Provided by: e2fsprogs_1.42-1ubuntu2_i386 bug

NAME

       e2fsck - check a Linux ext2/ext3/ext4 file system

SYNOPSIS

       e2fsck  [  -pacnyrdfkvtDFV ] [ -b superblock ] [ -B blocksize ] [ -l|-L
       bad_blocks_file  ]  [  -C  fd  ]  [  -j   external-journal   ]   [   -E
       extended_options ] device

DESCRIPTION

       e2fsck is used to check the ext2/ext3/ext4 family of file systems.  For
       ext3 and ext4 filesystems that use a journal, if the  system  has  been
       shut  down  uncleanly without any errors, normally, after replaying the
       committed transactions  in the  journal,  the  file  system  should  be
       marked  as clean.   Hence, for filesystems that use journalling, e2fsck
       will normally replay  the  journal  and  exit,  unless  its  superblock
       indicates that further checking is required.

       device  is  the  device  file  where  the  filesystem  is  stored (e.g.
       /dev/hdc1).

       Note that  in  general  it  is  not  safe  to  run  e2fsck  on  mounted
       filesystems.   The only exception is if the -n option is specified, and
       -c, -l, or -L options are not specified.   However, even if it is  safe
       to do so, the results printed by e2fsck are not valid if the filesystem
       is mounted.   If  e2fsck  asks  whether  or  not  you  should  check  a
       filesystem  which  is mounted, the only correct answer is ``no''.  Only
       experts who really know what they are doing should  consider  answering
       this question in any other way.

OPTIONS

       -a     This  option  does  the  same  thing  as  the  -p option.  It is
              provided for backwards compatibility only; it is suggested  that
              people use -p option whenever possible.

       -b superblock
              Instead  of  using  the  normal  superblock,  use an alternative
              superblock specified by superblock.   This  option  is  normally
              used  when  the  primary  superblock  has  been  corrupted.  The
              location  of  the  backup  superblock  is   dependent   on   the
              filesystem's  blocksize.   For filesystems with 1k blocksizes, a
              backup superblock can be found at block  8193;  for  filesystems
              with  2k  blocksizes,  at block 16384; and for 4k blocksizes, at
              block 32768.

              Additional backup superblocks can be  determined  by  using  the
              mke2fs  program  using  the  -n  option  to  print out where the
              superblocks were created.    The  -b  option  to  mke2fs,  which
              specifies blocksize of the filesystem must be specified in order
              for  the  superblock  locations  that  are  printed  out  to  be
              accurate.

              If  an alternative superblock is specified and the filesystem is
              not opened read-only, e2fsck will make  sure  that  the  primary
              superblock  is  updated  appropriately  upon  completion  of the
              filesystem check.

       -B blocksize
              Normally, e2fsck will  search  for  the  superblock  at  various
              different  block  sizes  in  an  attempt to find the appropriate
              block size.  This search can be  fooled  in  some  cases.   This
              option  forces  e2fsck  to only try locating the superblock at a
              particular blocksize.  If the superblock is  not  found,  e2fsck
              will terminate with a fatal error.

       -c     This  option  causes  e2fsck to use badblocks(8) program to do a
              read-only scan of the device in order to find  any  bad  blocks.
              If  any  bad  blocks  are found, they are added to the bad block
              inode to  prevent  them  from  being  allocated  to  a  file  or
              directory.   If  this  option  is  specified twice, then the bad
              block scan will be done using a non-destructive read-write test.

       -C fd  This option causes e2fsck to write completion information to the
              specified file descriptor so that the progress of the filesystem
              check can be  monitored.   This  option  is  typically  used  by
              programs  which  are  running  e2fsck.   If  the file descriptor
              number is negative, then absolute value of the  file  descriptor
              will  be  used,  and the progress information will be suppressed
              initially.  It can  later  be  enabled  by  sending  the  e2fsck
              process  a  SIGUSR1 signal.  If the file descriptor specified is
              0, e2fsck will print a completion  bar  as  it  goes  about  its
              business.   This  requires  that  e2fsck  is  running on a video
              console or terminal.

       -d     Print  debugging  output  (useless  unless  you  are   debugging
              e2fsck).

       -D     Optimize  directories  in filesystem.  This option causes e2fsck
              to try to optimize all directories, either by reindexing them if
              the  filesystem  supports directory indexing,  or by sorting and
              compressing  directories  for  smaller   directories,   or   for
              filesystems using traditional linear directories.

              Even  without the -D option, e2fsck may sometimes optimize a few
              directories --- for example, if directory  indexing  is  enabled
              and  a  directory  is  not  indexed and would benefit from being
              indexed, or if the index structures are corrupted and need to be
              rebuilt.  The -D option forces all directories in the filesystem
              to be optimized.  This can sometimes make them a little  smaller
              and  slightly  faster  to  search,  but  in practice, you should
              rarely need to use this option.

              The -D option will detect directory entries with duplicate names
              in  a  single  directory, which e2fsck normally does not enforce
              for performance reasons.

