.\" Copyright (c) 1980, 1989, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)fsck.8 8.2 (Berkeley) 12/11/93 .\" .Dd December 11, 1993 .Dt FSCK 8 .Os BSD 4 .Sh NAME .Nm fsck .Nd filesystem consistency check and interactive repair .Sh SYNOPSIS .Nm fsck .Fl p .Op Fl m Ar mode .Nm fsck .Op Fl b Ar block# .Op Fl c Ar level .Op Fl l Ar maxparallel .Op Fl y .Op Fl n .Op Fl m Ar mode .Op Ar filesystem .Ar ... .Sh DESCRIPTION The first form of .Nm fsck preens a standard set of filesystems or the specified filesystems. It is normally used in the script .Pa /etc/rc during automatic reboot. Here .Nm fsck reads the table .Pa /etc/fstab to determine which filesystems to check. Only partitions in fstab that are mounted ``rw,'' ``rq'' or ``ro'' and that have non-zero pass number are checked. Filesystems with pass number 1 (normally just the root filesystem) are checked one at a time. When pass 1 completes, all remaining filesystems are checked, running one process per disk drive. The disk drive containing each filesystem is inferred from the longest prefix of the device name that ends in a digit; the remaining characters are assumed to be the partition designator. .Pp The kernel takes care that only a restricted class of innocuous filesystem inconsistencies can happen unless hardware or software failures intervene. These are limited to the following: .Bl -item -compact .It Unreferenced inodes .It Link counts in inodes too large .It Missing blocks in the free map .It Blocks in the free map also in files .It Counts in the super-block wrong .El .Pp These are the only inconsistencies that .Nm fsck with the .Fl p option will correct; if it encounters other inconsistencies, it exits with an abnormal return status and an automatic reboot will then fail. For each corrected inconsistency one or more lines will be printed identifying the filesystem on which the correction will take place, and the nature of the correction. After successfully correcting a filesystem, .Nm fsck will print the number of files on that filesystem, the number of used and free blocks, and the percentage of fragmentation. .Pp If sent a .Dv QUIT signal, .Nm fsck will finish the filesystem checks, then exit with an abnormal return status that causes an automatic reboot to fail. This is useful when you want to finish the filesystem checks during an automatic reboot, but do not want the machine to come up multiuser after the checks complete. .Pp Without the .Fl p option, .Nm fsck audits and interactively repairs inconsistent conditions for filesystems. If the filesystem is inconsistent 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 .Fl p option will result in some loss of data. The amount and severity of data lost may be determined from the diagnostic output. The default action for each consistency correction is to wait for the operator to respond .Li yes or .Li no . If the operator does not have write permission on the filesystem .Nm fsck will default to a .Fl n action. .Pp .Nm Fsck has more consistency checks than its predecessors .Em check , dcheck , fcheck , and .Em icheck combined. .Pp The following flags are interpreted by .Nm fsck . .Bl -tag -width indent .It Fl b Use the block specified immediately after the flag as the super block for the filesystem. Block 32 is usually an alternate super block. .It Fl l Limit the number of parallel checks to the number specified in the following argument. By default, the limit is the number of disks, running one process per disk. If a smaller limit is given, the disks are checked round-robin, one filesystem at a time. .It Fl m Use the mode specified in octal immediately after the flag as the permission bits to use when creating the .Pa 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 restrictive set of permissions such as 700. .It Fl y Assume a yes response to all questions asked by .Nm fsck ; this should be used with great caution as this is a free license to continue after essentially unlimited trouble has been encountered. .It Fl n Assume a no response to all questions asked by .Nm fsck except for .Ql CONTINUE? , which is assumed to be affirmative; do not open the filesystem for writing. .It Fl c Convert the filesystem to the specified level. Note that the level of a filesystem can only be raised. .Bl -tag -width indent There are currently three levels defined: .It 0 The filesystem is in the old (static table) format. .It 1 The filesystem is in the new (dynamic table) format. .It 2 The filesystem supports 32-bit uid's and gid's, short symbolic links are stored in the inode, and directories have an added field showing the file type. .El .Pp In interactive mode, .Nm fsck will list the conversion to be made and ask whether the conversion should be done. If a negative answer is given, no further operations are done on the filesystem. In preen mode, the conversion is listed and done if possible without user interaction. Conversion in preen mode is best used when all the filesystems are being converted at once. The format of a filesystem can be determined from the first line of output from .Xr dumpfs 8 . .El .Pp If no filesystems are given to .Nm fsck then a default list of filesystems is read from the file .Pa /etc/fstab . .Pp .Bl -enum -indent indent -compact Inconsistencies checked are as follows: .It Blocks claimed by more than one inode or the free map. .It Blocks claimed by an inode outside the range of the filesystem. .It Incorrect link counts. .It Size checks: .Bl -item -indent indent -compact .It Directory size not a multiple of DIRBLKSIZ. .It Partially truncated file. .El .It Bad inode format. .It Blocks not accounted for anywhere. .It Directory checks: .Bl -item -indent indent -compact .It File pointing to unallocated inode. .It Inode number out of range. .It Dot or dot-dot not the first two entries of a directory or having the wrong inode number. .El .It Super Block checks: .Bl -item -indent indent -compact .It More blocks for inodes than there are in the filesystem. .It Bad free block map format. .It Total free block and/or free inode count incorrect. .El .El .Pp Orphaned files and directories (allocated but unreferenced) are, with the operator's concurrence, reconnected by placing them in the .Pa lost+found directory. The name assigned is the inode number. If the .Pa lost+found directory does not exist, it is created. If there is insufficient space its size is increased. .Pp Because of inconsistencies between the block device and the buffer cache, the raw device should always be used. .Sh FILES .Bl -tag -width /etc/fstab -compact .It Pa /etc/fstab contains default list of filesystems to check. .El .Sh DIAGNOSTICS The diagnostics produced by .Nm fsck are fully enumerated and explained in Appendix A of .Rs .%T "Fsck \- The UNIX File System Check Program" .Re .Sh SEE ALSO .Xr fstab 5 , .Xr fs 5 , .Xr fsdb 8 , .Xr newfs 8 , .Xr mkfs 8 , .Xr reboot 8
