FSCK_EXT2FS(8)          OpenBSD System Manager's Manual         FSCK_EXT2FS(8)

NAME
     fsck_ext2fs - Second Extended File System consistency check and interac-
     tive repair

SYNOPSIS
     fsck_ext2fs [-dfnpy] [-b block#] [-m mode] filesystem ...

DESCRIPTION
     fsck_ext2fs performs interactive file system consistency checks and re-
     pairs for each of the file systems specified.  It is normally invoked
     from fsck(8).

     The kernel takes care that only a restricted class of innocuous file sys-
     tem inconsistencies can happen unless hardware or software failures in-
     tervene.  These are limited to the following:

           Unreferenced inodes
           Link counts in inodes too large
           Missing blocks in the free map
           Blocks in the free map also in files
           Counts in the super-block wrong

     These are the only inconsistencies that fsck_ext2fs in ``preen'' mode
     (with the -p option) will correct; if it encounters other inconsisten-
     cies, it exits with an abnormal return status.  For each corrected incon-
     sistency one or more lines will be printed identifying the file system on
     which the correction will take place, and the nature of the correction.
     After successfully correcting a file system, fsck_ext2fs will print the
     number of files on that file system and the number of used and free
     blocks.

     If sent a QUIT signal, fsck_ext2fs will finish the file system checks,
     then exit with an abnormal return status.

     Without the -p option, fsck_ext2fs audits and interactively repairs in-
     consistent conditions for file systems.  If the file system is inconsis-
     tent, the operator is prompted for concurrence before each correction is
     attempted.  It should be noted that some of the corrective actions which
     are not correctable under the -p option will result in some loss of data.
     The amount and severity of data lost may be determined from the diagnos-
     tic output.  The default action for each consistency correction is to
     wait for the operator to respond ``yes'' or ``no''.  If the operator does
     not have write permission on the file system, fsck_ext2fs will default to
     a -n action.

     The following flags are interpreted by fsck_ext2fs:

     -b block#
             Use the block specified immediately after the flag as the super
             block for the file system.  Block 8193 is usually an alternate
             super block.

     -d      Print debugging output.

     -f      Force checking of file systems.  Normally, if a file system is
             cleanly unmounted, the kernel will set a ``clean flag'' in the
             file system superblock and fsck_ext2fs will not check the file
             system.  This option forces fsck_ext2fs to check the file system,
             regardless of the state of the clean flag.

     -m mode
             Use the mode specified in octal as the permission bits to use
             when creating the lost+found directory rather than the default
             1777.  In particular, systems that do not wish to have lost files
             accessible by all users on the system should use a more restric-
             tive set of permissions such as 700.

     -n      Assume a ``no'' response to all questions asked by fsck_ext2fs
             except for ``CONTINUE?'', which is assumed to be affirmative.
             File systems will not be opened for writing.  This is the default
             for file systems to be checked that are concurrently mounted
             writable.

     -p      Specify ``preen'' mode, described above.

     -y      Assume a ``yes'' response to all questions asked by fsck_ext2fs;
             this should be used with great caution as this is a free license
             to continue after essentially unlimited trouble has been encoun-
             tered.

     Inconsistencies checked are as follows:

     1.   Blocks claimed more than once by inodes or the free map.
     2.   Blocks claimed by an inode outside the range of the file system.
     3.   Incorrect link counts.
     4.   Size checks:
                Directory size not a multiple of file system block size.
                Partially truncated file.
     5.   Bad inode format.
     6.   Blocks not accounted for anywhere.
     7.   Directory checks:
                File pointing to unallocated inode.
                Inode number out of range.
                Dot or dot-dot not the first two entries of a directory or
                having the wrong inode number.
     8.   Super Block checks:
                More blocks for inodes than there are in the file system.
                Bad free block map format.
                Total free block and/or free inode count incorrect.

     Orphaned files and directories (allocated but unreferenced) are, with the
     operator's concurrence, reconnected by placing them in the lost+found di-
     rectory.  The name assigned is the inode number.  If the lost+found di-
     rectory does not exist, it is created.  If there is insufficient space
     its size is increased.

     Because of inconsistencies between the block device and the buffer cache,
     the raw device should always be used.

DIAGNOSTICS
     The diagnostics produced by fsck_ext2fs are fully enumerated and ex-
     plained in Appendix A of Fsck_ffs - The UNIX File System Check Program.

SEE ALSO
     fs(5), fstab(5), fsck(8), mount_ext2fs(8), rc(8)

OpenBSD 4.7                    January 10, 2010                              2
