NAME
fsck - check and repair a Linux filesystemSYNOPSIS
fsck [-lsAVRTMNP] [-r [fd]] [-C [fd]] [ -t fstype] [filesystem...] [--] [fs-specific-options]DESCRIPTION
fsck is used to check and optionally repair one or more Linux filesystems. filesystem can be a device name (e.g., /dev/hdc1, /dev/sdb2), a mount point (e.g., /, /usr, /home), or an filesystem label or UUID specifier (e.g., UUID=8868abf6-88c5-4a83-98b8-bfc24057f7bd or LABEL=root). Normally, the fsck program will try to handle filesystems on different physical disk drives in parallel to reduce the total amount of time needed to check all of them.No errors
Filesystem errors corrected
System should be rebooted
Filesystem errors left uncorrected
Operational error
Usage or syntax error
Checking canceled by user request
Shared-library error
OPTIONS
-lCreate an exclusive flock(2) lock file
( /run/fsck/<diskname>.lock) for whole-disk device. This option
can be used with one device only (this means that -A and -l are
mutually exclusive). This option is recommended when more fsck
instances are executed in the same time. The option is ignored when used for
multiple devices or for non-rotating disks. fsck does not lock
underlying devices when executed to check stacked devices (e.g. MD or DM) -
this feature is not implemented yet.
Report certain statistics for each fsck when
it completes. These statistics include the exit status, the maximum run set
size (in kilobytes), the elapsed all-clock time and the user and system CPU
time used by the fsck run. For example:
/dev/sda1: status 0, rss 92828, real 4.002804, user 2.677592, sys 0.86186
GUI front-ends may specify a file descriptor fd, in which case the
progress bar information will be sent to that file descriptor in a machine
parsable format. For example:
/dev/sda1 0 92828 4.002804 2.677592 0.86186
Serialize fsck operations. This is a
good idea if you are checking multiple filesystems and the checkers are in an
interactive mode. (Note: e2fsck(8) runs in an interactive mode by
default. To make e2fsck(8) run in a non-interactive mode, you must
either specify the -p or -a option, if you wish for errors to be
corrected automatically, or the -n option if you do not.)
Specifies the type(s) of filesystem to be
checked. When the -A flag is specified, only filesystems that match
fslist are checked. The fslist parameter is a comma-separated
list of filesystems and options specifiers. All of the filesystems in this
comma-separated list may be prefixed by a negation operator ' no' or
'!', which requests that only those filesystems not listed in
fslist will be checked. If none of the filesystems in fslist is
prefixed by a negation operator, then only those listed filesystems will be
checked.
Options specifiers may be included in the comma-separated fslist. They
must have the format opts=fs-option. If an options specifier is
present, then only filesystems which contain fs-option in their mount
options field of /etc/fstab will be checked. If the options specifier
is prefixed by a negation operator, then only those filesystems that do not
have fs-option in their mount options field of /etc/fstab will
be checked.
For example, if opts=ro appears in fslist, then only filesystems
listed in /etc/fstab with the ro option will be checked.
For compatibility with Mandrake distributions whose boot scripts depend upon an
unauthorized UI change to the fsck program, if a filesystem type of
loop is found in fslist, it is treated as if opts=loop
were specified as an argument to the -t option.
Normally, the filesystem type is deduced by searching for filesys in the
/etc/fstab file and using the corresponding entry. If the type cannot
be deduced, and there is only a single filesystem given as an argument to the
-t option, fsck will use the specified filesystem type. If this
type is not available, then the default filesystem type (currently ext2) is
used.
Walk through the /etc/fstab file and
try to check all filesystems in one run. This option is typically used from
the /etc/rc system initialization file, instead of multiple commands
for checking a single filesystem.