       -E extended_options
              Set  e2fsck  extended  options.   Extended  options  are   comma
              separated, and may take an argument using the equals ('=') sign.
              The following options are supported:

                   ea_ver=extended_attribute_version
                          Set the version of  the  extended  attribute  blocks
                          which   e2fsck   will  require  while  checking  the
                          filesystem.  The version number may be 1 or 2.   The
                          default extended attribute version format is 2.

                   journal_only
                          Only  replay  the  journal  if  required, but do not
                          perform any further checks or repairs.

                   fragcheck
                          During pass  1,  print  a  detailed  report  of  any
                          discontiguous blocks for files in the filesystem.

                   discard
                          Attempt  to  discard  free  blocks  and unused inode
                          blocks after the full filesystem  check  (discarding
                          blocks is useful on solid state devices and sparse /
                          thin-provisioned storage). Note that discard is done
                          in  pass  5  AFTER  the  filesystem  has  been fully
                          checked and only if it does not contain recognizable
                          errors.  However  there  might be cases where e2fsck
                          does not fully recognise a problem and hence in this
                          case this option may prevent you from further manual
                          data recovery.

                   nodiscard
                          Do not attempt to discard  free  blocks  and  unused
                          inode blocks. This option is exactly the opposite of
                          discard option. This is set as default.

       -f     Force checking even if the file system seems clean.

       -F     Flush the filesystem device's buffer  caches  before  beginning.
              Only really useful for doing e2fsck time trials.

       -j external-journal
              Set  the pathname where the external-journal for this filesystem
              can be found.

       -k     When combined with the -c option, any existing bad blocks in the
              bad  blocks  list are preserved, and any new bad blocks found by
              running badblocks(8) will be added to the  existing  bad  blocks
              list.

       -l filename
              Add  the  block numbers listed in the file specified by filename
              to the list of bad blocks.  The format of this file is the  same
              as the one generated by the badblocks(8) program.  Note that the
              block numbers are based on  the  blocksize  of  the  filesystem.
              Hence,   badblocks(8)   must  be  given  the  blocksize  of  the
              filesystem in order to obtain correct results.  As a result,  it
              is  much simpler and safer to use the -c option to e2fsck, since
              it will assure that the correct parameters  are  passed  to  the
              badblocks program.

       -L filename
              Set  the  bad  blocks list to be the list of blocks specified by
              filename.  (This option is the same as the -l option, except the
              bad  blocks list is cleared before the blocks listed in the file
              are added to the bad blocks list.)

       -n     Open the filesystem read-only, and assume an answer of  `no'  to
              all  questions.   Allows  e2fsck  to  be used non-interactively.
              This option may not be specified at the same time as the  -p  or
              -y options.

       -p     Automatically  repair  ("preen")  the  file system.  This option
              will cause e2fsck to automatically fix any  filesystem  problems
              that  can be safely fixed without human intervention.  If e2fsck
              discovers a problem which may require the  system  administrator
              to  take  additional  corrective  action,  e2fsck  will  print a
              description of the problem  and  then  exit  with  the  value  4
              logically  or'ed  into  the  exit  code.   (See  the  EXIT  CODE
              section.)  This option is normally used  by  the  system's  boot
              scripts.   It may not be specified at the same time as the -n or
              -y options.

       -r     This option does  nothing  at  all;  it  is  provided  only  for
              backwards compatibility.

       -t     Print  timing  statistics  for  e2fsck.   If this option is used
              twice, additional timing statistics are printed  on  a  pass  by
              pass basis.

       -v     Verbose mode.

       -V     Print version information and exit.

       -y     Assume  an answer of `yes' to all questions; allows e2fsck to be
              used non-interactively.  This option may not be specified at the
              same time as the -n or -p options.

EXIT CODE

       The  exit  code  returned  by  e2fsck  is  the  sum  of  the  following
       conditions:
            0    - No errors
            1    - File system errors corrected
            2    - File system errors corrected, system should
                   be rebooted
            4    - File system errors left uncorrected
            8    - Operational error
            16   - Usage or syntax error
            32   - E2fsck canceled by user request
            128  - Shared library error

SIGNALS

       The following signals have the following effect when sent to e2fsck.

       SIGUSR1
              This signal causes e2fsck to start displaying a  completion  bar
              or  emitting  progress  information.   (See discussion of the -C
              option.)

       SIGUSR2
              This signal causes e2fsck to stop displaying a completion bar or
              emitting progress information.

REPORTING BUGS

       Almost  any  piece of software will have bugs.  If you manage to find a
       filesystem which causes e2fsck to crash, or which e2fsck is  unable  to
       repair, please report it to the author.

       Please  include  as  much  information  as possible in your bug report.
       Ideally, include a complete transcript of the e2fsck run, so I can  see
       exactly  what  error  messages  are displayed.  (Make sure the messages
       printed by e2fsck are in English; if your system has been configured so
       that  e2fsck's  messages  have  been  translated into another language,
       please set the the  LC_ALL  environment  variable  to  C  so  that  the
       transcript  of  e2fsck's  output  will be useful to me.)  If you have a
       writable filesystem where the transcript can be stored,  the  script(1)
       program is a handy way to save the output of e2fsck to a file.

       It  is  also  useful  to send the output of dumpe2fs(8).  If a specific
       inode or inodes seems to be giving  e2fsck  trouble,  try  running  the
       debugfs(8)  command  and send the output of the stat(1u) command run on
       the relevant inode(s).  If the inode is a directory, the  debugfs  dump
       command  will allow you to extract the contents of the directory inode,
       which can sent to me after being first run  through  uuencode(1).   The
       most useful data you can send to help reproduce the bug is a compressed
       raw image dump of the filesystem, generated using e2image(8).  See  the
       e2image(8) man page for more details.

       Always include the full version string which e2fsck displays when it is
       run, so I know which version you are running.

AUTHOR

       This version of e2fsck was written by Theodore Ts'o <tytso@mit.edu>.

SEE ALSO

       e2fsck.conf(5),  badblocks(8),  dumpe2fs(8),  debugfs(8),   e2image(8),
       mke2fs(8), tune2fs(8)