1.\" Copyright (c) 1980, 1989, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. 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 8.4 (Berkeley) 5/9/95 33.\" $Id: fsck.8,v 1.9 1997/03/11 12:19:36 peter Exp $ 34.\" 35.Dd May 9, 1995 36.Dt FSCK 8 37.Os BSD 4 38.Sh NAME 39.Nm fsck 40.Nd filesystem consistency check and interactive repair 41.Sh SYNOPSIS 42.Nm fsck 43.Fl p 44.Op Fl f 45.Op Fl m Ar mode 46.Nm fsck 47.Op Fl b Ar block# 48.Op Fl c Ar level 49.Op Fl l Ar maxparallel 50.Op Fl y 51.Op Fl n 52.Op Fl m Ar mode 53.Op Ar filesystem 54.Ar ... 55.Sh DESCRIPTION 56The first form of 57.Nm fsck 58preens a standard set of filesystems or the specified filesystems. 59It is normally used in the script 60.Pa /etc/rc 61during automatic reboot. 62Here 63.Nm fsck 64reads the table 65.Pa /etc/fstab 66to determine which filesystems to check. 67Only partitions in fstab that are mounted ``rw,'' ``rq'' or ``ro'' 68and that have non-zero pass number are checked. 69Filesystems with pass number 1 (normally just the root filesystem) 70are checked one at a time. 71When pass 1 completes, all remaining filesystems are checked, 72running one process per disk drive. 73The disk drive containing each filesystem is inferred from the longest prefix 74of the device name that ends in a digit; the remaining characters are assumed 75to be the partition designator. 76.Pp 77The clean flag of each filesystem's superblock is examined and only those filesystems that 78are not marked clean are checked. 79Filesystems are marked clean when they are unmounted, 80when they have been mounted read-only, or when 81.Nm fsck 82runs on them successfully. 83If the 84.Fl f 85option is specified, the filesystems 86will be checked regardless of the state of their clean flag. 87.Pp 88The kernel takes care that only a restricted class of innocuous filesystem 89inconsistencies can happen unless hardware or software failures intervene. 90These are limited to the following: 91.Bl -item -compact 92.It 93Unreferenced inodes 94.It 95Link counts in inodes too large 96.It 97Missing blocks in the free map 98.It 99Blocks in the free map also in files 100.It 101Counts in the super-block wrong 102.El 103.Pp 104These are the only inconsistencies that 105.Nm fsck 106with the 107.Fl p 108option will correct; if it encounters other inconsistencies, it exits 109with an abnormal return status and an automatic reboot will then fail. 110For each corrected inconsistency one or more lines will be printed 111identifying the filesystem on which the correction will take place, 112and the nature of the correction. After successfully correcting a filesystem, 113.Nm fsck 114will print the number of files on that filesystem, 115the number of used and free blocks, 116and the percentage of fragmentation. 117.Pp 118If sent a 119.Dv QUIT 120signal, 121.Nm fsck 122will finish the filesystem checks, then exit with an abnormal 123return status that causes an automatic reboot to fail. 124This is useful when you want to finish the filesystem checks during an 125automatic reboot, 126but do not want the machine to come up multiuser after the checks complete. 127.Pp 128Without the 129.Fl p 130option, 131.Nm fsck 132audits and interactively repairs inconsistent conditions for filesystems. 133If the filesystem is inconsistent the operator is prompted for concurrence 134before each correction is attempted. 135It should be noted that some of the corrective actions which are not 136correctable under the 137.Fl p 138option will result in some loss of data. 139The amount and severity of data lost may be determined from the diagnostic 140output. 141The default action for each consistency correction 142is to wait for the operator to respond 143.Li yes 144or 145.Li no . 146If the operator does not have write permission on the filesystem 147.Nm fsck 148will default to a 149.Fl n 150action. 151.Pp 152.Nm Fsck 153has more consistency checks than 154its predecessors 155.Em check , dcheck , fcheck , 156and 157.Em icheck 158combined. 159.Pp 160The following flags are interpreted by 161.Nm fsck . 162.Bl -tag -width indent 163.It Fl b 164Use the block specified immediately after the flag as 165the super block for the filesystem. Block 32 is usually 166an alternate super block. 