The root filesystem will be checked first unless the -P option is
specified (see below). After that, filesystems will be checked in the order
specified by the fs_passno (the sixth) field in the /etc/fstab
file. Filesystems with a fs_passno value of 0 are skipped and are not
checked at all. Filesystems with a fs_passno value of greater than zero
will be checked in order, with filesystems with the lowest fs_passno
number being checked first. If there are multiple filesystems with the same
pass number, fsck will attempt to check them in parallel, although it
will avoid running multiple filesystem checks on the same physical disk.
fsck does not check stacked devices (RAIDs, dm-crypt, ...) in parallel
with any other device. See below for FSCK_FORCE_ALL_PARALLEL setting.
The /sys filesystem is used to determine dependencies between devices.
Hence, a very common configuration in /etc/fstab files is to set the root
filesystem to have a fs_passno value of 1 and to set all other
filesystems to have a fs_passno value of 2. This will allow fsck
to automatically run filesystem checkers in parallel if it is advantageous to
do so. System administrators might choose not to use this configuration if
they need to avoid multiple filesystem checks running in parallel for some
reason - for example, if the machine in question is short on memory so that
excessive paging is a concern.
fsck normally does not check whether the device actually exists before
calling a filesystem specific checker. Therefore non-existing devices may
cause the system to enter filesystem repair mode during boot if the filesystem
specific checker returns a fatal error. The /etc/fstab mount option
nofail may be used to have fsck skip non-existing devices.
fsck also skips non-existing devices that have the special filesystem
type auto.
Display completion/progress bars for those
filesystem checkers (currently only for ext[234]) which support them.
fsck will manage the filesystem checkers so that only one of them will
display a progress bar at a time. GUI front-ends may specify a file descriptor
fd, in which case the progress bar information will be sent to that
file descriptor.
Do not check mounted filesystems and return an
exit status of 0 for mounted filesystems.
Don’t execute, just show what would be
done.
When the -A flag is set, check the root
filesystem in parallel with the other filesystems. This is not the safest
thing in the world to do, since if the root filesystem is in doubt things like
the e2fsck(8) executable might be corrupted! This option is mainly
provided for those sysadmins who don’t want to repartition the root
filesystem to be small and compact (which is really the right solution).
When checking all filesystems with the
-A flag, skip the root filesystem. (This is useful in case the root
filesystem has already been mounted read-write.)
Don’t show the title on startup.
Produce verbose output, including all
filesystem-specific commands that are executed.
Display help text and exit.
Display version information and exit.
FILESYSTEM SPECIFIC OPTIONS
Options which are not understood by fsck are passed to the filesystem-specific checker!ENVIRONMENT
The fsck program’s behavior is affected by the following environment variables:If this environment variable is set,
fsck will attempt to check all of the specified filesystems in
parallel, regardless of whether the filesystems appear to be on the same
device. (This is useful for RAID systems or high-end storage systems such as
those sold by companies such as IBM or EMC.) Note that the fs_passno
value is still used.
This environment variable will limit the
maximum number of filesystem checkers that can be running at one time. This
allows configurations which have a large number of disks to avoid fsck
starting too many filesystem checkers at once, which might overload CPU and
memory resources available on the system. If this value is zero, then an
unlimited number of processes can be spawned. This is currently the default,
but future versions of fsck may attempt to automatically determine how
many filesystem checks can be run based on gathering accounting data from the
operating system.
The PATH environment variable is used
to find filesystem checkers.
This environment variable allows the system
administrator to override the standard location of the /etc/fstab file.
It is also useful for developers who are testing fsck.
enables libblkid debug output.
enables libmount debug output.
FILES
/etc/fstabAUTHORS
Theodore <[email protected]>>Ts’o Karel <[email protected]>ZakSEE ALSO
fstab(5), mkfs(8), fsck.ext2(8) or fsck.ext3(8) or e2fsck(8), fsck.cramfs(8), fsck.jfs(8), fsck.nfs(8), fsck.minix(8), fsck.msdos(8), fsck.vfat(8), fsck.xfs(8), reiserfsck(8)REPORTING BUGS
For bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>.AVAILABILITY
The fsck command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.2022-05-11 | util-linux 2.38.1 |