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 [ -dfLnPv ] [ -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.

       -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.

       -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.

       -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.  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, 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 2017-07-05.  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: fsck.xfs(8)xfs_admin(8)xfs_db(8)xfs_mdrestore(8)xfs_metadump(8)