.\" Copyright (c) 2001 Networks Associates Technology, Inc. .\" All rights reserved. .\" .\" This software was developed for the FreeBSD Project by Chris .\" Costello at Safeport Network Services and NAI Labs, the Security .\" Research Division of Network Associates, Inc. under DARPA/SPAWAR .\" contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS .\" research program. .\" .\" 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. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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. .\" .\" $FreeBSD$ .\" .Dd May 3, 2020 .Dt FFS 7 .Os .Sh NAME .Nm ffs .Nd Berkeley fast file system .Sh SYNOPSIS In the kernel configuration file: .Cd "options FFS" .Cd "options QUOTA" .Cd "options SOFTUPDATES" .Cd "options SUIDDIR" .Cd "options UFS_ACL" .Cd "options UFS_DIRHASH" .Cd "options UFS_EXTATTR" .Cd "options UFS_EXTATTR_AUTOSTART" .Cd "options UFS_GJOURNAL" .Pp In .Xr fstab 5 : .Bd -literal -compact /dev/disk0a /mnt ufs rw 1 1 .Ed .Sh DESCRIPTION The Berkeley fast file system provides facilities to store file system data onto a disk device. .Nm has been optimized over the years for speed and reliability and is the default .Fx file system. .Ss Quotas .Bl -tag -width 2n .It Cd "options QUOTA" This option allows system administrators to set limits on disk usage on a per-user basis. Quotas can be used only on file systems mounted with the .Cm quota option; see .Xr quota 1 and .Xr edquota 8 . .El .Ss Soft Updates .Bl -tag -width 2n .It Cd "options SOFTUPDATES" The soft updates feature tracks writes to the disk and enforces metadata update dependencies (e.g., updating free block maps) to ensure that the file system remains consistent. .Pp To create a new file system with the soft updates enabled, use .Xr newfs 8 command: .Pp .D1 Nm newfs Fl U Ar fs .Pp .Ar fs can be either a mount point listed in .Xr fstab 5 .Pq e.g. , Pa /usr , or a disk device .Pq e.g., Pa /dev/da0a . .Pp It is possible to enable soft updates on an .Em unmounted file system by using .Xr tunefs 8 command: .Pp .D1 Nm tunefs Fl n Cm enable Ar fs .Pp Soft updates can also add journaling that reduces the time spent by .Xr fsck_ffs 8 cleaning up a filesystem after a crash from several minutes to a few seconds. The journal is placed in an inode named .Pa .sujournal , and is kept as a circular log of segments containing records that describe metadata operations. .Pp To create a new file system with both the soft updates and soft updates journaling enabled, use the following command: .Pp .D1 Nm newfs Fl j Ar fs .Pp This runs .Xr tunefs 8 command after .Xr newfs 8 command with .Fl U flag enabled. It is possible to enable soft updates journaling on an .Em unmounted file system by using .Xr tunefs 8 command: .Pp .D1 Nm tunefs Fl j Cm enable Ar fs .Pp This flag automatically enables the soft updates feature when it is not enabled. Note that this .Xr tunefs 8 command will fail if a file .Pa .sujournal already exists before enabling the soft updates journaling. .El .Ss File Ownership Inheritance .Bl -tag -width 2n .It Cd "options SUIDDIR" For use in file sharing environments on networks including .Tn "Microsoft Windows" and .Tn "Apple Macintosh" computers, this option allows files on file systems mounted with the .Cm suiddir option to inherit the ownership of its directory, i.e., .Dq "if it's my directory, it must be my file." .El .Ss Access Control Lists .Bl -tag -width 2n .It Cd "options UFS_ACL" Access control lists allow the association of fine-grained discretionary access control information with files and directories. This option requires the presence of the .Dv UFS_EXTATTR option, and it is recommended that .Dv UFS_EXTATTR_AUTOSTART is included as well, so that ACLs are enabled atomically upon mounting the file system. .El .Pp In order to enable support for ACLs, two extended