs_admin(8), xfs_metadump(8),
       xfs(5).

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
       2020-12-18.  (At that time, the date of the most recent commit
       that was found in the repository was 2020-12-11.)  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_repair(8)

Pages that refer to this page: ioctl_xfs_scrub_metadata(2)fsck.xfs(8)xfs_admin(8)xfs_db(8)xfs_mdrestore(8)xfs_metadump(8)xfs_scrub(8)