1.\" $NetBSD: fsck_ffs.8,v 1.46 2009/05/07 08:27:14 wiz Exp $ 2.\" 3.\" Copyright (c) 1980, 1989, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)fsck.8 8.3 (Berkeley) 11/29/94 31.\" 32.Dd May 7, 2009 33.Dt FSCK_FFS 8 34.Os 35.Sh NAME 36.Nm fsck_ffs 37.Nd Fast File System consistency check and interactive repair 38.Sh SYNOPSIS 39.Nm 40.Op Fl adFfPpqUX 41.Op Fl B Ar byteorder 42.Op Fl b Ar block 43.Op Fl c Ar level 44.Op Fl m Ar mode 45.Op Fl x Ar snap-backup 46.Op Fl y | n 47.Ar filesystem ... 48.Sh DESCRIPTION 49.Nm 50performs interactive file system consistency checks and repair for each of 51the file systems specified on the command line. 52It is normally invoked from 53.Xr fsck 8 . 54.Pp 55The kernel takes care that only a restricted class of innocuous file system 56inconsistencies can happen unless hardware or software failures intervene. 57These are limited to the following: 58.Pp 59.Bl -item -compact -offset indent 60.It 61Unreferenced inodes 62.It 63Link counts in inodes too large 64.It 65Missing blocks in the free map 66.It 67Blocks in the free map also in files 68.It 69Counts in the super-block wrong 70.El 71.Pp 72These are the only inconsistencies that 73.Nm 74in 75.Dq preen 76mode (with the 77.Fl p 78option) will correct; if it encounters other inconsistencies, it exits 79with an abnormal return status. 80For each corrected inconsistency one or more lines will be printed 81identifying the file system on which the correction will take place, 82and the nature of the correction. 83After successfully correcting a file system, 84.Nm 85will print the number of files on that file system, 86the number of used and free blocks, 87and the percentage of fragmentation. 88.Pp 89If sent a 90.Dv QUIT 91signal, 92.Nm 93will finish the file system checks, then exit with an abnormal return status. 94.Pp 95If 96.Nm 97receives a 98.Dv SIGINFO 99signal 100(see the 101.Sy status 102argument for 103.Xr stty 1 ) , 104a line will be written to the standard error output indicating 105the name of the device currently being checked, the current phase 106number and phase-specific progress information. 107.Pp 108Without the 109.Fl p 110option, 111.Nm 112audits and interactively repairs inconsistent conditions for file systems. 113If the file system is inconsistent the operator is prompted for concurrence 114before each correction is attempted. 115It should be noted that some of the corrective actions which are not 116correctable under the 117.Fl p 118option will result in some loss of data. 119The amount and severity of data lost may be determined from the diagnostic 120output. 121The default action for each consistency correction 122is to wait for the operator to respond 123.Li yes 124or 125.Li no . 126If the operator does not have write permission on the file system 127.Nm 128will default to a 129.Fl n 130action. 131.Pp 132.Nm 133has more consistency checks than 134its predecessors 135.Em check , dcheck , fcheck , 136and 137.Em icheck 138combined. 139.Pp 140The following flags are interpreted by 141.Nm . 142.Bl -tag -width XBXbyteorderXX -offset indent 143.It Fl a 144Interpret the filesystem as an Apple UFS filesystem, even if 145there is no Apple UFS volume label present. 146.It Fl B Ar byteorder 147Convert the file system metadata to 148.Ar byteorder 149byte order if needed. 150Valid byte orders are 151.Dq be 152and 153.Dq le . 154If 155.Nm 156is interrupted while swapping the metadata byte order, the file system cannot 157be recovered. 158.Nm 159will print a message in interactive mode if the file system is not in host 160byte order. 161.It Fl b Ar block 162Use the block number 163.Ar block 164as the super block for the file system. 165Block 32 is usually an alternative super block. 166.It Fl c Ar level 167Convert the FFSv1 file system to the level 168.Ar level . 169Note that the level of a file system can only be raised. 170There are currently five levels defined: 171.Bl -tag -width 3n -offset indent 172.It 0 173The file system is in the old (static table) format. 174.It 1 175The file system is in the new (dynamic table) format. 176.It 2 177The file system supports 32-bit UIDs and GIDs, 178short symbolic links are stored in the inode, 179and directories have an added field showing the file type. 180.It 3 181If maxcontig is greater than one, 182build the free segment maps to aid in finding contiguous sets of blocks. 183If maxcontig is equal to one, delete any existing segment maps. 184.It 4 185Rearrange the super block to the same layout as FFSv2; 186disable the rotational layout tables and per cylinder group 187block totals. 