attributes must be available in the .Dv EXTATTR_NAMESPACE_SYSTEM namespace: .Pa posix1e.acl_access , which holds the access ACL, and .Pa posix1e.acl_default , which holds the default ACL for directories. If you are using file system extended attributes, the following commands may be used to allocate space for and create the necessary EA backing files for ACLs in the root of each file system. In these examples, the root file system is used; see .Sx "Extended Attributes" for more details. .Bd -literal -offset indent mkdir -p /.attribute/system cd /.attribute/system extattrctl initattr -p / 388 posix1e.acl_access extattrctl initattr -p / 388 posix1e.acl_default .Ed .Pp On the next mount of the root file system, the attributes will be automatically started if .Dv UFS_EXTATTR_AUTOSTART is included in the kernel configuration, and ACLs will be enabled. .Ss Directory Hashing .Bl -tag -width 2n .It Cd "options UFS_DIRHASH" Implements a hash-based lookup scheme for directories in order to speed up accesses to very large directories. .El .Ss Extended Attributes .Bl -tag -width 2n .It Cd "options UFS_EXTATTR" Extended attributes allow the association of additional arbitrary metadata with files and directories, which can be assigned and retrieved from userland as well as from within the kernel; see .Xr extattrctl 8 . .It Cd "options UFS_EXTATTR_AUTOSTART" If this option is defined, .Nm will search for a .Pa .attribute subdirectory of the file system root during the mount operation. If found, extended attribute support will be automatically started for that file system. .El .Ss GEOM-based Journaling .Bl -tag -width 2n .It Cd "options UFS_GJOURNAL" Implements a block level journaling of a UFS file system, which is for both data and metadata. To enable this, create a .Xr gjournal 8 GEOM provider for a block device by using the following command: .Pp .D1 Nm gjournal label Ar da0 .Pp In this example, .Pa /dev/da0 is used as the target block device, and .Pa /dev/da0.journal is created. Then create a new file system by using .Xr newfs 8 with the block level journaling flag and mount it: .Pp .D1 Nm newfs Fl J Ar /dev/da0.journal .D1 Nm mount Fl o Cm async Ar /dev/da0.journal Ar /mnt .Pp .Cm async option is not mandatory but recommended for better performance because the journaling guarantees the consistency of an .Cm async mount. .Pp It is also possible to enable the block level journaling on an existing file system. To do so, use .Xr gjournal 8 utility to label the underlying block device and .Xr tunefs 8 utility to enable the block level journaling flag: .Pp .D1 Nm gjournal label Ar da0 .D1 Nm tunefs Fl J Cm enable Ar /dev/da0.journal .D1 Nm mount Fl o Cm async Ar /dev/da0.journal Ar /mnt .El .Ss Xr sysctl 8 MIBs The following .Xr sysctl 8 MIBs are defined for use with .Nm : .Bl -hang -width ".Va vfs.ffs.doreallocblk" .It Va vfs.ffs.doasyncfree Asynchronously write out modified i-node and indirect blocks upon reallocating file system blocks to be contiguous. .Pq Default: 1 . .It Va vfs.ffs.doreallocblks Enable support for the rearrangement of blocks to be contiguous. .Pq Default: 1 . .El .Sh HISTORY The .Nm manual page first appeared in .Fx 4.5 . .Sh SEE ALSO .Xr quota 1 , .Xr acl 3 , .Xr extattr 3 , .Xr edquota 8 , .Xr extattrctl 8 , .Xr fsck_ffs 8 , .Xr sysctl 8 , .Xr tunefs 8 .Rs .%A M. McKusick .%A W. Joy .%A S. Leffler .%A R. Fabry .%D August 1984 .%T "A Fast File System for UNIX" .%J "ACM Transactions on Computer Systems" .%N 2 .%V 3 .%P 181-197 .Re .Rs .%A M. McKusick .%D June 2000 .%T "Soft Updates: A Technique for Eliminating Most Synchronous Writes in the Fast Filesystem" .%J "Proceedings of the Freenix Track at the 1999 Usenix Annual Technical Conference" .%P 71-84 .Re .Rs .%A M. McKusick .%A J. Roberson .%D May 2010 .%T "Journaled Soft-updates" .%J "BSD Canada Conference 2010 (BSDCan)" .Re