4.3BSD-Reno/share/man/cat8/fsck.0
FSCK(8) 1990 FSCK(8)
NNAAMMEE
fsck - file system consistency check and interactive repair
SSYYNNOOPPSSIISS
ffsscckk --pp [ --mm mode ]
ffsscckk [ --bb block# ] [ --cc ] [ --yy ] [ --nn ] [ --mm mode ] [
filesystem ] ...
DDEESSCCRRIIPPTTIIOONN
The first form of _f_s_c_k preens a standard set of filesystems
or the specified file systems. It is normally used in the
script //eettcc//rrcc during automatic reboot. Here _f_s_c_k reads the
table //eettcc//ffssttaabb to determine which file systems 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 com-
pletes, 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.
The system takes care that only a restricted class of inno-
cuous inconsistencies can happen unless hardware or software
failures intervene. 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 _f_s_c_k with the --pp
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 file system on
which the correction will take place, and the nature of the
correction. After successfully correcting a file system,
_f_s_c_k will print the number of files on that file system, the
number of used and free blocks, and the percentage of frag-
mentation.
If sent a QUIT signal, _f_s_c_k will finish the file system
checks, then exit with an abnormal return status that causes
an automatic reboot to fail. This is useful when to finish
the file system checks during an automatic reboot, but do
Printed 7/27/90 February 1
FSCK(8) 1990 FSCK(8)
not want the machine to come up multiuser after the checks
complete.
Without the --pp option, _f_s_c_k audits and interactively repairs
inconsistent conditions for file systems. If the file system
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 correct-
able under the --pp 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 con-
sistency correction is to wait for the operator to respond
yyeess or nnoo. If the operator does not have write permission
on the file system _f_s_c_k will default to a --nn action.
_F_s_c_k has more consistency checks than its predecessors
_c_h_e_c_k, _d_c_h_e_c_k, _f_c_h_e_c_k, and _i_c_h_e_c_k combined.
The following flags are interpreted by _f_s_c_k.
--bb Use the block specified immediately after the flag as
the super block for the file system. Block 32 is usu-
ally an alternate super block.
--ll 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.
--mm Use the mode specified in octal immediately after the
flag 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 restrictive set of permissions such as 700.
--yy Assume a yes response to all questions asked by _f_s_c_k;
this should be used with great caution as this is a
free license to continue after essentially unlimited
trouble has been encountered.
--nn Assume a no response to all questions asked by _f_s_c_k
except for ``CONTINUE?'', which is assumed to be
affirmative; do not open the file system for writing.
--cc If the file system is in the old (static table) for-
mat, convert it to the new (dynamic table) format. If
the file system is in the new format, convert it to
the old format provided the old format can support the
filesystem configuration. In interactive mode, _f_s_c_k
will list the direction the conversion is to be made
Printed 7/27/90 February 2
FSCK(8) 1990 FSCK(8)
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 direction
of the conversion is listed and done if possible
without user interaction. Conversion in preen mode is
best used when all the file systems are being con-
verted at once. The format of a file system can be
determined from the first line of output from
_d_u_m_p_f_s(8).
If no filesystems are given to _f_s_c_k then a default list of
file systems is read from the file //eettcc//ffssttaabb.
Inconsistencies checked are as follows:
1. Blocks claimed by more than one inode 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 of proper format.
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.
9. Bad free block map format.
10. 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 lloosstt++ffoouunndd directory. The name assigned is the
inode number. If the _l_o_s_t+_f_o_u_n_d directory 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.
FFIILLEESS
/etc/fstab contains default list of file systems
to check.
DDIIAAGGNNOOSSTTIICCSS
The diagnostics produced by _f_s_c_k are fully enumerated and
explained in Appendix A of ``Fsck - The UNIX File System
Printed 7/27/90 February 3
FSCK(8) 1990 FSCK(8)
Check Program'' (SMM:5).
SSEEEE AALLSSOO
fstab(5), fs(5), fsdb(8), newfs(8), mkfs(8), reboot(8)
Printed 7/27/90 February 4