1 .\" Copyright (c) 2001 Networks Associates Technology, Inc.
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4 .\" This software was developed for the FreeBSD Project by Chris
5 .\" Costello at Safeport Network Services and NAI Labs, the Security
6 .\" Research Division of Network Associates, Inc. under DARPA/SPAWAR
7 .\" contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS
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38 .Nd Berkeley fast file system
40 In the kernel configuration file:
43 .Cd "options SOFTUPDATES"
46 .Cd "options UFS_DIRHASH"
47 .Cd "options UFS_EXTATTR"
48 .Cd "options UFS_EXTATTR_AUTOSTART"
53 /dev/disk0a /mnt ufs rw 1 1
56 The Berkeley fast file system
57 provides facilities to store file system data onto a disk device.
59 has been optimized over the years
60 for speed and reliability
66 .It Cd "options QUOTA"
67 This option allows system administrators
68 to set limits on disk usage
70 Quotas can be used only on file systems
81 .It Cd "options SOFTUPDATES"
82 The soft updates feature tracks writes to the disk
83 and enforces metadata update dependencies
84 (e.g., updating free block maps)
85 to ensure that the file system remains consistent.
87 To enable soft updates on an
89 file system, use the following command:
91 .D1 Nm tunefs Fl n Cm enable Ar fs
94 can be either a mount point listed in
102 .Ss File Ownership Inheritance
104 .It Cd "options SUIDDIR"
105 For use in file sharing environments
106 on networks including
107 .Tn "Microsoft Windows"
109 .Tn "Apple Macintosh"
111 this option allows files on file systems
115 to inherit the ownership of its directory,
117 .Dq "if it's my directory, it must be my file."
119 .Ss Access Control Lists
121 .It Cd "options UFS_ACL"
122 Access control lists allow the association of
123 fine-grained discretionary access control information
124 with files and directories.
125 This option requires the presence of the
127 option, and it is recommended that
128 .Dv UFS_EXTATTR_AUTOSTART
130 so that ACLs are enabled atomically upon mounting the file system.
133 In order to enable support for ACLs,
134 two extended attributes must be available in the
135 .Dv EXTATTR_NAMESPACE_SYSTEM
137 .Pa posix1e.acl_access ,
138 which holds the access ACL,
140 .Pa posix1e.acl_default ,
141 which holds the default ACL for directories.
142 If you are using file system extended attributes,
143 the following commands may be used to
144 allocate space for and create the necessary EA backing files
145 for ACLs in the root of each file system.
146 In these examples, the root file system is used;
148 .Sx "Extended Attributes"
150 .Bd -literal -offset indent
151 mkdir -p /.attribute/system
152 cd /.attribute/system
153 extattrctl initattr -p / 388 posix1e.acl_access
154 extattrctl initattr -p / 388 posix1e.acl_default
157 On the next mount of the root file system,
158 the attributes will be automatically started
160 .Dv UFS_EXTATTR_AUTOSTART
161 is included in the kernel configuration),
162 and ACLs will be enabled.
163 .Ss Directory Hashing
165 .It Cd "options UFS_DIRHASH"
166 Implements a hash-based lookup scheme for directories
167 in order to speed up accesses to very large directories.
169 .Ss Extended Attributes
171 .It Cd "options UFS_EXTATTR"
172 Extended attributes allow the association of
173 additional arbitrary metadata with files and directories,
174 which can be assigned and retrieved from userland
175 as well as from within the kernel; see
177 .It Cd "options UFS_EXTATTR_AUTOSTART"
178 If this option is defined,
182 subdirectory of the file system root during the mount operation.
183 If found, extended attribute support will be
184 automatically started for that file system.
189 MIBs are defined for use with
191 .Bl -hang -width ".Va vfs.ffs.doreallocblk"
192 .It Va vfs.ffs.doasyncfree
193 Asynchronously write out modified i-node and indirect blocks
194 upon reallocating file system blocks to be contiguous.
196 .It Va vfs.ffs.doreallocblks
197 Enable support for the rearrangement of blocks
214 .%T "A Fast File System for UNIX"
215 .%J "ACM Transactions on Computer Systems"
223 .%T "Soft Updates: A Technique for Eliminating Most Synchronous Writes in the Fast Filesystem"
224 .%J "Proceedings of the Freenix Track at the 1999 Usenix Annual Technical Conference"