Provided by: xfsprogs_2.7.7-1_i386 bug

NAME

       xfs_repair - repair an XFS filesystem

SYNOPSIS

       xfs_repair [ -nLvVd ] [ -o subopt[=value] ]
            [-l logdev] [-r rtdev] xfs_special

       xfs_repair -f [ -nLvVd ] [ -o subopt[=value] ]
            [-l logfile] [-r rtfile] file

DESCRIPTION

       xfs_repair  repairs  corrupt  or  damaged XFS filesystems (see xfs(5)).
       The filesystem is specified using the xfs_special 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.

       The options to xfs_repair are:

       -f     Specifies  that  the  special device is actually a file (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.

       -l     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     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.

       -o     Override what the program might conclude about the filesystem if
              left to its own devices.

              The assume_xfs suboption specifies that the filesystem is an XFS
              filesystem.   Normally,  if  xfs_repair  cannot  find   an   XFS
              superblock,  it  checks  to  see  if  the  filesystem  is an EFS
              filesystem before it tries to regenerate the XFS superblock.  If
              the  assume_xfs option is in effect, xfs_repair will assume that
              the filesystem is an XFS  filesystem  and  will  ignore  an  EFS
              superblock if one is found.

       -v     Verbose output.

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

   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  writeable  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 the lost+found directory already exists, the
       lost+found  directory  is  deleted  and recreated every time xfs_repair
       runs.  This ensures that there are no  name  conflicts  in  lost+found.
       However,  if  you  rename  a  file in lost+found and leave it there, if
       xfs_repair is run again, that file is renamed back to its inode number.

   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 xxxx, moving to lost+found

              An inode numbered xxxx  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  (i-number).
              If  a  lost+found  directory does not exist, it is automatically
              created.

       disconnected dir inode xxxx, 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 xxxx is free, correcting imap

              The  inode allocation map thinks that inode xxxx 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 xxxx is in use, correcting imap

              The inode allocation map  thinks  that  inode  xxxx  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 xxxx nlinks from x to y

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

       fork-type fork in ino xxxx claims used block yyyy

              Inode xxxx claims a block yyyy 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 xxxx claims dup extent ...

              Inode xxxx 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 xxxx - bad extent ...

              An extent record in the blockmap of  inode  xxxx  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)
              exent.

       bad fork-type fork in inode xxxx

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

       cleared inode xxxx

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

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

       entry "name" in dir xxxx references already  connected  dir  ino  yyyy,
       junking entry "name" in directory inode xxxx

              The  entry  "name" in directory inode xxxx points to a directory
              inode yyyy 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 xxxx in directory yyyy, will clear entry

              An  entry  in directory inode yyyy references an inode xxxx 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 node) 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.

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.

SEE ALSO

       dd(1), mkfs.xfs(8), umount(8), xfs_check(8), xfs(5).

                                                                 xfs_repair(8)