1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
.\"
.\" Copyright (c) 2006 Ceri Davies
.\" All rights reserved.
.\"
.\" 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 AUTHOR 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 AUTHOR 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 August 13, 2019
.Dt GEOM_UZIP 4
.Os
.Sh NAME
.Nm geom_uzip
.Nd "GEOM based compressed disk images and partitions"
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device xz"
.Cd "options zstd"
.Cd "options GEOM_UZIP"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
geom_uzip_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
framework provides support for compressed read-only
disk images.
This allows significant storage savings at the expense of
a some CPU time on each read.
Data written in the GEOM label area allows
.Nm
to detect compressed images which have been created with
.Xr mkuzip 8
and presented to the kernel as a logical disk device via
.Xr md 4 .
.Nm
creates a unique
.Pa md#.uzip
device for each image.
.Pp
.Nm
is not limited to supporting only
.Xr md 4
images.
The image can also reside on a block device.
.Pq For example, a disk, USB flash drive, DVD-ROM, etc.
The appropriate device node will appear with the
.Pa .uzip
suffix.
.Bd -literal -offset indent
# gpart show da0
=> 0 7833600 da0 BSD (3.7G)
0 2097152 1 freebsd-ufs (1.0G)
2097152 5736448 - free - (2.7G)
# gpart add -t freebsd-ufs -s 1G da0
da0b added
# dd if=/tmp/20160217_dcomp_zcomp.uzip bs=256k of=/dev/da0b
3190+1 records in
3190+1 records out
836331008 bytes transferred in 111.021489 secs (7533055 bytes/sec)
# fsck -t ffs /dev/da0b.uzip
** /dev/da0b.uzip (NO WRITE)
** Last Mounted on /mnt
** Phase 1 - Check Blocks and Sizes
** Phase 2 - Check Pathnames
** Phase 3 - Check Connectivity
** Phase 4 - Check Reference Counts
** Phase 5 - Check Cyl groups
97455 files, 604242 used, 184741 free (2349 frags, 22799 blocks,
0.3% fragmentation)
# mount -o ro /dev/da0b.uzip /mnt
# df /dev/da0b.uzip
Filesystem 1K-blocks Used Avail Capacity Mounted on
/dev/da0b.uzip 3155932 2416968 738964 77% /mnt
.Ed
.Pp
The
.Nm
device is subsequently used by
.Fx
kernel to access the uncompressed data.
The
.Nm
driver does not allow write operations to the underlying disk image.
To check which
.Dq providers
match a given
.Nm
device:
.Bd -literal -offset indent
# geom uzip list
Geom name: md1.uzip
Providers:
1. Name: md1.uzip
Mediasize: 22003712 (21M)
Sectorsize: 512
Consumers:
1. Name: md1
Mediasize: 9563648 (9.1M)
Sectorsize: 512
Geom name: da0b.uzip
Providers:
1. Name: da0b.uzip
Mediasize: 3355443200 (3.1G)
Sectorsize: 512
Consumers:
1. Name: da0b
Mediasize: 1073741824 (1.0G)
Sectorsize: 512
.Ed
.Pp
.Nm
allows mounting the root file system from a compressed disk partition by
setting the
.Dv vfs.root.mountfrom
tunable.
See
.Xr loader.conf 5
for details.
.Sh DIAGNOSTICS
Several flags are provided for tracing
.Nm
I/O operations and TOC parsing via the following sysctls.
.Bl -tag -width indent
.It Va kern.geom.uzip.debug
Log level.
Zero disables logging.
Higher values enable more verbose debug logging for
.Nm .
Supported levels are from 0 (no logging) to 4 (maximum amount of logging).
.It Va kern.geom.uzip.debug_block
Log operations involving compressed cluster number.
.El
.Sh SEE ALSO
.Xr GEOM 4 ,
.Xr md 4 ,
.Xr geom 8 ,
.Xr mkuzip 8
.Sh HISTORY
Zstd support was added in
.Fx 13.0 .
.Sh AUTHORS
.An -nosplit
The
.Nm
driver was written by
.An Max Khon Aq Mt fjoe@FreeBSD.org .
The block de-duplication code as well as some
.Nm
driver optimizations have been contributed by
.An Maxim Sobolev Aq Mt sobomax@FreeBSD.org .
The LZMA decompression support and CLOOP 3.0 support have been added by
.An Aleksandr Rybalko Aq Mt ray@FreeBSD.org .
.Pp
This manual page was written by
.An Ceri Davies Aq Mt ceri@FreeBSD.org .
|
