1.\" $OpenBSD: fsck_ext2fs.8,v 1.19 2022/03/31 17:27:19 naddy Exp $ 2.\" $NetBSD: fsck_ext2fs.8,v 1.1 1997/06/11 11:21:48 bouyer Exp $ 3.\" 4.\" Copyright (c) 1997 Manuel Bouyer. 5.\" Copyright (c) 1980, 1989, 1991, 1993 6.\" The Regents of the University of California. All rights reserved. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)fsck.8 8.3 (Berkeley) 11/29/94 33.\" 34.Dd $Mdocdate: March 31 2022 $ 35.Dt FSCK_EXT2FS 8 36.Os 37.Sh NAME 38.Nm fsck_ext2fs 39.Nd Second Extended File System consistency check and interactive repair 40.Sh SYNOPSIS 41.Nm fsck_ext2fs 42.Op Fl dfnpy 43.Op Fl b Ar block# 44.Op Fl m Ar mode 45.Ar filesystem 46.Sh DESCRIPTION 47.Nm 48performs interactive file system consistency checks and repairs 49the filesystem specified. 50It is normally invoked from 51.Xr fsck 8 . 52.Pp 53The kernel takes care that only a restricted class of innocuous file system 54inconsistencies can happen unless hardware or software failures intervene. 55These are limited to the following: 56.Pp 57.Bl -item -compact -offset indent 58.It 59Unreferenced inodes 60.It 61Link counts in inodes too large 62.It 63Missing blocks in the free map 64.It 65Blocks in the free map also in files 66.It 67Counts in the super-block wrong 68.El 69.Pp 70These are the only inconsistencies that 71.Nm 72in 73.Dq preen 74mode (with the 75.Fl p 76option) will correct; if it encounters other inconsistencies, it exits 77with an abnormal return status. 78For each corrected inconsistency one or more lines will be printed 79identifying the file system on which the correction will take place, 80and the nature of the correction. 81After successfully correcting a file system, 82.Nm 83will print the number of files on that file system 84and the number of used and free blocks. 85.Pp 86If sent a 87.Dv QUIT 88signal, 89.Nm 90will finish the file system checks, then exit with an abnormal return status. 91.Pp 92Without the 93.Fl p 94option, 95.Nm 96audits and interactively repairs inconsistent conditions for the filesystem. 97If the file system is inconsistent, the operator is prompted for concurrence 98before each correction is attempted. 99It should be noted that some of the corrective actions which are not 100correctable under the 101.Fl p 102option will result in some loss of data. 103The amount and severity of data lost may be determined from the diagnostic 104output. 105The default action for each consistency correction 106is to wait for the operator to respond 107.Dq yes 108or 109.Dq no . 110If the operator does not have write permission on the file system, 111.Nm 112will default to a 113.Fl n 114action. 115.Pp 116The following flags are interpreted by 117.Nm fsck_ext2fs : 118.Bl -tag -width indent 119.It Fl b Ar block# 120Use the block specified immediately after the flag as 121the super block for the file system. 122Block 8193 is usually an alternate super block. 123.It Fl d 124Print debugging output. 125.It Fl f 126Force checking of the filesystem. 127Normally, if a file system is cleanly unmounted, the kernel will set a 128.Dq clean flag 129in the file system superblock and 130.Nm 131will not check the file system. 132This option forces 133.Nm 134to check the file system, regardless of the state of the clean flag. 135.It Fl m Ar mode 136Use the 137.Ar mode 138specified in octal as the 139permission bits to use when creating the 140.Pa lost+found 141directory rather than the default 1777. 142In particular, systems that do not wish to have lost files accessible 143by all users on the system should use a more restrictive 144set of permissions such as 700. 145.It Fl n 146Assume a 147.Dq no 148response to all questions asked by 149.Nm 150except for 151.Dq CONTINUE? , 152which is assumed to be affirmative. 153The filesystem will not be opened for writing. 154This is the default for file systems to be checked that are 155concurrently mounted writable. 156.It Fl p 157Specify 158.Dq preen 159mode, described above. 160.It Fl y 161Assume a 162.Dq yes 163response to all questions asked by 164.Nm fsck_ext2fs ; 165this should be used with great caution as this is a free license 166to continue after essentially unlimited trouble has been encountered. 167.El 168.Pp 169If neither of the 170.Fl y 171or 172.Fl n 173options are specified, the user may force 174.Nm 175to assume an answer of 176.Dq yes 177to all the remaining questions by replying to a question with a value of 178.Dq F . 179.Pp 180Inconsistencies checked are as follows: 181.Pp 182.Bl -enum -compact 183.It 184Blocks claimed more than once by inodes or the free map. 185.It 186Blocks claimed by an inode outside the range of the file system. 187.It 188Incorrect link counts. 189.It 190Size checks: 191.Bl -item -compact -offset indent 192.It 193Directory size not a multiple of file system block size. 194.It 195Partially truncated file. 196.El 197.It 198Bad inode format. 199.It 200Blocks not accounted for anywhere. 201.It 202Directory checks: 203.Bl -item -compact -offset indent 204.It 205File pointing to unallocated inode. 206.It 207Inode number out of range. 208.It 209Dot or dot-dot not the first two entries of a directory 210or having the wrong inode number. 211.El 212.It 213Super Block checks: 214.Bl -item -compact -offset indent 215.It 216More blocks for inodes than there are in the file system. 217.It 218Bad free block map format. 219.It 220Total free block and/or free inode count incorrect. 221.El 222.El 223.Pp 224Orphaned files and directories (allocated but unreferenced) are, 225with the operator's concurrence, reconnected by 226placing them in the 227.Pa lost+found 228directory. 229The name assigned is the inode number. 230If the 231.Pa lost+found 232directory does not exist, it is created. 233If there is insufficient space, its size is increased. 234.Pp 235Because of inconsistencies between the block device and the buffer cache, 236the raw device should always be used. 237.Sh DIAGNOSTICS 238The diagnostics produced by 239.Nm 240are fully enumerated and explained in Appendix A of 241.Rs 242.%T "Fsck_ffs \- The UNIX File System Check Program" 243.Re 244.Sh SEE ALSO 245.Xr fs 5 , 246.Xr fstab 5 , 247.Xr fsck 8 , 248.Xr mount_ext2fs 8 , 249.Xr rc 8 250