Provided by: e2fsprogs_1.47.0-1ubuntu1_amd64 bug


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


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


       e2fsck is used to check the ext2/ext3/ext4 family of file systems.  For ext3 and ext4 file
       systems 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 file systems that use journaling, e2fsck will
       normally replay the journal  and  exit,  unless  its  superblock  indicates  that  further
       checking is required.

       device is a block device (e.g., /dev/sdc1) or file containing the file system.

       Note  that  in  general  it  is  not safe to run e2fsck on mounted file systems.  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
       file system is mounted.   If e2fsck asks whether or not you should  check  a  file  system
       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.

       If e2fsck is run in interactive mode (meaning that none of -y, -n, or -p  are  specified),
       the program will ask the user to fix each problem found in the file system.  A response of
       'y' will fix the error; 'n' will leave the error unfixed; and 'a' will fix the problem and
       all  subsequent  problems; pressing Enter will proceed with the default response, which is
       printed before the question mark.  Pressing Control-C terminates e2fsck immediately.


       -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 backup superblocks is dependent on the file system's
              blocksize, the number of blocks per group, and features such as sparse_super.

              Additional backup superblocks can be determined by using the mke2fs  program  using
              the  -n  option  to  print  out  where  the  superblocks exist, supposing mke2fs is
              supplied with arguments that are consistent with the  file  system's  layout  (e.g.
              blocksize, blocks per group, sparse_super, etc.).

              If  an  alternative superblock is specified and the file system is not opened read-
              only, e2fsck will make sure that the primary superblock  is  updated  appropriately
              upon completion of the file system 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 file system 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 file system.  This option causes e2fsck to try to  optimize
              all  directories,  either by re-indexing them if the file system supports directory
              indexing,  or by sorting and compressing directories for  smaller  directories,  or
              for file systems 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 file system 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:

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

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

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

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

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

                          Do not offer to optimize the extent  tree  by  eliminating  unnecessary
                          width  or  depth.   This  can also be enabled in the options section of

                          Offer to optimize the extent tree by eliminating unnecessary  width  or
                          depth.    This   is   the   default   unless   otherwise  specified  in

                          Trade off using memory for speed when checking a  file  system  with  a
                          large  number  of  hard-linked files.  The amount of memory required is
                          proportional to the number of inodes in the  file  system.   For  large
                          file  systems,  this  can be gigabytes of memory.  (For example, a 40TB
                          file system with 2.8 billion inodes will consume an additional  5.7  GB
                          memory if this optimization is enabled.)  This optimization can also be
                          enabled in the options section of /etc/e2fsck.conf.

                          Disable the inode_count_fullmap  optimization.   This  is  the  default
                          unless otherwise specified in /etc/e2fsck.conf.

                          Use  this  many  KiB  of  memory  to pre-fetch metadata in the hopes of
                          reducing e2fsck runtime.  By default, this is set to the  size  of  two
                          block  groups'  inode  tables  (typically  4MiB  on a regular ext4 file
                          system); if this amount is more than 1/50th of total  physical  memory,
                          readahead is disabled.  Set this to zero to disable readahead entirely.

                          Convert block-mapped files to extent-mapped files.

                          Only  fix  damaged  metadata;  do  not  optimize  htree  directories or
                          compress extent trees.  This option is incompatible with the -D and  -E
                          bmap2extent options.

                          Force   verification   of   encoded   filenames   in   case-insensitive
                          directories.  This is the default mode  if  the  file  system  has  the
                          strict flag enabled.

                          If  the file system has shared blocks, with the shared blocks read-only
                          feature enabled, then this will unshare all shared blocks and unset the
                          read-only  feature  bit.  If  there  is  not enough free space then the
                          operation will fail.  If the file system does not  have  the  read-only
                          feature  bit,  but has shared blocks anyway, then this option will have
                          no effect. Note when using this option, if there is no  free  space  to
                          clone  blocks,  there  is  no  prompt  to  delete files and instead the
                          operation will fail.

                          Note that unshare_blocks implies the "-f" option  to  ensure  that  all
                          passes  are  run.  Additionally, if "-n" is also specified, e2fsck will
                          simulate trying to allocate enough space to deduplicate. If this fails,
                          the exit code will be non-zero.

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

       -F     Flush  the file system 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 file system 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  file  system.   Hence,  badblocks(8)  must  be given the blocksize of the file
              system 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 file system 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 file system 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

       -z undo_file
              Before  overwriting  a file system block, write the old contents of the block to an
              undo file.  This undo file can be used with e2undo(8) to restore the  old  contents
              of the file system should something go wrong.  If the empty string is passed as the
              undo_file argument, the  undo  file  will  be  written  to  a  file  named  e2fsck-
              device.e2undo  in  the  directory  specified via the E2FSPROGS_UNDO_DIR environment

              WARNING: The undo file cannot be used to recover from a power or system crash.


       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


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

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

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


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

       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 file system 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 file system, 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.


              Determines the location of the configuration file (see e2fsck.conf(5)).


       This version of e2fsck was written by Theodore Ts'o <>.


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