167.It Fl l 168Limit the number of parallel checks to the number specified in the following 169argument. 170By default, the limit is the number of disks, running one process per disk. 171If a smaller limit is given, the disks are checked round-robin, one filesystem 172at a time. 173.It Fl m 174Use the mode specified in octal immediately after the flag as the 175permission bits to use when creating the 176.Pa lost+found 177directory rather than the default 1777. 178In particular, systems that do not wish to have lost files accessible 179by all users on the system should use a more restrictive 180set of permissions such as 700. 181.It Fl y 182Assume a yes response to all questions asked by 183.Nm fsck ; 184this should be used with great caution as this is a free license 185to continue after essentially unlimited trouble has been encountered. 186.It Fl n 187Assume a no response to all questions asked by 188.Nm fsck 189except for 190.Ql CONTINUE? , 191which is assumed to be affirmative; 192do not open the filesystem for writing. 193.It Fl c 194Convert the filesystem to the specified level. 195Note that the level of a filesystem can only be raised. 196.Bl -tag -width indent 197There are currently four levels defined: 198.It 0 199The filesystem is in the old (static table) format. 200.It 1 201The filesystem is in the new (dynamic table) format. 202.It 2 203The filesystem supports 32-bit uid's and gid's, 204short symbolic links are stored in the inode, 205and directories have an added field showing the file type. 206.It 3 207If maxcontig is greater than one, 208build the free segment maps to aid in finding contiguous sets of blocks. 209If maxcontig is equal to one, delete any existing segment maps. 210.El 211.Pp 212In interactive mode, 213.Nm fsck 214will list the conversion to be made 215and ask whether the conversion should be done. 216If a negative answer is given, 217no further operations are done on the filesystem. 218In preen mode, 219the conversion is listed and done if 220possible without user interaction. 221Conversion in preen mode is best used when all the filesystems 222are being converted at once. 223The format of a filesystem can be determined from the 224first line of output from 225.Xr dumpfs 8 . 226.El 227.Pp 228If no filesystems are given to 229.Nm fsck 230then a default list of filesystems is read from 231the file 232.Pa /etc/fstab . 233.Pp 234.Bl -enum -indent indent -compact 235Inconsistencies checked are as follows: 236.It 237Blocks claimed by more than one inode or the free map. 238.It 239Blocks claimed by an inode outside the range of the filesystem. 240.It 241Incorrect link counts. 242.It 243Size checks: 244.Bl -item -indent indent -compact 245.It 246Directory size not a multiple of DIRBLKSIZ. 247.It 248Partially truncated file. 249.El 250.It 251Bad inode format. 252.It 253Blocks not accounted for anywhere. 254.It 255Directory checks: 256.Bl -item -indent indent -compact 257.It 258File pointing to unallocated inode. 259.It 260Inode number out of range. 261.It 262Holes in directories. 263.It 264Dot or dot-dot not the first two entries of a directory 265or having the wrong inode number. 266.El 267.It 268Super Block checks: 269.Bl -item -indent indent -compact 270.It 271More blocks for inodes than there are in the filesystem. 272.It 273Bad free block map format. 274.It 275Total free block and/or free inode count incorrect. 276.El 277.El 278.Pp 279Orphaned files and directories (allocated but unreferenced) are, 280with the operator's concurrence, reconnected by 281placing them in the 282.Pa lost+found 283directory. 284The name assigned is the inode number. 285If the 286.Pa lost+found 287directory does not exist, it is created. 288If there is insufficient space its size is increased. 289.Pp 290Because of inconsistencies between the block device and the buffer cache, 291the raw device should always be used. 292.Sh FILES 293.Bl -tag -width /etc/fstab -compact 294.It Pa /etc/fstab 295contains default list of filesystems to check. 296.El 297.Sh DIAGNOSTICS 298The diagnostics produced by 299.Nm fsck 300are fully enumerated and explained in Appendix A of 301.Rs 302.%T "Fsck \- The UNIX File System Check Program" 303.Re 304.Sh SEE ALSO 305.Xr fs 5 , 306.Xr fstab 5 , 307.Xr fsdb 8 , 308.Xr newfs 8 , 309.Xr reboot 8 310