e2fsck



E2FSCK(8)                                                            E2FSCK(8)




NAME

       e2fsck - check a Linux ext2/ext3 file system


SYNOPSIS

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


DESCRIPTION

       e2fsck  is  used to check a Linux second extended file system (ext2fs).
       E2fsck also supports ext2 filesystems containing a journal,  which  are
       also sometimes known as ext3 filesystems, by first applying the journal
       to the filesystem before  continuing  with  normal  e2fsck  processing.
       After  the  journal  has  been  applied,  a filesystem will normally be
       marked as clean.  Hence, for ext3 filesystems, e2fsck will normally run
       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 filesys-
       tems.  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  pro-
              vided  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  loca-
              tion  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 spec-
              ifies 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  dif-
              ferent  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 particu-
              lar blocksize.  If the superblock  is  not  found,  e2fsck  will
              terminate with a fatal error.

       -c     This  option  causes  e2fsck  to run the badblocks(8) program to
              find any blocks which are bad on the filesystem, and then  marks
              them  as  bad  by  adding  them to the bad block inode.  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 pro-
              grams which are running e2fsck.  If the file  descriptor  speci-
              fied  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 filesys-
              tems using traditional linear directories.

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

                   ea_ver=extended_attribute_version
                          Assume the format of the extended  attribute  blocks
                          in  the  filesystem is the specified version number.
                          The version number may  be  1  or  2.   The  default
                          extended attribute version format is 2.

       -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  filesys-
              tem 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.
              (Note: if the -c, -l, or -L options are specified in addition to
              the -n option, then the filesystem will be opened read-write, to
              permit  the  bad-blocks  list  to be updated.  However, no other
              changes will be made to the filesystem.)

       -p     Automatically repair ("preen") the file system without any ques-
              tions.

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

       -s     This option will byte-swap the filesystem so that  it  is  using
              the  normalized,  standard  byte-order  (which is i386 or little
              endian).  If the filesystem is already  in  the  standard  byte-
              order, e2fsck will take no action.

       -S     This  option  will  byte-swap  the filesystem, regardless of its
              current byte-order.

       -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.


EXIT CODE

       The  exit  code  returned  by e2fsck is the sum of the following condi-
       tions:
            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.
              (See discussion of the -C option.)

       SIGUSR2
              This signal causes e2fsck to stop displaying a completion bar.


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  tran-
       script  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 filesyste, 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

       mke2fs(8), tune2fs(8), dumpe2fs(8), debugfs(8), e2image(8)



E2fsprogs version 1.38             June 2005                         E2FSCK(8)

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