188.El 189.Pp 190In interactive mode, 191.Nm 192will list the conversion to be made 193and ask whether the conversion should be done. 194If a negative answer is given, 195no further operations are done on the file system. 196In preen mode, 197the conversion is listed and done if 198possible without user interaction. 199Conversion in preen mode is best used when all the file systems 200are being converted at once. 201.Pp 202The output of 203.Xr dumpfs 8 204can be examined to determine the format of the file system 205.Dq ( format 206in the second line) 207and the file system level 208.Dq ( fslevel 209in the sixth line). 210.It Fl d 211Print debugging output. 212.It Fl F 213Indicates that 214.Ar filesystem 215is a file system image, rather than a raw character device. 216.Ar filesystem 217will be accessed 218.Sq as-is , 219and no attempts will be made to read a disklabel. 220.It Fl f 221Force checking of file systems. 222Normally, if a file system is cleanly unmounted, the kernel will set a 223.Dq clean flag 224in the file system super block, and 225.Nm 226will not check the file system. 227This option forces 228.Nm 229to check the file system, regardless of the state of the clean flag. 230.It Fl m Ar mode 231Use the octal value 232.Ar mode 233as the permission bits to use when creating the 234.Pa lost+found 235directory rather than the default 1700. 236In particular, systems that do not wish to have lost files accessible 237by all users on the system should use a more restrictive 238set of permissions such as 700. 239.It Fl n 240Assume a no response to all questions asked by 241.Nm 242except for 243.Ql CONTINUE? , 244which is assumed to be affirmative; 245do not open the file system for writing. 246.It Fl P 247Display a progress meter for the file system check. 248A new meter is displayed for each of the 5 file system check passes, unless 249.Fl p 250is specified, in which case only one meter for overall progress is displayed. 251Progress meters are disabled if the 252.Fl d 253option is specified. 254.It Fl p 255Specify 256.Dq preen 257mode, described above. 258.It Fl x Ar snap-backup 259Use a snapshot with 260.Ar snap-backup 261as backup to check a read-write mounted filesystem. 262Must be used with 263.Fl n . 264See 265.Xr fss 4 266for more details. 267The point is to check an internally-consistent version of the 268filesystem to find out if it is damaged; on failure one should unmount 269the filesystem and repair it. 270.It Fl U 271Resolve user ids to usernames. 272.It Fl X 273Similar to 274.Fl x 275but uses a file system internal snapshot on the file system to be checked. 276.It Fl y 277Assume a yes response to all questions asked by 278.Nm ; 279this should be used with great caution as this is a free license 280to continue after essentially unlimited trouble has been encountered. 281.El 282.Pp 283Inconsistencies checked are as follows: 284.Bl -enum -offset indent -compact 285.It 286Blocks claimed by more than one inode or the free map. 287.It 288Blocks claimed by an inode outside the range of the file system. 289.It 290Incorrect link counts. 291.It 292Size checks: 293.Bl -item -offset indent -compact 294.It 295Directory size not a multiple of DIRBLKSIZ. 296.It 297Partially truncated file. 298.El 299.It 300Bad inode format. 301.It 302Blocks not accounted for anywhere. 303.It 304Directory checks: 305.Bl -item -offset indent -compact 306.It 307File pointing to unallocated inode. 308.It 309Inode number out of range. 310.It 311Dot or dot-dot not the first two entries of a directory 312or having the wrong inode number. 313.El 314.It 315Super Block checks: 316.Bl -item -offset indent -compact 317.It 318More blocks for inodes than there are in the file system. 319.It 320Bad free block map format. 321.It 322Total free block and/or free inode count incorrect. 323.El 324.El 325.Pp 326Orphaned files and directories (allocated but unreferenced) are, 327with the operator's concurrence, reconnected by 328placing them in the 329.Pa lost+found 330directory. 331The name assigned is the inode number. 332If the 333.Pa lost+found 334directory does not exist, it is created. 335If there is insufficient space its size is increased. 336.Pp 337Because of inconsistencies between the block device and the buffer cache, 338the raw device should always be used. 339.Sh DIAGNOSTICS 340The diagnostics produced by 341.Nm 342are fully enumerated and explained in Appendix A of 343.Rs 344.%T "Fsck \- The UNIX File System Check Program" 345.Re 346.Sh SEE ALSO 347.Xr fss 4 , 348.Xr fs 5 , 349.Xr fstab 5 , 350.Xr dumpfs 8 , 351.Xr fsck 8 , 352.Xr fsdb 8 , 353.Xr newfs 8 , 354.Xr reboot 8 355