FSCK_UDFS(8) Maintenance Procedures FSCK_UDFS(8)


fsck_udfs - file system consistency check and interactive repair


fsck -F udfs [generic_options] [special ...]

fsck -F udfs [generic_options] [-o specific_options]
[special ...]


fsck audits and interactively repairs inconsistent conditions on file
systems. A file system to be checked can be specified by giving the name
of the block or character special device or by giving the name of its
mount point if a matching entry exists in /etc/vfstab.

special represents the character special device, for example,
/dev/rdsk/c0t2d0s0, on which the file system resides. The character
special device, not the block special device should be used. fsck does
not work on a mounted block device.

If no special device is specified, all udfs file systems specified in the
vfstab file with a fsckdev entry are checked. If the -p (preen) option is
specified, udfs file systems with an fsckpass number greater than 1 are
checked in parallel. See fsck(8).

In the case of correcting serious inconsistencies, by default, fsck asks
for confirmation before making a repair and waits for the operator to
respond with either yes or no. If the operator does not have write
permission on the file system, fsck defaults to the -n (no corrections)
option. See fsck(8).

Repairing some file system inconsistencies can result in loss of data.
The amount and severity of data loss can be determined from the
diagnostic output.

fsck automatically corrects innocuous inconsistencies. It displays a
message for each corrected inconsistency that identifies the nature of
the correction which took place on the file system. After successfully
correcting a file system, fsck prints the number of files on that file
system and the number of used and free blocks.

Inconsistencies checked are as follows:

o Blocks claimed by more than one file or the free list

o Blocks claimed by a file or the free list outside the range of
the file system

o Incorrect link counts in file entries

o Incorrect directory sizes

o Bad file entry format

o Blocks not accounted for anywhere

o Directory checks, file pointing to unallocated file entry and
absence of a parent directory entry

o Descriptor checks, more blocks for files than there are in the
file system

o Bad free block list format

o Total free block count incorrect


The following options are supported:

The following generic_options are supported:

Check but do not repair. This option
checks to be sure that the file system
is suitable for mounting, and returns
the appropriate exit status. If the
file system is ready for mounting, fsck
displays a message such as:

udfs fsck: sanity check: /dev/rdsk/c0t2d0s0 okay

-n | -N
Assume a no response to all questions
asked by fsck; do not open the file
system for writing.

Echo the expanded command line, but do
not execute the command. This option
can be used to verify and to validate
the command line.

-y | -Y
Assume a yes response to all questions
asked by fsck.

-o specific_options
Specify udfs file system specific options in a
comma-separated list with no intervening spaces.
The following specific_options are available:

Force checking of file systems regardless of
the state of their logical volume integrity

Check and fix the file system non-
interactively (preen). Exit immediately if
there is a problem that requires
intervention. This option is required to
enable parallel file system checking.

Check writable file systems only.


List of default parameters for each file system.


vfstab(5), attributes(7), fsck(8), fsdb_udfs(8), fstyp(8), mkfs(8),
mkfs_udfs(8), mountall(8), reboot(8)


The operating system buffers file system data. Running fsck on a mounted
file system can cause the operating system's buffers to become out of
date with respect to the disk. For this reason, use fsck only when the
file system is unmounted. If this is not possible, take care that the
system is quiescent and that it is rebooted immediately after running
fsck. A panic will probably occur if running fsck on a file system that
modifies the file system while it is mounted.

If an unmount of the file system is not done before the system is shut
down, the file system might become corrupted. In this case, a file system
check needs to be completed before the next mount operation.


not writable

You cannot write to the device.

Currently Mounted on

The device is already mounted and cannot run fsck.


File system has been modified to bring it to a consistent state.

Can't read allocation extent

Cannot read the block containing allocation extent.

Bad tag on alloc extent

Invalid tag detected when expecting an allocation extent.

Volume sequence tag error

Invalid tag detected in the volume sequence.

Space bitmap tag error

Invalid tag detected in the space bitmap.


Use fsck in interactive mode.

November 26, 2017 FSCK_UDFS(8)