FSCK_FFS(8) | System Manager's Manual | FSCK_FFS(8) |
fsck_ffs
—
fsck_ffs |
[-adFfPpqUXz ] [-B
byteorder] [-b
block] [-c
level] [-m
mode] [-x
snap-backup] [-y |
-n ] filesystem ... |
fsck_ffs
performs interactive file system consistency
checks and repair for each of the file systems specified on the command line.
It is normally invoked from
fsck(8).
The kernel takes care that only a restricted class of innocuous file system inconsistencies can happen unless hardware or software failures intervene. These are limited to the following:
These are the only inconsistencies that
fsck_ffs
in “preen” mode (with the
-p
option) will correct; if it encounters other
inconsistencies, it exits with an abnormal return status. 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,
fsck_ffs
will print the number of files on that file
system, the number of used and free blocks, and the percentage of
fragmentation.
If sent a QUIT
signal,
fsck_ffs
will finish the file system checks, then
exit with an abnormal return status.
If fsck_ffs
receives a
SIGINFO
signal (see the status
argument for stty(1)), a line
will be written to the standard error output indicating the name of the
device currently being checked, the current phase number and phase-specific
progress information.
Without the -p
option,
fsck_ffs
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 correctable under the -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
yes
or no
. If the operator
does not have write permission on the file system
fsck_ffs
will default to a
-n
action.
fsck_ffs
has more consistency checks than
its predecessors check, dcheck,
fcheck, and icheck combined.
The following flags are interpreted by
fsck_ffs
.
-a
-B
byteorderfsck_ffs
is interrupted
while swapping the metadata byte order, the file system cannot be
recovered. fsck_ffs
will print a message in
interactive mode if the file system is not in host byte order.-b
block-b
option of the
scan_ffs(8) utility can
also be used to find the offset of other super block backups in a file
system.-c
level-O
0 option to
newfs(8).-O
1 option to
newfs(8).Note that FFSv2 file systems are always level 4.
In interactive mode, fsck_ffs
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 file system. In preen mode, 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 converted at once.
The output of dumpfs(8) can be examined to determine the format of the file system (“format” in the second line) and the file system level (“fslevel” in the sixth line).
-d
-F
-f
fsck_ffs
will not check
the file system. This option forces fsck_ffs
to
check the file system, regardless of the state of the clean flag.-m
mode-n
fsck_ffs
except for
‘CONTINUE?
’, which is assumed to be
affirmative; do not open the file system for writing.-P
-p
is specified, in which case only one meter for
overall progress is displayed. Progress meters are disabled if the
-d
option is specified.-p
-q
-U
-X
-x
but uses a file system internal
snapshot on the file system to be checked.-x
snap-backup-n
. See
fss(4) for more details. The
point is to check an internally-consistent version of the filesystem to
find out if it is damaged; on failure one should unmount the filesystem
and repair it.-y
fsck_ffs
; this should be used with great caution
as this is a free license to continue after essentially unlimited trouble
has been encountered.-z
Inconsistencies checked are as follows:
Orphaned files and directories (allocated but unreferenced) are, with the operator's concurrence, reconnected by placing them in the lost+found directory. The name assigned is the inode number. If the lost+found 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.
fsck_ffs
are fully
enumerated and explained in Appendix A of
Fsck - The UNIX File System Check
Program.
fsck
utility appeared in
4.0BSD. It was renamed to
fsck_ffs
in NetBSD 1.3 with
the introduction of a filesystem independent wrapper as
fsck
.
May 4, 2018 | NetBSD 9.4 |