Provided by: xfsprogs_5.13.0-1ubuntu2.1_amd64 bug

NAME

       xfs_repair - repair an XFS filesystem

SYNOPSIS

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

DESCRIPTION

       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

       -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

       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

       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

       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

       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

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

                                                                                                   xfs_repair(8)