1.\" 2.\" Copyright (c) 2006 Ceri Davies 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd August 13, 2019 29.Dt GEOM_UZIP 4 30.Os 31.Sh NAME 32.Nm geom_uzip 33.Nd "GEOM based compressed disk images and partitions" 34.Sh SYNOPSIS 35To compile this driver into the kernel, 36place the following line in your 37kernel configuration file: 38.Bd -ragged -offset indent 39.Cd "device xz" 40.Cd "options zstd" 41.Cd "options GEOM_UZIP" 42.Ed 43.Pp 44Alternatively, to load the driver as a 45module at boot time, place the following line in 46.Xr loader.conf 5 : 47.Bd -literal -offset indent 48geom_uzip_load="YES" 49.Ed 50.Sh DESCRIPTION 51The 52.Nm 53framework provides support for compressed read-only 54disk images. 55This allows significant storage savings at the expense of 56a some CPU time on each read. 57Data written in the GEOM label area allows 58.Nm 59to detect compressed images which have been created with 60.Xr mkuzip 8 61and presented to the kernel as a logical disk device via 62.Xr md 4 . 63.Nm 64creates a unique 65.Pa md#.uzip 66device for each image. 67.Pp 68.Nm 69is not limited to supporting only 70.Xr md 4 71images. 72The image can also reside on a block device. 73.Pq For example, a disk, USB flash drive, DVD-ROM, etc. 74The appropriate device node will appear with the 75.Pa .uzip 76suffix. 77.Bd -literal -offset indent 78# gpart show da0 79=> 0 7833600 da0 BSD (3.7G) 80 0 2097152 1 freebsd-ufs (1.0G) 81 2097152 5736448 - free - (2.7G) 82# gpart add -t freebsd-ufs -s 1G da0 83da0b added 84# dd if=/tmp/20160217_dcomp_zcomp.uzip bs=256k of=/dev/da0b 853190+1 records in 863190+1 records out 87836331008 bytes transferred in 111.021489 secs (7533055 bytes/sec) 88# fsck -t ffs /dev/da0b.uzip 89** /dev/da0b.uzip (NO WRITE) 90** Last Mounted on /mnt 91** Phase 1 - Check Blocks and Sizes 92** Phase 2 - Check Pathnames 93** Phase 3 - Check Connectivity 94** Phase 4 - Check Reference Counts 95** Phase 5 - Check Cyl groups 9697455 files, 604242 used, 184741 free (2349 frags, 22799 blocks, 97 0.3% fragmentation) 98# mount -o ro /dev/da0b.uzip /mnt 99# df /dev/da0b.uzip 100Filesystem 1K-blocks Used Avail Capacity Mounted on 101/dev/da0b.uzip 3155932 2416968 738964 77% /mnt 102.Ed 103.Pp 104The 105.Nm 106device is subsequently used by 107.Fx 108kernel to access the uncompressed data. 109The 110.Nm 111driver does not allow write operations to the underlying disk image. 112To check which 113.Dq providers 114match a given 115.Nm 116device: 117.Bd -literal -offset indent 118# geom uzip list 119Geom name: md1.uzip 120Providers: 1211. Name: md1.uzip 122 Mediasize: 22003712 (21M) 123 Sectorsize: 512 124Consumers: 1251. Name: md1 126 Mediasize: 9563648 (9.1M) 127 Sectorsize: 512 128 129Geom name: da0b.uzip 130Providers: 1311. Name: da0b.uzip 132 Mediasize: 3355443200 (3.1G) 133 Sectorsize: 512 134Consumers: 1351. Name: da0b 136 Mediasize: 1073741824 (1.0G) 137 Sectorsize: 512 138.Ed 139.Pp 140.Nm 141allows mounting the root file system from a compressed disk partition by 142setting the 143.Dv vfs.root.mountfrom 144tunable. 145See 146.Xr loader.conf 5 147for details. 148.Sh DIAGNOSTICS 149Several flags are provided for tracing 150.Nm 151I/O operations and TOC parsing via the following sysctls. 152.Bl -tag -width indent 153.It Va kern.geom.uzip.debug 154Log level. 155Zero disables logging. 156Higher values enable more verbose debug logging for 157.Nm . 158Supported levels are from 0 (no logging) to 4 (maximum amount of logging). 159.It Va kern.geom.uzip.debug_block 160Log operations involving compressed cluster number. 161.El 162.Sh SEE ALSO 163.Xr GEOM 4 , 164.Xr md 4 , 165.Xr geom 8 , 166.Xr mkuzip 8 167.Sh HISTORY 168Zstd support was added in 169.Fx 13.0 . 170.Sh AUTHORS 171.An -nosplit 172The 173.Nm 174driver was written by 175.An Max Khon Aq Mt fjoe@FreeBSD.org . 176The block de-duplication code as well as some 177.Nm 178driver optimizations have been contributed by 179.An Maxim Sobolev Aq Mt sobomax@FreeBSD.org . 180The LZMA decompression support and CLOOP 3.0 support have been added by 181.An Aleksandr Rybalko Aq Mt ray@FreeBSD.org . 182.Pp 183This manual page was written by 184.An Ceri Davies Aq Mt ceri@FreeBSD.org . 185